Nguena-Dongue Branly-Natalien, Amobonye Ayodeji, Waleguele Claire Christine, Asong Stella Tofac, Tchuenguia Claire Vianey, Menkem Elisabeth Zeuko'o, Pillai Santhosh
Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa; Antimicrobial Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Studies, Department of Biochemistry, Faculty of Science, University of Yaoundé I, PO Box 812, Cameroon.
Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa; Department of Polymer Chemistry and Technology, Kaunas University of Technology, Radvilenu Rd. 19, 50254, Kaunas, Lithuania.
J Ethnopharmacol. 2025 Jun 20;352:120144. doi: 10.1016/j.jep.2025.120144.
Cananga odorata, Terminalia catappa, and Terminalia mantaly are widely used in traditional medicine in Cameroon to treat several illnesses, like diarrhoea, gastroenteritis, genital candidiasis, and oral candidiasis.
This study aimed to investigate the antimicrobial, antibiofilm activities and phytochemical profiling of extracts from three medicinal plants C. odorata, T. catappa, and T. mantaly from Cameroon.
Crude ethanol, hydro-ethanol, and water extracts of the three selected Cameroonian medicinal plants were prepared and tested against 9 bacteria and 4 yeast strains in vitro. The most active extract was selected for further evaluation, including antibiofilm activities, time-kill kinetics, nucleic acid leakage, salt tolerance on Pseudomonas aeruginosa and Candida albicans, as well as antioxidant and cytotoxicity on Raw and Vero cells. Additionally, morphological cell disruption observations using scanning electron microscopy and GC-MS analysis were conducted.
Out of 36 extracts tested, 23 showed activities against bacteria and 12 against yeasts, with MIC values ranging from 62.5 μg/mL to 1000 μg/mL. The most effective extract was the ethanolic extract of T. mantaly stem bark (TMb EtOH), which demonstrated broad-spectrum antimicrobial activity against P. aeruginosa (MIC 250 μg/mL) and C. albicans (MIC 62.5 μg/mL), through nucleotide leakage and salt tolerance tests. TMb EtOH also exhibited significant antioxidant activity (IC of 17.83 ± 1.25, 17.41 ± 1.24, and 27.66 ± 1.442 μg/mL on DPPH, ABTS, and FRAP, respectively) and low toxicity on Raw and Vero cells (CC of 168.55 ± 3.32 and 439.85 ± 16.47 μg/mL, respectively). Scanning electron micrographs confirmed the ability of TMb EtOH to interact, destabilise, and disrupt microbial cell walls, as evidenced by the multiple deflations, depressions and indentations. Furthermore, GC-MS analysis identified 37 compounds in the extract, with betulin (13.11 %) being the most predominant compound, well-known for its antimicrobial and antioxidant properties.
This study highlights the potential of the ethanolic extract of T. mantaly stem bark as a promising source of antimicrobial compounds. The bio-guided fractionation of TMb EtOH is ongoing to isolate and purify these compounds for drug discovery purposes.
依兰香、榄仁树和非洲榄仁在喀麦隆的传统医学中被广泛用于治疗多种疾病，如腹泻、肠胃炎、生殖器念珠菌病和口腔念珠菌病。
本研究旨在调查喀麦隆三种药用植物依兰香、榄仁树和非洲榄仁提取物的抗菌、抗生物膜活性及植物化学特征分析。
制备了三种选定的喀麦隆药用植物的粗乙醇提取物、水乙醇提取物和水提取物，并在体外对9种细菌和4种酵母菌株进行了测试。选择活性最强的提取物进行进一步评估，包括抗生物膜活性、时间杀菌动力学、核酸泄漏、对铜绿假单胞菌和白色念珠菌的耐盐性，以及对Raw细胞和Vero细胞的抗氧化和细胞毒性。此外，还进行了使用扫描电子显微镜的形态学细胞破坏观察和气相色谱-质谱分析。
在测试的36种提取物中，23种对细菌有活性，12种对酵母有活性，最低抑菌浓度值范围为62.5μg/mL至1000μg/mL。最有效的提取物是非洲榄仁茎皮乙醇提取物（TMb EtOH），通过核苷酸泄漏和耐盐性测试，它对铜绿假单胞菌（最低抑菌浓度250μg/mL）和白色念珠菌（最低抑菌浓度62.5μg/mL）表现出广谱抗菌活性。TMb EtOH还表现出显著的抗氧化活性（在DPPH、ABTS和FRAP上的半数抑制浓度分别为17.83±1.25、17.41±1.24和27.66±1.442μg/mL），并且对Raw细胞和Vero细胞毒性较低（半数细胞毒性浓度分别为168.55±3.32和439.85±16.47μg/mL）。扫描电子显微镜照片证实了TMb EtOH与微生物细胞壁相互作用、使其不稳定并破坏的能力，多个瘪陷、凹陷和压痕证明了这一点。此外，气相色谱-质谱分析在提取物中鉴定出37种化合物，其中桦木醇（13.11%）是最主要的化合物，以其抗菌和抗氧化特性而闻名。
本研究突出了非洲榄仁茎皮乙醇提取物作为抗菌化合物潜在来源的可能性。正在对TMb EtOH进行生物导向分级分离，以分离和纯化这些化合物用于药物研发目的。
