Phytochemical and antimicrobial study of Alstonia scholaris leaf extracts against multidrug resistant bacterial and fungal strains

Abstract

In the present study, Alstonia scholaris leaves were explored for phytochemical constituents, antibacterial and antifungal potentials. Phytochemical screening of the extracts established the presence of glycosides, alkaloids, saponins, terpenoids, anthraquinones, reducing sugars and steroids which later on confirmed through fourier transform infrared spectroscopic analysis. The extract was applied against eight multidrug resistant bacterial and five fungal strains using standard protocols. Methanol and ethyl acetate extracts of the leaves showed highest diameter of inhibition zone (DIZ) of 28mm and 26mm respectively against Enterobacter. Ethanolic extract exhibited prominent DIZ of 26.33mm and 23.67mm against Enterobacter and Pseudomonas respectively. The n-Hexane extract showed DIZ of 23.67mm against Enterobacter. Aqueous extract showed 19.33mm DIZ against methicillin resistant Staphylococcus aureus. Similarly, the n-hexane extract showed highest DIZ of 20.33mm against Aspergillus fumigatus and this activity was highly effective than the control. Ethyl acetate extract showed 18.67mm DIZ against Aspergillus niger whereas methanolic extract showed marked inhibition against Rhizopus and Acremonium with a DIZ of 20mm and 17.03mm respectively. The current study on A. scholaris unveils about the presence of valuable phytochemicals in it having significant antimicrobial properties and further suggests to investigate for the minimum inhibitory concentration (MIC) value of the extracts in prospective research.