‘Cyanidin volumetric index’ and ‘chromaticity coordinates ratio’ to characterize red raspberry (Rubus idaeus)

The object of this work is presented in a larger research project concerning ‘New indexes to evidence the nutritional quality of small fruits’ in progress at the Analytical Food Research Laboratories, University of Milan. The present paper contains data that contribute to the analytical characterization of 12 varieties of red raspberry through the high-performance liquid chromatography determination of the aglycon ‘cyanidin’ derived from chemical hydrolysis of berries. Even more interesting results are the proposal of the ‘cyanidin volumetric index’, by which it is possible to compare different red raspberry varieties with higher meaningfulness. A new possible correlation between the ratio of chromaticity coordinates ‘a/b’ and the cyanidin content of red raspberries has been identified.     

Phenolic acids,flavonols and anthocyanins in Corema album (L.) D. Don berries

Phenolic compounds of Corema album (Ericaceae) wild edible berries were determined by LC–DAD–MS/MS. Fifteen compounds were identified and quantified, including phenolic acids (2268.1 ± 229.2 mg/kg of dried weight, DW) such as chlorogenic and neochlorogenic acids, flavonols (638.3 ± 80.1 mg/kg DW) including quercetin 3-O-hexoside and rutin, and the anthocyanins (19. 6 ± 2.4 mg/kg DW) cyanidin 3-O-glucoside, cyanidin 3-O-pentoside and delphinidin 3-O-hexoside. Phenolic acids, the main phenolic compounds in this fruit, were fractionated into their free and bound forms, and analysed by GC–MS after hydrolysis. Eleven compounds (benzoic, salicylic, t-cinnamic, p-hydroxybenzoic, vanillic, gentisic, syringic, p-coumaric, gallic, ferulic and caffeic acids) were identified on the basis of GC retention times and simultaneously recorded mass spectra, namely caffeic, benzoic, ferulic and vanillic acids as the major phenolic acids in Corema album berries.     

Composition of anthocyanins in mulberry and their antioxidant activity

Anthocyanins in the fruits of mulberry (Morus alba L.) were extracted and separated by high-speed counter-current chromatography (HSCCC) using a biphasic solvent system composed of methyl tert-butyl ether–n-butanol–acetonitrile–water–trifluoroacetic acid (1:3:1:5:0.001) to yield five anthocyanins: cyanidin 3-O-(6″-O-α-rhamnopyranosyl-β-d-glucopyranoside) (C3RG), cyanidin 3-O-(6″-O-α-rhamnopyranosyl-β-d-galactopyranoside) (C3RGa), cyanidin 3-O-β-d-glucopyranoside (C3G), cyanidin 3-O-β-d-galactopyranoside (C3Ga) and cyanidin 7-O-β-d-glucopyranoside (C7G), respectively. The five compounds were identified by ESI–MS and one/two-dimensional NMR spectra. The antioxidant activity of crude mulberry anthocyanins (CMA), C3G, C3Ga, C7G, C3RG and C3RGa was investigated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method. The results showed that CMA, C3G, C3Ga, C3G and C7G have higher scavenging ability on DPPH. At the concentration of 0.10 mg/mL, the DPPH radical scavenging rates of C3G, C3Ga and C7G were about 88% of vitamin C, while C3RG and C3RGa were about 60% of it. CMA had the same DPPH radical scavenging rate as vitamin C or the five anthocyanin monomers when the concentration reached 0.40 mg/mL, which shows that CMA is an excellent antioxidant agent.     

Anthocyanin profile and antioxidant capacity of black carrots (Daucus carota L. ssp. sativus var. atrorubens Alef.) from Cuevas Bajas,Spain

The present work deals with the study of the anthocyanin profile of two different black carrots (Daucus carota L. ssp. sativus var. atrorubens Alef.) cultivars, associated with Antonina and Purple Haze varieties, from Cuevas Bajas (Málaga, Spain) and some of their antioxidant features. The main anthocyanins detected by LC–MS were found to correspond to five cyanidin-based anthocyanins: cyanidin 3-xylosylglucosylgalactoside, cyanidin 3-xylosylgalactoside and the sinapic, ferulic and coumaric acids derivative of cyanidin 3-xylosylglucosylgalactoside. The anthocyanins present in the black carrots were essentially acylated and their levels were found to correspond to 25% and 50% of the total phenolic content for the Purple Haze and Antonina varieties, respectively. Moreover, the reducing capacity of the two black carrots extracts (86.4 ± 8.0 and 182.0 ± 27 μM TE/100 g fw) and the radical scavenging ability (17.6 ± 9.0 and 240.0 ± 54.0 μM TE/100 g fw) expressed in Trolox equivalents units were determined. The antioxidant features of the black carrot extracts were shown to be significantly higher than those of orange carrots used herein for comparison. Overall, this work highlights the Cuevas Bajas black carrots as rich sources of anthocyanins with significant antioxidant capacities and good nutritional value.     

Anthocyanins from the fruits of Rubus croceacanthus and Rubus sieboldii,wild berry plants from Okinawa,Japan

Anthocyanins from the fruits of Rubus croceacanthus and Rubus sieboldii, wild berries from Okinawa, Japan, were extracted using 80% methanol containing 0.5% acetic acid, and the extracts were separated by a DIAION HP-20 column. The major anthocyanins were purified by preparative HPLC and their structures were determined by NMR and MS spectrometry. Cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside were identified from R. croceacanthus, and their contents were 81.44 ± 1.01 mg and 170.02 ± 4.36 mg/100 g fresh weight, respectively. Pelargonidin-3-O-glucoside and pelargonidin-3-O-rutinoside were identified from R. sieboldii, and their contents were 10.04 ± 0.34 mg and 15.08 ± 0.48 mg/100 g fresh weight, respectively. An ORAC assay indicated that the two Okinawan wild berries, especially R. croceacanthus, had potent antioxidant activity compared to raspberry (Rubus idaeus).     

Diversity of anthocyanins and other phenolic compounds among tropical root crops from Vanuatu, South Pacific

To study the composition and amounts of phenolic compounds in ten tropical root crop species consumed daily worldwide and particularly in South Pacific, acidified aqueous extracts were analyzed. Among 134 samples, 78 components were found. Among total peaks detected from these fractions, 3 anthocyanins (peonidin-caffeoyl-feruloylsophoroside-5-glucoside, petunidin-3-glucoside and pelargonidin-3-glucoside), 5 flavonols (hyperoside, isorhamnetin-3-glucoside, kaempferol-3-glucoside, quercetin-3-glucopyranoside and quercetin-3′-glucoside,6′-acetate), 3 flavanols (catechin, epicatechin and epicatechin-3-gallate), and 3 phenolic acids (caffeic acid, chlorogenic acid and 3,5-dicaffeoylquinic acid) were tentatively identified by HPLC-DAD. Although many compounds remain to be identified, results suggest that these tropical root crops are good sources of anthocyanins and phenolic compounds. The greater yam (Dioscorea alata) had the highest anthocyanin content (up to 93.3 mg CGE/100 g DW), while taro (Colocasia esculenta) had the widest range of flavonols (up to 326.7 mg QGE/100 g DW). Cultivars of these staples should be exploited in breeding programs for the development of varieties with enhanced health and nutritional benefits.     

Effect of olive cultivar on bioaccessibility and antioxidant activity of phenolic fraction of virgin olive oil

Aim

This study aims to characterize the phenolic profile and antioxidant capacity of seven monovarietal virgin olive oils (VOOs) and evaluate their in vitro gastrointestinal stability.

Methods

‘Picual’, ‘Blanqueta’, ‘Sevillana’, ‘Habichuelero’, and ‘Chetoui’ olive cultivars were selected for VOO extraction. The oils were subjected to in vitro digestion. The recovery index (RI) of phenolic compounds after each digestion step and the bioaccessibility index (BI) were evaluated. In addition, the antioxidant activity of the bioaccessible fraction (BF) of VOOs was determined by DPPH, ABTS, and ORAC assays, as well as by studying the intracellular reactive oxygen species in Caco-2 cells.

Results

Differences were found in the composition of phenolic compounds in VOOs depending on cultivars. During the digestive process, important losses of phenolic compounds were observed between the buccal and duodenal steps, unlike HTy and Ty, which presented increased recovery due to the hydrolysis of secoiridoid derivatives. Differences in the bioaccessibility of phenolic compounds were found between varieties of VOOs. ‘Sevillana’ VOO had the highest total bioaccessibility (36%), followed by the ‘Picual’ (19%), ‘Chetoui’ (17%), ‘Habichuelero’ (10%), and ‘Blanqueta’ (8%) varieties. The BF of all the varieties of VOO showed similar radical ABTS scavenging capacity, ‘Chetoui’, and ‘Blanqueta’-BF having the highest radical DPPH scavenging capacity, and ‘Habichuelero’ and ‘Picual’-BF showing protective effects against the peroxyl radical measured by ORAC_FL assay. All VOO-BFs presented decreases in ROS levels in Caco-2 cells.

Conclusions

Our results suggest differences in the bioaccessibility of phenolics from diverse VOO varieties, which could lead to different biological properties. Therefore, this study represents a first step toward the development of novel dietary strategies focusing on the phenolic supplementation of different VOOs to preserve human health.

     

Effects of Black Raspberries and Their Constituents on Rat Prostate Carcinogenesis and Human Prostate Cancer Cell Growth In Vitro

Abstract

Prostate cancer patients often use dietary supplements, such as black raspberries, which are a rich source of compounds with antioxidant and anticancer activity, particularly on gastrointestinal cancers. Feeding black raspberries inhibited mammary cancer induction in rats and growth of cancer cells in nude mice, indicating systemic bioavailability of bioactive compounds. We tested whether feeding black raspberries and its constituents would inhibit prostate cancer development. However, we did not find preventive effects in two rat prostate carcinogenesis models, even though the berry anthocyanin metabolite protocatechuic acid was detectable in their prostates. Black raspberry extract, the anthocyanin cyanidin-3-rutinoside and protocatechuic acid did not inhibit prostate cancer cell growth in vitro, but ellagic acid and its urolithin A metabolite did at high concentrations. Prostate cancer cell migration was not affected by these agents nor was growth in soft agar, except that ellagic acid reduced colony formation at physiological concentrations and protocatechuic acid at high concentrations. Low bioavailability of bioactive berry compounds and metabolites may limit exposure of tissues such as the prostate, since we found that cyanidin-3-rutinoside was not bioavailable to prostate cancer cells, but its aglycone cyanidin was and inhibited their growth. Thus, black raspberries are unlikely to prevent prostate cancer.     

Identification and quantification of polyphenolic compounds in ten pear cultivars by UPLC-PDA-Q/TOF-MS

The aim of this study was to identify and compare phenolic acids, flavan-3-ols and procyanidins, flavonol glycosides, flavones and hydroquinones in different cultivars of pear. Pear fruits (Pyrus communis L.) of ten cultivars (‘Bonkreta Williamsa’, ‘Carola’, ‘Dicolor’, ‘Faworytka’, ‘Hortensia’, ‘Konferencja’, ‘Lukasówka’, ‘Nojabrska’, ‘Radana’ and ‘Uta’) were used in this study. Sixty-five phenolic compounds, including 26 phenolic acids, 22 flavan-3-ols and procyanidins, 15 flavonols, 1 flavone, and 1 hydroquinone, were determined in the examined samples using the ultra-performance liquid chromatography photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) method. Major differences were found in the phenolic profiles of investigated cultivars. The ‘Radana’ cultivar exhibited the highest total phenolics content (894.9 mg/kg FW) and was characterized by the highest concentration of phenolic acids (503.1 mg/kg FW) and arbutin (70.8 mg/kg FW).     

'Cyanidin volumetric index' and 'chromaticity coordinates ratio' to characterize red raspberry (Rubus idaeus)

The object of this work is presented in a larger research project concerning 'New indexes to evidence the nutritional quality of small fruits' in progress at the Analytical Food Research Laboratories, University of Milan. The present paper contains data that contribute to the analytical characterization of 12 varieties of red raspberry through the high-performance liquid chromatography determination of the aglycon 'cyanidin' derived from chemical hydrolysis of berries. Even more interesting results are the proposal of the 'cyanidin volumetric index', by which it is possible to compare different red raspberry varieties with higher meaningfulness. A new possible correlation between the ratio of chromaticity coordinates 'a/b' and the cyanidin content of red raspberries has been identified.     

Discrimination of five Greek red grape varieties according to the anthocyanin and proanthocyanidin profiles of their skins and seeds

The knowledge of grapes phenolic content is proven to be critical for the vinification process and the improvement of wine quality. This study was undertaken to determine the phenolic composition and to employ the phenolic profile as a varietal discrimination tool in five Greek red grape varieties. Ninety grape samples from two seasons (2017 and 2018) were analyzed after extraction with organic solvents. Their proanthocyanidin profile, expressed as percentages of flavan-3-ols, was determined in both skins and seeds by employing phloroglucinolysis followed by HPLC-UV and MS detection, and anthocyanin profile was identified only in the skin extracts by HPLC-UV. Significant differences were observed in proanthocyanidin and anthocyanin profiles of skin extracts between the samples of different varieties, but not in seeds. (-)-Epicatechin was the main subunit in Mandilaria, Kotsifali, Agiorgitiko and Xinomavro grapes while (-)-epigallocatechin gallate in Mavrotragano. Malvidin-3-O-glucoside was the predominant pigment in all grape samples analyzed with the exception of Kotsifali skin extracts, where peonidin-3-O-glucoside was the most abundant anthocyanin. In addition, Mavrotragano skin extracts were the richest in delphinidin and petunidin-3-O-glucosides, while Agiorgitiko and Xinomavro contained the highest amount of malvidin-3-O-glucoside. The results underline the significance of the skin phenolic composition as a tool for the discrimination of the Greek red grape varieties.     

Profiling of phenolic compounds using UPLC–MS for determining the geographical origin of green coffee beans from Ethiopia

A total of 100 samples of green coffee (Coffea arabica L.) beans from the major producing regions of Ethiopia were studied using ultra performance liquid chromatography–mass spectroscopy to determine if the phenolic content could be linked to their geographical origins for authentication purposes. Principal component analysis allowed the most discriminating compounds to be identified. Based on their concentrations, 3-O-caffeoylquinic and 4,5-O-dicaffeoylquinic acids were found to be characteristic markers for Northwest and East (Harar) region coffees, respectively. Sub-regional coffee types from West, except Jimma B, could be distinguished by their 3,5-O-dicaffeoylquinic to 4,5-O-dicaffeoylquinic acid concentration ratios, while Yirgachefe coffees from South could be distinguished by their 4,5-O-dicaffeoylquinic to 3,4-O-dicaffeoylquinic acid concentration ratios. Linear discriminant analysis provided a classification model with recognition and prediction abilities of 91% and 90%, respectively, at regional level, and 89% and 86%, respectively, at sub-regional level. This is important for the detection of fraud, including the selling of inferior Ethiopian coffees under the label of the more expensive Harar coffees.     

Development and validation of ultrasound assisted extraction (UAE) and HPLC-DAD method for determination of polyphenols in dry beans (Phaseolus vulgaris)

An analytical method for extraction and quantitative determination of the main phenolic compounds (hydroxycinnamic acids and derivatives, anthocyanins and flavonols) in dry beans (Phaseolus vulgaris) is described. The best extraction conditions were: 100% sonication amplitude, 10.3 min extraction, 46% ethanol, 1.5 g dry bean flour and 30 mL of solvent. The developed method was validated in terms of accuracy and precision. Good linearity was obtained, with correlation coefficients exceeding 0.999 and the quantification limits ranged from 0.25 μg/g (p-coumaric acid) to 1.38 μg/g (kaempferol). The accuracy ranged between 88 and 92% and the reproducibility of the method was always < 5.8% (RSD). The method was applied to a set of 17 accessions with different phenotypes. Results showed a greater presence, in all cases, of ferulic acid derivatives, compared to the sinapic acid and p-coumaric acid derivatives. Except for the white variety Xana, flavonoids were detected in all samples. Higher levels of anthocyanins were detected in Black Turtle Soup, a black bean, characterized by a higher content of delphinidin 3-O-glucoside, petunidin 3-O-glucoside and malvidin 3-O-glucoside. The flavonols showed a remarkable diversity, the 3-glucoside derivatives being the most abundant in all samples.     

Comprehensive analysis of phenolic compounds and abscisic acid profiles of twelve native Canadian berries

Wild berries, integral parts of North American Natives’ traditional nutrition, are a rich source of phytochemicals involved in the prevention of metabolic syndrome. Although phenolic compounds are generally considered to be the functional components in fruits, the identification of specific compounds in relation to this beneficial activity remains to be uncovered. With the long-term goal of establishing the contribution of phytochemical compounds to their beneficial health effects, we investigated in a comprehensive manner the composition of twelve native Canadian berries: Saskatoon berry, alpine bearberry, chokeberry, black crowberry, honeysuckle, chokecherry, cloudberry, elderberry, lowbush blueberry, alpine blueberry, lingonberry and highbush cranberry. All harvested in the province of Quebec, these fruits were analyzed for their phenolic composition (anthocyanins, flavonols, flavan-3-ols, phenolic acids, proanthocyanidins and ellagitannins) and their content in abscisic acid derivatives (cis- and trans-ABA, abscisic acid-glucose ester, 7′-hydroxy-abscisic acid, neo-phaseic acid, phaseic acid and dihydrophaseic acid). Over 60 different phenolic compounds were identified and quantified in berries. Along with the characterization of abscisic acid, this study reports for the first time a complete characterization of proanthocyanidins in these fruits, highbush cranberry presenting the highest content of this class of compounds.     

Quantitative comparison of phytochemical profile,antioxidant, and anti-inflammatory properties of blackberry fruits adapted to Argentina

The phytochemical profile by HPLC-TOF-MS of three blackberry cultivars (‘Jumbo’, ‘Black Satin’ and ‘Dirksen’), adapted to the central-east of Argentina, was determined. The antioxidant capacity by DPPH and FRAP assays, and the effect of the blackberry extracts on lipopolysaccharide (LPS)-induced nitric oxide (NO) production, reactive oxygen species (ROS) production, and biomarkers of inflammation were also evaluated. ‘Dirksen’ fruits exhibited the highest vitamin C content (24 and 14% higher than values found in ‘Black Satin’ and ‘Jumbo’, respectively). However, ‘Jumbo’ and ‘Black Satin’ fruits presented higher total phenolic contents (more than 15%) than ‘Dirksen’. Cyanidin-3-O-glucoside was the main polyphenolic compound quantified in all samples. ‘Jumbo’ and ‘Black Satin’ cultivars exhibited higher antioxidant capacity, and significantly reduced the release of ROS. The mRNA expression levels of cyclooxygenase-2 (Cox-2) and interleukin-6 (IL-6) were reduced consistently (more than 30%) by extracts of both cultivars, and showed slight suppressions on NO production. However, effective inhibition in the gene expression of interleukin-1β (IL-1β) and nitric oxide synthase (iNOS) was not observed by any extract. These results suggest the potential of blackberries cultivars ‘Black Satin’ and ‘Jumbo’ to contribute to a healthy diet, based on their higher polyphenol content, providing higher antioxidant and anti-inflammatory properties.     

Comprehensive profiling of α-glucosidase inhibitors from the leaves of Rubus suavissimus using an off-line hyphenation of HSCCC,ultrafiltration HPLC-UV-MS and prep-HPLC

The leaves of Rubus suavissimus (also called “Chinese sweet tea”) is used not only as a beverage tea and food additive but also as a folk herbal medicine for the treatment of diabetes mellitus. To systematically investigate its material foundation of efficacy for treating diabetes, herein, a hyphenated strategy by off-line coupling high-speed countercurrent chromatography, ultrafiltration HPLC-UV-MS and prep-HPLC was developed. And thus, α-glucosidase inhibitors from Rubus suavissimus leaves was comprehensively profiled, purified and characterized. As a result, twenty-six compounds were identified as potential α-glucosidase inhibitors and favorably isolated by prep-HPLC. Their structures were identified via UV, MS, and ¹H-NMR. Notably, fourteen compounds, including protocatechuic acid (1), myketin (3), epicatechin (4), vanillic acid (6), apigenin (11), catechin (12), ferulic acid (15), luteolin (16), 3, 3′-di-O-methylellagic acid (17), chlorogenic acid (19), 3, 3′-di-O-methylellagic acid-4′-O-β-D-glucoside (20), cinnamic acid (21), syringate (24) and ethylbrevifolin-carboxylate (25), were reported in leaves of Rubus suavissimus for the first time. In addition, α-glucosidase inhibitory activities of compounds 1–26 were evaluated, and eighteen compounds exhibited stronger α-glucosidase inhibitory activities than acarbose (IC₅₀ value at 214.24 ± 3.48 μg/mL, positive control). The results indicated that the proposed method is a highly efficient strategy for comprehensive profiling and purification of bioactive target compounds, including both major and minor components, from natural products.     

Analysis of Anthocyanins in Plasma for Determination of their Bioavailability

Anthocyanins show a great potential as natural food antioxidants. This study tried to identify the anthocyanins from elderberry (Sambucus nigra) in human blood plasma and to determine their bioavailability in humans. Using a restricted access phase for removal of the proteins and enrichment of the anthocyanins it was possible to analyse the substances in plasma. From the four known anthocyanins present in elderberry the two main components (cyanidin-3- O -glucoside and cyanidin 3- O -sambubioside) could be analysed quantitatively. Using a high-fat diet, it could be shown that the anthocyanins appear 2 h after ingestion and reach a maximum value 1 later. Within a few hours the anthocyanins are eliminated from the plasma. The amount of anthocyanins found in the plasma is well below 1% of the ingested substances.     

Rubus occidentalis: The black raspberry—its potential in the prevention of cancer

Rubus occidentalis is a black-fruited raspberry originating from North America. Its popularity and demand has been growing over the years, as studies outline its high anthocyanin and ellagitannin content and significance for human health. Interaction between chemical composition and pharmacological activity, mechanisms of action at cellular and molecular levels are all active areas of study. The vast majority of research concerning black raspberries is focused on chemoprevention and anticancer effects. This review summarizes the data on chemical composition and anticancer activity of black raspberry fruits throughout the years.     

Polyphenol metabolic diversity of Chinese peach and nectarine at thinned and ripe stages by UPLC-ESI-Q-TOF-MS combined with multivariate statistical analysis

Peach and nectarine fruits are rich in phenolic compounds, which differ with the varieties and maturity. This study profiled the polyphenol metabolites in 7 Chinese peach and nectarine varieties at thinned and ripe stages by HPLC and UPLC-ESI-Q-TOF-MS. A total of 58 phenolic metabolites were identified in peach and nectarine. Neochlorogenic acid, catechin and chlorogenic acid were the dominant polyphenols in 7 varieties at both thinned and ripe stages. Regarding fruits at the thinned stage, phenolic acids were the major metabolic markers that distinguished 7 different peach and nectarine varieties, whereas flavonoids were the main metabolites differentiated the ripe fruit. Moreover, 3-p-coumaroyl quinic acid, 1-caffeoylquinic acid, myricetin, and kaempferol-3-o-rutinoside were the vital phenolic markers that differentiated thinned young fruit from the ripe one. There were significant differences in the polyphenol metabolic profile in different peach and nectarine varieties in different maturity stages. This work would provide a reference for further peach and nectarine phenolic metabolites investigation.     

Metabolite profiling of pigments from acid-hydrolysed persimmon (Diospyros kaki) extracts by HPLC-DAD/ESI-MSn analysis

Pigments profile from acid-hydrolysed “Rojo Brillante” persimmon (Diospyros kaki) extracts was elucidated by high-performance liquid chromatography with diode array detection coupled to tandem mass spectrometry analysis with positive electrospray ionization (HPLC-DAD-ESI⁺/MSⁿ). In total, seventeen anthocyanidin-based aglycones were tentatively identified: four free anthocyanidins (delphinidin, petunidin, cyanidin and peonidin) and, for the first time in a naturally derived extract, thirteen 3-O-galloyl-flavanol-anthocyanidin adducts (dimers formed by a galloylated (epi)catechin or (epi)gallocatechin with an anthocyanidin). Furthermore, evidences of non-galloylated flavanol-anthocyanidin adducts were also found in the samples studied. The developed methodology, which included the use of a routine three-dimensional ion trap, represents an affordable solution to achieve detailed metabolite profiles of foodstuffs.