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We have studied the effect of resveratrol on lipoperoxidation and antioxidant enzyme activity level in the brain of healthy rats. When intraperitoneally administered, resveratrol significantly and dose dependently decreased brain malondialdehyde level. Resveratrol also increased in a dose-dependent way brain superoxide dismutase, catalase and peroxidase activities. Optimal effect on antioxidant enzyme and lipoperoxidation products were obtained with resveratrol concentration of 12.5 mg/kg body wt. Native polyacrylamide gel electrophoresis analysis of antioxidant isoenzymes revealed that resveratrol up regulated at least two acidic superoxide dismutase isoforms called A(1) and A(2), two basic isoforms called B(1) and B(2). Resveratrol also up regulated two catalase isoforms and a broad peroxidase band corresponding to several isoforms. All these findings suggest that resveratrol is able to cross the blood brain barrier and exerts potent antioxidant features. Resveratrol also exerts neuroprotective properties by up regulating several detoxifying enzymes, most of which are iron proteins.

Salvia officinalis L. is a medicinal plant containing several compounds with important pharmacological activity. In this study, we investigated the effects of water deficit (moderate and severe water deficits) on the contents of total and individual polyphenols of the aerial parts. Also, we studied the effect of drought on the antioxidant activity of methanolic extracts. Our results showed that water deficiency, as estimated by the decrease in water potential, resulted in a reduction of the biomass, plant height and total chlorophyll contents. In general, drought increased the level of total and individual polyphenols and this increase was more pronounced under moderate water deficit. These findings suggest that S. Officinalis is a sensitive species and that a severe water deficit could result in a decline in the activity of enzymes involved in the biosynthesis of phenolic compounds. On the other hand, our results showed an enhancement of reducing power and the radical scavenging activity as assessed using the DPPH assay with increasing stress severity. Finally, the evaluation of the chelating capacity of the extracts was found to be altered significantly under severe treatment by 39.71%. Based on these results, it seems that drought tolerance of S. officinalis is related to the capacity of the plant to modulate its phenolics in order to face to oxidative stress caused by water limiting conditions.

Cuminum cyminum L. roots, stems and leaves, and flowers were investigated for their essential oils, total phenolics, flavonoids, and tannins contents, individual phenolic compounds, and antioxidant activities. The essential oil was investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), whereas identification and quantification of individual target polyphenolic compounds was performed by reversed-phase high-performance liquid chromatography (RP-HPLC). Essential oil yields were 0.03% in roots, 0.1% in stem and leaves, and 1.7% in flowers. Major components of the oils were bornyl acetate (23%), α-terpinene (34%), and γ-terpinene (51%) in roots, stems and leaves, and flowers, respectively. In all C. cyminum organs, total phenolics content ranged from 11.8 to 19.2 mg of gallic acid equivalents per gram of dry weight (mg of GAE/g of DW). Among the polyphenols studied, 13 were identified in roots, 17 in stem and leaves, and 15 in flowers. The major phenolic compound in the roots was quercetin (26%), whereas in the stems and leaves, p-coumaric, rosmarinic, trans-2-dihydrocinnamic acids and resorcinol were predominant. In the flowers, vanillic acid was the main compound (51%). The antioxidant activities of C. cyminum essential oils and acetone extracts obtained from the three organs were assessed using four tests [1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene/linoleic acid, reducing power, and chelating power assays]. The acetone extract of flowers was strongly effective as a DPPH radical scavenger, lipid peroxidation inhibitor, and reducing agent, with IC(50) values of 4, 32, and 8 μg/mL, respectively. Moreover, the acetone extract of stems and leaves showed the highest chelating power. However, the essential oils exhibited moderate activities in the different tests.