Metabolic study is an important approach to understand the fate of a drug. Many successful in vivo and in vitro works have been carried out on occidental drugs which contain only one pure compound. Compared to the in vitro metabolic study on individual ingredient, the metabolism of the whole extracts of herbs is supposed to reflect more reality of the fate of TCMs. Recently, researchers in Chengdu Institute of Biology used an magnetic metabolic bioreactor to investigate the metabolism of the whole extract of a traditional Chinese medicinal plant, Rhizoma coptidis.

Firstly, researchers immobilized rat liver microsomes on SiO₂-coated Fe₃O₄ magnetic nanoparticles to develop a highly active and recoverable nanoparticle bioreactor (LMMNPs). Incubation of berberine, a major active ingredient of R. Coptidis with LMMNPs for 20 min produced two metabolites, demethyleneberberine and thalifendine at high levels. By comparing the time courses of thalifendine formation, it was found that LMMNPs had a higher biological activity than free liver microsomes in metabolizing berberine. At the same time, LMMNPs’ activity remained almost unchanged after six consecutive usages in the incubation tests.

Secondly, using this bioreactor, they investigate the In vitro metabolism of Rhizoma Coptidis extract. The same two metabolites of berberine demethyleneberberine and thalifendine, were detected. It was interestingly found that demethyleneberberine was the common metabolite of 5 protoberberine-type alkaloids present in R. Coptidis extract, including palmatine, jatrorrhizine, columbanine, epiberberine, and berberine.

This work developed a highly active magnetic bioreactor for metabolizing TCMs. They were easily recovered from the incubation solution magnetic separation, resulting in a protein free incubation solution for its convenient chemical analysis, and were reusable to reduce study cost. Coupled with UPLC-UV-MS, the method established in this work has been proven to be a powerful tool for In vitro metabolic study of the whole extract of TCMs. This research has been published in Anal Bioanal Chem.