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1.
J Ethnopharmacol ; 288: 114938, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34999144

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Silybum marianum is a traditional Chinese medicine that has been used for treating liver disease. Silybin consisting of silybin A and silybin B, is a member of Silybum marianum, and exerts a therapeutic effect on many diseases. However, the protective effect of silybin on cisplatin-induced neurotoxicity and the stereoisomer contributing to the effect remain unknown. AIM OF THE STUDY: The present study aimed to study the effect of silybin on cisplatin-induced neuronal injury, compare the difference of protective effect between silybin A and silybin B, and the potential mechanism. MATERIALS AND METHODS: High performance liquid chromatography (HPLC) was used to separate silybin A and silybin B. X-ray crystallographic analysis in combination with experimental and calculated ECD were performed to identify the structure of silybin A and silybin B. The toxicity of the silybin or cisplatin against murine hippocampal neuronal HT22 cells was determined through MTT assay. The cell cycle and cell apoptosis were measured by PI staining and Annexin V-FITC/PI staining, respectively, and then subjected to flow cytometry. Western blot analysis was conducted to quantify the expression of proteins related to apoptosis and DNA damage. Immunofluorescence was used to evaluate the expression of DNA damage marker. In vivo experiment, the behavioral analysis was determined through pole test, swimming test and Morris water maze test. The index of superoxide dismutase (SOD), reduced glutathione (GSH), total antioxidant capacity (T-AOC) and lipid peroxidation (LPO) were examined to evaluate the antioxidant capacity in mice brain. Nissl staining and Tunel assay were used to detect the neuronal viability and apoptosis in hippocampus. RESULTS: We successfully separated and identified silybin A and silybin B. We found both silybin A and silybin B alleviated cisplatin-induced apoptosis and cell cycle arrest in HT22 cells, and silybin B was more effective. We chose silybin B for further mechanism investigation, and found silybin B alleviated DNA damage by enhancing phosphorylation of ATR and decreasing expression of γ-H2AX. In the in vivo experiment, we observed that silybin B markedly improved the behavioral abnormalities in cisplatin-treated mice, reduced LPO level while increased SOD, GSH and T-AOC in mice brain tissue. Nissl staining and Tunel assay showed that silybin B alleviated cisplatin-induced hippocampal damage. CONCLUSIONS: These results suggest that silybin B might serve as a promising drug candidate in mitigating cisplatin-induced neural injury in the brain and thereby improving the chemotherapeutic outcomes.

2.
Oxid Med Cell Longev ; 2021: 5526053, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34471466

RESUMO

Copper/zinc superoxide dismutase (SOD1) can clear cisplatin- (CP-) induced excessive reactive oxygen species (ROS), but exogenous SOD1 cannot enter cells because of its low biomembrane permeability. Cell-penetrating peptides (CPPs) can rapidly cross plasma membranes. This study is aimed at identifying an efficient and stable CPP-SOD1 and investigating its effects on CP-induced nephrotoxicity. We recombined SOD1 with 14 different CPPs and purified them using an NTA-Ni2+ column. In in vitro experiments, CPPs-SOD1 cell membrane penetration ability and JNK/p38 MAPK signaling pathway were evaluated using Western blotting. ROS production, mitochondrial membrane potential (MMP), and cell apoptosis were determined using flow cytometry and immunofluorescence staining in VERO and HK-2 cells. For in vivo experiments, mice were administered PSF-SOD1 for 2 h before cotreatment with a single CP injection for an additional 4 days. Blood and kidney samples were collected for renal function assessment (creatinine, urea nitrogen, histopathology, TUNEL assay, and JNK/p38 MAPK signaling pathway). Compared with TAT-SOD1, we found that PSF-SOD1 is more efficient at crossing the cell membrane and is stable after transduction into cells. Pretreatment with PSF-SOD1 inhibited CP-induced apoptosis, ROS generation, and JNK/p38 MAPK activation and restored CP-induced MMP loss in VERO and HK-2 kidney cells. Treatment of mice with PSF-SOD1 inhibited CP-induced serum creatinine, blood urea nitrogen elevation, and JNK/p38 MAPK activation. H&E staining and TUNEL assay indicated that kidney tissue damage was alleviated following PSF-SOD1 pretreatment. Overall, PSF-SOD1 ameliorated CP-induced renal damage by partially reducing oxidative stress and cell apoptosis by regulating JNK/p38 MAPK signaling pathway and might be a better cytoprotective agent than TAT-SOD1.

3.
Angew Chem Int Ed Engl ; 60(36): 19609-19613, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34196083

RESUMO

A combined strategy of building blocks recognition and molecular network construction, termed the building blocks-based molecular network (BBMN), was first presented to facilitate the efficient discovery of novel natural products. By mapping the BBMN of the total alkaloid fraction of Flueggea suffruticosa, three Securinega alkaloids (SEAs) with unusual chemical architectures, suffranidines A-C (1-3), were discovered and isolated. Compound 1 characterizes an unprecedented 8/5/6/5/6/6/6/6-fused octacyclic scaffold with a unique cage-shaped 3-azatricyclo[6.4.0.03,11 ]dodecane core. Compounds 2 and 3 are highly modified SEA dimers that incorporate additional C6 motifs. A hypothetical biosynthetic pathway for 1-3 was proposed. In addition, 1 significantly induced neuronal differentiation and neurite extension by upregulating eukaryotic elongation factor 2 (eEF2)-mediated protein synthesis.


Assuntos
Alcaloides/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Euphorbiaceae/química , Securinega/química , Alcaloides/química , Produtos Biológicos/química , Conformação Molecular
5.
Biophys J ; 120(13): 2679-2690, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34087213

RESUMO

Spin labels based on cinobufagin, a specific inhibitor of the Na,K-ATPase, have proved valuable tools to characterize the binding site of cardiotonic steroids (CTSs), which also constitutes the extracellular cation pathway. Because existing literature suggests variations in the physiological responses caused by binding of different CTSs, we extended the original set of spin-labeled inhibitors to the more potent bufalin derivatives. Positioning of the spin labels within the Na,K-ATPase site was defined and visualized by molecular docking. Although the original cinobufagin labels exhibited lower affinity, continuous-wave electron paramagnetic resonance spectra of spin-labeled bufalins and cinobufagins revealed a high degree of pairwise similarity, implying that these two types of CTS bind in the same way. Further analysis of the spectral lineshapes of bound spin labels was performed with emphasis on their structure (PROXYL vs. TEMPO), as well as length and rigidity of the linkers. For comparable structures, the dynamic flexibility increased in parallel with linker length, with the longest linker placing the spin label at the entrance to the binding site. Temperature-related changes in spectral lineshapes indicate that six-membered nitroxide rings undergo boat-chair transitions, showing that the binding-site cross section can accommodate the accompanying changes in methyl-group orientation. D2O-electron spin echo envelope modulation in pulse-electron paramagnetic resonance measurements revealed high water accessibilities and similar polarity profiles for all bound spin labels, implying that the vestibule leading to steroid-binding site and cation-binding sites is relatively wide and water-filled.


Assuntos
ATPase Trocadora de Sódio-Potássio , Água , Sítios de Ligação , Espectroscopia de Ressonância de Spin Eletrônica , Simulação de Acoplamento Molecular , ATPase Trocadora de Sódio-Potássio/metabolismo , Marcadores de Spin
6.
Fitoterapia ; 152: 104938, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34022295

RESUMO

Two new steroidal glycosides oxystauntoside A (1) and oxystauntoside B (2), together with sixteen known compounds (3-18) were isolated from the 95% ethanol extract of Merrillanthus hainanensis. Their structures were characterized by extensive spectroscopic analysis including NMR and mass spectra and single crystal X-ray crystallography. The absolute configuration of 1 and 2 were further determined by ECD calculations. All of these compounds were isolated from M. hainanensis for the first time. All the fractions and compounds were tested for the anti-inflammatory activity against the TNF-α factor. The ethyl acetate fraction showed the most potent inhibition (71.3%) at 10 µg/mL and compounds 5 (78.9%) and 9 (73.4%) in this fraction with both carboxyl and phenolic hydroxyl groups showed significant inhibition at 10 µM. Our study provided the first scientific report for the medicinal value of M. hainanensis.


Assuntos
Anti-Inflamatórios/farmacologia , Apocynaceae/química , Glicosídeos/farmacologia , Esteroides/farmacologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Anti-Inflamatórios/isolamento & purificação , China , Glicosídeos/isolamento & purificação , Estrutura Molecular , Esteroides/isolamento & purificação
7.
Org Lett ; 23(11): 4499-4504, 2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34032453

RESUMO

Rhodomentosones A and B (1 and 2), two pairs of novel enantiomeric phloroglucinol trimers featuring a unique 6/5/5/6/5/5/6-fused ring system were isolated from Rhodomyrtus tomentosa. Their structures with absolute configurations were elucidated by NMR spectroscopy, X-ray crystallography, and ECD calculation. The bioinspired syntheses of 1 and 2 were achieved in six steps featuring an organocatalytic asymmetric dehydroxylation/Michael addition/Kornblum-DeLaMare rearrangement/ketalization cascade reaction. Compounds 1 and 2 exhibited promising antiviral activities against respiratory syncytial virus (RSV).


Assuntos
Antivirais/química , Myrtaceae/química , Floroglucinol/química , Vírus Sinciciais Respiratórios/química , Biomimética , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Extratos Vegetais/química , Terpenos/química
8.
Proc Natl Acad Sci U S A ; 118(16)2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33850021

RESUMO

For highly specialized insect herbivores, plant chemical defenses are often co-opted as cues for oviposition and sequestration. In such interactions, can plants evolve novel defenses, pushing herbivores to trade off benefits of specialization with costs of coping with toxins? We tested how variation in milkweed toxins (cardenolides) impacted monarch butterfly (Danaus plexippus) growth, sequestration, and oviposition when consuming tropical milkweed (Asclepias curassavica), one of two critical host plants worldwide. The most abundant leaf toxin, highly apolar and thiazolidine ring-containing voruscharin, accounted for 40% of leaf cardenolides, negatively predicted caterpillar growth, and was not sequestered. Using whole plants and purified voruscharin, we show that monarch caterpillars convert voruscharin to calotropin and calactin in vivo, imposing a burden on growth. As shown by in vitro experiments, this conversion is facilitated by temperature and alkaline pH. We next employed toxin-target site experiments with isolated cardenolides and the monarch's neural Na+/K+-ATPase, revealing that voruscharin is highly inhibitory compared with several standards and sequestered cardenolides. The monarch's typical >50-fold enhanced resistance to cardenolides compared with sensitive animals was absent for voruscharin, suggesting highly specific plant defense. Finally, oviposition was greatest on intermediate cardenolide plants, supporting the notion of a trade-off between benefits and costs of sequestration for this highly specialized herbivore. There is apparently ample opportunity for continued coevolution between monarchs and milkweeds, although the diffuse nature of the interaction, due to migration and interaction with multiple milkweeds, may limit the ability of monarchs to counteradapt.

9.
Zhongguo Zhong Yao Za Zhi ; 46(4): 944-950, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33645101

RESUMO

Two new sucrose cinnamates(1 and 2) along with nine known compounds(3-11) were isolated from ethanol extract of Polygonum lapathifolium var. salicifolium by silica gel column chromatography, ODS column chromatography and semi-preparative HPLC. Their structures were elucidated by extensive spectroscopic methods including 1 D-and 2 D-NMR experiments, as well as HR-ESI-MS analysis. Eleven compounds(7 sucrose cinnamates, 3 phenylpropanoids and 1 lactone) were obtained and their structures were identified as(1,3-O-di-p-coumaroyl)-ß-D-fructofuranosyl-(2→1)-α-D-glucopyranoside(1),(1,3-O-di-p-coumaroyl)-ß-D-fructofuranosyl-(2→1)-(6-O-acetyl)-α-D-glucopyranoside(2),(3-O-feruloyl)-ß-D-fructofuranosyl-(2→1)-(6-O-p-coumaroyl)-α-D-glucopyranoside(3), hydropiperoside(4), vanicoside C(5),(1,3-O-di-p-coumaroyl)-ß-D-fructofuranosyl-(2→1)-(6-O-feruloyl)-α-D-glucopyranoside(6), vanicoside B(7),trans-p-hydroxycinnamic acid methyl ester(8), trans-p-hydroxycinnamic acid ethyl ester(9), methyl ferulate(10) and dimethoxydimethylphthalide(11), respectively. Compounds 1 and 2 were two new sucrose cinnamates, and compounds 1-11 were isolated from this plant for the first time. The antioxidant activities of the isolated compounds 1-9 were investigated by an oxygen radical absorbance capacity(ORAC) assay, and all nine compounds were found to show strong antioxidant activities. Among them, compound 6(10 µmol·L~(-1)) was the supreme one in antioxidant activities, with its ORAC value equivalent to(1.60±0.05) times of 50 µmol·L~(-1) Trolox.


Assuntos
Polygonum , Antioxidantes , Cinamatos , Ésteres , Estrutura Molecular , Sacarose
10.
Protein Pept Lett ; 28(5): 533-542, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33172365

RESUMO

BACKGROUND: Human growth hormone (hGH) is the first recombinant protein approved for the treatment of human growth hormone deficiency. However, expression in inclusion bodies and low expression levels are enormous challenges for heterologous expression of hGH in Escherichia coli. OBJECTIVE: To increase the soluble expression of recombinant hGH with correct folding in E. coli. METHODS: We constructed a new recombinant expression plasmid containing the coding sequence of the outer membrane protein A (ompA3) which was used for the expression in Transetta (DE3) E. coli. In order to simplify the purification process and cleavage of recombinant proteins, the fusion sequence should contain hexahistidine-tag (His6) and enterokinase recognition sites (D4K). The effect of different expression conditions on recombinant hGH expression was optimized in flask cultivations. Furthermore, the periplasmic solution containing soluble hGH was purified by Ni-NTA affinity chromatography. Circular dichroism (CD), western blot and mass spectrometry analyses were used to characterize the protein. Moreover, the growth-promoting effect of the purified hGH was also evaluated by cell proliferation assay. RESULTS: High-level expression (800 µg/mL) was achieved by induction with 0.5 mM IPTG at 30°C for 10 hours. The purity of hGH was over 90%. The immunological activity, secondary structure and molecular weight of the purified hGH were consistent with native hGH. The purified hGH was found to promote the growth of MC3T3-E1 cells, and was found to show the highest activity at a concentration of 100 ng/mL. CONCLUSION: Our research provides a feasible and convenient method for the soluble expression of recombinant hGH in E. coli, and may lay a foundation for the production and application of hGH in the industry.


Assuntos
Proteínas da Membrana Bacteriana Externa , Proteínas de Escherichia coli , Escherichia coli , Hormônio do Crescimento Humano , Proteínas Recombinantes de Fusão , Proteínas da Membrana Bacteriana Externa/biossíntese , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/biossíntese , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/isolamento & purificação , Hormônio do Crescimento Humano/biossíntese , Hormônio do Crescimento Humano/química , Hormônio do Crescimento Humano/genética , Hormônio do Crescimento Humano/isolamento & purificação , Humanos , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificação
11.
Phytochemistry ; 181: 112577, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33190100

RESUMO

The new concept that Na/K-ATPase acts as a receptor prompted us to look for new ligands from Callicarpa kwangtungensis Chun. Using column chromatography, an undescribed phenethyl alcohol glycoside, callicarpanoside A, and an undescribed benzyl alcohol glycoside, callicarpanoside B, along with twelve known polyphenols were isolated from Callicarpa kwangtungensis Chun. All the isolated compounds were evaluated for their Na/K-ATPase (NKA) inhibitory activities. Using our NKA technology platform-based screening assay protocols, callicarpanoside B was identified as an undescribed Na/K-ATPase agonist. In particular, the newly identified benzyl alcohol glycoside was found to bind NKA and activate the receptor NKA/Src complex, resulting in the activation of protein kinase cascades. These cascades included extracellular signal-regulated kinases and protein kinase C epsilon, as well as NKA α1 endocytosis at nanomolar concentrations. Unlike the class of cardiotonic steroids, callicarpanoside B showed less inhibition of NKA activity and caused less cellular toxicity. Moreover, callicarpanoside B was found to bind NKA at a different site other than the cardiotonic steroids binding site. Thus, we have identified an undescribed NKA α1 agonist that may be used to enhance the physiological processes of NKA α1 signaling.


Assuntos
Callicarpa , Glicosídeos Cardíacos , Glicosídeos Cardíacos/farmacologia , Glicosídeos/farmacologia , Transdução de Sinais , ATPase Trocadora de Sódio-Potássio/metabolismo
12.
Chem Biodivers ; 17(11): e2000529, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32939944

RESUMO

In this study, bufalin was glycosylated by an efficient chemo-enzymatic strategy. Firstly, 2-chloro-4-nitrophenyl-1-O-ß-D-glucoside (sugar donors) was obtained by chemical synthesis. Then, the glycosylation of the bufalin was achieved with the synthesized sugar donor under the catalysis of two glycosyltransferases (Loki and ASP). Finally, two glycosides, i. e., bufalin-3-O-ß-D-glucopyranoside and bufalin-3-O-[ß-D-glucopyranosyl-(1→2)-ß-D-glucopyranoside)], were obtained by preparative HPLC. Compared to our previously reported sole chemical (total yield 10 % in four steps) or enzymatic methods (30 %), our combined chemo-enzymatic strategy in this article greatly improves the yields of monoglycoside (68 %) and diglycoside (21 %) and decreased the experimental cost (90 %). Furthermore, we tested the water solubility of these glycosides and found that the water solubilities of the two glycosides were 13.1 and 53.7 times of bufalin, respectively. In addition, the inhibitory activity of these glycosides against Na+ , K+ -ATPase were evaluated. The mono-glycosylated compound showed more potent activity than bufalin, while the diglycosylated compound was less potent.


Assuntos
Bufanolídeos/metabolismo , Glicosídeos/metabolismo , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Bufanolídeos/química , Glicosídeos/química , Glicosilação , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Humanos , Conformação Molecular , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , ATPase Trocadora de Sódio-Potássio/metabolismo , Solubilidade , Água/química
13.
Eur J Pharmacol ; 887: 173379, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758567

RESUMO

Bufadienolides are cardioactive C24 steroids with an α-pyrone ring at position C17. In the last ten years, accumulating studies have revealed the anticancer activities of bufadienolides and their underlying mechanisms, such as induction of autophagy and apoptosis, cell cycle disruption, inhibition of angiogenesis, epithelial-mesenchymal transition (EMT) and stemness, and multidrug resistance reversal. As Na+/K+-ATPase inhibitors, bufadienolides have inevitable cardiotoxicity. Short half-lives, poor stability, low plasma concentration and oral bioavailability in vivo are obstacles for their applications as drugs. To improve the drug potency of bufadienolides and reduce their side effects, prodrug strategies and drug delivery systems such as liposomes and nanoparticles have been applied. Therefore, systematic and recapitulated information about the antitumor activity of bufadienolides, with special emphasis on the molecular or cellular mechanisms, prodrug strategies and drug delivery systems, is of high interest. Here, we systematically review the anticancer effects of bufadienolides and the molecular or cellular mechanisms of action. Research advancements regarding bufadienolide prodrugs and their tumor-targeting delivery strategies are critically summarized. This work highlights recent scientific advances regarding bufadienolides as effective anticancer agents from 2011 to 2019, which will help researchers to understand the molecular pathways involving bufadienolides, resulting in a selective and safe new lead compound or therapeutic strategy with improved therapeutic applications of bufadienolides for cancer therapy.


Assuntos
Antineoplásicos/metabolismo , Antineoplásicos/uso terapêutico , Bufanolídeos/metabolismo , Bufanolídeos/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Inibidores da Angiogênese/química , Inibidores da Angiogênese/metabolismo , Inibidores da Angiogênese/uso terapêutico , Animais , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Bufanolídeos/química , Linhagem Celular Tumoral , Humanos , Pró-Fármacos/química , Pró-Fármacos/metabolismo , Pró-Fármacos/uso terapêutico
14.
J Nat Prod ; 83(8): 2410-2415, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32706260

RESUMO

Three rearranged triketone-terpene adducts, myrcaulones A-C (1-3), were isolated from the leaves of Myrciaria cauliflora. Myrcaulones A (1) and B (2) feature a new carbon skeleton with an unprecedented spiro[bicyclo[3.1.1]heptane-2,2'-cyclopenta[b]pyran] core. Myrcaulone C (3) possesses an unusual cyclobuta[6,7]cyclonona[1,2-b]cyclopenta[e]pyran backbone. Their structures with absolute configurations were elucidated by NMR spectroscopy, X-ray diffraction, and electronic circular dichroism calculations. A plausible biogenetic pathway for myrcaulones A-C involving the rearrangement of a triketone unit is also proposed. In addition, myrcaulones A (1) and B (2) exhibited inhibitory effects against tumor necrosis factor-α and nitric oxide generation induced by lipopolysaccharide in RAW 264.7 macrophages.


Assuntos
Cetonas/química , Myrtaceae/química , Terpenos/química , Folhas de Planta/química , Análise Espectral/métodos
15.
ACS Omega ; 5(21): 12251-12258, 2020 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-32548408

RESUMO

Puerarin (PU) is the most abundant isoflavone from the root of Pueraria lobata and exhibits a broad range of pharmacological activities. However, poor water solubility and low bioavailability limit its use. Enzymatic transglycosylation is emerging as a new strategy to improve the pharmacodynamic and pharmacokinetic properties of natural products for drug development. In this study, three PU glucosides (PU-G, PU-2G, and PU-3G) were synthesized by using a cyclodextrin glucanotransferase from Bacillus licheniformis with PU as the acceptor and α-cyclodextrin as the sugar donor. The transglycosylation products were isolated and structurally identified by mass spectrometry and nuclear magnetic resonance. The water solubilities of PU-G, PU-2G, and PU-3G were 15.6, 100.9, and 179.1 times higher than that of PU, respectively. Moreover, the antiosteoporosis activities of these glucosides were tested, and PU-G was found to show much more potent antiosteoporosis activity as compared to the original PU.

16.
Org Lett ; 22(9): 3673-3678, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32319780

RESUMO

Three pairs of Securinega alkaloid epimers with a piperidin-2-yl moiety (1-6) were isolated from Flueggea suffruticosa, and their structures including absolute configurations were definitely characterized. An interconvertible C-2' epimerization process within each pair of epimers was observed. The following comprehensive experimental and theoretical investigations demonstrated an unusual stereochemical inversion mechanism of an N-substituted carbon stereogenic center, which was evidenced to be a protic solvent mediated process involving a tandem 1,4-elimination/1,4-addition as the key step.

17.
J Nat Prod ; 83(5): 1674-1683, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32310646

RESUMO

Six new quassinoids (1-6) were isolated from the roots of Eurycoma longifolia, and their structures with absolute configurations were determined unambiguously by spectroscopic analyses and single-crystal X-ray crystallographic experiments. Compounds 1 and 2 are the first members of a new class of quassinoids with an unusual C26 carbon skeleton. Compound 6 features a C20 cage-like scaffold with an unprecedented densely functionalized 2,5-dioxatricyclo[5.2.2.04,8]undecane core. The discovery of the two C26 quassinoids 1 and 2 has provided firm evidence for the better understanding the biogenetic process from C30 triterpenoid precursors to quassinoids. Compound 5 exhibited significant antifeedant activity on the diamondback moth (DBM) larvae and excellent systemic absorption and accumulated properties in Brassica chinensis.


Assuntos
Eurycoma/química , Inseticidas/farmacologia , Extratos Vegetais/farmacologia , Raízes de Plantas/química , Quassinas/farmacologia , Triterpenos/farmacologia , Animais , Inseticidas/química , Estrutura Molecular , Extratos Vegetais/química , Quassinas/química , Quassinas/isolamento & purificação , Triterpenos/química , Triterpenos/isolamento & purificação
18.
Fitoterapia ; 141: 104470, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31917300

RESUMO

Phytochemical investigations on Physalis. alkekengi L. var. franchetii, a widespread traditional Chinese medicine, led to the isolation and identification of three new sesquiterpenoids physalisitins A-C (1-3). Their structures were elucidated by NMR and HRESIMS analysis, and their absolute configurations were determined by quantum chemical NMR and ECD calculations, as well as by comparing their optical rotation values with those known analogues. All of the isolated compounds were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity. Compounds 1-3 dose-dependently inhibited the COX-2 enzyme with IC50 values of 3.22 ± 0.25, 6.35 ± 0.84, and 11.13 ± 1.47 µM, respectively.


Assuntos
Inibidores de Ciclo-Oxigenase 2/farmacologia , Physalis/química , Sesquiterpenos/farmacologia , Bioensaio , Inibidores de Ciclo-Oxigenase 2/química , Modelos Moleculares , Estrutura Molecular , Plantas Medicinais/química , Sesquiterpenos/química
19.
Org Lett ; 21(23): 9579-9583, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31755722

RESUMO

Two novel phloroglucinol-terpenoid adducts (1 and 2), featuring a rare 2,2,4-trimethyl-cinnamyl-ß-triketone unit, were isolated from the buds of Cleistocalyx operculatus. Their structures with absolute configurations were established by spectroscopic analyses, single-crystal X-ray diffraction, and quantum chemical calculations. Structurally, compound 1 represents a new carbon skeleton possessing a densely functionalized tricyclo[11.3.1.03;8]heptadecane bridged ring system with an unusual bridgehead enol. Compounds 1 and 2 exhibited significant in vitro antiviral activities against respiratory syncytial virus (RSV).


Assuntos
Antivirais/farmacologia , Floroglucinol/farmacologia , Vírus Sinciciais Respiratórios/efeitos dos fármacos , Syzygium , Terpenos/farmacologia , Antivirais/química , Linhagem Celular , Glicoproteínas/metabolismo , Humanos , Estrutura Molecular , Floroglucinol/química , Vírus Sinciciais Respiratórios/metabolismo , Terpenos/química , Proteínas Virais/metabolismo
20.
J Nat Prod ; 82(10): 2818-2827, 2019 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-31550154

RESUMO

Guided by 1H NMR spectroscopic experiments using the aromatic protons as probes, 11 macrocyclic diterpenes (1-11) were isolated from the aerial parts of Euphorbia helioscopia. Their full three-dimensional structures, including absolute configurations, were established unambiguously by spectroscopic analysis and single-crystal X-ray crystallographic experiments. Among the isolated compounds, compound 1 is the third member thus far of a rare class of Euphorbia diterpenes featuring an unusual 5/10 fused ring system, and 2-4 are new jatrophane diterpenes. Based on the NMR data of the jatrophane diterpenes obtained in this study as well as those with crystallographic structures reported in the literature, the correlations of the chemical shifts of the relevant carbons and the configurations of C-2, C-13, and C-14 of their flexible macrocyclic ring were considered. Moreover, the anti-inflammatory activities of 1-11 were investigated by monitoring their inhibitory effects on nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 cells. Compound 1 showed an IC50 of 7.4 ± 0.6 µM, which might be related to the regulation of the NF-κB signaling pathway by suppressing the translocation of the p65 subunit and the consequent reduction of IL-6 and TNF-α secretions.


Assuntos
Anti-Inflamatórios/isolamento & purificação , Diterpenos/isolamento & purificação , Euphorbia/química , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Cristalografia por Raios X , Diterpenos/química , Diterpenos/farmacologia , Espectroscopia de Ressonância Magnética , Camundongos , NF-kappa B/fisiologia , Componentes Aéreos da Planta/química , Células RAW 264.7
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