PT  - JOURNAL ARTICLE
AU  - Leslie J. Dickmann
AU  - Brooke M. VandenBrink
AU  - Yvonne S. Lin
TI  - In Vitro Hepatotoxicity and Cytochrome P450 Induction and Inhibition Characteristics of Carnosic Acid, a Dietary Supplement with Antiadipogenic Properties
AID  - 10.1124/dmd.112.044909
DP  - 2012 Jul 01
TA  - Drug Metabolism and Disposition
PG  - 1263--1267
VI  - 40
IP  - 7
4099  - http://dmd.aspetjournals.org/content/40/7/1263.short
4100  - http://dmd.aspetjournals.org/content/40/7/1263.full
SO  - Drug Metab Dispos2012 Jul 01; 40
AB  - Carnosic acid is a phenolic diterpene isolated from rosemary (Rosmarinus officinalis), which may have anticancer, antiadipogenic, and anti-inflammatory properties. Recently, carnosic acid was shown to prevent weight gain and hepatic steatosis in a mouse model of obesity and type II diabetes. Based on these results, carnosic acid has been suggested as a potential treatment for obesity and nonalcoholic fatty liver disease; however, little is known about the safety of carnosic acid at doses needed to elicit a pharmacological effect. For this reason, hepatotoxicity and cytochrome P450 inhibition and induction studies were performed in primary human hepatocytes and microsomes. Measuring cellular ATP, carnosic acid showed a dose-dependent increase in hepatotoxicity with an EC50 value of 94.8 ± 36.7 μM in three human hepatocyte donors without a concurrent increase in the apoptosis markers caspase-3/7. In human liver microsomes, carnosic acid did not exhibit significant time-dependent inhibition for any of the cytochrome P450 enzymes investigated, although it did inhibit CYP2C9- and CYP3A4-catalyzed reactions with Ki values of 9.2 and 4.3 μM, respectively. Carnosic acid also induced CYP2B6 and CYP3A4 mRNA and enzyme activity in a dose-dependent manner. At 10 μM, carnosic acid increased CYP2B6 enzyme activity 61.6 and 49.3% in two donors compared with phenobarbital, and it increased CYP3A enzyme activity 82.6 and 142% compared with rifampicin. These results indicate the potential for drug interactions with carnosic acid and illustrate the need for an appropriate safety assessment before being used as a weight loss supplement.