Comparative Chemical Characterization, Biological Activities, and Molecular Docking Analysis of Ethanolic Extracts from Guava and Lemon Leaves

In this study, ethanolic (70%) extracts of guava (GLE) and lemon (LLE) were prepared, and their major phenolic compounds were identified using HPLC. Biological activities of both extracts were evaluated through antioxidant assays (DPPH, β-carotene linoleic acid, and FRAP), cytotoxicity tests (MTT assay and apoptosis-related gene expression), antiviral activity against HSV-2, and antibacterial analysis. In silico molecular docking was performed to assess the interaction of identified phenolic compounds with apoptosis-related proteins. Gallic acid was predominant compound, followed by caffeic acid, chlorogenic acid, and naringenin. Antioxidant analysis showed that GLE exhibited significantly stronger activity than LLE, with higher radical scavenging capacity (DPPH 88.28%), protection index (81.78%), and FRAP value (2.99 OD700). Both extracts reduced cancer cell viability, with A549 cells being most sensitive. Gene expression analysis indicated apoptosis induction through upregulation of BAX and downregulation of BCL2, particularly in GLE-treated cells. Antiviral evaluation against HSV-2 demonstrated stronger inhibition by LLE (61.83%) compared with GLE (51.58%). Antibacterial assays showed broad-spectrum activity, with LLE more effective against S. aureus and E. coli, while GLE showed stronger inhibition against K. pneumoniae. Molecular docking highlighted rutin and naringenin as key compounds interacting with BAX and BCL2, supporting their potential antioxidant, antimicrobial, antiviral, and anticancer properties.