GC-MS analysis and molecular docking of bioactive compounds of Camellia sinensis and Camellia assamica

The methanol extract of Camellia sinensis (MES) and acetone extract of Camellia assamica (AEA) were subjected to the thin layer chromatography to separate the bioactive compounds. The antimicrobial activity of all the fractions was carried out against pathogenic microorganisms by the agar-well diffusion method. The most effective bioactive fraction of each plant species was analysed by GC-MS. Fraction L of methanol extract of C. sinensis (MES) and fraction 5 of acetone extract of C. assamica (AEA) were found very effective against selected pathogenic strains. GC-MS analysis of this fraction showed the presence of n-heptadecanol-1 (68.63%) in MES and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) (17.58%) in AEA with the highest area. The compounds n-heptadecanol-1 and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether were used for docking to analyse its therapeutic potential. The ligand compound n-heptadecanol-1 (HEP) from MES of C. sinensis and 2',6'dihydroxyacetophenone, bis(trimethylsilyl) ether from AEA of C. assamica were docked with the target protein dihydropteoate synthase (DHPS) active sites of Escherichia coli and Staphylococcus aureus active sites via Auto Dock Vina, thereby forecasting the finest binding position of ligands. AutoDock Vina docked results revealed the involvement of binding energy for the establishment of the protein-ligand structure complex, besides generating an interpretation of all apparent molecular interactions accountable for its activity. Further, the protein-ligand complex of MES, EcDHPS + HEP and SaDHPS + HEP exhibiting the best binding affinity were - 4.8 kcal/mol and - 3.6 kcal/mol. The protein-ligand complex of AEA, i.e., EcDHPS + DHA and SaDHPS + DHA exhibited the best binding affinity of - 4.8 kcal/mol and - 4.8 kcal/mol.