Baicalein attenuates cardiac hypertrophy in mice via suppressing oxidative stress and activating autophagy in cardiomyocytes.

Baicalein is a natural flavonoid extracted from the root of Scutellaria baicalensis that exhibits a variety of pharmacological activities. In this study, we investigated the molecular mechanisms underlying the protective effect of baicalein against cardiac hypertrophy in vivo and in vitro. Cardiac hypertrophy was induced in mice by injection of isoproterenol (ISO, 30 mg·kg-1·d-1) for 15 days. The mice received caudal vein injection of baicalein (25 mg/kg) on 3rd, 6th, 9th, 12th, and 15th days. We showed that baicalein administration significantly attenuated ISO-induced cardiac hypertrophy and restored cardiac function. The protective effect of baicalein against cardiac hypertrophy was also observed in neonatal rat cardiomyocytes treated with ISO (10 µM). In cardiomyocytes, ISO treatment markedly increased reactive oxygen species (ROS) and inhibited autophagy, which were greatly alleviated by pretreatment with baicalein (30 µM). We found that baicalein pretreatment increased the expression of catalase and the mitophagy receptor FUN14 domain containing 1 (FUNDC1) to clear ROS and promote autophagy, thus attenuated ISO-induced cardiac hypertrophy. Furthermore, we revealed that baicalein bound to the transcription factor FOXO3a directly, promoting its transcription activity, and transactivated catalase and FUNDC1. In summary, our data provide new evidence for baicalein and FOXO3a in the regulation of ISO-induced cardiac hypertrophy. Baicalein has great potential for the treatment of cardiac hypertrophy.

[Determination of cyclovirobuxine D by RP-HPLC with precolumn fluorescence derivatization].

AIM: To establish a RP-HPLC method for determination of cyclovirobuxine D. METHODS: Cyclovirobuxine D reacted with a derivative reagent 1-naphthyl isocyanate in chloroform to form fluorescence derivatives, stopped the reaction by adding the mobile phase and then directly injected the solution into the chromatograph to seperate it by RP-HPLC. The analysis was carried out on C18 column, the mobile phase is methanol-water (85:15), the excitation wavelength was set at 305 nm, emission at wavelength 385 nm, and the flow rate was 1 mL.min-1. The effect of several factors including the reaction medium, temperature, time and amount of 1-naphthyl isocyanate on the yield of the derivatization was also investigated systematically. RESULTS: A simple and rapid RP-HPLC method for the simultaneous isolation and analysis of cyclovirobuxine D and its related substances was developed, and the absence of interference between the derivative peak responses of cyclovirobuxine D and its related substances were verified by UV diode array detecter and MS. The linearity was obtained from 0.75 microgram.mL-1 to 2.5 micrograms.mL-1 of cyclovirobuxine D derivatives with a correlation coefficient of 0.9991. The detection limit of cyclovirobuxine D derivative was 1 ng.mL-1, the repeatability of derivatization was good with relative standard derivation no more than 1.2% and derivative was stable within 48 h. The method described conforms to the validation of China Pharmacopiea compendial methods used for pharmaceutical products in general. CONCLUSION: The established method is proved to be reliable quantitative method for the quality control of cyclovirobuxine D.