Allergy-preventive activity was demonstrated for the MeOH extract (HM) of the petals of Hibiscus mutabilis L. 'versicolor' MAKINO in a continuing search for allergy-preventive substances from natural sources, using the in vivo assay method. This assay system uses monitoring of a decrease in the blood flow at the tail vein of mice subjected to hen egg-white lysozyme (HEL) sensitization. By bioas...

quercetin, a ubiquitous flavonol, represents a promising leading drug for development of new chemotherapeutic agents. however, its limited cytotoxicity to cancer cells hampers its clinical use. in order to obtain novel quercetin derivatives with superior cytotoxicity, seven alkylated quercetin derivatives were synthesized. solubility of these derivatives was determined by turbidimetry. cytotoxi...

Salsola is one of the largest and most important genera in the family Chenopodiaceae. Salsola species are used for their anti-inflammatory, antinociceptive, anthelmintic and antipruritic effects and also as diuretic in traditional medicines worldwide. The aim of the present study is to assess the activity potential of the extracts, subextracts and isolated compounds from the aerial parts of and...

Purification of a MeOH extract from the aerial parts of Hylomecon vernalis Maxim. (Papaveraceae) using column chromatography furnished a new acetylated flavonol glycoside (1), together with twenty known phenolic compounds (2-21). Structural elucidation of 1 was based on 1D- and 2D-NMR spectroscopy data analysis to be quercetin 3-O-[4‴-O-acetyl-α-L-arabinopyranosyl]-(1‴→6″)-β-D-galactopyranoside...

Seven flavonoids were isolated from the butanol fraction of the methanolic extract of the aerial parts of Cynanchum acutum L. (Asclepiadaceae). All of which have been isolated for the first time from the genus Cynanchum. Their structures were established as quercetin 3-O-beta-galacturonopyranoside (1), quercetin 7-O-beta-glucopyranoside (2), tamarixtin 3-O-beta-galacturonopyranoside (3), kaempf...

The flavonoid quercetin reduces blood pressure and endothelial dysfunction in animal models of hypertension. However, the results concerning the relationship between quercetin and NO present a complex picture. We have analyzed the mechanisms involved in the NO scavenging effects of quercetin and its repercussion on NO bioactivity in vascular smooth muscle. Quercetin scavenged NO with apparent z...

Lychee pulp contains phenolic compounds that are strong antioxidants, but the identities of the major antioxidants present are unknown. In the present study, the major contributors to the antioxidant activity of fresh lychee pulp were identified and their cellular antioxidant activities were investigated. Aqueous acetone extracts of lychee pulp were fractionated on polyamide resin, and those fr...

A chemical behavior of Quercetin as antioxidant and metal chelator has become the subject of intense experimental research. In this paper, we apply a semi empirical approach to study the stability constant of Quercetin with metals like Cd, Pb and Bi. The comparative analysis of the theoretical formation constant of Quercetin-metal complexes with metals with experimental results shows that H-rem...

In the course of search for potent inhibitors of chitin synthase II from natural resources, seven tannins and related compounds were isolated from the aerial part of Euphorbia pekinensis and identified as gallic acid (1), methyl gallate (2), 3-O-galloyl-(-)-shikimic acid (3), corilagin (4), geraniin (5), quercetin-3-O-(2"-O-galloyl)-beta-D-glucoside (6), and kaempferol-3-O-(2"-O-galloyl)-beta-D...

Water lily, the member of the Nymphaeaceae family, is the symbol of Buddhism and Brahmanism in India. Despite its limited researches on flower color variations and formation mechanism, water lily has background of blue flowers and displays an exceptionally wide diversity of flower colors from purple, red, blue to yellow, in nature. In this study, 34 flavonoids were identified among 35 tropical ...