Ethnobotanical Documentation, Phytochemistry, and Cytotoxicity of Anti-snakebite Envenomation Plants of Mwingi West Sub- County, Kenya

Abstract

Snakebite envenomation (SBE) is a life-threatening Public health problem affecting over 2.7 million persons annually globally, and the greatest burden lies in the developing world. Despite the successful management of SBE by antivenom therapy in conventional medicine, it is of low efficacy due to the diverse venom composition across snake types, limiting its usefulness. As a result, inhabitants of the Sub-Sahara region, where Snakebite envenomation incidence is high, utilise medicinal plants as an alternative to manage SBE and associated complications. However, there is scanty of ethnomedical and empirical information available for many medicinal plants with longstanding usage in traditional medicine, especially those used against SBE. In Kenya, Kitui C5ounty records the highest incidence rates of SBE, attributable to the agricultural activities of inhabitants, their housing type, and semi-arid climate. Due to the unaivailability, unaffordability, and inaccessibility of conventional antivenom therapy for Snakebite envenomation for victims, the locals utilize medicinal plants as a viable alternative to manage Snakebite envenomation. However, there is no sufficient ethnomedical documentation of these plants, which can foster empirical investigations, and heritage. Therefore, the objective of the current study was to investigate and document plants used to manage snakebite in Migwani Ward, Mwingi West Sub County, Kitui County, and determine their qualitative phytochemical composition and their cytotoxicity. Ethnobotanical survey to document medicinal plants used to manage SBE in the study area was done between January and February 2021. Ethnobotanical data was collected from 45 purposefully selected respondents from the ward using semi-structured questionnaires, field walks, and oral interviews. Voucher specimens of cited plants were collected with the help of respondents, identified with the help of botanists, and deposited at the East Africa herbaria of the National Museum of Kenya. Using Relative Frequency of Citation criteria. The four xii medicinal plants which were selected, includes Entada leptostachya Harms, Senna sengueana (Delile) Lock, Securidaca longipendunculata, and Strychnos henningsii Gilg were selected, extracted using water, methanol, and dichloromethane, and analysed for qualitative phytochemical composition and cytotoxicity on brine shrimp nauplii. In this study, 14 medicinal plants which are used to manage Snakebite envenomation were documented. Four plant materials with the highest Relative Frequency of Citation, included Entada leptostachya Harms-stem bark (0.58), Senna singuenna-Roots (0.53), Securidaca longipendunculata-Roots (0.36), Strychnos henningsii-Stem bark (0.46) were selected for phytochemical analysis and cytotoxicity assay. Qualitative phytochemistry revealed antiSnakebite envenomation associated phytochemicals such as alkaloids, saponins, tannins, phenols, and flavonoids in the aqueous and methanolic extracts of selected plants. However, the tested phytochemicals were not detected in dichloromethane extracts of all the extracts. The effects of the documented plants could be attributable to these phytochemicals. Furthermore, the aqueous and methanolic extracts of Strychnos henningsii, Entada leptostachya, and Senna singuenna had LC50>1000μg/ml and were non-cytotoxic. However, Securidaca longipendunculata had an LC50<1000μg/ml, which was considered slightly cytotoxic. Further empirical investigations to determine the anti-SBE efficacy of Strychnos henningsii, Entada leptostachya, Senna singuenna, and Securidaca longipendunculata should be conducted to validate their ethnomedicinal claims. Also, the bioactive phytochemicals of the studied plant extracts, their mode(s) of bioactivity and their safety should be investigated furthe