Characterisation of anthocyanins in the black soybean (Glycine max L.) by HPLC-DAD-ESI/MS analysis

The aim of this study was to isolate and identify the anthocyanins in the black seed coated soybean (cv. Cheongja 3, Glycine max (L.) Merr.) using reverse phase C-18 open column chromatography and high-performance liquid chromatography (HPLC) with diode array detection and electro spray ionization/mass spectrometry (DAD-ESI/MS) analysis, respectively. Anthocyanins were extracted from the coat of black soybeans with 1% TFA in methanol, isolated by RP-C-18 column chromatography, and their structures elucidated by 1D and 2D NMR spectroscopy. The isolated anthocyanins were characterised as delphinidin-3-O-glucoside (3), cyanidin-3-O-glucoside (5), petunidin-3-O-glucoside (6), pelargonidin-3-O-glucoside (7) and cyanidin (9). Furthermore, four minor anthocyanins were detected and identified as catechin-cyanidin-3-O-glucoside (1), delphinidin-3-O-galactoside (2), cyanidin-3-O-galactoside (4), and peonidin-3-O-glucoside (8) based on the fragmentation patterns of HPLC-DAD-ESI/MS analysis.     

Characterisation and preliminary bioactivity determination of Berberis boliviana Lechler fruit anthocyanins

Berberis boliviana Lechler is a member of the Berberidaceae family that has a small edible red-purple berry. The plant is native to the Peruvian Andes and contains high amounts of anthocyanin pigments. The monomeric anthocyanin content, determined by a pH-differential method, was 7/100 g of seedless berries. Pigments were characterised by HPLC coupled to a photodiode array (PDA) and mass spectrophotometer (MS) detectors. Five aglycones and ten anthocyanins were found and identified as petunidin-3-glucoside (24.4%), delphinidin-3-glucoside (24.1%), malvidin-3-glucoside (22.1%), cyanidin-3-glucoside (10.2%), petunidin-3-rutinoside (7.15%), malvidin-3-rutinoside (4.9%), cyanidin-3-rutinoside (3.8%), delphinidin-3-rutinoside (2.6%), peonidin-3-glucoside (1.1%), and peonidin-3-rutinoside (0.9%).     

Characterisation of phenolic phytochemicals and quality changes related to the harvest times from the leaves of Korean purple perilla (Perilla frutescens)

The objective of this study was to investigate the profiles of phenolic phytochemicals in the leaves of Korean purple perilla (cv. Bora, Perilla fructescens) using reversed-phase C₁₈ column chromatography and HPLC with DAD-ESI/MS analysis. Changes in their contents were also the first reported through eight different harvest times during two months. They were characterised as five anthocyanins and three phenolic acids including cyanidin-3,5-di-O-glucoside (1), cyanidin-3-O-glucoside (2), cyanidin-3-O-(6-O-caffeoyl)glucoside-5-O-glucoside (3), cyanidin-3-O-(6-O-coumaroyl)glucoside-5-O-glucoside (4), cyanidin-3-O-(6-O-coumaroyl)glucoside (5), caffeic acid (6), rosmarinic acid (7), and rosmarinic acid methylester (8). Significant differences were observed between individual and total phytochemical contents, especially, cyanidin-3-O-(6-O-coumaroyl)glucoside-5-O-glucoside (4) and rosmarinic acid (7) exhibited the predominant constituents. Among different harvest times, the highest content was found with 82.473 mg/g on 21st September, while the lowest was 39.000 mg/g on 17th August. These results may be useful in determining the optimal harvest time at which phenolic phytochemicals reaches a maximum level in mid-September.     

Chemical characterisation of anthocyanins in tamarillo (Solanum betaceum Cav.) and Andes berry (Rubus glaucus Benth.) fruits

The anthocyanin composition of tamarillo (Solanum betaceum Cav., red variety) and Andes berry (Rubus glaucus Benth.) was determined by HPLC–PDA and HPLC–ESIMS. From the anthocyanin-rich extracts (AREs), pure compounds (1–7) were obtained by MLCCC (multilayer countercurrent chromatography) and further preparative HPLC, and their unequivocal structures were obtained by 1D and 2D NMR analyses. The new anthocyanin delphinidin 3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside-3′-O-β-d-glucopyranoside, as well as the known cyanidin-3-O-rutinoside, pelargonidin-3-O-rutinoside, and delphinidin-3-O-rutinoside were identified as constituents of tamarillo fruit. Although the anthocyanin composition of Andes berry had been reported before in the literature, the unequivocal structure elucidation of the major compound, cyanidin-3-O-α-l-rhamnopyranosyl-(1 → 6)-O-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside, was achieved for the first time.     

Identification,characterisation, and quantification of phenolic compounds in the antioxidant activity-containing fraction from the seeds of Korean perilla (Perilla frutescens) cultivars

The present research was the first to investigate phenolic compound profiles and antioxidant properties in the seeds of various perilla (Perilla frutescens) cultivars. The 80% methanol extract (50 μg/ml) of this species showed potent antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. Phenolic compounds were characterised by nuclear magnetic resonance (NMR) spectroscopy, and ultra performance liquid chromatography with photodiode array detector and electrospray ionisation/mass (UPLC-PDA-ESI/MS) analysis. Nine compounds were elucidated as caffeic acid-3-O-glucoside (1), caffeic acid (2), luteolin-7-O-glucoside (3), apigenin-7-O-glucoside (4), rosmarinic acid-3-O-glucoside (5), rosmarinic acid (6), luteolin (7), apigenin (8), and chrysoeriol (9). The individual and total phenolic contents were remarkably different, especially rosmarinic acid-3-O-glucoside (5) and rosmarinic acid (6) which were the predominant compounds (>95%) in all perilla cultivars. Additionally, Yeupsil cultivar exhibited the highest phenolic content (5029.0 μg/g) and antioxidant activity, whereas the lowest was shown by Dasil (2138.7 μg/g). Therefore, these results suggest that antioxidant effects of perilla seeds are correlated with phenolic contents.     

A new phragmalin-type limonoid and anti-inflammatory constituents from the fruits of Swietenia macrophylla

The fruit of Swietenia macrophylla is commercially used in healthcare products for the improvement of blood circulation and skin condition. A new phragmalin-type limonoid, 6-O-acetyl-3′-demethylswietephragmin E (1), has been isolated from the fruit of S. macrophylla, together with 16 known compounds. The structure of this new compound was determined through spectroscopic and MS analyses. 6-O-Acetyl-3′-demethylswietephragmin E (1), 3,6-O,O-diacetylswietenolide (5), 3-O-tigloylswietenolide (6), 3-O-tigloyl-6-O-acetylswietenolide (8), swietemahonin E (9), and 6-O-acetylswietemahonin G (10) exhibited inhibition (IC₅₀ ? 35.7 μM) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP).     

Kumquat (Fortunella japonica Swingle) juice: Flavonoid distribution and antioxidant properties

The flavonoids composition of kumquat (Fortunella japonica) crude juice, obtained from uripe and ripe fruits, were investigated by reverse-phase LC-DAD-ESI-ITMS analysis. Thirteen compounds (C- and O-glycosyl flavonoids) were identified. Acacetin 3,6-di-C-glucoside (1), vicenin-2 (2), lucenin-2 4′-methyl ether (3) narirutin 4′-O-glucoside (4) and apigenin 8-C-neohesperidoside (5) were identified for the first time in kumquat juice. Furthermore, we report on the remarkable antioxidant properties of crude juice, of selected flavonoids fractions and of the main component, phloretin 3′,5′-di-C-glucoside (6).     

Identification of antioxidants from rhizome of Davallia solida

Davallia solida rhizome has long been used as an herb tonic to treat osteoporosis, arthralgia, and arthritis. The aqueous extract of D. solida rhizome contains a high content of phenolic compounds [210.8 ± 4.6 mg catechin equivalents (CE)/g dry weight] and shows a strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (IC₅₀ = 15.93 ± 1.21 μg dry weight/ml). Further solvent partition of the aqueous extract yielded chloroform, n-butanol, and water layers. Among them, n-butanol layer has the highest phenol content (806.3 ± 12.3 mg CE/g dry weight) and DPPH scavenging potential (IC₅₀ = 3.93 ± 0.31 μg dry weight/ml). Isolation and purification from the n-butanol layer identified 12 compounds. They included four new compounds: 3′-O-p-hydroxybenzoylmangiferin (1), 4′-O-p-hydroxybenzoylmangiferin (2), 6′-O-p-hydroxybenzoylmangiferin (3), and 3-O-p-hydroxybenzoylmangiferin (4); as well as eight known compounds: mangiferin (5), 2-C-β-d-xylopyranosyl-1,3,6,7-tetrahydroxyxanthone (6), 4β-carboxymethyl-(−)-epicatechin (7), 4β-carboxymethyl-(−)-epicatechin methyl ester (8), eriodictyol (9), eriodictyol-8-C-β-d-glucopyranoside (10), icariside E₅ (11), and icariside E₃ (12). DPPH scavenging and Trolox equivalent antioxidant capacity (TEAC) analyses revealed that the most potent antioxidants are 1, 2, and 3, which exerted more than triple activity as compared with the positive controls, α-tocopherol and Trolox.     

Isolation and structure elucidation of phenolic compounds from Cyclopia subternata Vogel (honeybush) intact plant and in vitro cultures

In the presented work, an insight was made into the polyphenolic composition of intact plant material and in vitro cultures of indigenous South African plant Cyclopia subternata Vogel (honeybush). Ethyl acetate fractions of methanol extracts were separated by means of gravity column chromatography and/or semipreparative HPLC on two serially connected monolithic RP-18 columns. The structures of the isolated compounds were determined by means of 1D and 2D NMR techniques and additionally confirmed by LC-DAD-ESI-MS. Apart from the previously described honeybush components, that is mangiferin (1), scolymoside (2), hesperidin (3) and narirutin (4), three additional compounds: iriflophenone 3-C-β-glucoside (benzophenone) (5), phloretin 3′,5′-di-C-β-glucoside (dihydrochalcone) (6), and isorhoifolin (flavone) (7) were identified for the first time in the herb of C. subternata. Additionally, three isoflavone glucosides, namely calycosin 7-O-β-glucoside (8), rothindin (9) and ononin (10), which had not been previously reported in Cyclopia plants, were identified in the callus of the above species. As far as the authors are concerned, this is the first report on the presence of benzophenone and dihydrochalcone derivatives in Cyclopia genus.     

New flavonol glycosides from Barbeya oleoides Schweinfurth

Three new flavonol glycosides, 3′,5′ dimethoxymyricetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (1), 3′-methoxyquercetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (2) and 3′-methoxyqurecetin-6″-O-α-l-rhamnopyranosyl (1–6) β-d-glucopyranoside (3), have been isolated from the aerial part of Barbeya oleoides Schweinf., along with twelve known compounds, uvaol (4), ursolic acid (5), corosolic acid (6), arjunolic acid (7), β-sitosterol-3-O-β-d-glucoside (8), (+)–catechin (9), (-)-epicatechin (10), isorhamnetin-4′-O-glucoside (11), arjunglucoside I (12), d-(-)-bornesitol (13), gallocatechin (14) and epigallocatechin (15). Compounds 4–15 were isolated for the first time from Barbeyaceae. Structure elucidation of compounds 1–3 was based on MS and NMR data. The ethyl acetate extract of the stems as well as compounds 5, 6, 14 and 15 showed significant antimicrobial activity, while the ethanol extracts of leaves, stems and compounds 4, 7, 8, 13–15 have dose-dependent spasmolytic action.     

Polyphenols from longan seeds and their radical-scavenging activity

Five previously uncharacterised polyphenols, ethyl gallate (2), 1-β-O-galloyl-d-glucopyranose (3), methyl brevifolin carboxylate (4), brevifolin (5) and 4-O-α-l-rhamnopyranosyl-ellagic acid (8), and three previously identified polyphenols, gallic acid (1), corilagin (6) and ellagic acid (7), were isolated from longan seeds. Their structures were identified by spectroscopic and chemical methods including HRESIMS and NMR. Eight polyphenols exhibited scavenging activity towards DPPH radicals with SC₅₀ values of 0.80–5.91 μg/ml and towards superoxide radicals with SC₅₀ values of 1.04–7.03 μg/ml. The radical-scavenging activity of the newly characterised polyphenols was comparable to that of gallic acid, corilagin and ellagic acid.     

Identification of phenolic antioxidants from Sword Brake fern (Pteris ensiformis Burm.)

Sword Brake fern (Pteris ensiformis Burm.) is one of the most common ingredients of traditional herbal drinks in Taiwan. In an effort to identify antioxidants from the aqueous extract of Sword Brake fern (SBF), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity-guided isolation was employed. Three new compounds, kaempferol 3-O-α-l-rhamnopyranoside-7-O-[α-d-apiofuranosyl-(1-2)-β-d-glucopyranoside] (1), 7-O-caffeoylhydroxymaltol 3-O-β-d-glucopyranoside (3) and hispidin 4-O-β-d-glucopyranoside (4), together with five known compounds, kaempferol 3-O-α-l-rhamnopyranosid-7-O-β-d-glucopyranoside (2), caffeic acid (5), 5-O-caffeoylquinic acid (6), 3,5-di-O-caffeoylquinic acid (7) and 4,5-di-O-caffeoylquinic acid (8) were isolated and determined on the basis of spectroscopic analyses. HPLC with UV detector was further employed to analyze the content of each compound in SBF based on the retention time by comparison with isolated pure compounds. It was found that the most abundant phenolic compound was compound 3, followed by compounds 7 and 4. The di-O-caffeoylquinic acids (7 and 8) have the strongest DPPH scavenging potential with IC₅₀ around 10 μM and the highest Trolox equivalent antioxidant capacity (TEAC) about 2 mM. This data indicates that SBF is rich in phenolic antioxidants.     

Three new flavanonol glycosides from leaves of Engelhardtia roxburghiana, and their anti-inflammation, antiproliferative and antioxidant properties

The ethyl acetate fraction of the leaves of Engelhardia roxburghiana Wall exhibited strong anti-inflammatory, anti-proliferative, and antioxidant activities. From this fraction, three new flavanonol glycosides: (2R, 3R)-3,5,7,4′-tetrahydroxyflavanonol-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (1), (2R, 3R)-3,5,7,3′,4′-pentahydroxyflavanonol-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (2), (2R, 3R)-3,5,7,3′,4′-pentahydroxyflavanonol-3-O-(3″-O- p-(E)-coumaroyl)-α-l-rhamnopyranoside (3), were isolated. The structures of these compounds were elucidated based on spectroscopic, and chemical analyses. The anti-inflammatory activities of 1-3 were examined as their inhibitory abilities on the expression of IL-1β, TNF-α, MCP-1, and COX-2 mRNA, in lipopolysaccharide-stimulated mouse J774A.1 macrophage cells. At the concentration of 50 μM, 2 and 3 significantly reduced the IL-1β expression, while 1 induced its expression contrarily. Meanwhile, 1 and 3 exhibited significant inhibition of TNF-α expression at the concentration of 10 μM, while 2 could achieve weak but significant inhibition at 50 μM. Furthermore, 1-3 did not suppress the mRNA expression of MCP-1 and COX-2. Compounds 1-3 showed significant anti-proliferative effect in Hep G2 cells. 3 showed the most potent anti-proliferative effect in HT-29 human colon cancer cells, while 1 and 2 had no inhibition. In addition, 1 and 2 exhibited antioxidant activities. The ORAC values of 1 and 2 were 12.8 and 17.0 mmol TE/g and the HOSC values of 1 and 2 were 14.4 and 16.0 mmol TE/g, respectively.     

Anti-melanogenesis properties of quercetin- and its derivative-rich extract from Allium cepa

In an effort to find a new whitening agent, we have found that the methanol extract of the dried skin of Allium cepa showed inhibition of melanin formation. Bioassay-guided fractionation led to the isolation of quercetin (1) and quercetin 4’-O-β-glucoside (3) from A. cepa as the inhibitors of melanin formation in B16 melanoma cells with IC₅₀ values of 26.5 and 131 μM, respectively. In addition, we evaluated the effect of some quercetin derivatives, such as isoquercitrin (2), quercetin 3,4’-O-diglucoside (4), rutin (5) and hyperin (6) on B16 melanoma cells. These quercetin derivatives did not show any inhibition of melanin formation. Furthermore, the ORAC values of compounds 1–6 were 7.64, 8.65, 4.82, 4.32, 8.17 and 9.34 μmol trolox equivalents/μmol, respectively. Dried skin of red onion showed inhibitory activity against melanin formation in B16 melanoma cells, as well as antioxidant properties.     

Characterisation of flavonoids in Orostachys japonicus A. Berger using HPLC–MS/MS: Contribution to the overall antioxidant effect

Orostachys japonicus cultivated in the Republic of Korea was analysed for flavonoid content via HPLC coupled to MS/MS. Amongst 16 compounds that were characterised, eight flavonoids and one alkaloid were characterised for the first time: two procyanidin dimer gallate isomers (1 and 2), epigallochatechin-3-gallate (3), two procyanidin dimer digallate isomers (4 and 9), quercetin 3-O-rhamnosyl-7-O-glucoside (6), myricetin 3-O-glucoside (10), kaempferol (16) and N¹,N⁵,N¹⁰-tri-p-(E,E,E)-coumaroylspermidine (15). The identified compounds were quantified by HPLC–UV/DAD. The antioxidant activity of the O. japonicus flavonoids was determined via 2,2-diphenyl-1-picrylhydrazyl radical (DPPH^•), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS^•+) and nitric oxide radical (NO^•) scavenging assays.     

Phenolic constituents from the flower buds of Lonicera japonica and their 5-lipoxygenase inhibitory activities

Thirteen phenolic constituents, luteolin (1), protocatechuic acid (2), caffeic acid (3), flavoyadorinin-B (4), 4,5-dicaffeoylquinic acid (5), luteolin 7-O-β-d-glucopyranoside (7), 3,5-dicaffeoylquinic acid methyl ester (8), methyl chlorogenate (9), quercetin 3-O-β-d-glucopyranoside (10), 3,5-dicaffeoylquinic acid (11), rhoifolin (12), chlorogenic acid (13), and a novel phenolic glucoside benzoate, vanillic acid 4-O-β-d-(6-O-benzoylglucopyranoside) (6), were isolated from the flower buds of Lonicera japonica. Flavoyadorinin-B (4) was isolated for the first time from a Caprifoliaceae plant. The structures of 1–13 were determined on the basis of chemical and spectroscopic evidence. These compounds were screened for their 5-lipoxygenase inhibitory activity. Only luteolin (1) showed significant inhibitory activity against 5-LOX-catalysed leukotriene production.     

Phenolic-rich extract from the Costa Rican guava (Psidium friedrichsthalianum) pulp with antioxidant and anti-inflammatory activity. Potential for COPD therapy

The potential therapeutic effects of Costa Rican guava (Psidium friedrichsthalianum) extracts for chronic obstructive pulmonary disease were examined. The ethyl acetate fraction displayed the highest antioxidant activity, as compared to the hexane, chloroform, and n-butanol fractions, as well as the crude extract. This fraction was evaluated for its anti-inflammatory activity response relationship against interleukin-8 (IL-8) and inhibition of matrix metalloproteinase-1 (MMP-1) expression before and after treatment with cigarette smoke. The ethyl acetate fraction exhibited inhibitory activity against IL-8 production and MMP-1 expression, showing the most potent inhibitory activities in both assays at 100 μg/mL, and nine compounds (1–9) were found. Phenolic compounds 1-O-trans-cinnamoyl-β-d-glucopyranose (2), ellagic acid (3), myricetin (4), quercitrin (7), and quercetin (9) were identified using standard compounds or literature reports from related species. Compounds 1, 5, 6, and 8 were tentatively identified as 1,5-dimethyl citrate (1), sinapic aldehyde 4-O-β-d-glucopyranose (5), 3,3′,4-tri-O-methylellagic acid-4′-O-d-glucopyranoside (6), and 1,3-O-diferuloylglycerol (8), All nine compounds are reported for the first time in Costa Rican guava.     

Spirostane and cholestane glycosides from the bulbs of Allium nigrum L

A phytochemical investigation of the fresh bulbs of Allium nigrum L. led to the isolation of new spirostane-type glycosides as two inseparable isomer mixtures, nigrosides A1/A2 (1a/1b) and nigrosides B1/B2 (2a/2b), two new cholestane-type glycosides, nigrosides C and D (3 and 4), together with the known compounds, 25(R,S)-5α-spirostan-2α,3β,6β-trio1-3-O-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (5a/5b) and 25(R,S)-5α-spirostan-2α,3β,6β-trio1 3-O-β-d-glucopyranosyl-(1 → 2)-O-[4-O-(3S)-3-hydroxy-3-methylglutaryl-β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (6a/6b), isolated from this plant for the first time. All structures were elucidated mainly by spectroscopic analysis (1D and 2D NMR experiments, FABMS, HRESIMS) and by comparison with literature data. Cytotoxicity of the isolated compounds was assessed against human colon carcinoma (HT-29 and HCT 116) cell lines. Compounds 5a/5b and 6a/6b were found to be the most active with IC₅₀ values 1.09 and 2.82 μM against HT-29 and 1.59 and 3.45 μM against HCT 116, respectively.     

Determination of chemical variability of phenolic and monoterpene glycosides in the seeds of Paeonia species using HPLC and profiling analysis

A rapid, sensitive, and accurate HPLC-DAD method was developed and validated for simultaneous determination of one phenolic glycoside and seven monoterpene glycosides, including 1-O-β-d-(4-hydroxybenzoyl)glucose (1), pyridylpaeoniflorin (2), (8R)-piperitone-4-en-9-O-β-d-glucopyranoside (3), oxypaeoniflorin (4), 6′-O-β-glucopyranosylalbiflorin (5), albiflorin (6), β-gentiobiosylpaeoniflorin (7), and paeoniflorin (8), in 44 batches of peony seeds from nine Paeonia species collected from different areas. Using the optimised method, separations were conducted with a YMC-pack ODS-A column with water/formic acid and methanol as the mobile phase. All eight analytes demonstrated good linearity (r² > 0.9993). The recoveries, measured at three concentration levels, varied from 98.20% to 103.81%. Six compounds including 1 and 4–8 occur ubiquitously in all the seeds of nine Paeonia species, and compounds 2 and 3 showed undetectable levels or very low content in several samples. The seed samples were classified into several groups, which coincide with the taxonomy of Paeonia at the section level. Peony seed might be a useful resource in developing new herbal or food products.