Antioxidant Activity and Constituents of Propolis Collected in Various Areas of Korea

Abstract

Propolis is a resinous substance collected by honeybees from various plant sources. The composition of propolis depends on time, vegetation, and the area of collection. This study examined the antioxidant activity of propolis from various areas of Korea: Chilgok, Cheongju, Geochang, Muju, Pocheon, and Sangju. Ethanol extracts of propolis (EEP) were prepared and evaluated for their antioxidant activity by beta-carotene bleaching, 1,1-diphenyl-2-picrylhydrazyl free radical scavenging, and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assays. Furthermore, the major constituents in EEP were identified by high-performance liquid chromatography analysis with a photodiode array and mass spectrometric detection, and each component was quantitatively analyzed. EEP from Cheongju and Muju had relatively strong antioxidant activity accompanied by high total polyphenol contents. Propolis from Cheongju contained large amounts of antioxidative compounds, such as caffeic acid, kaempferol, and phenethyl caffeate. On the other hand, propolis from Pocheon had compounds not seen in propolis from other areas.

Fingerprinting of propolis by easy ambient sonic-spray ionization mass spectrometry

“…Although the HPLC-MS chromatograms of propolis are useful for the quantification of individual components in propolis, the qualitative characterization of samples is just as effectively carried out using MS fingerprinting techniques. For instance, the grouping of Korean propolis samples by EASI-MS in our results is the same as by HPLC-MS [8]. The EASI-MS fingerprints of propolis samples are qualitatively similar to those obtained by direct insertion ESI-MS in previous studies [17][18][19] but can be obtained more quickly, for dozens of samples on a roll, without any pre-separation or sample preparation procedure.…”

“…The composition of one of these samples (K43, from Pocheon) was reported to be different from the other samples of Korean propolis [8]. This sample had a much lower concentration of flavonoids and polyphenols and intense but unidentified ions corresponding to less polar substances observed at the end of the HPLC analysis.…”

“…The characteristic ions of this group again correspond to Populus flavonoids (m/z 269: apigenin/galangin; m/z 271: pinobanksin; m/z 313: pinobanksin acetate and m/z 283: caffeic acid phenethyl ester). The major components of the Korean samples placed in this group (K39-Geochang, K41-Muju and K38-Sangju) were identified by Ahn et al [8] using HPLC. These flavonoids are also quite common in propolis from the South of Brazil and Central Chile [6] and their ions have been observed in ESI-MS of samples from the USA and Europe [19].…”

“…Some studies have reported on the composition of A. mellifera propolis from other regions of the world such as New Zealand [7] and Korea [8], including flavonoids as important constituents of propolis from these regions. For the majority of Asian or African countries, however, the composition and plant origins of propolis samples are only recently being studied [9][10][11].…”

Predictive mathematical modeling for EC50 calculation of antioxidant activity and antibacterial ability of Thai bee products

“…The total phenol content (TPC) of the bee product samples was determined using the Folin-Ciocalteau method as described by Ahn et al (2004) with slight modifications. The sample (0.3 mL) was put in a test tube, and 3 mL of distilled water, 0.25 mL of 2.0 N Folin-Ciocalteu reagent and 2.5 mL of 7% (w/v) sodium carbonate were added.…”