Acta Pharm. 50 (2000) 29-37
Flavonoids of Hyperici herba (Hypericum perforatum L., Hypericaceae) collected in southwest Macedonia, were examined. The total flavonoid content determined spectrometrically (with AlCl3) was found to be 1.9%. The total flavonoid and total aglycone content varied in aqueous, aqueous-ethanolic and ethanolic extracts prepared from the same plant material. The highest value of total flavonoids (1.32 mg mL-1) was found in extracts obtained with 70% ethanol, whereas for total aglycones 50% ethanol was found to be the most effective extraction solvent giving 0.84 mg mL-1 aglycones. The content of total and aglycone quercetin was determined using HPLC. Its content in the plant material was found to be 1.3%. Analogously to flavanoids the highest value for total quercetin (0.68 mg mL-1 ) was also found in extracts prepared with 70% ethanol, and for aglycone 50% ethanol was most favorable and yielded 0.24 mg mL-1 quercetin. In olive oil extracts of Hyperici herba, highest yield of total flavonoids was obtained after three hours of digestion at 100 °C. Total flavonoids content in these oil extracts was 13.0 mg per 100 g.
Keywords: Hypericum perforatum L. (Hypericaceae), extracts, flavonoids, quercetin, spectrometry, HPLC