US EPA

1048190 

Journal Article 

Inhibitory effect of a bitter melon extract on the P-glycoprotein activity in intestinal Caco-2 cells 

Konishi, T; Satsu, H; Hatsugai, Y; Aizawa, K; Inakuma, T; Nagata, S; Sakuda, SH; Nagasawa, H; Shimizu, M 

2004 

Yes 

British Journal of Pharmacology
ISSN: 0007-1188
EISSN: 1476-5381 

143 

3 

379-387 

English 

15351776 

10.1038/sj.bjp.0705804 

WOS:000224545100006 

Extracts of bitter melon, soybean, dokudami and welsh onion by 40% methanol increased the accumulation of rhodamine-123 by Caco-2 cells, suggesting that these extracts inhibited P-glycoprotein (P-gp). The extract of bitter melon was separated in a tC18 cartridge column and the eluate from 80% acetonitrile most markedly increased the [(3)H]-daunomycin accumulation by Caco-2 cells. The inhibitory compounds in the bitter melon fraction were isolated by HPLC with Pegasil C4 and Pegasil ODS columns. The HPLC fraction having the highest activity was analyzed by (1)H-NMR and FAB-MS, and the active compound was identified as 1-monopalmitin. The inhibitory activities of 1-monopalmitin and its related compounds suggested that the inhibition of P-gp activity was not dependent on the degree of unsaturation of fatty acid in the monoglyceride, but on the chain length. It was also suggested that the monoglyceride structure played an important role in the inhibition of P-gp activity. Monoglycerides could therefore alter the pharmacokinetics of drugs by inhibiting the P-gp-mediated efflux. 

P-gp; bitter melon; Caco-2; daunomycin accumulation; 1-monopalmitin