Cantharidin analogue alleviates dextran sulfate sodium-induced colitis in mice by inhibiting the activation of NF-κB signaling.

Ulcerative colitis is a chronic inflammatory disease with a remitting-relapsing clinical course, it has evolved into a global burden given its high incidence worldwide. Cantharidin (CTD) derivatives are a class of compounds whose structures characterized with a 7-oxabicyclo [2.2.1]heptane core. Though potent cytotoxicity CTD and its derivatives showed, their clinical usage as anti-cancer drugs was limited by the toxicity in organs. In order to find new CTD analogues with good activity and lower toxicity, 21 CTD analogues with or without alkynyl substitution at C5 position of 7-oxabicyclo [2.2.1]heptane core were synthesized, some compounds showed better in vitro anti-inflammatory activity compared to CTD and norcantharidin (NCTD). Based on the structure-activity relationship results of in vitro experiment, analogue 3i was chosen for further study. Results from the acute toxicity in mice showed that 3i was hypotoxic with the single-dose MTD (maximum tolerated dose) for oral administration is over 1852 mg/kg, at least 35-fold lower than that of NCTD. Mechanism study indicated that 3i could potently inhibit TNF-α induced activation of NF-κB signaling by down-regulation the expression levels of phosphor- IKK, IκBα, and NF-κB p65, and alleviated dextran sulfate sodium-induced colitis in mice. This study indicated that CTD analogues with alkynyl substitution at C5 position of 7-oxabicyclo [2.2.1]heptane core is a kind of new compounds with good anti-inflammatory activity and lower toxicity in vivo, and might be used as therapeutic agents for inflammatory diseases.

Cell death mechanisms induced by synergistic effects of halofuginone and artemisinin in colorectal cancer cells.

Our previous study found that the combination of halofuginone (HF) and artemisinin (ATS) synergistically arrest colorectal cancer (CRC) cells at the G1/G0 phase of the cell cycle; however, it remains unclear whether HF-ATS induces cell death. Here we report that HF-ATS synergistically induced caspase-dependent apoptosis in CRC cells. Specifically, both in vitro and in vivo experiments showed that HF or HF-ATS induces apoptosis via activation of caspase-9 and caspase-8 while only caspase-9 is involved in ATS-induced apoptosis. Furthermore, we found HF or HF-ATS induces autophagy; ATS can't induce autophagy until caspase-9 is blocked. Further analyzing the crosstalk between autophagic and caspase activation in CRC cells, we found autophagy is essential for activation of caspase-8, and ATS switches to activate capase-8 via induction of autophagy when caspase-9 is inhibited. When apoptosis is totally blocked, HF-ATS switches to induce autophagic cell death. This scenario was then confirmed in studies of chemoresistance CRC cells with defective apoptosis. Our results indicate that HF-ATS induces cell death via interaction between apoptosis and autophagy in CRC cells. These results highlight the value of continued investigation into the potential use of this combination in cancer therapy.

The Exploration of Novel Pharmacophore Characteristics and Multidirectional Elucidation of Structure-Activity Relationship and Mechanism of Sesquiterpene Pyridine Alkaloids from Tripterygium Based on Computational Approaches.

Sesquiterpene pyridine alkaloids are a large group of highly oxygenated sesquiterpenoids, which are characterized by a macrocyclic dilactone skeleton containing 2-(carboxyalkyl) nicotinic acid and dihydro-ß-agarofuran sesquiterpenoid, and are believed to be the active and less toxic components of Tripterygium. In this study, 55 sesquiterpene pyridine alkaloids from Tripterygium were subjected to identification of pharmacophore characteristics and potential targets analysis. Our results revealed that the greatest structural difference of these compounds was in the pyridine ring and the pharmacophore model-5 (Pm-05) was the best model that consisted of three features including hydrogen bond acceptor (HBA), hydrogen bond donor (HBD), and hydrophobic (HY), especially hydrophobic group located in the pyridine ring. It was proposed that 2-(carboxyalkyl) nicotinic acid part possessing a pyridine ring system was not only a pharmacologically active center but also a core of structural diversity of alkaloids from Tripterygium wilfordii. Furthermore, sesquiterpene pyridine alkaloids from Tripterygium were predicted to target multiple proteins and pathways and possibly played essential roles in the cure of Alzheimer's disease, breast cancer, Chagas disease, and nonalcoholic fatty liver disease (NAFLD). They also had other pharmacological effects, depending on the binding interactions between pyridine rings of these compounds and active cavities of the target genes platelet-activating factor receptor (PTAFR), cannabinoid receptor 1 (CNR1), cannabinoid receptor 1 (CNR2), squalene synthase (FDFT1), and heat shock protein HSP 90-alpha (HSP90AA1). Taken together, the results of this present study indicated that sesquiterpene pyridine alkaloids from Tripterygium are promising candidates that exhibit potential for development as medicine sources and need to be promoted.

Optimization extraction, structural features and antitumor activity of polysaccharides from Z. jujuba cv. Ruoqiangzao seeds.

As a discarded byproduct of jujube (Z. jujuba), its seeds contain various biological components. Response surface methodology was used to optimize ultrasound-assisted heating extraction conditions of polysaccharides from Z. jujuba cv. Ruoqiangzao seeds (ZJSPs). The optimal parameters were as follows: temperature 83.1 °C, time 100 min, ultrasonic power 140 W, and water-material ratio 33.5 mL/g, allowed a maximum yield of 1.97%. One main fraction (ZJSPs-1) was successfully purified by ion-exchange and gel-permeation chromatography. With a molecular weight of 342 kDa, ZJSPs-1 was composed of arabinose, glucose, xylose, galactose and rhamnose. The presence of pyranose-form sugars as well as both α- and ß-configurations was validated by FT-IR and 1H NMR. TG/DSC indicated that ZJSPs-1 has a favorable thermal stability. XRD suggested that ZJSPs-1 exhibited both crystalline and amorphous portions. ZJSPs-1 was in aggregates of homogenous-dense honeycomb like structures observed by SEM and AFM. ZJSPs-1 possessed antitumor activities against HeLa cells in a dose- and time-dependent manner at 24 and 48 h with IC50 of 164.6 and 87.1 µg/mL, respectively. Fluorescent microscopic and flow cytometry revealed that ZJSPs-1 inhibited the proliferation of HeLa cells through apoptosis. Z. jujuba seeds are good sources for antitumor polysaccharides in pharmaceutical and food industries.

Paeoniflorin exerts neuroprotective effects by modulating the M1/M2 subset polarization of microglia/macrophages in the hippocampal CA1 region of vascular dementia rats via cannabinoid receptor 2.

BACKGROUND: Cerebral hypoperfusion is a pivotal risk factor for vascular dementia (VD), for which effective therapy remains inadequate. Persistent inflammatory responses and excessive chemotaxis of microglia/macrophages in the brain may accelerate the progression of VD. Endocannabinoids are involved in neuronal protection against inflammation-induced neuronal injury. Cannabinoids acting at cannabinoid receptor 2 (CB2R) can decrease inflammation. Based on the identification of paeoniflorin (PF) as a CB2R agonist, we investigated the neuroprotective and microglia/macrophages M1 to M2 polarization promoting effects of PF in a permanent four-vessel occlusion rat model. METHODS: One week after surgery, PF was intraperitoneally administered at a dose of 40 mg/kg once a day for 28 successive days. The effects of PF on memory deficit were investigated by a Morris water maze test, and the effects of PF on hippocampal neuronal damage were evaluated by light microscope and electron microscope. The mRNA and protein expression levels of key molecules related to the M1/M2 polarization of microglia/macrophages were assessed by RT-qPCR and Western blotting, respectively. RESULTS: Administration of PF could significantly attenuate cerebral hypoperfusion-induced impairment of learning and memory and reduce the morphological and ultrastructural changes in the hippocampal CA1 region of rats. Moreover, PF promoted an M1 to M2 phenotype transition in microglia/macrophages in the hippocampus of rats. In addition to its inhibitory property against proinflammatory M1 mediator expression, such as IL-1ß, IL-6, TNF-α and NO, PF dramatically up-regulated expression of anti-inflammatory cytokines IL-10 and TGF-ß1. Importantly, CB2R antagonist AM630 abolished these beneficial effects produced by PF on learning, memory and hippocampus structure in rats, as well as the polarization of microglia/macrophages to the M2 phenotype. Additionally, PF treatment significantly inhibited cerebral hypoperfusion-induced mTOR/NF-κB proinflammatory pathway and enhanced PI3K/Akt anti-inflammatory pathway. Effects of PF on these signaling pathways were effectively attenuated when rats were co-treated with PF and AM630, indicating that the mTOR/NF-κB and PI3K/Akt signaling pathways were involved in the PF effects through CB2R activation. CONCLUSION: These findings demonstrated PF exerts its neuroprotective effect and shifts the inflammatory milieu toward resolution by modulation of microglia/macrophage polarization via CB2R activation.

Ginsenoside 20(S)-Rh2 Induces Apoptosis and Differentiation of Acute Myeloid Leukemia Cells: Role of Orphan Nuclear Receptor Nur77.

Ginsenoside 20(S)-Rh2 has been shown to induce apoptosis and differentiation of acute myeloid leukemia (AML) cells. However, the underlying molecular mechanisms are not fully understood. In our study, 20(S)-Rh2 induced the expression of orphan nuclear receptor Nur77 and death receptor proteins Fas, FasL, DR5, and TRAIL, as well as the cleavage of caspase 8 and caspase 3 in HL-60 cells. Importantly, shNur77 attenuated 20(S)-Rh2-induced apoptosis and Fas and DR5 expression. Meanwhile, 20(S)-Rh2 promoted Nur77 translocation from the nucleus to mitochondria and enhanced the interaction between Nur77 and Bcl-2, resulting in the exposure of the BH3 domain of Bcl-2 and activation of Bax. Furthermore, 20(S)-Rh2 promoted the differentiation of HL-60 cells as evidenced by Wright-Giemsa staining, NBT reduction assay, and detection of the myeloid differentiation marker CD11b by flow cytometry. Notably, shNur77 reversed 20(S)-Rh2-mediated HL-60 differentiation. Additionally, 20(S)-Rh2 also exhibited an antileukemic effect and induced Nur77 expression in NOD/SCID mice with the injection of HL-60 cells into the tail vein. Together, our studies suggest that the Nur77-mediated signaling pathway is highly involved in 20(S)-Rh2-induced apoptosis and differentiation of AML cells.

Halofuginone dually regulates autophagic flux through nutrient-sensing pathways in colorectal cancer.

Autophagy has a key role in metabolism and impacts on tumorigenesis. Our previous study found that halofuginone (HF) exerts anticancer activity in colorectal cancer (CRC) by downregulating Akt/mTORC1 (mechanistic target of rapamycin complex 1) signaling pathway. But whether and how HF regulates autophagy and metabolism to inhibit cancer growth remains an open question. Here, we unveil that HF activates ULK1 by downregulation of its phosphorylation site at Ser757 through Akt/mTORC1 signaling pathway, resulting in induction of autophagic flux under nutrient-rich condition. On the other hand, HF inactivates ULK1 by downregulation of its phosphorylation sites at Ser317 and Ser777 through LKB1/AMPK signaling pathway, resulting in autophagic inhibition under nutrient-poor condition. Furthermore, Atg7-dependent autophagosome formation is also induced under nutrient-rich condition or blocked in nutrient-poor environment, respectively, upon HF treatment. More interestingly, we also found that HF inhibits glycolysis under nutrient-rich condition, whereas inhibits gluconeogenesis under nutrient-poor condition in an Atg7-dependent manner, suggesting that autophagy has a pivotal role of glucose metabolism upon HF treatment. Subsequent studies showed that HF treatment retarded tumor growth in xenograft mice fed with either standard chow diet or caloric restriction through dual regulation of autophagy in vivo. Together, HF has a dual role in autophagic modulation depending on nutritional conditions for anti-CRC.

Halofuginone and artemisinin synergistically arrest cancer cells at the G1/G0 phase by upregulating p21Cip1 and p27Kip1.

Combinational drug therapy is one of the most promising strategies in modern anticancer research. Traditional Chinese medicine (TCM) formulas represent a wealth of complex combinations proven successful over centuries of clinical application. One such formula used to treat a variety of diseases, including cancer, contains two herbs, whose main active components are Halofuginone (HF) and Artemisinin (ATS). Here we studied the anticancer synergism of HF and ATS in various cancer cell lines and in a xenograft nude mice model. We found that the HF-ATS combination arrested more cells at the G1/G0 phase than either one alone, with the concomitant increased levels of CDK2 inhibitors, p21Cip1 and p27Kip1. By knocking down p21Cip1 and p27Kip1 separately or simultaneously in HCT116 cells and MCF-7 cells, we found that p21Cip1 was required for HF induced G1/G0 arrest, whereas p21Cip1 and p27Kip1 were both required for ATS or HF-ATS combination-mediated cell cycle arrest. Moreover, HF-ATS combination synergistically inhibited tumor growth in xenograft nude mice, and this was associated with the increased levels of p21Cip1 and p27Kip1. Collectively, these data indicate that the upregulation of p21Cip1 and p27Kip1 contributes to the synergistic anticancer effect of the HF-ATS combination.

[Chemical constituents from Mylabris phalerata and their cytotoxic activity in vitro].

Ten compounds were isolated from Mylabris phalerata by using preparative HPLC and column chromatography over MCI gel. On the basis of physical-chemical properties, NMR and MS data analysis, the compounds were identified as 5'-[(1 R,2 R,3 S,6R)-1-hydroxymethyl-2-methyl-3,6-epoxycyclohexane-1,2-dicarboximide]- ethyl-2'-methyl-2'-butenoate (1),cantharidin (2), cyclo-(L-Pro-L-Ala) (3), cyclo-(R-Pro-R-Leu) (4), cyclo-(S-Pro-R-Leu) (5), cyclo-(D-Pro-L-Tyr) (6), indole-3-aldehyde (7), 3-indoleacetic acid (8), valerolactam (9), and 4-hydroxyphthalid (10).Compound 1 was a new compound, and compounds 2-10 were obtained from this genus for the first time. Compounds 1-9 were subjected to cytotoxic activity on HCT-116, HepG2, BGC-823, NCI-H1650, A2780 cell lines, and only compound 2 showed inhibitory effect on all cancer cell lines.

Halofuginone inhibits colorectal cancer growth through suppression of Akt/mTORC1 signaling and glucose metabolism.

The Akt/mTORC1 pathway plays a central role in the activation of Warburg effect in cancer. Here, we present for the first time that halofuginone (HF) treatment inhibits colorectal cancer (CRC) growth both in vitro and in vivo through regulation of Akt/mTORC1 signaling pathway. Halofuginone treatment of human CRC cells inhibited cell proliferation, induced the generation of reactive oxygen species and apoptosis. As expected, reduced level of NADPH was also observed, at least in part due to inactivation of glucose-6-phosphate dehydrogenase in pentose phosphate pathway upon HF treatment. Given these findings, we further investigated metabolic regulation of HF through Akt/mTORC1-mediated aerobic glycolysis and found that HF downregulated Akt/mTORC1 signaling pathway. Moreover, metabolomics delineated the slower rates in both glycolytic flux and glucose-derived tricarboxylic acid cycle flux. Meanwhile, both glucose transporter GLUT1 and hexokinase-2 in glycolysis were suppressed in CRC cells upon HF treatment, to support our notion that HF regulates Akt/mTORC1 signaling pathway to dampen glucose uptake and glycolysis in CRC cells. Furthermore, HF retarded tumor growth in nude mice inoculated with HCT116 cells, showing the anticancer activity of HF through metabolic regulation of Akt/mTORC1 in CRC.

Prenylated benzoylphloroglucinols and xanthones from the leaves of Garcinia oblongifolia with antienteroviral activity.

An acetone extract of the leaves of Garcinia oblongifolia showed antiviral activity against enterovirus 71 (EV71) using a cytopathic effect inhibition assay. Bioassay-guided fractionation yielded 12 new prenylated benzoylphloroglucinols, oblongifolins J-U (1-12), and five known compounds. The structures of 1-12 were elucidated by spectroscopic analysis including 1D- and 2D-NMR and mass spectrometry methods. The absolute configurations were determined by a combination of a Mosher ester procedure carried out in NMR tubes and ECD calculations. Compared to ribavirin (IC50 253.1 µM), compounds 1, 4, and 13 exhibited significant anti-EV71 activity in vitro, with IC50 values of 31.1, 16.1, and 12.2 µM, respectively. In addition, the selectivity indices of these compounds were 1.5, 2.4, and 3.0 in African green monkey kidney (Vero) cells, respectively.

Anti-oxidative and TNF-α suppressive activities of puerarin derivative (4AC) in RAW264.7 cells and collagen-induced arthritic rats.

Puerarin is a major active ingredient extracted from the root of P. lobata, a traditional Chinese herb, and possesses anti-oxidative and anti-inflammatory activities. However, the low oral bioavailability of puerarin limits its further application. Therefore, we synthesized tetraacetyl puerarin (4AC) through acetylation to improve its liposolubility and bioavailability. In the present investigations, we tested the anti-oxidative and TNF-α suppressive activity of 4AC in lipopolysaccharide (LPS)-induced RAW264.7 macrophages and bovine type II collagen-induced arthritic (CIA) rats. The results showed that 4AC retained the bioactivity of puerarin. And 4AC significantly increased the activity of SOD and reduced the level of MDA both in vitro and in vivo. It also improved the level of GSH-PX and the total antioxidant capacity in vivo. Furthermore, it dramatically decreased TNF-α level in the cultured supernatant of RAW264.7 cells treated with LPS and in the serum of CIA rats. These initial results indicated that 4AC had a potential therapeutic effect on CIA rats through an anti-oxidative and TNF-α suppressive activity. In addition, the molecular mechanism of anti-oxidation of 4AC was explored by testing the MAPKs/NF-κB signaling pathway. The results showed that 4AC significantly inhibited NF-κB expression and down-regulated the levels of p-ERK and p-JNK in LPS-activated RAW264.7 cells. These results indicated that 4AC had bioactive anti-oxidative effects and suggest the potential value of 4AC for the treatment of rheumatoid arthritis.

A new triterpene saponin from Androsace integra.

A new triterpene saponin, androsacin (1), along with two known compounds, ardisiacrispin A (2) and saxifragifolin A (3), were isolated from the whole plants of Androsace integra. The chemical structure of the new compound was elucidated as 3ß-O-{ß-D-glucopyranosyl-(1→4)-O-ß-D-xylopyranosyl-(1→2)-O-ß-D-glucopyranosyl-(1→4)-[O-ß-D-glucopyranosyl-(1→2)]-α-L-arabinopyranosyl}-16α-hydroxy-13ß,28-epoxy-olean-30-al on the basis of spectral evidence. Ardisiacrispin A (2) was cytotoxic toward HepG2 cancer cell with the GI(50) value of 1.56µM.

[Proportion of Coptidis rhizoma and Evodiae fructus in the compound preparation: its effect in inducing apoptosis of SGC-7901 cells].

OBJECTIVE: To investigate the effect of water extracts of Coptidis Rhizoma and Evodiae Fructus (CREF) on the proliferation and apoptosis of human gastric carcinoma cells (SGC-7901) and determine the optimal proportion of Coptidis rhizoma to Evodiae fructus. METHODS: The growth inhibition of SGC-7901 cells treated with the water extracts of CREF of varying proportions was tested with MTT assay. The cell apoptotic rate and mitochondrial membrane potential were analyzed with flow cytometry. RESULTS: The water extract of CREF with Coptidis Rhizoma: Evodiae Fructus proportions at 1:6, 2:5, 3:4, 4:3, 5:2, and 6:1 all significantly inhibited the growth of SGC-7901 cells after a 24-h or 48-h treatment (P<0.05). The growth inhibition and cell death ratio both exhibited a dose-dependent pattern of Coptidis Rhizoma. Flow cytometry analysis showed that, after treatment of the cells with CREF at the proportions of 1:6, 2:5, 3:4, 4:3, 5:2, and 6:1, the apoptotic rate were (8.50 ∓ 1.59)%, (9.90 ∓ 1.01)%, (17.15∓1.68)%, (21.55 ∓ 1.97)%, (34.10 ∓ 1.06)% and (34.40 ∓ 1.02)%, respectively, all significantly higher than that in the control group [(1.69 ∓ 1.91)%, P<0.05]. JC-1 Kit staining showed that mitochondrial membrane potential of SGC-7901 cells was decreased and the ratio of green to red fluorescence increased significantly after incubation with CREF. CONCLUSION: CREF can inhibit the growth and induce apoptosis of SGC-7901 cells, and the strongest effect is achieved at the optimal proportion of Coptidis Rhizoma and Evodiae Fructus at 6:1.

Simultaneous determination of nine nucleosides and nucleobases in different Fritillaria species by HPLC-diode array detector.

A sensitive and reliable HPLC-diode-array detector method was developed for the first time to simultaneously determine nine nucleosides and nucleobases including uracil, cytidine, guanine, uridine, thymine, inosine, guanosine, thymidine and adenosine in 13 different Fritillaria species. The analysis was performed on a BaseLine C18 column with a gradient of acetonitrile in water at a flow rate of 0.8 mL/min. The diode-array detector wavelength was set at 260 nm for the UV detection of nucleosides and nucleobases. Satisfactory separation of these compounds was obtained in less than 40 min. The optimized method provided good linear relation (r(2)>0.9995 for all the investigated analytes), satisfactory precision (RSD <1.51%) and good recovery (from 97.64 to 101.16%). The established method was successfully applied to simultaneous determination of nine nucleosides and nucleobases in 61 batches of samples from 13 Fritillaria species collected from different habitats in China, which could be helpful to control the quality of Fritillaria bulbs.

Two new xanthones isolated from the stem bark of Garcinia lancilimba.

Two new xanthones, 1,5,6-trihydroxy-6',6'-dimethyl-2H-pyrano(2',3':3,4)-2-(3-methylbut-2-enyl)xanthone (1) and 1,6,7-trihydroxy-6',6'-dimethyl-2H-pyrano(2',3':3,2)-4-(3-methylbut-2-enyl)xanthone (2), have been isolated from the stem bark of Garcinia lancilimba (Guttiferae), together with six known xanthones. Their structures were identified on the basis of extensive spectral evidence including detailed 2D NMR and HR-MS data. Two new compounds showed moderate inhibitory effect on human breast cancer MDA-MB-435S cell line.

Cytotoxic prenylated phenolic compounds from the twig bark of Garcinia xanthochymus.

Three new hydroxylated xanthones with prenyl or geranyl substituents, compounds 1-3, were isolated from the twig bark of Garcinia xanthochymus, along with the four known compounds 1,4,5,6-tetrahydroxy-7,8-diprenylxanthone (4), 1,3,5,6-tetrahydroxy-4,7,8-triprenylxanthone (5), garciniaxanthone E (6), and 6-prenylapigenin (7). Their structures were elucidated by extensive spectroscopic analysis, including 1D- and 2D-NMR as well as HR-MS experiments. All compounds showed moderate cytotoxicities against breast cancer (MDA-MB-435S) and lung adenocarcinoma (A549) cell lines, but lacked antifungal activity against Candida albicans.

[Effect of combination glycyrrhiizin and triptolide on TNF-alpha and IL-10 in serum of collagen induced arthritis rats].

OBJECTIVE: To observe the effects of combination therapy with glycyrrhizin (GL) and triptolide (TP) on collagen-induced arthritis (CIA) rats. METHOD: Sixty male SD rats were randomly divided into 6 groups: the model group, the TP group, the GL group, and combination 1, 2, 3 groups. The models were induced by collagen type II. The arthritis index (AI) and the edema rate were detected as curative effect, and the level of antibodies to collagen, TNF-alpha and IL-10 were measured by ELISA. RESULT: The combination therapy with GL and TP significantly reduced the paw edema and arthritis index of CIA rats (P <0. 01 ), and the combination therapy can increase the level of IL-10, while decrease the level of TNF-alpha, and the level of antibodies to collagen decreased too (P <0.05, P <0.01). CONCLUSION: Combine 26.78 mg x kg(-1) GL with 13.40 microg x kg(-1) TP can significantly inhibited the CIA, and the effect equal to the dosage of 17. 86 microg x kg(-1) TP. It supports the possible of GL in combination with TP to reduce the dose and side effects related to TP.

Therapeutic effect of combined triptolide and glycyrrhizin treatment on rats with collagen induced arthritis.

For investigating the effects of a combination therapy of triptolide (TP) with glycyrrhizin (GL) in rats with collagen-induced arthritis (CIA), the arthritic index was examined, and the levels of anti-CII IgG, TNF-alpha and IL-10 in serum were measured by ELISA. Our results showed that combined triptolide and glycyrrhizin treatment (TP 13.40 microg, GL 26.78 mg) can reduce the arthritic index of CIA rats and decrease the level of anti-CII IgG and TNF-alpha in serum. The observed effect was similar to the one measured upon application of TP 17.86 microg, GL 26.78 mg and TP 17.86 microg. The level of IL-10 was not significantly different among the rats of the TP 17.86 microg, of the TP 17.86 microg, GL 26.78 mg and of the TP 13.40 microg, GL 26.78 mg groups while the IL-10 levels in rats of the TP 13.40 microg and GL 26.78 mg groups were significantly higher. Combined triptolide 13.40 microg and glycyrrhizin 26.78 mg can therefore significantly inhibit collagen induced arthritis, and the effect was similar to the one of triptolide at 17.86 microg.

Gambogic acid and epigambogic acid, C-2 epimers with novel anticancer effects from Garcinia hanburyi.

Gambogic acid, usually isolated as an inseparable stereomeric mixture of C-2 epimers, was newly separated into two epimers (1 and 2) from the gamboges of Garcinia hanburyi. The stereochemistry at C-2 was clearly defined by extensive spectroscopic analysis and direct comparison of NMR and HPLC data with those of the known R-epimer. Both epimers were examined for their cytotoxicities against human leukemia K562 (K562/S) and doxorubicin-resistant K562 (K562/R) cell lines. Different from doxorubicin (IC (50) = 10.78 microM for K562/R and 0.66 microM for K562/S), epimers 1 and 2 exhibited similar activities against both cell lines (IC(50) = 1.32 and 0.89 microM for 1, IC(50) = 1.11 and 0.86 microM for 2). These results suggested that both epimers were not multidrug resistance (MDR) substrates. Furthermore, epimers 1 and 2 were tested for their inhibitory effects against six human cytochrome P-450 enzymes. Epimers 1 and 2 showed little inhibitory effects toward five of the enzymes except CYP2C9. Interestingly, when tested against CYP2C9, S-epimer 2 had an inhibitory effect 20-fold stronger than that of R-epimer 1.