Chemical composition and bioactivity studies of the essential oils from two Thymus species from the Pakistani flora

Abstract

The aim of this study was to evaluate the antibacterial, antioxidant, antimalarial and antiproliferative activities of the essential oils of two Pakistani plants, Thymus linearis and Thymus serpyllum of the family Lamiaceae. The GC–MS analyses of the essential oils of T. linearis and T. serpyllum led to the identification of 48 and 35 components, respectively. The major constituents of T. linearis oil were thymol (36.5%), carvacrol (9.50%), thymyl acetate (7.30%), and β-caryophyllene (5.76%), whereas, carvacrol (44.4%), o-cymene (14.0%), α-terpineol (6.47%), α-pinene (6.06%) and β-caryophyllene (5.25%) were the main components of T. serpyllum oil. In the disc diffusion and resazurin microtitre assays, the essential oil of T. linearis showed better antibacterial activity than that of T. serpyllum. Both essential oils were also active, although at relatively high concentrations, against amphicillin-resistant Escherichia coli. In the DPPH assay, the essential oils of T. serpyllum showed more potent antioxidant activity than T. linearis essential oil. Both essential oils exhibited poor anti-haem biocrystallisation activity. In the MTT assay, the anti-proliferative activity of T. linearis essential oil against MCF-7, LNCaP and NIH-3T3 cell lines in terms of IC50 were 80.7, 70.3 and 100.2 μg/ml, respectively, which were notably stronger than T. serpyllum essential oil.