three major flavonoid fractions were separated from a methanol extract of calendula officinalis flowers by preparative tlc. these fractions were evaluated for the inhibition of parent and tamoxifen resistant t47d human breast cancer cells. we also examined the effect of quercetin and isorhamnetin on the growth of parent and resistant t47d cells in the presence and absence of tamoxifen. it was f...

      Tribulus terrestris L. var. orientalis (Kerner) G. Beck is widely used in the traditional medicine of many countries. Several flavonoides are identified from the plant material. Aerial parts which collected from northeast of Iran are used in this study. Three flavonoid glycosides were isolated and characterized. The flovonoids were found to be based on quercetin...

To systematically study the effects of the number of d electrons of the first transition metal ions (Fe, Co, Ni, Cu and Zn) on the formation and stability of metal flavonoid complexes, we took the quercetin/M2+ complex as a model system to investigate the structures and properties of these complexes. Based on considerable structural information obtained through ESI-MSn, all of the first transit...

Nine flavonoid compounds: kaempferol 3-0-beta-(6"-p-coumaroyl)-glucopyranoside, myricetin 3-O-beta-glucopyranoside, quercetin 3-0-beta-glucopyranoside, quercetin 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, kaempferol 3-0-beta-glucopyranoside, kaempferol 3-0-alpha-rhamnopyranosyl (1-->6)-beta-glucopyranoside, quercetin 7-0-beta-glucoside, quercetin 7-0-beta-diglucoside, kaempferol 7-...

Many studies have demonstrated that the flavonoid quercetin protects against cardiovascular disease (CVD) and related risk factors. Atherosclerosis, the underlying cause of CVD, is also attenuated by oral quercetin administration in animal models. Although macrophages are key players during fatty streak formation and plaque progression and aggravation, little is known about the effects of querc...

plants are rich source of phenolic compounds (phenolic acids, flavonoids and tannins) that are most important natural antioxidants. in the present study two ultrasonic methods including probe and bath were used for the extraction of phenolic and flavonoid compounds from celtis australis. the effects of different extraction time including 30, 60 and 90 min (bath method) and 5, 10 and 20 min (pro...

Quercetin, a flavonoid present in many plants, is reported to be effective in models of neurodegenerative diseases. The aim of the present study was to evaluate the anti-tremor effects of quercetin in 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. In rats, quercetin had no effect on apomorphine-induced rotations, but it could significantly attenuate muscle tremor of 6-OHDA...

Whilst mitotic rat embryonic cardiomyoblast-derived H9c2 cells have been widely used as a model system to study the protective mechanisms associated with flavonoids, they are not fully differentiated cardiac cells. Hence, the aim of this study was to investigate the cardioprotective and cardiotoxic actions of quercetin and two of its major in vivo metabolites, quercetin 3-glucuronide and 3'-O-m...

The effect of the flavonoid quercetin on epithelial chloride secretion has been studied in vitro. These studies were performed using monolayers of the human colonic epithelial cell line T84, mounted in modified Ussing chambers. Chloride secretion was assessed as changes in short circuit current (I(SC)) both in basal conditions as well as in response to different secretagogues: carbachol (100 mi...

Citrullus colocynthis (Linn.) Schrad. is an important medicinal plant belonging to family Cucurbitaceae. Flavonoid "quercetin" was isolated from in vivo (leaf, stem, fruit and root) and in vitro callus of the species. The dried samples were separately soxhlet extracted in 80% methanol and then reextracted with petroleum ether, diethyl ether and ethyl acetate. The fraction was concentrated and s...