Synthesis and structure of azole-fused indeno[2,1-c]quinolines and their anti-mycobacterial properties †

Prompted by our discovery of a new class of conformationally-locked indeno[2,1-c]quinolines as anti-mycobacterials, compounds 2a and 3a

Oxidative DNA Damage Preventive Activity and Antioxidant Potential of Stevia rebaudiana (Bertoni) Bertoni, a Natural Sweetener

At 0.1 mg/mL, the ethyl acetate extract (EAE) of the crude 85% methanolic extract (CAE) of Stevia rebaudiana leaves exhibited preventive activity against DNA strand scission by •OH generated in Fenton’s reaction on pBluescript II SK (–) DNA. Its efficacy is better than that of quercetin. The radical scavenging capacity of CAE was evaluated by the DPPH test (IC50 ) 47.66 ( 1.04 µg/mL). EAE was derived from CAE scavenged DPPH (IC50 ) 9.26 ( 0.04 µg/mL), ABTS+ (IC50 ) 3.04 ( 0.22 µg/mL) and •OH (IC50 ) 3.08 ( 0.19 µg/mL). Additionally, inhibition of lipid peroxidation induced with 25 mM FeSO4 on rat liver homogenate as a lipid source was noted with CAE (IC50 ) 2.1 ( 1.07 mg/mL). The total polyphenols and total flavonoids of EAE were 0.86 mg gallic acid equivalents/mg and 0.83 mg of quercetin equivalents/mg, respectively. Flavonoids, isolated from EAE, were characterized as quercetin-3-O-arabinoside, quercitrin, apigenin, apigenin-4-O-glucoside, luteolin, and kaempferol-3-O-rhamnoside by LC-MS and NMR analysis. These results indicate that Stevia rebaudiana may be useful as a potential source of natural antioxidants