Toxicological Characterization of Ten Medicinal Plants of the Beninese Flora Used in the Traditional Treatment of Diarrheal Diseases

Abstract

The use of medicinal plants in traditional medicine is a common practice in developing countries. However, this unregulated or poorly rational use may present a dose-dependent risk of toxicity to humans. This study aimed to explore the phytochemical and toxicological characteristics of ten (10) plant species used in the traditional treatment of infectious diarrhea in Benin. The acute toxicity of aqueous and hydroethanolic extracts of Khaya senegalensis, Daniellia oliveri, Rauvolfia vomitoria, Vernonia amygdalina, Manihot esculenta, Ocimum gratissimum, Senna italica, Diospyros mespiliformis, Pterocarpus erinaceus, and Anacardium occidentale was evaluated following the OECD 423 protocol at a single dose of 2000 mg/kg. This safety test was complemented by a larval cytotoxicity test. Hematological and biochemical examinations, as well as a histological study of the liver and kidneys, were performed. Larval cytotoxicity was assessed by the sensitivity of Artemia salina larvae to different concentrations of the plant extracts studied. Testing for chemical compounds was performed on the basis of differential staining and precipitation reactions. The mean lethal concentration (LC50) was determined by the probit method. The qualitative phytochemical screening of the plants studied revealed the presence of catechic tannins, gallic tannins, flavonoids, anthocyanins and sterol-terpenes, alkaloids, saponosides, and reducing compounds. This composition varied according to the plants studied. Acute toxicity data indicated that there was no mortality and no structural and functional alterations of the liver and kidneys of treated animals. Larval cytotoxicity data suggest that the plants studied are not cytotoxic (LC50 ≥ 0.1 mg/mL). These observations reflect the safety of these plants and justify their use in traditional medicine in the treatment of many diseases including diarrheal diseases.