ABSTRACT
<p><b>OBJECTIVE</b>To study the stability of costunolide (COS) and dehydrocostus lactone (DEH) of Vladimiriae Radix before and after being roasted in artificial gastric juice, artificial intestinal juice and isolated rat gastric, intestinal or colonic incubation juice.</p><p><b>METHOD</b>The HPLC method was used for the determination of the mass concentration of COS and DEH Vladimiriae Radix before and after being roasted artificial gastric juice, artificial intestinal juice and isolated rat gastric, intestinal or colonic incubation juice. The samples were incubated with isolated rat stomach, small intestine; colon was used to study physical adsorption, absorption or degradation parameters.</p><p><b>RESULT</b>COS of Vladimiriae Radix before or after being roasted was unstable in artificial gastric juice, with the average degradation constants as 0.758 0 and 0.531 1. Having been roasted, it showed an increasing stability with a significant difference (P < 0.01). Both of COS and DEH of Vladimiriae Radix before or after being roasted showed high adsorption, uptake or degradation (2 h), and it had significant difference between different parts.</p><p><b>CONCLUSION</b>COS was unstable in artificial gastric juice (unprocessed Vladimiriae Radix has a higher degradation rate). Isolated rat stomach, small intestine, colon can adsorb, take, degrade COS and DEH of Vladimiriae Radix before or after roasting process obviously and differently. It provides basis for studies on the absorption mechanisms of effective ingredients of Vladimiriae Radix before and after being roasted.</p>