PHYTOCHEMICAL CONSTITUENTS, ANTIOXIDANT, ANTIBACTERIAL AND ENZYME INHIBITION ACTIVITIES OF ESSENTIAL OIL FROM THE AERIAL PART OF Achillea tomentosa L. GROWN IN JORDAN

Abstract

This investigation aimed to evaluate the phytochemical constiuents, antioxidant, antibacterial and α-glucosidase inhibitory activities of A. tomentosa essential oil. The essential oil extracted using steam distillation method possessed antibacterial activity for all tested bacteria. Comparing to cefaclor the percentage of relative inhibition zone diameter (RIZD) was 100.30 ± 4.73 % for Staphylococcus aureus and ranged between 79.67 ± 3.79 % and 84.33 ± 4.16 % for other bacteria. The essential oil showed considerable antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric reducing antioxidant power (FRAP) assay and metal chelating methods, the EC50 of the essential oil were 72.06 ± 3.99, 54.69 ± 4.69 and 50.39 ± 2.86 µg/ml respectively. Comparing to EC50 7.34 ± 2.43, 10.87 ± 3.34 and 14.50 ± 3.46 µg/ml for positive controls (Trolox, EDTA and Quercetin respectively). The essential oil also possessed concentration dependent α-glucosidase inhibitory activity with EC50 149.20 ± 7.63 µg/ml comparing to acarabose EC50 14.50 ± 3.46 µg/ml. Forty compounds were identified depending in retention index (RI) and mass spectra (MS) that form 96.31 %of the essential oil composition. The result showed that the ratio of the identified compounds range between 0.11 % and 23.72 %, 3-Carene (23.72 %), Limonene (12.19 %) and α-Terpinyl acetate (10.22%) were found to be the major components of the essential oil. m-Cymene (7.11 %) and Di-n-octyl phthalate (4.50 %) present in moderate quantities. The phytochmical analyzes showed that the identified compound quantitatively and qualitatively differ from the previous study that investigate the composition of A.tomentosa L. essential oil.