In Vitro Anti - Plasmodial Activity Of The Crude Extracts Of Phyllanthus Sepialis And Rumex Steudelii

Abstract

Background: Malaria is a disease of high morbidity and mortality, especially in children under five and adults with low immunity. According to the World Health Organization (WHO) Malaria report 2018, there is an average of four million annual malaria incidences in Kenya, with a mortality rate of 5.1% among patients admitted with severe malaria. Drug therapy and vector control are the main modes of malaria control in the absence of an effective vaccine, however, with a growing concern of emerging multidrug- resistant malaria parasites, there is a need to explore for new and effective anti- malarial agents. In this regard, this study involves plant extraction and in vitro investigations of anti- plasmodial activity of two medicinal plants; Phyllanthus sepialis and Rumex steudelii, plants that have been traditionally used in the management of malaria in Kakamega County, Kenya (Mukungu et al., 2016). Objective: The aim of this study was to establish the phytochemical classes of Phyllanthus sepialis secondary metabolites and assess the in vitro anti - plasmodial activities of P. sepialis and Rumex steudelii. Methods: The two plants were chosen for study through literature review whereby both of them were reported to be used in treatment of malaria in Kakamega County, Kenya. The leaves of P. sepialis and the roots of R. steudelii were collected from Machakos and Nairobi Counties, respectively. They were then air dried, milled and extracted using distilled water, methanol, hexane, dichloromethane and ethyl acetate, separately. P. sepialis plant powder was subjected through various documented phytochemical tests to establish the presence of saponins, tannins, alkaloids, flavonoids, triterpenes, terpenoids, phenols and anthraquinones. The anti- plasmodial activities of all extracts were determined using P. falciparum in vitro assessment using light microscopy and flow cytometry. The light microscopy assay involved prepared Giemsa- stained microscope slides that were viewed under a light microscope. The infected erythrocytes were counted and documented against the total number of erythrocytes in the field. The flow cytometry assay involved staining the parasite DNA with fluorescent dye, SYBR Green I, and counting the number of viable parasites using a FACS caliber equipment. Parasitemia was then generated using the protocols of FlowJo software and IC50 values calculated using Microsoft Excel (2016). Results: Rumex steudelii is known to contain tannins, phenols, saponins and terpenoids; while Phyllanthus sepialis was found to contain phenolic compounds, triterpenes, terpenoids and tannins present. In both tests R. steudelii, especially the non-polar secondary metabolites, were found to have activity against the Plasmodium falciparum parasite, as indicated by the IC50 values of hexane, dichloromethane and ethyl acetate extracts. The water extract also exhibited activity. P. sepialis also showed activity against p. falciparum, with the dichloromethane, methanol, water extracts having moderate anti - plasmodial activity. Conclusion: The Luhya community of Kakamega County in Kenya have traditionally used P. sepialis and R. steudelii to treat malaria. This study has confirmed that these plants do inhibit P. xiv falciparum growth in vitro, and specifically the active fractions can be found in the leaves and roots of P. sepialis and R. steudelii, respectively.