In vitro differences in toddalolactone metabolism in various species and its effect on cytochrome P450 expression

Context Toddalolactone, the main component of Toddalia asiatica (L.) Lam. (Rutaceae), has anticancer, antihypertension, anti-inflammatory, and antifungal activities. Objective This study investigated the metabolic characteristics of toddalolactone. Materials and methods Toddalolactone metabolic stabilities were investigated by incubating toddalolactone (20 mu M) with liver microsomes from humans, rabbits, mice, rats, dogs, minipigs, and monkeys for 0, 30, 60, and 90 min. The CYP isoforms involved in toddalolactone metabolism were characterized based on chemical inhibition studies and screening assays. The effects of toddalolactone (0, 10, and 50 mu M) on CYP1A1 and CYP3A5 protein expression were investigated by immunoblotting. After injecting toddalolactone (10 mg/kg), in vivo pharmacokinetic profiles using six Sprague-Dawley rats were investigated by taking 9-time points, including 0, 0.25, 0.5, 0.75, 1, 2, 4, 6 and 8 h. Results Monkeys showed the greatest metabolic capacity in CYP-mediated and UGT-mediated reaction systems with short half-lives (T (1/2)) of 245 and 66 min, respectively, while T (1/2) of humans in two reaction systems were 673 and 83 min, respectively. CYP1A1 and CYP3A5 were the major CYP isoforms involved in toddalolactone biotransformation. Induction of CYP1A1 protein expression by 50 mu M toddalolactone was approximately 50% greater than that of the control (0 mu M). Peak plasma concentration (C (max)) for toddalolactone was 0.42 mu g/mL, and T (max) occurred at 0.25 h post-dosing. The elimination t (1/2) was 1.05 h, and the AUC(0-t) was 0.46 mu g/mL/h. Conclusions These findings demonstrated the significant species differences of toddalolactone metabolic profiles, which will promote appropriate species selection in further toddalolactone studies.

Automated summary

This study investigated the metabolic characteristics of toddalolactone, the main component of Toddalia asiatica (L.) Lam. The results showed significant species differences in toddalolactone metabolic profiles, which will be helpful for appropriate species selection in further studies of toddalolactone. Toddalolactone exhibited induction effects on CYP1A1 and CYP3A5 protein expression and had different pharmacokinetic profiles in rats.