Bioactive Content and in vitro Antioxidant and Enzyme-Inhibitory Potential of Leaf and Fruits of Parsnip (Pastinaca sativa L. subsp. Urens)

Parsnip (Pastinaca sativa L. subsp. urens) is one of the species of Pastinaca genus. This plant has been traditionally used worldwide for the treatment of various diseases and cultivated for its nutritional values. The aim of this study was to determine the antimicrobial and enzyme-inhibitory potentials of the fruits and leaves of parsnips as well as their bioactive properties such as their antioxidant activities, total phenolic and flavonoid contents in their hexane and ethanol extracts. The total phenolic and flavonoid contents were determined using Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activities of extracts were determined by three methods of DPPH and ABTS radical scavenging activities and iron-chelating ability. In the leaves, the highest total phenolic content (60.94 mg GAE/g extract) was found in ethanol extracts while the highest total flavonoid content (21.47 mg RuE/g extract) was determined in hexane extracts. Ethanol extracts of leaves showed the highest radical scavenging activities in both assays of DPPH and ABTS with the IC50 values of 1039±1.35 and 150.7±0.81 µg/mL, respectively. Growth inhibition zone diameters (mm) of PSFE, PSLE, PSFH, PSLH (2 mg/mL) against reference microorganisms were -/-/15/15, -/-/15/14, 10/10/22/15, -/-/15/14 and MIC values -20>/20>/20>/20>, 20>/20>/20>/2.5, 0.625/10/-/-, 20>/20>/20>/20> mg/mL for Staphylococcus aureus ATCC6538, Micrococcus luteus ATCC9341, Bacillus subtilis ATCC6633, Candida albicans ATCC14053, respectively. Antimicrobial activity was not determined against other reference microorganisms.