Comparative Phytochemical Analyses of Methanolic and Aqueous Leaf Extracts of Three Medicinal Plants Used in Plant Disease Control.


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 leaf 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. 


A large number of chemicals have been developed for the control of plant diseases, but due to the growing awareness of the hazardous side effects of these chemicals, more emphasis is given to the use of biocontrol agents. One of the major challenges in the field of Plant Pathology is the need for some ecofriendly and safe alternative control strategies for agriculture, which has led researchers to turn their attention to plant extracts as sources of biocontrol agents.

Therefore, growing of most plants and tress now goes beyond afforestation purposes to making them available and accessible for exploitation for their natural chemical composition vis-à-vis their usefulness in the management and cure of both plant and animal diseases. These chemical compounds, known also as phytochemicals, provide defenses for the plants against diseases and other environmental factors.

It is now evident that most of these plant chemicals could also be helpful in the treatment of both animal and human diseases. These phytochemicals which are bioactive include alkaloids, flavonoids, steroids, saponin, tannins, terpenoids, glycosides and other phenolic compounds classified as most important (Edeoga et al., 2006). Most of these phytochemicals are used in the control of animal and plant diseases for their rich composition, which provides both preventive and curative properties. 


Adekunle, A.A and Uma, N.U. (2000). Effect of benlate solution, crude leaf extracts of
Azadirachta indica and Ocimum gratissimum on growth of fungi and preservation
of melon seeds. (Unpublished) M.Sc Thesis University of Lagos, Nigeria. 120 pp.

Adebiyi, A., Adaikan, P.G., Prasad, R.N.V. (2002). Papaya (Carica papaya) consumption
is unsafe in pregnancy: Fact or fable? Scientific evaluation of a common belief
in some parts of Asia using a rat model. British Journal of Nutrition, 88: 199-203.

Agrios, G.N. (2005). Plant Pathology. (5th edition), Academic Press, New York. 922 pp.

Akah, P.A., Oli, A.N., Enwerem, N.M., and Gamaniel, K. (1997). Preliminary studies on
purgative effect of Carica papaya root extract. Fitoterapia, 68 (4), 327-331.

Akueshi, C.O., Kadiri, C.O. Akueshi, E.U. Agina, S.E. and Ngurukwu, C. (2002).
Antimicrobial potential of Hyptis sauveolens (Lamiaceae). Nigerian Journal of
Botany, 15:37-41.

Amadioha A.C. (2000). Controlling rice blast in-vitro and in-vivo with extracts of
Azadirachta indica A Juss. Crop Protection, 19: 287–290.

Amadioha, A.C. (2002). Fungitoxic effects of extract of Azadirachta indica against
Cochliobolus miyabeanus causing brown spot disease of rice. Phytopathology, 35:

Amadioha, A.C. and Uchendu, P.N. (2003). Post-harvest of tomato fruit rot caused by
Fusarium solani with extracts of Azadirachta indica. Discovery of Innovation, 15
(1/2): 83-86.

StudentsandScholarship Team.

By admin

Leave a Reply

Your email address will not be published. Required fields are marked *