Evaluation of propolis (II) : Effects of Brazilian and Chinese propolis on histamine release from rat peritoneal mast cells induced by compound 48/80 and concanavalin A

To establish a biological method for evaluating propolis and to reveal their anti-allergic action, the effects of the ethanol and water extracts (EA-ET and WA-WT, respectively) from Brazilian, Chinese and Japanese propolis on the histamine release induced by compound 48/80 and concanavalin A (Con A) were investigated. The relation between the inhibitory activities of these extracts on the histamine release and their E1%1cm values were also examined. As a result, the following was found : 1) 0.003-0.01% ethanol and 0.03-0.1% water extracts inhibited the histamine release induced by compound 48/80 and Con A, and the inhibitory potencies of the former extracts were more than 10 times stronger than those of the latter extracts, making it clear that both the ethanol and water extracts possesse an anti-allergic action; 2) most of the ethanol and water extracts responded to the histamine release induced by both the histamine releasers in a concentration-dependent manner; 3) the inhibitory activities of 0.003% EM from Hebei Province, EP from Sichuan Province, EQ from Zhejiang Province and ER from Anhui Province in China were weaker than those of 0.01% corresponding extracts, whereas 0.001% ED-EH from Brazilian propolis, EM, EN from Henan Province in China and EP-ER promoted the Con A-induced histamine release of more than 10%, suggesting that such extracts must be carefully given to humans; 4) the inhibitory potencies of only 0.03-0.1% water extracts from Chimese propolis on the Con A-induced histamine release related excellently with their E1%1cm values; 5) from the results of the relation between the inhibitory potencies of the propolis extracts and their E1%1cm values, it was suggested that an unknown compound, being a poorly water-soluble compound which is a non-flavonoid, with an anti-allergic action is contained in propolis; 6) to precisely evaluate the anti-allergic action of the propolis, the biological method, which measures the inhibitory activities of the propolis extracts on histamine release, was markedly superior to the physicochemical method.