Phytochemical profile, antioxidant and antibacterial activities analysis of crude extract and essential oil of Pinus roxburghii and Pinus wallichiana: in vitro and in silico analyses

Pinus roxburghii and Pinus wallichiana are traditionally plants used for various medicinal purposes worldwide. The present study focused on evaluating the phytochemical compounds and the free radical scavenging potential in various parts of P. roxburghii and P. wallichiana through in vitro and in silico study. Crude extract of the fresh leaves was obtained using methanol while steam distillation method was used for the extraction of the essential oil. The phytochemicals were determined by standard methods. Antioxidant Potential of the phytochemicals was performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), Hydroxyl radical (OH) inhibition, Ferric ion reducing power (FRAP) and Phosphomolybedenum complex (PMC) assays. The interactions between the total phenolics and flavonoids of the selected plants and virulent target proteins of the pathogenic bacteria were identified, characterized, and examined using Molecular Operating Environment (MOE) software. The fresh leaves of P. roxburghii, exhibited the highest total phenolic (744.6 ± 27.0 mg GAE/100 g) and carotenoid content (21.4 ± 0.4 mg/g) that was significantly varied from other samples. The EO of P. wallichiana, showed the highest total flavonoid content. In P. roxburghii and P. wallichiana, the fresh leaves exhibited the highest percentage of scavenging potential against the DPPH radical. Additionally, the EO from P. roxburghii and P. wallichiana have significant potential to reduce ferric ions, and molybdate ions, respectively) with significant differences. The molecular docking showed a significant interaction of compounds present in these pines leaves with Exotoxin A and Elastase B proteins. The essential oil (EO), hydrosol (HS), and crude extract derived from P. roxburghii and P. wallichiana could be exploited as natural sources of antioxidants, anti-inflammatory agents, and innovative medications against the human pathogen, Pseudomonas aeruginosa.