Comparison of Phenolic Compounds Concentrations and Antioxidant Activity of Eight Medicinal Plants Print

Phenolic compounds due to their antioxidant properties are useful for prevention and treatment of meny incurable diseases. The objectives of this study were to determine and compare the flavonoids, flavonols and phenolic contents, as well as Antioxidant Activities (AA) of the extracts of 8 medicinal plants. In this laboratory study, the ethanolic extracts of the plants were prepared and the total flavonoids, flavonols and phenolic compounds, were measured by Folin-Ciocalteau and Aluminium choloride methods. The antioxidant activities were evaluated by β-caroten linoleate model and spectrophotometer at 490 nm. The results showed that total phenolic content of Punica granatum L (flower) (480.67±14.8mg) and Zataria multiflora Boiss (283.43±11.06 mg) were markedly higher than other plants. The lowest content was related to Stachys lavandulifolia Vahl (44.53±8.14 mg). Flavnoid content was variable from 36.56±3.51 mg (Nigella sativa L) to 210.67±21 mg (Tripleurospermum disciforme). Also flavonol contents ranged from 27.66±4.50mg (Nigella sativa L) to 237.33±4.72 mg (Tripleurospermum disciforme). Antioxidant Activity of eight extracts varied considerably and ranged from 44.66±5.50% (Nigella sativa L) to 73±4.58% (Punica granatum L (flower). The results indicated wide differences in the content of effective components and their antioxidant properties of plants. Plants such as pomegranate (flower) extract, chamomile and thyme are rich in phenolic compounds and antioxidant properties, They coud be used as antioxidants in the food industry or in the treatment of various diseases.