Herbal medicines have been used with therapeutical purposes for thousands of years. Its popular use has been transmitted across generations and is described in the pharmacopeas. Since the development of organic chemistry, it became possible to obtain pure substances by isolating active substances from plants, among them, digoxine and morphine, resulting in lack of interest for research of substances originated from vegetals. However, from the 1980's onwards, new methods for isolating active substances were developed and it became possible to identify substances in complex samples such as vegetal extracts, restoring the interest for vegetally-originated compounds that could be used as prototypes for the development of new drugs. Nowadays, in spite of the growing importance of herbal medicines, relatively few studies have been performed to prove efficacy and safety, while many plants are still used on the basis of popular well-established use. The objective of this paper is to assess the availability of pre-clinical toxicity data for ten medicinal plants marketed as herbal medicines in Brazil, in major databases and public sources of information. Few data were found regarding pre-clinical toxicity on the ten medicinal plants surveyed, but, in general, experiments in animals showed low acute, sub-acute and chronical toxicity and did not show mutagenic or teratogenic toxicity.
Toxicological information; Herbal medicines; Medicinal plants; Pre-clinical toxicity
