Modulatory influence of Andrographis paniculata on mouse hepatic and extrahepatic carcinogen metabolizing enzymes and antioxidant status

The effects of two doses (50 and 100 mg/kg body wt/day for 14 days) of an 80% hydroalcohol extract of Andrographis paniculata and butylated hydroxyanisole (BHA) were examined on drug metabolizing enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase (LDH) and lipid peroxidation in the liver of Swiss albino mice (6-8 weeks old). The effect of the extract and BHA were also examined on lung, kidney and forestomach for the activities of glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD) and catalase. A significant increase in the levels of acid soluble sulphydryl (-SH) content, cytochrome P450, cytochrome P450 reductase, cytochrome b5 reductase, GST, DTD and SOD were observed at both dose levels of extract treatment while catalase, glutathione peroxidase and glutathione reductase (GR) showed significant increases only at the higher dose in the liver. Both Andrographis treated groups showed a significant decrease in activity of LDH and malondialdehyde (MDA) formation. BHA treated mice showed a significant increase in the levels of cytochrome b(5), GST, DTD, -SH content, GR and catalase in liver; while LDH and MDA levels were reduced significantly compared with their control values. In the lung, SOD, catalase and DTD, in the kidney catalase, DTD and GST, and in the forestomach SOD and DTD showed a significant increase at both dose levels of treatment. In BHA treated mice GST, DTD and catalase were significantly induced in the lung and along with these enzymes SOD was also induced in the kidney. In the case of the forestomach of BHA treated mice GST, DTD and SOD were enhanced significantly. These findings indicate the chemopreventive potential of Andrographis paniculata against chemotoxicity including carcinogenicity.     

Differential inhibition of rat and human hepatic cytochrome P450 by Andrographis paniculata extract and andrographolide

The inhibitory effect of Andrographis paniculata extract (APE) and andrographolide (AND), the most medicinally active phytochemical in the extract, on hepatic cytochrome P450s (CYPs) activities was examined using rat and human liver microsomes. For this purpose, CYP1A2-dependent ethoxyresorufin-O-deethylation, CYP2B1-dependent benzyloxyresorufin-O-dealkylation, CYP2B6-dependent bupropion hydroxylation, CYP2C-dependent tolbutamide hydroxylation, CYP2E1-dependent p-nitrophenol hydroxylation and CYP3A-dependent testosterone 6 beta-hydroxylation activities, were determined in the presence and absence of APE or AND (0-200 microM). APE inhibited ethoxyresorufin-O-deethylation activity in rat and human liver microsomes, with apparent Ki values of 8.85 and 24.46 microM, respectively. In each case, the mode of inhibition was noncompetitive. APE also inhibited tolbutamide hydroxylation both in rat and human microsomes with apparent Ki values of 8.21 and 7.51 microM, respectively and the mode of inhibition was mixed type. In addition, APE showed a competitive inhibition only on CYP3A4 in human microsomes with Ki of 25.43 microM. AND was found to be a weak inhibitor of rat CYP2E1 with a Ki of 61.1 microM but did not affect human CYP2E1. In conclusion, it cannot be excluded from the present study that APE could cause drug-drug interactions in humans through CYP3A and 2C9 inhibition.     

菊花提取物对大鼠肝微粒体细胞色素P450的影响

目的：观察菊花提取物对大鼠肝微粒体细胞色素P450及其同工酶的影响。方法：大鼠分别灌服给予相当于生药量10g／kg、2g／kg菊花提取物，连续15天，用超速离心法制备肝微粒体，用紫外分光光度法测定细胞色素P450及其同工酶的活性。结果：给药组的P450酶水平和二甲基亚硝胺(NDMA)脱甲基酶活性明显降低，而红霉素脱甲基酶的活性没有明显变化。结论：菊花提取物对大鼠肝细胞色素P450有明显抑制作用，并具有一定的亚族选择性。     

Effect of the water extract and ethanol extract from traditional Chinese medicines Angelica sinensis (Oliv.) Diels, Ligusticum chuanxiong Hort. and Rheum palmatum L. on rat liver cytochrome P450 activity

Angelica sinensis (Oliv.) Diels (DG), Ligusticum chuanxiong Hort. (CX) and Rheum palmatum L. (DH), three well known traditional Chinese medicines (TCM), have been used widely for the treatment of various types of disorders in China. Herb-drug interactions, especially cytochrome P450 (CYP)-mediated interactions, cause an enhancement or attenuation in the efficacy of co-administered drugs. In this study, to assess the possible interactions between TCM and drugs, the effect of water and ethanol extracts of DG, CX and DH on cytochrome P450 were studied in rats. The activities of various CYP enzymes were determined by HPLC method. Treatment of rats with water extracts or ethanol extracts of DG, CX and DH at daily dosages equivalent to 3 g (dry herbal material)/kg all increased the microsome protein contents and decreased the total CYP levels. The water extract of DG strongly increased the activities of CYP2D6 and 3A and the water extract of DH significantly increased the activity of 2D6. The other water extracts all showed inhibition against CYP isoforms. Only the ethanol extract of DG and DH increased the CYP2D6 and 3A activities, respectively, and the other ethanol extracts all decreased the level of CYP isoforms. All extract treatments had significant effects on CYP isoforms activities, whether induction or inhibition, compared with the blank control. Thus, caution should be paid to possible drug interactions of DG, CX, DH and CYP substrates.     

枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响

目的：观察枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响。方法：大鼠分别灌胃给予枳椇子醋酸乙酯提取物相当于生药量0.14,0.17,0.2 g·kg^-1,连续10 d,采用紫外分光光度法测定细胞色素P450与NADPH-细胞色素C(P-450)还原酶含量及苯胺羟化酶(ANH)、氨基比林N-脱甲基酶(ADM)、红霉素N-脱甲基酶(ERD)的活性。采用RT-PCR技术检测大鼠肝脏CYP1A1,CYP2C11,CYP2E1,CYP3A1基因的水平。结果：枳椇子醋酸乙酯提取物对细胞色素P450及NADPH-细胞色素C(P-450)还原酶含量无显著影响；可抑制苯胺羟化酶(ANH)活性,抑制率可达31.5%；可增加氨基比林N-脱甲基酶(ADM)活性,可达42.4%；而对红霉素N-脱甲基酶(ERD)的活性没有明显变化。在mRNA水平上,CYP2E1基因的表达水平没有变化；CYP1A1,CYP2C11和CYP3A1基因表达水平则明显增加。结论：枳椇子醋酸乙酯提取物对大鼠肝P450同工酶的影响表现出特异性,对不同的P450同工酶作用不同。     

Inhibitory effect of some herbal extracts on adherence of Streptococcus mutans

The objective of this study was to investigate the inhibitory effect of the crude extracts from some herbs on adherence of Streptococcus mutans (S. mutans) ATCC 25175 and TPF-1 in vitro. Six herbs, Andrographis paniculata; Cassia alata; Chinese black tea (Camellia sinensis); guava (Psidium guajava); Harrisonia perforata and Streblus asper, were extracted with 50 or 95% ethanol and dried. Herbal extracted solution at 0.5% concentration (w/v) was initially tested for bacterial adherence on glass surfaces. In order to identify type and effective concentration of the extracts, the extracts that showed the inhibition on glass surfaces were then tested on saliva-coated hydroxyapatite by the use of radiolabeled bacteria. To study the mechanism of action, the effect of the extracts at such concentration on glucosyltransferase and glucan-binding lectin activities were examined. It was found that all extracts, but Streblus asper, showed significant inhibitory effect on bacterial adherence to glass surfaces. For the saliva-coated hydroxyapatite adherence assay, Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175. Chinese black tea was the strongest inhibitor followed by Andrographis paniculata, Cassia alata and Harrisonia perforata, respectively. For S. mutans TPF-1, adherence inhibition was observed from Andrographis paniculata and Cassia alata at similar levels. The lowest concentrations of the extracts that inhibited the adherence at least 50% were 0.5% of Andrographis paniculata, 0.5% of Cassia alata, 0.3% of Chinese black tea and 0.5% of Harrisonia perforata for S. mutans ATCC 25175. For S. mutans TPF-1, the effective concentrations were 0.5% of Andrographis paniculata and 0.4% of Cassia alata. All extracts at such concentrations decreased the activity of glucosyltransferase from both strains. Only Andrographis paniculata and Cassia alata eliminated or decreased the activity of glucan-binding lectin from both strains. These findings suggested that Andrographis paniculata, Cassia alata, Chinese black tea and Harrisonia perforata could inhibit adherence of S. mutans ATCC 25175, while Andrographis paniculata and Cassia alata had an effect on S. mutans TPF-1 in vitro at the concentrations employed in this study.     

The influence of Sutherlandia frutescens on adrenal steroidogenic cytochrome P450 enzymes

AIM OF THE STUDY: The aim of this study was to investigate whether Sutherlandia frutescens, subsp. microphylla (family: Fabaceae/Leguminosa), which is traditionally used to treat symptoms of chronic stress generally associated with increased circulating glucocorticoids, influences the biosynthesis of these glucocorticoids. METHODS: We investigated the interaction of Sutherlandia frutescens with cytochrome P450 enzymes, CYP17 and CYP21, which catalyse key reactions in glucocorticoid biosynthesis. The binding of progesterone and pregnenolone to these enzymes and their metabolism were assayed in the presence of extracts and the bioactive compounds, l-canavanine, pinitol, GABA, flavonoids and triterpenoid glucosides present in the shrub. RESULTS: While the aqueous and methanol extracts inhibited the type I progesterone-induced difference spectrum (p<0.05), inhibition of pregnenolone binding (p=0.25) was negligible, with the aqueous extract exhibiting greater inhibition. The triterpenoid fraction inhibited both the type I pregnenolone- and progesterone-induced difference spectra and elicited a type II difference spectrum in the absence of substrate. Both pregnenolone and progesterone metabolism were inhibited by the aqueous extract, the inhibition of CYP21 being greater than that of CYP17, influencing the flux through glucocorticoid precursor pathways. CONCLUSION: This attenuation of adrenal P450 enzymes may thus demonstrate a possible mechanism by which Sutherlandia frutescens reduces glucocorticoid levels and alleviates symptoms associated with stress.     

Anticancer and immunostimulatory compounds from Andrographis paniculata

Andrographis paniculata extract is traditionally used as a medicine to treat different diseases in India, China and Southeast Asia. In the present study, we evaluated the anticancer and immunomodulatory activity of the methanolic extract of Andrographis paniculata in human cancer and immune cells. The methanolic extract of Andrographis paniculata was fractionated into dichloromethane, petroleum ether and aqueous extracts and screened for bioactivity. Our results indicate that the dichloromethane fraction of the methanolic extract retains the active compounds contributing for both the anticancer and immunostimulatory activity. Dichloromethane fraction significantly inhibits the proliferation of HT-29 (colon cancer) cells and augments the proliferation human peripheral blood lymphocytes (HPBLs) at low concentrations. On further fractionation of the dichloromethane extract we could isolate three diterpene compounds, i.e. [1] andrographolide, [2] 14-deoxyandrographolide and [3] 14-deoxy-11,12-didehydroandrographolide. Andrographolide showed anticancer activity on diverse cancer cells representing different types of human cancers. Whereas all the three molecules showed enhanced proliferation and interleukin-2 (IL-2) induction in HPBLs.     

决明子水提液对大鼠肝脏CYP450酶的影响

该文研究决明子水提液对大鼠肝脏CYP450酶酶活性、mRNA及蛋白表达水平的影响。取SD大鼠,口服灌胃受试药物后,处死,用冰冷生理盐水灌流肝脏,提取大鼠肝脏微粒体、肝脏总RNA和总蛋白,采用Cocktail体外孵育法结合液质联用(LCMS)技术对大鼠肝脏中CYP1A2,2B1,2C11,2D2,2E1,3A1各亚酶的酶活性进行测定,并应用荧光定量PCR技术和Western blot对上述亚型的mRNA和蛋白表达水平进行检测。结果表明,酶活性方面,决明子水提液组与空白组比较可明显诱导CYP1A2,2B1,2C11,2D2,2E1,3A1的酶活性,其中决明子低剂量组对CYP2D2有明显的抑制作用,中、高剂量组对CYP2D2有明显的诱导作用,且都呈剂量依赖性增加,但对CYP3A1的诱导不呈剂量依赖性;mRNA表达方面,决明子水提液对CYP1A2,2C11,2D2,2E1mRNA的表达具有显著诱导作用,其中对CYP1A2,2D2,2E1诱导作用呈剂量依赖性,与酶活性水平具有一致性,对CYP2B1,3A1没有明显作用;蛋白表达方面,决明子水提液对CYP2C11,2E1的表达也具有诱导作用,但没有统计学差异。决明子水提液对CYP450同工酶不同程度诱导或抑制作用,特别是对于CYP2C11,2E1亚型酶,酶活性与mRNA,蛋白表达水平具有一致性,提示当与这些酶底物合并用药时,尤其是与CYP2C11,2E1代谢有关的药物合用时,应充分考虑到潜在的有益和不利的药物相互作用。