Idowu T O, Ogundaini A O, Adesanya S A, Onawunmi G O, Osungunna M O, Obuotor E M, Abegaz B M
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
Department of Pharmacognosy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
Afr J Tradit Complement Altern Med. 2016 Aug 12;13(5):182-189. doi: 10.21010/ajtcam.v13i5.24. eCollection 2016.
The plant, is indigenous to Nigeria and its stem-bark has wide application in traditional medicine for the treatment of infections and oxidative stress related diseases. The aim of the study was to isolate the chemical constituents responsible for the antioxidant and antibacterial activity from the stem-bark of the plant in order to justify some of its ethnomedicinal uses.
Crude extract of stem-bark of obtained from 80% ethanol was successively partitioned with ethyl acetate (EtOAc) and -butanol. The solvent fractions and isolated compounds were tested for antioxidant property using 2-2-diphenyl-1-picrylhydrazyl. Antibacterial activities were also assessed by means of agar-diffusion and broth micro dilution methods. EtOAc fraction was repeatedly fractionated on column chromatography to afford four compounds and their chemical structures were established using NMR (1D and 2D) and MS.
Chromatographic fractionation of EtOAc fraction with the highest antioxidant and antimicrobial activities afforded stigmasterol (),: epicatechin (),: epigallocatechin (): and procyanidin B5 ().: Procyanidin B5 isolated for the first time from genus demonstrated the highest antioxidant activity with IC50 values of 8.8 μM and 11.20 μM in DPPH and nitric oxide assays respectively and equally demonstrated the highest inhibitory activity against (MIC 156.25 μg/mL), (MIC 156.25 μg/mL), (MIC 625 μg/mL) and (MIC 156.25 μg/mL).
The antibacterial and antioxidant activities of epicatechin, epigallocatechin and procyanidin B5 isolated from stem-bark validate the folkloric uses.
该植物原产于尼日利亚，其茎皮在传统医学中广泛应用于治疗感染和氧化应激相关疾病。本研究的目的是从该植物的茎皮中分离出具有抗氧化和抗菌活性的化学成分，以证明其一些民族药用用途的合理性。
从80%乙醇中获得的该植物茎皮粗提物依次用乙酸乙酯（EtOAc）和正丁醇进行分配。使用2,2-二苯基-1-苦基肼对溶剂馏分和分离出的化合物进行抗氧化性能测试。还通过琼脂扩散法和肉汤微量稀释法评估抗菌活性。对EtOAc馏分进行柱色谱反复分离，得到四种化合物，并使用核磁共振（一维和二维）和质谱确定其化学结构。
具有最高抗氧化和抗菌活性的EtOAc馏分经色谱分离得到豆甾醇（）、表儿茶素（）、表没食子儿茶素（）和原花青素B5（）。首次从该属植物中分离出的原花青素B5在DPPH和一氧化氮测定中表现出最高的抗氧化活性，IC50值分别为8.8 μM和11.20 μM，并且对金黄色葡萄球菌（MIC 156.25 μg/mL）、大肠杆菌（MIC 156.25 μg/mL）、铜绿假单胞菌（MIC 625 μg/mL）和白色念珠菌（MIC 156.25 μg/mL）同样表现出最高的抑制活性。
从该植物茎皮中分离出的表儿茶素、表没食子儿茶素和原花青素B5的抗菌和抗氧化活性证实了其民间药用价值。
