Discovery of new triterpenoids from Leptopus clarkei and their antiproliferative activity on cancer cells.

Two new triterpenoids (1-2), along with six known analogues (3-8) were obtained from the dried whole plant of Leptopus clarkei. Compound 1 is a 3,4-seco-lupane-type triterpenoid, and compound 2 is a phenylpropanoid-conjugated pentacyclic triterpenoid possessing trans-p-coumaroyl unit attached to oleanane-type skeleton. This is the first report on chemical investigation of the L. clarkei, and the triterpenoid derivatives were found in this plant for the first time. The structures of the new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. Additionally, the isolated compounds were evaluated for theircytotoxicities against four cancer cell lines including HepG2, MCF-7, A549 and HeLa. Notably, compound 2 exhibited the most significant antiproliferative activity with IC50 less than 20 µM for four cancer lines.

Chemical Constituents from the Whole Plants of Limonium sinense and Their in†vitro Anti-inflammatory Activity.

The Yellow River Delta possesses lots of characteristic medicinal plants due to its high salinity and high alkaline environment and Limonium sinense is an iconic plant. However, there are very few studies on L. sinense and its chemical constituents have not been investigated in recent ten years. In the present study, the chemical constituents and bioactivities of L. sinense were fully studied for the first time. UPLC-MS/MS method combined with database comparison identified 109 compounds mainly including flavonoids, alkaloids and polyphenols. In addition, the potential bioactivities of L. sinense were considerated as anti-inflammatory, anti-oxidative, anti-tumor, hepatoprotective and hpyerglycemic activities based on these identified compounds and their related literature. Furthermore, four derivatives of 12-oxo-phytodienoic acid and butenolide including two new ones (1 and 2) were isolated from the whole plants of L. sinense. Their structures, including the absolute configurations, were determined by the analysis of comprehensive spectroscopic data. All isolates were evaluated for their anti-inflammatory activity. Compound 1 exhibited moderate anti-inflammatory activity with IC50 value of 37.5±1.2 µM on NO production level.

Anti-Inflammatory Effects of New Naphthyridine from Sponge Aaptos suberitoides in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and Nrf2 Signaling Pathways.

Two new naphthyridine compounds, 4-methoxycarbonyl-5-oxo-1,6-naphthyridine (1) and 5-methoxycarbonyl-4-oxo-1,6-naphthyridine (2) were obtained from the MeOH extracts of sponge Aaptos suberitoides. Their structures were determined by spectroscopic methods, including HR-ESI-MS, 1D-NMR (1 H-NMR, 13 C-NMR), 2D-NMR (COSY, HSQC, HMBC). The structure of compound 1 was further confirmed via single crystal X-ray diffraction analysis. Compound 1 was found to reduce NO production in LPS-induced RAW 264.7 macrophages with IC50 value of 0.15 mM. In addition, it decreased the mRNA expression levels of pro-inflammatory mediators, such as the tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) in LPS-induced macrophages. It also decreased the protein expression of iNOS and COX-2 in LPS-induced macrophages. Mechanistic studies further revealed that compound 1 inhibited the mitogen-activated protein kinase (MAPK), and activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathways in LPS-induced RAW 264.7 macrophages.

Aaptamine - a dual acetyl - and butyrylcholinesterase inhibitor as potential anti-Alzheimer's disease agent.

CONTEXT: Alzheimer's disease (AD) is a neurodegenerative disorder that affects millions of people worldwide. Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) are promising therapeutic targets for AD. OBJECTIVE: To evaluate the inhibitory effects of aaptamine on two cholinesterases and investigate the in vivo therapeutic effect on AD in a zebrafish model. MATERIALS AND METHODS: Aaptamine was isolated from the sponge Aaptos suberitoides Brøndsted (Suberitidae). Enzyme inhibition, kinetic analysis, surface plasmon resonance (SPR) and molecular docking assays were used to determine its inhibitory effect on AChE and BuChE in vitro. Zebrafish were divided into six groups: control, model, 8 µM donepezil, 5 , 10 and 20 µM aaptamine. After three days of drug treatment, the behaviour assay was performed. RESULTS: The IC50 values of aaptamine towards AChE and BuChE were 16.0 and 4.6 µM. And aaptamine directly inhibited the two cholinesterases in the mixed inhibition type, with Ki values of 6.96 ± 0.04 and 6.35 ± 0.02 µM, with Kd values of 87.6 and 10.7 µM. Besides, aaptamine interacts with the crucial anionic sites of AChE and BuChE. In vivo studies indicated that the dyskinesia recovery rates of 5 , 10 and 20 µM aaptamine group were 34.8, 58.8 and 60.0%, respectively, and that of donepezil was 63.7%. DISCUSSION AND CONCLUSIONS: Aaptamine showed great potential to exert its anti-AD effects by directly inhibiting the activities of AChE and BuChE. Therefore, this study identified a novel medicinal application of aaptamine and provided a new structural scaffold for the development of anti-AD drugs.

Anti-inflammatory Cassane-Type Diterpenoids from the Seed Kernels of Caesalpinia sinensis.

Eighteen cassane diterpenoids, including five new lactam-type (4-8), 12 new lactone-type (1-3 and 9-17), and one known compound (18), were isolated from Caesalpinia sinensis. To our knowledge, this is the first study on the seed kernels of C. sinensis, and cassane derivatives were discovered in this plant for the first time. Their structures including absolute configurations were established by extensive spectroscopic methods complemented with single-crystal X-ray diffraction analyses and ECD calculations. Compounds 4-8 were identified as a group of rare cassane diterpenoids possessing a lactam D-ring instead of a typical lactone moiety. Biological evaluation revealed that compounds 4-6 exhibited effective inhibitory effects on NO production in the LPS-induced RAW 264.7 macrophages, with IC50 values in the range 8.2-11.2 µM. Compound 4 suppressed the excessive production of NO by down-regulating the expression of inducible nitric oxide synthase enzymes (iNOS) and reducing the enzymatic activity of iNOS. Moreover, the intermolecular interaction and binding mode between compound 4 and iNOS were elaborated by conducting a molecular docking study.

Phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum induced cell apoptosis via MAPK and Akt pathways in human hepatocellular carcinoma cells.

Our present and previous phytochemical investigations on Leptopus lolonum have resulted in the isolation of almost 30 phenylpropanoid-conjugated pentacyclic triterpenoids (PCPTs). During the continuous study on PCPTs, this kind of triterpenoid ester is considered as a natural product with low toxicity because of it's widely distribution in natural plants and edible fruits including kiwi fruit, durian, jujube, pawpaw, apple and pear. In the present work, we report the isolation, structural elucidation and cytotoxic evaluation of four new PCPTs (1-4) which obtained from L. lolonum. In addition, the possible biosynthesis pathway for 28-norlupane triterpenoid and potent effect of phenylpropanoid moiety for increasing the cytotxic effect of triterpenoids were also discussed. Among these compounds, compound 1 exhibited the highest cytotoxic effect on HepG2 cells with IC50 value of 11.87 µM. Further flow cytometry and western blot analysis demonstrated that 1 caused G1 cell cycle arrest by up-regulated the expression of phosphorylated p53 protein in HepG2 cells and induced cell apoptosis via MAPK and Akt pathways. These results emphasized the potential of PCPTs as lead compounds for developing anti-cancer drugs.

New phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum with their antiproliferative activities on cancer cells.

Most of Euphorbiaceae plants are considered as folk medicinal plants because of their various pharmacological effects. However, there are eight Leptopus genus plants which belong to Euphorbiaceae have never be investigated. Thus, four Leptopus genus plants were collected to study their chemical constituents and pharmacological activities. In the present work, the cytotoxicities of the extracts of four Leptopus genus plants were evaluated before phytochemical experiments. And nine new phenylpropanoid-conjugated pentacyclic triterpenoids, along with twenty-two known compounds were isolated from the whole plants of Leptopus lolonum. The structures of these new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. All triterpenoids were screened for their cytotoxicities against four cancer cell lines including HepG2, MCF-7, A549 and HeLa. Among these isolates, the triterpenoid with a phenylpropanoid unit showed increasing cytotoxicity on cancer cells, which suggested the importance of the phenylpropanoid moiety.

The bifunctional enzyme, GenB4, catalyzes the last step of gentamicin 3',4'-di-deoxygenation via reduction and transamination activities.

BACKGROUND: New semi-synthetic aminoglycoside antibiotics generally use chemical modifications to avoid inactivity from pathogens. One of the most used modifications is 3',4'-di-deoxygenation, which imitates the structure of gentamicin. However, the mechanism of di-deoxygenation has not been clearly elucidated. RESULTS: Here, we report that the bifunctional enzyme, GenB4, catalyzes the last step of gentamicin 3',4'-di-deoxygenation via reduction and transamination activities. Following disruption of genB4 in wild-type M. echinospora, its products accumulated in 6'-deamino-6'-oxoverdamicin (1), verdamicin C2a (2), and its epimer, verdamicin C2 (3). Following disruption of genB4 in M. echinospora ΔgenK, its products accumulated in sisomicin (4) and 6'-N-methylsisomicin (5, G-52). Following in vitro catalytic reactions, GenB4 transformed sisomicin (4) to gentamicin C1a (9) and transformed verdamicin C2a (2) and its epimer, verdamicin C2 (3), to gentamicin C2a (11) and gentamicin C2 (12), respectively. CONCLUSION: This finding indicated that in addition to its transamination activity, GenB4 exhibits specific 4',5' double-bond reducing activity and is responsible for the last step of gentamicin 3',4'-di-deoxygenation. Taken together, we propose three new intermediates that may refine and supplement the specific biosynthetic pathway of gentamicin C components and lay the foundation for the complete elucidation of di-deoxygenation mechanisms.

New cassane-type diterpenoids from kernels of Caesalpinia bonduc (Linn.) Roxb. and their inhibitory activities on phosphodiesterase (PDE) and nuclear factor-kappa B (NF-κB) expression.

In this paper, chemical investigation on the chloroform soluble fraction of seed kernels of Caesalpinia bonduc resulted in the isolation of five new cassane diterpenoids: norcaesalpinin O (1), norcaesalpinin P (2), caesalpinin MQ (3), caesall O/P (4/5) and seven known compounds (6-12). Compounds structures were elucidated by 1H NMR, 13C NMR, 2D NMR, HR-MS and ECD (electronic circular dichroism) spectral analysis. The characters for new compounds with the presence of an aromatized C ring or demethyl group at C-17 position in the structures were found. By means of bioactive screenings, the inhibitory effect on type-4 phosphodiesterase (PDE4, the target protein of asthma disease) and nuclear factor-kappa B (NF-κB) expression were valued. Compound 1 was found to exhibit moderate inhibitory activity on PDE4 and much better binding affinity than other structures by docking studies for interaction analyzing. Compounds 6, 10 and 11 displayed considerable inhibitory strength against NF-κB expression with inhibitory ratio 48.6%, 42.9% and 37.1% at 10 µM, respectively. The isolation of cassane-type diterpenoids with anti-inflammation activity from C. bonduc implied that this plant might be a good source for anti-inflammation agents finding.

Discovery of 1H-pyrazolo[3,4-b]pyrazine derivatives as selective allosteric inhibitor of protein tyrosine phosphatase SHP2 for the treatment of KRASG12C-mutant non-small cell lung cancer.

The high expression or mutation of SHP2 can induce cancer, so targeting SHP2 has become a new strategy for cancer treatment. In this study, we used the previously reported SHP2 allosteric inhibitor IACS-13909 as a lead drug for structural derivation and modification, and synthesized three SHP2 inhibitors. Among them, 1H-pyrazolo[3,4-b]pyrazine derivative 4b was a highly selective SHP2 allosteric inhibitor, with an IC50 value of 3.2 nM, and its inhibitory activity was 17.75 times than that of the positive control IACS-13909. The cell proliferation experiment detected that compound 4b would markedly inhibit the proliferation of various cancer cells. Interestingly, compound 4b was highly sensitive to KRASG12C-mutant non-small cell lung cancer NCI-H358 cells, with an IC50 value of 0.58 µM and its antiproliferative activity was 4.79 times than that of IACS-13909. Furthermore, the combination therapy of compound 4b and KRASG12C inhibitor sotorasib would play a strong synergistic effect against NCI-H358 cells. The western blot experiment detected that compound 4b markedly downregulated the phosphorylation levels of ERK and AKT in NCI-H358 cells. Molecular docking study predicted that compound 4b bound to the allosteric site of SHP2 and formed H-bond interactions with key residues Thr108, Glu110, Arg111, and Phe113. In summary, this study aims to provide new ideas for the development of SHP2 allosteric inhibitors for the treatment of KRASG12C mutant non-small cell lung cancer.Communicated by Ramaswamy H. Sarma.

Chemical constituents from the seeds of Cullen corylifolium and their inhibitory activity on diacylglycerol acyltransferase.

A large number of extracts of medicinal plants or natural products shows beneficial to combat obesity. In the present work, a new flavonoid named (2S,1″R,2″R)-4'-hydroxy-7-methoxy-6-(1,2,3-trihydroxy-3-methyl-butyl)-flavanone (1), along with seven known compounds (2-8) were isolated from the seeds of Cullen corylifolium. Their structures, including the absolute configurations, were determined by the analysis of comprehensive spectroscopic data and computational calculation methods. All isolates were evaluated for their diacylglycerol acyltransferase (DGAT) inhibitory activity. Compounds 1-4 exhibited different level of DGAT1 inhibitory activity with IC50 values ranging from 28.2 ± 1.1 to 127.3 ± 1.9 µM. In addition, 45 flavonoids which be evaluated for DGAT inhibitory activity were summarised and potential structure-activity relationships were discussed.

Two new cassane-type diterpenoids from the seed kernels of Caesalpinia bonduc (Linn.) Roxb. and their anti-inflammatory activity.

In this study, phytochemical investigation on the chloroform soluble fraction of seed kernels of Caesalpinia bonduc led to the isolation of two new cassane-type diterpenoids, norcaesalpinin Q (1) and caesalpinin MR (2), together with seven known compounds (3-9). The structures of the new compounds were elucidated on the basis of extensive NMR spectroscopic and mass spectrometric analyses, and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. All compounds were evaluated for inhibitory effects against NO production of RAW264.7 cells induced by LPS, and compounds 5, 7 and 8 could inhibited the production of NO at the concentration of 50 µM.

Cytochalasins from coastal saline soil-derived fungus Aspergillus flavipes RD-13 and their cytotoxicities.

Chemical investigation of coastal saline soil-derived fungus Aspergillus flavipes RD-13 led to the isolation of two new seco-cytochalasins (1) and (2) along with nine known analogs. Their structures were elucidated by comprehensive spectral analysis, and the absolute configurations of these two new ones were determined through Rh2(OCOCF3)4-induced CD experiment and chemical interconversions. Moreover, the absolute configuration of a known compound named cytochalasins Z18 (3) was also determined for the first time. Structurally, compounds 1, 2 and 3 were the open ring derivatives of compounds 5, 8, and 4, respectively. All compounds were evaluated for their cytotoxic activities on A549, H1299 and H520 cells and 4 exhibited the strongest inhibitory activities towards the above cell lines with IC50 values of 0.15, 0.23 and 0.43 µg/mL, respectively. Preliminary structure-activity relationship analysis suggested the importance of macrocyclic ring in cytochalasins to confer cytotoxicity.

Acid-catalyzed transformation of cassane diterpenoids from Caesalpinia bonduc to aromatic derivatives.

Transformations of cassane diterpenoids from Caesalpinia bonduc into aromatic derivatives, either in CDCl3 or in CHCl3 irradiated with UV light or catalyzed by AlCl3, were described. Caesalmin C (2) was hydrolyzed with Na2CO3 upon refluxing in MeOH to yield compound 1. Dissolving compound 1 with CDCl3 resulted in an unexpected aromatization process of a C ring to obtain 1a, and aromatic derivatives 6-acetoxy-3-deacetoxycaesaldekarin e (2a), caesall A (3a), caesaldekarin e (5a), caesalpinin MC (5b), 2-acetoxycaesaldekarin e (6a) and new compound 6b could be obtained from corresponding cassane diterpenoids (2-8) under the same conditions. Furthermore, the photochemical reactions of cassane diterpenoids 1-8 occurring in CHCl3 also yielded aromatic derivatives 1a, 2a, 3a, 5a, 6a, new compounds 2b and 3b, and 17-norcassane diterpenoids norcaesalpinin MC (2c) and caesalmin J (3c). In addition, cassane diterpenoids 1-8, treated with AlCl3 in CHCl3 or CH2Cl2, gave the same results in CDCl3 and with even shorter reaction time. The role of AlCl3 in the aromatization of 1 has been explained by DFT calculations.

New pentacyclic triterpenoids isolated from Leptopus chinensis and their hepatoprotective activities on tert-butyl hydroperoxide-induced oxidative injury.

Eight unknown pentacyclic triterpenoids (1-4 and 8-11), along with eight known analogues (5-7 and 12-16) have been first isolated from the dried whole plant of Leptopus chinensis. The structures of the new compounds were determined by comprehensive spectroscopic methods, including 1D and 2D NMR, as well as HRESIMS measurements. Meanwhile, the hepatoprotective activities of the isolated compounds were preliminarily evaluated, and the results indicated that compounds 2, 5 and 16 possess potent protective effects on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in vitro, and further study revealed that 16 significantly alleviates t-BHP-induced hepatotoxicity by effectively improving cell viability and decreasing reactive oxygen species (ROS) generation and the cell apoptosis rate in HepG2 cells.

New sesquiterpenoid glycoside from the rhizomes of Atractylodes lancea.

Six sesquiterpenoids and four lignans (1-10) were isolated from the n-BuOH extract of the rhizomes of Atractylodes lancea. Among them, the new sesquiterpenoid glycoside named (4 R, 5S, 7R)-hinesolone-11-O-ß-ᴅ-glucopyranoside (1), along with three known compounds (2-4) were first obtained from this genus. All the isolates were elucidated by spectroscopic analyses and chemical methods, and the absolute configurations were assigned by electronic circular dichroism spectroscopy technique. In addition, the cytotoxic bioassay of compound 1 was evaluated and results showed it had no significant antitumor activity against human cancer cell lines MCF-7, HepG-2 and Hela.

A new sesquiterpenoid glycoside from Saussurea involucrata.

Saussurea involucrata, known for the abundant bioactive components, is a precious traditional Chinese medicine. In this study, a novel guaiane sesquiterpenoid glycoside named (1R, 5R, 6R, 7R, 8S, 11S)-11, 13-dihydrodehydrocostuslactone-8-O-6'-2''(E)-butenoyl-ß-D-glucopyranoside (1), together with seven known compounds (2-8) were isolated from the dried aerial part of S. involucrata. Their structures were elucidated by spectroscopic and physico-chemical analyses. The antioxidant and anti-inflammatory activities of compound 1 were investigated. And compound 1 showed weak radical scavenging activity and low inhibitory activity on nitric oxide (NO) production.

The dietary freeze-dried fruit powder of Actinidia arguta ameliorates dextran sulphate sodium-induced ulcerative colitis in mice by inhibiting the activation of MAPKs.

In this study, we aimed at investigating the antiinflammatory activity of the freeze-dried fruit powder of Actinidia arguta (FAA) on dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in mice and the effect of its extract on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. For pharmacodynamic studies, the oral administration of FAA (300 or 600 mg kg-1) could decrease the disease activity index (DAI), reduce the incidence of colon and spleen edemas (caused by inflammation), and alleviate the pathological changes in UC. For research involving biochemical indicators, FAA could decrease the expression of inflammatory markers (such as myeloperoxidase (MPO)) and attenuate the oxidative stress levels. ELISA results revealed that the expressions of proinflammatory cytokines (IL-1ß, IL-6, and TNF-α) were downregulated by FAA. Furthermore, the expression levels of the inflammation-induced activation of p38, JNK, and ERK were decreased by FAA. Hence, it was concluded that FAA could alleviate the UC symptoms in mice and the inflammatory response of macrophages via the MAPK signal pathway. Overall, FAA might have the potential to treat UC when used as a dietary supplement.

Diacylglycerol acyltransferase 1 (DGAT1) inhibition by furofuran lignans from stems of Acanthopanax senticosus.

Two new furofuran lignans were isolated from the stems of Acanthopanax senticosus, along with seven known compounds. Their structures were all determined by spectroscopic analyses and chemical methods. All the isolates were evaluated for in vitro inhibitory activity against DGAT1 and DGAT2. Compounds 1 and 2 were found to exhibit selective inhibitory activity on DGAT1 with IC50 values 89.5 ± 1.5 and 57.5 ± 1.3 µM, respectively.

Four new sesqui-lignans isolated from Acanthopanax senticosus and their diacylglycerol acyltransferase (DGAT) inhibitory activity.

Four new sesqui-lignans, (7R, 7'R, 7″S, 8S, 8'S, 8″S)-4',5″-dihydroxy-3,5,3',4″-tetramethoxy-7,9':7',9-diepoxy-4,8″-oxy-8,8'-sesquineo-lignan-7″,9″-diol (1), (7R, 7'R, 7″S, 8S, 8'S, 8″S)-4',3″-dihydroxy-3,5,3',5',4″-pentamethoxy-7,9':7',9-diepoxy-4,8″-oxy-8,8'-sesquineo-lignan-7″,9″-diol (2), (7R, 7'R, 7″S, 8S, 8'S, 8″S)-3',4″-dihydroxy-3,5,4',5″-tetramethoxy-7,9':7',9-diepoxy-4,8″-oxy-8,8'-sesquineo-lignan-7″,9″-diol (3) and acanthopanax A (7) together with three known compounds (4-6) were isolated from the EtOAc-soluble extract of Acanthopanax senticosus. Their structures were elucidated on the basis of spectroscopic and physicochemical analyses. All the isolates were evaluated for in vitro inhibitory activity against DGAT1 and DGAT2. Among them, compounds 1-6 were found to exhibit selective inhibitory activity on DGAT1 with IC50 values ranging from 61.1 ± 1.3 to 97.7 ± 1.1 µM and compound 7 showed selective inhibition of DGAT2 with IC50 value 93.2 ± 1.2.