Evaluation of antioxidant activity and flavonoid composition in differently preserved bee products

Abstract

Antioxidant potential and composition of phenolic compounds were studied in pure bee products (beebread - BB, bee pollen - BP) and in their mixtures with honey and vegetable oils [sea buckthorn (SBO), flax seed (FSO), royal jelly (RJ)], and the alga Spirulina (SA). The values of total phenolic content (TPC) found in the raw weight (RW) of material of BP, BB, SA, and RJ were 23.3, 21.2, 15.4, and 10.7 GAE mg/g, respectively. The methanolic extract of pure BP possessed higher ABTS+scavenging capacity (5.37-6.47 TE mg/g RW) than BB (4.86-5.70 TE mg/g RW). The values of oxygen radical absorbance capacities (ORAC) of methanolic extracts of BB and BP were 626.30 and 894.04 TE mg/g RW, respectively. An analysis of flavonoids in the products by the ultra performance liquid chromatography showed that pure BP possesses a broader spectrum of compounds than pure BB. Three forms of glycosides were identified in BP: quercetin 3-O-sophoroside, quercetin dihexoside and isorhamnetin 3-glucoside. Rhamnetin and isorhamnetin as well as their glycosides and kaempferol 3-O-α-l-(2"-E-p-coumaroyl-3"-Z-p-coumaroyl)-rhamnoside were determined in the samples of pollen mixed with honey (BPH).