title: Ochnaflavone, naturally occurring biflavonoid, inhibits phospholipase A2 dependent phosphatidylethanolamine degradation in a CCl4-induced rat liver microsome.
abstract: This study investigated the protective effects of a group IIA secretory phospholipase A2 (sPLA2-IIA) inhibitor, ochnaflavone, on the progression of carbon tetrachloride (CCl4)-induced acute liver injury in rat liver microsomes in vitro. When rat liver was incubated at 37 degrees C in the presence of CCl4, the level of phosphatidylethanolamine (PE) degradation increased markedly compared with the control. The rat 14 kDa platelet PLA2 antibody, R377, suppressed the degradation of PE. Pretreating the microsome with ochnaflavone (2-16 microM) reduced the level of PE degradation in a dose dependent manner. In addition, p-bromophenacy bromide (p-BPB), which is a PLA2 inhibitor, also inhibited PE degradation. However, the inhibitory activity was weaker than that of ochnaflavone. Further investigation showed that ochnaflavone not only inhibited the purified rat platelet sPLA2 activity in a dose dependent manner with an IC50 value of 3.45 microM, when arachidonyl PE was used as a substrate, but also inhibited lipid peroxidation in a dose dependent manner with an IC50 value of 7.16 microM. This result suggests that ochnaflavone prevents the progression of CCl4-induced PE hydrolysis by inhibiting the endogenous sPLA2 activity.
authors.affiliation: College of Pharmacy, Yeungnam University, Gyeongsan, Korea.
authors.forename: Tae Chul
authors.initials: TC
authors.lastname: Moon
authors.forename: Hwa Shin
authors.initials: HS
authors.lastname: Hwang
authors.forename: Zhejiu
authors.initials: Z
authors.lastname: Quan
authors.forename: Kun Ho
authors.initials: KH
authors.lastname: Son
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
authors.forename: Hyun Pyo
authors.initials: HP
authors.lastname: Kim
authors.forename: Sam Sik
authors.initials: SS
authors.lastname: Kang
authors.forename: Jong Keun
authors.initials: JK
authors.lastname: Son
authors.forename: Hyeun Wook
authors.initials: HW
authors.lastname: Chang
mesh_terms: D000818:Animals; D002251:Carbon Tetrachloride / Q000633:toxicity*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D006868:Hydrolysis; D008862:Microsomes, Liver / Q000187:drug effects* / Q000201:enzymology; D010714:Phosphatidylethanolamines / Q000378:metabolism*; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D051381:Rats
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D010714:Phosphatidylethanolamines; C483858:phosphatidylethanolamine; C090940:ochnaflavone; D002251:Carbon Tetrachloride; D010741:Phospholipases A; D054467:Phospholipases A2