Comparative phytochemical analyses of methanolic and aqueous leaf extracts of three medicinal plants used in plant disease control

Thesis Abstract

Investigations were conducted to determine the qualitative and quantitative phytohemical properties of methanolic and aqueous leaf extracts of Chromolaena odorata L., Carica papaya L., and Ocimum gratissimum L. using standard methods. The results revealed that alkaloids, saponins, flavonoids, glycosides, reducing sugars, carbohydrates, steroids, tannins and terpenoids were present in all the test plants. However, methanolic leaf extract of C. odorata had the highest amounts of saponins, flavonoids and steroids and lowest tannins content. Carica papaya had highest content of alkaloids, carbohydrates and terpenoids and lowest content of glycosides, reducing sugars and steroids, while O. gratissimum had highest composition of glycosides, reducing sugars and tannins and lowest composition of alkaloids, saponins, flavonoids, carbohydrates and terpenoids. Comparisons on the aqueous leafr extracts of the test plants showed that C. odorata had the highest composition of glycosides and tannins and lowest composition of saponins, flavonoids and steroids. Carica papaya had the highest amounts of flavonoids and terpenoids and lowest composition of alkaloids, glycosides, carbohydrates and tannins, while O. gratissimum had the highest contents of alkaloids, saponins, reducing sugars, carbohydrates and steroids, and lowest composition of terpenoids. The compositions of the leaf extracts were significantly different at P ≤ 0.05. The significance of the test plants and the importance of these phytochemicals were discussed with respect to the roles they play in plant disease control.