Effect of Carbonized Herba schizonepetae on the Bioavailability of Eight Active Components from Pulsatillae Decoction in its Particular Adsorption and Release Performance

Background: Carbonized herbal medicine has been used clinically for centuries in China; however, its influence on the bioavailability of compatible medicinal herbs is still unknown. Objectives: To explore the effect of a carbonized herbal medicine on the in vivo adsorption and release and absorption of other active pharmaceutical ingredients in a compound prescription. Methods: The bioavailability of carbonized Herba schizonepetae (CHS) to eight active components (epiberberine, coptisine, palmatine, berberine, phellodendrine, aesculin, aesculetin, and anemoside B4) in the aqueous extract of Pulsatillae Decoction (PDAE) was evaluated by the in vitro adsorption and release and in vivo pharmacokinetics tests. Activated carbon (AC) was used as the control. Results: In vitro experiment showed that the cumulative adsorption rates of CHS to the eight active components were 33.17%, 54.32%, 21.48%, 42.01%, 39.1%, 25.11%, 32.11%, and 23.08% which was characterized by copsitine > berberine > phellodendrine > epiperberine > aesculetin > anemoside B4 > palmatine., and they were significantly lower than those of AC. The stable release concentration in sequence was 3.23, 3.04, 3.32, 7.29, 3.17, 2.80, 1.45, and 3.81 μg/mL, which was characterized by berberine > anemoside B4 > palmatine > epiberberine > phellodendrine > coptisine > aesculin > aesculetin, and they were significantly higher than those of AC. The animal experiment indicated that the areas under the concentration-time curve (AUC0-∞) of epiberberine, berberine, aesculetin, and anemoside B4 in PDAE+CHS group were significantly higher than those in the PDAE and PDAE+AC groups, and the other four components in the PDAE+CHS group were lower than those in PDAE group but higher than those in PDAE+AC group. Conclusion: CHS could significantly improve the bioavailability of epiberberine, berberine, aesculetin, and anemoside B4 in Pulsatillae Decoction and has a sustained-release effect on berberine, aesculin, aesculetin, and anemoside B4.