Screening of Chemical Composition, in vitro Antioxidant, α-Amylase and α-Glucosidase Inhibitory Activities of the Leaf Essential Oils of Cinnamomum wightii from Different Populations

Abstract

Cnnamomum wightii is an endemic species of the Western Ghats, India and is used in Ayurveda and Siddha systems of medicine. Its bark and leaves are adulterated with commercial cinnamon in southern India. Despite its medicinal and commercial importance, the species remains underexplored. The objective of the present work was to screen the chemical composition, in vitro antioxidant, α-amylase and α-glucosidase inhibitory activities of the leaf essential oil of C. wightii collected from different populations. GC-FID and GC-MS analyses of the leaf essential oils from seven accessions enabled the identification of a total of 70 constituents, of which only 16 compounds were present in all samples. Eleven major constituents (> 5%) were identified, of which only linalool and spathulenol were present in all accessions as major constituents. Among seven accessions, essential oil from Parson's valley, Nilgiris exhibited better antioxidant activity with IC50 values of 2.552 ± 0.13 and 3.485 ± 0.09 mg/mL for ABTS and DPPH respectively. The essential oil from Korakundah, Nilgiris showed better hypoglycemic activity with IC50 values of 1.617 ± 0.02 and 1.146 ± 0.02 mg/mL for α-amylase and α-glucosidase inhibitory activities respectively. The leaf essential oils of C. wightii may be used in nutraceutical products focusing diabetes mellitus as the moderate inhibition of the metabolic enzymes has the advantage of slow release of glucose.