Phytochemical Screening and Bioactivity Evaluation of Volkameria inermis Flower Essential Oil: Antioxidant, Anti-Inflammatory, and in-silico ADMET Studies

Abstract

Medicinal plants remain a cornerstone of natural product-based drug discovery due to their capacity to produce structurally diverse and pharmacologically active metabolites. Volkameria inermis (L.) is a coastal medicinal shrub with extensive ethnopharmacological use and rich phytochemical diversity, yet its floral essential oil remains largely underexplored despite its potential therapeutic significance. The present study explored the phytochemical composition, antioxidant, anti-inflammatory, and molecular docking potential of the flower essential oil of Volkameria inermis. GC-MS analysis identified 34 volatile constituents, with the oil being rich in linalool (24.52%), followed by 1,6-hentriacontanone (13.48%), n-hexacosane (10.68%), 1-octen-3-ol (8.77%), and n-pentacosane (8.59%), indicating the predominance of oxygenated monoterpenes and long-chain hydrocarbons. The essential oil showed a clear concentration-dependent antioxidant activity, reaching 70.54±0.16% DPPH radical scavenging and 72.22±0.27% hydrogen peroxide scavenging at 100 µL/mL, with IC50 values of 64.93±0.02 and 64.53±0.02 µL/mL, respectively. A significant anti-inflammatory effect was also observed in the protein denaturation assay, where the oil produced 62.70±0.24% inhibition at 100 µL/mL with an IC50 of 73.50±0.29 µL/mL. The molecular docking studies supported these biological findings. In antioxidant docking with superoxide dismutase (SOD), (E)-nerolidol showed the strongest interaction (-6.5 kcal/mol), followed by fokienol (-5.9 kcal/mol), eugenol (-5.5 kcal/mol), α-terpineol (-5.5 kcal/mol), and linalool (-5.1 kcal/mol), showing affinities comparable to the standard antioxidants. In anti-inflammatory docking, (Z)-lanceol acetate showed the highest binding with COX-1 (-8.4 kcal/mol), while α-copaene displayed the strongest COX-2 interaction (-7.7 kcal/mol), supporting the observed inhibition of protein denaturation. Overall, the combined GC-MS, antioxidant, anti-inflammatory, and docking results suggest that the flower essential oil of V. inermis is a promising natural source of bioactive antioxidant and anti-inflammatory compounds, with linalool-rich terpenoids and sesquiterpenes playing major roles in the observed activity.