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Some commercial extracts of propolis obtained with different solvents were tested to evaluate their antibacterial and antifungal activity. All propolis preparations exhibited antimicrobial activity, particularly against Gram‐positive bacteria, yeasts and dermatophytes with zones of inhibition ranging from 3 to 30 mm. Against yeasts and dermatophytes, oil, ethanol and propylene glycol solutions showed an inhibition for more 2 weeks, while the glycerine solution maintained inhibition only for some days. The results indicate that the solvent employed for the extraction may enhance the potency of the antimicrobial activity of propolis. Consistency in the properties and characteristics of propolis were related to the formulation of extraction procedures.

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We have previously shown that unsaturated phosphatidylserines inhibit mitogen‐induced T cell activation. We now report that the inhibitory action requires a protein present in bovine and human serum. Partial purification and phospholipase assay show that this protein has phospholipase A activity on phosphatidylserine but not phosphatidylethanolamine, phosphatidylcholine and phosphatidylinositol. In short incubations (1–3 h) 2‐acyl lysophosphatidylserine is produced but in longer incubations the cis‐unsaturated fatty acid is also released. Experiments on peripheral blood mononuclear cells indicate that the unsaturated fatty acid becomes the main responsible for the PS‐induced inhibition and that 2‐acyl lysophosphatidylserine enhances the inhibitory effect of fatty acid.