New Indices for Ethnotoxicological Assessment of Medicinal Plants: Example of Tafilalet Region, Morocco.

Background: Several botanical species are poisonous and are used for medicinal purposes in traditional medicine. In fact, a relationship between toxicity and phytotherapeutic potential of medicinal plants exists.

Objective: Until now, there is no ethnopharmacological indices evaluating mathematically the toxic property of any medicinal plant used traditionally. Consequently, it is important to find this link through the establishment and development of novel indices that put into consideration the relationship between toxicity and phytotherapy. Two essential objectives were targeted in the present investigation: firstly, we aimed to establish novel indices which permit researchers to evaluate data obtained in any ethnobotanical survey targeting toxic plants. Secondly, we aimed also to collect data and information about toxic species, mainly those used traditionally for therapeutic purposes in the region of Tafilalet (southeast of Morocco).

Methods: The total informant interviewed in our study was 1616 (where 1500 were simple local inhabitants and 116 were herbalists). This inquiry was carried out through semi-structured and structured interviews and the sampling technique used was the stratified sample (9 stratums). Data obtained was analyzed using 3 new indices: Degree of Taxonomic Toxicity (DT), Degree of Botanical Families Toxicity (DFT) and Relative Link of Toxicity (RLT).

Results: 47 toxic species belonging to 38 botanical families were quoted in our survey. The highest value of DT was observed for Atractylis gummifera L. (DT=24.67). According to the calculated value of DFT, the most toxic plant family in the region of Tafilalet was Asteraceae (DFT=143.90). Nervous system disorders are the main ailment caused by the toxicity of poisonous species used in the traditional medicine in Tafilalet (RLT=1.44).

Conclusion: Novel indices established in this investigation (DT, DFT and RLT) have been demonstrated to be useful for interpreting data collected in Tafilalet region and could serve for other ethnopharmacological surveys of toxic medicinal plants.