Manteiga R, Park D L, Ali S S
Department of Nutritional Sciences, University of Arizona, Tucson 85721, USA.
Rev Environ Contam Toxicol. 1997;150:1-30. doi: 10.1007/978-1-4612-2278-1_1.
Plants have been used for medicinal purposes for centuries. Health-oriented individuals are turning to herbal teas as alternatives to caffeinated beverages such as coffee, tea, and cocoa and for low-caloric supplements. The popularity of herbal tea consumption has increased significantly during the past two decades in the U.S. Hundreds of different teas made up of varied mixtures of roots, leaves, seeds, barks, or other parts of shrubs, vines, or trees are sold in health food stores. Although chemists have been characterizing toxic plant constituents for over 100 years, toxicological studies of herbal teas have been limited and, therefore, the safety of many of these products is unknown. Plants synthesize secondary metabolites that are not essential in the production of energy and whose role may be in the defense mechanisms as plant toxins to their interactions with other plants, herbivores, and parasites. Pyrrolizidine alkaloids (PAs) were among the first naturally occurring carcinogens identified in plant products, and their presence in herbal teas is a matter of public health significance. Some herbal tea mixtures and single-ingredient herbal teas have been analyzed for toxic/mutagenic potential by bioassay and chromatographic techniques. Numerous human and animal intoxications have been associated with naturally occurring components, including pyrrolizidine alkaloids, tannins, and safrole. Thus, the prevention of human exposure to carcinogens or mutagens present in herbal tea mixture extracts is crucial. Preparation of infusion drinks prepared from plants appears to concentrate biologically active compounds and is a major source of PA poisoning. The quantity and consumption over a long period of time is of major concern. It is recommended that widespread consumption of herbal infusions should be minimized until data on the levels and varieties of carcinogens, mutagens, and toxicants are made available.
几个世纪以来，植物一直被用于药用。注重健康的人开始饮用花草茶，以替代咖啡、茶和可可等含咖啡因的饮料，并作为低热量的补充饮品。在过去二十年里，花草茶在美国的消费量显著增加。健康食品商店出售由数百种不同的茶组成的饮品，这些茶由根、叶、种子、树皮或灌木、藤蔓或树木的其他部分混合而成。尽管化学家们对有毒植物成分进行了100多年的研究，但对花草茶的毒理学研究仍然有限，因此，许多这类产品的安全性尚不清楚。植物合成次生代谢产物，这些产物在能量生产中并非必不可少，其作用可能是作为植物毒素参与植物与其他植物、食草动物和寄生虫相互作用的防御机制。吡咯里西啶生物碱（PAs）是在植物产品中发现的首批天然致癌物之一，它们在花草茶中的存在具有公共卫生意义。一些花草茶混合物和单一成分的花草茶已通过生物测定和色谱技术分析其毒性/诱变潜力。许多人和动物中毒事件都与天然成分有关，包括吡咯里西啶生物碱、单宁和黄樟素。因此，预防人体接触花草茶混合物提取物中存在的致癌物或诱变剂至关重要。用植物制备冲泡饮料似乎会浓缩生物活性化合物，这是PA中毒的主要来源。长时间的摄入量和消费情况是主要关注点。建议在获得有关致癌物、诱变剂和毒物的含量及种类的数据之前，尽量减少花草茶的广泛消费。
