Phytochemical investigation, antioxidant and antibacterial activities of the fruit extracts of <i>Solanum anguivi</i>

<i>Solanum anguivi</i> Lam. is an ethnomedicinal plant. Local traditional practitioners believe that it reduces the risk of diabetes and atherosclerosis diseases. The present study was intended to conduct qualitative phytochemical analysis, determine the total flavonoid and phenolic contents, estimate the antioxidant capacity and antibacterial activities of the extracts of the fruits of this plant. The antioxidant activity was determined by analyzing the radical scavenging activity (RSA) using 2,2-diphenyl-1-picryhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activities were determined by the agar well diffusion method. Qualitative phytochemical screening of the crude extracts obtained from the fruits of the plant indicated the presence of alkaloids, flavonoids, phenols, glycosides, steroids, terpenoids, saponins and tannins. The highest total phenolic and total flavonoid content were obtained in the ethanol extract of the fruits, followed by dichloromethane and <i>n</i>-hexane extract. The total phenolic content (in gallic acid equivalents, GAE) ranged from 113.3 to 202.72 mg GAE/g. The total flavonoid content (in catechin equivalent, CE) varied from 61.72 to 142.64 mg (CE)/g. All fruit extracts of <i>S. anguivi</i> exhibited antioxidant activity as revealed by DPPH and FRAP assays. The DPPH RSA (% inhibition) of the fruit extract varied from 35.11 to 80.13. The total phenolic and Flavonoid contents showed alinear correlation with RSA. Furthermore, all fruit extracts showed antibacterial activity against gram-positive and gram-negative bacteria varying from 12.5 to 16.75 mm. The result showed that the extracts of the plant exerted stronger bactericidal effect on gram-positive bacteria than on gram-negative bacteria. Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1993087 .<i>Solanum anguivi</i> Lam. 是一种民族药用植物。当地传统医药从业者认为其可降低糖尿病与动脉粥样硬化的发病风险。本研究旨在对该植物果实提取物开展定性植物化学分析，测定总黄酮与总酚类物质含量，评估其抗氧化能力与抗菌活性。抗氧化活性通过2,2-二苯基-1-苦肼基（2,2-diphenyl-1-picryhydrazyl, DPPH）自由基清除活性（RSA）试验与铁还原抗氧化能力（ferric reducing antioxidant power, FRAP）试验进行测定。抗菌活性则采用琼脂打孔扩散法测定。对该植物果实粗提物的定性植物化学筛选结果显示，其含有生物碱、黄酮类、酚类、糖苷类、甾体类、萜类、皂苷类与鞣质类成分。该植物果实的乙醇提取物总酚类与总黄酮含量最高，其次为二氯甲烷提取物与正己烷提取物。总酚类物质含量以没食子酸当量（gallic acid equivalents, GAE）计，范围为113.3~202.72 mg GAE/g；总黄酮含量以儿茶素当量（catechin equivalent, CE）计，范围为61.72~142.64 mg CE/g。DPPH与FRAP试验结果显示，<i>S. anguivi</i> 的所有果实提取物均表现出抗氧化活性。果实提取物的DPPH自由基清除抑制率介于35.11%~80.13%之间。总酚类与总黄酮含量与自由基清除活性呈线性相关。此外，所有果实提取物对革兰氏阳性菌与革兰氏阴性菌均表现出抗菌活性，抑菌圈直径介于12.5~16.75 mm之间。研究结果表明，该植物提取物对革兰氏阳性菌的杀菌效果强于革兰氏阴性菌。本文补充数据可在线获取，链接为https://doi.org/10.1080/13102818.2021.1993087。