Evaluation of antioxidant properties and total phenolic and flavonoids content of Eucalyptus camaldulensis and Pinus sylvestris bark

Plants are a rich sources of phenolic compounds as natural antioxidants. Antioxidants are the main factors in neutralizing free radicals and prevent the spread of diseases and destruction of many foods. These compounds are extractable from the bark of Eucalyptus camaldulensis and Pinus sylvestris trees. The purpose of this study was to evaluate the antioxidant properties and total phenolic and flavonoids of Eucalyptus and pine wood bark. After preparation of the bark، ethanol extracts were extracted using soxhlet extractor. First the amount of total phenol and flavonoids of the extract were measured. Then to evaluate antioxidant properties of the extracts، four methods including Diphenyl Picryl Hydrazyl، reducing power; nitric oxide and metal chelating activity were used. The results showed that total phenol and flavonoid content، in Eucalyptus bark was higher than pine. Test results to trap free radicals of diphenyl Pykryl Hydrazyl showed that 50% inhibitory concentration of ethanol extract of the Eucalypt and Pine bark values as 3. 02 and 15. 77 micrograms per milliliter، respectively. Also، in reducing power test، absorption rate for eucalyptus bark extract was higher than the pine. In nitric oxide trap test، 50% inhibitory concentration in ethanol extract of eucalypt bark was measured as 2. 41 and in pine extract was 22. 75 micrograms per milliliter. Furthermore، the results of Fe2+ chelating ability of ethanol extract of Eucalyptus and pine bark at a concentration of 100 micrograms per milliliter inhibited 37 and 97/18 percent respectively. Ethanol extracts of the eucalypt and pine bark in four case study tests، showed an acceptable antioxidant activity. Thus، these compounds can be regarded as good sources ofnatural antioxidants.