Identification and distribution of four metabolites of geniposide in rats with adjuvant arthritis.

Geniposide (GE), also called Jasminoidin, is the major active ingredient of Gardenia jasminoides Ellis (GJ) fruit, which has long been used in traditional Chinese medicine (TCM). Growing evidences suggested that GE has a great potentiality for treating rheumatoid arthritis (RA). However, GE is rapidly metabolized, and we know little about its availability or metabolites in tissues. To elucidate the distribution of GE and its metabolites in tissues, three groups of adjuvant arthritis (AA) rats were given GE (33, 66 and 120 mg/kg) from days 18 to 24, and the biotransformation of GE in plasma, liver, spleen, synovium, urine and mesenteric lymph node (MLN) of rats was investigated by a novel approach named Information-Dependent Acquisition (IDA)-Mediated LC-MS/MS method. As a result, GE and its four major metabolites were detected as follows: GE, G1, G2 in plasma; GE, G2 in MLNs; only GE in liver and synovium; GE, G2, G3 and G4 in spleen; and GE, G1, G2 and G4 in urine. In total four metabolites (G1-G4) involved in the in vivo metabolism processes were identified. The results of this work have demonstrated the IDA-Mediated LC-MS/MS could screen rapidly and reliably the characterization of metabolites from iridoid compounds.