Abstract

Aqueous and hydro-alcoholic extracts of Achillea biebersteinii Afan. (Asteraceae) grown in Jordan were screened for their antioxidant, antibacterial and antiplatelet efficacy. Total phenols and flavonoids were determined colorimetrically. The radical scavenging activities were evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activity assays. Antimicrobial activities were determined by the disc-diffusion method, and the minimum inhibition concentration and the minimum bactericidal concentration tests. Gram positive bacteria presented sensitivity to the hydro-alcoholic extract in the disk diffusion test. No significant activity was observed against Gram negative bacteria and Candida albicans. Hydro-alcoholicextract had a bactericidal activity against Streptococcus pneumoniae, Bacillus cereus, Enterococcus faecalis and Klebsiella pneumoniae rather than inhibitory effect. In vitroantiplatelet activity was determined with human whole blood using an electrical impedance method. At concentrations (50, 100, and 200 μg/ml), the extracts showed a non-dose dependent enhancement of platelet aggregation induced by adenosine diphosphate (ADP) (51.82, 52.73 and 51.82%, respectively) and collagen (0.00, 11.76 and 23.53%, respectively). High performance liquid chromatography-mass spectrometry (HPLC-MS) analysis resulted in the identification of 8 phenolic compounds; quercetin 3-β-D-glucoside was the main component.

Key words: Achillea biebersteinii, Asteraceae, antioxidant activity, antibacterial activity, antiplatelet activity, Jordan.