Effect of five triterpenoid compounds isolated from leaves of Diospyros kaki on stimulus-induced superoxide generation and tyrosyl phosphorylation in human polymorphonuclear leukocytes.
BACKGROUND
The crude drug "kaki-yô" 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.
Chen
Guang
G
Department of Phytochemistry, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang 110015, China.
Lu
Huangwei
H
Wang
Chunlei
C
Yamashita
Koichi
K
Manabe
Masanobu
M
Xu
Suixu
S
Kodama
Hiroyuki
H
D000959:Antihypertensive Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D002478:Cells, Cultured; D029788:Diospyros / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000188:drug therapy; D007564:Japan; D008519:Medicine, Traditional; D015394:Molecular Structure; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D018515:Plant Leaves / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry; D013481:Superoxides / Q000378:metabolism*; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology* / Q000627:therapeutic use
D000959:Antihypertensive Agents; D014315:Triterpenes; D013481:Superoxides