Composition, Chemical Fingerprinting and Antimicrobial Assessment of Costa Rican Cultivated Guavas (Psidium friedrichsthalianum (O. Berg) Nied. and Psidium guajava L.) Essential Oils from Leaves and Fruits

Abstract

The essential oil of two related tree species, P. friedrichsthalianum and P. guajava, where obtained. A total of six different oil samples were recovered including leaves in dry/rainy season and fruits of both plant species. Oil yields ranged between 0.128% (P. friedrichsthalianum leaves during dry season)-0.743% (P. guajava leaves during rainy season). All exts. were subjected to a GC/MS anal. using, during the chromatog. sepn., a polyethylene glycol column. In general terms, we recognized three independent biosynthetic routes i. arom. compds. ii. Terpenes and iii. Fatty acids derivs. Several compds. were found to be preserved in the oils, such as 2,4-ditert-butylphenol, α-terpineol and neointermedeol whereas Costa Rican guava fruit exhibit unique compds. such as 2H-pyran-2,6-(3H)-dione. Terpenes and fatty acids are among the most variable (p<0.005) in content when comparing dry season with rainy season leaves. Finally, based on profiling, a descriptive PCA anal. showed three related groups and that Costa Rican guava fruit oil as the most different in terms of compn. Herein we report more than 50 compds. for each species and relative percentages of major components (>0.1%) and trace compds. In addn., we evaluated the antimicrobial activity of these essential oils against common foodborne and food-spoilage related bacteria. The rainy season P. guajava leafs' presented the highest antimicrobial activity against all the bacteria strains tested, with inhibition zones ranging from 31 to 52 mm. This study will help understand volatile compn. of a fruit producing plant native from this geog. area and hints toward possible applications. [on SciFinder(R)]