Assessment of the Diversity of Medico-Magic Knowledge on Four Herbaceous Species in Benin

BACKGROUND: Ethnobotanical knowledge on four herbaceous species, Acmella uliginosa (Sw.) Cass., Momordica charantia L., Phyllanthus amarus Schumach. & Thonn., and Scoparia dulcis L., in Benin was investigated. METHODS: Herbal medicine traders in six different markets were interviewed using a semi-structured questionnaire. The linear regression test was performed to check for the influence of respondent's age on ethnobotanical uses they hold. Relative frequency citation, fidelity level, use value, and Rahman similarity index were calculated to assess the diversity of medico-magic knowledge. The Informant Consensus Factor is not applicable in this study since we are dealing neither with the diversity of medicinal plants used by a community of people nor with a great number of plant species used for medicinal purposes, nor the diversity of plant species used in the treatment of a specific or group of ailments. RESULTS: The respondent's age did not influence the ethnobotanical uses they hold on the species. All thirty-six informants surveyed traded Phyllanthus amarus Schumach. & Thonn., Momordica charantia L., and Scoparia dulcis L., and the majority traded Acmella uliginosa (Sw.) Cass. The respondent's age does not influence the diversity of ethnobotanical uses they hold on the study species. Purchase in traders' own markets was the predominant source of Phyllanthus amarus Schumach. & Thonn., Momordica charantia L., and Scoparia dulcis L. while Acmella uliginosa (Sw.) Cass. was mostly purchased in other more distant markets. A noticeable proportion of traders also collect Phyllanthus amarus Schumach. & Thonn. and Momordica charantia L. from wild populations. Phyllanthus amarus Schumach. & Thonn. was the species most demanded by customers followed by Momordica charantia L. Traders confirmed the scarcity of all species in recent years and climate change and destruction of natural habitats for logging were the most cited causes. The entire plant of Phyllanthus amarus Schumach. & Thonn. was used mainly to treat malaria, diabetes, and constipation, and decoction with oral administration was the most frequent preparation for malaria treatment. To treat diabetes, informants mixed Phyllanthus amarus Schumach. & Thonn. with Momordica charantia L. used as a decoction with oral administration. Momordica charantia L. was also used to treat measles and chicken pox. Acmella uliginosa (Sw.) Cass. and Scoparia dulcis L. were mostly used for their spiritual use for luck, predominantly by chewing fresh leaves or flowers, and by bathing with the ground plant mixed with soap, respectively. Overall, Momordica charantia L. had the greatest use value followed by Phyllanthus amarus Schumach. & Thonn. The majority of traders do not plant the species. CONCLUSIONS: The harvesting and trade of the species threaten their natural populations and urgent tools, including in situ and ex situ conservation, are needed to ensure their long-term sustainable exploitation.