In vitro immunomodulatory effects of Astragalus verus Olivier. (black milkvetch): an immunological tapestry in Kurdish ethnomedicine.

Astragalus verus Olivier., Fabaceae, has been used as an immunopromoting remedy in Kurdish ethnomedicine. Here, phagocytic (nitroblue tetrazolium (NBT) dye reduction and lysosomal enzyme activity of mouse splenocyte), (co)mitogenic (mouse splenocyte reduction of methyl thiazolyl tetrazolium (MTT)), and antioxidative (nitrite-induced methemoglobin formation) activities of A. verus extracts and chemical compositions of their essential oils (gas chromatography-mass spectrometry) were investigated. All aqueous (AQ), acetone (AC), and methanol (ME) extracts of aerial parts and root polysaccharide extract (PS) enhanced phagocytic activity compared with the control. The phagocytic activities assayed by lysosomal enzyme activity were in agreement with the values obtained by NBT reduction test and followed the order AQ > PS > AC > ME. All A. verus extracts showed enhanced mitogenic activities compared with the control; however, the AQ extract at 200 μg/mL showed maximum mitogenic activity by 311% compared with the control. The stimulation index values obtained by lipopolysaccharide comitogenic activity were roughly in agreement with the values obtained by concanavalin A comitogenic activity and followed the order AQ > PS > AC > ME. The AQ extract showed profound antioxidant activity while other extracts did not show an acceptable antioxidant activity. The main components isolated from the essential oil of A. verus were thymol in AQ, n-hexadecanoic acid, 1,2-benzenedicarboxylic acid, diisooctyl ester, and phytol in both ME and AC and tetradecane, pentadecane, hexadecane, and phenol,2,4-bis(1,1-dimethylethyl) in PS. The results clearly showed that A. verus could be employed as an immunopromoting remedy; however, more advanced researches are requested to develop a promised pharmaceutical drug from A. verus in the future. [ABSTRACT FROM AUTHOR]