GC-MS Profiling, Antimicrobial Activity of Annona squamosa: An In-silico and Inv-itro Approach.

Annona squamosa Linn. (Annonaceae) is a perennial plant that possesses anti-diabetic, antioxidant, anti-tumor, analgesic, and antimicrobial activity. The current study was designed to explore the phytochemicals using GC-MS analysis and to evaluate the antimicrobial activity followed by in-silico molecular docking study. The leaf powder of A. squamosa was successively extracted with n-hexane and methanol. The n-hexane fraction was subjected to GC-MS analysis. The extract was evaluated for antimicrobial activity to determine the zone of inhibition by disc diffusion method at concentrations of 12.5, 25, and 50 mg/ml. The minimum inhibitory concentration was performed at 100, 50, 25, 12.5, 6.25, 3.12 and 1.56 mg/ml concentration, against gram-positive bacteria (Staphylococcus aureus ATCC-25923, Staphylococcus aureus ML-267, Staphylococcus aureus ATCC-29737, Staphylococcus aureus ATCC-29157, Bacillus subtilis-6633), and gram-negative organisms (Escherichia coli PBR-332, Escherichia coli JM-109, Klebsiella pneumoniae PB-12) using streptomycin (1 mg/ml) as standard. Insilico docking was carried out with AUTO-DOCK Tool 1.5.6 using Discovery Studio 3.5. The GC-MS study revealed 13 compounds, the major compounds were 16-hentriacontanone (41.95%); [(1R,2S,6S,7S,8S)-8-Isopropyl-1-methyl-3-methylene-tricyclo-[4.4.0.02,7]-decane] (15.91%) and caryophyllene (12.07%). The better zone of inhibition was found at a concentration of 50 mg/mL against all organisms whereas the Minimum Inhibitory Concentration was detected at 6.25 mg/mL. The docking results revealed through Auto-Dock tool, a highest docking score of -5.2 each obtained from both the compounds caryophyllene and [(1R,2S,6S,7S,8S)-8-Isopropyl-1-methyl-3-methylenetricyclo-[4.4.0.02,7]-decane], which was compared to the that of standard trimethoprim as reported previously. The antimicrobial potential of A. squamosa leaf might be attributed to the synergistic influence of bioactive components identified from GC-MS analysis. [ABSTRACT FROM AUTHOR]