Composition, Antibacterial Efficacy, and Anticancer Activity of Essential Oil Extracted from Psidium guajava (L.) Leaves.

Essential oils (EO) are used as a natural remedy to treat various chronic diseases, although clinical evidence is lacking. In this context, we have endeavored to measure the percentage of chemical composition and biological efficacy of Psidium guajava (guava) leaf essential oil in treating oral infections and oral cancer. The essential oil obtained from hydrodistillation of P. guajava L. leaves was analyzed by gas chromatography–mass spectrometry (GC–MS). The activities of selected oral pathogens Candida albicans (C. albicans) and Streptococcus mutans (S. mutants) were studied in vitro and in silico. MTT assay was used to test for anticancer activity against human oral epidermal carcinoma (KB). GC–MS showed that the main components of PGLEO were limonene (38.01%) and β-caryophyllene (27.98%). Minimum inhibitory concentrations (MICs) of 0.05–0.1% were demonstrated against C. albicans and S. mutans. Antimicrobial activity against C. albicans and S. mutans, as shown by molecular linkage analysis, revealed that the main metabolites, limonene and β-caryophyllene, potentially inhibited the receptors of C. albicans and S. mutans. PGLEO showed significant (p < 0.001) anticancer activity (45.89%) at 200 µg/mL compared to doxorubicin (47.87%) with an IC₅₀ value of 188.98 µg/mL. The outcomes of the present study suggest that PGLEO has promising antimicrobial and anticancer activities and could be a useful source for developing a natural therapeutic agent for oral infections and oral cancer. [ABSTRACT FROM AUTHOR]