Sanggenon C and O inhibit NO production, iNOS expression and NF-κB activation in LPS-induced RAW264.7 cells

Modulating Nitric Oxide: Implications for Cytotoxicity and Cytoprotection

Despite the significant progress in the fields of biology, physiology, molecular medicine, and pharmacology; the designation of the properties of nitrogen monoxide in the regulation of life-supporting functions of the organism; and numerous works devoted to this molecule, there are still many open questions in this field. It is widely accepted that nitric oxide (•NO) is a unique molecule that, despite its extremely simple structure, has a wide range of functions in the body, including the cardiovascular system, the central nervous system (CNS), reproduction, the endocrine system, respiration, digestion, etc. Here, we systematize the properties of •NO, contributing in conditions of physiological norms, as well as in various pathological processes, to the mechanisms of cytoprotection and cytodestruction. Current experimental and clinical studies are contradictory in describing the role of •NO in the pathogenesis of many diseases of the cardiovascular system and CNS. We describe the mechanisms of cytoprotective action of •NO associated with the regulation of the expression of antiapoptotic and chaperone proteins and the regulation of mitochondrial function. The most prominent mechanisms of cytodestruction-the initiation of nitrosative and oxidative stresses, the production of reactive oxygen and nitrogen species, and participation in apoptosis and mitosis. The role of •NO in the formation of endothelial and mitochondrial dysfunction is also considered. Moreover, we focus on the various ways of pharmacological modulation in the nitroxidergic system that allow for a decrease in the cytodestructive mechanisms of •NO and increase cytoprotective ones.

The natural compound Sanggenon C inhibits PRRSV infection by regulating the TRAF2/NF-κB signalling pathway

Porcine reproductive and respiratory syndrome (PRRS) is a serious infectious disease and one of the major causes of death in the global pig industry. PRRS virus (PRRSV) strains have complex and diverse genetic characteristics and cross-protection between strains is low, which complicates vaccine selection; thus, the current vaccination strategy has been greatly compromised. Therefore, it is necessary to identify effective natural compounds for the clinical treatment of PRRS. A small molecule library composed of 720 natural compounds was screened in vitro, and we found that Sanggenon C (SC) was amongst the most effective natural compound inhibitors of PRRSV infection. Compared with ribavirin, SC more significantly inhibited PRRSV infection at both the gene and protein levels and reduced the viral titres and levels of protein expression and inflammatory cytokine secretion to more effectively protect cells from PRRSV infection and damage. Mechanistically, SC inhibits activation of the NF-κB signalling pathway by promoting TRAF2 expression, thereby reducing PRRSV replication. In conclusion, by screening natural compounds, we found that SC suppresses PRRSV infection by regulating the TRAF2/NF-κB signalling pathway. This study contributes to a deeper understanding of the therapeutic targets and pathogenesis of PRRSV infection. More importantly, our results demonstrate that SC has potential as a candidate for the treatment of PRRS.

Undescribed chalcone and stilbene constituents from Lysimachia baviensis and their anti-inflammatory effect

The chemical composition and anti-inflammatory activity of the endemic Lysimachia baviensis were investigated for the first time in this study. A phytochemical fractionation of the methanol extract of L. baviensis resulted in the isolation of a new stilbene (bavienside A, 1) and two new chalcone glycosides (baviensides B and C, 2 and 3). Their structures were elucidated via the interpretation of NMR and HRESIMS spectroscopic data. Compounds 1-3 strongly inhibited the production of nitric oxide in LPS-induced RAW264.7 cells with the IC₅₀ values of 6.23, 2.86 and 3.51 μM, respectively. The C-acetylstilbene and carbomethyl chalcone structures in compound 1 and 3 were found for the first time from natural source and could be important markers for chemotaxonomy of Lysimachia baviensis.

Sanggenon C Suppresses Tumorigenesis of Gastric Cancer by Blocking ERK-Drp1-Mediated Mitochondrial Fission

Sanggenon C is a flavonoid extracted from the root bark of white mulberry, which is a traditional Chinese medicine with anti-inflammatory, antioxidative, and antitumor pharmacological effects. In this study, sanggenon C was found to inhibit human gastric cancer (GC) cell proliferation and colony formation, induce GC cell cycle arrest in the G0-G1 phase, and promote GC cell apoptosis. Moreover, sanggenon C was found to decrease the level of mitochondrial membrane potential in GC cells and inhibit mitochondrial fission. Mechanistically, RNA sequencing, bioinformatics analysis, and a series of functional analyses confirmed that sanggenon C inhibited mitochondrial fission to induce apoptosis by blocking the extracellular regulated protein kinases (ERK) signaling pathway, and constitutive activation of ERK significantly abrogated these effects. Finally, sanggenon C was found to suppress the growth of tumor xenografts in nude mice without obvious side effects to the vital organs of animals. This study reveals that sanggenon C could be a novel therapeutic strategy for GC treatment.

Ameliorating Effect of the Total Flavonoids of Morus nigra L. on Prediabetic Mice Based on Regulation of Inflammation and Insulin Sensitization

Prediabetes is a critical stage characterized by insulin resistance. Morus nigra L., an edible plant, is widely used in food and nutritive supplements and exhibits various pharmacological activities; however, its therapeutic effects and mechanisms on prediabetes have rarely been reported. In this research, the major components of total flavonoids of M. nigra L. (TFM) were identified, and TFM treatment was found to reduce prediabetes progressing to type 2 diabetes mellitus (T2DM) from 93.75 to 18.75%. The microbiota and next-generation sequencing combined with western blotting in vivo and in vitro demonstrated that TFM and its components ameliorated insulin resistance mediated by the suppressor of cytokine signaling and protein tyrosine phosphatase 1B, which benefited by maintaining intestinal homeostasis and restraining plasma levels of inflammatory factors. This study confirmed the T2DM prevention effect of TFM and revealed the underlying mechanism, setting the stage for the design of functional foods for diabetes prevention.

Mulberry Diels-Alder-type adducts: isolation, structure, bioactivity, and synthesis

Mulberry Diels-Alder-type adducts (MDAAs) are unique phenolic natural products biosynthetically derived from the intermolecular [4 + 2]-cycloaddition of dienophiles (mainly chalcones) and dehydroprenylphenol dienes, which are exclusively distributed in moraceous plants. A total of 166 MDAAs with diverse skeletons have been isolated and identified since 1980. Structurally, the classic MDAAs characterized by the chalcone-skeleton dienophiles can be divided into eight groups (Types A - H), while others with non-chalcone dienophiles or some variations of classic MDAAs are non-classic MDAAs (Type I). These compounds have attracted significant attention of natural products and synthetic chemists due to their complex architectures, remarkable biological activities, and synthetic challenges. The present review provides a comprehensive summary of the structural properties, bioactivities, and syntheses of MDAAs. Cited references were collected between 1980 and 2021 from the SciFinder, Web of Science, and China National Knowledge Internet (CNKI).

Sanggenon C Stimulates Osteoblastic Proliferation and Differentiation, Inhibits Osteoclastic Resorption, and Ameliorates Prednisone-Induced Osteoporosis in Zebrafish Model

Sanggenon C (SC), which is a natural flavonoid found in the stem bark of Cortex Mori, has been discovered to have the antioxidant, anti-inflammatory, and antitumor properties. However, its effect in osteoporosis has not yet been reported. In this research, the effect of SC on the proliferation of MC3T3-E1 cells was evaluated by using the MTT assay. Alkaline phosphatase (ALP) activity and the mRNA expression of Runx2, Collagen I, OPG, and RANKL were examined. TRAP-positive cell counting and bone resorption pits were adopted to observe the effect of SC on the formation and function of osteoclasts. Next, the mRNA level of TRAP, CTSK, NFATc1, and TRAF6 of osteoclasts were measured by real-time qPCR. In addition, the anti-osteoporosis activity of SC in vivo was evaluated in the zebrafish model. Our study indicated that SC exhibited a significant stimulatory effect on MC3T3-E1 cell proliferation at 1 to 10 μM and caused an increase in ALP activity at 0.3 to 10 μM. It could upregulate the expression of Runx2, Collagen I, and increases the OPG/RANKL ratio. Furthermore, SC was found to inhibit the formation and function of osteoclasts, which is demonstrated by a lower number of TRAP-positive multinuclear cells and a fewer area of bone resorption pits compared to the control group. TRAP, CTSK, and NFATc1 were downregulated in 0.3 to 10 μM SC treated groups. In addition, 3 to 10 μM SC also inhibited the expression of TRAF6 mRNA. When prednisone-induced zebrafish was treated with 0.3, 1, 3, and 10 μM SC, higher mineralization of vertebrate column was discovered in a dose-dependent pattern, which suggests that SC could reverse the bone loss of zebrafish caused by prednisone. In summary, these findings indicated that SC has the potential to prevent or treat osteoporosis.

Sanggenon C protects against cardiomyocyte hypoxia injury by increasing autophagy

Sanggenon C is isolated from Morus alba, a plant that has been used for anti-inflammatory purposes in Oriental medicine. Little is known about the effect of Sanggenon C on cardiomyocyte hypoxia injury. This study, using H9c2 rat cardiomyoblasts, was designed to determine the effects of Sanggenon C on cardiomyocyte hypoxia injury. Inflammatory cytokine levels were measured by reverse transcription-polymerase chain reaction, reactive oxygen species were measured by 2′,7′-dichlorofluorescin diacetate fluorescent probe, autophagy was detected using the LC3II/I ratio and cell apoptosis was detected by TUNEL staining. The molecular mechanisms underlying Sanggenon C-induced cyto-protection were also determined by western blotting, especially the possible involvement of autophagy and AMP-activated protein kinase (AMPK). Results indicated that samples pretreated with different concentrations of Sanggenon C (1, 10 and 100 µM) reduced the expression levels of pro-inflammatory cytokines, including tumor necrosis factor α, interleukin (IL)-1 and IL-6, under hypoxia. The beneficial effects of Sanggenon C were also associated with reduced levels of reactive oxygen species generation and increased levels of antioxidant nitric oxide and superoxide dismutase. Sanggenon C enhanced hypoxia-induced autophagy as evidenced by the increased expression levels of autophagy-associated proteins Beclin and autophagy related 5 as well as the decreased the accumulation of p62, and increased the LC3II/I ratio. Sanggenon C also reduced hypoxia-induced apoptosis as detected by TUNEL staining and the expression of Bcl-2 proteins. The beneficial effects of Sanggenon C were associated with enhanced activation level of AMPKα and suppressed hypoxia-induced mechanistic target of rapamycin (mTOR) and forkhead box O3a (FOXO3a) phosphorylation. The AMPK inhibitor Compound C (CpC) was used, and the anti-apoptotic and pro-autophagy effects of Sanggenon C in response to hypoxia were abolished by CpC. In conclusion, the current study demonstrated that Sanggenon C possessed direct cytoprotective effects against hypoxia injury in cardiac cells via signaling mechanisms involving the activation of AMPK and concomitant inhibition of mTOR and FOXO3a.

[Sanggenon C induces apoptosis of prostate cancer PC3 cells by activating caspase 3 and caspase 9 pathways]

OBJECTIVE

To investigate the effects of Sanggenon C in inducing apoptosis of prostate cancer PC3 cell line and explore the underlying mechanism.

METHODS

The proliferation of PC3 cells treated for 24 h with 1, 5, 20, 50, and 100 µmol/L sanggenon C or treated with 20 µmol/L Sanggenon C for 0, 6, 12, 24 and 48 h was evaluated using MTT assay. Flow cytometry was performed for analysis of apoptosis of PC3 cells after exposure to sanggenon C with different treatment protocols, and the activity of caspase 3 was detected using spectrofluorometry. The inhibitory effect of sanggenon C on PC3 cells pretreated with DMSO, z-DEVD-fmk, z-LEHD-fmk or z-IETD-fmk for 1 h was detected by MTT assay.

RESULTS

Sanggenon C inhibited the proliferation of PC3 cells in a dose- and time-dependent manner (P<0.05 except for 1 µmol/L group) with a 24-h IC₅₀ of 18.76 µmol/L. Sanggenon C at 20 µmol/L caused inhibition rates of PC3 cells of 10.57%, 27.09%, 51.88%, 80.73% and 87.99% after treatment for 6, 12, 24, 48, and 72 h, respectively (P<0.05), and resulted in apoptosis rates of 7.43%, 20.91% and 37.56% at 12 h, 24 h and 48 h, respectively. Sanggenon C significantly increased caspase-3 activity in the cells, and its effect on PC3 cell proliferation was partially reversed by caspase 3 and caspase 9 inhibitors.

CONCLUSION

Sanggenon C can dose-dependently induce growth inhibition and apoptosis of PC3 cells possibly by activating caspase 9 and caspase 3 pathways.

Sanggenon C induces apoptosis of colon cancer cells via inhibition of NO production, iNOS expression and ROS activation of the mitochondrial pathway

Sanggenon C is a well-known, major active agent of the flavonoid derivative of benzopyrone with valuable biological properties, including anticancer, anti-inflammatory, antimicrobial, antiviral, antithrombotic, and immune-modulatory activities. In this study, we investigated the molecular mechanisms by which sanggenon C mediated the induction of cell death in colorectal cancer cells (CRC). Treatment of colorectal cancer cells (LoVo, HT-29 and SW480) with sanggenon C (0, 5, 10, 20, 40 and 80 µM) resulted in inhibited proliferation of colon cancer cells. In addition, Sanggenon C (10, 20, 40 µM) induces apoptosis of HT-29 colon cancer cells as well as the increased ROS generation. Furthermore, treatment with sanggenon C increased the level of intracellular Ca²⁺ and ATP, while inhibited the nitric oxide production via inhibiting inducible nitric oxide synthase expression. This resulted in the activation of mitochondrial apoptosis pathway as evidenced by the decrease in Bcl-2 protein expression. Consistently, the anti-growth and pro-apoptosis effects of sanggenon C on xenograft colon tumor were further confirmed in vivo. Collectively, our results demonstrated sanggenon C induced apoptosis of colon cancer cells by increased reactive oxygen species generation and decreased nitric oxide production, which is associated with inhibition of inducible nitric oxide synthase expression and activation of mitochondrial apoptosis pathway.

Sanggenon C protects against pressure overload‑induced cardiac hypertrophy via the calcineurin/NFAT2 pathway

The effects of Sanggenon C on oxidative stress and inflammation have previously been reported; however, little is currently known regarding the effects of Sanggenon C on cardiac hypertrophy and fibrosis. In the present study, aortic banding (AB) was performed on mice to induce cardiac hypertrophy. After 1 week AB surgery, mice were treated daily with 10 or 20 mg/kg Sanggenon C for 3 weeks. Subsequently, cardiac function was detected using echocardiography and catheter-based measurements of hemodynamic parameters. In addition, the extent of cardiac hypertrophy was evaluated by pathological staining and molecular analysis of heart tissue in each group. After 4 weeks of AB, vehicle-treated mice exhibited cardiac hypertrophy, fibrosis, and deteriorated systolic and diastolic function, whereas treatment with 10 and 20 mg/kg Sanggenon C treatment ameliorated these alterations, as evidenced by attenuated cardiac hypertrophy and fibrosis, and preserved cardiac function. Furthermore, AB-induced activation of calcineurin and nuclear factor of activated T cells 2 (NFAT2) was reduced following Sanggenon C treatment. These results suggest that Sanggenon C may exert protective effects against cardiac hypertrophy and fibrosis via suppression of the calcineurin/NFAT2 pathway.

2-Benzyl-benzofurans from the tubers of Ophiopogon japonicus

Background

The overproduction of nitric oxide (NO) is known to involve in various inflammatory processes. A methanol extract of the tubers of Ophiopogon japonicus was found to strongly inhibit NO production. The present paper deals with the isolation, structural identification and NO inhibitory effect of five compounds isolated from the MeOH extract of O. japonicus tubers.

Results

Three new compounds were elucidated to be (2R)-(4-methoxybenzyl)-5,7-dimethyl-6-hydroxyl-2,3-dihydrobenzofuran (1), 2-(2-hydroxyl-4-methoxy-benzyl)-5-methyl-6-methoxyl-2,3-dihydrobenzofuran (2), and 2-(4-hydroxy-benzyl)-5,6-dihydroxybenzofuran (3). In addition, two known compounds were isolated from a natural source for the first time including 2-(4-methoxy-benzyl)-6,7-dimethoxyl-2,3-dihydrobenzofuran (4), and 2-(4-methoxy-benzyl)-6,7-methylenedioxy-2,3-dihydrobenzofuran (5). The absolute configuration of compound 1 was determined by experimental and calculated circular dichroism spectra. The effects of the isolated compounds on LPS-induced NO production in RAW264.7 cells were evaluated. Compound 1 and 2 showed the inhibitory activity with IC₅₀ values of 11.4 and 29.1 μM, respectively.

Conclusions

The class of 2-benzyl-2,3-dihydrobenzofuran is uncommon in nature. In this work, three such compounds were isolated from O. japonicus. Two of them showed promising anti-inflammatory activity by inhibition of NO production.

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-017-0242-z) contains supplementary material, which is available to authorized users.

Flavonoids from Anoectochilus annamensis and their Anti-inflammatory Activity

One new flavonol diglycoside, 4′,5-dihydroxy-3,3′,7-trimethoxyflavone 4′- O-α-L-rhamnopyranosyl-(1→6)-β-D-glucopyranoside (1), and two known compounds (2–3) were isolated from the methanol extract of Anoectochilus annamensis Aver. aerial parts. The effects were evaluated of all isolated compounds (1–3) on LPS-induced production of the inflammatory mediator nitric oxide (NO) by RAW264.7 cells. 4′,5-Dihydroxy-3,3′,7-trimethoxyflavone (2) was the most active while the addition of a rutinoside at C-4′ (compound 1) decreased the inhibitory activity. This is the first report on the chemical composition and biological activity of A annamensis.

Evaluation of anti-inflammatory activity of prenylated substances isolated from Morus alba and Morus nigra

Chromatographic separation of root extracts of Morus alba and M. nigra led to the identification of the 2-arylbenzofurans moracin C (1), mulberrofuran Y (2), and mulberrofuran H (3), and the prenylated flavonoids kuwanon E (4), kuwanon C (5), sanggenon H (6), cudraflavone B (7), and morusinol (8), and the Diels-Alder adducts soroceal (9), and sanggenon E (10). The cytotoxicity and their antiphlogistic activity, determined as the attenuation of the secretion of TNF-α and IL-1β and the inhibition of NF-κB nuclear translocation in LPS-stimulated macrophages, were evaluated for compounds 1-10.