Metabolism and pharmacokinetics of genipin and geniposide in rats

Geniposide, an iridoid glucoside, is a major constituent in the fruits of Gardenia jasminoides (Gardenia fruits), a popular Chinese herb. Genipin, the aglycone of geniposide, is used to prepare blue colorants in food industry and also a crosslinking reagent for biological tissue fixation. In this study, we investigated the metabolism and pharmacokinetics of genipin and geniposide in rats. Blood samples were withdrawn via cardiopuncture and the plasma samples were assayed by HPLC method before and after hydrolysis with sulfatase and beta-glucuronidase. The results indicated that after oral administration of genipin or Gardenia fruit decoction, genipin sulfate was a major metabolite in the bloodstream, whereas the parent forms of genipin and geniposide were not detected. Importantly, oral administration of 200mg/kg of genipin resulted in a mortality of 78% (7/9) in rats.     

Protective Effects of Geniposide and Genipin against Hepatic Ischemia/Reperfusion Injury in Mice

Geniposide is an active product extracted from the gardenia fruit, and is one of the most widely used herbal preparations for liver disorders. This study examined the cytoprotective properties of geniposide and its metabolite, genipin, against hepatic ischemia/reperfusion (I/R) injury. C57BL/6 mice were subjected to 60 min of ischemia followed by 6 h of reperfusion. Geniposide (100 mg/kg) and genipin (50 mg/kg) were administered orally 30 min before ischemia. In the I/R mice, the levels of serum alanine aminotransferase and hepatic lipid peroxidation were elevated, whereas hepatic glutathione/glutathione disulfide ratio was decreased. These changes were attenuated by geniposide and genipin administration. On the other hand, increased hepatic heme oxygenase-1 protein expression was potentiated by geniposide and genipin administration. The increased levels of tBid, cytochrome c protein expression and caspase-3 activity were attenuated by geniposide and genipin. Increased apoptotic cells in the I/R mice were also significantly reduced by geniposide and genipin treatment. Our results suggest that geniposide and genipin offer significant hepatoprotection against I/R injury by reducing oxidative stress and apoptosis.     

Preventive effect of geniposide on metabolic disease status in spontaneously obese type 2 diabetic mice and free fatty acid-treated HepG2 cells

Accumulation of visceral fat induces various symptoms of metabolic syndrome such as insulin resistance and abnormal glucose/lipid metabolism and eventually leads to the onset of ischemic cerebrovascular diseases. Geniposide, which is iridoid glycoside from the fruit of Gardenia jasminoides ELLIS, is recognized as being useful against hyperlipidemia and fatty liver. In order to clarify the effect of geniposide on metabolic disease-based visceral fat accumulation and the relevant molecular mechanism, experiments were performed in spontaneously obese Type 2 diabetic TSOD mice and the free fatty acid-treated HepG2 cells. In the TSOD mice, geniposide showed suppression of body weight and visceral fat accumulation, alleviation of abnormal lipid metabolism and suppression of intrahepatic lipid accumulation. In addition, geniposide alleviated abnormal glucose tolerance and hyperinsulinemia, suggesting that geniposide has an insulin resistance-alleviating effect. Next, in order to investigate the direct effect of geniposide on the liver, the effect on the free fatty acid-treated HepG2 fatty liver model was investigated using genipin, which is the aglycone portion of geniposide. Genipin suppressed the intracellular lipid accumulation caused by the free fatty acid treatment and also significantly increased the intracellular expression of a fatty acid oxidation-related gene (peroxisomal proliferator-activated receptor: PPARα). From these results, it was confirmed that geniposide has an anti-obesity effect, an insulin resistance-alleviating effect and an abnormal lipid metabolism-alleviating effect, and the metabolite genipin shows a direct effect on the liver, inducing expression of a lipid metabolism-related gene as one of its molecular mechanisms.     

Hepatotoxicity of geniposide in rats

The hepatotoxic effects of geniposide were investigated in rats. Increases in serum alanine aminotransferase and aspartate aminotransferase activities as a result of oral administration of 320 mg geniposide/kg body weight were suppressed when geniposide was administered ip or when the rats were pretreated with chloramphenicol. The non-protein sulphydryl content of the liver 4 hr after oral administration of geniposide decrease in a dose-dependent manner. Genipin, the aglycone of geniposide, had a marked reactivity with sulphydryl groups of glutathione and cysteine in vitro. The hepatotoxic effects of ip administration of genipin at a dose of 80 mg/kg body weight were comparable with those of oral administration of geniposide at a dose of 320 mg/kg. Buthionine sulphoximine pretreatment enhanced the toxicity of geniposide, while cysteine pretreatment completely suppressed it. These results suggest that the conversion of geniposide to genipin is causally related to the hepatotoxicity of geniposide and that hepatic non-protein sulphydryls are important in modulating the toxicity.     

Antithrombotic effect of geniposide and genipin in the mouse thrombosis model.

Geniposide is one of the constituents of Gardenia fruit (Gardenia jasminoides Ellis, Rubiaceae), which has been used in traditional medicine. Although its anti-inflammatory and antithrombotic effects have been reported, the way it acts is still unclear. We have investigated the effects of geniposide and its metabolite genipin on thrombogenesis and platelet aggregation. In an in vivo model, geniposide and genipin significantly (P < 0.05) prolonged the time required for thrombotic occlusion induced by photochemical reaction in the mouse femoral artery. In an in vitro study, both geniposide and genipin inhibited collagen-induced, but did not inhibit arachidonate-induced, mouse platelet aggregation. However aspirin, a cyclooxygenase inhibitor, inhibited arachidonate-induced platelet aggregation but only partially inhibited the collagen-induced one. We also showed, by measuring PLA(2)-catalyzed arachidonic acid release, that geniposide inhibited phospholipase A(2) (PLA(2)) activity. We conclude that geniposide showed an antithrombotic effect in vivo due to the suppression of platelet aggregation. PLA(2) inhibition by geniposide is one possible anti-platelet mechanism.     

Genotoxicity of gardenia yellow and its components.

Gardenia fruit (Gardenia jasminoides ELLIS) is widely used as a natural food colorant and as a traditional Chinese medicine for treatment of hepatic and inflammatory diseases. "Gardenia yellow" is a natural food colorant which is extracted by ethanol from gardenia fruit. The purpose of this study was to evaluate the genotoxicity of gardenia yellow. Genotoxicity of gardenia yellow and its components, crocetin, gentiobiose (a component of crocin), geniposide and genipin (formed by hydrolysis of geniposide), was studied by Ames test, rec-assay, and sister chromatid exchange (SCE) using V79 cells. Gardenia yellow and its components were found not to be mutagenic in the Salmonella reverse mutation assay. Gardenia yellow and genipin caused damage of DNA in rec-assay. Gardenia yellow induced a significant dose-dependent increase of SCE frequency (8.6 times at 1000 microg/ml as the value for the solvent control). Only genipin induced SCEs significantly among the components of gardenia yellow. Moreover, genipin induced a significant increase of tetraploids at all doses tested (95% at 8 microg/ml). Gardenia yellow preparation was analyzed by capillary electrophoresis (CE), and geniposide was detected. However, genipin was not observed. In conclusion, we have shown that genipin possesses genotoxicity. Furthermore, there were unidentified genotoxicants in gardenia yellow.     

A synopsis on flavonoids from the roots of Scutellaria baicalensis with some insights on baicalein and its anti-cancer properties

Flavones are the most dominant type of flavonoids isolated from the roots of Scutellaria baicalensis (Radix Scutellariae),which is a traditional medicinal plant in East Asian countries, including China, Japan and Korea. Most of the flavones are derivativeswith methoxyl and hydroxyl groups, and they include baicalein, baicalin, chrysin, norwogonin, oroxylin A and wogonin. Baicalein possesses anti-cancer activities against a wide spectrum of human cancer cells by inducing apoptosis and cell cycle arrest, and by inhibiting angiogenesis, metastasis and inflammation. Some examples of the effects of baicalein on apoptosis, cell cycle arrest and metastasis are presented with discussion on the molecular targets and pathways. Studies on the structure-activity relationships of flavonoid cytotoxicity towards human cancer cells show that the potent cytotoxic activities of baicalein can be attributed to its -OH groupsat C5, C6 and C7 (triple hydroxylation) of ring A, carbonyl group at C4 of ring C, and C2–C3 double bond of ring C.Studies on structural modifications of baicalein have shown that the configurations at C6 of ring A are critical factors influencing its anti-proliferative activity. Considering the remarkable anti-cancer properties, the future prospects for developing baicalein into an anti-cancer drug are promising.     

Secoiridoids and xanthones in the genus Centaurium

Two new acyl secoiridoid glucosides, named decentapicrins A and B, accumulating in the fruits of CENTAURIUM LITTORALE G ILMOUR spp. LITTORALE, have been isolated by means of preparative column chromatography. Another new compound, named decentapicrin C, could also be detected but in minute amounts and was prepared from decentapicrin B. The close interrelation between these three compounds and the strongly bitter centapicrin (Ia) and desacetylcentapicrin (Ib), accumulating in the fruits of CENTAURIUM ERYTHRAEA R AFN. [1, 2], have been demonstrated by means of TLC analysis of the products obtained under alkaline treatment. Under these conditions not only hydrolysis, but also acyl migrations, took place. Decentapicrin A is partly converted into desacetylcentapicrin (Ib) and decentapicrin C; decentapicrin B is converted into decentapicrin C. On the basis of this chemical information and spectroscopical data ( (1)H-NMR, (13)C-NMR, UV and IR) the structures of decentapicrins A, B and C are postulated to be Ic, Id and Ie respectively. The single acylation at C (3)-OH and C (4)-OH of the glucose moiety as shown in the structures of decentapicrins A and B is new in iridoid chemistry. Unlike centapicrin (Ia) and desacetylcentapicrin (Ib) the new compounds decentapicrins A, B and C are only weak bitter principles like sweroside (I).     

Two new iridoid glucosides from Picrorhiza scrophulariiflora

Two new iridoid glucosides with 3,4-dihydrocatalpol skeleton, piscrosides A (1) and B (2) together with nine known iridoid glucosides and three known cucurbitacin glucosides, were isolated from the stems of Picrorhiza scrophulariiflora. Their structures were established by MS, ¹H NMR, ¹³C NMR and 2D NMR methods (including HSQC, HMBC and NOESY experiments).     

LC-MS/MS同时测定犬干血浆样品中栀子苷、山栀苷及京尼平龙胆双糖苷的浓度

目的：建立LC-MS/MS法同时测定犬干血浆样品中栀子苷、山栀苷及京尼平龙胆双糖苷浓度的分析方法,并应用于犬药代动力学研究中。方法：采用Ecosil C18 （4.6 mm×150 mm,5 μm）色谱柱,流动相为甲醇-20 mmol/L 甲酸铵（0.1%甲酸）,梯度洗脱;使用电喷雾离子源（ESI）,正离子多反应监测模式检测。应用干血浆采样技术收集犬静脉输注栀子提取液后的血浆样品,超声提取后进行LC-MS/MS分析。结果： 3种环烯醚萜苷类成分在线性范围内的相关性良好（r〉0.99）,日内、日间变异均〈15%,绝对回收率在 79.9%~91.4%之间,4 ℃ 放置和室温放置 24 h、75 d 稳定性良好。药代动力学参数显示栀子苷、山栀苷、京尼平龙胆双糖苷的t1/2分别为 6.86、0.687、2.11 h,AUC0→t分别为158、9.16、34.0 μg·mL^-1·h。结论：建立的同时检测干血浆样品中栀子苷、山栀苷、京尼平龙胆双糖苷浓度的液相色谱-串联质谱分析法,灵敏度好、专属性强。干血浆样品室温放置稳定性好,易于储存运输,适用于药代动力学研究中。     

Role of metabolism by human intestinal microflora in geniposide-induced toxicity in HepG2 cells

Possible role of metabolism by the intestinal bacteria in geniposide-induced cytotoxicity was investigated in human hepatoma HepG2 cells. Initially, toxic effects of geniposide and its metabolite genipin were compared. Genipin, a deglycosylated form of geniposide, was cytotoxic at the concentrations that geniposide was not. As metabolic activation systems for geniposide, human intestinal bacterial cultures, fecal preparation (fecalase) and intestinal microbial enzyme mix were employed in the present study. When geniposide was incubated with human intestinal bacteria, either Bifidobacterium longum HY8001 or Bacteroides fragilis, for 24 h, the cultured media caused cytotoxicity in HepG2 cells. Fecalase and intestinal enzyme mix were also effective to metabolically activate geniposide to its cytotoxic metabolite. The present results indicated that genipin, a metabolite of geniposide, might be more toxic than geniposide, and that intestinal bacteria might have a role in biotransformation of geniposide to its toxic metabolite. In addition, among three activation systems tested, intestinal microbial enzyme mix would be convenient to use in detecting toxicants requiring metabolic activation by intestinal bacteria.     

Further flavonol and iridoid glycosides from Ajuga remota aerial parts

Five new iridoid glycosides characterised as 6-keto-8-acetylharpagide (1), 6,7-dehydro-8-acetylharpagide (2), 7,8-dehydroharpagide (3), 8-acetylharpagide-6-O-β-glucoside (4), harpagide-6-O-β-glucoside (5) together with three flavonol glycosides, myricetin 3-O-rutinoside-4'-O-rutinoside (6), myricetin 3-O-rutinoside-3'-O-rutinoside (7) and isorhamnetin 3-O-rutinoside-7-O-rutinoside-4'-O-β-glucoside (8) have been isolated from the aerial parts of Ajuga remota. Also isolated were two known compounds ajugarin IV and ajugarin V. Their structures were established using spectroscopic methods including UV, IR, FAB-MS, HR-MS, 1D and 2D NMR techniques.     

山萸肉炮制前后4种环烯醚萜苷类成分的含量变化研究

目的:研究山萸肉炮制前后4种环烯醚萜苷类成分的含量变化情况。方法:以同一种山萸肉为原料,分别依法炮制,制成酒蒸、酒炖、加压酒蒸萸肉,再采用高效液相色谱法测定各样品中4种环烯醚萜苷类成分的含量。色谱柱为Waters sunfire C18(250mm×4.6 mm,5μm),流动相为甲醇-水(梯度洗脱),柱温为(30±1)℃,流速为0.8 ml/min,进样量为10μl,莫诺苷、獐牙菜苷、马钱苷和山茱萸新苷的检测波长分别为240、246、237、219 nm。结果:炮制前,莫诺苷、獐牙菜苷、马钱苷和山茱萸新苷在山萸肉中的含量分别为10.66、0.56、4.90、1.48 mg/g,但炮制后4种成分均有不同程度的下降,其中酒炖萸肉中莫诺苷、獐牙菜苷和马钱苷的含量最低,加压酒蒸萸肉中山茱萸新苷的含量最低。结论:山萸肉炮制后4种环烯醚萜苷类成分的含量均有下降。     

Effect of geniposide,a hypoglycemic glucoside,on hepatic regulating enzymes in diabetic mice induced by a high-fat diet and streptozotocin

Aim:

Hepatic glycogen phosphorylase (GP) and glucose-6-phosphatase (G6Pase) play an important role in the control of blood glucose homeostasis and are proposed to be potential targets for anti-diabetic drugs. Geniposide is an iridoid glucoside extracted from Gardenia jasminoides Ellis fruits and has been reported to have a hypoglycemic effect. However, little is known about the biochemical mechanisms by which geniposide regulates hepatic glucose-metabolizing enzymes. The present study investigates whether the hypoglycemic effect of geniposide is mediated by GP or G6Pase.

Methods:

Type 2 diabetic mice, induced by a high-fat diet and streptozotocin injection, were treated with or without geniposide for 2 weeks. Blood glucose levels were monitored by a glucometer. Insulin concentrations were analyzed by the ELISA method. Total cholesterol (TC) and triglyceride (TG) levels were measured using Labassay™ kits. Activities of hepatic GP and G6Pase were measured by glucose-6-phosphate dehydrogenase-coupled reaction. Real-time RT-PCR and Western blotting were used to determine the mRNA and protein levels of both enzymes.

Results:

Geniposide (200 and 400 mg/kg) significantly decreased the blood glucose, insulin and TG levels in diabetic mice in a dose-dependent manner. This compound also decreased the expression of GP and G6Pase at mRNA and immunoreactive protein levels, as well as enzyme activity.

Conclusion:

Geniposide is an effective hypoglycemic agent in diabetic mice. The hypoglycemic effect of this compound may be mediated, at least in part, by inhibiting the GP and G6Pase activities.     

Administration of geniposide ameliorates dextran sulfate sodium-induced colitis in mice via inhibition of inflammation and mucosal damage

Ulcerative colitis (UC), an idiopathic inflammatory bowel disease, not only affects millions of patients worldwide, but also increases the risk of colon cancer. Geniposide is an iridoid glycoside and has many biological activities such as anti-inflammatory and antioxidant. However, its protective efficacy and mechanism of action against UC are still unclear. In this study, we aimed to investigate the protective effects and mechanisms of geniposide on dextran sulfate sodium (DSS)-induced experimental colitis in mice. The results revealed that geniposide alleviated body weight loss, disease activity index, colon length shortening and colonic pathological damage induced by DSS. Geniposide significantly suppressed pro-inflammatory cytokines by regulating NF-κB and PPARγ pathways in vivo and in vitro. Furthermore, geniposide also significantly regulated the expressions of ZO-1 and occludin in DSS-induced experimental colitis in mice and lipopolysaccharide (LPS)-triggered inflammation in Caco-2 cells. These findings indicated that geniposide may be a new natural chemopreventive agent to combat UC.     

Hepatotoxicity of gardenia yellow color in rats

Acute toxicity by gardenia yellow color was studied in rats. Oral administration of the colorant at doses of 800 mg/kg up to 5000 mg/kg caused diarrhea and increases in serum alanine aminotransferase and aspartate aminotransferase activities in a dose-dependent manner. After 24 h of oral treatment with 2000 mg/kg of the colorant, liver showed partially hemorrhagic changes and the intestinal tract, especially the duodenum, appeared blue. The toxicity induced by the colorant was stronger by oral administration than by intraperitoneal administration. The content of geniposide, an iridoid compound, was estimated to be 28% of the colorant, and this iridoid accounted for almost all the hepatotoxic activity of the colorant.     

环烯醚萜类化合物近年研究进展

目的 介绍环烯醚萜类化合物研究概况和近年研究进展。方法 以近年来国内外发表的文献为依据,从结构分类、半合成及生物活性方面综述环烯醚萜类化合物近年研究进展。结果 环烯醚萜类化合物具有多种生物活性。结论 环烯醚萜是一类很有研究价值的化合物。     

Genipin-induced apoptosis in hepatoma cells is mediated by reactive oxygen species/c-Jun NH2-terminal kinase-dependent activation of mitochondrial pathway

Genipin, the aglycone of geniposide, exhibits anti-inflammatory and anti-angiogenic activities. Here we demonstrate that genipin induces apoptotic cell death in FaO rat hepatoma cells and human hepatocarcinoma Hep3B cells, detected by morphological cellular changes, caspase activation and release of cytochrome c. During genipin-induced apoptosis, reactive oxygen species (ROS) level was elevated, and N-acetyl-l-cysteine (NAC) and glutathione (GSH) suppressed activation of caspase-3, -7 and -9. Stress-activated protein kinase/c-Jun NH2-terminal kinase 1/2(SAPK/JNK1/2) but neither MEK1/2 nor p38 MAPK was activated in genipin-treated hepatoma cells. SP600125, an SAPK/JNK1/2 inhibitor, markedly suppressed apoptotic cell death in the genipin-treated cells. The FaO cells stably transfected with a dominant-negative c-Jun, TAM67, was less susceptible to apoptotic cell death triggered by genipin. Diphenyleneiodonium (DPI), an inhibitor of NADPH oxidase, inhibited ROS generation, apoptotic cell death, caspase-3 activation and JNK activation. Consistently, the stable expression of Nox1-C, a C-terminal region of Nox1 unable to generate ROS, blocked the formation of TUNEL-positive apoptotic cells, and activation of caspase-3 and JNK in FaO cells treated with genipin. Our observations imply that genipin signaling to apoptosis of hepatoma cells is mediated via NADPH oxidase-dependent generation of ROS, which leads to downstream of JNK.     

Metabolic activities of ginsenoside Rb1, baicalin, glycyrrhizin and geniposide to their bioactive compounds by human intestinal microflora

To evaluate the pharmacological actions of herbal medicines, metabolic activities of herbal medicine components, ginsenoside Rb1, glycyrrhizin, geniposide and baicalin to their bioactive compounds compound K, 18beta-glycyrrhetic acid, genipin and baicalein by fecal specimens were measured. Their metabolic activities were 646.1+/-591.4, 29.4+/-51.7, 926.3+/-569.6 and 3884.6+/-1400.1 micromol/h/g, respectively. The profiles of these metabolic activities of baicalin and ginsenoside Rb1 were not significantly different to those of water extracts of Scutellariae Radix and Ginseng Radix. None of the metabolic activities tested were different between males and females, or between ages. However, the difference in these metabolic activities in individuals was significant. These results suggest that the human intestinal microflora enzymes that convert herbal components to their bioactive compounds may be used as selection markers of responders to traditional medicines.