Antibacterial and Antioxidant Activities, in silico Molecular Docking, ADMET and DFT Analysis of Compounds from Roots of .

BACKGROUND

is a medicinal plant traditionally used to treat various ailments. Limited studies on inspired us to investigate the chemical nature and therapeutic potential of the plant.

METHODS

Silica gel column chromatographic separation was used for isolation. 1D and 2D NMR spectroscopic analysis and literature data were used for structural elucidation. Agar well diffusion assay was used for evaluation of antibacterial activity against , and . DPPH assay was used to evaluate radical scavenging activities. Molecular docking was done by AutoDock Vina 4.2 open-source program. DFT calculations were performed using the Gaussian 16 program package.

RESULTS

Dichloromethane/methanol (1:1) roots extract afforded a new hydroxyl-spongiane diterpenoid lactone derivative, 3-hydroxyisoagatholactone (), along with β-sitosterol () and ε-viniferin () whereas methanol extract afforded resveratrol (), gnetin H (), tricuspidatol A (), ε-viniferin-diol () and parthenostilbenin B (). At 50 μg/mL, compound recorded the highest inhibition against (8.55 ± 0.45 mm) and (9.30 ±1.39 mm). Against , compound consistently outperformed chloramphenicol (11.76 ± 0.77 mm, at 30 g/mL). Maximum binding affinity were observed by compound 3 against DNA gyrase B (-7.6 kcal/mol) where as compound 5 displayed maximum binding against PqsA (-8.8 kcal/mol) and S. aureus PK (-5.8 kcal/mol). Compounds and satisfy Lipinski's rule of five. resveratrol () demonstrated strong DPPH scavenging activity at 12.5 g/mL, with IC values of 0.052 µg/mL, compared to ascorbic acid (IC value of 0.0012 µg/mL).

CONCLUSION

In this work, eight compounds were identified from the roots extracts of including a new hydroxyl-spongiane diterpenoid lactone, 3-hydroxyisoagatholactone (). Compounds and exhibited good antibacterial activity and binding affinities. The docking result is in agreement with the antibacterial study. Overall, the study result suggests that the isolated compounds have the potential to be used as therapeutic agents, which supports the traditional uses of roots.