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This paper focused on different raw propolis from the harvesting methods which were obtained by scraping and propolis mat respectively,and on the constituents, antioxidant and antitumor activities of different extracts of proplis.1. Phenolic compounds were extracted from two samples both with supercritical CO2 extraction technology and different concentration of ethanol-water assisted by ultrasound. Total phenolics and total flavonoids content in extracts of propolis were estimated by Folin-Ciocalteau method and NaNO2-Al（NO3）3 method respectively. The results indicated that concentration of ethanol had remarkable influence on the yield, the content of total phenolics and total flavonoids of extracts from propolis. The extraction effect was 95% ethanol≈75% ethanol>absolute ethanol>50% ethanol> supercritical CO2 >25% ethanol>water. In the same extraction condition, the method of propolis mat was better than scraping. The maximum yield, the content of total phenolics and total flavonoids of extracts from propolis were 51.03% which was extracted by absolute ethanol, 425.49mg gallic acid/g extract from 25% ethanol, 594.18mg rutin/ g extract from 75% ethanol. Extracts of propolis collected with mat were studied in the following experiments.2. High performance liquid chromatography and electrospray ionization tandem mass spectrometry was used in qualitative and quantitative analysis of phenolic compounds. Based on standards, sixteen phenolic compounds and derivatives were isolated and indentified in extracts of Beijing propolis, including caffeic acid, p-coumaric acid, ferulic acid, 3-hydroxy-4-methoxycinnamicacid, benzoic acid, 3,4-dimethoxy cinnamic acid, cinnamic acid, kaempferol, isorhamnetin, apigenin, rhamnetin, pinocembrin, chrysin, caffeic acid phenethyl ester, galangin, benzyl cinnamate. Caffeic acid, pinocembrin, chrysin and galangin were the main phenolic compounds in Beijing propolis, whose maximum content were 199.20mg/g extract from 25% （w/v） ethanol, 250.05, 148.55, 65.41mg/g extract from 95% （w/v） ethanol, respectively. However, probably because of different drying technology, caffeic acid, p-coumaric acid, ferulic acid, benzoic acid, rhamnetin and benzyl cinnamate were not indentified in commercial refined propolis.3. The antioxidant activities of different extracts of propolis were investigated by chemical and cell-based antioxidant methods. The results showed that there was no direct correlation between two methods. In chemical antioxidant methods including DPPH, ABTS+ free radical scavenging assays and reducing power assay, water extract of propolis （WEP） exhibited the most powerful activities; supercritical CO2 extract of propolis had the weakest antioxidant activities, which was only one sixth of WEP’s. I n cell-based antioxidant methods, 75% （w/v） ethanol extract of propolis had the strongest cellular antioxidant activity （CAA）, whose was fivefold stronger than WEP whose was the weakest. These findings further illustrated that the compositions playing antioxidant role were possibly distinct in two methods, and suggested that absorption of cell should be taken into account in evaluation of antioxidant activities.4. The effects of different extracts of propolis on the proliferation, apoptosis and cell cycle of human hepatocarcinoma cells （HepG2） were systematically investigated. After HepG2 cells were exposed to different extracts for 24h with concentration of 240μg/mL, 75% （w/v） ethanol extract of propolis displayed the strongest growth inhibitory effect and inhibitory rates was 85.19%; water and 25% （w/v） ethanol extract of propolis had weaker growth inhibitory effect than other extracts, whose inhibitory rates were separately 5.04% and 41.47%, and stimulated proliferation of HepG2 cell in low concentration, which were≦160μg/mL and 90μg/mL respectively. The capability of inducing HepG2 cells apoptosis of 95% （w/v） ethanol extract of propolis and commercial refined propolis were relatively stronger （p>0.05）, and which of WEP was the weakest. The ratio of G0/G1 phase cells increased, S phase ratio and G2/M phase ratio decreased after HepG2 cells were exposed to different extracts of propolis at the concentration of 100μg/mL for 24h. In conclusion, propolis exerted antitumor effect by suppressing HepG2 cells proliferation, inducing cells apoptosis and blocking cell cycle.
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