Inhibition of Neutrophil Chemotaxis and Superoxide anion Generation by a Pure Compound from Artocarpus lakoocha Roxb.

Abstract

            Artocarpus lakoocha Roxb., belonging to the family Moraceae and called Ma-Haad in Thailand, has been used in traditional folk medicine for the treatment of various diseases.  A pure compound from A. lakoocha (Compound A) was demonstrated to possess strong anti-inflammatory activity in the EPP-induced mouse ear edema model.  Neutrophil has been known to play an important role in acute inflammation.  The aims of this study were to investigate the anti-inflamatory effects of Compound A in vitro based on human neutrophil chemotaxis and superoxide anion generation.  Neutrophils were isolated from the peripheral blood of healthy donors by discontinuous Percoll density gradient centrifugation and viability was assessed by trypan blue exclusion.  The cytotoxic effects of Compound A were primarily investigated by XTT assay.  Its direct free-radical scavenging activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay.  The effects of Compound A on fMLP-induced human neutrophil chemotaxis and superoxide anion generation (SAG) were determined spectrophotometrically.  The results showed that fMLP-induced human neutrophil chemotaxis and SAG were inhibited in a concentration-dependent manner by Compound A.  In addition, compound A exhibited strong radical-scavenging activity when compared with trolox.  Slight cytotoxic effects of compound A were observed at the concentrations used  These findings suggest that inhibition of fMLP-induced chemotaxis and superoxide anion generation of activated human neutrophils might account, at least in part, for the anti-inflammatory activity of Compound A.