Polyphenolic profiles of a variety of wild berries from the Pacific Northwest region of North America

Abstract

Polyphenols have been extensively profiled and quantified in commercially grown berries, but similar information is sparsely available for wild berries. Because polyphenolic contents are inherently associated with berries health benefits, determining phenolic profiles is an important step for strategizing potential uses by the industry and for health and nutrition outcomes. Here, we profiled phenolic compounds in wild berries commonly encountered and harvested in the Pacific Northwest region of North America. Huckleberries (Vaccinium membranaceum) of varying phenotypes were found to be comparable to related blueberries in terms of general phenolic classes composition. However, all huckleberries exhibited markedly high levels of cyanidins, and delphinidins or peonidins were also higher in specific phenotypes. Wild black elderberries (Sambucus nigra spp. Canadensis) were found to have remarkably high phenolic, especially anthocyanins, in line with reports from cultivated elderberries. Saskatoon serviceberries (Amelanchier alnifolia) were found to exhibit high polyphenol content, but with a less diverse profile dominated by quercetin. The most intriguing berry may be the Oregon grape (Mahonia Aquifolium) being the only one exhibiting more than one g of polyphenols per 100 g; as well as a remarkably even distribution of the different anthocyanin classes. All colored wild berries were found to have at minimum comparable total phenolic contents when compared to cultivated and other wild berries, suggesting they should exhibit comparable human health benefits such as antioxidant and metabolic syndrome preventative potential described for these other berries. Overall, our data represents a valuable resource to explore the potential to valorize wild berry species for their specific phenolic profiles and predicted nutritional and health properties. With repeated phenolic profiling to better understand the impact of the environment, the wild berries described here hold promises both as food ingredient applications as well as valuable complement for healthy dietary patterns.

Graphical abstract

Highlights

• •Different wild berries were profiled for their anthocyanins, phenolic acids and flavonols.
• •Huckleberries compare to blueberries and higher in cyanidins.
• •Service berries high but low diversity polyphenols.
• •Oregon grapes high and diverse polyphenols.
• •Wild berries can be valorized for nutrition and health properties.

1. Introduction

Many small colored fruits, while not berries from a botanical perspective, make up a diversity of popular food sold and classified as berries. Berries are broadly accepted as beneficial for human nutrition and health (Drewnowski and Burton-Freeman, 2020; Kalt et al., 2020; Lavefve et al., 2020; Riordan and Solverson, 2022). While berries nutritional profiles are generally beneficial, most of their specific health potential has been attributed to their (poly)phenol contents (Fraga et al., 2019; Higbee et al., 2022; Solverson, 2020). Health benefits ranging from cardiometabolic improvements,brain health, antioxidant and inflammatory have been reported for the most popular and cultivated fruits such as blueberries (Kalt et al., 2020), blackberries (Solverson et al., 2018), raspberries (Dong et al., 2021; Huang et al., 2020) and strawberries (Huang et al., 2021). Health benefits evidence also exist for niche berries, but either with less reports available for example with black and red currants (Burgos-Edwards et al., 2020; McDougall et al., 2005; Shimada et al., 2022), or with more specific health benefits for example with cranberries (Al Othaim et al., 2021; Maki et al., 2016, 2018) and elderberries (Ferreira et al., 2022b).

Only very limited research efforts have been directed to studying health benefits associated with wild berries (or those with very limited commercial interest) dietary consumption (Higbee et al., 2022). It is generally assumed that similar health benefits can be expected because (1) (poly)phenols are generally abundant in berries, (2) the general nutrition profiles of berries fulfill the definition of healthy and nutrient-dense foods and (3) phylogenetic relationships often exist with the more studied berries. However, assumptions like these are not satisfactory because nutrient and phenolic analyses are lacking. Obviously, many wild berries are either considered not edible but possibly harboring folk medicine properties (Lans, 2016), or clearly toxic. On the other hand, wild berries may exhibit higher or different bioactive compounds, and maybe even both. Indeed, blue-colored berries such as blue honey suckle berries have been reported to harbor large amounts of anthocyanins (Grobelna et al., 2019, 2020; Senica et al., 2018) thereby leading to great potential as ingredient for functional foods (Grobelna et al., 2020).

For example, wild huckleberries (Vaccinium membranaceum and parvifolium), popular in the Northwestern region of the United States, have only been profiled for their phenolic content once (Lee et al., 2004). In this study, we aimed to determine the phenolic profiles of different wild berries with two major research questions. First, we report on the variation in phenolic profiles of phenotypically distinct accessions of mountain huckleberries (Vaccinium membranaceum). Second, we explore the phenolic profiles of other wild berries with limited to absent previous characterization, especially for non-cultivated plants in this geographic area. We then compare these profiles to conventionally grown blueberries, elderberries, and blackberries, as well as other wild berries. We particularly focus on the anthocyanin profiles of huckleberries and how they differ from their cultivated blueberries relatives. We also describe that other species harbor remarkably high levels of polyphenols that could be of interest for extraction and use as dietary supplements.

2. Materials and methods

2.1. Plant material

Ripe berries were identified and collected in the Inland Northwest Selkirk mountains of Washington and Idaho states of the United States of America. Different mountain huckleberries (Vaccinium membranaceum) accessions were distinguished based on common phenotypic traits, primarily berry color and leaves shape and assigned to five different phenotypes. DSCF 3984-4 stands out from the other accession by its bright red color, though this color is commonly considered a natural variation among the V. membranaceum (Fig. 1). 20200807-112352-6 is characterized by a red-purple hue, while the three other accessions harbor the more typical deep blue color and were distinguished based on the plants characteristics. Black elderberries (Sambucus nigra spp. Canadensis) and Saskatoon serviceberries (Amelanchier alnifolia) were harvested from a single tree each. Oregon grapes (Mahonia Aquifolium) and snow berries (Symphoricarpos albus) were collected from closely co-located bushes. Duke blueberries are maintained at the Washington State University Small Fruit Horticulture Research and Extension Program in Mount Vernon (WA, USA) and were collected when fully ripe.

Fig. 1.

PCA and visual phenotypic diversity in huckleberries and wild berries collected (N = 3 for each accession).

2.2. Reagents

HPLC reagents (formic acid and methanol) were from Fisher Scientific. (Fair Lawn, NJ, USA). Sodium carbonate, potassium persulphate, and Folin–Ciocalteau reagent were purchased from Merck (Darmstadt, Germany). Anthocyanin standards were purchased from Polyphenols Laboratories (Sandnes, Norway). Chlorogenic acid (3-caffeoylquinic acid), rutin, gallic acid, 6- hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), fluorescein sodium salt, 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH), 2,20- azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), (-)-epicatechin, and (þ)-catechin were from Sigma Aldrich (St. Louis, MO, USA). Isolated procyanidin standards were obtained from Mars Inc. (Hackettstown, NJ, USA).

2.3. Polyphenolic extracts

Polyphenols were extracted from berries following standard methods (Garzón et al., 2020; Wilkes et al., 2014). The polyphenolic extracts were obtained by homogenizing 5g fruit in 25 ml of extraction solution containing methanol/water/formic acid (60:37:3 v/v/v) to the smallest particle size using a Euro Turrax T18 Tissuemizer (Tekmar-Dohrman Corp, Mason, OH, USA) for 1 min. Homogenates were centrifuged for 5 min at 10,000 rpm. The pellet was re-extracted with 20 ml of extraction solution containing acetone/water/acetic acid (70:29.5:0.5 v/v/v) and centrifuged for 5 min at 10,000 rpm. Each of these extractions were repeated, and all the pooled supernatants and brought to a final volume of 100 ml in a volumetric flask. Prior to HPLC analysis, 5 ml of this extract was dried in a Thermo Savant Speed Vac Plus SC210A (Thermo Fisher Scientific, Waltham, MA), and residue reconstituted in 1 ml of 5% formic acid in water for anthocyanins and phenolic acids, or 1 ml of 50% methanol in water for flavonols. Samples were filtered through a 0.45 μm nylon syringe filter into a 1 ml HPLC vial prior to HPLC analysis.

2.4. HPLC analysis of polyphenolic extracts

The polyphenolic compounds were evaluated by HPLC. The anthocyanins and phenolic acids were identified and quantified using previously described methods (Cho et al., 2004). Samples (50 μL) were analyzed using a Waters HPLC system equipped with a model 600 pump, a model 717 Plus autosampler and a model 996 photodiode array detector. Separation was carried out using a 4.6 mm × 250 mm Symmetry C₁₈ column (Waters Corp, Milford, MA, USA) with a 3.9 mm × 20 mm Symmetry C₁₈ guard column. The mobile phase was a linear gradient of 5% formic acid (A) and methanol (B) from 2% B to 60% B for 60 min at 1 ml per min. The system was equilibrated for 20 min at the initial gradient prior to each injection. Detection wavelength was 510 nm for anthocyanins and 325 nm for phenolic acids. Individual anthocyanin monoglucosides and acylated anthocyanin derivatives were quantified as Delphinidins, Cyanidins, Petunidins, Peonidins and Malvidins glucoside equivalents, and phenolic acids were expressed as mg respective phenolic acid equivalents (chlorogenic acid for caffeoylquinic acid and ferulic, syringic, salicylic, vanillic, protocatechuic, coumaric, caffeic acid, and catechin for any of their respective derivatives) per100 g fresh berry weight. The flavonols were identified and quantified using another previously described method (Cho et al., 2005). Samples (50 μl) were analyzed using a Waters HPLC system (Waters Corp, Milford, MA, USA) equipped with a model 600 pump, model 717 plus autosampler and model 996 photodiode array detector. Separation was carried out using a 4.6 mm × 250 mm Aqua C₁₈ column (Phenomenex, Torrance, CA, USA) with a 3.0 mm × 4.0 mm ODS C₁₈ guard column (both columns from Phenomenex, Torrance, CA, USA). The mobile phase was a gradient of 2% acetic acid in water (A) and 0.5% acetic acid in water and acetonitrile (50:50 v/v, B) from 10% B to 55% B in 50 min and from 55% B to 100% B in 10 min. The system was equilibrated for 20 min at the initial gradient prior to each injection. A detection wavelength of 360 nm was used for flavonols at a flow rate of 1 ml per min. Flavonols were expressed as mg rutin equivalents per 100 g berry fresh weight.

2.5. p-Dimethylaminocinnamaldehyde (DMAC) assay

Total procyanidins present in the phenolic extract were measured using the p-Dimethylaminocinnamaldehyde (DMAC) assay (Payne et al., 2010) A solution of 3 mL of HCl in 27 mL alcohol was prepared and then 0.03 g of DMAC reagent was added to the solution (now be referred to as DMAC solution). Aliquots (50 μL) of blanks, standards, and extracts were prepared. 250 μL of DMAC solution was added to all prepared blanks, standards, extracts. Plate wells were read immediately at 640 nm. Catechin was used as the standard (2, 4, 8, 16, 32, and 64 mg/kg) with results expressed as mg of catechin equivalents per 100g fresh berry weight.

2.6. HPLC/ESI-MS analysis of polyphenolic extracts

An analytical Hewlett Packard 1100 series HPLC instrument (Palo Alto, CA, USA) equipped with an autosampler, binary HPLC pump and UV/VIS detector was used, as described previously (Garzón et al., 2020). Anthocyanins and flavonols were separated using the same HPLC conditions described above with detection at 520 nm for anthocyanins and 280 nm for flavonols. For HPLC/MS analysis the HPLC apparatus was interfaced to a Bruker (Billerica, MA, USA) model Esquire-LC/MS ion trap mass spectrometer. Mass spectral data were collected with the Bruker software, which also controlled the instrument and collected the signal at 280 nm. Typical conditions for mass spectral analysis in positive ion electrospray mode for anthocyanins and negative ion electrospray mode for flavonols included a capillary voltage of 4000 V, a nebulising pressure of 30.0 psi, a drying gas flow of 9.0 ml min−1 and a temperature of 300 °C. Data were collected in full scan mode over a mass range of m/z 50–1000 at 1.0 s per cycle. Characteristic ions were used for peak assignment. For compounds where chemical standards were commercially available, retention times were also used to confirm the identification of components.

2.7. Statistical analyses

The concentrations of phenolic compounds were determined on biological triplicates and are presented as average values ± standard error to the mean as calculated in Microsoft Excel. Multivariate analyses including Principal Component Analysis (PCA) were conducted in PAST 3.26 (Hammer et al., 2001).

3. Results and discussion

A Principal Component Analysis (PCA) based on the phenolic profiles of the berries was conducted (Fig. 1). The PCA confirmed that overall, huckleberries harbor similar phenolic compounds than the cultivated Duke blueberries. The service berries and elderberries were found to be more similar to blackberries and chokeberries as profiled by a similar approach previously (Stebbins et al., 2017; Wilkes et al., 2014). Finally, both the Oregon grapes and snow berries were markedly different from all berries. This appears logical for snow berries which are white and thereby expected to lack pigmented phenolic compounds, while this is an intriguing outcome for the M. aquifolium berries for which only partial antioxidant analyses had been performed previously (Andreicut et al., 2018).

3.1. Huckleberries phenolic profiles

Despite their differences in color, all huckleberries collected were similar in their overall phenolic profiles, with anthocyanins constituting the vast majority (approximately 200 mg per gram of fresh berry) of their phenolic contents (Fig. 2). In contrast with reported phenolic profiles of blueberries (Rodriguez-Mateos et al., 2012; Sellappan et al., 2002; Yousef et al., 2013), the huckleberries profiled here exhibit limited amounts of phenolic acids and flavonols. These lower levels in phenolic acids and flavonols are in line with reported levels in two different huckleberry species V. membranaceum and V. ovatum (Lee et al., 2004). The concentration of anthocyanins in wild huckleberries was similar to the levels reported in highbush and lowbush blueberries (Kalt et al., 2020; Rodriguez-Mateos et al., 2012; Stevenson and Scalzo, 2012), as well as the one we measured in Duke blueberries (220-250 mg/100g in huckleberries and 270 in Duke blueberries). Of note, one accession (DSCF3986-5) was markedly lower in anthocyanins. Anthocyanins, and most polyphenols generally, are also well known for their antioxidant properties and specifically polyphenols ability to directly scavenge free radical species (Cerqueira et al., 2023; Tsao, 2010).

Fig. 2.

Composition of main phenolic compound classes in the berries studies (N = 3 for each accession).

The DMAC assay showed that the blueberries contained 14.4 ± 0.39 mg catechin equivalents/100g All huckleberries had high levels of proanthocyanidins (PAC). (43.79 ± 3.31 to 93.31 ± 6.87 mg catechin equivalents/100g), at levels comparable to cranberries PAC (Howell et al., 2022). PAC levels were also comparable to those reported for tropical Vaccinium species from Costa-Rica (Esquivel-Alvarado et al., 2020) and Hawaii (Hummer et al., 2014). PAC extracts from cranberries and blueberries have been studied for their bacterial anti-adhesion properties (Howell et al., 2022; Liu et al., 2019) as well as for their potential to improve cardiometabolic biomarkers (Feldman et al., 2022; Morissette et al., 2020).The huckleberries tested here can thus be expected to harbor similar health effects.

3.2. Other wild berries phenolic profiles

As expected from the color, snow berries were devoid of anthocyanins (see Fig. 2, Fig. 3). However, they contain relatively high amounts of phenolic acids and very high amounts of flavonols. Specifically, very high amounts of quercetin rutinoside and kaempferol hexoside were detected (146.27 and 247.31 mg/100 g respectively). Quercetin has been extensively studied and identified as a flavonoid with many potential health properties (Papakyriakopoulou et al., 2022; Shabir et al., 2022; Yan et al., 2022), kaempferol as well but with less studies available (Imran et al., 2019; Jan et al., 2022). In addition, both are readily extracted for commercial applications, mostly as dietary supplements. While snow berries are notoriously inedible due to their saponin contents, they can grow in large quantities and represent an easy way to extract quercetin and kaempferol in large amounts. Of note, a process to remove saponins is commonly used for quinoa seeds (Craine et al., 2023; Jarvis et al., 2017), but would likely be more challenging to apply for high water content berries.

Fig. 3.

(A) Phenolic acids, (B) flavonols, and (C) anthocyanins levels (mg per 100 g of fresh berry) in the different berries (N = 3 for each accession).

Both the wild black elderberries and the service berries exhibited higher phenolic contents than huckleberries (see Fig. 2, Fig. 3). High total phenolic content have been previously reported from elderberries (Liu et al., 2022; Osman et al., 2023) and have been suggested to be the major reason for the berries purported health benefits (Ferreira et al., 2022a, 2022b; Liu et al., 2022). The vast majority of these phenolic acids were identified as (5- or 3-) caffeoylquinic acid, more commonly known as chlorogenic and neochlorogenic acids (CQA). CQAs have been reported from blueberries, cherries and many other plant sources (Mayta-Apaza et al., 2018, 2019; Rodriguez-Mateos et al., 2012), and are widely believed to promote weight loss and prevent diabetes despite somewhat conflicting evidence from the literature (Alcázar Magaña et al., 2021; Kumar et al., 2020; Singh et al., 2023; Tajik et al., 2017). Since only very high amounts of CQA can cause detrimental side effects, it can be concluded that the high phenolic acids are likely a beneficial property.

The DMAC assay performed on snow berries led to below detection signal (Birmingham et al., 2021), confirming the absence of procyanidins in this colorless berry, as expected. Elderberries contained relatively low PAC levels (14.4 ± 0.39 mg catechin equivalents/100g), while Oregon grapes (57.32 ± 3.86 mg catechin equivalents/100g) and service berries in particular (102.92 ± 20.21 mg catechin equivalents/100g) harbored PAC levels comparable to cranberries (Howell et al., 2022). High levels of procyanidins determined by UPLC have been reported in blue honeysuckle (Lonicera spp.) (Wojdyło et al., 2013). While a direct comparison of these quantification based on dry weight are difficult with our own measurements on fresh weight, we can conclude that several wild berries harbor high PAC concentrations rivalling the levels in foods generally seen as the best PAC dietary sources (Gu et al., 2004; Rue et al., 2018). PAC extracted from hawthorn berries have been studied for anticancer properties (Sun et al., 2022), though it should be noted that dense PAC polymers are unlikely to have bioactive properties.

3.3. Anthocyanins in huckleberries

Huckleberries exhibit low to absent levels of malvidins and petunidins relatively to blueberries (Table 1). Malvidin-3-glucoside (M-3-GLU) is well known as one of the most abundant anthocyanins in blueberries associated with specific health benefits such as endothelial function (Bharat et al., 2018), and intestinal homeostasis (Liu et al., 2023). There is less human health evidence available for petunidins (Li et al., 2021). This striking difference between huckleberries and blueberries anthocyanins profiles indicates that health benefits from huckleberries would be at least slightly different and warrants further investigation.

Table 1.

Anthocyanins levels in Huckleberries and Duke blueberries expressed in mg/100g of fresh berries (N = 3 for each accession). GAL: Galactoside; GLU: Glucoside; ARA: Arabinoside; HEX: Hexoside.

	Cyanidins			Delphinidins			Malvidins			Peonidins			Petunidins
	C-3-GAL	C-3-GLU	C-3-ARA	D-3-GAL	D-3-GLU	D-3-ARA	M-3-GAL	M-3-ARA	M-3-GLU	Po-3-GLU	Po-3-HEX	Po-3-ARA	Pt-3-GAL	Pt-3 ARA
Blueberry	7.14± 0.02	ND	2.71± 2.66	53.88± 2.14	ND	30.04± 2.14	69.38± 4.54	34.49± 2.14	3.79± 0.20	ND	7.71± 1.03	3.61± 0.15	43.23± 1.77	19.30± 0.73
DSCF3984-4	42.36± 1.32	14.81± 0.12	60.24± 0.67	28.53± 1.82	6.43± 0.21	37.92± 1.23	ND	6.65± 0.31	6.84± 0.12	11.09± 0.38	8.14± 0.59	14.5± 0.35	12.53± 0.57	ND
DSCF3986-5	10.74± 0.74	7.55± 0.41	3.15± 0.23	8.44± 0.49	5.19± 0.05	2.21± 0.22	ND	ND	1.26± 0.05	2.89± 0.10	1.93± 0.09	ND	2.11± 0.17	ND
9JOA3679-2	21.09± 0.02	0.77± 0.01	20.77± 0.72	111.02± 4.14	ND	49.45± 2.23	ND	5.09± 0.32	11.84± 0.69	ND	5.02± 0.27	3.4± 0.10	ND	ND
9JOA3678-1	41.94± 0.02	8.02± 4.58	17.76± 1.4	108.07± 16.71	ND	7.82± 0.30	ND	1.86± 0.72	6.05± 0.84	7.02± 1.94	7.37± 0.28	ND	ND	ND
9JOA3682-3	8.84± 0.02	13.3± 0.96	19.05± 1.49	38.29± 2.43	50.57± 2.82	82.78± 6.01	ND	ND	7.96± 1.15	ND	11.46± 0.77	3.68± 1.26	ND	ND

Huckleberries contained markedly higher concentrations of cyanidins compared to blueberries (Table 1), in the form of cyanidin-3-O-glucoside (C-3-GLU), cyanidin-3-O-galactoside (C-3-GAL) and cyanidin-3-O-arabinoside (C-3-ARA). C-3-ARA has only been detected in high concentrations in extracts from chokeberries (Aronia melanocarpia) (Wen et al., 2020) and in low amounts in cranberries (Brown and Shipley, 2011). C-3-ARA has also been detected in other wild berries (Mieres-Castro et al., 2019; Sánchez-Gavilán et al., 2021), and has been suggested to possess beneficial health properties through mitochondrial regulation (Jung et al., 2022). C-3-GLU and C-3-GAL are common anthocyanins in berries and other foods (Bellocco et al., 2016; Liang et al., 2021; Solverson et al., 2022) and their health benefits have been studied more extensively (Chen et al., 2022; Gan et al., 2020; Liang et al., 2021; Tan et al., 2019). Therefore, with two to ten-fold the amount of cyanidin derivatives compared to blueberries, huckleberries can be considered as excellent sources of dietary cyanidins with health protective effects.

Three of the huckleberries accessions (9JOA3679-2, 9JOA3678-1, 9JOA3682-3) were characterized by higher delphinidins concentrations, while the two other accessions (DSCF3984-4, DSCF3986-5) were characterized by higher peonidins concentrations (Table 1). It should be noted that other anthocyanins were also highly variable in concentrations across the different accessions, suggesting that either or both the genetic background or the environmental conditions determine the huckleberries anthocyanins profile. Delphinidins have been extensively studied in combination with cyanidins for their potential to mitigate the postprandial dysmetabolism, endotoxemia, alterations of glycemia and lipidemia, and redox and insulin signaling associated with high-fat consumption (Cremonini et al., 2019, 2022a, 2022b; Daveri et al., 2018; Oteiza et al., 2023). This suggests that the anthocyanins profile of the huckleberries accessions 9JOA3679-2, 9JOA3678-1, and 9JOA3682-3 may be particularly beneficial in terms of potential nutrition and health outcomes. Peonidins have received less attention for health research (Ren et al., 2021; Semmarath et al., 2022), but peonidins levels are only slightly higher than in blueberries, so the two other accessions are mostly different in terms of their cyanidins and malvidins levels.

3.4. Anthocyanins in other wild berries

Elderberries were characterized by the presence of unique cyanidins: Cyanidin-3-sambubioside-5-glucoside, Cyanidin-3-O-sambubioside (glucose-xylose), Cyanidin-coumaroyl-sambubioside and Cyanidin-3-p-coumaroyl-sambubioside as well as different petunidins (Table 2). This unique anthocyanin profile is in line with published phenolic profiles from cultivated (Domínguez et al., 2020; Liu et al., 2022; Pinto et al., 2017) and wild blue elderberries (Uhl et al., 2022). No other anthocyanins were detected except for minute amounts of Delphinidin-3-O-rutinoside (see Table 3).

Table 2.

Flavonol profiles in other wild berries (Q: Quercetin; K: Kaempferol) expressed in mg/100g of fresh berries(N = 3 for each accession).

	Elderberries	Service berries	Oregon grapes	Snow berries
Q-rutinoside	3.43 ± 1.52	11.64 ± 1.03	142.52 ± 16.5	180.56 ± 24.29
Q-arabinoglucoside	ND	36.92 ± 4.19	ND	11.71 ± 1.64
Q-hexoside	33.55 ± 1.87	ND	39.94 ± 10.79	8.04 ± 2.05
Q-galactoside	0.83 ± 0.15	68.34 ± 16.77	ND	ND
Q-glucoside	ND	20.16 ± 4.29	ND	ND
K-hexoside	ND	3.53 ± 1.02	39.52 ± 8.31	328.83 ± 64.1

Table 3.

Anthocyanins levels in elderberries, service berries and Oregon grapes expressed in mg/100g of fresh berries(N = 3 for each accession). GAL: Galactoside; GLU: Glucoside; ARA: Arabinoside; HEX: Hexoside; C-S: Coumaroyl-Sambubioside; 3S-S: Sambubioside; RUT: Rutinoside.

		Elderberries	Service berries	Oregon grapes
Cyanidins	C-3-S-5-GLU	75.66 ± 5.60	ND	ND
	C-3S-S	22.03 ± 1.99	ND	ND
	C-C-S	141.37 ± 10.37	ND	ND
	C-3-GAL	0.83 ± 0.15	113.11 ± 16.78	ND
	C-3GLU	ND	8.30 ± 1.75	ND
	C-3-ARA	15.88 ± 1.54	7.89 ± 1.38	ND
	C-3-RUT	ND	ND	40.12 ± 1.67
Delphinidins	D-3-GAL	ND	ND	1.82 ± 0.22
	D-3-GLU	ND	ND	66.12 ± 1.16
	D-3-RUT	7.3 ± 0.12	ND	ND
Malvidinins	M-3-GLU	ND	ND	32.17 ± 3.19
	M-3-RUT	ND	ND	16.24 ± 0.58
Peonidins	Po-3-GLU	ND	ND	21.50 ± 1.54
	Po-3-GAL	ND	ND	4.12 ± 0.06
Petunidins	Pt-3,5-GLU	17.66 ± 0.76	ND	ND
	Pt-3-GLU	76.58 ± 2.29	ND	ND
	Pt-3-RUT	7.76 ± 0.79	ND	31.96 ± 0.38

Service berries anthocyanins only contained cyanidins, with a large predominance of cyanidin-3-galactoside. This extremely high amount of cyanidin-3-galactoside could make service berries a convenient source for selective extraction.

Oregon grapes harbored relatively low amounts of cyanidin-3-rutinosideand no other cyanidins. Remarkably, Oregon grapes contain significant levels of Delphinidins, Malvidinins, Peonidins and Petunidins.

4. Conclusions

To the best of our knowledge, this is the first report of comprehensive polyphenol profiles for each wild berry. Our data confirms that wildly sourced berries display comparable, if not more elevated concentrations of polyphenols that commercially grown species; which is likely due to higher environmental stress. Remarkably, while closely related genetically, huckleberries have distinct profiles than blueberries, in particular in their anthocyanins content. Since specific anthocyanin classes are emergingly associated with different metabolic and physiologic outcomes, wild berries represent a valuable approach to diversify berry and associated phytochemical intake for maximized nutritional benefits. Since huckleberries are known for large phenotypic variations associated to their environment, repeated analyses in different locations and different years would be required to better understand the factors leading to specific phenolic compounds production. Correlating phenolic compounds with phenotype can also help with better assessing fruit ripeness for harvest.

Wild accessions of elderberry berries appear to harbor similar phenolic profiles than commercial ones, with especially high anthocyanin levels. The other wild berries tested are sparsely used but exhibited intriguing phenolic profiles. Snow berries could be valued as sources of phenolic acids for dietary supplements. The Mahonia aquifolia berries (“Oregon grapes”) showed the most remarkable phenolic contents by far, but more extensive collecting would be needed to determine if these properties are consistently observed in berries found in different areas. M. aquifolia is popularly used as an ornamental in many countries, thus determining if more domesticated environmental conditions limit the production of phenolic compounds would be of interest.

Funding

This research was supported by institutional funds (University start-up package to FC). his research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

CRediT authorship contribution statement

Jerome Higbee: Conceptualization, Methodology, Formal analysis, Resources, Writing – original draft. Cindi Brownmiller: Formal analysis, Resources. Patrick Solverson: Writing – original draft, Writing – review & editing. Luke Howard: Formal analysis, Resources. Franck Carbonero: Conceptualization, Validation, Resources, Writing – original draft, Writing – review & editing, Supervision.

Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Franck Carbonero reports a relationship with USDA-ARS that includes: funding grants. Patrick Solverson reports a relationship with National Institute of Food and Agriculture that includes: funding grants. Patrick Solverson reports a relationship with Sustainable Agriculture Research & Education that includes: funding grants. Luke Howard reports a relationship with National Institute of Food and Agriculture that includes: funding grants.

Handling Editor: Dr. Yeonhwa Park

Data availability

Data will be made available on request.