Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Scottsville, South Africa.
J Ethnopharmacol. 2012 Feb 15;139(3):728-38. doi: 10.1016/j.jep.2011.11.044. Epub 2011 Dec 6.
Four species of Podocarpus are used in traditional medicine both in human and animal healthcare in South Africa. In vitro pharmacological screening of leaf and stem extracts of these species exhibited potent antimicrobial, anti-inflammatory, anti-tyrosinase, anthelmintic, acetylcholinesterase inhibitory and antioxidant activities.
To investigate the mutagenicity, antimutagenicity and cytotoxicity effects of leaf and stem extract of South African Podocarpus species.
The mutagenicity and cytotoxic effects of extracts from four species of Podocarpus were tested using the Salmonella/microsome assay with and without metabolic activation, based on the plate-incorporation method and neutral red uptake (NRU) assay respectively. Five Salmonella typhimurium tester strains; TA98, TA100, TA102, TA1535 and TA1537 were used for mutagenicity testing. The relative cytotoxicity of the extracts was assessed by determining their NI(50) values (50% inhibition of NRU).
The extracts did not show any mutagenic effects against all the tester strains with or without metabolic activation. All extracts demonstrated a strong antimutagenic effect on the mutations induced by 4NQO, decreasing its mutagenic effect in a dose-dependent manner. Strong cytotoxic effects were exhibited by petroleum ether extracts as compared to 80% ethanol extracts. When HepG2 cells were in contact with plant extracts in an increasing concentration, slopes of NRU decreased (highest-lowest %) following a concentration-dependent pattern. For 80% ethanol extracts, the most toxic extract in terms of percentage viability was leaves of Podocarpus falcatus whereby at 0.2 mg/ml, the viability of the cells was 38.9%. Stem extract of Podocarpus latifolius was the most toxic among PE extracts, giving a percentage viability of 46.4 at 0.1 mg/ml.
Absence of mutagenicity does not indicate lack of toxicity, as was observed from these extracts. These findings will help in assessing the safety measures to be considered in the use of these species and also the need to determine the cytotoxic potential of these species against various forms of human cancer cells.
在南非，有四种罗汉松被用于人类和动物的医疗保健传统医学中。这些物种的叶和茎提取物的体外药理筛选显示出强大的抗菌、抗炎、抗酪氨酸酶、驱虫、乙酰胆碱酯酶抑制和抗氧化活性。
研究南非罗汉松属植物叶和茎提取物的致突变性、抗突变性和细胞毒性作用。
采用平板掺入法和中性红摄取（NRU）试验，分别用沙门氏菌/微粒体试验（有和无代谢活化）检测四种罗汉松提取物的致突变性和细胞毒性作用。使用 5 种鼠伤寒沙门氏菌测试菌株 TA98、TA100、TA102、TA1535 和 TA1537 进行致突变性测试。通过确定其 NI(50) 值（NRU 抑制的 50%）来评估提取物的相对细胞毒性。
提取物在有或没有代谢活化的情况下，对所有测试菌株均未显示出任何致突变作用。所有提取物对 4NQO 诱导的突变均表现出强烈的抗突变作用，以剂量依赖性方式降低其致突变作用。与 80%乙醇提取物相比，石油醚提取物表现出强烈的细胞毒性作用。当 HepG2 细胞与植物提取物接触时，随着浓度的增加，NRU 的斜率呈浓度依赖性下降（最高-最低%）。对于 80%乙醇提取物，以细胞活力百分比计，最具毒性的提取物是罗汉松 falcatus 的叶，在 0.2mg/ml 时，细胞活力为 38.9%。在 PE 提取物中，Podocarpus latifolius 的茎提取物毒性最大，在 0.1mg/ml 时，细胞活力为 46.4%。
缺乏致突变性并不表示缺乏毒性，从这些提取物中可以观察到这一点。这些发现将有助于评估在使用这些物种时需要考虑的安全措施，以及确定这些物种对各种人类癌细胞的细胞毒性潜力的必要性。
