Inhibition of dexamethasone-induced cytochrome P450-mediated mutagenicity and metabolism of aflatoxin B1 by Chinese medicinal herbs

Hedyotis diffusa alleviate aflatoxin B1-induced liver injury in ducks by mediating Nrf2 signaling pathway

Aflatoxin B1 (AFB1), the most harmful aflatoxins, is a frequent contamination in feed and food items, raising global concerns in animal production and human public health. Also, AFB1 induces oxidative stress, cytotoxicity, mutations, and DNA lesions through its metabolic transformation into aflatoxin B1-8,9-epoxide (AFBO) by cytochrome P450 (CYP450). Hedyotis diffusa (HD) is a traditional Chinese herbal medicine known for its multiple pharmacological activities, including antioxidant, anti-inflammatory, and immunomodulatory. Yet, the influence of HD on AFB1-induced liver injury in ducks is still unknown. Here, we investigated whether HD positively affects AFB1-induced liver injury in ducks. Results revealed that I) AFB1 caused significant changes in serum biochemical indices and decreased growth performance of ducks (such as ALT, AST, ALP, TP, ALB, final body weight, and body weight gain), whereas HD supplementation at 200 mg/kg mitigated these alterations. II) HD alleviated hepatic histopathological changes and liver index induced by AFB1 in ducks. III) HD significantly attenuated AFB1-induced oxidative stress, as measured by increased antioxidant enzyme activities such as SOD, GPx, and T-AOC and decreased MDA levels. Furthermore, HD reduced the level of AFB1-DNA adduct in duck liver. IV) HD significantly promoted the transcriptional expression of NF-E2-related nuclear factor 2 (Nrf2) and associated genes, including heme oxygenase 1 (HO-1), NAD(P)H dehydrogenase quinone 1 (NQO1), glutamate-cysteine ligase catalytic (GCLC). In conclusion, these results demonstrated that HD could activate the Nrf2 pathway in ducks to reduce the hepatotoxicity driven by AFB1. This finding also provides theoretical and data support for a deeper understanding of the toxic mechanisms of AFB1 and its prevention.

Mitigation of Aflatoxin B1 Hepatoxicity by Dietary Hedyotis diffusa Is Associated with Activation of NRF2/ARE Signaling in Chicks

The objective of this study was to explore the mechanism of Hedyotis diffusa (HD) in mediating the detoxification of aflatoxin B₁ (AFB₁)-induced hepatic injury in chicks. A total of 144 one-day-old male broilers (Cobb 500) were randomly assigned to four treatment groups (n = 6 cages/diet, 6 chicks/cage). After three days of acclimation, the broilers were fed either a control diet (Control), Control plus 0.5 mg/kg of AFB₁, or Control plus 0.5 mg/kg AFB₁ with 500 or 1000 mg/kg HD for two weeks. Both serum and liver were collected at the end of the feeding trial for biochemistry, histology, and NF-E2-related nuclear factor 2 (NRF2)/antioxidant response element (ARE) signaling analysis. Compared with Control, the AFB₁ treatment caused liver injury and decreased (p < 0.05) body weight gain, feed intake, feed conversion ratio, and serum albumin and total protein by 6.2–20.7%. AFB₁ also induced swelling, necrosis, and severe vacuolar degeneration in chicks’ livers. Notably, HD supplementation at 500 and 1000 mg/kg mitigated (p < 0.05) the alterations induced by AFB₁. HD supplementation alleviated (p < 0.05) AFB₁-induced impairment in hepatic glutathione peroxidase activity, protein carbonyl, and exo-AFB₁-8,9-epoxide (AFBO)–DNA concentrations by 57.7–100% and increased (p < 0.05) the activities of superoxide dismutase and catalase by 23.1–40.9% more than those of AFB₁ treatment alone. Furthermore, HD supplementation at the two doses upregulated (p < 0.05) NRF2, NAD(P)H: quinone oxidoreductase-1, heme oxygenase-1, glutathione cysteine ligase catalytic subunit, and glutathione-S transferase A2 and A3 in livers relative to the AFB₁ group by 0.99–3.4-fold. Overall, dietary supplementation of HD at a high dose displayed better protection effects against aflatoxicosis. In conclusion, a dietary HD supplementation at 500 and 1000 mg/kg protected broilers from AFB₁-induced hepatotoxicity, potentially due to the activation of NRF2/ARE signaling in the chicks.

Comprehensive Analysis of Core Genes and Potential Mechanisms in Rectal Cancer

Rectal cancer is a common type of colorectal cancer with high mortality and morbidity. The objective of this study was to identify gene signatures and uncover the potential mechanisms during rectal cancer samples. The gene expression profiles of GSE87211 data set were downloaded from GEO (Gene Expression Omnibus) database. The GSE87211 data set contained 2363 samples, including 203 rectal cancer samples and 160 matched mucosa control samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted, and protein-protein interaction network of differentially expressed genes (DEGs) was performed by Cytoscape. Then, Gene Expression Profiling Interactive Analysis (GEPIA) was applied to get the hub genes expression level and survival analysis between rectum adenocarcinoma (READ) tissues and normal tissues. In total, 846 DEGs were identified, including 402 upregulated genes and 444 downregulated genes. GO analysis showed that upregulated DEGs were enriched in inflammatory response, signal transduction, cell adhesion, immune response, and positive regulation of cell proliferation. KEGG pathway analysis showed that upregulated DEGs were enriched in cytokine-cytokine receptor interaction, Pi3K-Akt signaling pathway, and chemokine signaling pathway. The top 20 hub genes contained IL8, CXCR1, SSTR2, SST, CXCR2, GALR1, GAL, CXCL1, SSTR1, NPY1R, NPY, AGT, PPY, PPBP, CXCL2, CXCL6, CXCL11, CXCL3, GNG4, and GNGT1, and only four genes significantly increased expression levels with obvious changes of survival analysis in READ tissues based on GEPIA. Our study indicated that identified DEGs might promote our understanding of molecular mechanisms, which might be used as molecular targets or diagnostic biomarkers for the treatment of rectal cancer.

A comparable, chemical and pharmacological analysis of the traditional Chinese medicinal herbs Oldenlandia diffusa and O. corymbosa and a new valuation of their biological potential

The herb of Oldenlandia diffusa (Willd.) Roxb. (Family Rubiaceae) is well-known in Chinese folk medicine for the treatment of hepatitis and malignant tumors of the liver, lung and stomach. However, another herb of O. corymbosa (L.) Lam is also used interchangeably in South China for treating the same conditions. To compare the efficacy of the two herbs, the antiproliferative effect of their extracts and the antiangiogenic activity of their main constituents were appraised. The Sulforhodamine B (SRB) assay in human hepatoma HepG2 cells and human colon carcinoma CaCo2 cells and the zebrafish angiogenic model were used for this purpose. The results showed almost no antiproliferative effect of the methanol extracts from O. diffusa and O. corymbosa, while the chloroform extracts exhibited slightly antiproliferative effects. The main components had almost no effect on zebrafish angiogenic vessel formation at the concentrations tested. The results suggest that the mechanism of antitumor activity of O. diffusa may not be attributed to the antiproliferative and antiangiogenic effects.

Chemoprevention of Scutellaria bardata on human cancer cells and tumorigenesis in skin cancer

Scutellaria barbata D. Don (Lamiaceae) (SB) is a perennial herb, which is natively distributed throughout Korea and southern China. This herb is known in traditional Chinese medicine as Ban-Zhi-Lian and in traditional Korean medicine as Banjiryun. SB has been used as an antiinflammatory and antitumor agent. The SB showed strong growth-inhibitory activity and cancer chemopreventive activity in assays representing three major stages of carcinogenesis. The SB was found to act as an antimutagen; it mediated antiinflammatory effects; inhibited cyclooxygenase and hydroperoxidase functions (antipromotion activity). In addition, SB inhibited the development of preneoplastic lesions in carcinogen-treated mouse mammary glands in culture and inhibited tumorigenesis in a mouse skin cancer model. On the other hand, an inhibitory effect of SB on the growth of gynecological cancer cell lines such as HeLa cell and human ovary cancer (HOC) was shown. When HOC cells were treated with SB, the expression of cyclooxygenase-2 was inhibited. These data suggest that SB merits investigation as a potential cancer chemopreventive agent in humans, especially in gynecological cancers.

Caspase Activation and Extracellular Signal-Regulated Kinase/Akt Inhibition Were Involved in Luteolin-Induced Apoptosis in Lewis Lung Carcinoma Cells

Luteolin was isolated from Scutellaria barbata D. Don (S. barbata). In the present study, we examined the underlying molecular mechanism of luteolin and its effect on in vivo tumor growth of Lewis lung carcinoma (LLC) cells. Luteolin exhibited antiproliferative activity against LLC cells with IC50 of 12 microM. Luteolin effectively increased Annexin-V-positive cells as well as sub G1 DNA portion as seen on flow cytometric analysis. Western blotting has revealed that luteolin effectively activates caspase 9 and 3, cleaves poly (ADP-ribose) polymerase (PARP), and increases the ratio of Bax/Bcl-2. Furthermore, mitochondrial membrane potential was reduced by luteolin as seen on fluorescence microscopy. Luteolin downregulated the expression of extracellular signal-regulated kinase (ERK) and Akt in a concentration-dependent manner. In addition, luteolin significantly inhibited the growth of LLC cells implanted on the flank of mice to 40% and 60% of untreated control group values at 2 mg/kg and 10 mg/kg, respectively. Similarly, luteolin significantly reduced the expression of proliferating cell nuclear antigen (PCNA) as well as increased the expression of terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) in tumor section of LLC-bearing mice as determined by immunohistochemistry. Taken together, these results suggest that luteolin exerts antitumor activity by caspase activation and ERK/Akt inhibition.

Caspase Activation and Extracellular Signal-Regulated Kinase/Akt Inhibition Were Involved in Luteolin-Induced Apoptosis in Lewis Lung Carcinoma Cells

Luteolin was isolated from Scutellaria barbata D. Don (S. barbata). In the present study, we examined the underlying molecular mechanism of luteolin and its effect on in vivo tumor growth of Lewis lung carcinoma (LLC) cells. Luteolin exhibited antiproliferative activity against LLC cells with IC50 of 12 microM. Luteolin effectively increased Annexin-V-positive cells as well as sub G1 DNA portion as seen on flow cytometric analysis. Western blotting has revealed that luteolin effectively activates caspase 9 and 3, cleaves poly (ADP-ribose) polymerase (PARP), and increases the ratio of Bax/Bcl-2. Furthermore, mitochondrial membrane potential was reduced by luteolin as seen on fluorescence microscopy. Luteolin downregulated the expression of extracellular signal-regulated kinase (ERK) and Akt in a concentration-dependent manner. In addition, luteolin significantly inhibited the growth of LLC cells implanted on the flank of mice to 40% and 60% of untreated control group values at 2 mg/kg and 10 mg/kg, respectively. Similarly, luteolin significantly reduced the expression of proliferating cell nuclear antigen (PCNA) as well as increased the expression of terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) in tumor section of LLC-bearing mice as determined by immunohistochemistry. Taken together, these results suggest that luteolin exerts antitumor activity by caspase activation and ERK/Akt inhibition.

In vivo effects of chronic contamination with depleted uranium on CYP3A and associated nuclear receptors PXR and CAR in the rat

In addition to its natural presence at high concentrations in some areas, uranium has several civilian and military applications that could cause contamination of human populations, mainly through chronic ingestion. Reports describe the accumulation of this radionuclide in some organs (including the bone, kidney, and liver) after acute or chronic contamination and show that it produces chemical or radiological toxicity or both. The literature is essentially devoid of information about uranium-related cellular and molecular effects on metabolic functions such as xenobiotic detoxification. The present study thus evaluated rats chronically exposed to depleted uranium in their drinking water (1mg/(ratday)) for 9 months. Our specific aim was to evaluate the hepatic and extrahepatic mRNA expression of CYP3A1/A2, CYP2B1, and CYP1A1 as well as of the nuclear receptors PXR, CAR, and RXR in these rats. CYP3A1 mRNA expression was significantly higher in the brain (200%), liver (300%), and kidneys (900%) of exposed rats compared with control rats, while CYP3A2 mRNA levels were higher in the lungs (300%) and liver (200%), and CYP2B1 mRNA expression in the kidneys (300%). Expression of CYP1A1 mRNA did not change significantly during this study. PXR mRNA levels increased in the brain (200%), liver (150%), and kidneys (200%). Uranium caused CAR mRNA expression in the lungs to double. Expression of RXR mRNA did not change significantly in the course of this study, nor did the hepatic activity of CYP2C, CYP3A, CYP2A, or CYP2B. Uranium probably affects the expression of drug-metabolizing CYP enzymes through the PXR and CAR nuclear receptors. These results suggest that the stimulating effect of uranium on these enzymes might lead to hepatic or extrahepatic toxicity (or both) during drug treatment and then affect the entire organism.

Differential inhibition of Scutellaria barbata D. Don (Lamiaceae) on HCG-promoted proliferation of cultured uterine leiomyomal and myometrial smooth muscle cells

Scutellaria barbata D. Don (Lamiaceae)(SB) is a perennial herb which is natively distributed throughout Korea and southern China. This herb is known in traditional Chinese Medicine as Ban-Zhi-Lian and traditional Korean medicine as Banjiryun, respectively. SB has been used as an anti-inflammatory and antitumor agent. We aimed to determine the expressin of cell cycle-related signal molecules for growth inhibition after HCG treatment by the herb SB in two different human myometrial smooth muscle cells (SMCs) and leiomyomal SMCs. Water-soluble ingredients of SB, myometrial SMCs and the leiomyomal cell lines were used in vitro. Uterine myomas often enlarge rapidly during pregnancy, implying that human chorionic gonadotrophin (HCG) may influences cell proliferation in uterine leiomyomata. We investigated the effects of SB on the cell proliferation and the expression of cell cycle-related proteins in these cells. Although HCG/LH receptor was present in both cultured myometrial and leiomyomal cells, as assayed by reverse transcription polymerase chain reaction analysis, treatment with HCG significantly increased cell proliferation in both myometrial and leiomyomal cells. However, SB reduced the proliferative effect of HCG in leiomyoma and myometrial cells, respectively. In HCG-treated leiomyomal cells, the expression of proliferating cell nuclear antigen, cyclin E and cdc2 was significantly reduced by SB treatment. These results suggest that SB reduced the HCG-promoted proliferation of myometrial and leiomyomal cells.

Methylene chloride fraction of Scutellaria barbata induces apoptosis in human U937 leukemia cells via the mitochondrial signaling pathway

BACKGROUND

Scutellaria barbata D.Don has been applied to treat cancers, inflammation and urinary disease. However, its antitumor mechanism still remains unclear.

METHODS

With methylene chloride fraction of Herba Scutellariae barbatae (MCSB), apoptosis-related experiments were carried out on human U937 leukemia cells by (a) 2,3-bis[2-4-nitro-5-sulphophenyl]2H-tetrazolium-5-carboxanilide (XTT) assay for cytotoxicity; (b) terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling (TUNEL) assay for morphological changes; (c) cell cycle analysis; (d) Western blot analysis of poly(ADP-ribose) polymerase (PARP), caspase-8, caspase-9, caspase-3 and Bax, Bcl-2 and cytochrome c expressions for apoptosis signaling pathway.

RESULTS

MCSB inhibited the proliferation of human U937 leukemia cells in a dose-dependent manner (IC50 = approximately 10 microg/ml). MCSB dose-dependently increased the sub-G1 DNA contents by cell cycle analysis. DNA fragments indicating induction of apoptosis were observed in MCSB-treated U937 cells by TUNEL assay. Caspase-9 and caspase-3 were activated while caspase-8 was intact by MCSB. Similarly, MCSB effectively cleaved PARP, increased the ratio of Bax/Bcl-2 and released the cytochrome c from mitochondria during apoptosis in U937 cells.

CONCLUSIONS

Our results suggest that MCSB can induce apoptosis via the mitochondria-mediated signaling pathway.

Inhibitory Effects ofScutellaria BarbataD. Don. andEuonymus Alatus Sieb. on Aromatase Activity of Human Leiomyomal Cells

It is now well documented that a large proportion of breast tumors express their own aromatase. This intratumoral aromatase produces estrogen in situ and therefore may contribute significantly to the amount of estrogen to which the cell is exposed. Thus it is not only important that aromatase inhibitors potently inhibit the peripheral production of estrogen and eliminate the external supply of estrogen to the tumor cell, but that they in addition potently inhibit intratumoral aromatase and prevent the tumor cell from making its own estrogen within the cell. To study the inhibition of intracellular aromatase, we have examined the aromatase-inhibiting potency of the Scutellaria barbata D. Don. (SB) and Euonymus alatus Sieb. (EA) in myometrial and leiomyomal cells which contain aromatase. We have also used human placental tissues. Although SB and EA are approximately equipotent in a cell-free aromatase system (human placental microsomes), EA is consistently 10-30 times more potent than SB in inhibiting intracellular aromatase in myometrial and leiomyomal cells. To provide insights into the effect of SB and EA on aromatase activity in leiomyomal cells, we examined the cell lines, which is induced to differentiate toward the more transformed cell phenotype by 12-tetradecanoylphorbal-13-acetate (TPA) as a protein kinase C activator and transforming growth factor-beta1 (TGF-beta1). Enzyme activity was inhibited in a time-and dose-dependent fashion by SB and EA and by either 1-50 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure.

Mechanisms of clinically relevant drug interactions associated with tacrolimus

The clinical management of tacrolimus, a macrolide used as immunosuppressant after transplantation, is complicated by its narrow therapeutic index in combination with inter- and intraindividually variable pharmacokinetics. As a substrate of cytochrome P450 (CYP) 3A enzymes and P-glycoprotein, tacrolimus interacts with several other drugs used in transplantation medicine, which also are known CYP3A and/or P-glycoprotein inhibitors and/or inducers. In clinical studies, CYP3A/P-glycoprotein inhibitors and inducers primarily affect oral bioavailability of tacrolimus rather than its clearance, indicating a key role of intestinal P-glycoprotein and CYP3A. There is an almost complete overlap between the reported clinical drug interactions of tacrolimus and those of cyclosporin. However, in comparison with cyclosporin, only few controlled drug interaction studies have been carried out, but tacrolimus drug interactions have been extensively studied in vitro. These results are inconsistent and are of poor predictive value for clinical drug interactions because of false negative results. P-glycoprotein regulates distribution of tacrolimus through the blood-brain barrier into the brain as well as distribution into lymphocytes. Interaction of other drugs with P-glycoprotein may change tacrolimus tissue distribution and modify its toxicity and immunosuppressive activity. There is evidence that ethnic and gender differences exist for tacrolimus drug interactions. Therapeutic drug monitoring to guide dosage adjustments of tacrolimus is an efficient tool to manage drug interactions. In the near future, progress can be expected from studies evaluating potential pharmacokinetic interactions caused by herbal preparations and food components, the exact biochemical mechanism underlying tacrolimus toxicity, and the potential of inhibition of CYP3A and P-glycoprotein to improve oral bioavailability and to decrease intraindividual variability of tacrolimus pharmacokinetics.

Immunomodulating activity of Chinese medicinal herbs and Oldenlandia diffusa in particular

The effect of eight different Chinese medicinal herbs (CMHs) on lymphocytes was studied in vitro using murine spleen cells. Among the studied eight CMHs, Astragalus membranaceus and Oldenlandia diffusa markedly stimulated murine spleen cells to proliferate. The responder cells for CMHs were B cells, because the response was depleted by the treatment of spleen cells with anti-immunoglobulin (i.g.) antibody and complement and after purification by nylon wool column. This response was not due to contamination by lipopolysaccharide (LPS), because CMHs could stimulate C3H/HeJ spleen cells which are low responders to LPS. CMHs enhanced the production of Ig. CMHs also enhanced the induction of allo-antigen specific cytotoxic T lymphocytes. However, CMHs had no effect on natural killer cells. Furthermore, CMHs stimulated macrophages to produce interleukin-6 and tumor necrosis factor. The electroelution of the proteins from SDS-PAGE gel showed that the active components of Oldenlandia diffusa had an apparent molecular weight of 90-200 kD and were sensitive to pronase E and NaIO4 treatment, suggesting glycoproteins in nature. These results suggest that CMHs have immunomodulating activity in vitro and this activity could be used clinically for the modulation of immune responses.

Oldenlandia diffusa and Scutellaria barbata augment macrophage oxidative burst and inhibit tumor growth

Oldenlandia diffusa (OD) and Scutellaria barbata (SB) have been used in traditional Chinese medicine for treating liver, lung and rectal tumors. In this study we determined the effects of these phytochemicals on oxidative burst as an indicator of phagocytic function in a murine macrophage cell line J774 using an automated micro-fluorometric assay. A dose-dependent augmentation of oxidative burst was observed with OD as well as SB. The effect of OD and SB on the growth of a murine renal cell carcinoma (Renca) was also determined. Balb/c mice were transplanted subcutaneously with 1 x 10(5) Renca cells and were randomized into groups of 10 to receive oral feeding of OD (4 mg/day), SB (4 mg/day), or saline as control. Oral feeding with either OD or SB significantly inhibited the growth of Renca in mice. The data of this study show that OD and SB are capable of enhancing macrophage function in vitro and inhibiting tumor growth in vivo.