BIOACTIVE COMPOUND ANALYSIS AND BIOACTIVITIES OF ENDOPHYTIC BACTERIA FROM CISSUS QUADRANGULARIS

Endophytic bacteria were isolated from the stem of Cissus quadrangularis on Nutrient agar medium. The bacterial isolates were cultured in Nutrient broth. Ethyl acetate extracts of endophytic bacteria were evaluated for the presence of bioactive compounds and total phenolic content. The phytochemical screening of extracellular ethyl acetate extracts showed the presence of phenols. The total phenol content in the extracellular extract of a bacterium labeled as CqB9 was found to be 7.05 ± 0.13 mg/g. The extracellular crude extract of CqB9 displayed considerable antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae. GC-MS analysis of CqB9 extract revealed several peaks indicating the presence of different secondary metabolites having bioactive potential. The extract of CqB9 was found to possess antioxidant activity with an IC₅₀ value of 157.5 ± 0.4 µg. The cytotoxic activity using MTT assay showed that the crude extract inhibited the proliferation of the MCF-7 cell line in a dose-dependent manner. CqB9 was found to be similar to Achromobacter anxifer by 16S rRNA sequencing. The bioactive components such as phenols and those predicted by GC-MS may contribute to the bioactivities of the isolate. The results reveal that the endophytic bacterium isolated from Cissus quadrangularis has the potential to produce bioactive compounds. The endophytic bacteria and the metabolites produced by them need to be explored further for potential source and novel natural bioactive compounds.