Identification and in vitro Characterization of Novel Antidiabetic Peptides Released Enzymatically from Peanut Protein.

Bioactive peptides derived from proteins found in various foods provide significant health benefits, including regulating blood sugar levels by inhibiting carbohydrate-hydrolyzing enzymes. Hydrolysates of peanut protein were prepared using alcalase (AH) or trypsin (TH) to generate antidiabetic peptides with high activity against α-amylase (IC50 of 6.46 and 5.71 mg/mL) and α-glucosidase (IC50 of 6.30 and 5.57 mg/mL), as well as antiradical activity to scavenge DPPH• (IC50 of 4.18 and 3.12 mg/mL) and ABTS•+ (IC50 of 2.87 and 2.56 mg/mL), respectively. The bioactivities of hydrolysates were greatest in the ultrafiltration-generated F3 fraction (< 3 kDa). The most active fraction was TH-F3, which was purified by gel filtration chromatography to generate sub-fractions (SF). With IC50 values of 1.05 and 0.69 mg/mL, the F3-SF8 fraction was the most effective at inhibiting the activity of α-amylase and α-glucosidase, respectively. This fraction was further purified using RP-HPLC to generate sub-subfractions (SSF), the most active of which were F3-SF8-SSF9 and SSF10. The peptide sequences F3-SF8-SSF9 and SSF10 were determined using LC-MS/MS. Two novel antidiabetic peptides with the potential to inhibit α-amylase and α-glucosidase were identified, with the sequences Asp-Trp-Arg (476.22 Da, IC50 of 0.78, and 0.35 mg/mL) and Phe-Tyr (329.15 Da, IC50 of 0.91, and 0.41 mg/mL). These results suggest that peptides derived from peanut protein are attractive natural ingredients for diabetes management applications.

Dietary γ-mangostin triggers immunogenic cell death and activates cGAS signaling in acute myeloid leukemia.

Immunogenic cell death (ICD), one of cell-death types through release of damage-associated molecular patterns from dying tumor cells, activates tumor-specific immune response and elicits anti-tumor immunity by traditional radiotherapy and chemotherapy. However, whether natural products could induce ICD in leukemia is not elucidated. Here, we report dietary γ-mangostin eradicates murine primary leukemic cells and prolongs the survival of leukemic mice. As well, it restrains primary leukemic cells and CD34+ leukemic progenitor cells from leukemia patients. Strikingly, γ-mangostin attenuates leukemic cells by inducing ICD as characterized by expression of HSP90B1, ANXA1 and IL1B. Additionally, γ-mangostin accelerates cytoplasmic chromatin fragments generation, promoting DNA damage response, and enhances cGAS activation, leading to up-regulation of chemokines. Meanwhile, it induces HDAC4 degradation and acetylated histone H3 accumulation, which promotes chemokines transcription. Ultimately, CD8+ T cell is activated and recruited by γ-mangostin-induced chemokines in the microenvironment. Our study identifies γ-mangostin triggers ICD and activates cGAS signaling through DNA damage response and epigenetic modification. Therefore, dietary γ-mangostin would act as a potential agent to provoke anti-tumor immunity in the prevention and treatment of leukemia.

Antibacterial sesquiterpenes from the stems and roots of Thuja sutchuenensis.

Eight new sesquiterpenes with diverse skeletons involving four cuparenes, denominated thujasutchins F-I (1-4), one eudesmane and one cedrol, named thujasutchin J (5) and thujasutchin K (6), as well as two thujopsenes thujasutchins L-M (7-8) together with three known congener compounds (9-11) were isolated from EtOAc soluble fraction of ethanolic extract of the stems and roots of Thuja sutchuenensis. Their structures including absolute configurations were unambiguously established by extensive interpretation of the NMR and mass spectroscopic data, X-ray diffractions, and ECD measurements powered by molecular calculations. The biological assays disclosed that 5 and 9 displayed potent inhibitory effect against Staphylococcus. aureus (CMCC 26003), methicillin-resistant Staphylococcus aureus (JCSC 4744), Bacillus cereus (ATCC 10876), and Staphylococcus epidermidis (ATCC 12228) with MICs ranging from 6.25 to 25 µg/mL.

Callistemonols A and B, Potent Antimicrobial Acylphloroglucinol Derivatives with Unusual Carbon Skeletons from Callistemon viminalis.

A phytochemical investigation on the leaves of Callistemon viminalis resulted in the isolation of two unusual compounds, callistemonols A (1) and B (2). Callistemonol A (1) possesses a novel skeleton of a furan ring fusing both an α,ß-triketone and a phloroglucinol unit, while callistemonol B (2) is an acylphloroglucinol derivative featuring two methyl substituents on a five-membered ring and an isovaleryl side chain. Their structures were fully characterized on the basis of extensive spectroscopic analysis, including 1D and 2D NMR parameters, as well as the IR and HRESIMS data. Callistemonol A (1) represents an example of a natural dibenzofuran with two phenyl moieties, and a plausible biogenetic pathway to generate this novel dibenzofuran through a C-C bond-forming radical SAM enzyme is proposed. Moreover, antimicrobial assays, in conjunction with time-killing and biophysical studies, revealed that 1 and 2 exert potent bactericidal activities against a panel of methicillin-resistant pathogenic microbes.

Two new 12-membered macrolides from the endophytic fungal strain Cladosprium colocasiae A801 of Callistemon viminalis.

Two new polyketide metabolites, the 12-membered macrolides 4-hydroxy-12-methyloxacyclododecane-2,5,6-trione (1) and 12-methyloxacyclododecane-2,5,6-trione (2), were isolated from the endophytic fungal strain Cladosprium colocasiae A801 of the plant Callistemon viminalis, together with five known derivatives. Their structures were fully characterized by means of detailed spectroscopic analysis for new structures, and in comparison with published data for known compounds. The antibacterial, cytotoxic, and α-glucosidase inhibitory activities of the new compounds 1 and 2 were evaluated.

Three new kavalactone dimers from Piper methysticum (kava).

Three new dimeric kavalactones, designated as diyangonins A-C (1-3), along with two known analogs were isolated from the roots of Piper methysticum. Their structures were elucidated by means of extensive analysis of their 1D, 2D NMR, and mass spectroscopic data. All these dimers possess a skeleton featuring a cyclobutane ring connecting two kavalactone units in head-to-tail or head-to-head mode. Compounds 1-5 were evaluated for their cytotoxic activities against human tumor cell lines.

Two new ent-kaurane diterpenes from the stems of Eurya chinensis.

Two new ent-kaurane diterpenes (1-2), together with five known analogs, were isolated from the stems of Eurya chinensis. The structures of new compounds were established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. Compound 3 exhibited noticeable anti-inflammatory activity as denoted by inhibiting LPS-induced nitric oxide (NO) production in RAW264.7 cells with an IC50 value of 7.82 µM. Compound 4 showed potent cytotoxic activity against human cancer cell lines NCI-H46, HepG2 and SW480 with IC50 values ranging from 7.45 to 8.54 µM.

Anti-inflammatory and antimicrobial coumarins from the stems of Eurya chinensis.

Two new coumarins, named (±)-euryacoumarin A (1) and 6-demethylobtusinin (2), and one new natural coumarin, named euryacoumarin B (3), along with two known compounds, scopoletin (4) and obtusinol (5), were isolated from the stems of Eurya chinensis. Their structures were elucidated by means of extensive spectroscopic methods and comparison with data reported in the literatures. Compound 1 exhibited significant inhibition of LPS-induced nitric oxide (NO) production in RAW264.7 cells with IC50 value of 35.64 ± 1.73 µM, and showed marginal antibacterial activities against Bacillus subtilis and B. cereus with MIC values of 50.59 ± 2.12 and 35.42 ± 0.96 µM, respectively.

Rhodomentones A and B, novel meroterpenoids with unique NMR characteristics from Rhodomyrtus tomentosa.

Two novel meroterpenoids, rhodomentones A and B bearing an unprecedented caryophyllene-conjugated oxa-spiro[5.8] tetradecadiene skeleton, were isolated from the leaves of Rhodomyrtus tomentosa. Their structures with unique NMR characteristics were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, quantum molecular calculation, chemical transformation as well as total synthesis.

Antimicrobial acylphloroglucinols from the leaves of Rhodomyrtus tomentosa.

Phytochemical study on the leaves of Rhodomyrtus tomentosa resulted in the isolation of fourteen compounds including a new acylphloroglucinol, named tomentosone C (1), and a new flavonol glycoside, namely myricetin-3,7,3'-trimethyl ether-5'-O-ß-glucopyranoside (2). Their structures were characterized by spectral data interpretation for new structures and in comparison with published data for known compounds. The antimicrobial activity evaluation revealed that 1 and the known acylphloroglucinol rhodomyrtone (3) exhibited significant antimicrobial activity with MIC 3.66 and 1.83 µg ml(-1), respectively, toward Staphylococcus aureus, responsible for the antimicrobial activity observed with the n-hexane and EtOAc-soluble fraction of the ethanol extract of R. tomentosa leaves.

[Chemical Constituents from Mitrasacme pygmaea].

Objective: To study the chemical constituents from Mitrasacme pygmaea. Methods: The compounds were isolated and purified by column chromatography and their structure were identified by NMR and MS,and comparison spectral data with literature. Results: Eleven compounds were isolated and identified as tricin-7-O-ß-D-glucopyranoside( 1),massonianoid A( 2),kaempferol( 3),cinnamic acid( 4),quercetin( 5),tiliroside( 6),tricin( 7),ß-sitosterol( 8),adenosine( 9),α-tocopherolquinone( 10)and ß-daucosterol( 11). Conclusion: All the compounds are isolated from this genus for the first time.

[Chemical Constituents from Periploca forrestii].

Objective: To study the chemical constituents from Periploca forrestii. Methods: The constituents were separated by column chromatography and their structures were elucidated by spectroscopic methods. Results: Seven compounds were isolated from Periploca forrestii and identified as wogonin( 1),negletein( 2),vanilline( 3),isovanilline( 4),periplocoside L( 5),ß-sitosterol( 6) and ß-daucosterol( 7). Conclusion: Compounds 1 and 2 are obtained from this genus for the first time,and compounds 3 ~ 5 are isolated from this plant for the first time.

A Halogen-Containing Stilbene Derivative from the Leaves of Cajanus cajan that Induces Osteogenic Differentiation of Human Mesenchymal Stem Cells.

A new natural halogen-containing stilbene derivative was isolated from the leaves of Cajanus cajan (L.) Millsp. and identified as 3-O-(3-chloro-2-hydroxyl-propanyl)-longistylin A by comprehensive spectroscopic and chemical analysis, and named cajanstilbene H (1). It is the first halogen-containing stilbene derivative found from plants. In human mesenchymal stem cells (hMSC) from bone marrow, 1 did not promote cell proliferation, but distinctly enhanced osteogenic differentiation of hMSC in time- and dose-dependent manners. In six human cancer cell lines, 1 showed a moderate inhibitory effect on cell proliferation, with IC50 values of 21.42-25.85 µmol·L(-1).

Griffipavixanthone from Garcinia oblongifolia champ induces cell apoptosis in human non-small-cell lung cancer H520 cells in vitro.

Griffipavixanthone (GPX) is a dimeric xanthone which was isolated in a systematic investigation of Garcinia oblongifolia Champ. In this study, we investigate the effect of GPX on cell proliferation and apoptosis on human Non-small-cell lung cancer (NSCLC) cells in vitro and determine the mechanisms of its action. GPX inhibited the growth of H520 cells in dose- and time-dependent manners, with IC50 values of 3.03 ± 0.21 µM at 48 h. The morphologic characteristics of apoptosis and apoptotic bodies were observed by fluorescence microscope and transmission electron microscope. In addition, Annexin V/PI double staining assay revealed that cells in early stage of apoptosis were significantly increased upon GPX treatment dose-dependently. Rh123 staining assay indicated that GPX reduced the mitochondrial membrane potential. DCFH-DA staining revealed that intracellular ROS increased with GPX treatment. Moreover, GPX cleaved and activated caspase-3. In summary, this study showed that GPX inhibited H520 cell proliferation in dose- and time-dependent manner. Further mechanistic study indicated that GPX induced cell apoptosis through mitochondrial apoptotic pathway accompanying with ROS production. Our results demonstrate the potential application of GPX as an anti-non-small cell lung cancer agent.

Three new anti-inflammatory stilbenoids and a diphenyl ether derivative from Cajanus cajan.

Three new stilbenoids, namely two rare plant-derived phenanthrenes denominated Cajananthrenes A and B (1, 2) and one bibenzyl named Cajanbenzyl (3), together with a diphenyl ether derivative designated Cajanether (4), as well as five other known compounds (5-9) were isolated from the ethanolic extract of the leaves of Cajanus cajan. Their structures were determined through extensive spectroscopic analysis including UV, IR, NMR (1D and 2D) and HRESIMS as well. A plausible biogenesis pathway was proposed for the biosynthesis of compounds 1-3. Compounds 1 and 2 displayed moderate anti-inflammatory activity as evident from the inhibitory effect on NO production in LPS-stimulated RAW 264.7 macrophages with IC50 values of 73.6 and 44.6 µM respectively.

Four new isocoumarins from Cajanus cajan.

Four novel new isocoumarins, cajanolactone B, C, D1 and D2 (1-4), were isolated from ethanolic extracts of the leaves of Cajanus cajan. The structural elucidation has been completed mainly depending on extensive spectroscopic analysis including UV, IR, NMR (1D and 2D), HRESIMS and chiral analysis. Notably, all these new isocoumarins were found to exist in racemic forms, among which compounds 3 and 4 share the same planar structure. This finding suggests that at least the biosynthesis of isocoumarin in C. cajan is chiral tolerant. A plausible biogenetic pathway of compounds 1-4 is proposed.

Xanthine oxidase inhibitory constituents from the roots of Ampelopsis japonica.

Bioassay-guided purification of the xanthine oxidase (XOD) inhibitory extract of the roots of Ampelopsis japonica resulted in the isolation of two new triterpenoids (1-2), designated Ampejaponoside A and B, along with sixteen known compounds (3-18). The structures of Ampejaposide A and B were elucidated by comprehensive analysis of spectroscopic data with the structures of the known compounds 3-18 confirmed by comparison the spectral data with corresponding values reported in literatures. All the isolates were evaluated for their XOD inhibitory activity in vitro. As a result, compounds 2, 8, and 14-16 displayed significant XOD inhibitory effect, particularly 16 being the most potent with an IC50 value of 0.21 µM, superior to positive substance allopurinol (IC50 1.95 µM). Molecular docking uncovered a unique interaction mode of 16 with the active site of XOD. The current study showed that the triterpenoids and polyphenols from A. japonica could serve as new lead compounds with the potential to speed up the development of novel XOD inhibitors with clinical potential to treat hyperuricaemia and gout.

Longistylin A from Cajanus cajan (L.) Millsp. disturbs glycerophospholipid metabolism and cytokinin biosynthesis of Nocardia seriolae.

ETHNOPHARMACOLOGICAL RELEVANCE: Nocardiosis is an uncommon infectious disease that bears certain similarities to tuberculosis, with a continuous increase in its incidence and a poor prognosis. In traditional Chinese medicine, the leaves of Cajanus cajan (L.) Millsp. are employed to treat wounds, malaria, coughs, and abdominal pain. AIM OF THE STUDY: In this study, we investigated the effects and mechanisms of longistylin A (LGA), a natural stilbene isolated from C. cajan, as a potential antibiotic against nocardiosis. MATERIALS AND METHODS: LGA was isolated from the leaves of C. cajan and assessed using a minimum bactericidal concentration (MBC) determination against Nocardia seriolae. Multi-omics analysis encompassing genes, proteins, and metabolites was conducted to investigate the impact of LGA treatment on N. seriolae. Additionally, quantitative analysis of 40 cytokinins in N. seriolae mycelium was performed to assess the specific effects of LGA treatment on cytokinin levels. Cryo-scanning electron microscopy was utilized to examine morphological changes induced by LGA treatment, particularly in the presence of exogenous trans-zeatin-O-glucoside (tZOG). The therapeutic effect of LGA was investigated by feeding N. seriolae-infected largemouth bass. RESULTS: LGA exhibited significant efficacy against N. seriolae, with MBC value of 2.56 µg/mL. Multi-omics analysis revealed that LGA disrupted glycerophospholipid metabolism and hormone biosynthesis by notably reducing the expression of glycerol-3-phosphate dehydrogenase and calmodulin-like protein. Treatment with LGA markedly disrupted 12 distinct cytokinins in N. seriolae mycelium. Additionally, the addition of exogenous tZOG counteracted the inhibitory effects of LGA on filamentous growth, resulting in mycelial elongation and branching. Furthermore, LGA treatment improved the survival rate of largemouth bass infected with N. seriolae. CONCLUSIONS: We found for the first time that LGA from C. cajan exhibited significant efficacy against N. seriolae by interfering with glycerophospholipid metabolism and cytokinin biosynthesis.

Pinostrobin from plants and propolis against human coronavirus HCoV-OC43 by modulating host AHR/CYP1A1 pathway and lipid metabolism.

Coronaviruses, as enveloped positive-strand RNA viruses, manipulate host lipid compositions to enable robust viral replication. Temporal modulation of the host lipid metabolism is a potential novel strategy against coronaviruses. Here, the dihydroxyflavone pinostrobin (PSB) was identified through bioassay that inhibited the increment of human coronavirus OC43 (HCoV-OC43) in human ileocecal colorectal adenocarcinoma cells. Lipid metabolomic studies showed that PSB interfered with linoleic acid and arachidonic acid metabolism pathways. PSB significantly decreased the level of 12, 13- epoxyoctadecenoic (12, 13-EpOME) and increased the level of prostaglandin E2. Interestingly, exogenous supplement of 12, 13-EpOME in HCoV-OC43-infected cells significantly stimulated HCoV-OC43 virus replication. Transcriptomic analyses showed that PSB is a negative modulator of aryl hydrocarbon receptor (AHR)/cytochrome P450 (CYP) 1A1signaling pathway and its antiviral effects can be counteracted by supplement of FICZ, a well-known AHR agonist. Integrative analyses of metabolomic and transcriptomic indicated that PSB could affect linoleic acid and arachidonic acid metabolism axis through AHR/CYP1A1 pathway. These results highlight the importance of the AHR/CYP1A1 pathway and lipid metabolism in the anti-coronavirus activity of the bioflavonoid PSB.

Inhibitory Mechanism of Pinosylvin Monomethyl Ether against Aspergillus flavus.

Control of Aspergillus flavus is beneficial for the agricultural economy and food safety. Stilbenes exhibit antifungal properties through an unknown mechanism. Here, six stilbenes isolated from Cajanus cajan were screened for anti-A. flavus activity. Among them, pinosylvin monomethyl ether (PME) showed the strongest anti-A. flavus activity and has a broad antifungal spectrum with negligible hemolysis within the concentration range measured. PME inhibited the spore germination of A. flavus and the accumulation of aflatoxin B1. Mechanistic studies showed that PME could bind the cell membrane phospholipids, resulting in increased permeability and decreased fluidity. Further metabolic analysis showed that PME caused the lysis of cell membranes and subsequent collapse of spores, which resulted in a cell wall autolysis-like phenotype. Structure-activity relationship analysis revealed the importance of maintaining amphiphilicity harmony by substituent groups for the antifungal activity of stilbenes. Together, natural stilbenes are promising antifungal lead compounds worthy of further exploration and research for potential application in the food, pharmaceutical, and agricultural industries.