Seasonal Variation in Volatile Oil, Polyphenol Content and Antioxidant Activity in Extract of Laurus nobilis Grown in Iran

Abstract

The leaves of Laurus nobilis were collected in the middle of four seasons (spring, summer, autumn, and winter) to determine the best harvesting time for obtaining the highest oil yield, 1,8-cineole and polyphenol content and antioxidant activity. After drying the plant materials in shade, their EOs (essential oils) were obtained by hydro-distillation method. Analysis of variance showed harvesting time had significant effect on the oil yields of L. nobilis. Seventy one components were identified in the oils of L. nobilis with 1, 8-cineole (5.7%--terpinyl acetate (3.2%-13.1%), sabinene (2.3%-12.0%), beta-elemene (0.2%-17.7%) and (E)-caryophyllene (0.2%-16.9%) as the main constituents in different seasons. The predominant phenolic constituents in L. nobilis were cinnamic acid, carvacrol, quercetin and coumarin, respectively. Gallic acid, catechin, caffeic acid, chloregenic acid, p-Comaric acid and rutin were not detected in any seasons. The best antioxidant activity was in spring (268.6 µg/mL) and the lowest one was in winter (702.1 µg/mL).