PHYTOCHEMICAL SCREENING, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF PAPAYA (C. papaya L.) LEAF AND SEED EXTRACTS

Abstract

Papaya (C. papaya) is a medicinal plant due to its specific enzymes and bioactive compounds. Besides its nutritional properties, leaves and seeds are the most useful part among all used parts for the medicinal purpose. The present study is undertaken to investigate phytochemical screening, antioxidant and antimicrobial activities of aqueous and methanol extracts of papaya leaf and seed. The qualitative screening of phytochemicals was conducted using water and methanol as solvents. The antioxidant potentials were based on phenolic content and free radical scavenging activities of total antioxidant capacity and hydrogen peroxide scavenging activities. The antimicrobial experiment involved 2 source extracts, 2 solvent system, 4 test organisms in a completely randomized factorial design in three replications.in such a way that it describes the determination of antimicrobial and antioxidant activities. The result of phytochemical analysis revealed the presence of alkaloids, saponins, flavonoids, tannins, terpenoids ,phlobatannins and steroids in aqueous extracts and absence of alkaloids and terpenoids in methanolic extracts. The methanolic leaf extracts presented slight detection for saponnins and flavonoids; moderate detection for phlobatannins; high detection for tannins; and no detection for alkaloids and terpenoids. The methanolic seed extract has exhibited slight detections only for saponins and terpenoids.. Significantly,the higher hydrogen peroxide scavenging activity (HPSA) was recorded for seed methanol extract (42.66%) as the least HPSA was observed for the leaf aqueous extract (24.84%). The highest concentration of the crude extracts (200mg/L) presented the strongest antibacterial activity with the maximum zone of inhibition (18.83mm) for papaya leaf methanolic extract against S. aureus. The maximum zone of inhibition 17.90mm for leaf methanolic extract against A. versicolor..The methanolic leaf extract has presented the strongest antibacterial activity with minimum inhibitory concentration MIC (4.68mg/L) and corresponding minimum bactericidal concentration MBC (12.5mg/L) against S. aureus. The strongest antifungal activity with MIC (9.38mg/L) and corresponding minimum fungicidal concentration MFC (25mg/L) was recorded for methanol leaf extract against A. versicolorThe result of the present study indicated that aqueous extracts have presented better phenolic content and total antioxidant capacity than methanol extract. The result of the present study revealed considerable antimicrobial activities of the plant extracts. Future studies should be conducted to test the antimicrobial experiment with various multidrug resistant microbes;