Skip to main content
NCBI home page
Molecules logoLink to Molecules
. 2022 Oct 27;27(21):7302. doi: 10.3390/molecules27217302

Volatile Profiling of Magnolia champaca Accessions by Gas Chromatography Mass Spectrometry Coupled with Chemometrics

Chiranjibi Sahoo 1, Bibhuti Bhusan Champati 1, Biswabhusan Dash 1, Sudipta Jena 1, Asit Ray 1, Pratap Chandra Panda 1, Sanghamitra Nayak 1,*, Ambika Sahoo 1,*
Editor: Lukasz Komsta1
PMCID: PMC9658739  PMID: 36364127

Abstract

Magnolia champaca (L.) Baill. ex Pierre of family Magnoliaceae, is a perennial tree with aromatic, ethnobotanical, and medicinal uses. The M. champaca leaf is reported to have a myriad of therapeutic activities, however, there are limited reports available on the chemical composition of the leaf essential oil of M. champaca. The present study explored the variation in the yield and chemical composition of leaf essential oil isolated from 52 accessions of M. champaca. Through hydrodistillation, essential oil yield was obtained, varied in the range of 0.06 ± 0.003% and 0.31 ± 0.015% (v/w) on a fresh weight basis. GC-MS analysis identified a total of 65 phytoconstituents accounting for 90.23 to 98.90% of the total oil. Sesquiterpene hydrocarbons (52.83 to 65.63%) constituted the major fraction followed by sesquiterpene alcohols (14.71 to 22.45%). The essential oils were found to be rich in β-elemene (6.64 to 38.80%), γ-muurolene (4.63 to 22.50%), and β-caryophyllene (1.10 to 20.74%). Chemometrics analyses such as PCA, PLS-DA, sPLS-DA, and cluster analyses such as hierarchical clustering, i.e., dendrogram and partitional clustering, i.e., K-means classified the essential oils of M. champaca populations into three different chemotypes: chemotype I (β-elemene), chemotype II (γ-muurolene) and chemotype III (β-caryophyllene). The chemical polymorphism analyzed in the studied populations would facilitate the selection of chemotypes with specific compounds. The chemotypes identified in the M. champaca populations could be developed as promising bio-resources for conservation and pharmaceutical application and further improvement of the taxa.

Keywords: Magnolia champaca, Michelia champaca, essential oil, chemometrics analysis

1. Introduction

Essential oils are volatile organic compounds with a strong aroma. These are produced by aromatic plants as secondary metabolites to protect against microbes, fungi, viruses, and insects. The essential oils attract pollinators to disperse pollens and seeds and also repel insignificant others [1]. Essential oils (EOs) possess various bioactivities, i.e., antimicrobial, anti-inflammatory, antioxidant, etc., which make them a valuable commercial product in the pharmaceutical, cosmetic, food, and beverages industries [2,3]. As evidenced by literature survey, there is growing research interest in essential oils of various aromatic plants and their bioactive components [4,5,6]. An essential oil’s biological activity might result from the presence of only one active ingredient or the synergistic interactions of numerous different molecules [5]. Numerous researches have demonstrated the connection between essential oil variations and their bioactivities [2,7]. The yield and quality of essential oils are greatly influenced by genetic makeup, agronomic practices, plant age, climate, soil type, and composition [8,9,10]. Edaphic and abiotic factors affect the biosynthetic pathways of the volatile compounds, thereby leading to the development of chemotypes in a single species [11]. Furthermore, understanding the diversity of EOs would also make it easier to market certain chemotypes for use in food or phytopharmaceutical utilizations as well as for breeding better genotypes [3,12]. Therefore, a qualitative and quantitative analysis of EOs collected from different geographical regions would necessitate developing a promising bioresource for industrial purposes.

Magnolia champaca (L.) Baill. ex Pierre (syn. Michelia champaca L.), commonly known as Champak/Swarna Champa/Golden Champa, is a tall and magnificent evergreen tree belonging to the family Magnoliaceae. It is well known for its soothing and beautiful aromatic flowers, which help in relaxation. Geographically, Magnolia champaca is distributed throughout tropical and sub-tropical regions of Asia covering India, Nepal, China, Indonesia, Myanmar, Vietnam, Sri Lanka, Malaysia, and Thailand [13]. In India, wild populations of Champak are mainly found in the sub-Himalayan zone, south India, western ghat, and Assam. Traditionally, several parts of the plant are utilized in the treatment of various diseases such as inflammation, eye disorders, leprosy, cephalalgia, cough, gout, fever, colic, and antidote for scorpion and snake venoms, etc. [14]. The plant is reported to have several substantial pharmacological activities such as anti-diuretic, memory-enhancing, anti-diabetic, anti-inflammatory, antioxidant, antitumor, anti-microbial, and wound-healing properties [13,14].

M. champaca leaves are simple, alternate, and spiral, with a lamina of about 10–25 cm, lanceolate to elliptic-lanceolate, acuminate apex, acute base, the margin is slightly undulate, glabrous, strongly and reticulately nerved [15]. The leaf extract of M. champaca possesses anti-fertility, antibacterial, anti-inflammatory, antioxidant, analgesic, cytotoxic, antiulcerogenic, pro-cognitive, and helmintholytic activities [14,16,17,18,19,20,21]. Additionally, the leaves in an acidic medium inhibit mild steel corrosion [22]. Further, Champak leaf juice mixed with coconut oil is used for hair cleaning and removing lice and dandruff [23]. In addition, the market value of the dry leaf powder is $50 (for 100 leaves) and the essential oil is $13 (for 100 mL) (Sajee Sales; Shiva exports, India).

In spite of having enormous potential, few reports are available on phytoconstituent analysis of the leaf essential oil of M. champaca [24,25]. The available reports show that the M. champaca leaf essential oil is rich in sesquiterpenoids such as β-elemene, β-caryophyllene, α-humulene, β-selinene, and α-selinene, etc. [25]. However, to date, there is no report available regarding the variations in yield and phytochemical content of M. champaca leaf essential oil, necessitating the comparative assessment of essential oil among different populations.

Thus, the present research was conducted to explore the intraspecific variations in the phytochemical composition of M. champaca leaf essential oil collected from different geographic regions of Odisha, India. In order to find out the relationship among the accessions of Magnolia champaca, different chemometric analyses such as agglomerative hierarchical clustering (HCA), principal component analysis (PCA), partial least squares projection of latent structures (PLS), and partial least squares regression discriminant analysis (PLS-DA) were performed based on the essential oil compositions of the accessions. The results thus obtained were used to determine the Magnolia champaca chemotypes.

2. Results and Discussion

2.1. Essential Oil Yield

The hydrodistilled leaf essential oils of Magnolia champaca accessions were pale yellow in color with a strong odor. The essential oils from 52 accessions of M. champaca leaves were extracted, and the mean essential oil yield was determined using one-way ANOVA, followed by Tukey’s HSD test with a 95% confidence interval. A noteworthy difference in EO yield (%) on a fresh weight basis ranging from 0.06% to 0.31% (v/w) was observed among the populations of M. champaca (Table 1). The EO yield of accession MCL27 (0.31% v/w), collected from the Khordha district, was found to be the highest, followed by accessions MCL9 (0.29% v/w) and MCL32 (0.26% v/w) of Ganjam and Khordha district respectively. Similarly, the lowest essential oil yield was found in the accessions MCL3 and MCL4 (0.06% v/w) which were collected from the Bhadrak district. The essential oil yield of M. champaca in the present study was higher than that of the previous report [24], which reported an EO yield of 0.04% in fresh leaves collected from Brazil in different seasons. Further, the resulting variations in the essential oil yield might be due to seasonal variation, geographical location, genetic and environmental factors, etc., as reported in other species [2,3,4]. Our finding showing intraspecific variation in essential oil yield in M. champaca is in agreement with reports available in other species such as Croton gratissimus [26], Hypericum gaitii [3], Hedychium coronarium [27] and Curcuma longa [10], etc.

Table 1.

Geographical characteristics and essential oil yield of collected M. champaca accessions.

Sl No. Accession No. Location District Latitude Longitude Altitude (m) Oil Yield (%) * Date of Collection Voucher Specimen No.
1 MCL1 Basudebpur Bhadrak 21.132299 86.734740 5 0.11 ± 0.01 no 27 February 2022 2350/CBT
2 MCL2 Charampa Bhadrak 21.087979 86.520914 16 0.07 ± 0.01 pq 27 February 2022 2351/CBT
3 MCL3 Gelpur Bhadrak 21.044568 86.480404 16 0.06 ± 0.01 q 28 February 2022 2352/CBT
4 MCL4 Khordanga Bhadrak 21.084711 86.532225 14 0.06 ± 0.01 q 28 February 2022 2353/CBT
5 MCL5 Chauliaganj Cuttack 20.456451 85.902186 25 0.20 ± 0.01 fghi 11 March 2022 2354/CBT
6 MCL6 Sankarpur Cuttack 20.548721 85.618641 42 0.19 ± 0.01 ghij 11 March 2022 2355/CBT
7 MCL7 Zobra Cuttack 20.478640 85.896844 26 0.22 ± 0.01 defg 11 March 2022 2356/CBT
8 MCL8 Barlapalli Ganjam 19.385068 85.060824 5 0.25 ± 0.01 cd 23 March 2022 2357/CBT
9 MCL9 Korapalli Ganjam 19.285533 84.884574 22 0.29 ± 0.01 ab 23 March 2022 2358/CBT
10 MCL10 Chatrapur Ganjam 19.361912 84.989735 23 0.23 ± 0.01 cdef 23 March 2022 2359/CBT
11 MCL11 Raghunathpur Jagatsinghpur 20.368431 86.158429 14 0.18 ± 0.01 hijk 8 April 2022 2360/CBT
12 MCL12 Patenigan Jagatsinghpur 20.264791 86.187224 13 0.17 ± 0.01 ijkl 8 April 2022 2361/CBT
13 MCL13 Benupur Jagatsinghpur 20.245119 86.152115 12 0.18 ± 0.01 hijk 8 April 2022 2362/CBT
14 MCL14 Ameswarpur Jajpur 20.841792 86.328084 14 0.11 ± 0.01 no 18 April 2022 2363/CBT
15 MCL15 Baidyarajpur Jajpur 20.834910 86.315929 16 0.12 ± 0.01 mno 18 April 2022 2364/CBT
16 MCL16 Kalyanpur Jajpur 20.840515 86.336724 17 0.12 ± 0.01 mno 18 April 2022 2365/CBT
17 MCL17 Gulnagar Kendrapara 20.519592 86.414565 5 0.14 ± 0.01 lmn 4 May 2022 2366/CBT
18 MCL18 Tarada Kendrapara 20.390703 86.298042 11 0.16 ± 0.01 jkl 4 May 2022 2367/CBT
19 MCL19 Garapur Kendrapara 20.516980 86.423092 6 0.17 ± 0.01 ijkl 4 May 2022 2368/CBT
20 MCL20 Raintira Keonjhar 21.624656 85.579860 486 0.23 ± 0.01 cdef 25 May 2022 2369/CBT
21 MCL21 Dhenkpur Keonjhar 21.636924 85.603657 476 0.19 ± 0.01 ghij 25 May 2022 2370/CBT
22 MCL22 Bidyarajsahi Keonjhar 21.635674 85.575923 496 0.20 ± 0.01 fghi 25 May 2022 2371/CBT
23 MCL23 Forest park Khordha 20.257316 85.826255 36 0.10 ± 0.01 op 3 June 2022 2372/CBT
24 MCL24 Khandagiri Khordha 20.264246 85.783965 63 0.18 ± 0.01 hijk 3 June 2022 2373/CBT
25 MCL25 Durgamadhab nagar Khordha 20.291257 85.775147 72 0.21 ± 0.01 efgh 3 June 2022 2374/CBT
26 MCL26 Jaydev vihar Khordha 20.302974 85.805600 62 0.09 ± 0.01 opq 11 June 2022 2375/CBT
27 MCL27 Old town Khordha 20.241975 85.839274 20 0.31 ± 0.02 a 11 June 2022 2376/CBT
28 MCL28 Palasuni Khordha 20.303605 85.865650 21 0.12 ± 0.01 mno 11 June 2022 2377/CBT
29 MCL29 Nayapalli Khordha 20.303781 85.805565 65 0.17 ± 0.01 ijkl 15 June 2022 2378/CBT
30 MCL30 Tomando Khordha 20.233206 85.745459 29 0.22 ± 0.01 defg 15 June 2022 2379/CBT
31 MCL31 Gothapatna Khordha 20.294390 85.743991 78 0.21 ± 0.01 efgh 15 June 2022 2380/CBT
32 MCL32 Sampur Khordha 20.284518 85.773200 72 0.26 ± 0.01 bc 24 June 2022 2381/CBT
33 MCL33 Kalinga nagar Khordha 20.284124 85.775564 75 0.24 ± 0.01 cde 24 June 2022 2382/CBT
34 MCL34 Itamati nagar Nayagarh 20.136615 85.156632 71 0.19 ± 0.01 ghij 13 July 2022 2383/CBT
35 MCL35 Khandapada Nayagarh 20.128100 85.104011 106 0.15 ± 0.01 klm 13 July 2022 2384/CBT
36 MCL36 Pratapprasad Nayagarh 20.136224 85.140644 76 0.20 ± 0.01 fghi 16 July 2022 2385/CBT
37 MCL37 Old town Nayagarh 20.117820 85.110669 89 0.16 ± 0.01 jkl 16 July 2022 2386/CBT
38 MCL38 Siriapur Puri 19.993425 85.820178 9 0.20 ± 0.01 fghi 21 July 2022 2387/CBT
39 MCL39 Pipili Puri 20.135786 85.841370 14 0.21 ± 0.01 efgh 21 July 2022 2388/CBT
40 MCL40 Samalapur Puri 20.127881 85.840332 13 0.19 ± 0.01 ghij 21 July 2022 2389/CBT
41 MCL41 Chandanpur Puri 19.886747 85.814705 17 0.12 ± 0.01 mno 22 July 2022 2390/CBT
42 MCL42 Lathikata Sundargarh 22.136464 84.878344 186 0.09 ± 0.01 opq 27 July 2022 2391/CBT
43 MCL43 Udit nagar Sundargarh 22.221226 84.841473 196 0.11 ± 0.01 no 27 July 2022 2392/CBT
44 MCL44 Tensa Sundargarh 21.515307 85.102925 257 0.09 ± 0.01 opq 27 July 2022 2393/CBT
45 MCL45 Badagaon Sundargarh 22.169503 84.301875 252 0.11 ± 0.01 no 28 July 2022 2394/CBT
46 MCL46 Fuljhar Sundargarh 21.707314 85.102838 219 0.23 ± 0.01 cdef 28 July 2022 2395/CBT
47 MCL47 Basanti Sundargarh 22.221585 84.841456 196 0.11 ± 0.01 no 28 July 2022 2396/CBT
48 MCL48 Ruguda Sundargarh 21.726694 84.982909 155 0.18 ± 0.01 hijk 3 August 2022 2397/CBT
49 MCL49 Sector 4 Sundargarh 22.245085 84.874139 211 0.23 ± 0.01 cdef 3 August 2022 2398/CBT
50 MCL50 Rajamunda Sundargarh 21.867753 84.928222 163 0.12 ± 0.01 mno 4 August 2022 2399/CBT
51 MCL51 Panposh Sundargarh 22.226728 84.804252 188 0.09 ± 0.01 opq 4 August 2022 2400/CBT
52 MCL52 Tensa Sundargarh 21.522735 85.101525 444 0.18 ± 0.01 hijk 4 August 2022 2401/CBT
Open in a new tab

The essential oil yield is given in % (v/w) based on the fresh weight of the plant material, i.e., in mL/100 g fresh weight. The mean having different letters in a column was significantly different according to Tukey’s HSD test at p < 0.05. * Each sample was analyzed in triplicate.

2.2. Essential Oil Composition

The GC-MS analysis of the leaf EO of different M. champaca populations collected from eleven districts of Odisha showed wide heterogeneity in chemical constituents. The study revealed a total of 65 compounds through GC-MS analysis, showcasing 90.23 to 98.90% of the total oil composition. The compounds detected through the Elite-5 MS column are listed based on their elution order (Table 2). In all accessions, sesquiterpenes (68.58 to 81.44%) were found to be the major chemical class followed by monoterpenes (0.8 to 25.04%). To be specific, EOs were dominated by mostly sesquiterpene hydrocarbons (52.83 to 65.63%) followed by sesquiterpene alcohol (14.71 to 22.45%) (Table 2, Figure 1). The present result is also consistent with the previous literature, where the leaf essential oil of M. champaca collected from Brazil was rich in sesquiterpene hydrocarbons followed by oxygenated sesquiterpenes [24]. In all the populations, the major constituents were β-elemene, γ-muurolene, β-caryophyllene, germacrene B, n-hexadecanol, α-humulene, viridiflorene, bicyclogermacrene, methyl linoleate, linalool, etc. (Table 3). β-elemene (0.23 to 38.76%) (Table 3) was found to be the major constituent of the accessions collected from Jagatsinghpur, Puri, Cuttack, Khordha, Nayagarh, and Ganjam districts (Table 2). γ-muurolene (0.31 to 22.48%) (Table 3) was found to be the predominant constituent of the accessions collected from the Sundargarh and Keonjhar districts (Table 2). Likewise, β-caryophyllene (0.03 to 20.70%) (Table 3) was the major constituent of the accessions of the Jajpur, Bhadrak, and Kendrapara districts (Table 2). The occurrence of three different types of major constituents in different accessions might be due to the difference in geographical location, genetic and environmental factors prevailing at different germplasm collection sites. The phytoconstituents identified herewith have already been reported in the leaf essential oil of different Magnolia species [24,25,28,29,30].

Table 2.

Relative contents of each constituent in Magnolia champaca leaf essential oil from Bhadrak (N = 4), Cuttack (N = 3), Ganjam (N = 3), Jajpur (N = 3), Jagatsinghpur (N = 3), Kendrapara (N = 3), Keonjhar (N = 3), Khordha (N = 11), Nayagarh (N = 4), Puri (N = 4), Sundargarh (N = 11).

Sl No. Compounds RI a RI b Peak Area (%) *
Bhadrak Cuttack Ganjam Jagatsinghpur Jajpur Kendrapara Keonjhar Khordha Nayagarh Puri Sundargarh
1 (3E)-Hexenol 848 853 0.10 ± 0.01 c 0.17 ± 0.05 a - - - 0.16 ± 0.07 ab - 0.14 ± 0.05 b 0.10 ± 0.01 c - 0.14 ± 0.06 b
2 α-Pinene 928 939 - - - - - 0.58 ± 0.06 a - 0.15 ± 0.03 c - - 0.35 ± 0.17 b
3 α-Fenchene 945 952 - - - - - 0.79 ± 0.06 a - - - - 0.22 ± 0.09 b
4 Sabinene 967 975 - 0.11 ± 0.06 c - - - 1.90 ± 0.09 a - 0.18 ± 0.03 c - - 0.32 ± 0.20 b
5 β-Pinene 973 979 - 0.17 ± 0.08 d - - - 1.49 ± 0.09 b - 0.29 ± 0.11 c - - 1.68 ± 0.43 a
6 Myrcene 982 990 - - - - - 0.60 ± 0.06 a - 0.17 ± 0.04 b - - 0.19 ± 0.03 b
7 Limonene 1028 1029 - 0.45 ± 0.28 c - - 1.25 ± 0.03 b 7.36 ± 1.00 a - 0.11 ± 0.05 d - 1.14 ± 0.06 b 1.11 ± 0.85 b
8 (E)-β-Ocimene 1040 1050 - - - - - 3.82 ± 0.09 a - 0.27 ± 0.15 c - - 1.86 ± 0.72 b
9 Linalool 1096 1096 3.67 ± 0.18 c 3.53 ± 0.18 c 0.80 ± 0.07 g 1.87 ± 0.09 f 2.33 ± 0.12 ef 7.59 ± 0.38 a 2.40 ± 0.12 e 2.26 ± 0.11 ef 1.88 ± 0.09 ef 5.24 ± 0.26 b 2.95 ± 0.15 d
10 γ-Terpineol 1176 1199 - 0.17 ± 0.03 d - - 0.23 ± 0.01 c 0.61 ± 0.06 a - 0.17 ± 0.08 d - 0.35 ± 0.02 b 0.19 ± 0.09 d
11 Linalool formate 1191 1216 - 0.21 ± 0.08 a - - - 0.20 ± 0.03 a - 0.13 ± 0.05 c - 0.16 ± 0.01 b 0.16 ± 0.03 b
12 Menthyl acetate 1291 1295 1.46 ± 0.04 a 0.13 ± 0.01 c - - - - 0.13 ± 0.01 c 0.30 ± 0.16 b 0.16 ± 0.03 c 0.25 ± 0.02 b 0.24 ± 0.05 b
13 iso-Menthyl acetate 1306 1305 1.56 ± 0.02 a 0.14 ± 0.01 de - - - 0.11 ± 0.07 e 0.15 ± 0.02 de 0.31 ± 0.18 b 0.20 ± 0.04 cd 0.26 ± 0.02 bc 0.30 ± 0.07 b
14 δ-Elemene 1328 1338 1.99 ± 0.01 bcd 2.22 ± 0.56 b - 1.75 ± 0.04 d 1.95 ± 0.05 cd 0.24 ± 0.08 f 2.63 ± 0.58 a 1.89 ± 0.52 cd 1.74 ± 0.64 d 2.02 ± 0.08 bc 1.36 ± 0.92 e
15 α-Copaene 1367 1376 0.12 ± 0.05 d 0.28 ± 0.25 c 1.49 ± 0.07 b 0.23 ± 0.05 cd 1.62 ± 0.05 b 2.11 ± 0.09 a 0.28 ± 0.05 c 0.28 ± 0.12 c 0.22 ± 0.09 cd 0.34 ± 0.02 c 1.59 ± 0.33 b
16 β-Elemene 1383 1390 3.69 ± 0.18 f 15.93 ± 0.80 d 35.76 ± 1.79 a 18.51 ± 0.93 c 5.72 ± 0.29 ef 6.67 ± 0.33 e 3.42 ± 0.17 f 18.30 ± 0.92 cd 22.61 ± 1.13 b 19.11 ± 0.96 c 3.67 ± 0.18 c
17 (Z)-Caryophyllene 1399 1408 - 1.79 ± 0.94 a 0.12 ± 0.04 d 0.23 ± 0.02 c - - 0.12 ± 0.01 d 0.22 ± 0.21 c 0.27 ± 0.18 c - 0.38 ± 0.21 b
18 β-Caryophyllene 1412 1419 18.20 ± 0.91 a 1.00 ± 0.05 f 1.64 ± 0.08 ef 5.46 ± 0.27 c 18.79 ± 0.94 a 18.73 ± 0.94 a 8.57 ± 0.43 b 3.55 ± 0.18 d 2.93 ± 0.15 de 5.49 ± 0.27 c 4.00 ± 0.20 cd
19 γ-Elemene 1421 1436 1.76 ± 0.02 b 1.87 ± 0.65 ab 0.30 ± 0.05 d 1.17 ± 0.32 c 1.05 ± 0.05 c 0.14 ± 0.07 d 1.70 ± 0.09 b 1.19 ± 0.33 c 1.02 ± 0.20 c 1.16 ± 0.06 c 1.97 ± 0.68 a
20 Aromadendrene 1427 1441 0.13 ± 0.04 d 0.18 ± 0.08 b 0.07 ± 0.01 e 0.12 ± 0.01 d - 0.12 ± 0.07 d - 0.15 ± 0.06 c - - 0.21 ± 0.12 a
21 6,9-Guaiadiene 1434 1444 0.13 ± 0.04 f 0.27 ± 0.01 e - 0.35 ± 0.06 de 1.38 ± 0.03 b - 1.65 ± 0.07 a 0.34 ± 0.11 de 0.33 ± 0.11 de 0.48 ± 0.04 c 0.40 ± 0.13 cd
22 cis-Muurola-3,5-diene 1439 1450 0.14 ± 0.04 c 0.22 ± 0.02 b 0.12 ± 0.04 c 0.28 ± 0.03 b 0.23 ± 0.01 b - 1.36 ± 0.05 a 0.25 ± 0.07 b 0.21 ± 0.05 b 0.23 ± 0.01 b 0.26 ± 0.11 b
23 α-Humulene 1446 1454 6.42 ± 0.32 b 4.24 ± 0.21 de - 6.07 ± 0.30 bc 7.36 ± 0.37 a 5.40 ± 0.27 c 3.86 ± 0.19 e 4.68 ± 0.23 d 4.06 ± 0.20 de 2.92 ± 0.15 f 4.27 ± 0.21 de
24 allo-Aromadendrene 1452 1460 1.14 ± 0.04 a 0.17 ± 0.05 de - 0.19 ± 0.06 cd 0.20 ± 0.01 cd 0.13 ± 0.07 e 0.20 ± 0.02 cd 0.22 ± 0.07 bcd 0.22 ± 0.05 bcd 0.24 ± 0.01 bc 0.26 ± 0.15 b
25 cis-Cadina-1(6),4-diene 1464 1463 1.52 ± 0.02 a - 0.36 ± 0.05 b - - 0.18 ± 0.03 c - 0.21 ± 0.08 c - - 0.23 ± 0.02 c
26 γ-Gurjunene 1466 1477 - 1.82 ± 0.04 a 0.15 ± 0.04 de 1.69 ± 0.09 a 1.70 ± 0.05 a 0.20 ± 0.03 d - 0.38 ± 0.13 c 1.51 ± 0.26 b 0.27 ± 0.02 cd 0.25 ± 0.11 cd
27 γ-Muurolene 1481 1479 7.04 ± 0.35 b 3.48 ± 0.17 e 8.29 ± 0.41 b 5.37 ± 0.27 cd 4.29 ± 0.21 de 5.66 ± 0.28 c 16.62 ± 0.83 a 4.85 ± 0.24 cd 4.79 ± 0.24 cd 3.34 ± 0.17 e 17.50 ± 0.87 a
28 β-Selinene 1479 1490 1.67 ± 0.02 a 1.68 ± 0.25 a 1.08 ± 0.09 b 1.74 ± 0.04 a - 0.33 ± 0.08 c - 1.58 ± 0.19 a - - 1.58 ± 0.13 a
29 cis-β-Guaiene 1484 1493 0.19 ± 0.06 d 1.50 ± 0.09 b - 0.24 ± 0.06 d 1.15 ± 0.08 c 0.22 ± 0.03 d 1.48 ± 0.07 b 0.26 ± 0.17 d 1.76 ± 0.16 a 1.48 ± 0.04 b 1.56 ± 0.37 b
30 Viridiflorene 1487 1496 2.59 ± 0.13 e 7.95 ± 0.40 b 1.56 ± 0.08 f 6.37 ± 0.32 c 4.53 ± 0.23 d 8.81 ± 0.44 a - 3.82 ± 0.19 d 1.09 ± 0.05 f 8.37 ± 0.42 ab 7.00 ± 0.35 c
31 γ-Amorphene 1494 1495 0.31 ± 0.06 cd 0.46 ± 0.05 c 0.17 ± 0.04 d 1.62 ± 0.08 a - 1.27 ± 0.09 b - 1.61 ± 0.35 a 1.61 ± 0.08 a - 1.52 ± 0.56 a
32 Bicyclogermacrene 1498 1500 2.93 ± 0.15 ef 2.66 ± 0.1 f 6.30 ± 0.32 b 3.33 ± 0.17 de 2.37 ± 0.1 f - 7.36 ± 0.37 a 3.43 ± 0.17 de 5.93 ± 0.30 b 3.59 ± 0.18 d 4.49 ± 0.22 c
33 γ-Cadinene 1504 1513 0.15 ± 0.04 e 0.23 ± 0.09 e 0.21 ± 0.05 e 1.29 ± 0.09 d - - 4.11 ± 0.09 a 1.63 ± 1.24 c 4.15 ± 1.69 a 2.60 ± 0.08 b 0.19 ± 0.06 e
34 δ-Cadinene 1509 1523 1.83 ± 0.02 b 1.12 ± 0.65 d 1.47 ± 0.09 c 1.24 ± 0.04 d 0.27 ± 0.03 f 2.46 ± 1.53 a - 1.98 ± 0.35 b 0.22 ± 0.16 f 0.16 ± 0.01 fg 0.61 ± 0.42 e
35 (E)-iso-γ-Bisabolene 1513 1529 0.15 ± 0.04 f 0.12 ± 0.09 f 0.13 ± 0.04 f 0.17 ± 0.07 f 1.69 ± 0.08 b 0.17 ± 0.07 f 1.01 ± 0.07 e 1.43 ± 0.37 c 1.90 ± 0.31 a 1.26 ± 0.06 d 1.12 ± 0.82 de
36 trans-Cadina-1,4-diene 1521 1534 - 0.16 ± 0.06 a - 0.17 ± 0.08 a - - 0.13 ± 0.01 b 0.12 ± 0.04 b 0.08 ± 0.02 c - 0.13 ± 0.03 b
37 α-Cadinene 1525 1538 0.28 ± 0.06 a 0.17 ± 0.08 b 0.17 ± 0.05 b 0.16 ± 0.05 b - - 0.12 ± 0.01 c 0.12 ± 0.05 c 0.11 ± 0.03 c - 0.12 ± 0.02 c
38 Hedycaryol 1540 1548 1.51 ± 0.02 a 0.23 ± 0.13 de - 0.35 ± 0.02 c 1.51 ± 0.03 a 0.62 ± 0.06 b - 0.24 ± 0.10 de 0.16 ± 0.08 e - 0.32 ± 0.20 cd
39 Germacrene B 1555 1561 5.54 ± 0.28 d 6.69 ± 0.33 bc - 7.73 ± 0.39 a - 6.13 ± 0.31 cd 7.01 ± 0.35 ab 6.71 ± 0.34 bc 5.35 ± 0.27 d 5.45 ± 0.27 d
40 cis-Sesquisabinene hydrate (IPP vs. OH) 1552 1544 1.49 ± 0.02 b 3.16 ± 1.05 a - 1.51 ± 0.15 b - 0.37 ± 0.08 c - 1.67 ± 2.23 b - - 0.54 ± 0.05 c
41 cis-Muurol-5-en-4-α-ol 1558 1561 0.20 ± 0.06 c 0.23 ± 0.17 c - 0.15 ± 0.04 c 0.21 ± 0.01 c 0.13 ± 0.07 c - 0.15 ± 0.04 c 3.01 ± 4.01 a - 0.71 ± 0.69 b
42 trans-Dauca-4(11),7-diene 1562 1557 - - - - - - - 0.19 ± 0.05 b 0.12 ± 0.01 c 0.33 ± 0.02 a -
43 β-Copaen-4-α-ol 1566 1590 1.34 ± 0.03 c 0.39 ± 0.08 e 0.08 ± 0.01 g 0.28 ± 0.06 ef 1.48 ± 0.03 b 0.65 ± 0.06 d 0.20 ± 0.02 fg 0.35 ± 0.18 e 0.36 ± 0.13 e 1.85 ± 0.06 a 0.62 ± 0.61 d
44 α-Cedrene epoxide 1574 1575 - 0.41 ± 0.03 d 0.15 ± 0.04 ef - 1.40 ± 0.03 c - 0.27 ± 0.05 de 1.67 ± 0.35 b 1.54 ± 0.04 bc - 2.61 ± 1.26 a
45 Spathulenol 1571 1578 3.93 ± 0.68 a 1.90 ± 0.96 b 0.09 ± 0.01 f 1.49 ± 0.05 cd 1.55 ± 0.05 c 4.10 ± 1.15 a 1.28 ± 0.05 cde 1.05 ± 0.70 e 0.38 ± 0.18 f 1.95 ± 0.06 b 1.18 ± 0.98 de
46 Globulol 1585 1590 0.24 ± 0.06 f 1.70 ± 0.16 a - 1.42 ± 0.06 c 1.61 ± 0.08 ab 0.26 ± 0.08 f 1.53 ± 0.07 bc 0.32 ± 0.19 f 0.39 ± 0.18 f 1.23 ± 0.06 d 0.63 ± 0.68 e
47 Guaiol 1595 1600 0.12 ± 0.04 e 0.33 ± 0.13 c 0.09 ± 0.01 e 0.26 ± 0.04 cd 0.25 ± 0.01 d 0.64 ± 0.06 b 0.12 ± 0.01 e 0.15 ± 0.05 e 0.16 ± 0.11 e 1.54 ± 0.04 a 0.31 ± 0.24 cd
48 9,11-epoxy-Guaia-3,10(14)-diene 1599 1601 1.90 ± 0.02 a - - 0.16 ± 0.05 d - - - 0.28 ± 0.21 c 0.18 ± 0.04 d - 0.37 ± 0.19 b
49 10-epi-γ-Eudesmol 1610 1623 1.55 ± 0.03 b 1.90 ± 0.23 a 0.22 ± 0.05 e 1.23 ± 0.05 c 1.83 ± 0.05 a 0.18 ± 0.03 e 1.08 ± 0.09 cd 1.20 ± 0.55 c 1.83 ± 0.34 a 1.76 ± 0.04 a 0.89 ± 0.50 d
50 Muurola-4,10(14)-dien-1-β-ol 1618 1631 1.08 ± 0.03 c 1.83 ± 0.22 b 0.30 ± 0.05 e 1.12 ± 0.02 c 1.05 ± 0.05 c 4.71 ± 0.58 a 1.63 ± 0.07 b 1.02 ± 0.70 cd 1.57 ± 0.03 b 1.01 ± 0.06 cd 0.75 ± 0.36 d
51 γ-Eudesmol 1633 1632 1.79 ± 0.03 b 1.35 ± 0.58 e 1.55 ± 0.07 cde 1.11 ± 0.01 f 1.77 ± 0.08 bc 0.84 ± 0.06 g 1.48 ± 0.07 de 1.03 ± 0.36 fg 1.68 ± 0.28 bcd 1.82 ± 0.08 ab 2.01 ± 1.68 a
52 cis-Cadin-4-en-7-ol 1636 1636 0.18 ± 0.06 f 0.37 ± 0.12 e 1.75 ± 0.07 ab 1.43 ± 0.07 c 1.58 ± 0.05 bc 0.32 ± 0.08 ef 1.76 ± 0.07 a 1.43 ± 0.24 c 0.40 ± 0.21 e 1.57 ± 0.04 c 0.70 ± 0.45 d
53 epi-α-Cadinol 1640 1640 1.09 ± 0.03 c 1.58 ± 0.46 b - - 1.50 ± 0.03 b - 0.18 ± 0.02 f 0.32 ± 0.09 e 0.18 ± 0.07 f 0.49 ± 0.04 d 1.78 ± 4.05 a
54 α-Muurolol (=Torreyol) 1645 1646 1.14 ± 0.03 c 2.85 ± 0.71 a 1.83 ± 0.09 b 2.85 ± 0.58 a - 1.09 ± 0.06 c 1.72 ± 0.09 b 1.80 ± 0.59 b 1.72 ± 1.81 b 1.97 ± 0.08 b 1.96 ± 0.80 b
55 α-Cadinol 1652 1654 - - 1.64 ± 0.07 cd - 2.31 ± 0.08 b - 1.31 ± 0.09 e 1.86 ± 1.05 c 2.83 ± 0.46 a 1.39 ± 0.08 e 1.52 ± 1.49 de
56 Selin-11-en-4-α-ol 1653 1659 1.84 ± 0.02 bc 1.58 ± 0.41 cde 1.53 ± 0.07 de 1.58 ± 0.03 cde 4.25 ± 1.06 a 1.61 ± 0.09 bcd 1.30 ± 0.05 ef 1.88 ± 0.98 b 1.32 ± 1.78 ef 1.65 ± 0.04 bcd 1.06 ± 0.86 f
57 (Z)-Nerolidyl acetate 1668 1677 - - 0.11 ± 0.01 c - - 0.19 ± 0.03 b - 0.09 ± 0.01 c 0.09 ± 0.01 c - 0.66 ± 1.04 a
58 Eudesm-7(11)-en-4-ol 1699 1700 0.15 ± 0.04 c 0.17 ± 0.08 c 1.70 ± 0.07 a 0.18 ± 0.07 c 0.18 ± 0.01 c 0.41 ± 0.08 b - 0.18 ± 0.06 c 0.18 ± 0.09 c 0.14 ± 0.01 c 0.35 ± 0.18 b
59 (E)-Nerolidyl acetate 1709 1717 1.55 ± 0.02 c 0.21 ± 0.09 e 3.36 ± 0.09 a 0.13 ± 0.03 e 1.45 ± 0.08 cd 0.26 ± 0.08 e 1.24 ± 0.05 d 1.38 ± 0.22 cd 1.40 ± 0.24 cd 1.80 ± 0.06 b 1.29 ± 1.35 d
60 (Z)-Nuciferol 1727 1725 - - 1.45 ± 0.05 a - 0.26 ± 0.03 bc - - 0.13 ± 0.06 d - 0.23 ± 0.01 c 0.34 ± 0.23 b
61 γ-Costol 1744 1746 0.28 ± 0.06 d 0.24 ± 0.08 de 0.48 ± 0.05 c 0.23 ± 0.05 de 1.45 ± 0.03 a - 1.21 ± 0.05 b 0.18 ± 0.07 e 0.31 ± 0.03 d 0.31 ± 0.02 d 0.26 ± 0.09 de
62 n-Hexadecanol 1855 1875 2.51 ± 0.13 e 6.12 ± 0.31 b 6.02 ± 0.30 b 5.56 ± 0.28 bc 2.56 ± 0.13 e - 7.25 ± 0.36 a 5.15 ± 0.26 c 6.87 ± 0.34 a 5.50 ± 0.28 bc 4.18 ± 0.21 d
63 Manool oxide 1970 1987 - - 0.09 ± 0.01 d - - - - 0.12 ± 0.01 c 0.34 ± 0.04 a - 0.19 ± 0.03 b
64 Methyl linoleate 2055 2085 1.38 ± 0.07 f 3.16 ± 0.16 e 8.08 ± 0.40 a 1.89 ± 0.09 f 3.63 ± 0.18 cde - 4.62 ± 0.23 b 3.99 ± 0.20 c 4.15 ± 0.21 bc 3.76 ± 0.19 cd 3.27 ± 0.16 de
65 Linoleic acid 2111 2133 0.27 ± 0.06 ef 0.40 ± 0.25 de 1.88 ± 0.09 a 0.13 ± 0.04 fg 1.54 ± 0.05 b - 0.36 ± 0.05 c 1.44 ± 0.24 bc 0.49 ± 0.12 d 1.77 ± 0.04 a 0.55 ± 0.45 d
Monoterpenoids Hydrocarbon 3.02 ± 0.07 1.20 ± 0.02 - - 1.25 ± 0.03 16.84 ± 0.29 0.28 ± 0.05 1.90 ± 0.03 0.36 ± 0.13 1.81 ± 0.21 6.43 ± 0.03
Monoterpenoids Alcohol 3.67 ± 0.04 3.70 ± 0.31 0.80 ± 0.07 1.87 ± 0.64 2.56 ± 0.07 8.20 ± 0.08 2.40 ± 0.23 2.42 ± 0.05 1.88 ± 0.87 5.59 ± 0.32 3.14 ± 0.08
Sesquiterpenoid Hydrocarbon 59.81 ± 0.38 56.24 ± 0.74 59.37 ± 0.03 65.63 ± 0.35 54.29 ± 0.17 52.83 ± 0.47 60.73 ± 0.43 59.80 ± 0.14 63.64 ± 0.80 58.41 ± 0.64 60.49 ± 0.26
Sesquiterpenoid Alcohol 17.97 ± 0.25 19.80 ± 0.15 14.71 ± 0.21 14.97 ± 0.53 22.45 ± 0.25 15.75 ± 0.24 16.05 ± 0.08 16.07 ± 0.08 17.79 ± 0.34 20.49 ± 0.39 17.24 ± 0.29
Other 5.77 ± 0.33 10.48 ± 0.25 17.68 ± 0.28 7.92 ± 0.09 10.91 ± 0.09 0.78 ± 0.09 13.50 ± 0.83 13.06 ± 0.23 13.76 ± 0.45 11.60 ± 0.03 11.60 ± 0.59
Total 90.23 ± 2.51 91.42 ± 2.57 92.56 ± 2.58 90.40 ± 1.52 91.46 ± 2.48 94.40 ± 3.60 92.96 ± 1.89 93.25 ± 0.76 97.44 ± 1.53 97.90 ± 1.04 98.90 ± 0.30
Open in a new tab

- Compounds not detected. RI a: Retention indices on Elite-5 column, experimentally determined using homologous series of C8-C20 n-alkanes. RI b: Retention index taken from literature [31]. Identification methods: MS, comparison of mass spectra with NIST library; RI, comparison of retention index with those reported in literature. The mean having different letters in a row is significantly different according to Tukey’s HSD test at p < 0.05. * Each sample was analyzed in triplicate.

Figure 1.

Figure 1

Open in a new tab

Relative percentages of chemical constituents’ classes in the essential oil of Magnolia champaca from different regions of Odisha, India.

Table 3.

Concentration (min and max) of top 10 constituents of Magnolia champaca leaf essential oil as identified by GC-MS.

Sl No. Compounds Concentration Range (%) Accession No. with Highest % Collection Site
1 β-Elemene 0.23–38.76 MCL9 Ganjam
2 γ-Muurolene 0.31–22.48 MCL48 Sundargarh
3 β-Caryophyllene 0.03–20.70 MCL16 Jajpur
4 Bicyclogermacrene 1.26–14.54 MCL42 Sundargarh
5 Methyl linoleate 1.14–10.60 MCL27 Khordha
6 Viridiflorene 0.16–11.02 MCL42 Sundargarh
7 n-Hexadecanol 1.43–9.47 MCL36 Nayagarh
8 Linalool 1.02–9.59 MCL17 Kendrapara
9 Germacrene B 0.06–9.78 MCL51 Sundargarh
10 α-Humulene 1.07–8.20 MCL1 Bhadrak
Open in a new tab

Although several phytoconstituents were restricted to one or a small number of populations, the majority were found in varying concentrations in different accessions (Table 2). For example, α-fenchene (0.22–0.79%) was observed only in populations of Kendrapara and Sundargarh districts. Similarly, α-pinene (0.15–0.58%), myrcene (0.17–0.6%), and (E)-β-ocimene (0.27–3.82%) were detected in populations collected from Khordha, Kendrapara and Sundargarh district, however, they were completely absent in the other groups. Our finding showing intraspecific variation in essential oil composition in M. champaca is in agreement with reports available in other species such as Croton gratissimus [26], Myristica fragrans [32], Hypericum gaitii [3], Hedychium coronarium [27] and Curcuma longa [10], etc. The variation in phytoconstituent levels might be due to the place of occurrence of the plant populations, soil characteristics, and predominant environmental factors, of which rainfall and temperature are important parameters [2,3]. As reported [33], the distribution of essential oil chemotypes is related to abiotic factors (temperature, moisture, topography, and edaphic factors) of the region which act on genes of the terpenoid biosynthetic pathways and contribute to the development of diverse essential oil profiles. The chemical diversity observed among M. champaca populations resulting from bioclimatic and geographical variables necessitates designing suitable conservation and sustainable utilization strategies, by considering these aspects. Furthermore, all populations representing different chemotypes need to be conserved utilizing different conservation approaches [3,34].

2.3. Multivariate Analysis of phytoconstituents

Chemometrics analyses such as PCA, PLS-DA, and sPLS-DA were performed to determine the chemotypes and cluster analyses such as hierarchical clustering, i.e., dendrogram and partitional clustering, i.e., K-means to understand the associations among studied populations of M. champaca concerning their EOs’ composition and contents.

A dendrogram was constructed based on the Ward linkage-clustering algorithm method using Euclidean distance measures between groups. Concerning the constructed dendrogram, the studied populations were separated into two major clusters, i.e., cluster I and cluster II (Figure 2). Cluster I included the populations collected from Jagatsinghpur, Cuttack, Puri, Khordha, Nayagarh, and Ganjam districts and is characterized by a high content of β-elemene (14.28–38.80%). Cluster II was further subdivided into two subclusters (cluster IIA and IIB) representing two distinct chemotypes. The subcluster IIA included the populations collected from Sundargarh and Keonjhar districts and is characterized by a high content of γ-muurolene (14.92–22.50%) whereas the subcluster IIB included the populations collected from Jajpur, Bhadrak and Kendrapara district and was rich in β-caryophyllene (14.22–20.74%). The variations in the composition of the essential oils in plant species and their principal compounds are possibly because of the changes in abiotic factors such as moisture, temperature and topography which regulate the terpene biosynthesis pathway. This alteration in the biosynthetic pathway can lead to the occurrence of new chemotypes in a plant species [2,35]. Also, the variations in the constituents of the EOs might be connected with microclimatic criteria such as temperature, precipitation or phenological state, which are found to be different in the collection site of M. champaca and are possible explanation to alter the oil phytochemical compositions [24,36,37]. Further K-means cluster analysis was prepared by taking the components of EO (variable indices) on the X-axis and their relative intensities on the Y-axis (Figure 3). Different colors represent different clusters and their concentrations. The lines are the median intensities of corresponding clusters. Cluster 1 (red), cluster 2 (green), and cluster 3 (blue) represent the accessions rich in β-elemene, γ-muurolene, and β-caryophyllene, respectively.

Figure 2.

Figure 2

Open in a new tab

Dendrogram illustrating cluster analysis (distance measure and clustering algorithm were. done using Euclidean and Ward). M. champaca accessions are indicated by names according to Table 1.

Figure 3.

Figure 3

Open in a new tab

K-means cluster analysis. The X-axis represents phytoconstituents and the Y-axis represents its relative intensities. The median intensities of corresponding clusters are shown in different colored lines.

In order to determine the linkages between the M. champaca populations, a PCA analysis was performed based on the composition of the essential oils. PCA divided the populations into three groups, confirming the dendrogram’s clustering structure. PCA revealed a total of five principal components (PC) explaining approximately 86.90% of the overall variance. In the score plot, the two principal components (PC1 and PC2) that account for the maximum variation of 69.30% (amongst the populations under study) are shown. (Figure 4). Similarly, score plots generated by PLS-DA, sPLS-DA and K-means clustering show similar distinctions within PCs. Cumulatively pairwise score plots generated through PCA, PLS-DA, and sPLS-DA show a similar trend in the distribution of populations according to their variance (Figure 5).

Figure 4.

Figure 4

Open in a new tab

Score plot generated between the selected PCs with their variances. (A) PCA; (B) PLS-DA; (C) sPLS-DA; (D) K-means clustering.

Figure 5.

Figure 5

Open in a new tab

Pairwise score plots between the 5 selected components with their variances shown in the corresponding diagonal cell. (A) PCA; (B) PLSDA; (C) sPLS-DA.

Figure 6 depicts the loading plot of PC1 and PC2 illustrating the contribution of significant EO elements (>1%) in the M. champaca populations. The first principal component (PC1) accounts for up to 48.20% variation and had a positive correlation with γ-muurolene and β-caryophyllene (>0.20) but had a negative correlation with β-elemene (>−0.80). Whereas the second principal component (PC2) could explain 21.10% of the total variation and showed a negative correlation with γ-muurolene (>−0.60) and a positive relationship with β-elemene (>0.10) and β-caryophyllene (>0.60). Further biplot (Figure 7) was generated from the loading plots (Figure 6) by following the centering and normalization scaling method. Here the biplot was generated between two principal components, i.e., PC1 and PC2 which once again proved the three chemotypes with major constituents β-elemene, γ-muurolene and β-caryophyllene.

Figure 6.

Figure 6

Open in a new tab

Loadings plot between the selected PCs (PC1 vs. PC2) showing the involvement of major essential oil components (>1%) in the grouping of M. champaca accessions. (A) PCA; (B) PLS-DA.

Figure 7.

Figure 7

Open in a new tab

PCA biplot between the selected PCs (PC1 vs. PC2) showing the involvement of major essential oil components (>1%) in the grouping of M. champaca accessions. M. champaca accessions are indicated by names according to Table 1.

The resulting VIP score plot (Figure 8) represented the strength of each peak distinguishing M. champaca samples from different geographical origins. Populations with Variable Importance for the Projection (VIP) > 1 have more influence on population discrimination. The colored boxes against the plot indicate relative concentrations of the corresponding metabolite in each region. The phytoconstituent β-elemene, leading with a VIP score of > 5, is found to be dominant in the accessions of Jagatsinghpur, Cuttack, Puri, Khordha, Nayagarh and Ganjam districts, followed by γ-muurolene, with a score of >3, is found to be highest in the accessions of Sundargarh and Keonjhar district. Furthermore, β-caryophyllene, with a score of >1, is found to be the leading compound of M. champaca populations collected from the Jajpur, Bhadrak and Kendrapara districts.

Figure 8.

Figure 8

Open in a new tab

PLS-DA-VIP score plot showing important features of the major constituents of M. champaca leaf essential oil. The colored boxes on the right indicate the relative concentrations of the corresponding metabolite in each group under study.

Due to the diverse geographic origin of M. champaca accessions, the variances in the phyto-constituents are quite normal. Geographical differences expose the species to a variety of exogenous factor-related stresses that result in the development of a variety of secondary metabolites for their defense [38]. There are reports on other species where the variations in phytoconstituents of different eco-regions were explored by showing the effect of different genetic, climatic and edaphic factors on the variation of essential oil yield and its quality [3,26,27,32]. For the first time, the chemical diversity of leaf essential oil of M. champaca has been studied in association with different chemometric approaches such as clustering analysis, PCA, PLS-DA, and sPLS-DA. The chemometric approach has also been effectively used to analyze the correlation and variation in essential oil composition of other species [3,26,27,32].

3. Materials and Methods

3.1. Plant Material

Plant leaves of M. champaca were collected from different regions of Odisha in the months of February–August 2022 (Figure 9). The botanical identification of the species was done with the help of the literature and authenticated by Prof. Pratap Chandra Panda, Taxonomist, Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India. The herbarium specimens were prepared and deposited at the Herbarium of the Centre for Biotechnology, as a voucher. The geocoordinates of the areas of occurrence of plant accessions were logged by the GPS and the details are provided in Table 1.

Figure 9.

Figure 9

Open in a new tab

Map showing different regions of sample collection from Odisha, India.

3.2. Extraction of Essential Oils

For the isolation of the essential oil, fresh mature leaves measuring 150 g from each accession were cleaned and finely chopped before being subjected to hydrodistillation utilizing a Clevenger-type apparatus for 5 h. EO isolation from each accession was done in three replications to confirm the yield reproducibility. The EO was collected and dried over anhydrous sodium sulfate (Na2SO4). The EO, was stored in a glass vial at 4 ℃ for further GC-MS analysis. The EO’s yield was calculated following the equation:

% Yield of oil (v/w) = [volume of oil (in mL)/weight of fresh sample (in g)] × 100

3.3. GC-MS Analysis of Isolated EOs

For the analysis of the EOs of M. champaca, a gas chromatograph (Clarus 580, PerkinElmer, Waltham, MA, USA) attached to an SQ8S mass spectrometric detector was utilized where 99.99% pure helium was taken as mobile phase (flow rate = 1 mL/min). The EO obtained above was analyzed by injecting 0.1 μL of neat EO into the GC-MS. Separation was carried out on an Elite-5 MS column (30 m in length × 0.25 mm I.D., film thickness 0.25 μm). The oven temperature in the GC-MS was programmed as follows: 60 °C for 0 min, heated at 3 ℃/min to 220 ℃ with 7 min hold, and the total run time was set for 60.33 min. The source and transfer interface temperatures were set at 150 °C and 250 °C respectively. Scanning was performed over a mass scan range of 50–600 m/z with electron ionization mode at an ionization voltage of 70 eV. Turbo mass TM software 6.1 was utilized to obtain the mass spectra and ion chromatogram.

Identification of each constituent was performed based on the RI (Retention Index) determined by co-injecting a homologous series of straight chain n-alkanes (C8–C20) run under similar experimental conditions and by comparing calculated RI values with the literature values [31]. The identification of constituents was further confirmed by matching their mass spectra with the inbuilt NIST MS library (NIST 08). Quantification of the essential oil constituents was performed based on relative area percentages.

3.4. Statistical Analysis

To compare the statistical differences in EO yield (%) and quality amongst M. champaca populations, one-way ANOVA followed by the Tukey HSD test at a 95% confidence level was performed using the statistical software Minitab 17. To investigate the similarity and relationship among M. champaca populations based on EO chemical constituents, chemometrics analyses such as Principal Component Analysis (PCA), Partial Least Squares—Discriminant Analysis (PLS-DA), and Sparse Partial Least Squares—Discriminant Analysis (sPLS-DA), and cluster analyses such as hierarchical clustering, i.e., dendrogram and partitional clustering, i.e., K-means clustering was used. The chemometric analysis such as PCA, PLS-DA, sPLS-DA, dendrogram, and K-means clustering was performed using the MetaboAnalyst 5.0, a comprehensive web-based metabolomics analysis tool (https://www.metaboanalyst.ca/ accessed on 21 September 2022). For the chemometrics analysis phytoconstituents with a peak area >1% in at least a single population were chosen as variables. Euclidean distance was used to measure the dissimilarity between populations, and Ward’s variance-minimizing method was performed for hierarchical clustering [39,40].

4. Conclusions

This is the first report on the chemical diversity analysis of the leaf essential oil of Magnolia champaca. This research revealed significant quantitative and qualitative variations in the chemical profile of the M. champaca leaf essential oils from eleven districts of Odisha. Chemometrics techniques could effectively classify the accessions into three different chemotypes rich with β-elemene, β-caryophyllene and γ-muurolene. The result demonstrated that the chemical composition and yield of the essential oil of M. champaca might be influenced by the geographical origin of populations and environmental factors. The chemical polymorphism analyzed in the studied populations would facilitate the selection of chemotypes with specific compounds. The chemotypes identified in the Magnolia champaca populations could be developed as promising bio-resources for conservation, pharmaceutical application, and further improvement of the taxa.

Acknowledgments

We are grateful to Manoj Ranjan Nayak and S.C. Si for their constant support and encouragement in and out of the centre.

Author Contributions

Conceptualization, S.N. and A.S.; methodology, C.S. and B.B.C.; software, C.S. and B.D.; validation, C.S., A.S. and A.R.; formal analysis, C.S. and S.J.; investigation, C.S., S.J. and B.B.C.; Resources, S.N., A.R. and A.S.; data curation, C.S. and B.B.C.; writing-original draft preparation, C.S.; writing-review and editing, A.S., S.N. and A.R.; supervision, A.S., P.C.P. and S.N.; project administration, P.C.P., A.S. and S.N. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

Sample Availability

Samples of the compounds are not available from the authors.

Funding Statement

This research received no external funding.

Footnotes

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

  • 1.Bakkali F., Averbeck S., Averbeck D., Idaomar M. Biological effects of essential oils—A review. Food Chem. Toxicol. 2008;46:446–475. doi: 10.1016/j.fct.2007.09.106. [DOI] [PubMed] [Google Scholar]
  • 2.Ray A., Jena S., Dash B., Kar B., Halder T., Chatterjee T., Ghosh B., Panda P.C., Nayak S., Mahapatra N. Chemical diversity, antioxidant and antimicrobial activities of the essential oils from Indian populations of Hedychium coronarium Koen. Ind. Crops Prod. 2018;112:353–362. doi: 10.1016/j.indcrop.2017.12.033. [DOI] [Google Scholar]
  • 3.Kamila P.K., Ray A., Jena S., Sahoo A., Kar S.K., Nayak S., Panda P.C. Intraspecific variability in yield and chemical composition of essential oil of the endemic species Hypericum gaitii from different natural habitats of Eastern India. Plant Biosyst. :2021. doi: 10.1080/11263504.2021.2020356. in press . [DOI] [Google Scholar]
  • 4.Behura S., Sahoo A., Singh S., Jena S., Kar B., Nayak S. Variation in essential oil yield and volatile constituents of Curcuma aromatica rhizome from different regions of eastern and southern India. J. Essent. Oil Bear. Plants. 2021;24:1248–1255. doi: 10.1080/0972060X.2021.2023367. [DOI] [Google Scholar]
  • 5.Sahoo A., Jena S., Ray A., Dash K.T., Nayak S., Panda P.C. Chemical constituent analysis and antioxidant activity of leaf essential oil of Curcuma xanthorrhiza. J. Essent. Oil Bear. Plants. 2021;24:736–744. doi: 10.1080/0972060X.2021.1955750. [DOI] [Google Scholar]
  • 6.Sahoo A., Dash B., Jena S., Ray A., Panda P.C., Nayak S. Phytochemical composition of flower essential oil of Plumeria alba grown in India. J. Essent. Oil Bear. Plants. 2021;24:671–676. doi: 10.1080/0972060X.2021.1965036. [DOI] [Google Scholar]
  • 7.Zhang D.Y., Yao X.H., Duan M.H., Wei F.Y., Wu G.H., Li L. Variation of essential oil content and antioxidant activity of Lonicera species in different sites of China. Ind. Crops Prod. 2015;77:772–779. doi: 10.1016/j.indcrop.2015.09.048. [DOI] [Google Scholar]
  • 8.Masotti V., Juteau F., Bessière J.M., Viano J. Seasonal and phenological variations of the essential oil from the narrow endemic species Artemisia molinieri and its biological activities. J. Agric. Food Chem. 2003;51:7115–7121. doi: 10.1021/jf034621y. [DOI] [PubMed] [Google Scholar]
  • 9.Angioni A., Barra A., Coroneo V., Dessi S., Cabras P. Chemical composition, seasonal variability, and antifungal activity of Lavandula stoechas L. ssp. Stoechas essential oils from stem/leaves and flowers. J. Agric. Food Chem. 2006;54:4364–4370. doi: 10.1021/jf0603329. [DOI] [PubMed] [Google Scholar]
  • 10.Sahoo A., Kar B., Jena S., Dash B., Ray A., Sahoo S., Nayak S. Qualitative and quantitative evaluation of rhizome essential oil of eight different cultivars of Curcuma longa L. (Turmeric) J. Essent. Oil Bear. Plants. 2019;22:239–247. doi: 10.1080/0972060X.2019.1599734. [DOI] [Google Scholar]
  • 11.Morshedloo M.R., Ebadi A., Maggi F., Fattahi R., Yazdani D., Jafari M. Chemical characterization of the essential oil compositions from Iranian populations of Hypericum perforatum L. Ind. Crops Prod. 2015;76:565–573. doi: 10.1016/j.indcrop.2015.07.033. [DOI] [Google Scholar]
  • 12.Aghbash B.N., Dehghan G., Movafeghi A., Talebpour A.H., Pouresmaeil M., Maggi F., Nojadeh M.S. Chemical compositions and biological activity of essential oils from four populations of Satureja macrantha C. A. Mey. J. Essent. Oil Bear. Plants. 2021;33:133–142. doi: 10.1080/10412905.2020.1871085. [DOI] [Google Scholar]
  • 13.Sinha R., Varma R. Michelia champaca L. (swarna champa): A review. Int. J. Enhanc. Res. Sci. Technol. Eng. 2016;5:78–83. [Google Scholar]
  • 14.Taprial S., Kashyap D., Mehta V., Kumar S., Kumar D. Antifertility effect of hydroalcoholic leaves extract of Michelia champaca L.: An ethnomedicine used by Bhatra women in Chhattisgarh state of India. J. Ethnopharmacol. 2013;147:671–675. doi: 10.1016/j.jep.2013.03.003. [DOI] [PubMed] [Google Scholar]
  • 15.Ramyashree C., Hemalatha K. Ethnomedicinal profile on magnolia species (Magnoliaceae): A review. Int. J. Herb. Med. 2020;8:39–46. [Google Scholar]
  • 16.Khan M.R., Kihara M., Omoloso A.D. Antimicrobial activity of Michelia champaca. Fitoterapia. 2002;73:744–748. doi: 10.1016/S0367-326X(02)00248-4. [DOI] [PubMed] [Google Scholar]
  • 17.Gupta S., Mehla K., Chauhan D., Nair A. Anti-inflammatory activity of leaves of Michelia champaca investigated on acute inflammation induced rats. Lat. Am. J. Pharm. 2011;30:819–822. [Google Scholar]
  • 18.Hossain M.M., Jahangir R., Hasan S.R., Akter R., Ahmed T., Islam M.I., Faruque A. Antioxidant, analgesic and cytotoxic activity of Michelia champaca Linn. Leaf. Stamford J. Pharm. Sci. 2009;2:1–7. doi: 10.3329/sjps.v2i2.5818. [DOI] [Google Scholar]
  • 19.Mullaicharam A.R., Kumar M.S. Effect of Michelia champaca Linn on pylorous ligated rats. J. Appl. Pharm. Sci. 2011;1:60–64. [Google Scholar]
  • 20.Ahmad H., Saxena V., Mishra A., Gupta R., Saraf S.A. Procognitive effects of hexane extracts of Michelia champaca leaves in normal and memory deficit mice. Pharmacogn. Commun. 2011;1:30–36. doi: 10.5530/pc.2011.2.6. [DOI] [Google Scholar]
  • 21.Dama G., Bidkar J., Deore S., Jori M., Joshi P. Helmintholytic activity of the methanolic and aqueous extracts of leaves of Michelia champaca. Res. J. Pharmacol. Pharmacodyn. 2011;3:25–26. [Google Scholar]
  • 22.Kumar S.A., Sankar A., Kumar S.R., Vijayan M. Magnolia champaca plant leaves extract for the inhibition of mild steel corrosion in acidic medium. Asian J. Res. Chem. 2013;6:1023–1026. [Google Scholar]
  • 23.Mandal U., Mallick S.K., Mahalik G. Ethnomedicinal plants used for the treatment and healing of skin diseases in Odisha, India: A review. Shodh Sanchar Bull. 2020;10:100–108. [Google Scholar]
  • 24.Lago J.H.G., Fávero O.A., Romoff P. Chemical composition and seasonal variation of the volatile oils from leaves of Michelia champaca L., Magnoliaceae. Rev. Bras. Farmacogn. 2009;19:880–882. doi: 10.1590/S0102-695X2009000600015. [DOI] [Google Scholar]
  • 25.Jiang D., Li Y., Xia B., He F., Pan H. Components and antibacterial functions of volatile organic compounds from leaves and flowers of Michelia champaka. J. Northeast For. Univ. 2012;40:71–74. [Google Scholar]
  • 26.Moremi M.P., Kamatou G.P., Viljoen A.M., Tankeu S.Y. Croton gratissimus-essential oil composition and chemometric analysis of an ethnomedicinally important tree from South Africa. S. Afr. J. Bot. 2021;138:141–147. doi: 10.1016/j.sajb.2020.12.015. [DOI] [Google Scholar]
  • 27.Ray A., Jena S., Haldar T., Sahoo A., Kar B., Patnaik J., Ghosh B., Panda P.C., Mahapatra N., Nayak S. Population genetic structure and diversity analysis in Hedychium coronarium populations using morphological, phytochemical and molecular markers. Ind. Crops Prod. 2019;132:118–133. doi: 10.1016/j.indcrop.2019.02.015. [DOI] [Google Scholar]
  • 28.Dai D.N., Thang T.D., Ogunwande I.A. Essential oil composition of four Magnoliaceae species cultivated in Vietnam. J. Herbs Spices Med. Plants. 2016;22:279–287. doi: 10.1080/10496475.2016.1194357. [DOI] [Google Scholar]
  • 29.Ha C.T.T., Thai T.H., Thanh T.X., Thuy D.T.T., Tra N.T., Ha N.T.T. Chemical composition and antimicrobial activity of the essential oils from stems and leaves of Michelia alba DC growing in Vietnam. Acad. J. Biol. 2018;40:96–105. [Google Scholar]
  • 30.Ha C.T.T., Thai T.H., Thuy D.T.T., Ky N.D., Tam H.M. Chemical composition and antimicrobial activity of the essential oil from twigs and leaves of Magnolia macclurei (Dandy) Figlar from Ha Giang Province, Vietnam. Acad. J. Biol. 2020;42:41–49. doi: 10.15625/2615-9023/v42n3.14739. [DOI] [Google Scholar]
  • 31.Adams R.P. Identification of Essential Oil Component by Gas Chromatography/Mass Spectrometry. 4th ed. Allured Publishing Corporation; Carol Stream, IL, USA: 2007. pp. 1–811. [Google Scholar]
  • 32.Dupuy N., Molinet J., Mehl F., Nanlohy F., Le Dréau Y., Kister J. Chemometric analysis of mid infrared and gas chromatography data of Indonesian nutmeg essential oils. Ind. Crops Prod. 2013;43:596–601. doi: 10.1016/j.indcrop.2012.07.073. [DOI] [Google Scholar]
  • 33.Croteau R., Gershenzon J. Genetic Control of Monoterpene Biosynthesis in Mints (Mentha: Lamiaceae) In: Ellis B.E., Kuroki G.W., Stafford H.A., editors. Genetic Engineering of Plant Secondary Metabolism. 1st ed. Volume 28. Springer; Boston, MA, USA: 1994. pp. 193–229. [Google Scholar]
  • 34.Al-Sagheer N.A. Magnolia champaca (L.) Baill. Ex Pierre (Magnoliaceae): A first report and a new record in the Arabian Peninsula (Yemen) J. Saudi Soc. Agric. Sci. 2021;20:243–247. doi: 10.1016/j.jssas.2021.02.003. [DOI] [Google Scholar]
  • 35.Zouari N., Ayadi I., Fakhfakh N., Rebai A., Zouari S. Variation of chemical composition of essential oils in wild populations of Thymus algeriensis Boiss. Et Reut., a North African endemic Species. Lipids Health Dis. 2012;11:28. doi: 10.1186/1476-511X-11-28. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Vallat A., Gu H., Dorn S. How rainfall, relative humidity and temperature influence volatile emissions from apple trees in situ. Phytochemistry. 2005;66:1540–1550. doi: 10.1016/j.phytochem.2005.04.038. [DOI] [PubMed] [Google Scholar]
  • 37.Lago J.H.G., Fávero O.A., Romoff P. Microclimatic factors and phenology influences in the chemical composition of the essential oils from Pittosporum undulatum Vent. Leaves. J. Braz. Chem. Soc. 2006;17:1334–1338. doi: 10.1590/S0103-50532006000700021. [DOI] [Google Scholar]
  • 38.Barra A. Factors affecting chemical variability of essential oils: A review of recent developments. Nat. Prod. Commun. 2009;4:1147–1154. doi: 10.1177/1934578X0900400827. [DOI] [PubMed] [Google Scholar]
  • 39.Ward J.H., Jr. Hierarchical grouping to optimize an objective function. J. Am. Stat. Assoc. 1963;58:236–244. doi: 10.1080/01621459.1963.10500845. [DOI] [Google Scholar]
  • 40.Ward J.H., Jr., Hook M.E. Application of an hierarchical grouping procedure to a problem of grouping profiles. Educ. Psychol. Meas. 1963;23:69–81. doi: 10.1177/001316446302300107. [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

The data presented in this study are available on request from the corresponding author.

Articles from Molecules are provided here courtesy of Multidisciplinary Digital Publishing Institute (MDPI)

RESOURCES