Antioxidant activity, phenol and flavonoid contents of 13 citrus species peels and tissues.

Methanolic extracts of 13 commercially available citrus spp., peels and tissues growing in Iran were investigated for their antioxidant activity by DPPH method. IC50 for antioxidant activity ranged from 0.6-3.8 mg ml(-1). Total phenolic content of the citrus spp. samples (based on folin Ciocalteu method) varied from 66.5 to 396.8 mg gallic acid equivalent/g of extract and flavonoids content (based on colorimetric AlCl3 method) varied from 0.3 to 31.1 mg quercetin equivalent/g of extract. There were no correlation between the total phenolic and/or flavonoids contents and antioxidant activity in tissues and/or peels.