Protective effects of flavonoid extract from Apocynum venetum leaves against corticosterone-induced neurotoxicity in PC12 cells.

Depression is a major psychiatric disorder affecting nearly 21% of the world population and imposes a substantial health burden on society. Although significant progress has been made in depression research, the common molecular mechanism of antidepressants is still far from clearly understood. The neuroprotective effect of antidepressants has been proposed as a possible mechanism. Although Apocynum venetum (AV) L. (Apocynaceae) was previously shown to produce an antidepressant-like effect in the tail suspension test, the mechanisms underlying such antidepressant-like effect are yet to be understood. In this work, we studied the neuroprotective effect of AV leaf flavonoid extract in corticosterone-induced neurotoxicity, using PC12 cells as a suitable in vitro model of depression. Cell viability was quantitated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The release amount of lactic dehydrogenase (LDH) and intracellular Ca(2+) concentration were measured using kit, cell period change was tested by flow cytometry, and transcript abundances of brain-derived neurotrophic factor (BDNF) and microtubule-associated protein 4 (MAP4) were determined by real-time RT-PCR. The results showed that AV extract (25, 50, and 100 µg/ml) increased the A490 nm values, but decreased LDH release and Ca(2+) concentration, suppressed the apoptosis of PC12 cells and up-regulated BDNF and MAP4 transcript abundances compared with the corresponding corticosterone-treated group. These results suggest that the AV extract could generate a neuroprotective effect on corticosterone-induced neurotoxicity in PC12 cells, pointing to a possible action pathway by decreasing the Ca(2+) concentration and up-regulating BDNF and MAP4 genes.

Solvent gradient elution for comprehensive separation of constituents with wide range of polarity in Apocynum venetum leaves by high-speed counter-current chromatography.

A novel gradient elution was efficiently utilized for the separation of the chemical components with a wide range of polarity from the mixed extract of the Chinese medicinal herb Apocynum venetum or mixed standards by high-speed counter-current chromatography. Three sets of solvent systems, n-hexane-ethyl acetate-methanol-water (1.5:3.5:2:4.5 v/v/v/v), ethyl acetate-methanol-water (5:2:5 v/v/v) and n-butanol-methanol-water (5:1:5 v/v/v) were used for the one-step elution. The separation was initiated by filling the column with the lower phase of n-hexane-ethyl acetate-methanol-water (1.5:3.5:2:4.5 v/v/v/v) as a stationary phase followed by elution with the upper phase of n-hexane-ethyl acetate-methanol-water (1.5:3.5:2:4.5 v/v/v/v) to separate the hydrophobic compounds (tail to head). Then the mobile phase was switched to the upper phase of ethyl acetate-methanol-water (5:2:5 v/v/v) to elute the moderate hydrophobic compounds, and finally the hydrophilic compounds still retained in the column were fractionated by eluting the column with the upper phase of n-butanol-methanol-water (5:1:5 v/v/v). A total of 13 compounds including adhyperforin, hyperforin, amentoflavone, biapigenin, quercetin, astragalin, trifolin, isoquercetin, hyperside, acetyled hyperside, rutin, chlorogenic acid and quercetin-3-O-ß-D-glucosyl-ß-D-glucopyranoside were successfully separated via the three sets of solvent systems in one-step operation for 90 min.

[Research on microstructure of caulis herb].

OBJECTIVE: To provide reference for the microscopic identification of caulis herb. METHOD: Systematic arrangement and comparative studies were carried out on the microstructure of medicinal herb of different groups and shapes. RESULT: The rule and characteristics of the microstructure of caulis herb were discussed, and the sorting search list of the microstructure of common caulis herb was established. CONCLUSION: The microstructure characteristics of caulis herb, as the reference of the microscopic identification, are of research value.