In Vitro Antioxidant Activities Of Methanolic Extracts Of Caesalpinia Volkensii Harms, Acacia Hockii De Wild And Vernonia Lasiopus O. Hoffm

ABSTRACT

Antioxidants are chemical substances that inhibit oxidation (oxidation is a chemical reaction that can produce free radicals, leading to a chain reaction that may damage cells or other molecules) Free radicals are reactive oxygen species and reactive nitrogen species generated by our bodies naturally during normal metabolic functions. If free radicals overwhelm the body ability to regulate them, a condition known as oxidative stress ensues. Oxidative stress leads to the destruction of biomolecules such as lipid membranes leading to lipid peroxidation which is responsible for the pathogenesis of various disease conditions such as cancer, hypertension, and cardiovascular diseases. Hence the application of an external source of antioxidant can assist in coping with the treatment of this oxidative stress. Research on natural antioxidant has gained interest in the recent past as demand for safer and readily available antioxidant by food industries and preventive medicine has gained momentum. This study was carried out to determine the in vitro antioxidant potential of Methanolic extracts of Caesalpinia volkensii, Acacia hockii and Vernonia lasiopus. The plant samples were collected with the help of local herbalists in Embu County, Kenya and transported to Kenyatta University Biochemistry and Biotechnology laboratories for cleaning, air drying, milling, and extraction using methanol as a solvent. The antioxidant activities of the extract were evaluated through the scavenging effect of 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2) and total ferric reducing power. The antioxidant data obtained was assayed against that of the standard (Ascorbic acid). All the extracts demonstrated significant DPPH scavenging activities with the highest percentage of 87.22% for ascorbic acid and 82.73%, 76.86%, 67.36% for A. hockii, V. lasiopus and C. volkensii respectively. Ascorbic acid which was used as a standard demonstrated lowest IC50 of 0.198. The IC50 for the plant extracts were 0.601, 0.40 and 0.47 for C. volkensii, A. hockii and V. lasiopus respectively. They also demonstrated reducing the power that increased with increase in extracts concentration. In hydrogen peroxide assay increase in extracts, the concentration decreased the scavenging activity for all the extracts. There was a significant difference between the extracts and the standard. The methanolic extracts of Caesalpinia volkensii, Acacia hockii and Vernonia lasiopus demonstrated significant antioxidant activity. Qualitative phytochemical screening indicated the presence of secondary metabolites associated with antioxidant activities. The present study therefore validates and supports the traditional use of Caesalpinia volkensii, Acacia hockii and Vernonia lasiopus in management of oxidative stress and recommends further research for the development of phytomedicine with antioxidant properties.