Chemistry Department, Jomo Kenyatta University of Agriculture and Technology, P.O Box 62000-00200, Nairobi, Kenya.
Pharmaceutical Chemistry Department, Mount Kenya University, P.O. Box 342-01000, Thika, Kenya.
BMC Complement Med Ther. 2024 Apr 2;24(1):137. doi: 10.1186/s12906-024-04449-7.
A study carried out by World Health Organization revealed that around 80% of individuals globally depends on herbal forms of medication with 40% of pharmaceutical products being sourced from medicinal plants. The study objective was to evaluate the phytochemicals composition, in vitro antimicrobial and antioxidant properties of the leaves of Terminalia catappa L. aqueous and methanolic extracts.
Antimicrobial activity was analyzed by disk diffusion, the minimum inhibitory concentration in-vitro assays with ciprofloxacin as the standard for antibacterial assay while nystatin for antifungal assay. Ferric reducing antioxidant power and 2,2-diphenyl-1-picryl-hydrazyl-hydrate assays were used for the evaluation of antioxidant properties of the crude extracts while the groups responsible for this activity identified using Fourier transform infrared spectrophotometer.
The study found that the leaves of Terminalia catappa contained alkaloids, tannins, steroids, cardiac glycosides, flavonoids, phenols, saponins, and coumarins, but terpenoids were absent. Presence of functional groups associated with this class of compounds such as OH vibrational frequencies were observed in IR spectrum of the crude extracts. Methanolic extract from Terminalia catappa exhibited greater antibacterial properties against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus, whereas aqueous extract displayed greater antibacterial activity against Bacillus subtilis for all concentrations tested. The amount of the sample that scavenged 50 percent of DPPH (IC50) was found to be 8.723, 13.42 and 13.04 µg/mL for L-ascorbic acid, Terminalia catappa L. methanolic and aqueous extracts respectively. The antimicrobial and antioxidant activities varied with the extract concentration and solvent used in extractions.
Terminalia catappa L. leaves are prospective for use as a source of therapeutic agents that could lead to the advancement of new antimicrobial and antioxidant products.
世界卫生组织进行的一项研究表明，全球约有 80%的人依赖草药形式的药物，其中 40%的药物来自药用植物。该研究的目的是评估诃子叶的水提物和醇提物的植物化学成分、体外抗菌和抗氧化特性。
采用圆盘扩散法分析抗菌活性，用环丙沙星作为抗菌测定的标准，制霉菌素作为抗真菌测定的标准，进行体外最小抑菌浓度测定。采用铁还原抗氧化能力和 2,2-二苯基-1-苦肼基-肼水合物测定法评估粗提取物的抗氧化特性，并用傅里叶变换红外光谱仪确定负责该活性的基团。
研究发现，诃子叶含有生物碱、单宁、类固醇、强心苷、类黄酮、酚类、皂苷和香豆素，但不含萜类化合物。在粗提取物的红外光谱中观察到与这类化合物相关的功能基团，如 OH 振动频率。诃子叶的甲醇提取物对铜绿假单胞菌、大肠杆菌和金黄色葡萄球菌表现出较强的抗菌活性，而水提物在所有测试浓度下对枯草芽孢杆菌表现出较强的抗菌活性。清除 DPPH（IC50）的 50%所需的样品量分别为 L-抗坏血酸、诃子叶甲醇提取物和水提取物的 8.723、13.42 和 13.04μg/mL。抗菌和抗氧化活性随提取物浓度和提取溶剂的变化而变化。
诃子叶有望作为治疗剂的来源，可能导致新的抗菌和抗氧化产品的发展。
