High content screening identifies licoisoflavone A as a bioactive compound of Tongmaiyangxin Pills to restrain cardiomyocyte hypertrophy via activating Sirt3

BACKGROUND

Cardiac hypertrophy is a prominent feature of heart remodeling, which may eventually lead to heart failure. Tongmaiyangxin (TMYX) pills are a clinically used botanical drug for treating multiple cardiovascular diseases including chronic heart failure. The aim of the current study was to identify the bioactive compounds in Tongmaiyangxin pills that attenuate cardiomyocytes hypertrophy, and to investigate the underlying mechanism of action.

METHODS AND RESULTS

The anti-hypertrophy effect of TMYX was validated in isoproterenol-induced cardiac hypertrophy model in C57BL/6 mice. After TMYX treatment for 2 weeks, the heart ejection fraction and fractional shortening of the mice model was increased by approximately 20% and 15%, respectively, (p < 0.05). Besides, TMYX dose-dependently reduced the cross section area of cardiomyocytes in the angiotensin-II induced hypertrophy H9c2 model (p < 0.01). Combining high content screening and liquid chromatography mass spectrometry, four compounds with anti-cardiac hypertrophy effects were identified from TMYX, which includes emodin, licoisoflavone A, licoricone and glyasperin A. Licoisoflavone A is one of the compounds with most significant protective effect and we continued to investigate the mechanism. Primary cultures of neonatal rat cardiomyocytes were treated with a hypertrophic agonist phenylephrine (PE) in the presence or absence of licoisoflavone A. After 48 h of treatment, cells were harvested and mitochondrial acetylation was analyzed by western blotting and Image analysis. Interestingly, the results suggested that the anti-hypertrophic effects of licoisoflavone A depend on the activation of the deacetylase Sirt3 (p < 0.01). Finally, we showed that licoisoflavone A-treatment was able to decrease relative ANF and BNP levels in the hypertrophic cardiac cells (p < 0.01), but not in cells co-treated with Sirt3 inhibitors (3-TYP) (p > 0.05).

CONCLUSION

TMYX exerts its anti-hypertrophy effect possibly through upregulating Sirt3 expression. Four compounds were identified from TMYX which may be responsible for the anti-hypertrophy effect. Among these compounds, licoisoflavone A was demonstrated to block the hypertrophic response of cardiomyocytes, which required its positive regulation on the expression of Sirt3. These results suggested that licoisoflavone A is a potential Sirt3 activator with therapeutic effect on cardiac hypertrophy.

Development of a HPLC-MS/MS Method to Determine 11 Bioactive Compounds in Tongmai Yangxin Pill and Application to a Pharmacokinetic Study in Rats

A sensitive and reliable HPLC-MS/MS method has been developed and validated for simultaneous determination of eleven bioactive compounds (rhein, emodin, stilbene glycoside, liquiritin, ononin, verbascoside, gallic acid, schisandrin, liquiritigenin, glycyrrhizic acid, and isoliquiritigenin) in rat plasma after oral administration of Tongmai Yangxin Pill. The collected plasma samples were prepared by liquid-liquid extraction with ethyl acetate after acidification. Eleven compounds were separated on a CORTECS™ C18 column with mobile phases consisting of 0.1% formic acid in deionized water and acetonitrile. The flow rate was 0.3 mL/min. The detection was performed on a tandem mass system with an electrospray ionization (ESI) source in both positive and negative ionization using multiple-reaction monitoring (MRM) mode. The calibration curves were linear over the range of 8-2000 ng/mL for glycyrrhizic acid; 4-1000 ng/mL for liquiritin; 0.8-200 ng/mL for emodin, gallic acid, ononin, schisandrin, and stilbene glycoside; 0.4-100 ng/mL for isoliquiritigenin, liquiritigenin, rhein, and verbascoside, respectively. The intra- and interday precision of the analytes were less than 9.3% and 8.5%. The intra- and interday accuracy were in the range of -14.0% to 10.3% and -6.5% to 9.6%. Meanwhile, the extraction recovery of the analytes in plasma samples ranged from 85.2% to 109.1% and matrix effect from 89.2% to 113.4%. The developed method was successfully applied to the pharmacokinetics of eleven bioactive compounds in rat plasma after oral administration of Tongmai Yangxin Pill prescription.

Developing Neolignans as Proangiogenic Agents: Stereoselective Total Syntheses and Preliminary Biological Evaluations of the Four Guaiacylglycerol 8-O-4'-Coniferyl Ethers

Stereoselective total syntheses of the four stereoisomeric forms of guaiacylglycerol 8-O-4'-coniferyl ether, viz., compounds 1, ent-1, 2, and ent-2, have been established. The key step involves an Evans/Seebach auxiliary-controlled and syn-selective aldol process followed, in the reaction sequences leading to the anti-compounds, by a Mitsunobu reaction involving a benzylic alcohol residue. The proangiogenic properties of the synthetic materials were evaluated in a human microvascular endothelial cell tubule formation assay, thus revealing that they are all active, with the 8S-configured compounds 1 and 2 being the most potent.