New therapeutic aspects of flavones: the anticancer properties of Scutellaria and its main active constituents Wogonin, Baicalein and Baicalin

Use of isoform-specific UGT metabolism to determine and describe rates and profiles of glucuronidation of wogonin and oroxylin A by human liver and intestinal microsomes

PURPOSES

Glucuronidation via UDP-glucuronosyltransferases (or UGTs) is a major metabolic pathway. The purposes of this study are to determine the UGT-isoform-specific metabolic fingerprint (or GSMF) of wogonin and oroxylin A, and to use isoform-specific metabolism rates and kinetics to determine and describe their glucuronidation behaviors in tissue microsomes.

METHODS

In vitro glucuronidation rates and profiles were measured using expressed UGTs and human intestinal and liver microsomes.

RESULTS

GSMF experiments indicated that both flavonoids were metabolized mainly by UGT1As, with major contributions from UGT1A3 and UGT1A7-1A10. Isoform-specific metabolism showed that kinetic profiles obtained using expressed UGT1A3 and UGT1A7-1A10 could fit to known kinetic models. Glucuronidation of both flavonoids in human intestinal and liver microsomes followed simple Michaelis-Menten kinetics. A comparison of the kinetic parameters and profiles suggests that UGT1A9 is likely the main isoform responsible for liver metabolism. In contrast, a combination of UGT1As with a major contribution from UGT1A10 contributed to their intestinal metabolism. Correlation studies clearly showed that UGT isoform-specific metabolism could describe their metabolism rates and profiles in human liver and intestinal microsomes.

CONCLUSION

GSMF and isoform-specific metabolism profiles can determine and describe glucuronidation rates and profiles in human tissue microsomes.

Secondary metabolite mapping identifies Scutellaria inhibitors of human lung cancer cells

Scutellaria baicalensis root is widely used in China as an adjuvant to orthodox chemotherapy of lung cancer. However, functional biomarkers of this plant for anti-lung cancer activity have not yet been reported. We therefore determined the growth inhibition activity by MTT assay of eight solvent extracts of S. baicalensis in the human lung cancer cell line SK-MES-1. This activity was then mapped onto the secondary metabolite profile of crude extracts by principal components analysis (PCA) of proton NMR and HPLC-UV data. NMR- and HPLC-PCA maps revealed highest inhibitory activity for the non-aqueous extracts. The first two components of both maps discriminated extract activity mainly based on the differential content of three compounds, which were then tested individually. The IC(50) values for baicalin (IC(50): 64+/-5 microM), baicalein (IC(50): 80+/-6 microM) and wogonin (IC(50): 39+/-10 microM) were comparable to that of the antineoplastic cisplatin (IC(50): 79+/-16 microM). A partial least squares regression (PLS)-NMR model highly correlated with the corresponding PLS-HPLC model for prediction of inhibition. Secondary metabolite mapping of lung cancer growth inhibitors in crude extracts may be an important first step to qualify Chinese herbal prescriptions required for meaningful clinical trials of such integrated therapies.

The genus Scutellaria an ethnopharmacological and phytochemical review

Scutellaria (HUANG QIN) (Lamiaceae), which includes about 350 species commonly known as skullcaps, is widespread in Europe, the United States and East Asia. Some species are taken to clear away the heat-evil and expel superficial evils in traditional Chinese medicine (TCM). The present paper reviews the ethnopharmacology, the biological activities and the correlated chemical compounds of Scutellaria species. More than 295 compounds have been isolated, among them flavonoids and diterpenes. Studies show that Scutellaria and its active principles possess wide pharmacological actions, such as antitumor, anti-angiogenesis, hepatoprotective, antioxidant, anticonvulsant, antibacterial and antiviral activities. Currently, effective monomeric compounds or active parts have been screened for pharmacological activity from Scutellaria in vivo and in vitro. Increasing data supports application and exploitation for new drug development.

Synergistic effect of magnetic nanoparticles of Fe(3)O(4) with gambogic acid on apoptosis of K562 leukemia cells

Gambogic acid (GA) has a significant anticancer effect on a wide variety of solid tumors. Recently, many nanoparticles have been introduced as drug-delivery systems to enhance the efficiency of anticancer drug delivery. The aim of this study was to investigate the potential benefit of combination therapy with GA and magnetic nanoparticles of Fe₃O₄ (MNPs-Fe₃O₄). The proliferation of K562 cells and their cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscope and flow cytometry, respectively. Furthermore, real-time polymerase chain reaction and Western blotting analyses were performed to examine gene transcription and protein expression, respectively. The results showed that MNPs-Fe₃O₄ dramatically enhanced GA-induced cytotoxicity and apoptosis in K562 cells. The typical morphological features of apoptosis treated with GA and MNPs-Fe₃O₄ were observed under an optical microscope and a fluorescence microscope, respectively. The transcription of caspase-3 and bax gene in the group treated with GA and MNPs-Fe₃O₄ was higher than that in the GA-alone group or MNPs-Fe₃O₄-alone group, but the transcription of bcl-2, nuclear factor-κB, and survivin degraded as did the expression of corresponding proteins in K562 cells. Our data suggests a potential clinical application of a combination of GA and MNPs-Fe₃O₄ in leukemia therapy.

SH21B, an anti-obesity herbal composition, inhibits fat accumulation in 3T3-L1 adipocytes and high fat diet-induced obese mice through the modulation of the adipogenesis pathway

ETHNOPHARMACOLOGICAL RELEVANCE

SH21B is an anti-obesity composition composed of seven herbs: Scutellaria baicalensis Georgi, Prunus armeniaca Maxim, Ephedra sinica Stapf, Acorus gramineus Soland, Typha orientalis Presl, Polygala tenuifolia Willd and Nelumbo nucifera Gaertner. It has been used for the treatment of obesity in traditional medical clinics in Korea, but its anti-obesity effects and mechanism of action have not been studied until now.

AIM OF THE STUDY

This study was conducted to confirm the anti-obesity effects of SH21B and to elucidate its mechanism of action.

MATERIALS AND METHODS

3T3-L1 adipocytes and high fat diet-induced obese mice were treated with SH21B, and its effect on gene expression was analyzed using microarray technology, real-time PCR and western blotting experiments.

RESULTS

SH21B significantly inhibited fat accumulation in 3T3-L1 adipocytes and reduced adipose tissue and serum triglyceride levels in high fat diet-induced obese mice. Microarray analyses showed that SH21B affected more genes in the adipogenesis pathway than any other pathway studied. SH21B significantly decreased the expression of major transcription factors of the adipogenesis pathway and resulted in the down-regulation of lipid metabolizing enzymes involved in the transport, uptake and synthesis of lipids.

CONCLUSIONS

SH21B inhibits fat accumulation by down-regulating the expression of genes involved in the adipogenesis pathway.

Baicalin attenuates oxygen-glucose deprivation-induced injury by inhibiting oxidative stress-mediated 5-lipoxygenase activation in PC12 cells

AIM

To determine whether the flavonoid baicalin attenuates oxygen-glucose deprivation (OGD)-induced injury by inhibiting oxidative stress-mediated 5-lipoxygenase (5-LOX) activation in PC12 cells.

METHODS

The effects of baicalin and the 5-LOX inhibitor zileuton on the changes induced by OGD/recovery or H(2)O(2) (an exogenous reactive oxygen species [ROS]) in green fluorescent protein-5-LOX-transfected PC12 cells were compared.

RESULTS

Both baicalin and zileuton attenuated OGD/recovery- and H(2)O(2)-induced injury and inhibited OGD/recovery-induced production of 5-LOX metabolites (cysteinyl leukotrienes) in a concentration-dependent manner. However, baicalin did not reduce baseline cysteinyl leukotriene levels. Baicalin also reduced OGD/recovery-induced ROS production and inhibited 5-LOX translocation to the nuclear envelope and p38 phosphorylation induced by OGD/recovery and H(2)O(2). In contrast, zileuton did not show these effects.

CONCLUSION

Baicalin can inhibit 5-LOX activation after ischemic injury, which may partly result from inhibition of the ROS/p38 mitogen-activated protein kinase pathway.

Selective fraction of Scutellaria baicalensis and its chemopreventive effects on MCF-7 human breast cancer cells

Based on our previous observation, the whole Scutellaria baicalensis extract (SbE) did not show significant breast cancer cell inhibitory effect. In this study, we isolated a baicalin-deprived-fraction (SbF1) of Scutellaria baicalensis, and baicalin-fraction (SbF3), and evaluated their anti-breast cancer properties using MCF-7 cells. The content of four flavonoids in extract/fractions were determined using high performance liquid chromatography. Analytical data showed that in SbF1, the major constituents are baicalein and wogonin, while SbF3 only contains baicalin. The antiproliferative effects of fractions and SbE were assayed using modified trichrome stain method. SbF1 showed significant antiproliferative effect. Treated with 100mug/ml of SbF1 for 72h inhibited MCF-7 cell growth by 81.6%, while in the same treatment concentration, SbF3 increased cell growth by 22.6%. SbF1 was recognized as an active fraction of SbE. The effects of four flavonoids in SbE, scutellarin, baicalin, baicalein and wogonin, were determined, and data showed that baicalein and wogonin significantly inhibited MCF-7 cell growth. In contrast, in certain concentrations, scutellarin and baicalin increased cancer cell growth. The effects of SbF1 on cell cycle and apoptosis were assayed using flow cytometry. SbF1 arrested MCF-7 cells in S- and G2/M-phases, and significantly increased induction of cell apoptosis. These combined phytochemical and biological data provide evidence for further chemopreventive studies of the baicalin-deprived SbE on breast cancer.

Protective effect of Bojungbangdocktang on cisplatin-induced cytotoxicity and apoptosis in MCF-10A breast endothelial cells

Although cisplatin has been extensively used as a cancer chemotherapeutic agent for the treatment of various human cancers, it causes significant side effects such as nephrotoxicity and hepatotoxicity due to lethal bystander damage to normal cells. Thus, in the current study, we investigated the Oriental herbal medicine Bojungbangdocktang (BJBDT), as we reported previously its anti-angiogenic activity at nontoxic concentrations that could prevent cisplatin-induced toxicity and apoptosis in human normal breast epithelial cell MCF-10A, but not in MCF-7 and MDA MB-231 breast cancer cells. BJBDT protected cisplatin-induced cytotoxicity in MCF-10A cells and potentiated cytotoxicity and MMP loss in MCF-7 cells. Also, 4',6-diamidino-2-phenylindole (DAPI) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay revealed that BJBDT reduced cisplatin-induced apoptotic bodies in MCF-10A cells compared with cisplatin-treated control. Consistently, BJBDT attenuated the apoptotic portion sub-G1 DNA contents as well as blocked the activation of caspase-3 and -9 and poly(ADP-ribose)polymerase (PARP) cleavage in cisplatin-treated MCF-10A cells. Taken together, our findings suggest that BJBDT can protect cisplatin-induced cytotoxicity and apoptosis in normal MCF-10A breast cells as a cancer chemopreventive agent.

Hot topics in Chinese herbal drugs research documented in PubMed/MEDLINE by authors inside China and outside of China in the past 10 years: based on co-word cluster analysis

OBJECTIVE

This study aims to gain an overview of hot topics related to research focused on Chinese herbal drugs by authors inside China and outside of China in the past 10 years.

METHODS

PubMed/MEDLINE was utilized in order to investigate and select research that was published on "Chinese herbal drugs" from 1998 to 2007, by authors located both inside and outside of China (MeSH terms were downloaded and ranked). MeSH terms that frequently appeared were identified and co-word analysis was carried out for two groups: (1) authors located in China, and (2) authors based outside of China, respectively. The hot topics concerning research into Chinese herbal drugs were concluded after cluster analysis and related document analysis.

RESULTS

For authors in the China group versus those outside the China group, the search results were 4790 versus 2609 citations and approximately 40,000 versus 20,000 MeSH terms, respectively. The threshold value of highly frequent terms was set at 30 versus 20, and the cumulative frequency percentage of these terms was 40.92% versus 36.67%, respectively. Thus, 43 highly frequent MeSH terms were identified and 43 x 43 co-word matrices were acquired for each group. The appearance frequency of MeSH showed that most research focused on pharmacology, therapeutic application, phytotherapy, side-effects of Chinese herbal drugs, and identification of active chemical components in herbs.

CONCLUSION

The hot topics are as follows: (1) anti-inflammatory activity, antioxidant activities, anticancer activity of phytogenic antineoplastic agents, and neuroprotective effects of Chinese herbal drugs; (2) common diseases treated with Chinese herbal drugs include hepatocirrhosis, diabetes, angina, chronic hepatitis B in China, and diabetes, asthma, prostate cancer, and hepatocirrhosis outside of China; (3) Chinese herbal nephropathy and acute hepatitis induced by Chinese herbal drugs; (4) PC-SPES (PDQ) for the treatment of prostate cancer, which was a hot topic for researchers located outside of China; (5) research on extraction of active components from medicinal plants; and finally (6) research related to the identification of the Chinese herbal drugs component with state-of-the-art technologies in China.