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Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV-A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV-A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV-A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue-light plant extracts revealed a higher proportion of the major flavonoid quercetin 3- O-α- l-arabinopyranosyl (1→2) α- l-rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity. [ABSTRACT FROM AUTHOR]

Lippia alba Mill. N. E. Br (Verbenaceae) is an aromatic shrub widely distributed in Brazil where the infusion of its leaves is used in folk medicine due to sedative and antispasmodic properties. This study presents data about quantitative variation of the major volatile constituents of the linalool producing L. alba chemotype. The volatiles were extracted by solid phase microextraction (SPME) from plants cultivated in soil (mother plants), from in vitro plantlets grown in Murashige & Skoog (MS) medium and from in vitro plantlets grown in MS medium with growth regulators. The content of α-pinene, (Z)-3-hexenyl acetate and α-gurjunene was greater in the mother plants than in plantlets, whereas the content of sabinene, myrcene, 1,8-cineole and p-mentha-1,5,8-triene was lower. The addition of 0.23 µM of IAA to the medium significantly enhanced sabinene and myrcene contents. The addition of 0.92 µM of kinetin significantly increased the 3(S)-(+)-linalool level. [ABSTRACT FROM AUTHOR]

Naturally occurring antioxidants such as carotenoids are extensively studied for their potential in reducing the risk for cancer and other chronic diseases. In the present study, the radical-scavenger activity of the food additive norbixin, a water-soluble carotenoid extracted from Bixa orellana seeds and commercialized as annatto, was evaluated under conditions of DNA damage induced by reactive oxygen species, particularly by hydroxyl radicals. The cell-free scavenger activity of norbixin was evaluated using plasmid DNA as target molecule and Sn2+ or Fe2+ as oxidant. The addition of H2O2 enhanced DNA breakage induced by metal ions, particularly Fe2+. Under these conditions, norbixin started to protect plasmid DNA against single- and double-strand breakage at a metal:norbixin ratio of 1:1 (Sn2+) and 1:10 (Fe2+). However, at lower ratios to Sn2+, norbixin enhanced Sn2+-induced DNA breakage (P<0.05). The ability of norbixin to protect genomic DNA against oxidative damage was assessed in murine fibroblasts submitted to H2O2-induced oxidative stress and the results were evaluated by the comet assay. Under low serum conditions (2 % fetal bovine serum (FBS)), a protective effect of norbixin against H2O2-induced DNA breakage was inversely related to its concentration, a protection ranging from 41 % (10 ??M) TO 21 % (50 ??m). At higher concentrations of norbixin, however, oxidative DNA breakage was still enhanced, even in the presence of a high serum concentration (10 % FBS). Under normal conditions, norbixin per se has no detectable genotoxic or cytotoxic effects on murine fibroblasts. The antimutagenic potential of norbixin against oxidative mutagens was also evaluated by the Salmonella typhimurium assay, with a maximum inhibition of 87 % against the mutagenicity induced by H2O2. Although plasmid DNA and Ames data indicated that norbixin can protect DNA against oxidative damage, it seems to be a risky guardian of genomic DNA as it can also increase the extent of oxidative damage. [ABSTRACT FROM PUBLISHER]

Fresh leaves of Alpinia zerumbet and A. purpurata (Zingiberaceae) were collected in Rio de Janeiro city and subjected to hydrodistillation; their chemical composition was analyzed by GC/MS. These species are used as ornamental plants and in folk medicine. Variations in the leaf oils content and composition of A. zerumbet were found between April and August 2005. In April, the main constituents identified in leaf oil of A. zerumbet were terpinen-7-al (40.5%) and sabinene hydrate (15.4%); in August, the major components identified were terpinen-4-ol (29.4%) and 1,8-cineole (23.1%). Leaf oil of A. purpurata was rich in β-pinene (34.7%) and α-pinene (11.8%). [ABSTRACT FROM AUTHOR]

Ethnopharmacological Relevance: Leaves from Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) are popularly used for healing wounds. Its antileishmanial properties are established in experimental animals, and its active flavonoid components have been identified., Aim of the Study: In this study, we attempted to standardize the extract from K. pinnata leaves by evaluating the influence of season of harvest, sunlight exposure and method of extraction on antileishmanial flavonoids content., Materials and Methods: HPLC-DAD-MS was used to identify and quantify the active antileishmanial flavonoids in different extracts. ANOVA test for analyses of variance followed by the Tukey test of multiple comparisons were used in the statistical analysis. The antileishmanial potential was assessed by the activation of nitric oxide production by murine macrophage using the Griess method., Results: We demonstrated that active flavonoids were significantly more abundant when the leaves were collected in the summer, and that aqueous extraction at 50°C allowed the highest flavonoid extraction. The benefit of sunlight exposure was confirmed in plants cultivated under direct sunlight when compared with those that grown under shade. Under sunny conditions the yield of the most active antileishmanial favonoid quercitrin was increased by 7-fold. All aqueous extracts tested were capable to enhance the macrophage nitric oxide production. However, hot aqueous extract from leaves collected in summer exhibited the higher activity, in agreement with HPLC-DAD-MS analysis tendency. In addition, with the aim of reducing the individual chemical variations of the plant constituents and optimizing the production of the active extract, it was obtained in vitro monoclonal KP specimens that were easily adapted to field conditions and were able to produce antileishmanial flavonoids., Conclusion: Our study reports the better conditions of cultivation, harvest and extraction protocol for obtaining a K. pinnata extract exhibiting the highest antileishmanial activity. Additionally, we propose the flavonoids quercetin 3-O-α-L-arabinopyranosyl (1→2)-α-L-rhamnopyranoside and quercitrin, as satisfactory chemical markers for standardization purposes., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)