Research, Innovation and Engagements Portfolio, Mangosuthu University of Technology, Durban, 4031, South Africa.
University of South Africa, College of Agriculture and Environmental Sciences Laboratories, Private Bag X06, Florida, Johannesburg, 0710, South Africa.
BMC Complement Altern Med. 2018 Nov 29;18(1):315. doi: 10.1186/s12906-018-2378-3.
Compounds having both anticancer and antimicrobial activity have promising therapeutic potential due to their selective cytotoxicity and their potential to reduce the occurrence of bacterial and fungal infections in immune-compromised cancer patients. In our quest to find new antimicrobial agents with potent anticancer activity, the biological potential of leaves from the three medicinal plants Centella asiatica, Warburgia salutaris and Curtisia dentata as used by Zulu traditional healers for the treatment of cancer is investigated.
Extracts were assayed for antibacterial activity using the agar well diffusion and micro plate dilution assay. In addition, minimum bactericidal concentrations (MBC), lactate dehydrogenase (LDH) release assay and rhodamine 6G intake assay were used to ascertain the antibacterial activity. The cytotoxic effects of the plant extracts were determined using tetrazolium-based colorimetric (MTT) cell proliferation assay against MCF-7, human colorectal carcinoma cells (Caco-2), A549 and HeLa cancerous cell lines.
The acetone extracts from Waburgia salutaris revealed noteworthy anti-proliferative effect yielding IC value of 34.15 μg/ml against MCF-7 cell line, while acetone extract from Curtisia dentata significantly (P ≤ 0.05) revealed promising IC values of 41.55, 45.13, 57.35 and 43.24 μg/ml against A549, HeLa, CaCo-2 and MCF-7 cell lines. The extracts further revealed a broad-spectrum antibacterial activity against bacterial strains used in the study. An acetone extract from W. salutaris revealed the highest zone of inhibition and the lowest minimum inhibitory concentration (MIC) of 21.0 mm and 0.16 mg/ml respectively against Staphylococcus aureus. Methanol extract from W. salutaris and ethyl acetate extract from C. dentata revealed 53% inhibition of R6G inside the cell against Staphylococcus aureus and Escherichia coli respectively in a cytosolic lactate dehydrogenase assay, suggesting that the mode of action of such extracts may be through efflux pump.
Overall, the extracts had good antibacterial activity and anti-proliferative effects against selected cancerous cell lines. Given the good antibacterial activity of the extracts the plants may act as an immune booster and prevent infection in immunosuppressed cancer patients. This is further supported by the plants' anti-proliferative potential, bacteriostatic, bactericidal properties and also their ability to block bacterial efflux pump systems.
具有抗癌和抗菌活性的化合物具有有前景的治疗潜力，因为它们具有选择性细胞毒性，并且有可能减少免疫功能低下的癌症患者中细菌和真菌感染的发生。在寻找具有强大抗癌活性的新型抗菌剂的过程中，我们研究了祖鲁传统治疗师用于治疗癌症的三种药用植物——积雪草、白花油麻藤和弯瓣姜黄的叶子的生物潜力。
使用琼脂孔扩散和微量稀释板测定法检测提取物的抗菌活性。此外，还使用最低杀菌浓度（MBC）、乳酸脱氢酶（LDH）释放测定法和罗丹明 6G 摄取测定法来确定抗菌活性。使用基于噻唑蓝的比色（MTT）细胞增殖测定法，测定植物提取物对 MCF-7、人结直肠癌细胞（Caco-2）、A549 和 HeLa 癌细胞系的细胞毒性作用。
白花油麻藤的丙酮提取物显示出显著的抗增殖作用，对 MCF-7 细胞系的 IC 值为 34.15μg/ml，而弯瓣姜黄的丙酮提取物对 A549、HeLa、Caco-2 和 MCF-7 细胞系的 IC 值分别为 41.55、45.13、57.35 和 43.24μg/ml，具有显著的（P≤0.05）的潜力。提取物还显示出对研究中使用的细菌菌株的广谱抗菌活性。白花油麻藤的丙酮提取物显示出最高的抑制区和最低的最小抑菌浓度（MIC），分别为 21.0mm 和 0.16mg/ml，对金黄色葡萄球菌有抑制作用。白花油麻藤的甲醇提取物和弯瓣姜黄的乙酸乙酯提取物在细胞质乳酸脱氢酶测定中对金黄色葡萄球菌和大肠杆菌的 R6G 分别显示出 53%的抑制作用，这表明此类提取物的作用模式可能是通过外排泵。
总的来说，提取物对选定的癌细胞系具有良好的抗菌活性和抗增殖作用。鉴于提取物的良好抗菌活性，这些植物可能作为免疫增强剂，防止免疫功能低下的癌症患者感染。这进一步得到了植物的抗增殖潜力、抑菌、杀菌特性以及它们阻断细菌外排泵系统的能力的支持。
