Anti-diarrheal constituents of Alpinia oxyphylla.

Isolation, screening and in vivo assays have been used for evaluating anti-diarrhea bioactive of Alpinia oxyphylla. Preliminary experimental results showed that 95% ethanol extract and 90% ethanol elution significantly extended the onset time of diarrhea and reduced the wet feces proportion, however 50% ethanol election had no effect on diarrhea. Chemical analysis results displayed that Nootkatone, Tectochrysin and yakuchinone A may be bioactive ingredients for curing diarrhea. Duodenum in vitro experiment showed that Tectochrysin 50, 100 μM reduces carbachol-induced contraction, while yakuchinone A and Nootkatone had no effect. Bioinformatic computational method as molecular docking has been complementary to experimentally work to explore the potential mechanism. The study of pathogenesis of diarrhea in humans and animal models suggested that Na(+)/H(+) exchanger3 (NHE3) and aquaporin4 (AQP4) are causative agents of diarrhea. The analysis was done on the basis of scoring and binding ability and the docking analysis showed that Tectochrysin has maximum potential against NHE3 (PDB ID: 2OCS) and AQP4 (PDB ID: 3GD8). Tectochrysin indicated minimum energy score and the highest number of interactions with active site residues. These results suggested that A. oxyphylla might exhibit its anti-diarrhea effect partially by affecting the proteins of NHE3 and AQP4 with its active ingredient Tectochrysin.