Flavonoids of Helichrysum chasmolycicum and its antioxidant and antimicrobial activities

From the aerial parts of Helichrysum chasmolycicum P.H Davis, which is an endemic species in Turkey, the flavonoids apigenin, luteolin, kaempferol, 3,5-dihydroxy-6,7,8-trimethoxyflavone, 3,5-dihydroxy-6,7,8,4′-tetramethoxyflavone, apigenin 7-O-glucoside, apigenin 4′-O-glucoside, luteolin 4′-O-glucoside, luteolin 4′,7-O-diglucoside, kaempferol 3-O-glucoside, kaempferol 7-O-glucoside and quercetin 3-O-glucoside were isolated. The methanol extract of the aerial parts of H. chasmolycicum showed antioxidant activity by DPPH method (IC50 0.92mg/mL). Antimicrobial activity test was performed on the B, D, E extracts and also 3,5-dihydroxy-6,7,8-trimethoxyflavone and kaempferol 3-O-glucoside which were the major flavonoid compounds obtained from aerial parts of H. chasmolycicum by microbroth dilutions technique. The E (ethanol-ethyl acetate) extract showed moderate antimicrobial activity against Pseudomonas aeruginosa, B (petroleum ether-60% ethanol-chloroform) extract and 3,5-dihydroxy-6,7,8-trimethoxyflavone showed moderate antifungal activity against Candida albicans. © 2010 Elsevier B.V

Vasorelaxant and blood pressure lowering effects of alchemilla vulgaris: A comparative study of methanol and aqueous extracts

Background: In the last decade, a growing interest particularly in determining the cardiovascular effects of herbal extracts took place among researchers. Objective: Herein, we aimed to investigate the microvascular and blood pressure lowering effects of two differently processed extracts of the same herb, Alchemilla vulgaris (Rosaceaea), which was revealed to contain high levels of vasoactive compounds. Materials and Methods: For the purpose, endothelium intact rat mesenteric arteries were mounted in a myograph system and contracted with prostaglandin F 2α (PGF 2α: 3 × 10−5 M) or potassium chloride (K + : 40 mM). Then, aqueous and methanol extracts were added at 0.01-10 mg/ml concentrations in a cumulative manner. Results: Both extracts produced relaxations in PGF 2α (3 × 10−5 M) precontracted arteries which were insensitive to the inhibitors of endothelium derived vasoactive substances namely, L G -nitro-L-arginine (10−4 M), ODQ (10−5 M) and indomethacin (10−5 M) or removal of endothelium. Opposite vascular effects were observed when extracts were applied in K + precontracted arteries. In addition, oral administration of the methanol extract of Alchemilla vulgaris, but not the aqueous extract, reduced blood pressure significantly in L-NAME hypertensive rats. Conclusion: Our results demonstrated that the methanol extract of Alchemilla vulgaris has more prominent and favourable vascular effects in normal and experimental hypertensive conditions reinforcing its traditional use in cardiovascular disorders, in particular hypertension. These results most likely give rise to further studies to reveal its mechanism of action and clinical value of this herb

Endothelium-dependent vasorelaxant effect of Alchemilla vulgaris methanol extract: a comparison with the aqueous extract in rat aorta

We aimed to investigate the vascular effects of methanol extract (ME) and aqueous extract (AE) of Alchemilla vulgaris (Rosaceaea). Increasing concentrations of the ME (0.01-10 mg/mL) produced relaxations in noradrenaline (NA: 10(-6) M) and K+ (40mM) precontracted aortas while contractions were obtained with the AE (0.01-10 mg/mL). Responses to the ME were inhibited in the presence of putative inhibitors of endothelial vasodilators or after removal of the endothelium. Pretreatment of aortic rings with the ME (10 mg/mL, 20 min) reduced the maximal contractions to NA and K+, whereas an enhanced contractility was observed with the AE (10 mg/mL, 20 min). Total flavonoid content was higher in the ME than in the AE. Quercetin was determined particularly high in the ME while gallic acid was high in the AE. Our results indicated that the ME of A. vulgaris displays favourable vascular effects via endothelium-dependent mechanisms