Department of Pharmacology, Faculty of Health Sciences, University of Pretoria, South Africa.
J Ethnopharmacol. 2012 Mar 27;140(2):398-404. doi: 10.1016/j.jep.2012.01.036. Epub 2012 Jan 31.
Bacterial infections remain a significant threat to human health. Due to the emergence of widespread antibiotic resistance, development of novel antibiotics is required in order to ensure that effective treatment remains available. There are several reports on the ethnomedical use of Tabernaemontana elegans pertaining to antibacterial activity.
The aim of this study was to isolate and identify the fraction responsible for the antimicrobial activity in Tabernaemontana elegans (Stapf.) root extracts.
The active fraction was characterized by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). Antibacterial activity was determined using the broth micro-dilution assay and antimycobacterial activity using the BACTEC radiometric assay. Cytotoxicity of the crude extract and fractions was assessed against primary cell cultures; lymphocytes and fibroblasts; as well as a hepatocarcinoma (HepG2) and macrophage (THP-1) cell line using the Neutral Red uptake and MTT assays.
The crude root extracts were found to contain a high concentration of alkaloids (1.2%, w/w). GC-MS analysis identified the indole alkaloids, voacangine and dregamine, as major components. Antibacterial activity was limited to the Gram-positive bacteria and Mycobacterium species, with MIC values in the range of 64-256μg/ml. When combined with antibiotics, additive antibacterial effects were observed. Marked cytotoxicity to all cell lines tested was evident in the MTT and Neutral Red uptake assays, with IC(50) values <9.81μg/ml.
This study confirms the antibacterial activity of Tabernaemontana elegans and supports its potential for being investigated further for the development of a novel antibacterial compound.
细菌感染仍然是对人类健康的重大威胁。由于广泛存在抗生素耐药性，需要开发新型抗生素以确保仍然有有效的治疗方法。有几份关于 Tabernaemontana elegans（Stapf.）根提取物具有抗菌活性的民族医学用途的报告。
本研究的目的是分离和鉴定 Tabernaemontana elegans（Stapf.）根提取物中具有抗菌活性的成分。
通过薄层层析（TLC）和气相色谱-质谱联用（GC-MS）对活性部位进行了表征。采用肉汤微量稀释法测定抗菌活性，采用 BACTEC 放射测量法测定抗分枝杆菌活性。采用中性红摄取和 MTT 测定法评估粗提取物及其馏分对原代细胞培养物（淋巴细胞和成纤维细胞）以及肝癌（HepG2）和巨噬细胞（THP-1）细胞系的细胞毒性。
发现粗根提取物含有高浓度的生物碱（1.2%，w/w）。GC-MS 分析鉴定出吲哚生物碱，即 voacangine 和 dregamine，为主要成分。抗菌活性仅限于革兰氏阳性菌和分枝杆菌属，MIC 值在 64-256μg/ml 范围内。与抗生素联合使用时，观察到具有相加的抗菌作用。MTT 和中性红摄取测定均显示出对所有测试细胞系的明显细胞毒性，IC50 值<9.81μg/ml。
本研究证实了 Tabernaemontana elegans 的抗菌活性，并支持进一步研究其作为新型抗菌化合物的潜力。
