Evaluation of in vitro embryotoxicity tests for Chinese herbal medicines.

Chinese herbal medicines (CHMs) have been widely used during pregnancy, but feto-embryo safety tests are lacking. Here we evaluated in vitro embryotoxicity tests (IVTs) as alternative methods in assessing developmental toxicity of CHMs. Ten CHMs were selected and classified as strongly, weakly and non-embryotoxic. Three well validated IVTs and prediction models (PMs), including embryonic stem cell test (EST), micromass (MM) and whole embryo culture (WEC), were compared. All strongly embryotoxic CHMs were predicted by MM and WEC PM2. While all weakly embryotoxic CHMs were predicted by MM and WEC PM1. All non-embryotoxic CHMs were classified by EST, MM, but over-classified as weakly embryotoxic by WEC PM1. Overall predictivity, precision and accuracy of WEC determined by PM2 were better than EST and MM tests. Compared with validated chemicals, performance of IVTs for CHMs was comparable. So IVTs are adequate to identify and exclude embryotoxic potential of CHMs in this training set.

Polysaccharides of Dendrobium officinale Kimura & Migo protect gastric mucosal cell against oxidative damage-induced apoptosis in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium officinale Kimura & Migo (DO) is a valuable Traditional Chinese Medicine to nourish stomach, in which polysaccharides are identified as active ingredients. However, limited scientific evidences have been reported on the gastroprotective efficacy of DO. The aim of the current study was to investigate the protective effects and underlying mechanism of polysaccharides from DO(DOP) on gastric mucosal injury. MATERIAL AND METHODS: For in vitro study, HFE145 cells were pretreated with DOP before induction of cell apoptosis by H2O2. Cell apoptosis and related proteins expression were detected. In the in vivo study, absolute ethanol was administered orally to induce gastric mucosal injury in rat. The gastric mucosal injury area and histological examination were used to evaluate the effects of DOP treatment on the recovery of the gastric mucosal injury. RESULTS: H2O2 treatment for 6h significantly induced cell apoptosis in HFE145 cells. However, the destructive effects of H2O2 on HFE 145 cells could be reversed by the pretreatment with DOP. The increased ROS level induced by H2O2 for 4h was reduced after DOP pretreatment. The number of apoptotic cells in both early and late apoptosis stages decreased significantly and the nuclei morphology changes were improved with DOP pretreatment. Furthermore, DOP inhibited caspase 3 activation and PARP cleavage, downregulated Bax expression and upregulated Bcl2 expression in cell model. Further study revealed that pretreatment of DOP inhibited p -NF-κBp65/NF-κBp65 level, indicating DOP inhibited H2O2-mediated apoptosis via suppression of NF-κB activation. In addition, DOP treatment could ameliorate gastric mucosal injury and inhibit mucin loss induced by ethanol in animal model. DOP treatment also interfered with ethanol-induced apoptosis process by downregulating Bax/Bcl2 ratio in gastric mucosa. CONCLUSIONS: The present study was the first one to demonstrate the gastroprotective effect of DOP through inhibiting oxidative stress-induced apoptosis. This study provided a solid evidence for the potential use of DO as a therapy or health supplement for gastric mucosal diseases.

Mechanisms of the dilator action of the Erigerontis Herba on rat aorta.

ETHNOPHARMACOLOGICAL RELEVANCE: Erigerontis Herba is widely used as a traditional Chinese medicine and is commonly used for neuroprotection and vascular protection. AIM OF STUDY: In this study, the vasodilator effects of Erigerontis Herba (DZXX) were investigated using rat isolated aorta rings. MATERIAL AND METHOD: The involvement of endothelium in the vasorelaxation was studied by comparing response of endothelium-intact and endothelium-denuded aorta rings which precontracted with U46619. The involvement of K(+) channels was studied by pretreatment of the aorta rings with various K(+) channel inhibitors. The involvement of Ca(2+) channel was studied by incubating aorta rings with Ca(2+)-free solution, primed with U46619 prior to elicit contraction by addition of Ca(2+) solution. RESULTS: DZXX (0.2-2mg/ml) induced a concentration-dependent relaxation on U44619-precontracted aorta rings with EC50 of 0.354±0.036mg/ml. Removal of endothelium or pretreatment with a BKCa inhibitor iberiotoxin, KIR inhibitor barium chloride or Kv inhibitor 4-aminopyridine produced no effect on the DZXX-induced vasorelaxation. However, pretreatment with a KATP inhibitor glibenclamide or a non-selective K(+) channel inhibitor tetraethylammonium produced significant inhibition on the DZXX-induced vasorelaxation by 29.9% and 21.3%, respectively. Pretreatment with DZXX (0.4, 1.2 and 2mg/ml) produced a concentration-dependent inhibition on Ca(2+)-induced vasoconstriction. CONCLUSIONS: These results suggest that the vasodilator effect of DZXX was endothelium-independent, mediated by decreasing the influx of Ca(2+) by calcium channel inhibition and increasing the influx of K(+) by opening of a KATP channel.

Bioassay-guided isolation of anti-inflammatory components from the root of Rehmannia glutinosa and its underlying mechanism via inhibition of iNOS pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Rehmannia glutinosa (RR) is commonly used to reduce inflammation in various traditional Chinese herbal formulae; however, little is known regarding its active component(s). AIM OF STUDY: The objective of the present study was to examine the active component(s) responsible for the anti-inflammatory activity of RR via anti-nitric oxide production assay-guided fractionation; and the underlying anti-inflammatory mechanism of action of such component(s) was further investigated. MATERIALS AND METHODS: Anti-nitric oxide (NO) activities with lipopolysaccharides (LPS)-stimulated RAW264.7 murine macrophages was used as screening platform. Gene, protein and inflammatory mediators' expression were also studied using real-time PCR, western blotting and ELISA, respectively. RESULTS: Using anti-NO assay-guided fractionation, sub-fraction C3 (from 31.25 to 62.5 µg/ml, p=0.001 to 0.01) possessed 100-fold more potent anti-inflammatory effect than that of the aqueous extract of RR. Characterization of C3 showed that the anti-inflammatory effect could be partly due to the presence of rehmapicrogenin, which could significantly inhibit NO production (p<0.001). C3 was further demonstrated in blocking inflammation by inhibiting gene (p<0.001) and protein expression of inducible NO synthase (iNOS) dose-dependently. Besides, C3 also significantly inhibited the production of prostaglandin E(2) (p<0.001 to 0.01), IL-6 (p<0.001 to 0.05) and COX-2 (p<0.05). CONCLUSIONS: Rehmapicrogenin was, for the first time, shown to possess nitric oxide inhibitory activities. Bioassay-guided fractionation demonstrated that rehmapicrogenin-containing subfraction C3 exhibited potent anti-inflammatory effect by inhibiting iNOS, COX-2 and IL-6, while rehmapicrogenin was only partially responsible for the anti-inflammatory effect of RR.

The roots of Salvia miltiorrhiza (Danshen) and Pueraria lobata (Gegen) inhibit atherogenic events: a study of the combination effects of the 2-herb formula.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Salvia miltiorrhiza (Danshen) and Pueraria lobata (Gegen) are principle herbs of Chinese herbal formulae which have long been used to treat cardiovascular diseases. AIM OF STUDY: The present study validated the anti-atherogenic effects of three extracts, Danshen alone (DE), Gegen alone (GE) as well as DGE and interpreted their combination effects statistically. MATERIALS AND METHODS: The anti-atherogenic effects of the three extracts were studied in three assays with regards to inflammation, foam cell formation and vascular smooth muscle cell (vSMC) proliferation using lipopolysaccharide (LPS)-induced nitric oxide production model, macrophage foam cell formation model and platelet-derived growth factor (PDGF)-induced vSMC proliferation model, respectively. The combination effects of DGE were statistically analyzed using combination index (CI) and fixed-ratio experimental design. RESULTS: The anti-atherogenic effects of the three extracts including anti-inflammation, anti-foam cell formation and anti-vSMC proliferation were demonstrated in this study. Their combination effects in anti-inflammation, anti-foam cell formation and anti-vSMC proliferation were found to be synergistic, additive and antagonistic, respectively. CONCLUSIONS: This study provided scientific support for the combination use of DGE on atherosclerosis and presented one of the first applications of statistical interpretations of the combination effects of the 2-herb formula.

Reversal of P-glycoprotein-mediated multidrug resistance in human hepatoma cells by hedyotiscone A, a compound isolated from Hedyotis corymbosa.

Multidrug resistance is a major problem in hepatocellular carcinoma. Hedyotiscone A, a compound isolated from Chinese herbal medicine Hedyotis corymbosa (HC, family Rubiaceae), was used as the chemical marker to distinguish between HC and an anticancer herb Hedyotis diffusa (HD) in our previous study. The present study aimed to investigate whether HA exhibited antiproliferative activities in multidrug-resistant hepatocellular carcinoma cells R-HepG2 and the parental cells HepG2 using MTT assay and [(3)H]-thymidine incorporation assay. Our results showed that HA could significantly inhibit cell proliferation in R-HepG2 and HepG2 (IC(50) = 43.7 and 56.3 µg/mL, respectively), but not in normal human liver cells WRL-68 (IC(50) > 100 µg/mL) cells, suggesting its selective cytotoxic effects. Besides, HA induced apoptosis in R-HepG2 cells, as confirmed by annexin-V & propidium iodide staining, and DNA fragmentation assay. The caspase cascade was activated as shown by a significant increase of cleaved caspases-3, -7 and -9 in HA-treated R-HepG2 cells. The activities and protein expression of P-glycoprotein as well as mRNA expression of MDR1 were also decreased in HA-treated R-HepG2 cells. Our study demonstrated for the first time the antiproliferative activities of hedyotiscone A in multidrug-resistant R-HepG2 cells. The findings revealed the potential of this compound in treating multidrug-resistant tumor.