Mpofu Smart J, Msagati Titus A M, Krause Rui W M
Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, P.O. Box 1701, Johannesburg, 2028, South Africa.
Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
Afr J Tradit Complement Altern Med. 2013 Nov 2;11(1):34-52. eCollection 2014.
Elephantorrhiza elephantina (Ee) and Pentanisia prunelloides (Pp) are two medicinal plants which are widely used to remedy various ailments including diarrhoea, dysentery, inflammation, fever, rheumatism, heartburn, tuberculosis, haemorrhoids, skin diseases, perforated peptic ulcers and sore joints in southern Africa (South Africa, Swaziland, Botswana and Zimbabwe). The following study was conducted to explore the in vitro cytotoxicity, antioxidant properties and phytochemical profile of the two medicinal plants.
The cytotoxicity of the aqueous and methanol extracts and fractions of both species was studied using the brine shrimp lethality tests (BST) for the first time.
The results demonstrated that the lethality (LC50) for crude extracts for both plants ranged between 1.8 and 5.8 ppm and was relatively greater than that for the methanol, ethyl acetate and chloroform fractions of the extracts which ranged between 2.1 ppm and 27 ppm. This suggested that crude extracts were more potent than their respective fractions, further explaining that the different fractions of phytochemicals in these plant species work jointly (in synergy) to exert their therapeutic efficacy. Both aqueous and methanol extracts of the two medicinal plants demonstrated a high degree of antioxidant capacity against the DPPH radical with the Duh and Yen inhibition percentage ranging between 4.5% and 72%. Phytochemical studies of the rhizome extracts showed that the major compounds present include flavonoids, tannins, anthocyanidins, anthraquinones, triterpenoids (oleanolic acid), the steroidal saponin Diosgenin, the sugars, rhamnose, glucuronic acid, Arabinose and hexoses.
This is the first report of the detection and isolation of diosgenin and oleanolic acid from the rhizome extracts of Ee and Pp. All structures were determined using spectroscopic/spectrometric techniques (1H NMR and 13C and LC-ESI-MS) and by comparison with literature data.
象腿豆（Elephantorrhiza elephantina，Ee）和矮桃草（Pentanisia prunelloides，Pp）是两种药用植物，在非洲南部（南非、斯威士兰、博茨瓦纳和津巴布韦）被广泛用于治疗各种疾病，包括腹泻、痢疾、炎症、发烧、风湿、胃灼热、肺结核、痔疮、皮肤病、消化性溃疡穿孔和关节疼痛。开展以下研究以探究这两种药用植物的体外细胞毒性、抗氧化特性和植物化学特征。
首次使用卤虫致死试验（BST）研究了这两种植物的水提取物、甲醇提取物及其馏分的细胞毒性。
结果表明，两种植物粗提取物的致死率（LC50）在1.8至5.8 ppm之间，相对高于提取物的甲醇、乙酸乙酯和氯仿馏分，后者的致死率在2.1 ppm至27 ppm之间。这表明粗提取物比其各自的馏分更有效，进一步说明这些植物物种中不同馏分的植物化学物质共同（协同）发挥其治疗功效。两种药用植物的水提取物和甲醇提取物对DPPH自由基均表现出高度的抗氧化能力，Duh和Yen抑制率在4.5%至72%之间。根茎提取物的植物化学研究表明，主要化合物包括黄酮类化合物、单宁、花青素、蒽醌、三萜类化合物（齐墩果酸）、甾体皂苷薯蓣皂苷元、糖类、鼠李糖、葡萄糖醛酸、阿拉伯糖和己糖。
这是首次从象腿豆和矮桃草根茎提取物中检测和分离出薯蓣皂苷元和齐墩果酸的报告。所有结构均通过光谱/光谱技术（1H NMR、13C和LC-ESI-MS）并与文献数据比较来确定。
