A comparative study on biological activities of different solvent extracts from whole seed, seed coat and cotyledon of two Lathyrus species

Abstract The present study was conducted to assess the phenolic content, and antibacterial and antioxidant activities of Lathyrus L. species. The extraction of phenolic compounds from whole seeds, seed coat and cotyledon of Lathyrus hierosolymitanus Boiss. and Lathyrus annuus L. seeds was performed employing different solvents. Total phenolic content (TPC) was measured by Folin- Ciocalteau assay, while the antioxidant activity was determined by DPPH radical scavenging activity, and reducing power assay. It was found that TPC of extracts ranged from 0.12 mg to 6.53 mg GAE/gdw. For each solvent, seed coat extracts were generally observed to render higher TPC and antioxidant activities. There was a correlation between TPC and antioxidant activity. In addition, all extracts were also examined for their antimicrobial activity against Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Methanol extracts showed the highest antibacterial activity which is consistent with TPC, but there was no correlation between TPC and antibacterial activity. Solvents were observed to have effects on gallic acid, caffeic acid, and epicatechin extractions. HPLC analysis results of extracts confirmed methanol and ethanol as preferred solvents for phenolic extraction from Lathyrus sp. Phenolic content in the extracts could be suggested to contribute to their antioxidant and antibacterial activity.

摘要 本研究旨在评估山黧豆属（Lathyrus L.）物种的酚类含量、抗菌与抗氧化活性。本研究采用不同溶剂，对耶路撒冷山黧豆（Lathyrus hierosolymitanus Boiss.）和一年生山黧豆（Lathyrus annuus L.）的全种子、种皮及子叶中的酚类化合物进行提取。采用福林-酚法（Folin-Ciocalteau assay）测定总酚含量（Total phenolic content，简称TPC），通过DPPH自由基清除活性（DPPH radical scavenging activity）与总还原力测定法评估抗氧化活性。结果显示，提取物的总酚含量范围为0.12 mg至6.53 mg 没食子酸当量每克干重（GAE/gdw）。对于每种溶剂而言，种皮提取物通常表现出更高的总酚含量与抗氧化活性，且总酚含量与抗氧化活性存在相关性。此外，本研究还检测了所有提取物对蜡样芽孢杆菌（Bacillus cereus）、大肠杆菌（Escherichia coli）及铜绿假单胞菌（Pseudomonas aeruginosa）的抗菌活性。甲醇提取物的抗菌活性最高，该结果与总酚含量的变化趋势一致，但总酚含量与抗菌活性之间并无相关性。研究发现，溶剂种类对没食子酸（gallic acid）、咖啡酸（caffeic acid）及表儿茶素（epicatechin）的提取效果存在影响。提取物的高效液相色谱（HPLC）分析结果证实，甲醇与乙醇是从山黧豆属物种中提取酚类化合物的优选溶剂。提取物中的酚类成分或为其抗氧化与抗菌活性的贡献来源。