Influence of a series of natural flavonoids on free radical generating systems and oxidative stress

Abstract

1. A series of flavonoids isolated from Indian medicinal plants: kaempferol-3-O-galactoside, hispidulin, nepetin, scutellarein, scutellarein-7-O-glucuronide, hibifolin and morelloflavone were studied for their activity as inhibitors of microsomal lipid peroxidation and scavengers of oxygen free radicals in vitro as well as in a model of xenobiotic toxicity in mouse. 2. All compounds inhibited lipid peroxidation in vitro. The most potent compounds were nepetin (non-enzymic lipid peroxidation) and morelloflavone (enzymic lipid peroxidation) with IC50's in the micromolar range. Some of the compounds behaved as scavengers of hydroxyl radical in the deoxyribose degradation assay, with a calculated rate constant for kaempferol-3-O-galactoside of 1.55 x 10(10) M-1 s-1. 3. Scutellarein and nepetin were found to be inhibitors of xanthine oxidase activity, whereas morelloflavone acted as a scavenger of superoxide generated by hypoxanthine/xanthine oxidase. 4. Treatment of mice with scutellarein, hispidulin, nepetin and kaempferol-3-O-galactoside after bromobenzene intoxication decreased serum glumate-pyruvate transaminase activity, although only the last flavonoid was able to significantly reduce hepatic lipid peroxidation products and to increase the reduced glutathione level. In contrast, morelloflavone increased bromobenzene toxicity.

Non-toxic melanin production inhibitors from Garcinia livingstonei (Clusiaceae)

“…The activity of morelloflavone (1) as an antiinflammatory (Gil et al, 1997;Castardo et al, 2008) and antioxidant (Sanz et al, 1994;Deachathai et al, 2005;Hutadilok-Towatana et al, 2007) are well-documented; it has also been found to be a potent tyrosinase inhibitor (Masuda et al, 2005), anti-HIV-1 (Lin et al, 1997), and anti-bacterial (Verdi et al, 2004) agent, and to have antimalarial (Ngouamegne et al, 2008) and analgesic (Luzzi et al, 1997) properties. Isojacareubin (5) is known for its activity as an anticoagulant (Wu et al, 1998), and 6-deoxyisojacareubin (6) for its antifungal (Morel et al, 2002) and antibacterial (Kuete et al, 2007) properties, while sargaol (4) shows marked activity as an antioxidant (Nahas et al, 2007).…”

Effect of Aquilegia vulgaris (L.) ethyl ether extract on liver antioxidant defense system in rats

“…The level of lipid peroxidation was asseyed by measuring thiobarbituric acid reactive substances (TBARS) [2]. GSH level was assayed in the liver homogenate prepared in phosphate buffer (pH = 7.4) using the method of Sedlak and Lindsay [16] with Ellman's reagent.…”

“…Synthetic antioxidants have been shown to produce numerous side effects. Hence, the therapeutic use of medicinal plants in reducing free radical-induced tissue injury has been considered [1,2]. Aquilegia vulgaris (L.) (Ranunculaceae), syn.…”

HPLC analysis of flavonoids in Eupatorium littorale

“…In an early study 8 they showed significant cytotoxic action against KB cells. Anti-oxidant 15 and antihepatotoxic 16,17 properties have also been described for these compounds. Hispidulin itself has been found to have antibacterial 18 , antiedema 19 as well as plant germination and root growth inhibition activities 20 .…”