Acrocarpus fraxinifolius Wight and Arn. Bark; phenolics, toxicity studies, antioxidant and anti-inflammatory activities

The purpose of the survey was to determine acute & chronic toxicity; in vivo antioxidant and anti-inflammatory actions of the different extracts of A. fraxinifolius Wight and Arn bark; along with estimation of the phenolic, flavonoidal contents and investigation of phenolic metabolites that may attribute to the activities. LD50 of the total ethanol extract (TEE) was 7.1 g/kg b. wt, the radical scavenging activity of DPPH showed 60.31% inhibition, FRAP ability and ABTS+ activity showed 55.024 and 67.217 µmol Trolox/100 g dry weight, respectively. TEE followed by ethyl acetate extract (EAE) at 100 mg/kg b.w exhibited the highest in vivo antioxidant activity (94.51% and 91.08% potency, respectively) compared with Vit E (100%). The TEE & EAE exhibited the highest anti-inflammatory activity (3.81±0.08 & 3.79±.0.04) respectively in comparison with indomethacin 3.83±0.01 measured as edema diameter after 4 hours of extract administration. The total phenolic and total flavonoid contents in the total ethanol extract (TEE) estimated as gallic acid and catechin equivalents were 61.06± 0.08 μg eq GA/g, 40.33± 0.20 μg CE/g extract respectively. EAE revealed five phenolic acids and eight flavonoid compounds isolated for the first time from the plant.

本研究旨在测定白蜡叶猴耳环（A. fraxinifolius Wight and Arn）树皮不同提取物的急、慢性毒性，以及其体内抗氧化与抗炎活性；同时定量分析提取物中的总酚、总黄酮含量，并探究可能与其活性相关的酚类代谢物。总乙醇提取物（TEE）的半数致死量（LD50）为7.1 g/kg体重。DPPH自由基清除活性的抑制率达60.31%；铁还原抗氧化能力（FRAP）与ABTS+自由基清除活性分别为55.024 μmol Trolox/100 g干重、67.217 μmol Trolox/100 g干重。在100 mg/kg体重剂量下，总乙醇提取物（TEE）与乙酸乙酯提取物（EAE）的体内抗氧化活性最高，分别为维生素E（Vit E，100%活性参照）的94.51%与91.08%。总乙醇提取物与乙酸乙酯提取物的抗炎活性亦最为显著，给药4小时后以水肿直径为评价指标，其测定值分别为3.81±0.08与3.79±0.04，而阳性对照吲哚美辛的对应测定值为3.83±0.01。总乙醇提取物（TEE）中的总酚与总黄酮含量以没食子酸（GA）当量与儿茶素（CE）当量计，分别为61.06±0.08 μg 没食子酸当量/克提取物、40.33±0.20 μg 儿茶素当量/克提取物。乙酸乙酯提取物（EAE）中首次从该植物中分离得到5种酚酸与8种黄酮类化合物。