Clin Chim Acta. 2002 Jun; 320(1-2): 11-6.

Effect of five triterpenoid compounds isolated from leaves of Diospyros kaki on stimulus-induced superoxide generation and tyrosyl phosphorylation in human polymorphonuclear leukocytes.

Chen G, Lu H, Wang C, Yamashita K, Manabe M, Xu S, Kodama H.

Department of Phytochemistry, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang 110015, China.

BACKGROUND: The crude drug "kaki-yÃ´" is a traditional medicine used in Japan as a hypotensive drug. METHODS: The effect of five triterpenoid compounds, isolated from leaves of Diospyros kaki on stimulus-induced superoxide generation and phosphorylation of tyrosine residues of protein in human neutrophils was investigated. The five compounds examined were alpha-amyrin (A), uvaol (UV), ursolic acid (UA), 19 alpha-hydroxy ursolic acid (HU) and 19 alpha,24-dihydroxy ursolic acid (DHU). RESULTS: When the cells were preincubated with these compounds, the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) was significantly suppressed in a concentration-dependent manner. These compounds also suppressed the superoxide generation induced by arachidonic acid (AA) in high concentrations. In the case of the superoxide generation induced by phorbol 12-myristate 13-acetate (PMA), UA, HU and DHU suppressed the superoxide generation but A and UV gave no effect. When the cells were incubated with fMLP in UA, HU and DHU, fMLP-induced tyrosyl phosphorylation of 45 kDa proteins of the cells was dose-dependently suppressed in parallel to the suppression of fMLP-induced superoxide generation. CONCLUSIONS: Triterpenoid compounds suppress stimulus-induced superoxide generation and tyrosyl phosphorylation and may have pharmaceutical applications.