Herbal medicine use in murang’a county and antiflea activity and safety of tithonia diversifolia and senna didymobotrya extracts

Abstract

Herbal medicines have been used for a long time to control various human and animal diseases in the world. There is limited published information on the use of herbal medicines in Murang’a County of Kenya, despite the County having large and diverse species of plants claimed to have medicinal value in the literature. Tithonia diversifolia and Senna didymobotrya have been reported to have medicinal value. While T. diversifolia is used to control jigger fleas in Kakamega County of Kenya; both plants are used in the management of constipation, abdominal pain, diarrhoea, malaria, diabetes mellitus and microbial ailments. The objectives of this study were to investigate and document the use of herbal medicines in Murang’a County, and also to investigate antiflea activity and safety of Tithonia diversifolia and Senna didymobotrya. Questionnaires were used to interview a total of 28 herbalists for ethno-medical uses of the plants. A total of 119 plant specimens were collected after feedback from the herbalists. The plants were identified, mounted, allocated voucher numbers and stored in the herbarium at East Africa Herbarium. Fifty nine (50%) plants were used by the herbalists for the treatment of more than one disease condition, and they were also used by two or more herbalists for the treatment of same condition. Tithonia diversifolia and Senna didymobotrya were selected for the purpose of this study. The two plants specimens were collected from Murang’a County. Each plant part claimed to have antiflea activity was extracted by maceration using methanol and water, for methanol and aqueous crude extracts respectively. The crude extracts were tested for the in vitro activity using fleas obtained from dogs as a model for the other types of fleas like Tunga penetrans and the activity compared with those of pyrethrum flowers crude extracts. A total of ten fleas were placed in each of the 15 ml polypropylene centrifuge tubes which were fitted with a split filter paper pre-coated with aqueous extract. The extract were thereafter investigated for in vitro activity and the extracts which were active were used for the study of acute toxicity, dermal irritation, sensitivity and eye irritation tests, using standard methods. Data was analyzed using Microsoft excel and in vitro antiflea activity data was analyzed using Student’s t-test, R version 3.4.3(2017-11-30). The acute toxicity was evaluated using OECD guideline 425. Tithonia diversifolia flowers extract had antiflea activity (93.3%) which was similar to that of pyrethrum flowers (90%), and it was only slightly toxic with LD50 of above 10,000 mg/kg body weight. Senna didymobotrya had lower antiflea activity (66.3%) when compared to Tithonia diversifolia leaves which had antiflea activity of 86.7% and also had more toxic effects on blood profile. The findings of this study increases the knowledge of herbal medicines used in Murang’a County, and fleas control and the plants can be studied further for the control of Tunga penetrans infestation in humans.