Assessment of Phenolic Content, Antioxidant Properties and Antimicrobial Activity of Flower and Leaf Extracts from Some Hypericum Species Affected by Wild Habitat Altitude

Abstract

In this study, determination of habitat altitude effect on the total phenolic contents, antioxidant and antimicrobial activities of flower and leaf extracts from Hypericum montbretii, H. orientale and H. perforatum species was aimed. The plants were collected randomly from forages (altitudes were ranged from 430 to 1105 m a.s.l.) located in Western Black Sea Region, Turkey. Antioxidant properties of ethanolic extracts were determined with DPPH and ABTS assay and antimicrobial activities of the extracts on Bacillus pumilis NRRL BD-142, B. subtilis NRRL B-209, B. licheniformis NRRL-B-1001, B. cereus NRRL B-3711, Staphylococcus aureus ATCC 33862, Pseudomonas aeruginosa ATCC 27853, Listeria inocua ATCC 33090, L. monocytogenes ATCC 7644 and Escherichia coli ATCC 25922 were examined. Total phenolic contents and antioxidant activities of Hypericum species changed depending on the habitat altitude. The antimicrobial activity of the ethanolic extracts was evaluated by minimal inhibitory concentrations (MIC) method. Flower and leaf extracts exhibited a broad antibacterial spectrum, but they were not effective against Escherichia coli (ATCC 25922). Phenolic contents of all Hypericum species and antimicrobial activity of only H. perforatum extracts were significantly increased by altitude rising, but no positive correlation was detected in antioxidant activity of extracts due to habitat altitude.