Antibacterial, antioxidant and hypoglycaemic effects of Thymus capitatus (L.) Hoffmanns. et Link leaves' fractions

Abstract

The aim of this study was to examine the bioactivity of the methanol fraction (MF) and n-hexane fraction (HF) of Thymus capitatus leaves in relation to their constituents analysed by gas chromatography and gas chromatography-mass spectrometry. The effects of T. capitatus on the growth of pathogenic bacteria associated with respiratory diseases (13 gram-positive and 4 gram-negative) were determined using a microdilution method. The MF was particularly effective on Streptococcus pneumoniae and Moraxella catarrhalis. The antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing antioxidant power and β-carotene bleaching assays. A strong activity using β-carotene bleaching test was observed with the MF (IC₅₀ of 0.7 μg/mL after 30 min of incubation). In the hypoglycaemic test, a selective α-amylase inhibitory activity was detected with the HF begging the most active (IC₅₀ of 422.5 μg/mL). T. capitatus may represent a source of natural bioactive compounds.

• Antibacterial properties
• antioxidant
• GC-MS analysis
• hypoglycaemic
• Thymus capitatus

Acknowledgements

This work is dedicated to the memory of Prof. Liliana Iauk.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.