Protective effect of SERCA2a-SUMOylation by SUMO-1 on diabetes-induced atherosclerosis and aortic vascular injury.

Diabetes is a major risk factor for cardiovascular disease. However, the exact mechanism by which diabetes contributes to vascular damage is not fully understood. The aim of this study was to investigate the role of SUMO-1 mediated SERCA2a SUMOylation in the development of atherosclerotic vascular injury associated with diabetes mellitus. ApoE-/- mice were treated with streptozotocin (STZ) injection combined with high-fat feeding to simulate diabetic atherosclerosis and vascular injury. Human aortic vascular smooth muscle cells (HAVSMCs) were treated with high glucose (HG, 33.3 mM) and palmitic acid (PA, 200 µM) for 24 h to mimic a model of diabetes-induced vascular injury in vitro. Aortic vascular function, phenotypic conversion, migration, proliferation, intracellular Ca2+ concentration, the levels of small ubiquitin-like modifier type 1 (SUMO1), SERCA2a and SUMOylated SERCA2a were detected. Diabetes-induced atherosclerotic mice presented obvious atherosclerotic plaques and vascular injury, companied by significantly lower levels of SUMO1 and SERCA2a in aorta. HG and PA treatment in HAVSMCs reduced the expressions of SUMO1, SERCA2a and SUMOylated SERCA2a, facilitated the HAVSMCs phenotypic transformation, proliferation and migration, attenuated the Ca2+ transport, and increased the resting intracellular Ca2+ concentration. We also confirmed that SUMO1 directly bound to SERCA2a in HAVSMCs. Overexpression of SUMO1 restored the function and phenotypic contractile ability of HAVSMCs by upregulating SERCA2a SUMOylation, thereby alleviating HG and PA-induced vascular injury. These observations suggest an essential role of SUMO1 to protect diabetes-induced atherosclerosis and aortic vascular injury by the regulation of SERCA2a-SUMOylation and calcium homeostasis.

Rapid identification of chemical compositions from three species of Siegesbeckiae Herba by ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry in combination with deoxyribonucleic acid barcoding.

Siegesbeckiae Herba, a traditional Chinese medicine, originates from Siegesbeckia orientalis, S. glabrescens, and S. pubescens in the Pharmacopoeia of the People's Republic of China. However, accurate identification of decoction pieces from the three plants remains a challenge. In this study, 26 batches of Siegesbeckiae Herba were identified by deoxyribonucleic acid barcoding, and their chemical compositions were determined using ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry. The results showed that the internal transcribed spacer 2 and internal transcribed spacer 1-5.8 S- internal transcribed spacer 2 sequences could distinguish three species. In total, 48 compounds were identified including 12 marker compounds screened for three species using the partial least square discriminant analysis. Among these, two diterpenoids 16-O-malonylkirenol and 15-O-malonylkirenol, and a novel diterpenoid 15,16-di-O-malonylkirenol were isolated and identified. A convenient method for the identification of Siegesbeckiae Herba was established using kirenol and 16-O-acetlydarutoside as control standards by thin-layer chromatography. Unexpectedly, none of the batches of S. orientalis contained kirenol, which did not meet the quality standards of Siegesbeckiae Herba, suggesting that the rationality of kirenol as a quality marker for S. orientalis should be further investigated. The results of this study will contribute to the quality control of Siegesbeckiae Herba.

Unexpected Cascade Sequence Forming the C(sp3)-N/C(sp2)-C(sp2) Bond: Direct Access to γ-Lactam-Fused Pyridones with Anticancer Activity.

An unexpected Ugi cascade reaction was developed for the facile construction of γ-lactam-fused pyridone derivatives with high tolerance of substrates. A C(sp3)-N bond and a C(sp2)-C(sp2) bond were formed together, accompanied by a chromone ring-opening in Ugi adducts, under the basic conditions without any metal catalyst for the whole process. Screening data of several difficult-to-inhibit cancer cell lines demonstrated that 7l displayed a high cytotoxicity against HCT116 cells (IC50 = 5.59 ± 0.78 µM). Taken together, our findings revealed new insights into the molecular mechanisms underlying compound 7l and provided potential usage of this scaffold for cancer therapeutics.

Toosendanin inhibits colorectal cancer cell growth through the Hedgehog pathway by targeting Shh.

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. This complex and often fatal disease has a high mortality rate. The Hedgehog (Hh) signaling pathway is crucial in CRC. Many studies have indicated that Shh is overexpressed in cancer stem cells (CSCs), and shh overexpression is positively correlated with CRC tumorigenesis. New drugs that kill CRC cells through the Hh pathway are needed. Toosendanin (TSN), a natural triterpenoid saponin extracted from the bark or fruit of Melia toosendan Sieb. et Zucc, can inhibit various tumors. Here, we investigated the effects of TSN in CRC and explored the possible targets and mechanisms. Shh-Light Ⅱ cells were treated with TSN and tested by dual luciferase reporter assays to determine the relationship with the Hh pathway. Cell Counting Kit-8 (CCK-8) assays were used to test the inhibitory effects of TSN on CRC cells. The expression of Hh components after TSN treatment was detected using western blots and quantitative reverse transcription polymerase chain reaction. Cellular thermal shift assays confirmed the targets of TSN. The same effects of TSN on xenograft tumor growth were investigated in vivo. The average weight, volume of the finally resected tumor, and the expression of Shh in the TSN-treated groups were significantly lower than those of the control group. This result strongly suggested that TSN administration inhibited CRC growth in vivo. Our research preliminarily demonstrated that the target of TSN was Shh and that TSN inhibits CRC cell growth by inhibiting the Hh pathway, identifying a new anticancer molecular mechanism of TSN in CRC.

[Diterpenoids as PPARγ agonists from Siegesbeckia pubescens and their anti-inflammatory effects in vitro].

This study aims to investigate the PPARγ agonists isolated from the aqueous extract of Siegesbeckia pubescens( SPA) and their anti-inflammatory activities in vitro. The 293 T cells transfected transiently with PPARγ recombinant plasmid were used as a screening model to guide the isolation of PPARγ activitating components,and then PPARγ activities were measured by double luciferase reporter gene assay. The chemical structures were identified by chromatography or spectroscopic techniques. Furthermore,a UC inflammatory model in vitro was established on HT-29 cells by stimulating with TNF-α． The mRNA levels and secretion of proinflammatory cytokines on HT-29 cells,such as IL-1ß,TNF-α,IL-8,were detected by RT-PCR and ELISA. The results showed that five diterpenoids were obtained from the fraction D_(50) with the strongest PPARγ activity among others in SPA,and determined as kirenol( 1),darutigenol( 2),enantiomeric-2-ketone-15,16,19-three hydroxypinomane-8( 14)-ene-19-O-ß-D-glucoside( 3),darutoside( 4),enantiomeric-2-ß,15,16,19-four hydroxypinomane-8( 14)-ene-19-O-ß-D-glucoside( 5),respectively. All the compounds exhibited active effects on PPARγ in a concentration-dependent manner( P<0. 01). In addition,compound 1 significantly inhibited the expression of IL-1ß mRNA and secretion of IL-8 on HT-29 cells inflammation model( P<0. 001); both compounds 2 and 3 effectively inhibited the expression of IL-1ß,TNF-α,IL-8 mRNA and secretion of IL-8( P<0. 01 or P<0. 001),although at different extent; compound 4 significantly inhibited the expression of IL-1ß and TNF-α mRNA( P<0. 01 or P<0. 001),while compound 5 inhibited the expression of IL-1ß mRNA obviously( P<0. 001). In conclusion,the diterpenoids 1-5 isolated from S. pubescens have the PPARγ activation activities and potential effects of anti-UC in vitro.

Cynanbungeigenin C and D, a pair of novel epimers from Cynanchum bungei, suppress hedgehog pathway-dependent medulloblastoma by blocking signaling at the level of Gli.

Uncontrolled excessive activation of Hedgehog (Hh) signaling pathway is linked to a number of human malignant tumorigenesis. To obtain valuable Hh pathway inhibitors from natural product, in present study, a pair of novel epimers, Cynanbungeigenin C (CBC) and D (CBD) from the plant Cynanchum bungei Decne were chemically characterized by multiple spectroscopic data and chemical derivatization, and evaluated for their inhibition on Hh pathway. Mechanistically, CBC and CBD block Hh pathway signaling not through targeting Smo and Sufu, but at the level of Gli. In addition, both eipmers significantly suppress Hh pathway-dependent Ptch+/-; p53-/- medulloblastoma in vitro and in vivo. Furthermore, both CBC and CBD inhibited two Smo mutants induced Hh pathway activation, which suggested that they are potential compounds for the treatment of medulloblastoma with primary or acquired resistance to current Smo inhibitors. These results highlight the potential of CBC and CBD as effective lead compounds in the treatment of medulloblastoma and other Hh-dependent malignancy.

Three new alkaloids from Veratrum grandiflorum Loes with inhibition activities on Hedgehog pathway.

Three new steroidal alkaloids 1-3, together with four known compounds 4-7, were isolated from the ethanol extract of Veratrum grandiflorum Loes. Their structures were elucidated by NMR (1D and 2D NMR) and MS spectroscopic data. The inhibition activities on Hedgehog (Hh) pathway were evaluated using a cell-based bioassay system (Shh-LIGHT 2 cells). The results showed that compounds 1-3 and 5 displayed inhibitory activities obviously with the IC50 values of 0.63-3.11µM. Among them, compound 5 showed the most prominent inhibition activity (IC50=0.63±0.02µM). Thus, these active alkaloids may be potent natural compounds as Hh pathway inhibitors for the treatment of various cancers.

Two New Steroidal Aglycones from Roots of Cynanchun paniculatum.

Two new 13, 14/14, 15-disecopregnane-type skeleton C21 steroidal aglycones, neocynapanogenin G (1) and neocynapanogenin H (2), were isolated from the hydrolyzed extract of the CHCl3 soluble extract of the roots of Cynanchun paniculatum. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D and 2D NMR spectroscopy. Compound 1 displayed signifidant inhibition of the Hedgehog signaling pathway in vitro.

Stephanthraniline A suppressed CD4(+) T cell-mediated immunological hepatitis through impairing PKCθ function.

Stephanthraniline A (STA), a C21 steroid isolated from Stephanotis mucronata (Blanco) Merr., was previously shown to inhibit T cells activation and proliferation in vitro and in vivo. The purpose of this study was to further evaluate the in vivo immunosuppressive activity of STA and to elucidate its potential mechanisms. The results showed that pretreatment with STA significantly attenuated concanavalin A (Con A)-induced hepatitis and reduced CD4(+) T cells activation and aggregation in hepatic tissue in mice. STA directly suppressed the activation and proliferation of Con A-induced CD4(+) T cells, and inhibited NFAT, NFκB and MAPK signaling cascades in activated CD4(+) T cells in vitro. Moreover, it was proved that STA inhibited T cells activation and proliferation through proximal T cell-receptor (TCR) signaling- and Ca(2+) signaling-independent way. The molecular docking studies predicted that STA could tight bind to PKCθ via five hydrogen. The further findings indicated STA directly inhibited PKCθ kinase activity, and its phosphorylation in activated CD4(+) T cells in vitro. Collectively, the present study indicated that STA could protect against CD4(+) T cell-mediated immunological hepatitis in mice through PKCθ and its downstream NFAT, NFκB and MAPK signaling cascades. These results highlight the potential of STA as an effective leading compound for use in the treatment of CD4(+) T cell-mediated inflammatory and autoimmune diseases.

Two New 8, 14-seco-pregnane Steroidal Aglycones froni Roots of Cynanchum bungei.

Two new 8, 14-seco skeleton C(21) steroidal aglycones, cynanbungeigenin A (1) and cynanbungeigenin B (2), were isolated from the hydrolyzed extract of the EtOAc soluble extract of the roots of Cynanchum bungei. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D and 2D NMR spectroscopy.

Proanthocyanidins from the bark of Metasequoia glyptostroboides ameliorate allergic contact dermatitis through directly inhibiting T cells activation and Th1/Th17 responses.

OBJECTIVE: The leaves and bark of Metasequoia glyptostroboides are used as anti-microbic, analgesic and anti-inflammatory drug for dermatic diseases in Chinese folk medicine. However, the pharmacological effects and material basis responsible for the therapeutic use of this herb have not yet been well studied. The objectives of this study were to evaluate the anti-inflammatory effects of the proanthocyanidin fraction from the bark of M. glyptostroboides (MGEB) and to elucidate its immunological mechanisms. MATERIALS AND METHODS: The anti-inflammatory activity of MGEB was evaluated using 2,4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis (ACD) in mice. Its potential mechanisms were further investigated by determining its effects on Con A-induced T cell activation and Th1/Th17 responses in vitro. RESULTS: Both intraperitoneal injection and oral administration of MGEB significantly reduced the ear swelling in DNFB-induced ACD mice. MGEB inhibited Con A-induced proliferation and the expression levels of cell surface molecules CD69 and CD25 of T cells in vitro. MGEB also significantly decreased the production of Th1/Th17 specific cytokines (IL-2, IFN-γ and IL-17) and down-regulated their mRNA expression levels in activated T-cells. CONCLUSIONS: MGEB could ameliorate ACD, at least in part, through directly inhibiting T cells activation and Th1/Th17 responses.

Antioxidant Capacity and Proanthocyanidin Composition of the Bark of Metasequoia glyptostroboides.

Metasequoia glyptostroboides Hu et Cheng is the only living species in the genus Metasequoia Miki ex Hu et Cheng (Taxodiaceae), which is well known as a "living fossil" species. In the Chinese folk medicine, the leaves and bark of M. glyptostroboides are used as antimicrobic, analgesic, and anti-inflammatory drug for dermatic diseases. This study is the first to report the free radical scavenging capacity, antioxidant activity, and proanthocyanidin composition of the bark of M. glyptostroboides. We observed total of six extracts and fractions, which were easily obtained by water-ethanol extraction and followed by a further separation with D101 resin column chromatography, had significant DPPH radical, superoxide anion radical, and hydroxyl radical scavenging capacity, total antioxidative capacity (T-AOC), lipid peroxidation inhibitory activity, and metal ions chelating capacity. The fraction MGEB, which was obtained by 60% ethanol extraction and followed by a further separation with D101 resin column chromatograph, possessed the highest proanthocyanidin content and the highest free radical scavenging and antioxidant activities. Furthermore, MGEB could significantly protect against CCl4 induced acute liver injury through inhibition of oxidative stress in mice. In addition, ten proanthocyanidins were isolated from MGEB, and six of them were firstly reported from this plant.

Steroidal aglycones from stems of Marsdenia tenacissima that inhibited the hedgehog signaling pathway.

Two novel steroidal aglycones, together with four known ones, were isolated from the hydrolysis extract of the CHCl3 soluble extract of the stems of Marsdenia tenacissima. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D and 2D NMR spectroscopy. These compounds displayed inhibition of the Hedgehog signaling pathway in vitro.

Three novel immunosuppressive steroidal glycosides from the stems of Stephanotis mucronata.

Three novel and one known C21 steroidal glycosides were isolated from the stems of Stephanotis mucronata. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods. The four C21 steroidal glycosides displayed significant immunosuppressive activities in vitro.

Stephanthraniline A inhibits the proliferation and activation of T cells in vitro and in vivo.

Stephanthraniline A (STA) isolated from the stems of Stephanotis mucronata (Blanco) Merr. was evaluated for their suppression on T cells' immune responses in vitro and in vivo. In vivo, oral administration of STA significantly inhibited T cell-mediated delayed-type hypersensitivity (DTH) response. In vitro, STA has inhibitory effects on T cell proliferation induced by CD3/CD28 cross-linking or Con A; additionally, CD4(+) T cells are more sensitive to this inhibition than CD8(+) T cells. STA also suppressed the production of cytokines (IL-2, IFN-γ, IL-4 and IL-17) and mRNA expression of the genes associated with T cell activation, proliferation and differentiation. Our data indicate that STA inhibits the proliferation of T cells by inducing cell cycle arrest but not inducing apoptosis. The inhibitory mechanism of STA on T cells was correlated with the gene change related to multi-signal transduction pathways. Furthermore, we also provided lines of evidence that STA, distinct from glucocorticoids, did not activate the glucocorticoid receptor. These findings would be beneficial for further understanding the therapeutic effects of S. mucronata in the treatment of autoimmune diseases. It also suggested the potential of the natural steroid STA as the effective candidate compounds for use in the treatment of inflammatory and autoimmune diseases.

Chemical composition and antioxidant activities of different polysaccharides from the roots of Angelica dahurica.

The total crude polysaccharides (CADPs), isolated from the roots of Angelica dahurica by H(2) O extraction, EtOH precipitation, and dialysis, and the four fractions ADP1, ADP2, ADP3, and ADP4, obtained by gel filtration of the CADPs, were analyzed to characterize their composition and evaluated for their antioxidant activity using different in vitro tests such as the malondialdehyde (MDA)-production, the ferrous ion (Fe(2+) )-chelating, and the HO(.) radical-scavenging assays. The predominant neutral monosaccharides in the four fractions were identified as arabinose, galactose, and glucose, while the composition and ratio of the monosaccharides were different between the fractions. The CADPs and its fractions were found to significantly inhibit lipid peroxidation, chelate Fe(2+) , and scavenge HO(.) radicals, indicating that these polysaccharides possessed antioxidant activity. Among the four fractions, ADP4 exhibited the strongest antioxidant activity, which was stronger than that of the control antioxidant vitamin E (Vit E). Taken together, the chemical composition of these polysaccharides might affect their antioxidant activity, and ADP4 could be explored as a source of potential novel natural antioxidants for food and pharmaceutical purposes.

Comparison of immunosuppressive activity of stephanoside E and its aglycone from Stephanotis mucronata in vitro.

Stephanoside E (STE) and its aglycone Stephanthraniline A (STA) isolated from the stems of Stephanotis mucronata (Blanco) Merr. were evaluated for their suppressive potentials on Th1 and Th2 immune responses in vitro, and the effects of the C-3 sugar chains on their activities were discussed. STE and STA significantly inhibited Con A and LPS-induced splenocyte proliferation, and reduced the production of Th1/Th2 cytokines (IL-2, IFN-γ, IL-4, and IL-10) from Con A-stimulated splenocytes in a concentration-dependent manner. The mRNA expression levels of Th1/Th2 cytokines (IL-2, IFN-γ, IL-4, and IL-10) and transcription factors (T-bet and GATA-3) in Con A-stimulated splenocytes were also suppressed by STE and STA. The suppressive effect of STA on Th1 and Th2 immune responses in vitro was stronger than that of STE. These findings suggested that both STE and STA could simultaneously inhibit Th1/Th2 immune responses, and the glycosyl formation at the position C-3 of STA could decrease the immunosuppressive activity in vitro.

Antitumor and immunomodulatory activity of polysaccharides from the roots of Actinidia eriantha.

AIM OF THE STUDY: The roots of Actinidia eriantha Benth (Actinidiaceae) have been used for cancers in the Chinese folk medicine. The present study aimed at evaluating the antitumor potentials of the polysaccharides from the roots of Actinidia eriantha and elucidating their immunological mechanisms by determining the effects on the growth of tumor transplanted in mice and the immune response in tumor-bearing mice. MATERIALS AND METHODS: The total polysaccharide AEP and fours purified polysaccharides AEPA, AEPB, AEPC and AEPD were isolated and purified from the roots of Actinidia eriantha by hot water extraction, ethanol precipitation, dialysis and gel filtration. Their effects on the growth of mouse transplantable tumor, splenocyte proliferation, the activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL), production of cytokines from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice were measured. RESULTS: AEP and four purified polysaccharides could not only significantly inhibit the growth of mouse transplantable tumor, but also remarkably promote splenocytes proliferation, NK cell and CTL activity, IL-2 and IFN-gamma production from splenocytes, and serum antigen-specific antibody levels in tumor-bearing mice. CONCLUSIONS: The antitumor activity of AEP and four purified polysaccharides might be achieved by improving immune response, and the composition of the monosaccharides, uronic acid contents and molecular weight could affect their antitumor and immunomodulatory activity.

Stemucronatoside K, a novel C(21) steroidal glycoside from Stephanotis mucronata, inhibited the cellular and humoral immune response in mice.

Stephanotis mucronata (Blanco) Merr. has been used for rheumatoid arthritis in Chinese folk herb medicine. Guided by bioactive test, a novel potent immunosuppressive C(21) steroidal glycoside stemucronatoside K (SMK) was isolated from this plant. Its structure was elucidated on the basis of the chemical evidence and extensive spectroscopic methods. We investigated the immunosuppressive effects of SMK in vitro and in vivo. SMK significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR mice were immunized subcutaneously with OVA on the first day and administered intraperitoneally with SMK at the doses of 2.5, 5, and 10 mg/kg once daily for 10 days. At 24 h after the last administration, mitogen- and OVA-stimulated splenocyte proliferation, the levels of cytokines from splenocytes, and specific antibody titers in serum were measured. SMK significantly inhibited Con A-, LPS- and OVA-induced splenocyte proliferation in the immunized mice in a dose-dependent manner. OVA-specific IgG, IgG1, and IgG2b antibody titers were significantly reduced by SMK compared with the control group. SMK also significantly decreased OVA-induced interleukin-2 (IL-2), interferon-gamma (IFN-gamma), and IL-4 production from splenocytes in the OVA-immunized mice. These results demonstrated that SMK could suppress the cellular and humoral immune response in mice. This study provided evidence to understand the therapeutic effects of S. mucronata and an immunosuppressive natural product compound to further researches to be developed as immunosuppressant.

[Saponins from roots of Stephanotis mucronata].

OBJECTIVE: To study the chemical constituents from n-BuOH fraction of the roots of Stephanotis mucronata. METHOD: The compounds were separated by chromatographic methods. A combination of UV, MS, and NMR spectroscopic methods was applied to identify structure of these compounds. RESULT: Four oleane saponins were isolated and identified as sitakisoside VII (1), sitakisoside VI (2), sitakisoside II (3), and sitakisoside I (4). CONCLUSION: These four compounds were obtained for the first time from this plant.