Advances in Research on Chemical Constituents and Their Biological Activities of the Genus Actinidia

Abstract

Kiwi, a fruit from plants of the genus Actinidia, is one of the famous fruits with thousand years of edible history. In the past twenty years, a great deal of research has been done on the chemical constituents of the Actinidia species. A large number of secondary metabolites including triterpenoids, flavonoids, phenols, etc. have been identified from differents parts of Actinidia plants, which exhibited significant in vitro and in vivo pharmacological activities including anticancer, anti-inflammatory, neuroprotective, anti-oxidative, anti-bacterial, and anti-diabetic activities. In order to fully understand the chemical components and biological activities of Actinidia plants, and to improve their further research, development and utilization, this review summarizes the compounds extracted from different parts of Actinidia plants since 1959 to 2020, classifies the types of constituents, reports on the pharmacological activities of relative compounds and medicinal potentials.

Introduction

With the development of natural product research, a huge number of chemical constituents have been identified from natural resources. There is no doubt that the research on the chemical composition of fruits, including trace elements, has greatly improved the application prospects of these fruits. With no exception, it is the same to kiwifruit, one of the most prestigious fruits with a long history of eating [1, 2]. Kiwi belongs to plants of the genus Actinidia comprising more than 70 species around the world [3]. Some of these plants are proven to have a wide range of medicinal activities. For example, A. valvata, whose root is known as ‘‘Mao-Ren-Shen” in traditional Chinese medicine, exhibits antitumor and anti-inflammatory activities and has been used for the treatment of hepatoma, lung carcinoma and myeloma for a long time [4, 5]. The roots of A. chinensis Planch, called “Teng-Li-Gen” usually, were used as a traditional Chinese medicine for the treatment of various cancers, such as esophagus cancer, liver cancer, and gastric cancer [6]. In the past two decades, great research had been accomplished about exploring the chemical composition of Actinidia plants. These studies have greatly promoted the understanding of the chemical components and functions of the Actinidia plant. According to literature survey, 12 Actinidia species including A. valvata, A. chinensis, A. argute, A. polygama, A. kolomikta, A. eriantha, A. macrosperma, A. deliciosa, A. chrysantha, A. rufa, A. indochinensis, and A. valvata were reported for their natural products. This review systematically summarizes the chemical components and their biological activities from different parts of 12 Actinidia species from 1959 to 2020. According to structure types, a total of 325 molecules have been collected including terpeniods, phenols, and other small groups (Fig. 1). Names and isolation information were listed in the tables, while the biological activities of the extracts or compounds were discussed in the text.

Fig. 1.

Constituents proportion of 12 Actinidia plants

Chemical Constituents

Terpenoids

In recent years, a large number of terpenoids were isolated from many Actinidia species. Among them, triterpenes account for the vast majority that are mainly composed by several normal frameworks including ursane-type, oleanane-type, and lupane-type. Of the total 325 compounds in this review, 104 are triterpenoids. From the literature review, ursolic acids and their saponins are undoubtedly the most abundant in Actinidia species.

Ursane Triterpenoids

Ursane-type triterpenes are characterized of ursolic acid and its saponins, possessing a 6/6/6/6/6-fused carbon skeleton. A total of 76 ursane-type triterpenoids (1–76) have been identified from plants of the genus Actinidia (Fig. 2, Table 1). Ursolic acid (3β-Hydroxyurs-12-en-28-oic acid 1) [7], is one of the most frequently obtained compound in many kinds of kiwifruit plants with unique flavor. Great attention had been paid on biological activities about ursolic acid, attracting much interest in recent years. Ursolic acid exhibits different pharmacological activities, including anti-cancer, amylolytic enzyme inhibitors, cytotoxicity, downregulating thymic stromal lymphopoietin and others [7–11].

Fig. 2.

Structures of ursane triterpenoids 1‒76 from Actinidia plants

Table 1.

Information of ursane triterpenoids from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
1	3β-Hydroxyurs-12-en-28-oic acid	A. eriantha [7]	Roots	Anticancer (in vitro) [8] Inhibiting amylolytic enzyme (in vitro) [9] Antidepressant and neuroprotective (in vitro) [10] Downregulating thymic stromal lymphopoietin (in vitro) [11]
2	3β,24-Dihydroxyurs-12-en-28-oic acid	A. arguta [37] A. polygama [23]	Leaves Fruit galls
3	2α,3β-Dihydroxyurs-12-en-28-oic acid	A. polygama [23] A. arguta [13]	Fruit galls Roots	Anti-metastation (In vitro) [38] Anticancer (In vitro) [12]
4	23-Hydroxyursolic acid	A. arguta [13]	Roots	Anti-pancreatic lipase (In vitro) [13] Anticancer(In vitro) [14–16] Anti-inflammatory (in vitro) [17]
5	2β,3β-Dihydroxyursolic acid	A. sp [39]
6	2α,3α-Dihydroxyurs-12-en-28-oic acid	A. chinensis [30]	Roots
7	2α,3α,24-Trihydroxyurs-12-en-28-oic acid	A. eriantha [40]	Roots
8	2α,3β,24-Trihydroxy-urs-12-en-28-oic acid	A. eriantha Benth [41] A. polygama [18]	Fruit galls	Against A549, LOVO, and HepG2 cell lines (in vitro) [19]
9	2α,3β,23-Trihydroxyurs-12-en-28-oic acid	A. polygama [18] A. chrysantha [42]	Fruit galls Roots	Against A549, LOVO, and HepG2 cell lines (in vitro) [19]
10	2α,3α,23-Trihydroxyurs-12-en-28-oic acid	A. polygama [18]	Fruit galls
11	2β,3α,24-Trihydroxy-urs-12-en-28-oic acid	A. rufa [43]	Roots
12	2β,3β,10-Trihydroxy ursolic acid	A. sp [39]
13	2α,3β,14β-Trihydroxy ursolic acid	A. sp [39]
14	2α,3α,19-Trihydroxyurs-12-en-28-oic acid	A. chinensis [44]	Roots	Inhibiting tumor angiogenesis (in vitro) [45]
15	2β,3β,23-Trihydroxyurs-12-en-28-oic acid	A. eriantha [7]	Roots	Against HepG2, A549, MCF-7, SK-OV-3, and HeLa cell lines (in vitro) [32]
16	2β,3α,23-Trihydroxyurs-12-en-28-oic acid	A. chinensis Planch [32]	Roots	Against HepG2, A549, MCF-7, SK-OV-3, and HeLa cell lines (in vitro) [32]
17	2α,3α,23,24-Tetrahydroxyurs-12-en-28-oic acid	A. polygama [18]	Fruit galls	Against A549, LOVO and HepG2 cell lines (in vitro) [20]
18	2α, 3β, 19α, 23-Tetrahydroxyurs-12-en-28-oic acid	A. chinensis Planch [32]	Roots
19	2α,3β,19α,24-Tetrahydroxyurs-12-en-28-oic acid	A. indochinensis Merr. Var [46]	Roots
20	2α,3α,19α,24-Tetrahydroxyurs-12-en-28-oic acid	A. valvata [21]	Leaves	Anti-tumor (in vitro) [21]
21	2α,3β,23,24-Tetrahydroxyurs-12-en-28-oic acid	A. chinensis Planch [32]	Roots
22	2α,3β,6β,23-Tetrahydroxyurs-12-en-28-oic acid	A. valvata Dunn [47]	Roots
23	2α,3β,23,27-Tetrahydroxy-12-en-28-ursolic acid	A. deliciosa [48]	Roots
24	2α,3α,19α,23,24-Pentahydroxy-urs-12-en- 28-oic acid	A. chinensis Planch [19]	Roots
25	2α,3β,19α,23,24-Pentahydroxyurs-12-en-28-oic acid	A. rufa Planch ex miq [43]	Roots
26	(2β,3α,6α)-2,3,6,20,23,30-Hexahydroxyurs-12-en-28-oic acid	A. valvata Dunn [22]	Roots	Against BEL-7402 and SMMC-7721 cells lines (in vitro) [22]
27	2β,3β-Dihydroxy-23-oxours-12-en-28-oic acid	A. eriantha Benth [49]	Roots
28	2α,3α-Dihydroxyurs-12-ene-24-al-28-oic acid	A. polygama [18]	Fruit galls
29	2α,3α,24-Trihydroxyurs-12-ene-23,28-dioic acid	A. polygama [18]	Fruit galls
30	3β-O-Acetylursolic acid	A. polygama [23]	Fruit galls	Inhibiting PTP1B (in vitro) [24]
31	24-Acetyloxy-2α,3α-dihydroxyurs-12-en-28-oic acid	A. eriantha [7]	Roots
32	2α,3β,19α-Trihydroxyurs-12-en-23,28-dioic,acid-23-methylester	A. chinensis Radix [50]	Roots
33	3β-Hydroxy-13,28-epoxyurs-11-en-3-ol	A. kolomikta [51]	Rhizomes
34	28-Norurs-12-en-3β,17β-diol	A. kolomikta [51]	Rhizomes
35	Triptohypol E	A. kolomikta [51]	Rhizomes
36	Neoilexonol	A. kolomikta [51]	Rhizomes
37	11α-Methoxyurs-12-ene-3β,12-diol	A. arguta [34]	Leaves
38	Ilelatifol A	A. arguta [34]	Leaves
39	(2α,3β)-2,3,23-Trihydroxyurs-13(18)-en-28-oic acid	A. chinensis Planch [52]	Roots
40	Fupenzic acid	A. chinensis [25]	Root bark	Antiviral (in vitro) [25]
41	Nrsolaldehyde	A. arguta [26]	Stems
42	α-Amyrin	A. arguta [26]	Stems
43	Uvaol	A. arguta [26]	Stems	Anti-inflammatory (in vivo) [27] Anticancer (in vitro) [28] Wound healing (in vivo) [29]
44	Pseudotaraxasterol	A. chinensis Planch [19]	Roots
45	2α,3α,24-Trihydroxyurs-11-en-13,28-olide	A. polygama [23]	Fruit galls
46	2α,3β-Dihydroxyurs-12-en-28,30-olide	A. chinensis [30]	Roots
47	2α,3β,24-Trihydroxyurs-12-en-28,30-olide	A. chinensis [30]	Roots
48	Ehretiolide	A. kolomikta [51]	Rhizomes
49	3β-Acetoxyurs-11-en-28-oic 13(28)-lactone	A. kolomikta [51]	Rhizomes
50	3β-Hydroxyurs-12,18-dien-28-oic acid	A. chinensis [30]	Roots
51	(2α,3β,4α)-2,3-Dihydroxy-24-norursa-12,18-dien-28-oic acid	A. valvata Dunn [47]	Roots
52	2α,3α,23-Trihydroxy-12,20(30)-ursadien-28-oic acid	A. polygama [18] A. deliciosa [31]	Fruit galls Peels	Antifungal (in vitro) [31]
53	2α,3β,23-Trihydroxy-12,20(30)-ursadien-28-oic acid	A. deliciosa [31]	Peels	Antifungal (in vitro) [31]
54	2α,3α,24-Trihydroxy-12,20(30)-ursadien-28-oic acid	A. deliciosa [ 31]	Peels	Antifungal (in vitro) [31]
55	2α,3α,23,24-Tetrahydroxyursa-12,20(30)-dien-28-oic acid	A. chinensis Planch [32]	Roots	Anti-tumor (in vitro) [32]
56	3β-Trans-p-coumaroyloxy-2α,24-dihydroxy-urs-12- en-28-oic acid	A. polygama [23]	Fruit galls
57	3-O-Trans-p-coumaroyl tormentic acid	A. chinensis Radix [50]	Roots
58	3-O-Cis-p-coumaroyl tormentic acid	A. chinensis Radix [50]	Roots
59	3-O-Trans-p-coumaroylasiatic acid	A. polygama [18]	Fruit galls
60	23-O-Trans-p-coumaroylasiatic acid	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
61	Actiniargupene E	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
62	Actiniargupene F	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
63	Actiniargupene G	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
64	3-O-Trans-p-coumaroyl actinidic acid	A. arguta [13] A. arguta [34]	Roots Leaves
65	3-O-Cis-p-coumaroylactinidic acid	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
66	Actiniargupene A	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
67	Actiniargupene B	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
68	Actiniargupene C	A. arguta [34]	Leaves	Inhibiting α-glucosidase (in vitro) [34]
69	(+)-Tormentoside	A. arguta [53]	Roots
70	(+)-Euscaphic acid-28-O-β-d-glucopyranoside	A. arguta [53]	Roots
71	2α,3α,19α,24-Tetrahydroxyurs-12-en-28-oic acid 28-O-β-d-glucopyranoside	A. chinensis Planch [19]	Roots	Inhibiting SKVO3 and TPC-1 cancer cells lines (in vitro) [42]
72	2α,3β,19α,23-Tetrahydroxyurs-12-en-28-oic acid 28-O-β-d-glucopyranoside	A. chinensis Radix [50]	Roots
73	2α,3β,19α,23,24-Pentahydroxyurs-12-en-28-oic acid-28-O-β-d-glucopyranoside	A. rufa [35]	Roots
74	(2β,3α)-2,3,20,23,24,30-Hexahydroxyurs-12-en-28-oic acid O-β-d-glucopyranosyl ester	A. valvata Dunn [22]	Roots	Against BEL-7402 and SMMC-7721 tumor cells lines (in vitro) [22]
75	2α,3β,23,30-Tetrahydroxyurs-12,18-diene- 28-oic acid O-β-d-glucopyranosyl ester	A. valvata Dunn [36]	Roots	Against BEL-7402 and SMMC-7721 tumor cells lines (in vitro) [36]
76	30-O-β-d-Glucopyranosyloxy-2α,3α,24- trihydroxyurs-12,18-diene-28-oic acid O-β-d-glucopyranosyl ester	A. valvata Dunn [36]	Roots	Against BEL-7402 and SMMC-7721 tumor cells lines (in vitro) [36]

Compounds 2‒7 are ursane triterpenoids featuring with two hydroxyl groups. Compound 3 (2α-Hydroxyursolic acid) was tested for its antiproliferative activity and cytotoxicity in MDA-MB-231 human breast cancer cells through the methylene blue assay. It significantly down-regulated expressions of TRAF2, PCNA, cyclin D1, and CDK4 and up-regulated the expressions of p-ASK1, p-p38, p-p53, and p-21. Furthermore, it induced apoptosis in MDA-MB-231 cell by significantly increasing the Bax/Bcl-2 ratio and inducing the cleaved caspase-3 [12]. Compound 4 exhibited inhibitory activity on pancreatic lipase with an IC₅₀ value of 20.42 ± 0.95 μM [13]. It also showed cytotoxicity to human lung adenocarcinoma (A549), ovarian cancer (SK-OV-3), skin melanoma (SK-MEL-2), and colon cancer (HCT-15) cell lines with IC₅₀ values ranging from 11.96 to 14.11 μM [14–17].

Compounds 7‒14 are trihydroxy-ursolic acid derivatives. In early 1992, Sashida et al. reported the isolation of 8‒10. Compounds 8 and 9 were evaluated for their cytotoxicity against A549 cells, LOVO cells, and HepG2 cells with IC₅₀ values of 32.9, 31.6, 35.7 μg/mL respectively for 8 and 34.6, 13.9, 34.5 μg/mL respectively for 9 [18, 19]. Compounds 17‒26 are ursolic acids with four or five hydroxy groups. Xu et al. reported 17 from roots of A. valvata, this compound exhibited weak cytotoxicity against A549, LOVO and HepG2 cell lines with IC₅₀ values of above 100 μg/mL [20]. 2α,3α,19α,24-Tetrahydroxyurs-12-en-28-oic acid 20 was separated from the leaves of A. valvata which showed cytotoxicity against PLC, Hep3B, HepG2, HeLa, SW480, MCF-7 and Bel7402 in vitro [21]. A new polyoxygenated triterpenoid (2β,3α,6α)-2,3,6,20,23,30-hexahydroxyurs-12-en-28-oic acid 26 was obtained from the roots of A. valvata DUNN, it exhibited moderate cytotoxic activity against BEL-7402 and SMMC-7721 tumor cell lines in vitro [22].

Compound 30 (3β-O-acetylursolic acid) was isolated from the fruit galls of A. polygama and the structure was elucidated on the basis of chemical and spectral evidence. It was reported to be a mixed-type protein tyrosine phosphatase 1B (PTP1B) inhibitor with an IC₅₀ value of 4.8 ± 0.5 μΜ [23, 24]. Isolation of the antiviral active ingredient of A. chinensis root bark gave fupenzic acid 40, which showed moderate inactivity under the concentration of 100 μg/mL [25]. Callus tissue from the stems of A. arguta (Actinidiaceae) produced three ursane-type triterpenes including ursolaldehyde 41, α-amyrin 42, and uvaol 43 [26]. Of them, compound 43 showed anti-inflammatory, anticancer, and wound healing activities [27–29]. Anti-inflammatory properties of 43 on DSS-induced colitis and LPS-stimulated macrophages have been explored detailly and completely. It showed excellent potential of NO production inhibition. It could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice. What’s more, studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-inflammatory cytokines and mediators. These results indicating that uvaol is a prospective anti-inflammatory agent for colonic inflammation [27]. Guided by the hepatoprotective activity, the phytochemical study on the roots of A. chinensis led to the isolation of two new compounds 2α,3β-dihydroxyurs-12-en-28,30-olide 46, 2α,3β,24-trihydroxyurs-12-en-28,30-olide 47 and 3β-hydroxyurs-12,18-dien-28-oic acid 50 [30]. Compounds 52‒54 showed antifungal activity against C. musae at 3 μg/mL [31]. A new compound 2α,3α,23,24 -tetrahydroxyursa-12,20(30)-dien-28-oic acid 55 was isolated from the roots of A. chinensis Planch. It exhibited moderate antitumor activities against five human cancer cell lines (HepG2, A549, MCF-7, SK-OV-3, and HeLa) with IC₅₀ values of 19.62 ± 0.81, 18.86 ± 1.56, 45.94 ± 3.62, 62.41 ± 2.29, and 28.74 ± 1.07 μM, respectively [32].

Compounds 59‒63 are actinidic acid derivatives with a phenylpropanoid unit that were identified as 3-O-trans-p-coumaroylasiatic acid 59, 23-O-trans-p-coumaroylasiatic acid 60, actiniargupene E 61, actiniargupene F 62, and actiniargupene G 63 from the leaves of A. arguta. All the compounds showed inhibitory effects on α-glucosidase activity. Among them compound 59 showed most potentially inhibitory activity on α-glucosidase with an IC₅₀ of 81.3 ± 2.7 μM, equal to that of the positive control (acarbose, 72.8 ± 3.1 μM) [33]. The structure–activity relationship suggested that triterpenoids with a phenylpropanoid moiety exhibited more potent effects than those without such a unit [34]. Compound 71 showed potent cytotoxic activity against human SKVO3 and TPC-1 cancer cell lines with IC₅₀ values of 10.99 and 14.34 μM, respectively [19, 35]. Compound 74 exhibited moderate cytotoxic activity against BEL-7402 and SMMC-7721 tumor cell lines [22]. Compounds 75 and 76 were isolated from roots of A. valvata Dunn. They exhibited moderate cytotoxic activity in vitro against BEL-7402 and SMMC-7721 tumor cell line [36].

Oleanane Triterpenoids

Oleanane-type triterpenoids also possessed a 6/6/6/6/6 pentacyclic carbon skeleton. Unlike ursane triterpenes, oleanane-type triterpenoids have two methyl groups at the C-20 position instead of each one at the C-19 and C-20, respectively. So far, a total of 24 oleanane-type triterpenoids have been identified from Actinidia plants (77‒100, Fig. 3, Table 2). The most representative compound is oleanolic acid 77. It was found from callus tissue from the stems of A. arguta, together with 2α,3β-dihydroxyolean-12-en-28-oic acid 78 [26]. Oleanolic acid 77 is abundant in nature and exhibits a wide range of biological activities including anti-inflammatory [54], anti-hypertension [55], anti-tumor [56, 57], neuroprotection [58], and anti-cholesterol activities [59]. Oleanolic acid was performed to test the effect on apoptosis and autophagy of SMMC-7721 Hepatoma cells. It can significantly inhibit the growth of liver cancer SMMC-7721 cells and induce autophagy and apoptosis [57]. Compound 78 also showed anti-tumor and anti-inflammatory activities [60, 61]. Lim et al. have demonstrated that 78 showed very strong anti-tumor-promoting activity with an IC₅₀ of 0.1 mg/mL [60].

Fig. 3.

Structures of oleanane triterpenoids 77‒100 from Actinidia plants

Table 2.

Information of oleanane triterpenoids from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
77	Oleanolic acid	A. arguta [26]	Stems	Anti-inflammatory (in vitro) [54] Anti-hypertension (in vivo) [55] Anti-tumor (in vitro) [56, 57] Neuroprotection(in vitro) [58] Anti-cholesterol(in vitro) [59]
78	2α,3β-Dihydroxyolean-12-en-28-oic acid	A. arguta [26]	Stems
79	2α,3α-Dihydroxyolean-12-en-28-oic acid	A. chinensis Planch [63]	Fruits
80	2α,3β,23-Trihydroxyolean-12-en-28-oic acid	A. deliciosa [31]	Peels	Antifungal (in vitro) [31]
81	2α,3α,24-Trihydroxyolean-12-en-28-oic acid	A. deliciosa [31]	Peels	Antifungal (in vitro) [31]
82	3β-O-Acetyloleanolic acid	A. arguta [64] A. chinensis [45]	Stems Roots	Anti-angiogenesis (in vitro) [45]
83	2α,3β,19-Trihydroxyolean-12-en-28-oic acid	A. chinensis [45]	Roots	Anti-angiogenesis (in vitro) [45]
84	(3β,4α,16α)-3,16,23-Trihydroxyolean-12- en-28-oic acid	A. valvata Dunn [47]	Roots
85	(2β, 3β, 4α, 16α)-2, 3, 16, 23-Tetrahydroxyolean-12-en-28-oic acid	A. valvata Dunn [47]	Roots
86	2α,3β,19α,23-Tetrahydroxyoleanolic acid	A. deliciosa [65]	Roots
87	3β,23,24-Trihydroxyl-12-oleanen-28-oic acid	A. eriantha Benth [62]	Roots	Anti-angiogenesis (in vitro) [62]
88	9(11),12-Diene-30-oic acid	A. chinensis [25]	Roots bark	Anti-viral (in vitro) [25]
89	12α-Chloro-2α,3β,13β,23-tetrahydroxyolean-28-oic acid-13-lactone	A. chinensis Planch [19]	Roots	Anti-catalysis (in vitro) [43]
90	β-Amyrin	A. arguta [26]	Stems
91	Erythrodiol	A. kolomikta [51]	Dried rhizomes
92	12-Oleanene 2α,3α,24-triol	A. macrosperma [66]	Roots
93	3β-(2-Carboxybenzoyloxy) oleanolic acid	A. chinensis [25]	Root bark	Anti-phytoviral (in vitro) [25]
94	Spathodic acid-28-O-β-d-glucopyranoside	A. chinensis [25]	Root bark	Anti-phytoviral (in vitro) [25]
95	Oleanolic acid-23-O-β-d-glucopyranoside	A. eriantha Benth [62]	Roots	Anti-angiogenesis (in vitro) [62]
96	2α,3β,19α,23,24-Pentahydroxy-12-oleanen 28-oic acid 28-β-d-glucopyranosyl	A. chinensis Radix [50]	Roots
97	3-O-β-d-Glucopyranosyl-2α,3β,6β,19α,21β,23-hexahydroxylolean-12-en-28-oic acid	A. kolomikta [67]	Leaves
98	3β,23-Dihydroxy-30-norolean-12,20(29)- dien-28-oic acid	A. chinensis Radix [50]	Roots
99	3β,23-Dihydroxy-1-oxo-30-norolean- 12,20(29)-dien-28-oic acid	A. chinensis Radix [50]	Roots
100	2α,3α,23,24-Tetrahydroxy-30-norolean- 12,20(29)-dien-28-oic acid	A. chinensis Radix [50]	Roots

Bioassay- and ¹H NMR-guided fractionation of the methanol extract afforded two oleanolic acids of 2α,3β,23-trihydroxyolean-12-en-28-oic acid 80 and 2α,3α,24-trihydroxyolean-12-en-28-oic acid 81, showing antifungal activity against C. musae at 3 μg/mL [31]. The EtOAc extract of the roots of A. eriantha Benth exhibited potent growth inhibitory activity against SGC7901 cells, CNE2 cells and HUVECs cells. From which, compound 87 (3β,23,24-trihydroxyl-12-oleanen-28-oic acid) was identified [62]. Compound 88 was extracted from the roots bark of A. chinensis, which showed anti-viral activity [25]. A new triterpenoid 12α-chloro-2α,3β,13β,23 -tetrahydroxyolean-28-oic acid-13-lactone 89 was extracted from the roots of A. chinensis Planch (Actinidiaceae). It was tested for cytochrome P450 (CYPs) enzyme inhibitory activity in later years, which could significantly inhibit the catalytic activities of CYP3A4 to < 10% of its control activities [19, 52].

3β-(2-Carboxybenzoyloxy) oleanolic acid 93 and spathodic acid-28-O-β-d-glucopyranoside 94 were extracted from the root bark of A. chinensis. The anti-phytoviral activity test indicated that 94 showed potent activity on TMV, and CMV with inactivation effect of 46.67 ± 1.05, and 45.79 ± 2.23 (100 mg/L), compared to ningnanmycin with inactivation effect of 30.15 ± 1.16 and 27.18 ± 1.02 (100 mg/L) respectively [25]. 3β,23-Dihydroxy- -30-norolean-12,20(29)-dien-28-oic acid 98, 3β,23-dihydroxy-1-oxo-30-norolean-12,20(29)-dien-28-oic acid 99, and 2α,3α,23,24-tetrahydroxy-30-norolean-12,20(29)-dien-28-oicacid 100 are three one-carbon-degraded oleanane triterpenoids that were identified from A. chinensis Radix for the first time [50].

Lupane Triterpenoids

Lupane triterpenoids possess a 6/6/6/6/5-fused carbon skeleton. Compared with ursane and oleanane triterpenoids, the number of lupane triterpenoids in the Actinidia plants is much smaller, only four related compounds have been identified (101‒104, Fig. 4, Table 3). Three of them (101‒103) were identified from the rhizomes of A. kolomikta [51]. Betulinic acid 101 is one of the most representative compound of lupane triterpenes, it has been extensively studied in recent years based on the wide biological activities including anti-inflammatory, antitumor, anti-HIV, anti-diabetic and antimalarial activities [68–73]. Much attention as a molecular target about protein tyrosine phosphatase 1B had been paid to the treatment of insulin resistance diseases because of its critical roles in negatively regulating insulin- and leptin-signaling cascades. Betulinic acid showed significant PTP1B inhibitory activity, with IC₅₀ values of 3.5 μM [24].

Fig. 4.

Structures of lupane triterpenoids 101‒104 from Actinidia plants

Table 3.

Information of lupane triterpenoids from Actinidia Plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
101	Betulinic acid	A. kolomikta [51]	Rhizomes	Anti-inflammatory (in vitro) [68] Antitumor(in vitro) [69] Anti-HIV(in vitro) [72] Anti-diabetic(in vivo) [73]
102	Betulin	A. kolomikta [51]	Rhizomes	Anti-tumor(in vitro) [74–76]
103	Diospyrolide	A. kolomikta [51]	Rhizomes
104	Lupa-12,20(30)-diene-2β,3β,28-triol	A. deliciosa [48]	Roots

Other Terpenoids

A total of 19 other terpenoids including iridoids, diterpenoids, and their glycosides have been found from Actinidia plants (105 − 123, Fig. 5, Table 4). None of these compounds have good biological activities, only compound 120 showed certain anti-angiogenesis activity [77].

Fig. 5.

Structures of other terpenoids 105‒123 from Actinidia plants

Table 4.

Information of other triterpenoids from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
105	Dihydroepinepetalactone	A. polygama [78]	Fresh fruits
106	Isodihydroepinepetalactone	A. polygama [78]	Fresh fruits
107	Isoepiiridomyrmecin	A. polygama [78]	Fresh fruits
108	Isoneonepetalactone	A. polygama [78]	Fresh fruits
109	Dehydroiridomyrmecin	A. polygama [78]	Fresh fruits
110	Isodehydroiridomyrmecin	A. polygama [78]	Fresh fruits
111	Actinidialactone	A. polygama [78]	Fresh fruits
112	Isoactinidialactone	A. polygama [78]	Fresh fruits
113	Neonepetalactone	A. polygama [78]	Fresh fruits
114	Dihydronepetalactone	A. polygama [78]	Fresh fruits
115	Isodihydronepetalactone	A. polygama [78]	Fresh fruits
116	Iridomyrmecin	A. polygama [78]	Fresh fruits
117	Isoiridomyrmecin	A. polygama [78]	Fresh fruits
118	Matatabiether	A. polygama [79]	Leaves and galls
119	(R)-1,2,6,7,8,9-Hexahydro-10-hydroxy-1,6,6-trimethylphenanthro[1,2-b]furan-5,11-dione	A. valvataDunn [47]	Roots
120	(6R,7E,9S)-6,9-Hydroxy-megastigman-4,7-dien-3-one-9-O-β-glucopyranoside	A. eriantha Benth [62]	Roots	Anti-angiogenesis (in vitro) [62]
121	Kiwiionoside	A. chinensis [80]	Fresh leaves
122	Iridodialo-β-d-gentiobioside	A. polygama [77]	Leaves
123	Dehydroiridodialo-β-d-gentiobioside	A. polygama [77]	Leaves

Steroids

β-Sitosterol 124 is a very normal phytosterol almost distributed in all plants. Eight phytosterols have been obtained from the Actinidia plants (124‒131, Fig. 6, Table 5). Pharmacological studies on these steroids have demonstrated that β-sitosterol showed various bioactivities including anti-inflammatory, anti-cancer, antimicrobial and anti-diabetic properties [81–88]. A study suggested that β-sitosterol may serve as a potential therapeutic in the treatment of acute organ damages [82].

Fig. 6.

Structures of steroids 124‒138 from Actinidia plants

Table 5.

Information of steroids from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
124	β-Sitosterol	A. eriantha [7]	Roots	Anti-inflammatory (In vivo) [84] Anticancer (in vitro) [85] Anti-microbial (in vitro) [86] Anti-diabetic (In vivo) [88]
125	Stigmast-3,6-dione	A. chrysantha [42]	Roots
126	Masterol	A. deliciosa [89]	Peels
127	Stigmast-7-en-3β-ol	A. deliciosa [89]	Peels
128	3β-Hydroxystigmast-5-en-7-one	A. chinensis Planch [52]	Roots
129	Sitostanetriol	A. kolomikta [51]	Dried rhizomes
130	(24R)-Stigmast-4-en-3-one	A. kolomikta [51]	Dried rhizomes
131	Stigmasterol	A. arguta [26]	Stems	Anti-inflammatory (in vitro) [90]
132	Daucosterol	A. eriantha [40] A. chinensis [44]	Roots Roots
133	Campesterol	A. deliciosa [89]	Peels
134	Ergosterol	A. deliciosa [89]	Peels
135	Ergost-22-en-3-ol	A. deliciosa [89]	Peels
136	5,7,14,22-Ergostatetraen-3β-ol	A. deliciosa [89]	Peels
137	5,8-Epidioxyergosta-6,22-dien-3β-ol	A. kolomikta [51]	Dried rhizomes
138	24-Methylene-pollinastanol	A. kolomikta [51]	Dried rhizomes

In addition to phytosterols, seven normal ergosterols (132‒137, Fig. 6, Table 5) were obtained from peel or rhizomes of kiwifruit plants. It is well known that ergosterols should be fungal products. Compounds 132‒137 may be produced by fungal infected kiwifruit plants.

Phenols

Catechins and Epicatechins

A total of 16 related compounds (139‒154) have been obtained from kiwifruit plants (Fig. 7, Table 6). Compounds 148 and 149 possessed a novel structure featuring with a pyrrolidin-2-one substituent at C-6 and C-8, respectively. Compounds 152 and 153 were two sulfur-containing catechins that was rare in nature. Pharmacological studies have revealed that (+)-catechin 139 and (−)-epi-catechin 140 showed nitric oxide inhibitory activity in LPS stimulated RAW 264.7 cell with IC₅₀ values of 26.61 and 25.30 μg/mL, respectively [53, 91]. Compound 147 showed moderate radical scavenging and antioxidant capabilities by measuring their capacity to scavenge DPPH and anion superoxide radical and to reduce a Mo(VI) salt [89]. Two new flavan-3-ols, 6-(2-pyrrolidinone-5-yl)-(−)-epicatechin 148 and 8-(2-pyrrolidinone-5-yl)-(−)-epicatechin 149, as well as proanthocyanidin B-4 150, were isolated from an EtOAc-soluble extract of the roots of A. arguta. The isolates were tested in vitro for their inhibitory activity on the formation of advanced glycation end products (AGEs). All of them exhibited significant inhibitory activity against AGEs formation with IC₅₀ values ranging from 10.1 to 125.2 μM [92].

Fig. 7.

Structures of catechins and epicatechins 139‒154 from Actinidia plants

Table 6.

Information of catechins and epicatechins from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
139	(+)-Catechin	A. arguta [41]	Roots	Anti-DPPH radical and inhibiting nitric oxide (in vitro) [57] Anti-bacteria (in vitro) [93]
140	(−)-Epi-catechin	A. arguta [41]	Roots	Anti-DPPH radical and inhibiting nitric oxide (in vitro) [57]
141	(+)-Afzelechin	A. chinensis Planch [94]	Roots
142	(−)-Epi-afzelechin	A. chinensis Planch [94]	Roots
143	(+)-Catechin(4α → 8)(+)-catechin	A. chinensis Planch [94]	Roots
144	(−)-Epi-catechin(4β → 8)(−)-epi-catechin	A. chinensis Planch [94]	Roots
145	(+)-Afzelechin(4α → 8) (+)-afzelechin	A. chinensis Planch [94]	Roots
146	(−)-Epi-afzelechin(4β → 8)(−)-epi-afzelechin	A. chinensis Planch [94]	Roots
147	Gallocatechin	A. deliciosa [89]	Peels	Radical scavenging and antioxidant (in vitro) [89]
148	6-(2-Pyrrolidinone-5-yl)-(−)-epicatechin	A. arguta [92]	Roots	Against advanced glycation-end (in vitro) [92]
149	8-(2-Pyrrolidinone-5-yl)-(−)-epicatechin	A. arguta [92]	Roots	Against advanced glycation-end (in vitro) [92]
150	Proanthocyanidin B-4	A. arguta [92]	Roots	Against advanced glycation-end (in vitro) [92]
151	(−)-Epi-Catechin-5-O-β-D-glucopyranoside	A. arguta [92]	Roots	Against advanced glycation-end (in vitro) [92]
152	Benzylthio-(−)-epicatechol	A. chinensis [95]	Vegetative parts
153	4′-Benzylthioprocyanidol B2	A. chinensis [95]	Vegetative parts
154	Procyanidol C1	A. chinensis [95]	Vegetative parts

Flavones, Isoflavones, and Flavonols

A total of 48 flavone derivatives have been identified from kiwifruit plants, most of which are glycosides (155‒202, Fig. 8, Table 7). Pharmacological studies indicated that these compounds, particularly kaempferol and its derivative, had a wide range of biological activities including antiproliferation, antioxidation, anti-inflammation, anticancer, anti-free radical, and neuroprotection activities [96–99]. Kaempferol 157 was found to prevent neurotoxicity by several ways which was able to completely block N-methyl-D-aspartate (NMDA)-induced neuronal toxicity and potently inhibited MAO (monoamine oxidase) with the IC₅₀ of 0.8 μM [99]. Two novel flavonoids 171 and 172 were separated from the leaves of A. valvata Dunn. They exhibited dose-dependent activity in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals, superoxide anion radicals, and hydroxyl radicals, and inhibited lipid peroxidation of mouse liver homogenate in vitro [100]. Compounds 178 [101] and 179 [102] were two new compounds obtained from the leaves of A. kolomikta. The latter was screened for its protective effect on human erythrocytes against AAPH-induced hemolysis, which could slow the hemolysis induced by AAPH [102]. Eerduna et al. evaluated the effects of compound 182 on acute myocardial infarction in rats, the groups treated with 182 showed a dose-dependent reduction in myocardial infarct size model, markedly inhibited the elevation of the activity of creatine kinase, troponin T level, and the content of malondialdehyde induced by AMI [103]. Compound 182 also showed a capacity to increase the activities of superoxide dismutase, catalase, and endothelial nitric oxide synthase [104]. Lim et al. tested the DPPH radical scavenging activity and nitric oxide production inhibitory activity in IFN-γ, LPS stimulated RAW 264.7 cell of quercetin 185, quercetin-3-O-β-d-glucoside 186, and quercetin 3-O-β-d-galactoside 193 with IC₅₀ value of 20.41, 18.23, and 30.46 μg/mL, respectively [91].

Fig. 8.

Structures of flavones, isoflavones, and flavonols 155‒202 from Actinidia plants

Table 7.

Information of flavones, isoflavones, and flavonols from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
155	7,4′-Dihydroxyflavone	A. chinensis Planch [105]	Roots	Anti-inflammatory (in vitro) [106]
156	Formononetin	A. chinensis Planch [105]	Roots
157	Kaempferol	A. deliciosa [107]	Leaves	Antiproliferation human tumor cell (in vitro) [96] Antioxidant and anti-inflammatory (in vitro) [97] Anticancer (in vitro) [98] Neuroprotection (in vitro) [99]
158	6-C-Glucose-5,7,3′,4′-tetrahydroxy flavone	A. arguta [108]	Roots
159	6-C-Glucose-5,7,4′-trihydroxy flavone	A. arguta [108]	Roots
160	6-C-Glycopyranosyl-8-C-xyloeyl apigenin	A. polygama [109]	Leaves
161	Vicenin-I	A. polygama [110]	Aerial Parts
162	Kaempferol 3-O-glucoside	A. deliciosa [107]	Leaves
163	Kaempferol 3-O-rhamnoside	A. deliciosa [107]	Leaves
164	Kaempferol 7-O-glucoside	A. deliciosa [107]	Leaves
165	Kaempferol 3-O-β-d-galactopyranoside	A. polygama [109]	Leaves
166	Kaempferol-7-O-β-l-rhamnoside	A. kolomikta [102]	Leaves
167	Kaempnferol-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside	A. polygama [109]	Leaves
168	Kaempferol 3-O-rutinoside	A. deliciosa [107]	Leaves
169	Kaempferol-7-O-(4″-O-acetylrhamnosyl)-3-O-rutinoside	A. kolomikta [111]	Leaves
170	Kaempferol-3-O-α-l-rhamnopyranosyl- (1 → 3)-α-l-rhamnopyranosyl- (1 → 6)-β-d-galactopyranoside	A. polygama [109]	Leaves
171	Kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 3) (2,4-di-O-acetyl-α-l-rhamnopyranosyl) (1 → 6) β-d-galactopyranoside	A. valvata Dunn [100]	Leaves	Anti-free radical (in vitro) [100]
172	Kaempferol 3-O-α-l-rhamnopyranosyl (1 → 3) (4-O-acetyl-α-l-rhamnopyranosyl) (1 → 6) β-D-galactopyranoside	A. valvata Dunn [100]	Leaves	Anti-free radical (in vitro) [100]
173	Kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 3)- (4-O-acetyl)-O-α-l-rhamnopyranosyl-(1 → 6)- O-acetyl)-O-β-d-galactopyranoside]	A. polygama [110]	Aerial parts
174	Kaempferol 3-O-[α-rhamnopyranosyl-(1 → 4)- rhamnopyranosyl-(1 → 6)-β-galactopyranoside]	A. deliciosa [112]	Leaves
175	Kaempferol 3-O-[α-rhamnopyranosyl-(1 → 4)- rhamnopyranosyl-(1 → 6)-β-glucopyranoside]	A. deliciosa [112]	Leaves
176	Kaempferol 3-O-[α-rhamnopyranosyl-(1 → 4)-3‴ -O-acetyl-α-rhamnopyranosyl-(1 → 6)-β-galactop-yranoside]	A. deliciosa [112]	Leaves
177	Kaempferol-7-O-α-l-rhamnosyl-3-O-rutinoside	A. kolomikta [102]	Leaves
178	Kaempferide-7-O-rhamnoside	A. kolomikta [101]	Leaves
179	Kaempferide-7-O-(4″-O-acetyl)-α-l-rhamnoside	A. kolomikta [102]	Leaves	Against AAPH-​induced hemolysis (in vitro) [102]
180	Kaempferide-3-O-rutinoside	A. kolomikta [113]	Leaves	Anti-free radical (in vitro) [113]
181	Kaempferide-7-O-(4″-O-acetyl-rhamnosyl)-3-O-glucoside	A. kolomikta [113]	Leaves	Anti-free radical (in vitro) [113]
182	Kaempferide-7-O-(4″-O-acetyl-rhamnosyl)-3-O-rutinoside	A. kolomikta [113]	Leaves	Anti-free radical (in vitro) [113] Reducing myocardial infarction (in vivo) [104]
183	Kaempferide-7-O-rhamnosyl-3-O-rutinoside	A. kolomikta [101]	Leaves
184	Kaempferide-7-O-(3″-O-acetylrhamnosyl)-3-O-rutinoside	A. kolomikta [111]	Leaves
185	Quercetin	A. deliciosa [107]	Leaves
186	Quercetin-3-O-β-d-glucoside	A. deliciosa [107]	Leaves
187	Quercetin 3-O-rhamnoside	A. deliciosa [107]	Leaves
188	Quercetin 7-O-glucoside	A. deliciosa [107]	Leaves
189	Quercetin 3-O-xyloside	A. deliciosa [107]	Leaves
190	Quercetin 3-O-arabinoside	A. deliciosa [107]	Leaves
191	Quercetin 3-O-rutinoside	A. deliciosa [107]	Leaves
192	Quercetin 3-O-rhamnoside 7-O-glucoside	A. deliciosa [107]	Leaves
193	Quercetin 3-O-β-d-galactoside	A. polygama [110]	Aerial parts	Anti-DPPH radical and nitric oxide production (in vitro) [110]
194	Quercetin 3-O-β-d-glucofuranoside (isoquercitrin)	A. chinensis Planch [114]
195	Quercetin 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside	A. arguta [108]	Roots
196	Isorhamnetin-3-O-β-d-glucoside	A. kolomikta [102]	Leaves
197	Quercetin3-O-[α-rhamnopyranosyl-(1 → 4) -rhamnopyranosyl-(1 → 6)-β-galactopyranoside	A. deliciosa [112]	Leaves
198	Quercetin 3-O-β-d-[2G-O-β-d-xylopyranosyl-6G-O-α-l-rhamnopyranosyl] glucopyranoside	A. arguta [115]	Leaves
199	Quercetin 3-O-β-d-xylopyranosyl- (1 → 2)-O-β-d-glucopyranoside	A. arguta [115]	Leaves
200	7-O-[β-d-Pyranrhamnose-(1 → 6)-β-D-pyran glucose]-5,3′-dihydroxy-4′-methoxy two dihydrogen flavone	A. arguta [108]	Roots
201	4′-Methoxyl-quercetin-7-(4″-O-acetylrhamnosyl)-3-O-β-D-glucopyranoside	A. kolomikta [111]	Leaves
202	4′-Methoxyl-quercetin-7-(4″-O-acetylrhamnosyl)-3-O-rutinoside	A. kolomikta [111]	Leaves

Xanthones

Three xanthones were isolated from n-butyl alcohol fraction of A. arguta (Sieb. & Zucc) Planch. ex Miq and identified as 2-β-d-glu-1,3,7-trihydrogen xanthone 203, 7-O-[β-d-xylose-(1 → 6)-β-d-glucopyranoside]-1,8-dihydroxy-3-methoxy xanthone 204, and 1-O-[β-d-xylose-(1 → 6)-β-d-glucopyranside] -8-hydroxy-3,7-dimethoxy xanthone 205 (Fig. 9, Table 8). They were isolated from this plant for the first time [108]. Compound 203 showed extensive biological activities, including inhibiting α-Glycosidase, NO production inhibition and NF-κB inhibition and PPAR activation [116, 117]. It has been demonstrated the inhibitory effects on NF-κB transcriptional activation in HepG2 cells stimulated with TNFα with an IC₅₀ value of 0.85 ± 0.07 μM, which was more potent than the positive control of sulfasalazine (IC₅₀ = 0.9 μM) [118].

Fig. 9.

Structures of xanthones, isoflavones, and flavonols 203‒219 from Actinidia plants

Table 8.

Information of xanthones, anthocyanins, and emodins from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
203	2-β-d-Glu-1,3,7-trihydrogen xanthone	A. arguta [108]	Roots	Inhibiting α-Glycosidase (in vitro) [116] NO inhibitory (in vitro) [117] NF-κB Inhibition and PPAR Activation (in vitro) [118]
204	7-O-[β-d-Xylose-(1 → 6)-β-d-glucopyranoside]-1,8-dihydroxy-3-methoxy xanthone	A. arguta [108]	Roots
205	1-O-[β-d-Xylose-(1 → 6)-β-d-glucopyranoside] -8-hydroxy-3,7-dimethoxy xanthone	A. arguta [108]	Roots
206	Delphinidin 3-galactoside	A. deliciosa [119]	Fruits	Antioxidation (in vitro) [135]
207	Cyanidin 3-galactoside	A. deliciosa [119]	Fruits
208	Cyanidin 3-glucoside	A. deliciosa [119]	Fruits	Anti-inflammatory (in vitro) [120, 121] Neuroprotective (in vivo) [122] Anti-cancer (in vitro) [123] Antioxidation (in vivo) [124]
209	Delphinidin 3-[2-(xylosyl)galactoside]	A. deliciosa [119]	Fruits
210	Cyanidin 3-[2-(xylosyl)galactoside]	A. deliciosa [119]	Fruits
211	Aloe-emodin	A. deliciosa [125]	Roots	Anti-inflammatory (in vitro) [126] Antifungal (in vitro) [127] Anticancer (in vitro) [128]
212	11-O-Acetyl-aloe-emodin	A. deliciosa [125]	Roots
213	Aloe-emodin 11-O-α-l-rhamnopyranoside	A. deliciosa [125]	Roots
214	Physcion (emodin-6-Me ether)	A. chinensis Planch [133]	Roots
215	Emodin (frangala-emodin)	A. chinensis Planch [133]	Roots	Anti-inflammatory (in vivo and in vitro) [129] Neuroprotection (in vitro) [130] Anti-cardiovascular (in vitro) [131] Inhibiting α-Glucosidase (in vitro) [132]
216	Questin (emodin-8-Me ether)	A. chinensis Planch [133]	Roots	Hepatoprotection (in vitro) [134]
217	Citreorosein (ω-hydroxyemodin)	A. chinensis Planch [133]	Roots
218	Emodic acid	A. chinensis Planch [133]	Roots
219	Emodin-8-β-d-glucoside	A. chinensis Planch [133]	Roots

Anthocyanins

Five anthocyanins were obtained from the flesh of larger fruit of A. deliciosa and A. chinensis and identified as delphinidin 3-galactoside 206, cyanidin 3-galactoside 207, cyanidin 3-glucoside 208, delphinidin 3-[2-(xylosyl)galactoside] 209, and cyanidin 3-[2-(xylosyl)galactoside] 210, respectively (Fig. 9, Table 8) [119]. Cyanidin 3-glucoside 208 exhibited a wide range of pharmacological activities including anti-inflammatory, neuroprotective, anti-cancer, and antioxidant activities [120–124].

Emodins

A total of nine emodin derivatives were obtained (211‒219, Fig. 9, Table 8). Three emodin constituents were isolated from EtOAc fraction of the roots of A. deliciosa for the first time, and their structures were identified to be aloe-emodin 211, 11-O-acetyl-aloe-emodin 212, and aloe-emodin 11-O-α-l-rhamno -pyranoside 213 [125]. Compound 211 exhibited intriguing biological activities including inflammatory, antifungal, and anticancer activity [126–128]. Lipoxygenases (LOXs) are potential treatment targets in a variety of inflammatory conditions, enzyme kinetics showed that aloe emodin inhibited lipoxygenase competitively with an IC₅₀ of 29.49 μM [126]. Compound 215 was reported to possess wide biological activities including anti-inflammatory, neuroprotection, anti-cardiovascular and α-glucosidase inhibitory activity [129–132]. It exhibited potent inhibition of α-glucosidase with an IC₅₀ value of 19 ± 1 μM and lower cytotoxicity to the Caco-2 cell line [132].

Phenylpropionic Acids

A total of 38 phenylpropionic acid derivatives have been identified from kiwifruit plants (220‒257. Fig. 10, Table 9), while most of them were glycosides or quinic acid derivatives. Phytochemical examination of the fruits of A. arguta led to the isolation of two organic acids including caffeic acid 220 and caffeoyl-β-d-glucopyranoside 221, which were tested for their nitric oxide production inhibitory activity in LPS-stimulated RAW 264.7 cells and DPPH radical scavenging activities. Compared with positive control (L-NMMA), they were potently reduced nitric oxide productions and showed anti-oxidative activities [135]. Nine succinic acid derivatives (228‒236), eleven quinic acid (245‒255) derivatives and two shikimic acid derivatives (256 and 257) were isolated from the fruits of A. arguta. The NF-κB transcriptional inhibitory activity of the compounds was evaluated using RAW 264.7 macrophages cells induced by lipopolysaccharide. Among the groups of different organic acid derivatives, the quinic acid derivatives inhibited NF-κB transcriptional activity with an IC₅₀ value of 4.0 μM [136].

Fig. 10.

Structures of phenylpropionic acids 220‒257 from Actinidia plants

Table 9.

Information of phenylpropionic acids from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
220	Caffeic acid	A. arguta [135]	Fruits	Anti-oxidation (in vitro) [135]
221	Caffeoyl-β-d-glucopyranoside	A. arguta [135]	Fruits	Anti-oxidation (in vitro) [135]
222	Trans-ferulic acid	A. polygama [110]	Aerial parts
223	Coumaric acid 4-O-glucoside	A. polygama [110]	Aerial parts
224	Trans-phydroxycinnamic acid	A. chinensis [137]	Roots
225	Caffeic 3-O-β-d-glucopyranoside acid	A. deliciosa [89]	Pulps
226	Caffeic 4-O-β-d-glucopyranoside acid	A. deliciosa [89]	Pulps
227	4,4′-Dihydroxyl-dihydrochalcone-2′-O-β-d-glucopyranoside	A. chinensis Plach [52]	Roots
228	Argutinoside A	A. arguta [136]	Fruits
229	Argutinoside B	A. arguta [136]	Fruits
230	Argutinoside C	A. arguta [136]	Fruits
231	Argutinoside D	A. arguta [136]	Fruits
232	Argutinoside E	A. arguta [136]	Fruits
233	Argutinoside F	A. arguta [136]	Fruits
234	Argutinoside G	A. arguta [136]	Fruits
235	Argutinoside H	A. arguta [136]	Fruits
236	Argutinoside I	A. arguta [136]	Fruits
237	Fertaric acid	A. arguta [138]	Fruits
238	Cryptochlorogenic acid	A. chinensis [137]	Roots
239	Neochlorogenic acid	A. chinensis [137]	Roots	Anti-inflammatory (in vitro) [139] Antibacteria and antioxidation (in vitro) [140]
240	3-O-Coumaroylquinic acid	A. chinensis [137]	Roots
241	Chlorogenic acid	A. deliciosa [89]	Pulp	Antitumor (in vitro) [141] Anti-inflammatory (in vitro) [142]
242	5- Trans-p-coumaroylmalic acid	A. chinensis Radix [50]	Roots
243	5- Cis-p-coumaroylquinic acid	A. chinensis Radix [50]	Roots
244	4-O- Cis-p-coumaroylquinic acid	A. chinensis Radix [50]	Roots
245	3-O-Trans-p-coumaroyl quinic acid methyl ester	A. arguta [136]	Fruits	Inhibiting NF-κB transcription (in vitro) [136]
246	3-O-Cis-p-coumaroyl quinic acid methyl ester	A. arguta [136]	Fruits
247	3-O-Trans-p-caffeoyl quinic acid methyl ester	A. arguta [136]	Fruits
248	5-O-Trans-p-coumaroyl quinic acid methyl ester	A. arguta [136]	Fruits
249	5-O-Cis-p-coumaroyl quinic acid methyl ester	A. arguta [136]	Fruits
250	5-O-Trans-p-caffeoyl quinic acid methyl ester	A. arguta [136]	Fruits
251	5-O-Cis-p-caffeoyl quinic acid methyl ester	A. arguta [136]	Fruits
252	3-O-Trans-p-caffeoyl quinic acid butyl ester	A. arguta [136]	Fruits
253	4-O-Trans-p-caffeoyl quinic acid butyl ester	A. arguta [136]	Fruits
254	5-O-Trans-p-coumaroyl quinic acid butyl ester	A. arguta [136]	Fruits
255	5-O-Trans-p-caffeoyl quinic acid butyl ester	A. arguta [136]	Fruits
256	3-O-Trans-p-coumaroyl shikimic acid	A. arguta [136]	Fruits
257	3-O-Cis-p-coumaroyl shikimic acid	A. arguta [136]	Fruits

Coumarins

Coumarins are rarely identified from kiwifruit plants, and only eleven members have been reported (258‒267, Fig. 11, Table 10). Umbelliferone 258 was obtained from the leaves of A. polygama (Sieb. et Zucc.) Miq [109]. A number of studies demonstrate the pharmacological properties of 258 including antitumor, anti-inflammatory, antioxidant, antidiabetic, and immunomodulatory activities [143–149]. It showed cytotoxicity against MCF-7 and MDA-MB-231 cell lines with IC₅₀ values of 15.56 and 10.31 μM, respectively [148]. Phytochemical examination of the fruits of A. arguta led to the isolation of esculetin 259 [135]. Two coumarins were isolated from the roots of A. deliciosa and identified as fraxetin 260 and isoscopoletin 261 [150]. Compound 260 showed potent inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) generation with an IC₅₀ value of 10.11 ± 0.47 µM [151]. Esculin 263 and fraxin 264 were characterized from the stems and fruits of A. deliciosa (kiwifruit) and A. chinensis [152]. Compound 264 showed inhibitory activity towards HepG2 with an IC₅₀ value of 14.71 μM [153].

Fig. 11.

Structures of coumarins 258‒268 from Actinidia plants

Table 10.

Information of coumarins from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
258	Umbelliferone	A. polygama [109]	Leaves	Anti-tumor (in vitro) [143] Anti-inflammatory (in vitro) [144] Antioxidant (in vitro) [149] Antidiabetic (in vitro and in vivo) [146] Immunomodulatory(in vitro) [148]
259	Esculetin	A. arguta [135]	Fruits	Anti-tumor (in vitro) [154] Anti-oxidant and anti-inflammatory (in vivo) [155]
260	Fraxetin	A. deliciosa [150]	Roots	Anti-inflammatory (in vitro) [151] Anti-tumor (in vitro) [156]
261	Isoscopoletin	A. deliciosa [150]	Roots	Anti-inflammatory [151]
262	Isofraxoside	A. chinensis [137]	Roots
263	Esculin	A. deliciosa [152]	Stems
264	Fraxin	A. chinensis [152]	Fruits	Anti-inflammatory (in vivo) [157] Antitumor (in vitro) [153]
265	5-Hydroxy-6-methoxy-7-O-β-d- glycopyranosylcoumarin	A. chinensis Radix [50]	Roots
266	6′-Acetoxy-8-β-d-glucopyranosyloxy-7- hydroxy-6-methoxy-coumarin	A. chinensis Radix [50]	Roots
267	6-Hydroxy7-(β-d-glucopyranosyloxy) coumarin	A. deliciosa [89]	Peels
268	6,8-Dimethoxy-7-(β-d-glucopyranosyloxy) coumarin	A. deliciosa [89]	Peels

Lignans

Lignans also had a narrow distribution in kiwi plants, only six members have been identified from Actinidia plants (269‒274, Fig. 12, Table 11). (+)-Pinoresinol 271, (+)-medioresinol 272, and (−)-syringaresinol 273 were partitioned from the fraction of the roots of A. arguta [53]. Compound 271 is a biologically active lignan and widely found in many dietary plants. It was reported to possess antifungal, anti-inflammatory, antioxidant, hypoglycemic, and antitumor activities [158–162]. A study on this compound suggested that 271 displayed significant inhibition of fMLP/CB-induced superoxide anion generation and elastase release, with an IC₅₀ value of 1.3 ± 0.2 μg/mL [159]. The 50% ethanol extract of A. arguta showed strong inhibitory effect on α-glucosidase (32.6%), while a bio-guided isolation on the extract gave a bioactive compound pinoresinol diglucoside 274 [138].

Fig. 12.

Structures of lignans 269‒274 from Actinidia plants

Table 11.

Information of of lignans from Actinidia plants

No.	Compound name	Species Refs.	Part		Cytotoxicity Refs.
269	Urolingoside	A. polygama [110]	Aerial parts
270	4′-O-β-Dxylopyranoside	A. chinensis Radix [50]		Roots
271	(+)-Pinoresinol	A. arguta [53]	Roots		Antifungal (in vitro) [158] Anti-inflammatory (in vitro) [159] Antioxidation (in vitro) [160] Hypoglycemic (in vitro) [161] Anti-tumor (in vitro) [162]
272	(+)-Medioresinol	A. arguta [53]	Roots
273	(−)-Syringaresinol	A. arguta [53]	Roots
274	Pinoresinol diglucoside	A. arguta [138]	Leaves		Inhibiting α-glucosidase (in vitro) [138]

Simple Phenols

Simple benzene derivatives including glycosides and isoprenylated benzene products from Actinidia plants were collected (275‒298, Fig. 13, Table 12). Phytochemical examination of the fruits of A. arguta led to the isolation of protocatechuic acid 279 [135]. It showed anti-inflammatory [163], antioxidant [163], neuroprotective [164], and anti-proliferative activities [165]. Protocatechuic acid exhibited significant (p < 0.05) anti-inflammatory (83% and 88% inhibition for egg-albumin induced and xylene induced oedema, respectively), analgesic (56% inhibition and 22 s of pain suppression for acetic acid-induced and hot plate-induced pain, respectively), and antioxidant effects (97% inhibition and absorbance of 2.516 at 100 μg/mL for DPPH and FRAP assay, respectively) in the models [166]. Extraction of leaf tissue from the golden-fleshed kiwifruit cultivar A. chinensis “Hort16A” expressing genotype-resistance against the fungus Botrytis cinerea, a new phenolic compound, 3,5-dihydroxy-2-(methoxycarbonylmethyl)phenyl 3,4-dihydroxybenzoate 278 was therefore obtained [167].

Fig. 13.

Structures of simple phenols 275‒298 from Actinidia plants

Table 12.

Information of simple phenols from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
275	Tyrosol	A. arguta [168]	Roots	Anti-​inflammatory (in vitro) [151]
276	2,2-Dimethyl-6-chromancarboxylic acid	A. deliciosa [150]	Roots
277	Monodictyphenone	A. chinensis Radix [50]	Roots	Inhibiting protein tyrosine phosphatase (in vitro) [169]
278	3,5-Dihydroxy-2-(methoxycarbonyl methyl) phenyl 3,4-dihydroxybenzoate	A. chinensis [167]	Leaves
279	Protocatechuic acid	A. arguta [135]	Fruits	Anti-inflammatory and antioxidant (in vitro and in vivo) [163] Neuroprotective (in vitro) [164] Anti-proliferative (in vitro) [165]
280	4-Hydroxy benzoic acid	A. arguta [92]	Roots
281	Vanillic acid	A. deliciosa [150]	Roots
282	4-(β-d-Glucopyranosyloxy)-3-hydroxybenzoic acid	A. chinensis Radix [50]	Roots
283	p-Hydroxybenzaldehyde	A. chinensis Radix [50]	Roots
284	Tachioside	A. deliciosa [150]	Roots
285	Syringaldehyde	A. chinensis Planch [105]	Roots	Anti-inflammatory (in vitro) [170]
286	Vanillic acid 4-O-β-d-glucopyranoside	A. deliciosa [150]	Roots
287	Protocatechualdehyde	A. chinensis [171]	Roots	Antioxidant and anti-inflammatory (in vitro) [172]
288	4-Hydroxy-2-methoxyphenyl-β-d-glucopyranoside	A. macrosperma [66]	Roots
289	Erythro-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol	A. chinensis [171]	Roots
290	Threo-1,2-bis-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol	A. chinensis [171]	Roots
291	Planchols A	A. chinensis Planch [94]	Roots	Against P-388 and A-549 cell lines (in vitro) [94]
292	Planchols B	A. chinensis Planch [94]	Roots	Against P-388 and A-549 cell lines (in vitro) [94]
293	Planchols C	A. chinensis Planch [94]	Roots	Against P-388 and A-549 cell lines (in vitro) [94]
294	Planchols D	A. chinensis Planch [94]	Roots	Against P-388 and A-549 cell lines (in vitro) [94]
295	2,8-Dimethyl-2-(4,8,12-trimethyltridec-11-enyl)chroman-6-ol	A. deliciosa [89]	Peels
296	α-Tocopherol	A. deliciosa [89]	Peels
297	δ-Tocopherol	A. deliciosa [89]	Peels
298	2,8-Dimethyl-2-(4,8,12-trimethyltridec-11-enyl)chroman-6-ol	A. chinensis [173]	Peels

Four novel skeleton phenolic compounds planchols A‒D (291‒294) were isolated from the roots of A. chinensis Planch. Their structures were elucidated by spectroscopic analysis and chemical evidence. The structure of 291 was further confirmed by the single-crystal X-ray diffraction. Moreover, it was found that 291 and 292 showed remarkable cytotoxic activity against P-388 with IC₅₀ of 2.50 and 3.85 μM, respectively, and against A-549 with IC₅₀ of 1.42 and 2.88 μM, respectively [94].

Miscellaneous

Three alkaloids (299‒301), eleven fatty acids and derivatives (302‒312), and other thirteen small molecules (313‒325) were obtained from Actinidia plants (Fig. 14, Table 13). Actinidine 299 and boschniakine 300 were isolated from the leaves and galls of A. polygama and also isolated from A. arguta which might be converted from iridoids [174, 175]. A bioassay-guided fractionation of the fruits of A. polygama led to the separation and identification of a polyunsaturated fatty acid, α-linolenic acid (ALA) 305 [176]. This compound was found to possess a broad biological properties including anti-inflammatory [177], anti-tumor [178], anti-hyperlipidemic [179], anti-diabetic [180], and anti-fungal [181] activities. By a bio-guided fractionation, a ceramide namely actinidiamide 312 was identified as an anti-inflammatory component from the EtOAc fraction of A. polygama Max. It potently inhibited nitric oxide production (30.6% inhibition at 1 μg/mL) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells and β-hexosaminidase release (91.8% inhibition at 1 μg/mL) in IgE-sentized RBL-2H3 cells [182].

Fig. 14.

Structures of other molecules 299‒325 from Actinidia plants

Table 13.

Information other molecules from Actinidia plants

No.	Compound name	Species Refs.	Part	Bioactivity Refs.
299	Actinidine	A. polygama [174]	Leaves and galls	Anti-obesity (in vivo) [183]
300	Boschniakine	A. arguta [175]
301	Indole-3-carboxylic acid	A. chinensis Planch [184]	Roots
302	Undecanoic acid	A. deliciosa [185]	Roots	Anti-inflammatory (in vivo) [186]
303	n-Stearic acid	A. deliciosa [150]	Roots
304	Tetracosanoic acid	A. eriantha Benth [41]	Roots
305	α-Linolenic acid	A. polygama [176]	Fruits	Anti-inflammatory (in vivo) [177] Anti-tumor (in vivo) [178] Anti-hyperlipidemic (in vivo) [179] Anti-diabetic (in vivo) [180] Anti-fungal (in vitro) [181]
306	(9Z,11E)-13-Hydroxy-9,11-octadecadienoic acid	A. chinensis Radix [50]	Roots
307	Ricinoleic acid	A. chinensis Radix [50]	Roots
308	Lignoceric acid	A. chinensis Planch [187]	Roots
309	Stearyl-β-d-glucopyranoside	A. chinensis Planch [187]	Roots
310	Dotriacontanic acid	A. chinensis Planch [52]	Roots
311	Sphingolipid	A. chinensis Planch [52]	Roots
312	Actinidiamide	A. polygama [182]	Fruits	Anti-inflammatory (in vitro) [182]
313	n-Butyl-O-β-d-fructopyranoside	A. deliciosa [188]	Roots
314	Sucrose	A. chinensis Planch [187]	Roots
315	γ-Quinide	A. chinensis Planch [187]	Roots
316	1-Methyl-5-ethyl citrate	A. arguta [136]	Fruits
317	1,6-Dimethyl citrate	A. arguta [136]	Fruits
318	1,5,6-Trimethyl citrate	A. arguta [136]	Fruits
319	1,6-Dimethyl-5-ethyl citrate	A. arguta [136]	Fruits
320	6-Butyl citrate	A. arguta [136]	Fruits
321	1-Methyl-6-butyl citrate	A. arguta [136]	Fruits
322	Succinic acid	A. kolomikta [189]	Leaves
323	Meso-inositol	A. kolomikta [189]	Leaves
324	Maltose	A. kolomikta [189]	Leaves
325	α-Kolomiktriose	A. kolomikta [190]	Roots

In summary, this review focused on the biological components and related pharmacological activities of various parts of Actinidia plants, including triterpenoids, steroids, flavonoids, catechins, coumarins, lignans, phenols, and other small organic molecules. A total of 325 molecules have been collected in this review. Most of the active molecules are derived from the roots of Actinidia plants, while triterpenes and flavonoids are the most important types regardless of the number of compounds and their biological activity significance. The stems, leaves, fruit galls, and other parts of kiwi are mainly rich in flavonoids, phenylpropionic acids, and other small molecule compounds. Currently, these chemical components are not structurally novel. In addition, there are few in-depth researches on pharmacological activities of the bioactive compounds. Therefore, research on the chemical constituents of Actinidia plants is still promising. We hope that this review can provide positive information for the further exploration of the chemical components and their biological activities of Actinidia plants.

Funding

This work was financially supported by the National Natural Science Foundation of China (22177139) and the Scientific Research Program of Hubei Provincial Department of Education, China (D20183001).