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Microwave-assisted extraction of embelin from Embelia ribes.

A rapid and efficient microwave-assisted extraction (MAE) process for the selective extraction of embelin from Embelia ribes was developed. Solvent selection, microwave energy input and solid loading were optimized. The rate of extraction and purity of embelin depended upon the solvent used and exposure time to microwaves. Maximum MAE was achieved in acetone with total yield of 92% (w/w) embelin with 90% (w/w) purity with 1% (w/v) raw material loading at 150 W power level in 80 s. Non-polar solvents, such as hexane and dichloromethane, were not effective for the selective extraction of embelin.

Benzoquinones↗

High-performance liquid chromatography (HPLC) analysis of phenolic compounds in berries with diode array and electrospray ionization mass spectrometric (MS) detection: ribes species.

High-performance liquid chromatography combined with diode array and electrospray ionization mass spectrometric (MS) detection was used to study phenolic compounds in berries of black, green, red, and white currants (Ribes spp.). UV-visible spectrometry was a valuable tool for the identification of the class of the phenolic compound, whereas MS and MS-MS fragmentation data were useful for further structural characterization. Distinct similarities were found in the relative distribution of conjugated forms of phenolic compounds among the four currants. Phenolic acids were found mainly as hexose esters. Flavonol glycosides and anthocyanin pigments were mainly found as 3-O-rutinosides and second as 3-O-glucosides. However, cyanidin 3-O-sambubioside and quercetin hexoside-malonate were notable phenolic compounds in red currant. Flavonol hexoside-malonates were identified and quantified in the berries of currants for the first time.

Anthocyanins↗

Anthocyanin-flavanol condensation products from black currant (Ribes nigrum L.).

Putative flavanol-anthocyanin condensation products were detected in a polyphenol-rich concentrate from black currant (Ribes nigrum L.). These compounds had UV-vis spectra similar to those of delphinidin-3-O-rutinoside and cyanidin-3-O-rutinoside, but eluted before all previously described anthocyanins on reversed phase HPLC. Mass spectrometric data indicated that they were rutinoside derivatives of novel aglycons 304 amu greater than delphinidin and cyanidin, respectively. The compounds were partly purified by semipreparative HPLC and gave MS and MS2 spectra consistent with anthocyanin rutinosides covalently linked to epigallocatechin or gallocatechin. These compounds are similar in structure to compounds thought to influence color and quality in red wines and strawberry juice products. There was also evidence for the presence of a range of other flavanol-anthocyanin condensation products. The compounds were present at differing levels in juices of 10 black currant varieties, which were roughly correlated to the content of the parent anthocyanins. The flavanol-anthocyanin products were present in polyphenol-enriched concentrates obtained by solid phase extraction, in commercially produced concentrates, and in fresh extracts of black currants. This suggests that the compounds were not artifacts formed during concentration or purification. However, differences in their comparative contents may be related to the lability of the parent anthocyanins during processing. Although present at low levels, the flavanol-anthocyanin products may influence color or quality parameters of black currant juices, and they may confer enhanced stability to the biological activities reported for their anthocyanin parents.

Anthocyanins↗

High-performance liquid chromatography analysis of black currant (Ribes nigrum L.) fruit phenolics grown either conventionally or organically.

Black currants (Ribes nigrum L.) contain a diverse range of phenolics and possess a high antioxidant activity, which makes them an interesting target for the functional food industry. In this study, phenolic profiles of organically and conventionally grown black currant fruits, collected from commercial farms within a climatically similar area, were compared. Compounds were identified using UV/vis and mass spectroscopy techniques and quantified with high-performance liquid chromatography equipped with UV/vis detection. Several different conjugates of hydroxycinnamic acids, flavonols, and anthocyanins were quantified. Statistically significant differences between farms were found for almost all compounds. Differences between the highest and the lowest measured values of major phenolic compounds of different phenolic classes ranged from 24 to 77%. Principal component analysis quite effectively separated farms from each other but did not cluster them according to cultivation technique. Thus, it was concluded that the biochemical quality of organically grown black currant fruits does not differ from those grown conventionally.

Anthocyanins↗

Inhibitory effects of proanthocyanidins from Ribes nigrum leaves on carrageenin acute inflammatory reactions induced in rats.

BACKGROUND: The anti-inflammatory effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, were analysed using carrageenin-induced paw oedema and carrageenin-induced pleurisy in rats. RESULTS: Pretreatment of the animals with PACs (10, 30, 60 and 100 mg/kg, i.p.) reduced paw oedema induced by carrageenin in a dose and time-dependent manner. PACs also inhibited dose-dependently carrageenin-induced pleurisy in rats. They reduced (A) lung injury, (B) pleural exudate formation, (C) polymorphonuclear cell infiltration, (D) pleural exudate levels of TNF-alpha, IL-1beta and CINC-1 but did not affect IL-6 and IL-10 levels. They reduced (E) pleural exudate levels of nitrite/nitrate (NOx). In indomethacin treated rats, the volume of pleural exudate was low, its content in leukocytes and its contents in TNF-alpha, IL-1beta, IL-6 and IL-10 but not in NOx were reduced. These data suggest that the anti-inflammatory properties of PACs are achieved through a different pattern from those of indomethacin. CONCLUSION: These results suggest that the main mechanism of the anti-inflammatory effect of PACs mainly lies in an interference with the migration of the leukocytes. Moreover, PACs inhibited in vivo nitric oxide release.

Animals↗

New inhibitor against nuclear factor of activated T cells transcription from Ribes fasciculatum var. chinense.

Two new compounds were isolated from the stem and twigs of Ribes fasciculatum var. chinense and their structures were identified to be threo-(7S,8R)-1-(4-hydroxyphenyl)-2-[4-(E)-propenylphenoxy]-propan-1-ol (1), and 5,4'-dihydroxy-7-methoxyflavone-3-O-[alpha-L-rhamnopyranosyl(1-->3)-O-alpha-L-rhamnopyranosyl(1-->6)-O-beta-D-glucopyranoside] (2). With nine other known components, they were tested on inhibitory activity against nuclear factor of activated T cells (NFAT) transcription factor. Compound 1 showed a potent inhibitory activity (IC50=15.6 microM), while compounds 4, 5 and 9 showed moderate inhibitory activity (IC50 22.4, 24.5 and 25.7 microM, respectively).

DNA-Binding Proteins↗

Flavonoid glycosides and hydroxycinnamic acid esters of blackcurrants (Ribes nigrum). Phenolics of fruits 9.

The major flavonol glycosides of ripe blackcurrants (Ribes nigrum cv. Silvergieters Schwarze), myricetin 3-beta-D-glucopyranoside, rutin, and isoquercitrin, have been isolated in crystalline form. Analysis by thin-layer chromatography confirmed the occurrence of the 3-rutinosides and 3-glucosides of cyanidin and delphinidin. No free flavonoid aglycones could, however, be detected in the fresh berries. The major constituent fluorescing blue under ultraviolet light on paper and cellulose thin-layer chromatograms, was isolated and characterized as 1-O-caffeyl-beta-D-glucopyranose. Also isolated were 1-O-ferulyl- and 1-O-p-coumaryl-beta-D-glucopyranose. The occurrence fo hydroxycinnamyl-D-glucoses in blackcurrants does not appear to have been recognized previously.

Chromatography, Thin Layer↗

Cloning of cold-inducible dehydrin-like genes from the blackcurrant (Ribes nigrum L.) using RT-PCR.

A method is described for the identification of conserved genes in one plant species by using sequence information on internal motifs from well-characterized clones from another species. This sequence information is used to design primers for reverse transcriptase polymerase chain reaction (RT-PCR) and to design oligonucleotide probes to identify genuine positive amplification products. The approach was successfully used to clone cDNAs encoding cold-inducible dehydrin-like genes from the woody perennial blackcurrant, Ribes nigrum L. The strategy described can accelerate the cloning of heterologous cDNAs and is a convenient alternative to direct screening of cDNA libraries.

Amino Acid Sequence↗

Identification of (all-cis)-6,9,12,15-octadecatetraenoic acid in Ribes nigrum and fish oils: chemical and physical characterization.

In this report, we show that the non-conjugated octadecatetraenoic acid found in the oil of the seeds from Ribes nigrum is identical to the C18-polyunsaturated fatty acid previously isolated in a number of fish oils and seed oils. Evidence obtained from mass spectral data of its triazolopyridine derivative clearly indicates the presence of methylene-interrupted double bonds. Comparison with authentic material prepared by chemical synthesis provides further confirmation of the (all-cis)-6,9,12,15-octadecatetraenoic acid structure. The (all-cis)-4,8,12,15-structural arrangement erroneously attributed to this acid in several literature reports is thus definitely ruled out.

Carbon Isotopes↗

Comparative effects of total flavonoids extracted from Ribes nigrum leaves, rutin and isoquercitrin on biosynthesis and release of prostaglandins in the ex vivo rabbit heart.

Experiments were carried out on isolated rabbit hearts: PG biosynthesis was induced by administration into the coronary circulation of a single dose of arachidonic acid (100 micrograms) and the PGs synthesized and released in the heart effluent were detected by bioassays. Total flavonoids (TF) extracted from Ribes nigrum leaves and their 2 major components, rutin and isoquercitrin had neither spasmodic nor relaxing activity on rat stomach strip. They were not capable of inducing any biosynthesis and release of PG-like substances and did not act on PGE2 receptors. They inhibited both biosynthesis and release of PG-like substances: TF were more active than rutin and isoquercitrin: ID30 was 1.03 +/- 0.24 mg/ml for TF versus 3.75 +/- 0.24 mg/ml and 2.31 +/- 1.4 mg/ml for rutin and isoquercitrin respectively.

Animals↗

Anti-inflammatory evaluation of a hydroalcoholic extract of black currant leaves (Ribes nigrum).

A hydroalcoholic extract of black currant (Ribes nigrum) leaves was tested on carrageenan-induced rat paw oedema. Pharmacological activity was compared with indomethacin and niflumic acid using acute and chronic (21 or 28 days) oral treatment. Black currant extract and lyophilisate revealed significant anti-inflammatory activity comparable to that seen with the reference substances, but without their ulcerogenic potential, even at high doses during chronic treatment.

Animals↗

Wound healing activity of embelin isolated from the ethanol extract of leaves of Embelia ribes Burm.

Ethanol extract of the leaves of Embelia ribes Burm. (Myrsinaceae) and its isolated quinone compound embelin were screened for wound healing activity by excision, incision and dead space wound models on Swiss Albino Rats. Significant wound healing activity was observed in both ethanol crude extract (30 mg/ml) and the constituent treated groups. In embelin treated groups (4 mg/ml of 0.2% sodium alginate gel), epithelialization of the incision wound was faster with a high rate of wound contraction. The tensile strength of the incision wound was significantly increased than the ethanol extract. In dead space wound model also the weight of the granulation was increased indicating increase in collagenation. The histological examination of the granulation tissue of embelin treated group showed increased cross-linking of collagen fibers and absence of monocytes. The wound healing effect was comparatively evaluated with the standard skin ointment Framycetin.

Animals↗

Nigrumin-5-p-coumarate and nigrumin-5-ferulate, two unusual nitrile-containing metabolites from black currant (Ribes nigrum) seed.

Two novel nitrile-containing compounds, nigrumin-5-p-coumarate and nigrumin-5-ferulate, together with six known flavonoids, were isolated from the seed of black currant (Ribes nigrum). The chemical structures of nigrumin-5-p-coumarate and 5-ferulate were elucidated using NMR spectroscopy as 2-trans-p-coumaroyloxymethyl-4-beta-D-glucopyranosyloxy-2(E)-butenenitrile and 2-trans-feruloyloxymethyl-4-beta-D-glucopyranosyloxy-2(E)-butenenitrile, respectively.

Coumaric Acids↗

Combinations of Azadirachta indica and Cedrus deodara oil with piperonyl butoxide, MGK-264 and Embelia ribes against Lymnaea acuminata.

The binary and tertiary combinations of plant-derived molluscicides Azadirachta indica and Cedrus deodara oil with synergists MGK-264, piperonyl butoxide (PB) and fruit powder of Embelia ribes were used against the Lymnaea acuminata. It was observed that the toxic effects of these mixtures were time- and dose-dependent. The binary and tertiary mixtures of plant-derived molluscicides with synergists were more toxic with respect to the single treatment of the plant-derived molluscicides. Maximum synergistic action in binary and tertiary combinations was found in A. indica + C. deodara oil and A. indica+ PB + C. deodara in 1:7 and 1:5:7 ratio, respectively.

Animals↗

Non-destructive visualisation in three dimensions of freezing events in flowers of blackcurrant (Ribes nigrum L.) using spin-echo NMR microscopy.

Flowers of blackcurrant (Ribes nigrum L.) were subjected to freezing stress in vivo, and the resulting damage examined in three dimensions using a spin-echo nuclear magnetic resonance imaging sequence. Increased signal intensity was detected in the damaged flowers, particularly at the base of the style, in T2-weighted images. This is thought to be the result of intracellular freezing, which causes membrane damage and leakage of cellular contents. It is proposed that this represents the main site of damage within the flowers. The imaging of flowers of differing developmental ages showed larger increases in signal from fully open flowers after freezing damage compared with those in the initial stages of bud, suggesting that the enclosed nature of the flower buds may have a protective effect on the sensitive stylar base. The use of three-dimensional nuclear magnetic resonance imaging provides a rapid and effective means for the visualisation of freezing events within floral tissues; the effective resolution of the images enables greater accuracy and clarity in interpretation than hitherto possible in two dimensions.

Freezing↗

Characterization of Ribes rubrum callus cultured under low temperature.

Ribes rubrum callus was cultured at the temperature of 15 degrees C for 28 d. The contents of proteins and lipids in the callus cultured at 15 degrees C in a 28 d culture was significantly increased, being 1.1- and 1.2-fold, respectively, of those in callus cultured at 25 degrees C. Comparisons of the contents of monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG) and phosphatidyldiacylglycerol (PG) revealed that in the callus cultured at 25 degrees C, the content of MGDG was significantly decreased and those of the others significantly increased compared to those in callus cultured at 15 degrees C, in a 7 d culture. But, in a 28 d culture, the contents of these lipids in callus at 15 degrees C became the same as those in callus cultured at 25 degrees C. In regard to the protein composition, the contents of proteins 30 KDa or less in callus cultured at 15 degrees C in a 28 d culture were significantly higher than those in callus cultured at 25 degrees C. These consequences reflect that not only increase in the polyunsaturated fatty acid (PUFA) ratio of total fatty acid (TFA) with cold treatment reported by us previously [Hirano, M., J. Ferment. Bioeng., 83, 608-611 (1997)], but also an increase in low-molecular-weight protein content might be responsible for the cold-tolerance of R. rubrum callus.

Journal Article↗

Enzyme-assisted extraction of antioxidative phenols from black currant juice press residues (Ribes nigrum).

Enzymatic release of phenolic compounds from pomace remaining from black currant (Ribes nigrum) juice production was examined. Treatment with each of the commercial pectinolytic enzyme preparations Grindamyl pectinase, Macer8 FJ, Macer8 R, and Pectinex BE, as well as treatment with Novozym 89 protease, significantly increased plant cell wall breakdown of the pomace. Each of the tested enzyme preparations except Grindamyl pectinase also significantly enhanced the amount of phenols extracted from the pomace. Macer8 FJ and Macer8 R decreased the extraction yields of anthocyanins, whereas Pectinex BE and Novozym 89 protease showed no effect. A decrease in pomace particle sizes from 500-1000 microm to <125 microm increased the phenol yields 1.6-5 times. Black currant pomace devoid of seeds gave significantly higher yields of phenols than pomace with seeds and seedless wine pomace. Four selected black currant pomace extracts all exerted a pronounced antioxidant activity against human LDL oxidation in vitro when tested at equimolar phenol concentrations of 7.5-10 microM.

Anthocyanins↗

Anthocyanins from black currants (Ribes nigrum L.).

Fifteen anthocyanin structures are reported from an extract of black currant berries (Ribes nigrum L.). These are the 3-O-glucosides and the 3-O-rutinosides of pelargonidin, cyanidin, peonidin, delphinidin, petunidin, and malvidin, cyanidin 3-O-arabinoside, and the 3-O-(6' '-p-coumaroylglucoside)s of cyanidin and delphinidin. The anthocyanins were characterized by means of size exclusion chromatography, high-performance liquid chromatography, UV-visible spectroscopy, and electrospray mass spectrometry. The four main pigments (the 3-O-glucosides and the 3-O-rutinosides of delphinidin and cyanidin) made up >97% of the total anthocyanin content. The minor pigments were enriched from the extract by successive partition against ethyl acetate and by gel fractionation. These chromatographic steps were successfully used to isolate the acylated anthocyanins from the ethyl acetate layer and to separate cyanidin 3-O-arabinoside from the mixture of anthocyanins. The amounts of anthocyanin rutinosides were found to be higher than the amount of the corresponding glucosides for all detected pigments having the same aglycon moiety.

Anthocyanins↗