Chemical Reconfiguration of Ocimum basilicum Stem Biomass by Infrared Processing and its Impact on Antimicrobial and Antioxidant Activities

Abstract

This study evaluated the effect of controlled IR irradiation on the phenolic profile, and bioactivities of Ocimum basilicum stem biomass extract. Polyphenolic profiling was performed using HPLC. Antimicrobial activity was assessed using agar diffusion and Time–kill kinetics. Antioxidant activity was evaluated using DPPH assay. HPLC analysis revealed increased chlorogenic acid and rosmarinic acid after IR treatment. MIC values decreased fourfold for E. faecalis and P. aeruginosa, and twofold for S. aureus and C. albicans. Time–kill assays showed accelerated bactericidal activity, with complete eradication within 3 h for most strains following IR treatment. Antioxidant activity and antihemolytic protection were also enhanced changed to: IR treatment enhanced antioxidant activity, reducing the IC₅₀ from 9.52 ± 0.78 to 6.55 ± 0.03 µg/mL, while antihemolytic protection increased from 32%, 51%, and 68% to 46%, 69%, and 84% at 25%, 50%, and 75% MIC, respectively. Controlled IR irradiation selectively modulated the phenolic content of O. basilicum stem extract, resulting in measurable enhancement of antimicrobial and antioxidant performance. These findings suggest that IR treatment may be a useful approach for modifying the phytochemical and functional properties of plant extracts, although the contributions of IR-specific and thermal effects require further investigation.