Hydrogen sulfide is involved in the chilling stress response in Vitis vinifera L.

Hydrogen sulfide (H₂S) is an important signaling molecule involved in several stress-resistance processes in plants, such as drought and heavy metal stresses. However, little is known about the roles of H₂S in responses to chilling stress. In this paper, we demonstrated that chilling stress enhance the H₂S levels, the H₂S synthetase (L-/D-cysteine desulfhydrase, L/DCD) activities, and the expression of L/DCD gene in <em>Vitis vinifera</em> L. ‘F-242’. Furthermore, the seedlings were treated with sodium hydrosulfide (NaHS, a H₂S donor) and hypotaurine (HT, a H₂S scavenger) at 4°C to examine the effects of exogenous H₂S on grape. The results revealed that the high activity of superoxide dismutase and enhanced expression of <em>VvICE1</em> and <em>VvCBF3</em> genes, but low level of super oxide anion radical, malondialdehyde content and cell membrane permeability were detected after addition of NaHS. In contrast, HT treatment displayed contrary effect under the chilling temperature. Taken together, these data suggested that H₂S might be directly involved in the cold signal transduction pathway of grape.

Phenolic Compounds from Eucalyptus Gomphocephala with Potential Cytotoxic and Antioxidant Activities

Two new phenolic compounds, 2,4,6-trihydroxy-5-methyl-acetophenone 2- O-β-D-glucopyranoside (3), and benzyl alcohol 7- O-(3’,4’,6’-tri- O-galloyl)-β-D-glucopyranoside (8), together with eight known phenolic compounds, were isolated from the 70% aqueous acetone extract of Eucalyptus gomphocephala DC. (Myrtaceae). The isolated compounds were elucidated based on their 1H, 13C, DQF-COSY, selective 1D-TOCSY, HSQC, and HMBC NMR spectroscopic; and ESIMS data. The antioxidant effect of the phenolic compounds was tested using 1,1-diphenyl-2-picrylhydrazyl (DPPH.), hydroxyl radical and super oxide anion radical scavenging assays. The cytotoxicity of the isolated compounds was evaluated using HeLa cell line.

Chemical Composition and Bioactivity of Pleiogynium timorense (Anacardiaceae)

A liquid chromatography-diode array detection-electrospray ionization mass spectrometric (HPLC–PDA-ESI/MS/MS) method was used for the analysis of the phenolic composition of the ethanolic extract obtained from the leaves of Pleiogynium timorense (DC.) Leenh. Twenty compounds were detected and tentatively characterized. In addition, further phytochemical investigations of the extract resulted in the isolation of twelve major phenolic compounds. Evidence of the structures of these compounds was obtained based on the interpretation of the UV, 1H NMR, 13C NMR and DQF-COSY spectral data. The antioxidant effect of the ethanolic extract was examined in vitro using 1,1-diphenyl-2-picrylhydrazyl (DPPH.) and super oxide anion radical scavenging assays. DPPH. radical scavenging activity was observed for the extract, with an IC50 of 21.9 μg/mL, while its super oxide anion scavenging activity was less pronounced, with an IC50 of 123.5 μg/mL The ethanolic extract showed significant hypoglycemic, antioxidant and anti-inflammatory properties. This study suggests that the ethanolic extract of Pleiogynium timorense is a potential source of antioxidant compounds, relatively non-toxic, and have possible beneficial health effects.

Scavenging of Reactive Oxygen Species by a Urinary Preparation

In the present paper, the antioxidant properties of a preparation of human urine (PHU) were evaluated by studying the ability of this drug to react with relevant biological oxidants such as super-oxide anion radical ( O 2·-) and hydroxyl radical ( OH ·). In addition, its effect on lipid peroxidation was investigated in vitro and ex vivo. PHU is not a good scavenger of O2·-. However, it react rapidly with OH· radicals with a second-order rate constant of 2.8 × 109/M/sec. The studies on rat brain homogenates showed that PHU had an inhibitory effect, which was dependent on its concentration and the magnitude of lipid peroxidation. Ex vivo studies also showed that oral administration of PHU increased the antioxidant capacity of plasma from rats. The ability of PHU to scavenge free radicals suggests that this drug may be potentially useful in counteracting free radical-mediated diseases.