Induction of quinone reductase by a methanol extract of Scutellaria baicalensis and its flavonoids in murine Hepa 1c1c7 cells

Deinococcucins A-D, Aminoglycolipids from Deinococcus sp., a Gut Bacterium of the Carpenter Ant Camponotus japonicus

Four new aminoglycolipids, deinococcucins A-D (1-4), were discovered from a Deinococcus sp. strain isolated from the gut of queen carpenter ants, Camponotus japonicus. The structures of deinococcucins A-D were elucidated as a combination of N-acetyl glucosamine, 2,3-dihydroxypropanoic acid, and an alkyl amine with a C₁₆ or C₁₇ hydrocarbon chain primarily based on 1D and 2D NMR and mass spectroscopic data. The exact location of the olefinic double bond in deinococcucins C and D (3 and 4) was assigned based on the liquid chromatography-mass spectroscopy data obtained after olefin metathesis. The absolute configurations of the N-acetyl glucosamine and 2,3-dihydroxy moieties were determined through gas chromatography-mass spectroscopy analysis of authentic samples and phenylglycine methyl ester-derivatized products, respectively. Deinococcucins A and C displayed significant induction of quinone reductase in murine Hepa-1c1c7 cells.

Flavonoids as detoxifying and pro-survival agents: What's new?

The role of flavonoids in the survival machinery of cells has come in the spotlight due to the recent evidence of their effect on the relationship mitochondria-ER stress-proteasome, including the intracellular mechanisms of autophagy and apoptosis. Numerous experimental animal investigations and even human clinical studies have highlighted the major role of these natural compounds in the economy of life and their deep relationship with autotrophic organisms in the evolutionary space. Their role as anti-oxidant and oxidative stress preventive molecules has to date been investigated extensively in the literature. Despite this great amount of promising evidence, many concerns, however, remain, most of which dealing with biochemistry, bioavailability, pharmacokinetics, and interaction of flavonoids with gut microbiome, issues that make difficult any good attempt to introduce these molecules in the human healthcare systems as possible, encouraging therapeutic substances. This review tries to address and elucidate these items.

Mohangic Acids A-E, p-Aminoacetophenonic Acids from a Marine-Mudflat-Derived Streptomyces sp

Mohangic acids A-E (1-5) were isolated from a marine Streptomyces sp. collected from a mudflat in Buan, Republic of Korea. Comprehensive spectroscopic analysis revealed that the mohangic acids are new members of the p-aminoacetophenonic acid class. The relative and absolute configurations of the mohangic acids were determined by J-based configuration analysis and by the application of bidentate chiral NMR solvents followed by (13)C NMR analysis, chemical derivatization, and circular dichroism spectroscopy. Mohangic acid E (5), which is the first glycosylated compound in the p-aminoacetophenonic acid family, displayed significant quinone reductase induction activity.

Hydrophobic flavonoids from Scutellaria baicalensis induce colorectal cancer cell apoptosis through a mitochondrial-mediated pathway

Scutellaria baicalensis extract (SbE) has been shown to exert chemopreventive effects on several types of cancer. Baicalin, a hydrophilic flavonoid found in SbE, may have opposing effects that decrease the antitumor potential of SbE against colorectal cancer. In this study, after removing baicalin, we prepared an aglycone-rich fraction (ARF) of SbE and evaluated its anti-proliferative activity and mechanisms of action. The flavonoids found in ARF, baicalin fraction (BF) and SbE were determined by high-performance liquid chromatography (HPLC). The effects of ARF, BF, SbE and representative flavonoids on the proliferation of HCT-116 and HT-29 human colorectal cancer cells were determined by an MTS assay. The cell cycle, the expression of cyclins A and B1 and cell apoptosis were assayed using flow cytometry. Apoptosis-related gene expression was visualized by quantitative real-time polymerase chain reaction (PCR), and mitochondrial membrane potential was estimated following staining with JC-1. HPLC analysis showed that ARF contained two hydrophobic flavonoids, baicalein and wogonin, and that BF contained only baicalin. SbE had little anti-proliferative effect on the colorectal cancer cells; cancer cell growth was even observed at certain concentrations. ARF exerted potent anti-proliferative effects on the cancer cells. By contrast, BF increased cancer cell growth. ARF arrested cells in the S and G2/M phases, increased the expression of cyclins A and B1, and significantly induced cell apoptosis. Multiple genes in the mitochondrial pathway are involved in ARF-induced apoptosis, and subsequent cellular functional analysis validated the involvement of this pathway. These results suggest that removing baicalin from SbE produces an ARF that significantly inhibits the growth of colorectal cancer cells, and that the mitochondrial apoptotic pathway plays a role in hydrophobic flavonoid-induced apoptosis.

Purification of baicalin and wogonoside from Scutellaria baicalensis extracts by macroporous resin adsorption chromatography

In this study, resin adsorption as a means to separate and purify baicalin and wogonoside from extracts of Scutellaria baicalensis was investigated. Among the ten tested resins, the non-polar resin HPD-100 offered the best adsorption and desorption properties. Langmuir and Freundlich isotherms were used to describe the interactions between solutes and resin at different temperatures, and the equilibrium experimental data were well fitted to the two isotherms. Column packed with HPD-100 resin was used to perform dynamic adsorption and desorption tests to optimize the separation process. After one round treatment with HPD-100 resin, the contents of baicalin and wogonoside were 3.6-fold and 12.0-fold increased with recovery yields of 85.7% and 65.6%, respectively. In addition, a laboratory preparative-scale separation was carried out under the final conditions. The results showed that the preparative separation of baicalin and wogonoside can be easily and efficiently achieved via adsorption and desorption on HPD-100 resin. The developed method is a promising basis for large-scale preparation of baicalin and wogonoside from S. baicalensis extracts.

NRH:quinone reductase 2: an enzyme of surprises and mysteries

Quinone reductase 2 has been discovered in 1961 and rediscovered in 1997. Because of its sequence homology with quinone reductase 1, it has been suspected to detoxify quinones. Ten years later, evidences begin to point to a versatile role of this enzyme. Indeed, QR2 is strongly suspected to be the molecular target of anti-malarian drugs such as chloroquin or paraquine, and of red wine-derived resveratrol that might be responsible for the so-called French paradox. It also is identical to the melatonin binding site MT3, and might therefore be a rationale explanation for the antioxidant role of melatonin. Finally QR2 might be implicated in the toxicity, in vivo, of quinones such as menadione. The present commentary attempts to summarize this information and discusses a series of hypotheses.

Baicalin induces NAD(P)H:quinone reductase through the transactivation of AP-1 and NF-κB in Hepa 1c1c7 cells

Baicalin (5,6,7-trihydroxyflavone-7-O-D-glucuronic acid, BA) is a flavone isolated from Scutellariae radix. In our previous report BA was a major active principle of NAD(P)H:quinone reductase (QR) induction mediated by Scutellariae radix extract and the induction was related to the transcriptional activation of the QR gene in Hepa 1c1c7 cells. The primary aim of the present study was to determine the molecular mechanism of QR gene expression by baicalin. The antioxidant or electrophile response element (ARE/EpRE) found at the 5'-flanking region of phase II genes may play an important role in mediating their induction by xenobiotics, including chemopreventive agents. In accordance, to study the molecular mechanisms of QR gene expression by BA, electrophoretic mobility shift assay (EMSA), using nuclear extracts of treated and untreated cells against ARE, activator protein-1 (AP-1) or nuclear factor-kappaB (NF-kappaB) binding sites, showed that BA increased the binding levels of the parameters in a dose-dependent manner. Further, Hepa 1c1c7 cells were transiently transfected with a plasmid containing three copies of the AP-1- or NF-kappaB-binding site linked to a chloramphenicol acetyltransferase (CAT) reporter gene. Using the CAT reporter gene assay, a dose-dependent transactivation of AP-1- or NF-kappaB-mediated CAT expression was observed with the treatment of BA. These results clearly indicate that BA induces the QR gene expression and activity by transactivation of AP-1 and NF-kappaB, and thus BA may be considered as a potential cancer chemopreventive agent with the induction of phase II detoxification enzyme.

Aqueous extract of herba Scutellaria barbatae, a chinese herb used for ovarian cancer, induces apoptosis of ovarian cancer cell lines

OBJECTIVES

Given the increasingly common use of complementary medicine in cancer patients, we tested the in vitro cytotoxicity of aqueous extracts of 15 traditional Chinese herbs with purported anticancer properties on ovarian and breast cancer cell lines.

METHODS

Cell viability after treatment with herbal extract was measured by metabolism of a tetrazolium substrate. Apoptosis was measured by nuclear and DNA fragmentation and Annexin V binding.

RESULTS

One herb, Herba Scutellaria barbatae, was cytotoxic to 100% (11 of 11) of actively proliferating ovarian lines tested and 50% (2 of 4) of actively proliferating breast cell lines tested. Confluent cultures were resistant to killing by herb, whereas subconfluent cultures were sensitive. Resistant proliferating cell lines expressed higher levels of bcl2. Transfection of the most sensitive ovarian cancer cell line (A2780) with bcl2 resulted in a noticeable protection against apoptosis, but there was no protection in other transfected lines.

CONCLUSIONS

These results will be useful in guiding future studies of herbal aqueous extracts, as well as providing information for clinicians when patients are concurrently using these herbs along with conventional cancer therapies.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

Anticancer activity of Scutellaria baicalensis and its potential mechanism

OBJECTIVE

Scutellaria baicalensis is a widely used Chinese herbal medicine that historically is used in anti-inflammatory and anticancer therapy. The aim of the study is to determine its ability to inhibit human cancer cells in vitro and to determine whether its anticancer activity is because of the inhibition of prostaglandin E(2) (PGE(2)) production that is derived from arachidonic acid through cyclooxygenase-2 (COX-2) pathway.

METHODS

Cell lines from the most common human cancers, including squamous cell carcinoma (SCC-25, KB), breast cancer (MCF-7), hepatocellular carcinoma (HepG2), prostate carcinoma (PC-3 and LNCaP), and colon cancer (KM-12 and HCT-15) were tested. The cells were treated with various concentrations of Scutellaria baicalensis (0.1-100 mg/mL) for 72 hours. Percentage of viable cells after treatment was assessed using a trypan blue dye exclusion assay and the level of PGE(2) production was determined by enzyme immunoassay (EIA).

RESULTS

Scutellaria baicalensis demonstrated a strong dose-dependent growth inhibition in all cell lines. Inhibition concentration at 50% (IC(50)) for HepG2, MCF-7, PC-3, LNCaP, KM-12, HCT-15, KB and SCC-25 cells was 1.1, 0.9, 0.52, 0.82, 1.1, 1.5, 1.0, and 1.2 mg/mL, respectively. Three cell lines (KB, SCC-25, and HepG2) were assessed for the production of PGE(2) and a high level of extracellular (KB and SCC-25) and intracellular PGE(2) (HepG2) was noted. In the presence of Scutellaria baicalensis extract, there was a significant decrease of PGE(2) in a dose-dependent fashion.

CONCLUSIONS

Scutellaria baicalensis strongly inhibits cell growth in all cancer cell lines tested. However, prostate and breast cancer cells (PC-3, LNCaP, and MCF-7) are slightly more sensitive than other type of cancer cells. It also inhibits PGE(2) production, indicating that suppression of tumor cell growth may be due to its ability to inhibit COX-2 activity. This study supports the notion of using Scutellaria baicalensis as a novel anticancer agent to treat various cancers.