Corticosterone, a principal glucocorticoid synthesized in the rodent adrenal cortex, can be cumulatively toxic to hippocampal neurons, the cause of which is not known. The present study determined whether the cytosol adenylate kinase (AK) system was involved in the neuronal damage induced by long-term exposure to high corticosterone levels. We investigated the effects of long-term exposure to high corticosterone levels on AK1 activity, AK1 mRNA expression, and energy levels in cultured hippocampal neurons. The results show that long-term exposure to high corticosterone levels induces a reduction of the cultured hippocampal neuron viability, significantly reduces energy levels, and causes a time-dependant reduction of the AK1 activity. These findings indicate that changes in the AK system might be the mechanism underlying neuronal damage induced by long-term exposure to high corticosterone levels.

A simple, reliable, economical method was developed using HPLC with a diode-array detector for determination of total flavonoids in plasma after introvenous administration of ginkgo biloba extract. The method simultaneously detects quercetin, kaempferol, and isorhamnetin after acid hydrolysis and recalculation. The hydrolysis and extraction conditions were optimized in an orthogonal test. The specificity was tested by comparing the retention time, UV spectra, and peak purity indices with standards. The detection limits were 20 ng/mL for quercetin, 20 ng/mL for kaempferol, and 50 ng/mL for isorhamnetin. The calibration curve ranges were 75-2400, 71-2280, and 70-2240 ng/mL. The pharmacokinetic characteristics of ginkgo biloba flavonoids after venous administration of 50 mg/kg ginkgo biloba extract to rats were analyzed using a two-compartment model. The initial plasma concentration was 171.22 μg/mL. The half-life of flavonoids in the first compartment (distribution) was 0.07 h and at the second compartment (elimination) was 4.51 h, while the AUC_(0-∞) was 1711.06 μg·min/mL. The apparent volume of distribution was 0.11 L/kg. The total body clearance is 10.52 mL/(min·kg). The result shows the method is suitable for pharmacokinetic studies.

A series of animal models are used to investigate the anti-depression mechanism of flavonoids in scutellariae radix (SR) in vivo. Depression-like behavior in mice was studied after intraperitoneal administration of SR. The results showed that SR administered to mice by the intraperitoneal route obviously shortened the duration in the tail suspension test and the forced swimming test, aggravated the symptoms of eyelid ptosis, akinesia, and mortality caused by reserpine, prolonged climbing times, affected the conditioned place preference, and increased sugar consumption in mice. However the SR did not affect the head twitches induced by 5-HTP, locomotor activity in mice, the toxicity of yohimbine, and the body temperature decrease caused by high dosage of apomorphine. The tests show that SR has some anti-depression effect related to the dopamine system. Furthermore another anti-depression mechanism was possible that could affect the mechanism of brain reward, bring positive reinforcement, and increase the sensitivity to euphoria in mice.

Previous studies have shown that mice experiencing cerebral ischemia reperfusion (CIR) and stress can serve as a model of post stroke depression (PSD). The present study verified the acute antidepressant effects of radix puerariae extract (PE) on PSD mice through behavior and gene expression experiments. CIR was found to reduce the sucrose consumption and tyrosine hydroxylase (TH) gene expression. PE administration after CIR surgery was observed to significantly enhance the mRNA expression of TH in the hippocampus compared with the PSD group on Day 0 and Day 3 postsurgery. These findings indicate that PE contributes to the amelioration of behavior response in PSD mice, which is closely related with the protective effects of catecholamine synthesize against CIR brain damage.

Antioxidant activities of the 95% ethanol extract from Caesalpinia sappan heartwood (ECS), protosappanin A, protosappanin B, and brazilein were studied in vitro. The inhibition of the formation of malondialdehyde (MDA) and the scavenging of superoxide anions, hydrogen peroxide, and hydroxyl radicals were assayed. The experimental results show that all four substances had antioxidant activity in vitro but their capabilities differed for the different indicators. ECS, protosappanin A, and protosappanin B show more inhibition of MDA and scavenging of hydrogen peroxide, while brazilein shows more scavenging of hydroxyl radicals. All the samples show little scavenging of superoxide anions.

Ellagic acid (EA) has aroused great interest worldwide owing to its antioxidant, anti-inflammatory, and anticarcinogenetic properties. The EA content in pomegranate leaf was measured in this study using high performance liquid chromatography to investigate the effects of season, variety, and processing method on the EA level. The results show that the EA content in 11 varieties of pomegranate from the Zaozhuang region in China range from 1.30 mg · g^–1 to 6.46 mg · g^–1 of dry weight in five consecutive seasons from June to October. An analysis of variance (ANOVA) shows that the EA content is significantly dependent on the season (p<0.05). The EA content increases significantly during the growing season to the highest level in September and October. The effect of the leaf variety on the EA content is less significant than the season. The processing methods have different effects on the EA content. Soaking for 24 hours slightly increases the EA content (p<0.05). Heating at 80℃ or 100℃ for 1 h after soaking has little influence on the EA content, while slow-fired cooking at high temperature significantly elevates the EA content (p<0.05). To improve quality and stability, several parameters such as leaf collection time, slow-fired cooking, and cooking time should be strictly controlled during the processing of pomegranate leaf tea and its extract.