Arbutin content and antioxidant activity of some Ericaceae species.

Quantitative analyses and investigation of antioxidant activity of herb and dry ethanolic extracts of five species from Ericaceae family (Arbutus unedo L., Bruckentalia spiculifolia Rchb., Calluna vulgaris Salisb., Erica arborea L. and Erica carnea L.) were performed. Total polyphenols, tannins and flavonoids were determined spectrophotometrically and arbutin content was measured both spectrophotometrically and by HPLC coupled with DAD detection. Antioxidative properites of the ethanolic extracts were tested by means of FRAP (total antioxidant capacity), lipid peroxidation and DPPH free radical scavenging activity. A significant amount of arbutin was detected only in Arbutus unedo. All samples investigated showed excellent antioxidant activity. The best inhibition of lipid peroxidation has been shown by Bruckentalia spiculifolia herb extract (62.5 microg/ml; more than 95%), which contained the highest amount of flavonoids (11.79%). The highest scavenging activity was obtained with leave extract of Arbutus unedo (IC50 = 7.14 microg/ml). The leaves of A. unedo contained a small amount of flavonoids but high content of non-tannins polyphenols.