Abstract:
Psidium guajava (Guava) is known to have diverse pharmacological propertites and numerous
varieties/cultivars of guava are widely available in Sri Lanka. However, no research on the
chemical compositions (CCs) and antioxidant activities of leaf essential oils (EOs) based on their
varieties have been reported so far. Especially, since antioxidants play a vital role in the
prevention of degenerative diseases, it is important to explore the antioxidative potential of
natural substances. Therefore, the purpose of this study was to investigate the antioxidant
activities and the CCs of EOs extracted from the leaves of seven guava varieties grown in Sri
Lanka, namely two wild varieties (Getta-pera and Embul-pera), Common-guava, Apple-guava
and three introduced varieties (Kanthi, Pubudu, and Costorican). The EOs were obtained by
hydro-distillation, and their CCs were investigated using GC-MS analysis. The hydro-distillation
yielded EOs of 0.44-0.04 percent (v/w). Each guava EO has a high concentration of
pharmacologically significant components, the amount of which varies according to the variety.
Nerolidol (7.9-70.2 %), D-Limonene (14.1-30.3 %), (-)-Globulol (7.0-21.0 %), Caryophyllene
(1.4-20.4 %), Eucalyptol (0.3-10.6 %), α-Pinene (0.2-8.0 %), α-Cubebene (0.7-6.1 %) are some
of the prominent compounds found in EOs. Nerolidol levels in Embul-pera were shown to be
high. D-Limonene and Eucalyptol were discovered to be rich in Kanthi. Getta-pera has high
levels of caryophyllene and α-Cubebene. (-)-Globulol was discovered to be abundant in Appleguava,
whereas α-Pinene was abundant in Costorican. Most noteworthy, 28 compounds which
include Isodurene, Cadinadiene-1,4, Allylbenzene, E,E-Farnesal, Epiglobulol, β-Maaliene,
Espatulenol were suggested for the first time in guava leaves’ EOs. EOs have antioxidant
capacities ranging from 329.56±2.01 to 85.70±2.01 μL Trolox Eq/L where P. guineense
exhibited stronger antioxidative ability than others. In a conclusion, the CCs and anti-oxidative
properties of guava varieties differ based on variety and 28 CCs were detected for the first time
in the EO of guava varieties cultivated in Sri Lanka.
