likviriton and brucine

Semen Strychni is known for its treatment of rheumatic arthritis with a low therapeutic index. Liquorice contributes a lot in herb detoxification according to the traditional Chinese medicine theory. A simple, rapid, and sensitive liquid chromatography-mass spectrometric method (LC-MS) was developed and validated for simultaneous determination of main bioactive ingredients in liquorice and Semen Strychni in rat plasma. Using moclobemide and cyproterone acetate as the internal standards, the analytes were pretreated via protein precipitation with methanol. An Ultimate AQ-C18 column (3.0 μm, 3.0 × 100 mm) was employed for chromatographic separation, combining with gradient elution. The mobile phase consisted of 0.07% formic acid and 0.12% ammonium acetate in aqueous phase (A) and acetonitrile in organic phase (B). The elution program was as follows: 0-0.5 min, 20% B; 0.5-1 min, 20-60% B; 1-7 min, 60-85% B; and 7-7.5 min, returned to 20% B, then continued to 12 min. Selected reaction monitoring was performed in both positive and negative ESI. Positive mode was adopted for detection of strychnine, brucine, and moclobemide, while negative mode was used for glycyrrhizic acid, glycyrrhetinic acid, liquiritigenin, isoliquiritigenin, liquiritin, and cyproterone acetate. The method was validated for specificity, linearity, matrix effect, recovery, precision, accuracy, and stability. The results show that this method is sensitive, accurate and robust for biological matrix analysis. Moreover, the proposed method was applied to a pharmacokinetic study in Sprague-Dawley rats for investigating the mechanism of which liquorice detoxifies Semen Strychni.

Topics: Animals; Chromatography, Liquid; Flavanones; Glucosides; Glycyrrhiza; Glycyrrhizic Acid; Plasma; Rats; Reproducibility of Results; Semen; Strychnine

Abstract: The activities of four CYP450 enzymes (CYP3A, 1A2, 2El and 2C) and the mRNA expression levels of CYP1A2, 2El, 2Cll and 3A1 in rat liver were determined after Wistar rats were orally administered with brucine (BR) at three dosage levels (3, 15 and 60 mg.kg-1 per day) and the high dose of BR combined with glycyrrhetinic acid (GA, 25 mg.kg-1 per day) or liquiritin (LQ, 20 mg.kg-1 per day) for 7 consecutive days. Compared with the control, brucine caused 24.5% and 34.6% decrease of CYP3A-associated testosterone 6beta-hydroxylation (6betaTesto-OH) and CYP2C-associated tolbutamide hydroxylation (Tol-OH), respectively, and 146.1% increase of CYP2El-associated para-nitrophenol hydroxylation (PNP-OH) at the high dose level. On the other hand, (BR+GA) caused 51.4% and 33.5% decrease, respectively, of CYP2El-associated PNP-OH and CYP1A2-associated ethoxyresorufin-O-de-ethylation (EROD) as compared with the high dose of BR group. Meanwhile, (BR+LQ) caused 41.1% decrease of CYP2El-associated PNP-OH and 37.7% increase of CYP2C-associated Tol-OH. The results indicated that the co-administration of BR with GA or LQ had effect on mRNA expression and activities of the CYP450 enzymes mentioned above to some extent, and the in vivo antagonism of LQ on BR-induced CYPs adverse effects and the in vivo inhibitory action of GA on CYP2E1 and 1A2 might play an important role in the detoxification of Radix Glycyrrhizae against Strychnos nux-vomica L.

Topics: Animals; Aryl Hydrocarbon Hydroxylases; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP2E1; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 2; Flavanones; Gene Expression Regulation, Enzymologic; Glucosides; Glycyrrhetinic Acid; Hydroxylation; Liver; Male; Nitrophenols; Plants, Medicinal; Rats; Rats, Wistar; RNA, Messenger; Steroid 16-alpha-Hydroxylase; Steroid Hydroxylases; Strychnine; Strychnos nux-vomica; Tolbutamide