Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Fort Hare, Alice, South Africa.
Int J Antimicrob Agents. 2011 Oct;38(4):319-24. doi: 10.1016/j.ijantimicag.2011.05.002. Epub 2011 Jul 14.
The aim of this study was to isolate and identify phytochemicals with anti-Helicobacter pylori activity from the stem bark of Sclerocarya birrea. The plant crude extract was fractionated by silica gel column and thin layer chromatography techniques, initially with ethyl acetate (EA) and subsequently with a combination of ethyl acetate/methanol/water (EMW). Further fractionation and identification of the phytoconstituents was achieved by gas chromatography and mass spectrometry (GC/MS) analysis. The antimicrobial activity of the fractions and compounds was evaluated against five metronidazole- and clarithromycin-resistant strains of H. pylori as well as a reference strain ATCC 43526 using the microbroth dilution technique. Amoxicillin was included in the experiments as a positive control antibiotic. Of the 18 fractions collected, 16 demonstrated anti-H. pylori activity with 50% minimum inhibitory concentration (MIC(50)) values ranging from 310 μg/mL to 2500 μg/mL. Two of the fractions (EMW fraction 6 and EA fraction 1) revealed the presence of 5 and 24 compounds, respectively, representing 40.5% and 86.57% of the total composition. Most of the compounds were essential oils, with terpinen-4-ol being the most abundant agent (35.83%), followed by pyrrolidine (32.15%), aromadendrene (13.63%) and α-gurjunene (8.77%). MIC(50) ranges for amoxicillin, terpinen-4-ol and pyrrolidine were 0.0003-0.06 μg/mL, 0.004-0.06 μg/mL and 0.005-6.3 μg/mL, respectively. The inhibitory activities of terpinen-4-ol and pyrrolidine were similar to amoxicillin (P>0.05). Most of these compounds are being reported in this plant for the first time and may represent new sources of therapeutically useful compounds against H. pylori.
本研究旨在从甜叶悬钩子茎皮中分离和鉴定具有抗幽门螺杆菌活性的植物化学物质。植物粗提取物通过硅胶柱和薄层色谱技术进行分离，首先用乙酸乙酯（EA），然后用乙酸乙酯/甲醇/水（EMW）混合物。通过气相色谱和质谱（GC/MS）分析进一步分离和鉴定植物成分。使用微量稀释技术评估各馏分和化合物对 5 株甲硝唑和克拉霉素耐药的幽门螺杆菌菌株以及参考菌株 ATCC 43526 的抗菌活性。阿莫西林被包括在实验中作为阳性对照抗生素。在所收集的 18 个馏分中，有 16 个显示出抗幽门螺杆菌活性，其 50%最小抑菌浓度（MIC(50)）值范围为 310μg/ml 至 2500μg/ml。两个馏分（EMW 馏分 6 和 EA 馏分 1）分别显示存在 5 和 24 种化合物，分别占总成分的 40.5%和 86.57%。大多数化合物为精油，其中萜品-4-醇含量最丰富（35.83%），其次是吡咯烷（32.15%）、芳樟醇（13.63%）和α-古巴烯（8.77%）。阿莫西林、萜品-4-醇和吡咯烷的 MIC(50)范围分别为 0.0003-0.06μg/ml、0.004-0.06μg/ml 和 0.005-6.3μg/ml。萜品-4-醇和吡咯烷的抑制活性与阿莫西林相似（P>0.05）。这些化合物中的大多数在该植物中首次被报道，可能代表治疗幽门螺杆菌的新的有价值的化合物来源。
