Yanda Lambert, Tatsimo Simplice J N, Tamokou Jean-De-Dieu, Matsuete-Takongmo Germaine, Meffo-Dongmo Sylvie Carolle, Meli Lannang Alain, Sewald Norbert
Department of Chemistry, Faculty of Sciences, The University of Maroua, Maroua, Cameroon.
Natural Product and Environmental Chemistry Group (NAPEC), Department of Chemistry, Higher Teachers' Training College, University of Maroua, Box 55, Maroua, Cameroon.
Int J Anal Chem. 2022 Feb 17;2022:4205823. doi: 10.1155/2022/4205823. eCollection 2022.
(G. &Perr.) Taub (Mimosaceae) is a large tree native to dry tropical Africa and characteristic of dry leguminous forests. Different parts of this plant are used to treat wounds, skin infection, and to fight against cancer. Literature review indicated various pharmacological properties. Despite these medicinal properties, the chemical composition studies remain limited. This study aims to isolate and characterize secondary metabolites from leaves and evaluate their antibacterial and antioxidant properties. Air-dried powdered leaves of were macerated in methanol at room temperature and partitioned with ethyl acetate. The EtOAc extract was subjected successively to flash and column chromatographies in order to isolate compounds. The structure of the isolates was determined with help of spectroscopic data including 1D and 2D NMR experiments and comparison with literature data. The antibacterial activities were evaluated via determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antioxidant activities were evaluated via gallic acid equivalent antioxidant capacity (GEAC) and diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. The chemical investigation of the EtOAc extract led to the isolation of seven compounds: (2, 6) farnesylamine (1), myricetin-3-O-rhamnoside (2), bis(2-ethylhexyl) benzene-1,2-dicarboxylate (3), lupeol (4), -sitosterol (5), stigmasterol glycoside (6), and a mixture of bis(2-ethylhexyl) benzene-1,2-dicarboxylate (3) and bis(2-ethylhexyl) benzene-1,4-dicarboxylate (7) in ratio 1 : 2. Compound 1 is described here for the first time as a natural product with complete H and C assignments. Compounds 3 and 7 were identified as artefacts from dichloromethane. Sesquiterpene amine (1) is reported in genus for the first time. Antibacterial and antioxidant activities of isolated compounds were investigated. Among the tested samples, the EtOAc extract and compound 2 exhibited the highest antioxidant (EC = 5.67-77.56 g/mL; GEAC = 36.58-89.28 g/mL) and antibacterial (MIC = 8-64 g/mL) activities against gram-negative and gram-positive bacteria. The EtOAc extract and compound 2 from exhibited antibacterial activity through bacteriolytic effects and reduction of the antioxidant defenses in the bacterial cells. Furthermore, the chemotaxonomic significance of isolated compounds was discussed. The antibacterial and antioxidant activities of ethyl acetate extract and compound 2 can justify the traditional uses of leaves for the treatment of diseases related to bacterial infections. The presence of compounds 1, 2, and 4 in this plant should also be considered as valuable chemotaxonomic features.
（G. & Perr.）陶布（含羞草科）是一种原产于干燥热带非洲的大树，是干燥豆科森林的特征树种。这种植物的不同部位用于治疗伤口、皮肤感染和对抗癌症。文献综述表明其具有多种药理特性。尽管有这些药用特性，但化学成分研究仍然有限。本研究旨在从树叶中分离和鉴定次生代谢产物，并评估它们的抗菌和抗氧化特性。将风干的树叶粉末在室温下用甲醇浸渍，并用乙酸乙酯进行分配。乙酸乙酯提取物先后进行快速柱色谱和柱色谱以分离化合物。借助包括一维和二维核磁共振实验在内的光谱数据并与文献数据进行比较来确定分离物的结构。通过测定最低抑菌浓度（MIC）和最低杀菌浓度（MBC）来评估抗菌活性。通过没食子酸当量抗氧化能力（GEAC）和二苯基-1-苦基肼（DPPH）自由基清除试验来评估抗氧化活性。对乙酸乙酯提取物的化学研究导致分离出七种化合物：（2, 6）法呢基胺（1）、杨梅素-3-O-鼠李糖苷（2）、双（2-乙基己基）苯-1,2-二羧酸酯（3）、羽扇豆醇（4）、β-谷甾醇（5）、豆甾醇糖苷（6）以及双（2-乙基己基）苯-1,2-二羧酸酯（3）和双（2-乙基己基）苯-1,4-二羧酸酯（7）的比例为1∶2的混合物。化合物1在此首次被描述为具有完整氢和碳归属的天然产物。化合物3和7被鉴定为来自二氯甲烷的人工产物。倍半萜烯胺（1）首次在该属中被报道。对分离出的化合物的抗菌和抗氧化活性进行了研究。在测试的样品中，乙酸乙酯提取物和化合物2对革兰氏阴性菌和革兰氏阳性菌表现出最高的抗氧化（EC = 5.67 - 77.56 μg/mL；GEAC = 36.58 - 89.28 μg/mL）和抗菌（MIC = 8 - 64 μg/mL）活性。来自该植物的乙酸乙酯提取物和化合物2通过溶菌作用和降低细菌细胞中的抗氧化防御表现出抗菌活性。此外，还讨论了分离出的化合物在化学分类学上的意义。乙酸乙酯提取物和化合物2的抗菌和抗氧化活性可以证明该植物叶子用于治疗与细菌感染相关疾病的传统用途是合理的。该植物中化合物1, 2和4的存在也应被视为有价值的化学分类学特征。
