The ethanol extract of Moringa oleifera Lam. leaves and its major constituents, crypto-chlorogenic acid, quercetin 3-O-glucoside and kaempferol 3-O-glucoside, were investigated on the respiratory burst of human whole blood and isolated human polymorphonuclear leukocytes (PMNs) using a luminol-based chemiluminescence assay. The chemotactic migration of PMNs was also investigated using the Boyden chamber technique. The ethanol extract demonstrated inhibitory activities on the oxidative burst and the chemotactic migration of PMNs. Quercetin 3-O-glucoside, crypto-chlorogenic acid, and kaempferol 3-O-glucoside, isolated from the extract, expressed relatively strong inhibitory activity on the oxidative burst of PMNs with IC50 values of 4.1, 6.7 and 7.0 microM, respectively, comparable with that of aspirin. They also demonstrated strong inhibition of chemotatic migration of PMNs with IC50 values of 9.5, 15.9 and 18.2 microM, respectively. The results suggest that M. oleifera leaves could modulate the immune response of human phagocytes, linking to its ethnopharmacological use as an anti-inflammatory agent. The immunomodulating activity of the plant was mainly due to its major components.
A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.
Three new triterpenoids; namely 28,28,30-trihydroxylupeol (1); 3,21,21,26-tetrahydroxy-lanostanoic acid (2) and dehydroxybetulinic acid (3) and seven known compounds; i.e., taraxerone (4); taraxerol (5); ethyl palmitate (6); herniarin (7); stigmasterol (8); ursolic acid (9) and acetyl ursolic acid (10) were isolated from the stem of Ficus aurantiaca Griff. The structures of the compounds were established by spectroscopic techniques. The compounds were evaluated for their inhibitory effects on polymorphonuclear leukocyte (PMN) chemotaxis by using the Boyden chamber technique and on human whole blood and neutrophil reactive oxygen species (ROS) production by using a luminol-based chemiluminescence assay. Among the compounds tested, compounds 1-4, 6 and 9 exhibited strong inhibition of PMN migration towards the chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMLP) with IC50 values of 6.8; 2.8; 2.5; 4.1; 3.7 and 3.6 μM, respectively, comparable to that of the positive control ibuprofen (6.7 μM). Compounds 2-4, 6, 7 and 9 exhibited strong inhibition of ROS production of PMNs with IC50 values of 0.9; 0.9; 1.3; 1.1; 0.5 and 0.8 μM, respectively, which were lower than that of aspirin (9.4 μM). The bioactive compounds might be potential lead molecules for the development of new immunomodulatory agents to modulate the innate immune response of phagocytes.