An Ethnobotanical Survey of Poisonous Medicinal Plants in the Shouf Biosphere Reserve, Lebanon

Abstract

Local communities of the Shouf Biosphere Reserve (SBR) have a long history of traditional use of medicinal plants. However, such use has sometimes been accompanied by toxicity symptoms. Therefore, this study aimed to document the ethnobotanical knowledge about the toxicity of medicinal plant species used by local people. Ethnobotanical information was collected during 2019-2021 using semi- structured questionnaires and personal interviews involving 133 local informants (68 women and 65 men with an average age of 58 years). The Frequency of Citation (FC) index was calculated from the data collected during the interviews, which allowed the generation of a list of poisonous plant species used to treat different diseases. The toxicity of highly cited species was discussed according to phytochemical profiles reported in the literature. The findings resulted in a list of 31 plant species from 22 botanical families, with Asteraceae, Euphorbiaceae, and Solanaceae being the most dominant. The most toxic plant species were Ecballium elaterium (L.) A.Rich (FC 11%), Sambucus ebulus L., Ricinus communis L., and Arum palaestinum Boiss. (each of FC 10%). Herbs were the most dominant life form of the cited species. The most toxic parts were the leaves (22% of citations), followed by whole plants and seeds (each 17%), and fruits (11%). Oral ingestion and skin contact were the main routes of toxicity. According to the published literature, toxicity can be primarily attributed to biochemical compounds, such as cucurbitacins, proteaceous glycoprotein, ricin, tropane alkaloids, atropine, cyanogenic glycosides, and pyrrolizidine alkaloids, among other compounds. This work highlights the importance of the traditional knowledge of poisonous plants used in folk medicine and the need for phytochemical and toxicological research. The development of regulatory measures on the use and trade of medicinal plants as well as raising awareness of practitioners and public are also deemed necessary.