Chemical composition and biological properties of Ipomoea procumbens

ABSTRACT Natural products have been the most valuable source of chemical compounds in the discovery of novel medicines. Secondary metabolites from terrestrial and marine organisms have found considerable use in the treatment of numerous diseases and have been considered lead molecules both in their natural form and as templates for medicinal chemistry. Brazil has an exceptionally rich biodiversity, and a valuable source of secondary metabolites that can be useful for the development of bioproducts. Ipomoea species, Convolvulaceae, are mostly found in tropical and sub-tropical regions, including South America and many are used for nutritional and medicinal purposes. Ipomoea procumbens Mart. & Choisy is endemic from South America, and this is the first study reported on the chemical composition and biological activities of this species. The present work reports the tentatively identification of natural products present in the extracts using a high performance liquid chromatography-high resolution mass spectrometry method. Additionally, the antioxidant and antifungal biological activities of the leaves, roots and steams extracts and fractions of this species were evaluated. While for the antioxidant activity the hydromethanol fractions (leaves, stem and roots) were more active, the methanol fractions of leaves and stem provided better results for the antifungal assay.

Free radical reactions of a naturally occurring flavone baicalein and possible mechanisms towards its membrane protective properties.

Baicalein (5, 6, 7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavone present in some of the medicinal plants is known for its potential therapeutic effects, such as cardioprotective, anticancer and anti-inflammatory properties. However, detailed role and mechanisms behind its protective properties against different generators for oxidative stress have not been examined. In the present study, we investigated the possible protective ability of baicalein against the membrane damage caused by reactive oxygen species (ROS) and reactive nitrogen species (RNS) and the mechanisms involved using pulse radiolysis technique. Baicalein offered efficient protection even at a concentration of 10 M towards membrane damage caused by lipid peroxidation induced by the -radiation, peroxyl radicals, ascorbate-Fe2+ and peroxynitrite in rat liver mitochondria and heart homogenate. To elucidate its reaction mechanisms with biologically relevant radicals, transient absorption spectroscopy employing pulse radiolysis technique was used. Baicalein showed fairly high rate constants (3.7 × 109, 1.3 × 109 and 8.0 × 108 dm3 mol-1 s-1 for hydroxyl, azidyl and alkylchloroperoxyl radicals, respectively), suggesting that baicalein can act as an effective scavenger of these radicals. In each case, the phenoxyl radical of baicalein was generated. Thus, it was evident that the phenolic moiety of baicalein was responsible for the free radical scavenging process. Baicalein also reacts with linoleic acid peroxyl radical (LOO·), indicating its ability to act as a chain breaking antioxidant. Peroxynitrite-mediated radicals were shown to be reactive towards baicalein and the bimolecular rate constants were 2.5 × 107 and 3 × 108 dm3 mol-1 s-1 for ·NO2 and CO3·- radicals, respectively. In conclusion, our results revealed the potential of baicalein in protecting mitochondrial membrane against oxidative damage induced by the four different agents. We propose that the protective effect is mediated via scavenging of primary and secondary radicals generated during oxidative stress.

Lipid Peroxide Levels and Total Peroxyl Radical-Trapping Ability in the Placenta of Women with Normal Pregnancy and Preeclampsia / 대한산부인과학회잡지

OBJECTIVE: Our purpose was to investigate lipid peroxide levels, total peroxyl radical-trapping antioxidative parameter (TRAP) values, and antioxidant vitamin levels in placental tissues of women with preeclampsia and to evaluate their roles in the pathophysiology of preeclampsia. STUDY DESIGN: Samples of placental tissue homogenates were obtained from 23 normal and 18 preeclamptic women between 33 and 40 weeks gestation. TNF-alpha was assayed by an enzyme-linked immunoassay. Lipid peroxide levels measured by thiobarbituric acid reaction. The TRAP values were measured by modified Wayners method. Ascorbic acid, uric acid, retinol, alpha-tocopherol, and gamma-tocopherol were measured by high performance liquid chromatography (HPLC) CoulArray detector. RESULTS: TNF-alpha levels in placental tissue homogenates of women with preeclampsia were significantly higher than that of women with preeclampsia (21.4+/-3.39 vs. 10.3+/-1.06 pg/ml, p<0.05). Lipid peroxide levels in placental tissue homogenates of women with preeclampsia were significantly higher than that of women with preeclampsia (6.65+/-0.57 vs. 4.98+/-0.37 nmol/mg protein, p<0.05). TRAP values in placental tissue homogenates of women with preeclampsia were significantly lower than that of women with normal pregnancy (0.24+/-0.02 vs. 0.31+/-0.03 mM, p<0.05). Ascorbic acid levels in placental tissue homogenates of women with preeclampsia were significantly lower than that of women with normal pregnancy (217.0+/-21.0 vs. 333.3+/-32.8 nmol/ml, p<0.05). CONCLUSION: The above results suggest that increased oxidative stress in placenta is involved in the pathophysiology of preeclampsia and ascorbic acid may act as an important preventive factor in the development of preeclampsia.