Department of Plant and Soil Sciences, University of Pretoria, Pretoria, 0002, South Africa.
Department of Pharmacology, University of the Free State, Bloemfontein, 9301, South Africa.
J Ethnopharmacol. 2020 Oct 28;261:113101. doi: 10.1016/j.jep.2020.113101. Epub 2020 Jun 17.
Approximately 70% of anticancer drugs were developed or derived from natural products or plants. Southern Africa boasts an enormous floral diversity with approximately 22,755 plant species with an estimated 3000 used as traditional medicines. In South Africa more than 27 million individuals rely on traditional medicine for healthcare. The use of South African plants for the treatment of cancer is poorly documented, however there is potential to develop anticancer agents from these plants. Limited ethnobotanical studies report the use of plants for cancer treatment in traditional medicine. Plants growing in tropical or subtropical regions, such as in South Africa, produce important secondary metabolites as a protective mechanism, which could be used to target various factors that play a key role in carcinogenesis.
The aim was to collate information from primary ethnobotanical studies on South African plants traditionally used for the treatment of cancer. Evaluation of literature focused on traditionally used plants that have been tested for their in vitro activity against cancer cells. Secondary metabolites, previously identified within these plant species, were also included for discussion regarding their activity against cancer. The toxicity was evaluated to ascertain the therapeutic potential in further studies. Additionally, the aim was to highlight where a lack of reports were found regarding plant species with potential activity and to substantiate the need for further testing.
A review of ethnobotanical surveys conducted in South Africa for plants used in the treatment of cancer was performed. Databases such as Science Direct, PubMed and Google Scholar, university repositories of master's dissertations and PhD theses, patents and books were used. Plant species showing significant to moderate activity were discussed regarding their toxicity. Compounds identified within these species were discussed for their activity against cancer cells and toxicity. Traditionally used plants which have not been scientifically validated for their activity against cancer were excluded.
Twenty plants were documented in ethnobotanical surveys as cancer treatments. Numerous scientific reports on the potential in vitro activity against cancer of these plants and the identification of secondary metabolites were found. Many of the secondary metabolites have not been tested for their activity against cancer cells or mode of action and should be considered for future studies. Lead candidates, such as the sutherlandiosides, sutherlandins, hypoxoside and pittoviridoside, were identified and should be further assessed. Toxicity studies should be included when testing plant extracts and/or secondary metabolites for their potential against cancer cells to give an indication of whether further analysis should be conducted.
There is a need to document plants used traditionally in South Africa for the treatment of cancer and to assess their safety and efficacy. Traditionally used plants have shown promising activity highlighting the importance of ethnobotanical studies and traditional knowledge. There are many opportunities to further assess these plants and secondary metabolites for their activity against cancer and their toxic effects. Pharmacokinetic studies are also not well documented within these plant extracts and should be included in studies when a lead candidate is identified.
大约 70%的抗癌药物是从天然产物或植物中开发或衍生而来的。南部非洲拥有丰富的花卉多样性，约有 22755 种植物，估计有 3000 种被用作传统药物。在南非，超过 2700 万人依赖传统医学进行医疗保健。南非植物在癌症治疗中的应用记录很少，然而，从这些植物中开发抗癌药物是有潜力的。有限的民族植物学研究报告了在传统医学中使用植物治疗癌症。在南非等热带或亚热带地区生长的植物，作为一种保护机制，会产生重要的次生代谢物，这些代谢物可用于针对在癌变过程中起关键作用的各种因素。
本研究旨在整理南非传统上用于治疗癌症的植物的主要民族植物学研究信息。评估文献侧重于已针对其体外抗癌细胞活性进行测试的传统使用植物。还包括这些植物物种中以前鉴定的次生代谢物，讨论其对癌症的活性。评估毒性以确定进一步研究的治疗潜力。此外，还旨在强调在具有潜在活性的植物物种方面缺乏报告的地方，并证实需要进一步测试。
对南非用于治疗癌症的植物进行了民族植物学调查的综述。使用了 Science Direct、PubMed 和 Google Scholar 等数据库、大学硕士论文和博士论文库、专利和书籍。对显示出显著或中度活性的植物物种进行了讨论，以了解其毒性。对这些物种中鉴定出的化合物进行了讨论，以了解它们对癌细胞的活性和毒性。没有科学验证对癌症有活性的传统使用植物被排除在外。
在民族植物学调查中，有 20 种植物被记录为癌症治疗方法。发现了大量关于这些植物潜在体外抗癌活性的科学报告以及次生代谢物的鉴定。许多次生代谢物尚未测试其对癌细胞的活性或作用模式，应考虑用于未来的研究。已确定了先导候选物，如 sutherlandiosides、sutherlandins、hypoxoside 和 pittoviridoside，应进一步评估。在测试植物提取物和/或次生代谢物对癌细胞的潜在活性时，应包括毒性研究，以表明是否应进行进一步分析。
有必要记录南非传统上用于治疗癌症的植物，并评估其安全性和疗效。传统上使用的植物表现出有希望的活性，突出了民族植物学研究和传统知识的重要性。有许多机会可以进一步评估这些植物和次生代谢物的抗癌活性及其毒性作用。这些植物提取物的药代动力学研究也没有很好地记录下来，在确定先导候选物时应将其纳入研究。
