Geraniin and amariin, ellagitannins from Phyllanthus amarus, protect liver cells against ethanol induced cytotoxicity.

Ethanol mediated free radical generation plays an important role in the pathogenesis of liver injuries and alcoholic liver diseases. In the present study two ellagitannins namely geraniin and amariin isolated from Phyllanthus amarus were examined for their ability to protect mouse liver slices against ethanol induced toxicity and possible mechanism of its protection. Oxidative stress markers such as, lipid peroxidation, protein carbonyl formation, amount of 8-hydroxy-2-deoxyguanosine and antioxidant enzymes levels were measured using specific biochemical assays.

Oral intake of purple passion fruit peel extract reduces pain and stiffness and improves physical function in adult patients with knee osteoarthritis.

Knee osteoarthritis (OA) is a common degenerative joint disorder and a major cause of pain and disability. The hypothesis tested in this study was that the passion fruit peel extract (PFP), a flavonoid-rich dietary supplement, would reduce symptoms due to knee OA. Thirty-three OA patients were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design.

Radioprotective properties of polyphenols from Phyllanthus amarus Linn.

Radioprotective activity of pure compounds isolated from the plant Phyllanthus amarus was studied using rat liver mitochondria and pBR322 plasmid DNA as an in vitro model system. These compounds were ellagitannins namely amariin, 1-galloyl-2,3-dehydrohexahydroxydiphenyl (DHHDP)-glucose, repandusinic acid, geraniin, corilagin, phyllanthusiin D, and flavonoids namely rutin, and quercetin 3-O-glucoside. The activity was then correlated with their hydroxyl and superoxide radical scavenging activity.

Antioxidant activity of some polyphenol constituents of the medicinal plant Phyllanthus amarus Linn.

Phyllanthus amarus Linn is a widely distributed tropical medicinal plant highly valued for its therapeutic properties. The antioxidant activity of some of its principal constituents, namely amariin, 1-galloyl-2,3-dehydrohexahydroxydiphenyl (DHHDP)-glucose, repandusinic acid, geraniin, corilagin, phyllanthusiin D, rutin and quercetin 3-O-glucoside were examined for their ability to scavenge free radicals in a range of systems including 2,2-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azobis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS)/ferrylmyoglobin, ferric reducing antioxidant power (FRAP) and pulse radiolysis. In addition, their ability to protect rat liver mitochondria against oxidative damage was determined by measuring the ROO* radical induced damage to proteins and lipids and *OH radical induced damage to plasmid DNA.

Isolation and characterisation of procyanidins from Rumex obtusifolius.

An acetone:water (7:3) extract obtained from the leaves of Rumex obtusifolius was fractionated into procyanidin oligomer and polymer fractions using a linear gradient and a simple step method on Sephadex LH-20. The chemical characteristics of the procyanidin fractions were studied by 13C-NMR spectroscopy, acid-catalysed degradation in the presence of benzyl mercaptan, matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) MS and electrospray ionisation (ESI) MS. The 13C-NMR showed that the polymer fraction consisted predominantly of procyanidin polymers, some with galloyl groups attached.

Antioxidant mechanisms of polyphenolic caffeic acid oligomers, constituents of Salvia officinalis.

Caffeic acid, rosmarinic acid and oligomers of caffeic acid with multiple catechol groups are all constituents of Salvia officinalis. Their antioxidant potential was investigated with regard to their radical scavenging activity and the stability and structure of the intermediate radicals. Pulse-radiolytic studies revealed very high rate constants with hydroxyl radicals.

Pulse radiolysis, electron paramagnetic resonance spectroscopy and theoretical calculations of caffeic acid oligomer radicals.

Seven representative compounds isolated from Salvia officinalis, among them caffeic acid, the dimer rosmarinic acid and oligomers of caffeic acid, were investigated with regard to their antioxidant potential both expressed by the radical scavenging activity and the stability and structure of the intermediate radicals. Pulse-radiolytic investigation revealed very high rate constants with both hydroxyl and azide radicals. Evidence from kinetic modelling calculations suggested unusual complex behavior due to the presence of both O(4)- and O(3)-semiquinones and - in two cases - formation and decay of a hydroxyl radical adduct at the vinyl side chain.

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.

Polyphenolics of Salvia--a review.

Salvia is an important genus widely cultivated and used in flavouring and folk medicines. The genus has attracted great interest so much so that it has been the subject of numerous chemical studies. It is a rich source of polyphenols, with an excess of 160 polyphenols having been identified, some of which are unique to the genus.