Ghanta Srijani, Banerjee Anindita, Poddar Avijit, Chattopadhyay Sharmila
Drug Development/Diagnositcs and Biotechnology Division, Indian Institute of Chemical Biology, Kolkata, India.
J Agric Food Chem. 2007 Dec 26;55(26):10962-7. doi: 10.1021/jf071892q. Epub 2007 Nov 27.
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 microg/mL). EAE was derived from CAE scavenged DPPH (IC50=9.26+/-0.04 microg/mL), ABTS+ (IC50=3.04+/-0.22 microg/mL) and *OH (IC50=3.08+/-0.19 microg/mL). Additionally, inhibition of lipid peroxidation induced with 25 mM FeSO 4 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.
在0.1 mg/mL浓度下，甜叶菊叶85%甲醇粗提物（CAE）的乙酸乙酯提取物（EAE）对Fenton反应中产生的OH导致的pBluescript II SK (-) DNA链断裂具有预防活性。其效果优于槲皮素。通过DPPH试验评估CAE的自由基清除能力（IC50 = 47.66±1.04 μg/mL）。源自CAE的EAE清除DPPH（IC50 = 9.26±0.04 μg/mL）、ABTS+（IC50 = 3.04±0.22 μg/mL）和OH（IC50 = 3.08±0.19 μg/mL）。此外，CAE对以大鼠肝脏匀浆为脂质源、由25 mM硫酸亚铁诱导的脂质过氧化有抑制作用（IC50 = 2.1±1.07 mg/mL）。EAE的总多酚和总黄酮分别为0.86 mg没食子酸当量/mg和0.83 mg槲皮素当量/mg。通过LC-MS和NMR分析，从EAE中分离出的黄酮类化合物被鉴定为槲皮素-3-O-阿拉伯糖苷、槲皮苷、芹菜素、芹菜素-4-O-葡萄糖苷、木犀草素和山柰酚-3-O-鼠李糖苷。这些结果表明甜叶菊可能是一种潜在的天然抗氧化剂来源。
