Chemical Composition and Antimicrobial Properties of Piper ovatum Vahl

The chemical composition of the essential oil obtained from the leaves of Piper ovatum Vahl by hydrodistillation was analyzed by GC–MS. The main constituents found were δ-amorphene (16.5 %), cis-muurola-4(14),5-diene (14.29 %) and γ-muurolene (13.26%). The crude extracts and isolated compounds were screened for their antimicrobial activity. Hydroalcoholic extracts of different parts of Piper ovatum Vahl, essential oil and amides isolated from leaves were tested against Gram-positive and Gram-negative bacteria and Candida species. All extracts and amides were active against Bacillus subtilis and Candida tropicalis, including clinical strains. Essential oil was active against C. tropicalis. These amides showed an inhibitory effect on the adherence of C. tropicalis ATCC 28707 on cover glasses at 10 µg/mL, but did not show morphological alterations at the tested concentrations. Amides were identified as piperovatine and piperlonguminine, and showed MIC values of 15.6 and 31.2 µg/mL to B. subtilis and 3.9 µg/mL to C. tropicalis, and low toxic effects to Vero cells and macrophages.