Chemical Compositions And Bioactivities Of Water Extract Of Propolis From Different Areas Of China

Propolis is a resinous, strongly adhesive natural substance, collected by honeybees (Apis mellifera L.) from buds and leaves of trees and plants. Nowadays, more than 200 different constituents, including benzoic acids, flavonoids, and cinnamic acid derivatives have been isolated and identified from propolis. Sevaral biological activities of propolis such as anti-inflammatory, antibacterial, antiviral, immunomodulatory, and antioxidant effects have been studied. In this paper, the chemical constituents, antioxidant activities and bacteriostatic activity of water extract of propolis (WEP) from different areas of China were studied and compared, mathematical were established. The results are as followings.1. WEPs of China were obtained by modified water extract method, and the average yield of WEPs was 6.0±1.6%. Spectrophotography was used to determine the physico-chemical properties and the main chemical constituents of WEP. Total phenol and soluble sugar were the main chemical constituents in WEP. The physico-chemical properties among WEPs were different significantly. The WEP which was light in color contained more compositions, such as yellow prpolis. WEP from tropic and subtropical zones had lower chemical compositions than WEP from other areas apparently, but the latter had no remarkable difference among each other.2. The RP-HPLC method that could analysis 23 kinds of polyphenolic components at the same time was developed. The separation was performed on ZORBAX Eclipse XDB C18 column (4.6 mm×150 mm×5μm) by gradient elution. The mobile phase consisted of ethanol with 0.1% formic acid at the flow rate of 1.0 ml/min. The detection wavelengths are 256 nm and 280 nm. The injection volume was 20μL, and the column temperature was maintained at 35℃. The standards mixtures, which were divided into two groups, and WEPs could be separated well under 256 nm and 280 nm. The calibration curves of each sample showed good linearity. For each sample, relative standard deviation (RSD) of precision was less than 2.11%, RSD of repeatability was less than 4.33%, and recoveries were between 93.29% and 106.61%.All WEP were detected by this method. Different samples have different combination and content of standards. Epicatechin, p-coumaric,morin, 3,4-dimethoxycinnamic acid, naringenin, ferulic acid, cinnamic acid, pinocembrin and chrysin were the main compounds of WEP of China. WEP from YN-2 had special print which different from other areas.3. Prussian blue spectrophotometry was used to examine the total antioxidant activity, and DPPH was used to determine the free radical scavenging ability of WEP. It was showen that the most WEP had strong antioxidant activity and could be natural antioxidant. The yellow WEP had stronger total antioxidant activity and free radical scavenging ability. WEP from tropic and subtropical zone had apparently lower total antioxidant activity and free radical scavenging ability than WEP from other areas which had no marked difference among each other. This is agree with the chemical compositions. Since the relationship between the antioxidant activity and total phenol and flavone-flavonol was significant, the antioxidant activity of WEP was due to the aboved composition. E1cm/1％could be used as a quality index to estimate the quality of WEP easily and quickly.4. The antimicrobial activity on five selected microbes of WEP was assayed by the agar well diffusion method. The results suggested that WEP had antimicrobial activity. The relative order of sensitivity of the five microbes from the most to least were:Staphyloccocus aureus>Escherichia coli>Clostridium perfringens>Mucor racemosus> Proteusbacillus vulgaris WEP from YN-2 showed no abserved antimicrobial activity. As reported in EEP, the Gram positive bacteria tested by WEP were highly sensitive to Gram negative bacteria.5. There was significant difference with regards to the seasonal effect on the chemical constituent and antioxidant activity of WEP from tropic and temperate zone of China. WEP from SD and Hu had similar chemical constituents, and higher than WEP from tropic zone. WEP from tropic zone had weak antioxidant activity.6. Model based on E1cm/1％, total phenol, flavone-flavonol and antioxidant activities could reflect the relation between compositions and antioxidant activities of WEP. Total antioxidant activity model is Y total antioxidant activity=0.003XE1cm/1％+0.003Xtotal phenol+0.092Xflavone-flavonol-0.281, and free radical scavenging ability of DPPH model is YDPPH=0.002XE1cm/1％+0.003Xtolal phenol+0.068X tlavone-flavonol-0.011. WEP contained many chemical constituents such as total phenol, total flavonoids and so on. WEP also had good antioxidant activities and bacteriostatic activity.The bioactivities associated with interspecific difference and chemical composition of total phenol and flavone-flavonol. Significant difference with regards to the seasonal effect on the chemical constituent and antioxidant activity were gound in WEP of China. There was feasibility and better perspective in exploition of WEP in our country.