In vitro gastrointestinal digestion of a bisdemethoxycurcumin-rich Curcuma longa extract and its oral bioavailability in rats

Abstract

Abstract Background Nonetheless curcumin has potential health benefits, its low bioavailability limits the application of conventional turmeric extract with curcumin as major curcuminoid. This is a comparative study to assess the stability, bioaccessibility and biological activity of BDMC in standardized C. longa extract (REVERC3) relative to curcumin in regular turmeric extract (RTE). Here we report the preparation of a standardized Curcuma longa extract (REVERC3™) standardized to contain 75 ± 5 w/w % bisdemethoxycurcumin (BDMC), 1.2 ± 0.8 w/w % curcumin and 10 ± 5 w/w % demethoxycurcumin (DMC). The turmeric extracts were subjected to in vitro gastrointestinal digestion and the curcuminoids in undigested and digested samples were analyzed using HPLC to determine the bioaccessibility. Further, the undigested and digested samples were evaluated for lipase inhibition and antioxidant activities. Male Wistar rats were administered with single dose (1000 mg/kg) of standardized C. longa extract and RTE to determine the plasma concentration of BDMC and curcumin respectively at different time points using LCMS/MS. Results The bioaccessibility of BDMC was significantly higher than curcumin (p < 0.05). BDMC was found superior to curcumin having significant lipase inhibitory effect (p < 0.01), ABTS radical scavenging (p < 0.05), and nitric oxide scavenging activities (p < 0.01). Interestingly, the relative bioavailability of BDMC in standardized C. longa extract was 18.76 compared to curcumin. The Cmax of BDMC was 4.4-fold higher than curcumin. Conclusion BDMC is reported to have higher bioaccessibility and bioavailability than curcumin. Our findings rationalize use of BDMC-enriched standardized C. longa extract for improved physiological benefits counteracting the regular turmeric extract with less bioavailable curcumin as major curcuminoid.