Natural Prenylflavonoids from Sophora flavescens Root Bark against Multidrug-Resistant Methicillin-Sensitive Staphylococcus aureus Targeting the Membrane Permeability.

The overuse of antibiotics in animal farming and aquaculture has led to multidrug-resistant methicillin-sensitive Staphylococcus aureus (MR-MSSA) becoming a common pathogen in foodborne diseases. Sophora flavescens Ait. serves as a traditional plant antibacterial agent and functional food ingredient. A total of 30 compounds (1-30) were isolated from the root bark of S. flavescens, consisting of 20 new compounds (1-20). In the biological activity assay, compound 1 demonstrated a remarkable inhibitory effect on MR-MSSA, with an MIC of 2 µg/mL. Furthermore, 1 was found to rapidly eliminate bacteria, inhibit biofilm growth, and exhibit exceptionally low cytotoxicity. Mechanistic studies have revealed that 1 possesses an enhanced membrane-targeting ability, binding to the bacterial cell membrane components phosphatidylglycerol (PG), phosphatidylethanolamine (PE), and cardiolipin (CL). This disruption of bacterial cell membrane integrity increases intracellular reactive oxygen species, protein and DNA leakage, reduced bacterial metabolism, and ultimately bacterial death. In summary, these findings suggest that compound 1 holds promise as a lead compound against MR-MSSA.

Targeting cyclin-dependent kinases: From pocket specificity to drug selectivity.

The development of selective modulators of cyclin-dependent kinases (CDKs), a kinase family with numerous members and functional variations, is a significant preclinical challenge. Recent advancements in crystallography have revealed subtle differences in the highly conserved CDK pockets. Exploiting these differences has proven to be an effective strategy for achieving excellent drug selectivity. While previous reports briefly discussed the structural features that lead to selectivity in individual CDK members, attaining inhibitor selectivity requires consideration of not only the specific structures of the target CDK but also the features of off-target members. In this review, we summarize the structure-activity relationships (SARs) that influence selectivity in CDK drug development and analyze the pocket features that lead to selectivity using molecular-protein binding models. In addition, in recent years, novel CDK modulators have been developed, providing more avenues for achieving selectivity. These cases were also included. We hope that these efforts will assist in the development of novel CDK drugs.

Two undescribed constituents from Salvia castanea Diels and evaluation of their cytotoxic activity.

One previously undescribed abietane diterpene alkaloid containing an oxazole ring (1), one unreported abietane diterpene (2), and nine known abietane diterpenes (3-11) were isolated from the roots and rhizomes of Salvia castanea Diels. Their structures and absolute configurations were elucidated by a combination of HRESIMS, 1D and 2D NMR, and ECD. All compounds were evaluated for their cytotoxic activity against several human cancer cell lines (HepG2, A549, H460, MCF7, PC3, and Hela). The results showed that 1 exhibited a moderate cytotoxic effect on HepG2 cells (IC50: 14.22 ± 1.05 µM) and was able to inhibit the cell growth of MCF7 and Hela cells by 35.08% and 47.26% respectively, at a concentration of 20 µM, while other compounds showed low cytotoxic activity.

Diterpenoid glucosides with anti-inflammatory activity from Sigesbeckia glabrescens.

Six previously undescribed diterpenoid glucosides, along with four known compounds, were isolated from the aerial parts of Sigesbeckia glabrescens. The structures and absolute configurations of undescribed compounds were elucidated using extensive spectroscopic techniques, ECD calculations and chemical methods. Compounds 1 and 8 exhibited anti-inflammatory activity against LPS-induced NO production in RAW 264.7 macrophages, with compound 8 demonstrating significant inhibitory activity compared to positive control minocycline, boasting an IC50 value at 14.20 µM.

Characterization of the ADP-ß-D-manno-heptose biosynthetic enzymes from two pathogenic Vibrio strains.

ADP-activated ß-D-manno-heptoses (ADP-ß-D-manno-heptoses) are precursors for the biosynthesis of the inner core of lipopolysaccharide in Gram-negative bacteria. Recently, ADP-D-glycero-ß-D-manno-heptose (ADP-D,D-manno-heptose) and its C-6'' epimer, ADP-L-glycero-ß-D-manno-heptose (ADP-L,D-manno-heptose), were identified as potent pathogen-associated molecular patterns (PAMPs) that can trigger robust innate immune responses. Although the production of ADP-D,D-manno-heptose has been studied in several different pathogenic Gram-negative bacteria, current knowledge of ADP-ß-D-manno-heptose biosynthesis in Vibrio strains remains limited. Here, we characterized the biosynthetic enzymes of ADP-D,D-manno-heptose and the epimerase that converts it to ADP-L,D-manno-heptose from Vibrio cholerae (the causative agent of pandemic cholera) and Vibrio parahaemolyticus (non-cholera pathogen causing vibriosis with clinical manifestations of gastroenteritis and wound infections) in comparison with their isozymes from Escherichia coli. Moreover, we discovered that ß-D-mannose 1-phosphate, but not α-D-mannose 1-phosphate, could be activated to its ADP form by the nucleotidyltransferase domains of bifunctional kinase/nucleotidyltransferases HldEVC (from V. cholerae) and HldEVP (from V. parahaemolyticus). Kinetic analyses of the nucleotidyltransferase domains of HldEVC and HldEVP together with the E. coli-derived HldEEC were thus carried out using ß-D-mannose 1-phosphate as a mimic sugar substrate. Overall, our works suggest that V. cholerae and V. parahaemolyticus are capable of synthesizing ADP-ß-D-manno-heptoses and lay a foundation for further physiological function explorations on manno-heptose metabolism in Vibrio strains. KEY POINTS: • Vibrio strains adopt the same biosynthetic pathway as E. coli in synthesizing ADP-ß-D-manno-heptoses. • HldEs from two Vibrio strains and E. coli could activate ß-D-mannose 1-phosphate to ADP-ß-D-mannose. • Comparable nucleotidyltransfer efficiencies were observed in the kinetic studies of HldEs.

Salvirrane A-F, six undescribed nordrimane sesquiterpene derivatives from Salvia castanea Diels f. tomentosa Stib and their cytotoxic activities.

Six undescribed nordrimane sesquiterpene derivatives, salvirrane A-F (1-6), were isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Comprehensive spectral analysis and a quantum chemical calculation strategy were employed to determine their structures. These compounds represent four previously unreported nordrimane carbon skeletal types in Salvia genus, including 15-nor-drimane, 11,15-di-nor-drimane, 14,15-di-nor-drimane, and 11,14,15-tri-nor-drimane sesquiterpenes. All compounds were evaluated for their cytotoxic activities against several human cancer cell lines (A549, H460, Hep3B, MCF7, PC3, and HeLa). The results showed that 3 exhibited low activity against MCF7 cells (IC50,72.72 ± 6.95 µM) and moderate activity against HeLa cells (IC50, 9.80 ± 0.64 µM). Moreover, the EdU (5-ethynyl-2'-deoxyuridine) assay demonstrates that 3 displays dose-dependent efficacy in suppressing the proliferation of HeLa cells. Network pharmacology and molecular docking technology implied that 3 may potentially bind to Src (proto-oncogene tyrosine-protein kinase) to exert anti-proliferative activity.

(±)-Salvicatone A: A Pair of C27-Meroterpenoid Enantiomers with Skeletons from the Roots and Rhizomes of Salvia castanea Diels f. tomentosa Stib.

(±)-Salvicatone A (1), a C27-meroterpenoid featuring a unique 6/6/6/6/6-pentacyclic carbon skeleton with a 7,8,8a,9,10,10a-hexahydropyren-1 (6H)-one motif, was isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Its structure was characterized by comprehensive spectroscopic analyses along with computer-assisted structure elucidation, including ACD/structure elucidator and quantum chemical calculations with 1H/13C NMR and electronic circular dichroism. Biogenetically, compound 1 was constructed from decarboxylation following [4 + 2] Diels-Alder cycloaddition reaction between caffeic acid and miltirone analogue. Bioassays showed that (-)-1 and (+)-1 inhibited nitric oxide production in lipopolysaccharide-induced RAW264.7 macrophage cells with an IC50 value of 6.48 ± 1.25 and 15.76 ± 5.55 µM, respectively. The structure-based virtual screening based on the pharmacophores in ePharmaLib, as well as the molecular docking and molecular dynamics simulations study, implied that (-)-1 and (+)-1 may potentially bind to retinoic acid receptor-related orphan receptor C to exert anti-inflammatory activities.

Two new sesquiterpenoids with glycosides from the leaves and stems of Schisandra chinensis (Turcz.) Baill.

Two previously undescribed glycosidic bisnorsesquiterpenoids A - B (1 - 2), together with two known compounds (3 - 4), were isolated from the leaves and stems of Schisandra chinensis. Their structures were elucidated by extensive spectroscopic data (1D, 2D NMR, and HRESIMS). The anti-inflammatory activity, ABTS+ radical scavenging activity, and DPPH radical scavenging activity of compounds 1 - 4 were tested. However, all of these compounds showed only weak anti-inflammatory or antioxidant effects.

An integrated network pharmacology approach reveals that Darutigenol reduces inflammation and cartilage degradation in a mouse collagen-induced arthritis model by inhibiting the JAK-STAT3 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Darutigenol (DL) is a natural active product derived from the Chinese herbal medicine Sigesbeckia glabrescens (Makino) Makino. It is administered as a traditional Chinese medicine (TCM) to dispel rheumatism, benefit the joints, and detoxify. However, its potential mechanism in the treatment of rheumatoid arthritis (RA) remains unknown. AIMS OF THE STUDY: The objectives of this research were to determine the effects and elucidate the modes of action of DL on RA-related joint inflammation. MATERIALS AND METHODS: Network pharmacology and molecular docking were used to screen and validate candidate DL targets for RA treatment, respectively. A DBA/1 mouse rheumatoid arthritis model was induced with bovine type II collagen. Intragastric DL administration was followed by the calculation of the clinical arthritis index. A section of the ankle joint was excised and stained and the pathological changes in it were observed. Enzyme-linked immunosorbent assays (ELISA) and western blotting (WB) were used to clarify the mechanisms of DL in RA treatment. RESULTS: DL effectively attenuated the inflammation, mitigated the articular cartilage degradation, and bone erosion, and alleviated the inflammatory joints associated with RA. Network pharmacology screened six key targets of DL while molecular docking revealed that it docked well with its protein targets. The DL treatment group presented with significantly less ankle joint redness and swelling, a lower arthritis index scores and serum and bone marrow supernatant IL-6 levels, more complete ankle joint surfaces, and less synovial inflammation, cartilage degradation, and bone erosion than the collagen-induced arthritis (CIA) group. The DL treatment also substantially downregulated the Janus kinase (JAK)1, JAK3, matrix metalloproteinase (MMP)2, MMP9, and phospho-signal transducer and activator of transcription (p-STAT)3 proteins in the joints. CONCLUSIONS: To the best of our knowledge, the present work was the first to demonstrate that DL has significant anti-inflammatory efficacy and reduces cartilage degradation and bone erosion. It also demonstrated that the anti-RA effect of DL may be explained by its ability to inhibit joint inflammation and reduce articular cartilage degradation through the interleukin (IL)-6/JAK1,3/STAT3 axis and downregulate MMP2 and MMP9. Hence, DL might play a therapeutic role in a mouse RA model.

Chemical constituents from Trillium camschatcense.

Two undescribed polyacetylated 18-norspirostanol saponins, trilliumosides J (1) and 21-deoxyepitrillenoside C (2), a novel resveratrol aneuploid, 3a,3b-dimethoxyhopeachinol B (3) along with four known steroidal saponins (4-7), were isolated from the 70% EtOH extract of the roots and rhizomes of Trillium camschatcense. The structures of isolated compounds were elucidated by spectroscopic analysis and chemical degradation. Compounds 1,3 and 4 had potential cytotoxic activity against MCF-7, with IC50 values 86.38 ± 2.59 µM, 56.20 ± 1.57 µM and 45.70 ± 0.63 µM.

Antiproliferative ent-abietane diterpenoids from Euphorbia fischeriana.

Euphorfinoids M and N (1 and 2), two previously undescribed ent-abietane diterpenoids, together with seven known analogues (3-9), were isolated from the roots of wild Euphorbia fischeriana. Their structures were elucidated by spectroscopic analysis, including extensive NMR, HR-ESIMS, ECD, and comparison with structurally related known analogues. Bioassays against proliferative effects of HeLa cell line showed that compound 1 was the most active with IC50 3.62 ± 0.31 µM.

Euphorfinoids A and B, a pair of ent-atisane diterpenoid epimers from the roots of Euphorbia fischeriana, and their bioactivities.

Euphorfinoids A and B (1 and 2), a pair of ent-atisane diterpenoid epimers with a vicinal 2,3-diol moiety, together with four known analogues (3-6), were isolated from the roots of wild Euphorbia fischeriana. Their structures were elucidated by spectroscopic analysis, including extensive NMR, HR-ESIMS, NMR calculations, X-ray diffraction, and comparison with structurally related known analogues. Our bioassays have established that compound 1 displayed moderate anti-proliferative effects on Hcc1806 cell line with IC50 15.53 ± 0.21 µM, and compound 5 showed remarkable inhibitory effects against AChE with IC50 32.56 ± 2.74 µM by an in vitro screened experiment.

Diterpenoids from Sigesbeckia glabrescens with anti-inflammatory and AChE inhibitory activities.

Fourteen previously undescribed diterpenoids, including seven ent-pimarane-type diterpenoids and seven phytane-type diterpenes, together with five known ones, were isolated from the aerial parts of Sigesbeckia glabrescens. The structures and absolute configurations of undescribed compounds were elucidated based on extensive spectroscopic techniques, ECD calculations, Mo2(OAC)4-induced ECD, Rh2(OCOCF3)4-induced ECD, calculated 13C NMR, and chemical methods. In the anti-inflammatory bioassay, siegetalis H showed potent inhibitory effect on LPS-induced NO production in RAW264.7 murine macrophages with an IC50 value at 17.29 µM. Furthermore, siegetalis H suppressed the protein expression of iNOS and COX-2 in LPS-stimulated RAW264.7 cells. Mechanistically, siegetalis H suppressed the phosphorylation and degradation of IκBα, as well as the activation of the NF-κB signaling pathway. In addition, the AChE inhibition assay displayed that 3-O-acetyldarutigenol had a remarkable inhibitory effect against AChE with an IC50 value at 7.02 µM. Kinetic study on 3-O-acetyldarutigenol indicated that it acted as a mixed-type inhibitor, and the binding mode was explored by molecular docking.

Five previously undescribed compounds from Ajuga lupulina Maxim. and their in vitro activities.

A new biflavone (philonotisflavone-3'''-methyl ether), three diterpenes (lupulin G, lupulin H, lupulin I), a new ecdysteroid (ajugasterone E), and four known compounds were isolated from the whole plant of Ajuga lupulina Maxim. Their structures were determined by spectroscopic analysis, including MS, NMR and ECD spectral data. Compounds 1-3 has DPPH radical scavenging ability, and compound 1 has stronger activity than vitamin C. Compounds 2, 3, 7 and 8 have potential cytotoxic activity against Hela, with IC50 values less than 20.0 µM. Abietane diterpenes 2, 3, 7 and 8 are also found to have NO inhibitory effects with IC50 values less than 40.0 µM.

Euphorfiatnoids A-I: Diterpenoids from the roots of Euphorbia fischeriana with cytotoxic effects.

Nine previously undescribed diterpenoids, euphorfiatnoids A-I, together with seven known diterpenoids, were isolated from the roots of wild Euphorbia fischeriana. Their structures were elucidated by the interpretation of HRESIMS, UV, and NMR data. Their configurations were determined by electronic circular dichroism (ECD) spectroscopy analysis and the structure of euphorfiatnoid A was confirmed by X-ray crystallography. To further understand the antitumor effects of E. fischeriana, we tested the cytotoxicity of these compounds against H460, HepG2, and MCF-7 cell lines in vitro using MTT assays. Euphorfiatnoid B exhibited the most promising inhibitory effect against H460 cells with an IC50 value of 9.97 µM. Euphorfiatnoid A and C also exhibited moderate cytotoxicity against HepG2 cells with IC50 values of 11.64 and 13.10 µM, respectively.

Molecular cloning and characterization of three phenylalanine ammonia-lyase genes from Schisandra chinensis.

Phenylalanine ammonia-lyase (PAL), which catalyzes the conversion from L-phenylalanine to trans-cinnamic acid, is a well-known key enzyme and a connecting step between primary and secondary metabolisms in the phenylpropanoid biosynthetic pathway of plants and microbes. Schisandra chinensis, a woody vine plant belonging to the family of Magnoliaceae, is a rich source of dibenzocyclooctadiene lignans exhibiting potent activity. However, the functional role of PAL in the biosynthesis of lignan is relatively limited, compared with those in lignin and flavonoids biosynthesis. Therefore, it is essential to clone and characterize the PAL genes from this valuable medicinal plant. In this study, molecular cloning and characterization of three PAL genes (ScPAL1-3) from S. chinensis was carried out. ScPALs were cloned using RACE PCR. The sequence analysis of the three ScPALs was carried out to give basic characteristics followed by docking analysis. In order to determine their catalytic activity, recombinant protein was obtained by heterologous expression in pCold-TF vector in Escherichia coli (BL21-DE3), followed by Ni-affinity purification. The catalytic product of the purified recombinant proteins was verified using RP-HPLC through comparing with standard compounds. The optimal temperature, pH value and effects of different metal ions were determined. Vmax, Kcat and Km values were determined under the optimal conditions. The expression of three ScPALs in different tissues was also determined. Our work provided essential information for the function of ScPALs.

Black Tea Reduces Diet-Induced Obesity in Mice via Modulation of Gut Microbiota and Gene Expression in Host Tissues.

Black tea was reported to alter the microbiome populations and metabolites in diet-induced obese mice and displays properties that prevent obesity, but the underlying mechanism of the preventative effect of black tea on high-fat diet (HFD) induced obesity has not been elucidated. Epigenetic studies are a useful tool for determining the relationship between obesity and environment. Here, we show that the water extract of black tea (Lapsang souchong, LS) reverses HFD-induced gut dysbiosis, alters the tissue gene expression, changes the level of a major epigenetic modification (DNA methylation), and prevents obesity in HFD feeding mice. The anti-obesity properties of black tea are due to alkaloids, which are the principal active components. Our data indicate that the anti-obesity benefits of black tea are transmitted via fecal transplantation, and the change of tissue gene expression and the preventative effects on HFD-induced obesity in mice of black tea are dependent on the gut microbiota. We further show that black tea could regulate the DNA methylation of imprinted genes in the spermatozoa of high-fat diet mice. Our results show a mechanistic link between black tea, changes in the gut microbiota, epigenetic processes, and tissue gene expression in the modulation of diet-induced metabolic dysfunction.

Lanostane-type triterpenoids from the mycelial mat of Ganoderma lucidum and their hepatoprotective activities.

Ganoderma lucidum (G. lucidum), a well-known Polyporaceae family fungus, is valued for its edibility and medicinal properties. It is a rich source of active polysaccharides and triterpenoids. However, obtaining material for medicinal purposes relies on artificial cultivation in a greenhouse, which requires large amounts of tree trunk due to the low biomass transformation rate. Therefore, an effective and environment-friendly culture method should be developed and the chemical compounds in the cultured material should be studied. Here we report the isolation and structural elucidation of 10 undescribed lanostane triterpenoids and 21 known compounds from statically cultured mycelial mat of G. lucidum. The hepatoprotective activity of these compounds in H2O2-induced HepG2 cells was evaluated. The structure-activity relationship is discussed. Our results demonstrated that twelve ganoderic acid derivatives possess significant hepatoprotective activities, as judged by suppressed activities of ALT, AST and LDH and increased GSH levels in H2O2-injured HepG2 cells.

[A new norsesquiterpenoid from Schisandra chinensis].

This study investigated the chemical components from the leaves and stems of Schisandra chinensis. Three norsesquiterpenoids were isolated from S. chinensis by various column chromatographies(silica gel, Sephadex LH-20, and MCI), reversed-phase medium-pressure preparative, and semi-preparative high-performance liquid chromatography(HPLC). Their structures were identified based on physicochemical properties, mass spectrometry(MS), nuclear magnetic resonance(NMR), ultraviolet(UV), and electro-nic circular dichroism(ECD) as(3R,4R,5R,6S,7E)-3,4,5,6-tetrahydroxy-7-megastigmen-9-one(1),(3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmen-9-one(2), and(3S,4R,9R)-3,4,9-trihydroxymegastigman-5-ene(3). Compound 1 was a new compound, and its absolute configuration was determined by ECD. Compounds 2 and 3 were isolated from the Schisandra plant for the first time.

New Lanostane-Type Triterpenes with Anti-Inflammatory Activity from the Epidermis of Wolfiporia cocos.

A chemical study on the epidermis of cultivated edible mushroom Wolfiporia cocos resulted in the isolation and identification of 46 lanostane triterpenoids, containing 17 new compounds (1-17). An experimental determination of their anti-inflammatory activity showed that poricoic acid GM (39) most strongly inhibited NO production in LPS-induced RAW264.7 murine macrophages with an IC50 value at 9.73 µM. Furthermore, poricoic acid GM induced HO-1 protein expression and inhibited iNOS and COX2 protein expression as well as the release of PGE2, IL-1ß, IL-6, TNF-α, and reactive oxygen species (ROS) in LPS-induced RAW264.7 cells. Mechanistically, poricoic acid GM suppressed the phosphorylation of the IκBα protein, which prevented NF-κB from entering the nucleus to lose transcriptional activity and inhibited the dissociation of Keap1 from Nrf2, thereby activating Nrf2 into the nucleus to regulate antioxidant genes. Furthermore, the MAPK signaling pathway may play a significant role in poricoic acid GM-induced elimination of inflammation. This work further confirms that lanostane triterpenoids are key ingredients responsible for the anti-inflammatory properties of the edible medicinal mushroom W. cocos.