[Two new benzoyl-sesquiterpenes from Mesona chinensis].

Mesona chinensis is a common medicinal and edible plant in the Lingnan region of China, which has extensive pharmacological activity. However, the study of its chemical constituents is not sufficient. In this study, a variety of modern chromatographic separation techniques were used to isolate two compounds from 95% ethanol extract of the grass parts of M. chinensis. Their absolute configurations were determined by ultraviolet spectroscopy(UV), infrared spectroscopy(IR), high resolution mass spectrometry(HR-ESI-MS), 1D and 2D nuclear magnetic resonance(1D NMR and 2D NMR), and single-crystal X-ray diffraction(SC-XRD). Specifically, they were two new benzoyl-sesquiterpenes and named mesonanol A and mesonanol B, respectively. The results of the pharmacological activity evaluation showed that neither of the two new compounds showed obvious antiviral and anti-inflammatory activities.

Secoiridoid glycosides from the fruits of Ligustrum lucidum and their in vitro anti-inflammatory activity.

Seven new secoiridoid glycosides (1-7), together with a known analogue (8), were isolated from the fruits of Ligustrum lucidum. Their structures with absolute configurations were determined by HR-ESI-MS, 1D and 2D NMR, and electronic circular dichroism (ECD) spectroscopic analysis, as well as biogenetic consideration. Compounds 1 and 2 are the first examples of secoiridoid glycoside dimers featuring a rare rearranged oleoside-type secoiridoid moiety, and compounds 3-7 represent a new class of oleoside-type secoiridoid glycosides with unusual stereochemistry at C-1 position. A plausible biosynthetic pathway for this group of unusual secoiridoid glycosides was also proposed herein. In addition, the isolates were evaluated for their in vitro anti-inflammatory activity, and all tested compounds exhibited modest inhibitory effects against nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.

Prinsepia utilis Royle leaf extract: Ameliorative effects on allergic inflammation and skin lesions in allergic contact dermatitis and polyphenolic profiling through UPLC-MS/MS coupled to chemometric analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Allergic contact dermatitis (ACD) is a common allergic inflammatory disease that is concomitant with skin swelling, redness, dry itching, and relapses. Prinsepia utilis Royle, a Chinese and Indian folk medicine, is rich in polyphenols with potential anti-inflammatory and skin-protective activities. However, the underlying mechanism of P. utilis leaf (PUL) in the treatment of ACD and its functional basis remains unclear. AIM OF THE STUDY: This study is aimed to explore and reveal the active substances and mechanism of PUL against ACD. MATERIALS AND METHODS: Hyaluronidase inhibitory assay and fluorescein isothiocyanate (FITC)-induced ACD mouse model were performed to assess the antiallergic effects of PUL in vitro and in vivo. Different solvents were applied to obtain multiple PUL extracts. The extracts were further tested for total phenolic content (TPC) and total flavonoid content (TFC) by using spectrophotometric assays. Polyphenolic profiles were analyzed by using ultrahigh-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-QTOF-MS/MS), and a simultaneous quantification method was established using UPLC-QTrap-MS/MS through multiple reaction monitoring (MRM) and applied to analyze the pharmacokinetics of the multiple major polyphenols of PUL in mice. RESULTS: The water extract of PUL with the highest TPC/TFC exhibited the strongest antihyaluronidase effect (IC50 = 231.93 µg/mL). In vivo assays indicated that the oral administration of PUL water extract dose-dependently attenuated ACD-like symptoms by decreased interleukin (IL)-4, IL-5, IL-13, IL-33, thymic stromal lymphopoietin, and IgE production, suppressed eosinophil and basophil secretion, and increasing the expression of tight junction (TJ) proteins (claudin-1 [CLDN-1] and occludin). Concomitantly, UPLC-QTOF-MS/MS analysis enabled the identification of 60 polyphenols and the pharmacokinetic parameters of seven quantified constituents of PUL were characterized. Four compounds, trans-p-coumaric acid 4-O-ß-D-glucopyranoside (11), vicenin-2 (21), isoschaftoside (31), and kaempferol 3-O-(2″,6″-di-O-α-L-rhamnopyransoyl)-ß-D-glucopyranoside (38) which displayed satisfactory pharmacokinetic features, were considered as potential effective substances in PUL. CONCLUSIONS: PUL water extract ameliorated the allergic inflammation of ACD by repairing the epithelial barrier and alleviating Th2-type allergic inflammation. The anti-allergic effect of PUL is closely related to its phenolic substances, and compounds 11, 21, 31, and 38 were the active substances of PUL. It revealed that P. utilis could be developed as a new source of antiallergic agents for ACD therapy.

Bixasteroid, a new compound from the fruits of Bixa orellana and its anti-inflammatory activity.

Bixasteroid (1), one new steroid together with five known compounds (2-6), were isolated from the ethyl acetate fraction of ethanol extract of Bixa orellana fruits. All of these known compounds were isolated from the plant for the first time. Their structures were elucidated on the basis of spectroscopic analysis, and the absolute configuration of compound 1 was determined by X-ray crystallographic data analysis as well as by the quantum chemical ECD calculations. All the isolated compounds were tested for their anti-inflammatory activities. Compounds 1 and 2 showed inhibiting NO release activities in LPS-induced RAW 264.7 macrophages with the IC50 values of 4.72 ± 0.28 and 5.48 ± 1.48 µM, respectively.

Identification of Photocatalytic Alkaloids from Coptidis Rhizome by an Offline HPLC/CC/SCD Approach.

Natural products continue to be a valuable source of active metabolites; however, researchers of natural products are mostly focused on the biological effects, and their chemical utility has been less explored. Furthermore, low throughput is a bottleneck for classical natural product research. In this work, a new offline HPLC/CC/SCD (high performance liquid chromatography followed by co-crystallization and single crystal diffraction) workflow was developed that greatly expedites the discovery of active compounds from crude natural product extracts. The photoactive total alkaloids of the herbal medicine Coptidis rhizome were firstly separated by HPLC, and the individual peaks were collected. A suitable coformer was screened by adding it to the individual peak solution and observing the precipitation, which was then redissolved and used for co-crystallization. Seven new co-crystals were obtained, and all the single crystals were subjected to X-ray diffraction analysis. The molecular structures of seven alkaloids from milligrams of crude extract were resolved within three days. NDS greatly decreases the required crystallization amounts of alkaloids to the nanoscale and enables rapid stoichiometric inclusion of all the major alkaloids with full occupancy, typically without disorder, affording well-refined structures. It is noteworthy that anomalous scattering by the coformer sulfur atoms enables reliable assignment of absolute configuration of stereogenic centers. Moreover, the identified alkaloids were firstly found to be photocatalysts for the green synthesis of benzimidazoles. This study demonstrates a new and green phytochemical workflow that can greatly accelerate natural product discovery from complex samples.

Chemical Characterization and Atherosclerosis Alleviation Effects of Gypenosides from Gynostemma pentaphyllum through Ameliorating Endothelial Dysfunction via the PCSK9/LOX-1 Pathway.

Dietary saponins have the potential to ameliorate atherosclerosis (AS). Gypenosides of Gynostemma pentaphyllum (GPs) have been used as functional foods to exhibit antiatherosclerotic activity. The present study aimed to explore the protective effect, underlying mechanism and active substances of GPs on AS in vivo and in vitro. Results demonstrated GPs administration reduced the serum concentrations of TC and LDL-C, upregulated the plasma HDL-C content, inhibited the secretion of ICAM-1, VCAM-1, and MCP-1, and alleviated vascular lesions in VitD3 plus high cholesterol diet-induced AS rats as well as reduced adhesion factors levels in ox-LDL-stimulated HUVECs, which was potentially associated with suppressing PCSK9/LOX-1 pathway. Further activity-guided phytochemical investigation of GPs led to the identification of five new dammarane-type glycosides (1-5) and ten known analogs (6-15). Bioassay evaluation showed compounds 1, 6, 7, 12, 13, and 14 observably reduced the expressions of PCSK9 and LOX-1, as well as the secretion of adhesion factors in injured HUVECs. Molecular docking experiments suggested that the active saponins of GPs might bind to the allosteric pocket of PCSK9 located at the catalytic and C-terminal domains, and 2α-OH-protopanaxadiol-type gypenosides might exert a higher affinity for an allosteric binding site on PCSK9 by hydrogen-bond interaction with ARG-458. These findings provide new insights into the potential nutraceutical application of GPs and their bioactive compounds in the prevention and discovery of novel therapeutic strategies for AS.

Citri Reticulatae Pericarpium (Chenpi): A multi-efficacy pericarp in treating cardiovascular diseases.

Citri Reticulatae Pericarpium (CRP) has been utilized as a versatile medicinal herb with wide cardiovascular benefits in Asian nations for centuries. Accumulating evidence suggests that CRP and its components are effective in preventing cardiovascular diseases (CVDs) such as atherosclerosis, myocardial infarction, myocardial ischemia, arrhythmia, cardiac hypertrophy, heart failure, and hypertension. Studies show that the two most bioactive components of CRP are flavonoids and volatile oils. The cardiovascular protective effects of CRP have attracted considerable research interest due to its hypolipidemic, antiplatelet activity, antioxidant and anti-inflammatory effects. Hereby, we provide a rigorous and up-to-date overview of the cardiovascular protective properties and the potential molecular targets of CRP, and finally highlight the pharmacokinetics and the therapeutic potential of the main pharmacologically active components of CRP to treat CVDs.

New insights into antiangiogenic therapy resistance in cancer: Mechanisms and therapeutic aspects.

Angiogenesis is a hallmark of cancer and is required for tumor growth and progression. Antiangiogenic therapy has been revolutionarily developing and was approved for the treatment of various types of cancer for nearly two decades, among which bevacizumab and sorafenib continue to be the two most frequently used antiangiogenic drugs. Although antiangiogenic therapy has brought substantial survival benefits to many cancer patients, resistance to antiangiogenic drugs frequently occurs during clinical treatment, leading to poor outcomes and treatment failure. Cumulative evidence has demonstrated that the intricate interplay among tumor cells, bone marrow-derived cells, and local stromal cells critically allows for tumor escape from antiangiogenic therapy. Currently, drug resistance has become the main challenge that hinders the therapeutic efficacies of antiangiogenic therapy. In this review, we describe and summarize the cellular and molecular mechanisms conferring tumor drug resistance to antiangiogenic therapy, which was predominantly associated with redundancy in angiogenic signaling molecules (e.g., VEGFs, GM-CSF, G-CSF, and IL17), alterations in biological processes of tumor cells (e.g., tumor invasiveness and metastasis, stemness, autophagy, metabolic reprogramming, vessel co-option, and vasculogenic mimicry), increased recruitment of bone marrow-derived cells (e.g., myeloid-derived suppressive cells, tumor-associated macrophages, and tumor-associated neutrophils), and changes in the biological functions and features of local stromal cells (e.g., pericytes, cancer-associated fibroblasts, and endothelial cells). We also review potential biomarkers to predict the response to antiangiogenic therapy in cancer patients, which mainly consist of imaging biomarkers, cellular and extracellular proteins, a certain type of bone marrow-derived cells, local stromal cell content (e.g., pericyte coverage) as well as serum or plasma biomarkers (e.g., non-coding RNAs). Finally, we highlight the recent advances in combination strategies with the aim of enhancing the response to antiangiogenic therapy in cancer patients and mouse models. This review introduces a comprehensive understanding of the mechanisms and biomarkers associated with the evasion of antiangiogenic therapy in cancer, providing an outlook for developing more effective approaches to promote the therapeutic efficacy of antiangiogenic therapy.

Stilbenes from the leaves of Cajanus cajan and their in vitro anti-inflammatory activities.

Eighteen stilbenes (1-18), including six previously undescribed ones (1-6), with diverse modification patterns were isolated from the leaves of edible and medicinal plant Cajanus cajan. Among the new isolates, compounds 1-3 were initially obtained as three racemic mixtures, which were further resolved into three pairs of optically pure enantiomers, respectively, by chiral HPLC. Besides, compounds 8, 10, 11, and 18 were obtained from C. cajan for the first time. The chemical structures and absolute configurations of the new stilbenes were elucidated unambiguously on the basis of extensive spectroscopic analyses, single crystal X-ray crystallographic study, and quantum chemical electronic circular dichroism (ECD) calculations. In addition, the in vitro anti-inflammatory activities of all isolated stilbenes were evaluated. Compounds 2, 9, 10, 11, and 14 exerted moderate suppression of nitric oxide (NO) secretion in lipopolysaccharide (LPS)-induced RAW264.7 cells without exhibiting substantial cytotoxicity.

Anti-inflammatory, anti-angiogenetic and antiviral activities of dammarane-type triterpenoid saponins from the roots of Panax notoginseng.

Panax notoginseng has been used both as a traditional medicine and as a functional food for hundreds of years in Asia. However, the active constituents from P. notoginseng and their pharmacologic properties still need to be further explored. In this study, one new dammarane-type triterpenoid saponin (1), along with fourteen known analogs (2-15) were isolated and identified from the roots of P. notoginseng. The anti-inflammatory, anti-angiogenetic and anti-dengue virus effects of these isolated compounds were further evaluated. Compounds 1, 3, 5-7 and 10-12 exerted anti-inflammatory effects in two different zebrafish inflammatory models. Among them, 11, with the most significant activities, alleviated the inflammatory response by blocking the MyD88/NF-κB and STAT3 pathways. Moreover, compound 15 showed anti-angiogenetic activities in Tg(fli1:EGFP) and Tg(flk1:GFP) zebrafish, while 3 and 5 only inhibited angiogenesis in Tg(fli1:EGFP) zebrafish. Additionally, compounds 1, 3, 6, 8, 9 and 12 suppressed the replication of dengue virus either at the viral adsorption and entry stages or at the intracellular replication step. In conclusion, these findings enrich knowledge of the diversity of saponins in P. notoginseng and suggest that the dammarane-type triterpenoid saponins from P. notoginseng may be developed as potential functional foods to treat inflammation, angiogenesis or dengue-related diseases.

Angiogenesis-Inhibitory Piperidine Alkaloids from the Leaves of Microcos paniculata.

Eight new 2,6-disubstituted piperidin-3-ol alkaloids (1-8), featuring a C10 unsaturated alkyl side chain, together with three previously reported analogues (9-11) were isolated from the leaves of medicinal plant Microcos paniculata. Their structures and absolute configurations were elucidated unambiguously by means of 1D and 2D NMR spectroscopic data analysis, modified Mosher's method, Snatzke's method, and quantum chemical electronic circular dichroism (ECD) calculations, as well as single-crystal X-ray crystallography. The isolates were evaluated for their antiangiogenic effects on human umbilical vein endothelial cells (HUVECs). Compound 2 displayed an inhibitory effect on tube formation of HUVECs in a concentration-dependent manner.

Total Saponins of Panax notoginseng Activate Akt/mTOR Pathway and Exhibit Neuroprotection in vitro and in vivo against Ischemic Damage.

OBJECTIVE: To reveal the neuroprotective effect and the underlying mechanisms of a mixture of the main components of Panax notoginseng saponins (TSPN) on cerebral ischemia-reperfusion injury and oxygen-glucose deprivation/reoxygenation (OGD/R) of cultured cortical neurons. METHODS: The neuroprotective effect of TSPN was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, flow cytometry and live/dead cell assays. The morphology of dendrites was detected by immunofluorescence. Middle cerebral artery occlusion (MCAO) was developed in rats as a model of cerebral ischemia-reperfusion. The neuroprotective effect of TSPN was evaluated by neurological scoring, tail suspension test, 2,3,5-triphenyltetrazolium chloride (TTC) and Nissl stainings. Western blot analysis, immunohistochemistry and immunofluorescence were used to measure the changes in the Akt/mammalian target of rapamycin (mTOR) signaling pathway. RESULTS: MTT showed that TSPN (50, 25 and 12.5 µ g/mL) protected cortical neurons after OGD/R treatment (P<0.01 or P<0.05). Flow cytometry and live/dead cell assays indicated that 25 µ g/mL TSPN decreased neuronal apoptosis (P<0.05), and immunofluorescence showed that 25 µ g/mL TSPN restored the dendritic morphology of damaged neurons (P<0.05). Moreover, 12.5 µ g/mL TSPN downregulated the expression of Beclin-1, Cleaved-caspase 3 and LC3B-II/LC3B-I, and upregulated the levels of phosphorylated (p)-Akt and p-mTOR (P<0.01 or P<0.05). In the MCAO model, 50 µ g/mL TSPN improved defective neurological behavior and reduced infarct volume (P<0.05). Moreover, the expression of Beclin-1 and LC3B in cerebral ischemic penumbra was downregulated after 50 µ g/mL TSPN treatment, whereas the p-mTOR level was upregulated (P<0.05 or P<0.01). CONCLUSION: TSPN promoted neuronal survival and protected dendrite integrity after OGD/R and had a potential therapeutic effect by alleviating neurological deficits and reversing neuronal loss. TSPN promoted p-mTOR and inhibited Beclin-1 to alleviate ischemic damage, which may be the mechanism that underlies the neuroprotective activity of TSPN.

Proanthocyanidin A1 promotes the production of platelets to ameliorate chemotherapy-induced thrombocytopenia through activating JAK2/STAT3 pathway.

BACKGROUND: Chemotherapy-induced thrombocytopenia (CIT) is a severe adverse drug reaction, and the main reason for CIT is the destruction of megakaryocytes (MKs, precursor cells of platelet) in bone marrow by chemotherapy. Peanut skin, the seed coat of Arachis hypogaea L., is a traditional Chinese medicine commonly used to treat thrombocytopenia. However, its active compounds and the mechanisms remain unclear. PURPOSE: This study aims to clarify the active compounds of peanut skin to exhibit thrombogenic effects against CIT and their underlying mechanisms in vitro and in vivo. STUDY DESIGN: The bioassay-guided isolation based on the proliferation of MKs was used to explore the possible platelet-enhancing ingredients in peanut skin. HSCCC technique coupled with preparative HPLC was used to separate the active compounds. Dami cells and carboplatin-treated mice model were used to evaluate the thrombogenic effects of PS-1. Network pharmacology, molecular docking, dynamics simulation studies, kinase activity, surface plasmon resonance (SPR), cellular thermal shift assay (CETSA), isothermal dose-response fingerprint (ITDRFCETSA) and western blot analysis were performed to investigate the mechanisms of PS-1. RESULTS: Proanthocyanidin A1 (PS-1) and its stereoisomers (PS-2-4) were demonstrated to promote the proliferation of MKs (Dami cells), especially PS-1 (EC50 = 8.58 µM). Further studies demonstrated that PS-1 could induce the differentiation of Dami cells in dose/time-dependent manner. Biological target analysis showed that PS-1 directly bound to JAK2 (KD = 2.06 µM) to exert potent activating effect (EC50 = 0.66 µM). Oral administration of PS-1 (25 or 50 mg/kg) significantly improved CIT, but this effect was confirmed to be inhibited by JAK2 inhibitor AG490, indicating that PS-1 exerted its efficacy through JAK2 in vivo. CONCLUSION: Proanthocyanins (PS-1-4) derived from peanut skin were first clarified as platelet-enhancing ingredients to improve CIT. The underlying mechanism of PS-1 was proved to promote the proliferation and differentiation of MKs via JAK2/STAT3 pathway both in vitro and in vivo.

Screening of Bufadienolides from Toad Venom Identifies Gammabufotalin as a Potential Anti-inflammatory Agent.

Toad venom (Chansu) is used in the treatment of infectious and inflammatory diseases in China and East/Southeast Asian countries. However, the anti-inflammatory components of toad venom have not yet been systematically evaluated and clearly defined. To investigate the anti-inflammatory effects of toad venom and identify new anti-inflammatory ingredients, we used zebrafish, an alternative drug screening model, to evaluate the anti-inflammatory effects of 14 bufadienolides previously isolated from toad venom. Most of the bufadienolides were found to exert significant anti-inflammatory effects on lipopolysaccharide-, CuSO4-, or tail transection-induced zebrafish inflammatory models. Moreover, gammabufotalin ( 6: ) inhibits lipopolysaccharide-induced inflammation by suppressing the myeloid differentiation primary response 88/nuclear factor-kappa B and STAT3 signal pathways. This study confirms the potential of zebrafish in drug screening, clarifies the anti-inflammatory effects of bufadienolides from toad venom, and indicates that gammabufotalin may be developed as a novel therapeutic agent for inflammatory diseases in the future.

Discovery of Eucalyptin C, derived from the fruits of Eucalyptus globulus Labill., as a novel selective PI3Kγ inhibitor for immunosuppressive treatment.

The fruits of Eucalyptus globulus Labill. are known to have a plenty of medicinal properties, such as anti-tumor, anti-inflammatory, and immunosuppressive activity. Our previous study found that the phloroglucinol-sesquiterpene adducts in the fruits of E. globulus were immunosuppressive active constituents, especially Eucalyptin C (EuC). Phosphoinositide 3-kinases-γ (PI3Kγ) plays a pivotal role in T cell mediated excessive immune responses. In this study, EuC was first discovered to be a novel selective PI3Kγ inhibitor with an IC50 value of 0.9 µmol·L-1 and selectivity over 40-fold towards the other PI3K isoforms. Molecular docking, molecular dynamics simulation, and cellular thermal shift assay showed that EuC bound to PI3Kγ. Furthermore, EuC suppressed the downstream of PI3Kγ to induce the apoptosis and inhibit the activation of primary spleen cells derived from allergic contact dermatitis mice. This work highlights the role of the fruits of E. globulus as a source of bioactive plant with immunosuppressive activity.

Quassinoids from the Roots of Eurycoma longifolia and Their Anti-Proliferation Activities.

A phytochemical investigation on the roots of medicinal plant Eurycoma longifolia resulted in the isolation of 10 new highly oxygenated C20 quassinoids longifolactones G‒P (1-10), along with four known ones (11-14). Their chemical structures and absolute configurations were unambiguously elucidated on the basis of comprehensive spectroscopic analysis and X-ray crystallographic data. Notably, compound 1 is a rare pentacyclic C20 quassinoid featuring a densely functionalized 2,5-dioxatricyclo[5.2.2.04,8]undecane core. Compound 4 represents the first example of quassinoids containing a 14,15-epoxy functionality, and 7 features an unusual α-oriented hydroxyl group at C-14. All isolated compounds were evaluated for their anti-proliferation activities on human leukemia cells. Among the isolates, compounds 5, 12, 13, and 14 potently inhibited the in vitro proliferation of K562 and HL-60 cells with IC50 values ranging from 2.90 to 8.20 µM.

[Triterpenoids from leaves of Ilex guayusa].

The chemical constituents from the leaves of Ilex guayusa were investigated. Sixteen triterpenoids were isolated from the 95% ethanol extract of dried leaves of I. guayusa by silica gel, Sephadex LH-20, and ODS column chromatographies and semi-prepa-rative HPLC. Those triterpenoids were identified by NMR, HR-MS, and literature analysis: 3ß-hydroxy-11α,12α-epoxy-24-nor-urs-4(23)-ene-28,13ß-olide(1), 3ß-hydroxy-24-nor-4(23),12-oleanadien-28-methyl ester(2), oleanolic acid(3), 3ß,28-dihydroxy-12-oleanene(4), 2α,3ß-dihydroxy-11α,12α-epoxy-24-'nor-olean-4(23)-ene-28,13ß-olide(5), ursolic acid(6), 3ß,23-dihydroxy ursolic acid(7), 3ß,28-dihydroxy-12-ursene(8), 3ß-28-nor-urs-12-ene-3,17-diol(9), 3ß-hydroxyurs-11-ene-28,13ß-olide(10), 13ß,28-epoxy-3ß-hydroxy-11-ursene(11), 3ß-hydroxy-28,28-dimethoxy-12-ursene(12), 3ß-hydroxy-24-nor-urs-4(23),12-dien-28-oic acid(13), 3ß-hydroxy-24-nor-urs-4(23),12-dien-28-methyl ester(14), 2α,3ß-dihydroxy-11α,12α-epoxy-24-nor-urs-4(23)-ene-28,13ß-olide(15) and 2α,3ß-dihydroxy-11α,12α-epoxy-24-nor-urs-4(23),20(30)-dien-28,13ß-olide(16). Compounds 1-2 were new compounds, and compounds 4-5, 7 and 9-16 were isolated from I. guayusa for the first time.

3'-Oxo-tabernaelegantine A (OTNA) selectively relaxes pulmonary arteries by inhibiting AhR.

BACKGROUND: Pulmonary arterial hypertension (PAH), characterized by pulmonary artery constriction and vascular remodeling, has a high mortality rate. New drugs for the treatment of PAH urgently need to be developed. PURPOSE: This study was designed to investigate the vasorelaxant activity of OTNA in isolated pulmonary arteries, and explore its molecular mechanism. METHODS: Pulmonary arteries and thoracic aortas were isolated from mice, and vascular tone was tested with a Wire Myograph System. Nitric oxide levels were determined with DAF-FM DA and DAX-J2™ Red. Cellular thermal shift assays, microscale thermophoresis, and molecular docking were used to identify the interaction between OTNA and aryl hydrocarbon receptor (AhR). The levels of PI3K, p-PI3K, Akt, p-Akt, eNOS, p-eNOS, and AhR were analyzed by Western blotting. RESULTS: OTNA selectively relaxed the isolated pulmonary artery rings in an endothelium-dependent manner. Mechanistic study showed that OTNA induced NO production through activation of the PI3K/Akt/eNOS pathway in endothelial cells. Furthermore, we also found that OTNA directly bound to AhR and activated the PI3K/Akt/eNOS pathway to dilate pulmonary arteries by inhibiting AhR. CONCLUSIONS: OTNA relaxes pulmonary arteries by antagonizing AhR. This study provides a new natural antagonist of AhR as a promising lead compound for PAH treatment.

[Two new pyranonaphthoquinones from Mansoa alliacea].

Mansoa alliacea,commonly known as garlic vine,is native to the tropical rain forests of South America and widely cultivated in South China. As a popular folk medicine with various biological activities,however,this plant remains to be fully elucidated in terms of its phytochemical constituents. In this study,two new pyranonaphthoquinones were isolated from the 95% ethanol extract of the leaves and twigs of M. alliacea by various chromatographic approaches including silica gel,octadecyl silica( ODS),Sephadex LH-20,and preparative high-performance liquid chromatography( PHPLC). Their structures were determined to be 8,9-dimethoxy-α-lapachone( 1) and 7-hydroxy-8,9-dimethoxy-α-lapachone( 2) by comprehensive spectroscopic analyses and therefore respectively named as mansonin A( 1) and mansonin B( 2).

Phloroglucinol-derived lipids from the leaves of Syzygium cumini and their neuroprotective activities.

Based on the typical HPLC-UV-MS profiles and characteristic 1H NMR signals, twelve new phloroglucinol-derived lipids (1-12), featuring a long linear aliphatic side chain, together with three known ones (13-15) were isolated from the ethanol extract of the leaves of Syzygium cumini. Their structures were elucidated on the basis of extensive NMR spectroscopic analyses and mass spectrometric data. Compounds 1-5 characterize an enolizable ß,ß'-tricarbonyl motif with a cyclohexa-3,5-dien-1-one core that is hitherto undescribed in phloroglucinol-derived lipids. Compounds 4 and 10-12 are novel phloroglucinol-derived lipids containing an uncommon methylene interrupted trans double bond in their polyunsaturated aliphatic side chains. A polyketide biogenetic pathway for those phloroglucinol-derived lipids was also proposed. In addition, the isolates were evaluated for their neuroprotective activities against oxygen-glucose deprivation and re­oxygenation (OGD/R)-induced Neuro-2a cell injury. Notably, compounds 1, 5, and 10-12 significantly improved viability of Neuro-2a cells after OGD/R damage.