This work aimed to investigate the intestinal absorption characteristics of Laportea bulbifera extract in normal and rheumatoid arthritis model rats. The contents of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, kaempferol-3-O-rutinoside, galuteolin, quercetin and isoquercetin in intestinal absorption solution samples were detected by UPLC-MS/MS with 5.0 g·L~(-1) as the absorption concentration. The cumulative absorption(Q) and absorption rate constant(K_a) were calculated, and the absorption characteristics of different components of L. bulbifera in intestinal absorption solution of normal rats and rheumatoid arthritis rats were compared. The results showed that all the eight index components in the extract of L. bulbifera could be absorbed into the intestinal capsule, the cumulative absorption-time curve of each component showed an upward trend without saturation, and the correlation regression coefficient(R~2) was greater than 0.92, which is consistent with the zero-order absorption rate process. It was speculated that the possible absorption mode of each component was passive diffusion. In normal condition, the absorption of ileum was the best(except chlorogenic acid), and in pathological condition, duodenum was the best. The total absorption of 8 components in each intestinal segment of RA rats was better than that of normal rats, which speculated that rheumatoid arthritis may change the specific site of drug absorption. The experimental results showed that rheumatoid arthritis could change the intestinal absorption of the extract of L. bulbifera, and its mechanism needs further study.
Keywords: Laportea bulbifera extract; absorption; everted gut sac model; rheumatoid arthritis rats.