Phytochemical Screening and Antimicrobial Activities of Azadirachta Indica (NEEM)

Chong, Kim Yen (2016) Phytochemical Screening and Antimicrobial Activities of Azadirachta Indica (NEEM). Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Azadirachta indica also known as neem was found to exhibit various pharmacological activities including antimicrobial activity. In this study, both ethanolic and aqueous extracts of neem leaves which were subjected to phytochemical screening and thin layer chromatography showed the presence of secondary metabolites including alkaloids, phenols, flavonoids, terpenoids, diterpenes, carbohydrates and glycosides but not tannins and saponins in neem. In this study, ethanolic extract showed antimicrobial effect against Escherichia coli and the percentage of inhibition of growth reached 40% in 1.5 hours of incubation at concentration of 11.9 mg/ml. This inhibition increased to 52% when the dosage increased to 23.26 mg/ml. The results also indicated that the ethanolic extract was only effective to inhibit the E. coli in the first 2.5-3 hours of incubation. On the other hand, ethanolic extract was found to be effective against Staphylococcus aureus. The percentage of reduction in growth reached up to 90% and 95% respectively in the first 15 minutes of incubation when 11.63 mg/ml and 22.73 mg/ml of extract were used. The inhibition of growth remained after 0.5 hour of incubation in which the percentage of reduction was found to be 95% and 99%. After 1st hour of incubation, no further growth was observed in S. aureus when both concentrations were used. However, the ethanolic extract with concentration of 11.9 mg/ml and 23.26 mg/ml has no significant difference (p > 0.05) on the antibacterial activity for E. coli. This is similar to S. aureus when the concentrations used were 11.63 mg/ml and 22.73 mg/ml. In this study, the type of extraction solvents used showed significant effect (p < 0.05) on antibacterial activity. Aqueous extract was found to be less effective compared to ethanolic extract as the percentage of inhibition of growth by 11.63 mg/ml and 22.22 mg/ml of aqueous extract on E. coli reached 6 % and 9 % at 0.5 hour of incubation and no reduction was observed after 1 hour of incubation. There was significant difference (p < 0.05) of concentration of aqueous extract on the growth of S. aureus but not E. coli. The inhibition of S. aureus by 11.36 mg/ml of aqueous extract reached 21 % in 0.5 hour of incubation. 21.74 mg/ml was found to have relatively more effective and longer inhibition time as 37 % of reduction was observed at 1st hour of incubation. The results also showed that the aqueous extract was effective in the first 1.5 – 2 hours of incubation. Overall, the effect lasted until 0.5 hour for E. coli and 2 hour for S. aureus. In conclusion, neem extract was found to be more effective against S. aureus if compared to E. coli.