Chemical composition and antimicrobial activity of the essential oil of senescent leaves of guava (<i>Psidium guajava</i> L.)

Abstract

The aim of the study was to investigate the chemical composition and antimicrobial activity of the essential oil of the senescent leaves of <i>Psidium guajava</i> L. (Myrtaceae). The hydrodistilled essential oil of the leaves was analysed by GC-FID and GC-MS. The antimicrobial activity of the oil was assessed against human and plant pathogenic microorganisms by disc diffusion, microdilution broth and poison food techniques. A total of forty-six constituents, representing 90.9% of the total oil composition were identified. Major constituents of the oil were limonene (29.1%), (<i>E</i>)-caryophyllene (15.7%), caryophyllene oxide (8.8%), caryophylla-4(12),8(13)-dien-5-ol (6.5%), (<i>E</i>)-nerolidol (4.0%), <i>α</i>-cadinol (3.4%), and muurola-4,10(14)-dien-1-<i>β</i>-ol (2.5%). The chemical composition of the examined essential oil was quite different from those reported earlier. The essential oil showed significant inhibition of human pathogenic bacteria (MIC: 0.065-0.261 mg/mL) and plant pathogenic fungi, namely <i>Curvularia lunata</i> (86.02%) and <i>Fusarium chlamydosporum</i> (82.80%).