Chemical constituents of Rubia tibetica Hook. f. from Tibetan medicine and cytotoxic activity evaluation.

Two unprecedented quinone compounds Rubiaxylm A (1) and Rubiaxylm B (2), along with fifteen known anthraquinones (3-17) were isolated and characterized from the roots of Rubia tibetica in Tibetan medicine. Their structures were identified through comprehensive analyses of 1D/2D NMR as well as HR-ESIMS data. Furthermore, all separated compounds were evaluated for their cytotoxic activity on A549, Caco-2, MDA-MB-231 and Skov-3 cell lines. In particular, compound 2 effectively inhibited MDA-MB-231 cells with an IC50 value of 8.15 ± 0.20 µM. Subsequently, the anti-tumor mechanism of 2 was investigated by flow cytometry, JC-1 staining, cell scratching and cell colony. These results indicated that compound 2 could inhibit the proliferation of MDA-MB-231 cells by arresting cells in the G1 phase.

Association between obstructive sleep apnea and low bone mass in adults: a systematic review and meta-analysis.

Introduction: This study aimed to synthesize existing evidence on the potential association between obstructive sleep apnea (OSA) and low bone mass in adults. Methods: Electronic searches of four main databases were performed. The inclusion criteria consisted of observational studies investigating the relationship between OSA and bone mass, osteoporosis, fractures, or bone metabolism markers in adult population. Bone mineral density (BMD) and T score of lumbar and femur neck, incidence of osteoporosis and fractures, bone metabolism marker levels were extracted as primary outcomes. Results: Among the 693 relevant publications, 10 studies consisting of 158,427 participants met with the inclusion and exclusion criteria. Meta-analysis showed a significant lower BMD of lumbar (mean difference (MD) = - 0.03; 95% CI - 0.05, - 0.01; I2 = 46%), femur neck (MD = - 0.06; 95% CI - 0.12, 0.00; I2 = 71%), and a significant lower T score of lumbar (MD = - 0.42; 95% CI - 0.79, - 0.05; I2 = 63%) in the OSA group. The results suggested that both male (odds ratio (OR) = 2.03; 95% CI 1.23, 3.35; I2 = 38%) and female (OR = 2.56; 95% CI 1.96, 3.34; I2 = 0%) had higher risk of osteoporosis in the OSA group. Besides, meta-analysis also showed that bone-specific alkaline phosphatase was significantly lower in OSA patients (MD = - 1.90; 95% CI - 3.48, - 0.32; I2 = 48%). Conclusions: A potential association between OSA and lower bone mass in adults is preliminarily proved. It also seems plausible that both male and female with OSA have a higher risk of osteoporosis. Supplementary Information: The online version contains supplementary material available at 10.1007/s41105-023-00481-1.

Structures and Tumor Cell Lines Proliferation Activities of Triterpenes Isolated from Astilbe grandis.

A total of seven compounds, including four triterpene acids and three triterpene lactones, were isolated from the ethanolic extract of the roots of Astilbe grandis Stapf ex Wils. Two of the triterpene lactones (1-2) were never reported before and compounds 3-5 were isolated for the first time from the plant. The structures of these compounds were all identified by spectroscopic analysis. Compounds 1-2 were analyzed by 2D NMR and their absolute configurations were determined using experimental CD in comparison with calculated ECD values. The structure of compound 1 was also further confirmed by single crystal X-ray diffraction analysis. The cytotoxicity of compounds 1-7 on A549, Caco-2, H460 and Skov-3 tumor cells were all evaluated using CCK-8. They all exhibited positive inhibitory effects on Caco-2 tumor cells with IC50 less than10 µM, while the inhibitory effects on H460 tumor cells were more moderate. Unfortunately, they displayed little apparent cytotoxicity to the other two types of cells.

Brunonianines A-C, C20-diterpenoid alkaloids with cyano group from Delphinium brunonianum Royle.

Cyano tends to have better biological activity, but it is rarely reported in natural products, especially in the C20-diterpene alkaloids. Herein, three unprecedented C20-diterpenoid alkaloids, brunonianines A-C (1-3), possessing rare cyano functional group as well as an atisine backbone constructed from a phenethyl substituent and a tetrahydropyran ring, along with four C19-alkaloids (4-7) and one amide alkaloids (8), were isolated from the whole plant of Delphinium brunonianum Royle. Compounds 1-3 are also the first atisine type diterpenoid alkaloids with cyano group obtained from nature. The structures of the previously undescribed compounds were elucidated by HR-ESI-MS, 1D/2D NMR spectroscopic data and electronic circular dichroism calculations and single-crystal X-ray diffraction. Reasonable speculations have also been made regarding the biogenic synthetic pathways of compounds 1-3. In addition, the inhibitory activity of all compounds was also tested against four tumor lines: A549, Caco-2, H460 and Skov-3, where compound 2 (IC50 2.20 ± 0.21 µM) showed better inhibitory activity against Skov-3 cells than the hydroxycamptothecin. Using flow cytometry, cell staining, migration and invasion analysis, and Western blot, compound 2 was found to arrest cells in the G2/M phase and was able to effectively inhibit cell motility to achieve potent anti-tumor effects. In addition, compound 2 can effectively induce apoptosis by activating the Bax/Bcl-2/Caspase-3 signaling pathway.

An I2-DMSO catalytic manifold enabled aromatization for C-ring editing of podophyllotoxone.

The precise aromatization of the C-ring of podophyllotoxone to access value-added dehydropodophyllotoxin derivatives conventionally requires the use of equivalent amounts of unsustainable oxidants and suffers from inefficiencies. Taking advantage of the hydridic character of the C8 and C8' of podophyllotoxone, we have developed an I2-DMSO catalytic manifold that enables a green and selective dehydrogenative aromatization to overcome these synthetic challenges. An unprecedented dehydrogenative amination of podophyllotoxone derivatives was also realized using aniline as the reaction partner.

Optimization of Neferine Purification Based on Response Surface Methodology and Its Anti-Metastasis Mechanism on HepG2 Cells.

Liver cancer continues to be a focus of scientific research due to its low five-year survival rate. One of its main core issues is the high metastasis of cells, for which there is no effective treatment. Neferine was originally isolated from Plumula nelumbinis and demonstrated to have a good antitumor effect. In order to extract high-purity Neferine in a more efficient and environmentally friendly manner, response surface methodology (RSM) was used to optimize the isolation and purification procedures in this study. The extract conditions of a 7:3 ratio for the eluent of dichloromethane: methanol, 1:60 for the mass ratio of the extract amount: silica gel, and 3 mL/min of the elution flow rate were shown to be the optimal conditions. These conditions resulted in the highest yield of 6.13 mg per 66.60 mg of starting material, with productivity of 8.76% and purity of 87.04%. Compared with the previous methods, this method can prepare Neferine in large quantities more quickly. We subsequently evaluated the antitumor activity of the purified Neferine against HepG2 hepatic cancer cells. The purified Neferine was found to inhibit the proliferation of HepG2 cells through the CCK-8 assay, with an IC50 of 33.80 µM in 24 h, 29.47 µM in 48 h, 24.35 µM in 72 h and 2.78 µM in 96 h of treatment. Neferine at a concentration of 3 µM could significantly inhibit the migration and invasion abilities of the HepG2 cells in vitro. We also explored the mechanism of action of Neferine via Western blot. We showed that Neferine could reduce RhoA expression by effectively inhibiting the phosphorylation of MYPT1, thereby effectively exerting anti-metastasis activity against HepG2 cells. Thus, we have optimized the isolation procedures for highly pure Neferine by response surface methodology (RSM) in this study, and purified Neferine is shown to play an essential role in the anti-metastasis process of liver cancer cells. The Neferine purification procedure may make a wide contribution to the follow-up development of other anti-metastasis lead compounds.

Triterpenoid acids characterized by the oxidation of the C-27-methy from the roots of Astilbe grandis Stapf ex Wils.

Two unprecedented oleane-type triterpenes (5-6) were isolated from the roots of Astilbe grandis Stapf ex Wils, along with four known triterpenes (1-4), all of which were separated from this plant for the first time. The structures of these compounds were elucidated on the basis of spectroscopic analyses especially analysis of 2D NMR data, and the absolute configurations of 5 and 6 were determined by comparison of experimental and calculated ECD data. The structure of 5 was further confirmed by single crystal X-ray diffraction analysis. Compounds 1-6 were evaluated for their in vitro anti-tumor activities on A549, Caco-2, H460 and Skov-3 cells lines. All of the compounds exhibited obvious anti-Caco-2 activity with IC50 values ranging from 1.86 to 4.94 µM, among of them compound 6 also had the apparent effect on A549 cells. In addition, compounds 1, 4 and 5 were evaluated relatively strong inhibitory activity against H460 cells' growth with IC50 values of 5.13 µM, 5.65 µM and 8.85 µM respectively.

A Unique Chemo-photodynamic Antitumor Approach to Suppress Hypoxia via Ultrathin Graphitic Carbon Nitride Nanosheets Supported a Platinum(IV) Prodrug.

Tumor hypoxia severely restrains the efficiency of irreversible O2-consumption photodynamic therapy. The deep hypoxia induced by photodynamic therapy can promote the level of hypoxia inducible factor 1α that participates in many tumor processes and eventually lead to poor therapeutic outcomes. Herein, a chemo-photodynamic antitumor strategy based on ultrathin graphitic carbon nitride nanosheets loaded with a hypoxia-targeting platinum(IV) prodrug is reported. Under low-intensity visible light irradiation, such integrated nanosheets effectively generate reactive oxygen species together with DNA binding platinum species to achieve enhanced antiproliferation efficacy by downregulating HIF-1α under hypoxic conditions.

Switching Over of the Chemoselectivity: I2-DMSO-Enabled α,α-Dichlorination of Functionalized Methyl Ketones.

Precise control of the chemoselectivity of the halogenation of a substrate equipped with multiple nucleophilic sites is highly demanding and challenging. Most reported chlorinations of methyl ketones show poor compatibility or even exclusive selectivity toward electron-rich arene, olefin, and alkyne residues. This is attributed to the direct or in situ employment of electrophilic Cl2/Cl+ species. Here, we reported that, even bearing those competitive residues, methyl ketones can still undergo dichlorination to afford α,α-dichloroketones in a chemo-specific manner. Enabled by the I2-dimethyl sulfoxide catalytic system, in which hydrochloric acid only acts as a nucleophilic Cl- donor, this straightforward dichlorination reaction is safe and operator-friendly and has high atomic economy, giving access to structurally diverse α,α-dichloroketones in good yields and with good functional-group tolerance.

A geniposide-phospholipid complex ameliorates posthyperuricemia chronic kidney disease induced by inflammatory reactions and oxidative stress.

Hyperuricemia is a common metabolic disease and is one of the factors that could induce chronic kidney disease (CKD). Geniposide (GEN) is a typical natural iridoid glucoside compound with a series of biological activities, but the poor bioavailability of GEN limits its clinical application. In this context, the pharmacological activity of the geniposide-phospholipid complex (GEN-PLC) in ameliorating posthyperuricemia CKD was evaluated by in vitro and in vivo experiments in this study. In vitro cell experiments showed that GEN-PLC treatment markedly decreased inflammatory cytokine levels and reactive oxygen species levels compared with those of GEN in uric acid-treated HKC cells. In vivo research results confirmed that a high concentration of uric acid could cause CKD by increasing inflammatory cytokines and reactive oxygen species in hyperuricemic mice. At the same time, GEN-PLC could regulate the PI3K/AKT/NF-κB and Keap1/Nrf2/HO-1 signaling pathways to effectively inhibit the inflammatory response and oxidative stress, thereby ameliorating posthyperuricemia CKD, and the therapeutic effect was better than that of GEN. In addition, the preparation technology of GEN-PLC was optimized, and the physiochemical analysis explained the intermolecular interactions of the two components. Based on the research results, GEN-PLC could enhance the bioavailability of GEN and become a promising candidate for clinical drug development.

Synthesis and biological evaluation of thiazolidine-2-thione derivatives as novel xanthine oxidase inhibitors.

Xanthine oxidase (XO) is a key enzyme in the generation and development of hyperuricemia. Thiazolidine-2-thione, a typical heterocyclic compound, have been widely used in the field of drug synthesis. In this study, a series of novel thiazolidine-2-thione derivatives were synthesized as XO inhibitors, and the XO inhibitory potencies of obtained compounds were evaluated by in vitro enzyme catalysis. The result shown that compound 6k behaved the strongest XO inhibitory activity with an IC50 value of 3.56 µmol/L, which was approximately 2.5-fold more potent than allopurinol. The structure-activity relationship revealed that the phenyl-sulfonamide group was indispensable for thiazolidine-2-thione derivatives to produce XO inhibitory activity. The enzyme inhibition kinetics analyses confirmed that compound 6k exerted a mixed-type XO inhibition. Additionally, the molecular docking results suggested that the 4-fluorophenyl-sulfonyl moiety could interact with Gly260 and Ile264 in the innermost part of the active pocket through 2 hydrogen bonds, while the thiazolidinethione moiety could form two hydrogen bonds with Glu263 and Ser347 in hydrophobic pockets. In summary, the results described above suggested that compound 6k could be a valuable lead compound for the treatment of hyperuricemia as a novel XO inhibitor.

Two new alkaloids from Tibetan medicine of Hypecoum leptocarpum.

Two new alkaloids, leptocarpinine B (1) and corydamine acid (2), with thirteen known alkaloid compounds (3-15), were isolated from Hypecoum leptocarpum. The structures of the isolated compounds were determined based on spectroscopic data analyses, including IR, ESI-MS, 1 D, and 2 D NMR. In addition, all the isolates were evaluated for cytotoxic activities. Compound 6 showed moderate cytotoxicity against human ovarian cancer cell lines (A2780), human cervical cancer cell lines (HeLa), and human hepatocellular carcinomas cell lines (HepG2).[Formula: see text].

Discovery of N-(2-benzyl-4-oxochroman-7-yl)-2-(5-(ethylsulfonyl) pyridin-2-yl) acetamide (b12) as a potent, selective, and orally available novel retinoic acid receptor-related orphan receptor γt inverse agonist.

The nuclear receptor retinoic acid receptor-related orphan receptor γ (RORγ, NR1F3, or RORc) exists in two isoforms, with one isoform (RORγ or RORc1) widely expressed in a variety of tissues, and the expression of the second isoform (RORγt or RORc2) restricted to the thymus and cells of the immune system. RORγt is a key regulator of the development and functions of T-helper 17 (Th17) cells. Clinical proof-of-concept (PoC) with small molecule inverse agonists of RORγt has been achieved with VTP-43742 (Phase II) for the treatment of psoriasis, and pre-clinical PoC for this mechanism has also been established for the treatment of autoimmune diseases. A series of aryl sulfonyl derivatives as novel RORγt inverse agonists were designed and synthesized based on VTP-43742. We conducted structural modifications that improved the activity profile. In pharmacodynamic (PD) studies, oral administration of compound b12 showed robust and dose-dependent inhibition of IL-6 and IL-17A cytokine expression. The ability of compound b12 to reduce the levels of IL-6 and IL-17A in vivo after oral dosing in mice, and a corresponding reduction in skin inflammation further supports the potential of small molecule RORγt modulation as a therapeutic target for the treatment of inflammatory diseases.

Discovery of 2H-chromone-4-one based sulfonamide derivatives as potent retinoic acid receptor-related orphan receptor γt inverse agonists.

Retinoic acid receptor related orphan receptor γt (RORγt), identified as the essential functional regulator of IL-17 producing Th17 cells, is an attractive drug target for treating autoimmune diseases. Starting from the reported GSK2981278 (Phase II), we structurally modified and synthesized a series of 2H-chromone-4-one based sulfonamide derivatives as novel RORγt inverse agonists, which significantly improved their human metabolic stabilities while maintaining a potent RORγt inverse agonist profile. Efforts in reducing the lipophilicity and improving the LLE values led to the discovery of c9, which demonstrated potent RORγt inverse agonistic activity and consistent metabolic stability. During in vivo studies, oral administration of compound c9 exhibited a robust and dose-dependent inhibition of IL-17A cytokine expression and significantly lessened the skin inflammatory symptoms in the mouse imiquimod-induced skin inflammation model. Docking analysis of the binding mode revealed that c9 can suitably occupy the active pocket, and the introduction of the morpholine pyridine group can interact with Leu396, His479, and Cys393. Thus, compound c9 was selected as a preclinical compound for treating Th17-driven autoimmune diseases.

Discovery of Chromane-6-Sulfonamide Derivative as a Potent, Selective, and Orally Available Novel Retinoic Acid Receptor-Related Orphan Receptor γt Inverse Agonist.

Interleukin-17 (IL-17) is a proinflammatory cytokine that plays a dominant role in inflammation, autoimmunity, and host defense. RORγt is a key transcription factor mediating T helper 17 (Th17) cell differentiation and IL-17 production, which is able to activate CD8+ T cells and elicit antitumor efficacy. A series of sulfonamide derivatives as novel RORγt inverse agonists were designed and synthesized. Using GSK2981278 (phase II) as a starting point, we engineered structural modifications that significantly improved the activity and pharmacokinetic profile. In animal studies, oral administration of compound d3 showed a robust and dose-dependent inhibition of the IL-17A cytokine expression in a mouse imiquimod-induced skin inflammation model. Docking analysis of the binding mode revealed that the compound d3 occupied the active pocket suitably. Thus, compound d3 was selected as a clinical compound for the treatment of Th17-driven autoimmune diseases.

Design, synthesis and biological evaluation of cinnamamide-quinazoline derivatives as potential EGFR inhibitors to reverse T790M mutation.

Gatekeeper T790M mutation in EGFR is the most common factor for acquired resistance. Acrylamide-bearing 4-anilinoquinazoline scaffold are powerful irreversible inhibitors for overcoming resistance. In this work, three series of EGFR inhibitors derived from incorporation of cinnamamide into the quinazoline scaffold were designed and synthesized to reverse resistance resulting from insurgence of T790M mutation. SAR studies revealed that methoxy and acetoxy substitutions on the cinnamic phenyl ring were found to elevate the activity. In particular, compound 7g emerged as the most potent derivative against mutant-type H1975 cells, which exhibited comparable activity to osimertinib (0.95 µM) towards H1975 cells with an IC50 value of 1.22 µM. Kinase inhibition studies indicated that 7g showed excellent inhibitory effect on EGFRT790M enzyme, which was 11 times more effective than gefitinib. Besides, selectivity index of 7g toward the EGFRT790M mutant over the EGFRWT is 2.72, hinting its effect of reducing off-target. Mechanism study indicated that 7g induced apoptosis of H1975 cells and arrest the cell cycle at G2/M phase in a dose-dependent manner. Moreover, 7g could significantly inhibit the expression of p-EGFR and its downstream p-AKT and p-ERK in H1975 cells. Molecular docking was also performed to gain insights into the ligand-binding interactions of 7g inside EGFRWT and EGFRT790M binding sites.

A gemcitabine-based conjugate with enhanced antitumor efficacy by suppressing HIF-1α expression under hypoxia.

Hypoxia is one of the unique features of tumor physiology. Hypoxia inducible factor (HIF-1α), as a major transcription factor in response to hypoxia, has been considered as a promising tumor-specific target for anticancer therapy. The formation of a hypoxic microenvironment in tumors can decrease the curative effect of cytotoxic chemotherapeutic drugs. To promote the antitumor efficacy of chemotherapy by suppressing hypoxia, we designed and prepared a novel gemcitabine-based drug conjugate (GEM-5) containing a HIF-1α inhibitor (YC-1). As expected, GEM-5 showed excellent antiproliferative activity (IC50 = 0.03 µΜ under hypoxia) and remarkably induced the apoptosis of A2780 cells in vitro. Additionally, western blot analysis demonstrated that GEM-5 significantly down-regulated the expression of HIF-1α and up-regulated the expression of tumor suppressor p53. More importantly, GEM-5 effectively inhibited tumor growth in the A2780 xenograft mouse model and significantly ameliorated tumor hypoxia in vivo. This novel, simple, and effective strategy for overcoming tumor hypoxia and enhancing the antitumor effect of chemotherapeutic drugs has great potential in cancer therapy.

Isolation, Characterization and Bioactive Properties of Alkali-Extracted Polysaccharides from Enteromorpha prolifera.

Four new purified polysaccharides (PAP) were isolated and purified from the Enteromorpha prolifera by alkali extraction, and further characterization was investigated. Their average molecular weights of PAP-1, PAP-2, PAP-3, and PAP-4 were estimated as 3.44 × 104, 6.42 × 104, 1.20 × 105, and 4.82 × 104 Da, respectively. The results from monosaccharide analysis indicated that PAP-1, PAP-2, PAP-3 were acidic polysaccharides and PAP-4 was a neutral polysaccharide. PAP-1 and PAP-2 mainly consist of galacturonic acid, while PAP-3 and PAP-4 mainly contained rhamnose. Congo red test showed that no triple helical structure was detected in the four polysaccharides. The antioxidant activities were investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), Superoxide, and 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical assay. In vitro antitumor activities were evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. PAP-1 exhibited relatively stronger antioxidant activities among the four polysaccharides in a dose-dependent manner. At a concentration of 1.00 mg/mL, the antioxidant activities of PAP-1 on the DPPH radical scavenging rate, superoxide anion radical scavenging rate, and ABTS radical rate at 1.00 mg/mL were 56.40%, 54.27%, and 42.07%, respectively. They also showed no significant inhibitory activity against MGC-803, HepG2, T24, and Bel-7402 cells. These investigations of polysaccharides provide a scientific basis for the use of E. prolifera as an ingredient in functional foods and medicines.

Anti-proliferative effects of diterpenoids from Sagittaria trifolia L. tubers on colon cancer cells by targeting the NF-κB pathway.

A new labdane-type diterpenoid, ent-19-ol-13-epi-manoyl oxide,19-undecane ester, together with ten known diterpenes, were isolated from the ethanolic crude extract of the fresh tubers of Sagittaria trifolia L. The chemical structures of these compounds were determined by extensive 2-D NMR experiments and by comparison with the data reported in the literature. These compounds showed different inhibitory effects on various human cancer cells. Among these, compound 11 exhibited potential inhibition effects against human colon cancer cells. Moreover, flow cytometry demonstrated that compound 11 arrested the cell cycle at the G1 phase and induced cellular apoptosis, accompanied by mitochondrial membrane potential reduction. Mechanistic studies revealed that treatment with compound 11 inhibited IKKα/ß phosphorylation and IκBα phosphorylation, which subsequently caused the blockage of NF-κB p65 phosphorylation and nuclear translocation. Compound 11 also inhibited the expression of c-Myc, Cyclin D1, and Bcl-2, the downstream targets of NF-κB. Therefore, our findings provided insight into the anticancer components of Sagittaria trifolia L. tubers, which could facilitate their utilization as functional food ingredients.