Sesquiterpene lactones from Tithonia diversifolia with ferroptosis-inducing activities.

Eight previously undescribed sesquiterpene lactones (1-8), together with six known ones (9-14) were isolated from the aerial parts of Tithonia diversifolia (Hemsl.) A. Gray. The absolute configurations of these compounds were elucidated using HRMS, NMR spectroscopy, optical rotation measurements, X-ray crystallography, and ECD. Among them, sesquiterpene lactones 2-4 share a unique carbon skeleton with a rare C-3/C-4 ring-opened structure. Compounds 1 and 8 showed moderate inhibitory effects toward CT26 murine colon carcinoma cells by promoting lipid ROS production, highlighting their potential as ferroptosis inducers.

3-Hydroxyneocryptolepine, a new indoloquinoline alkaloid from the roots of Cryptolepis sanguinolenta (Lindl.) Schltr.

Phytochemical investigations of the African ethnomedicinal plant Cryptolepis sanguinolenta (Lindl.) Schltr. (Apocynaceae) have yielded only a small number of rare naturally occurring indoloquinoline alkaloids. Our recent work has resulted in the isolation of a new indoloquinoline named 3-hydroxyneocryptolepine, which was obtained from an ethanolic extract of the roots. The structure of the compound was elucidated based on 1D and 2D NMR as well as HRESIMS spectral evidence. LDL uptake promotion activity of the compound in HepG2 cells was not significant.

Eighteen iridoids from the roots and rhizomes of Valeriana jatamansi and their protective effects against α-hemolysin.

Thirteen previously undescribed iridoids (1-13), together with five known iridoids (14-18) were isolated from the roots and rhizomes of Valeriana jatamansi Jones. Their structures with absolute configurations were elucidated by analysis of MS, NMR, optical rotation and their experimental and calculated electronic circular dichroism spectra. All of the isolated compounds were tested for their protective effects against α-hemolysin-induced cell death in A549 cells. Compounds 14, 16 and 17 showed moderate protective effects, and compounds 15 and 18 showed weak protective effects.

Five undescribed abietane-type diterpenes of Callicarpa macrophylla.

A phytochemical investigation of the medicinal plant Callicarpa macrophylla resulted in the characterization of two rare rearrangement abietane-type diterpenoids, macrophypene F-G (1-2), and three abietane diterpenoids, named macrophypene H-J (3-5). Additionally, five known diterpenoids (6-10) were identified. The structures of the newly discovered compounds were fully established through extensive analysis of HRESIMS, 1D and 2D NMR data. The absolute configurations of the isolated compounds were determined using CD comparison, chemical methods, and X-ray crystal diffraction experiments. Subsequently, all isolated diterpenoids were evaluated for their inhibitory effects on extracellular PCSK9 protein levels by PCSK9 AlphaLISA screening. Jiadfenoic acid B (6, 56.80% inhibition at 20 µM) and holophyllin F (10, 43.18% inhibition at 20 µM) significantly decreased PCSK9 protein levels in medium of HepG2 cells.

Novel indoloquinoline alkaloid glycosides from Cryptolepis sanguinolenta (Lindl.) Schltr.

To explore the phytochemistry of the African ethnomedicinal plant Cryptolepis sanguinolenta (Lindl.) Schltr. (Apocynaceae) for rare indoloquinoline alkaloids, two novel indoloquinoline alkaloid glycosides, namely Cryptospirosanguine A (1) and B (2), were isolated from an ethanolic extract of the root. Their structures were elucidated based on spectral evidence. Furthermore, two known terpenoids were isolated from this plant for the first time.

Five undescribed guanidine alkaloids from Plumbago zeylanica.

Five undescribed guanidine alkaloids, plumbagines HK (1-4) and plumbagoside E (5), as well as five known analogues (6-10) were isolated from the roots of Plumbago zeylanica. Their structures were established by extensive spectroscopic analyses and chemical methods. In addition, 1-10 were accessed their anti-inflammatory activities by measuring nitric oxide (NO) concentrations in LPS-induced RAW 264.7 cells. However, all compounds especially 1 and 3-5 could not inhibit the secretion of NO but significant increase the secretion of NO. The result reminded us that 1-10 may become potential novel immune potentiators.

Five glycosylated phenolic derivatives from the bark of Ilex rotunda Thunb. and their anti-inflammatory activities.

Five new glycosylated phenolic derivatives, rotundosides A-E (1-5), and three known glycosides (6-8) were isolated from the 95% alcohol extract of the bark of Ilex rotunda. Their structures were elucidated by extensive spectroscopic analysis and comparison with the literature data. All new compounds possessed a [5-O-(E)-caffeoyl]-ß-D-apiofuranosyl-(1→6)-ß-D-glucopyranosyl group. The anti-inflammatory properties of all isolated compounds were evaluated using a modified nitric oxide (NO) production in lipopolysaccharide (LPS)-induced leukemia cells in mouse macrophage (RAW264.7) method. Compound 8, dracunculifoside H, showed significant anti-inflammatory activity in vitro.

Calysepins I-VII, Hexasaccharide Resin Glycosides from Calystegia sepium and Their Cytotoxic Evaluation.

Seven new hexasaccharide resin glycosides, named calysepins I-VII (1-7), with 27-membered rings, were obtained from the aerial parts of Calystegia sepium. Their structures with absolute configuration were established on the basis of spectroscopic data interpretation analysis and the use of chemical methods. They were defined as hexasaccharides composed of one d-quinovose, four d-glucose, and one l-rhamnose unit, and their sugar moieties were partially acylated by (2S)-methylbutanoic acid in 1-7 and (2R,3R)-nilic acid in 1-5 and 7, which mainly differed at the positions of acylation. Additionally, calysepin IV (4) exhibited cytotoxicity against A549 cells with an IC50 value of 5.2 µM.

Anti-inflammatory sesquiterpene dimers and diterpenes from the aerial part of Inula japonica.

Phytochemical investigation on the 95% alcohol extract of the aerial part of Inula japonica led to the isolation of three new compounds, inulanolides F-G (1-2) and 17α-carboxaldehyde-ent-kaur-18-oic acid (3), together with four known compounds (4-7). The structures of new compounds were elucidated by using spectroscopic data. Most of the isolated compounds showed significant anti-inflammatory activities.

Disease-resistant identification and analysis to transcriptome differences of blueberry leaf spot induced by beta-aminobutyric acid.

Leaf spot (Pestalotiopsis microspora) is one of the major fungal diseases in blueberry (Vaccinium corymbosum L.) production and if not treated promptly that can eventually lead to plant death. To prevent and control leaf spot effectively, we selected BABA (beta-aminobutyric acid) as an inducer, "Canlan" in blueberries of rabbit eyes varieties as experimental material and then induced and inoculated leaf spot on blueberries as an experimental group and used uninduced blueberries inoculated with leaf spot as the control group. A transcriptome sequencing library was built, allowing identification of disease resistance and transcriptome analysis. The results showed that the resistance of blueberry to leaf spot was significantly increased after induction by BABA, which can increase the activity of the enzymes PPO, POD, PAL and and ß-1,3-glucanase in blueberry leaves, inducing disease resistance of blueberries to leaf spot. Transcriptome sequencing results showed that there are 3953 genes participating in the processing of disease in KEGG metabolic pathways. Among the transcripts annotated to diseases, 1115 were involved in plant-pathogen interactions and 35 were involved in anthocyanin synthesis. Differential expression results showed that there were 900 upregulated differential genes and 531 downregulated differential genes, there were 70 genes highly expressed in the library. The results of Blast2PHI database revealed that among the genes related to leaf spot disease in blueberry, there were 727 transcription factors, 200 involved in disease prevention, 45 associated with cell circulation, effector proteins and 7 pathogenic genes controlling the biosynthesis of a-(1,3)-glucan.

Neolinulicin A and B from Inula japonica and their anti-inflammatory activities.

A phytochemical study performed on Inula japonica led to isolation of a new 1,10-seco-sesquiterpene dimer Neolinulicin A (1) and 1,10-seco-sesquiterpene Neolinulicin B (2), together with nine known sesquiterpenes (3-11). Among them, Neolinulicin A (1), which has a new carbon skeleton, was a Diels-Alder [4 + 2] adduct of two sesquiterpene moieties. Their structures were established by extensive spectroscopic analysis. All of the isolated compounds showed inhibition of NO production in RAW 264.7 macrophages. The findings might supply information for the future design of anti-inflammatory agents from I. japonica.

Teratopyrones A-C, Dimeric Naphtho-γ-Pyrones and Other Metabolites from Teratosphaeria sp. AK1128, a Fungal Endophyte of Equisetum arvense.

Bioassay-guided fractionation of a cytotoxic extract derived from a solid potato dextrose agar (PDA) culture of Teratosphaeria sp. AK1128, a fungal endophyte of Equisetum arvense, afforded three new naphtho-γ-pyrone dimers, teratopyrones A-C (1-3), together with five known naphtho-γ-pyrones, aurasperone B (4), aurasperone C (5), aurasperone F (6), nigerasperone A (7), and fonsecin B (8), and two known diketopiperazines, asperazine (9) and isorugulosuvine (10). The structures of 1-3 were determined on the basis of their spectroscopic data. Cytotoxicity assay revealed that nigerasperone A (7) was moderately active against the cancer cell lines PC-3M (human metastatic prostate cancer), NCI-H460 (human non-small cell lung cancer), SF-268 (human CNS glioma), and MCF-7 (human breast cancer), with IC50s ranging from 2.37 to 4.12 µM while other metabolites exhibited no cytotoxic activity up to a concentration of 5.0 µM.

Three new dibenzofurans from Cydonia oblonga Mill.

Phytochemical investigation of Cydonia oblonga Mill. collected in Xinjiang province, China, led to the isolation and identification of three new dibenzofurans (1-3) along with one known compound (4). Their structures were elucidated based on HRESIMS, spectroscopic data (IR, UV, 1D, 2D NMR) and X-ray diffraction analysis.

New flavonoid glycosides from seeds of Baccharoides anthelmintica.

Baccharoides anthelmintica is the most popular traditional Uighur medicines used for vitiligo. The chemical investigation of the seeds of B. anthelmintica led to the isolation of three new flavonoid glycosides (Vernosides A-C). Their structures were determined by comprehensive analysis of spectroscopic data including 1D and 2D NMR and HRMS data. Vernosides A-C were evaluated for their effects on tyrosinase activity, Vernoside B can enhance tyrosinase activity.

23,24-Dihydrocucurbitacin B promotes lipid clearance by dual transcriptional regulation of LDLR and PCSK9.

23,24-Dihydrocucurbitacin B (designated as C95 in this article) is a cucurbitane triterpenoid that has been shown to possess a variety of pharmacological activities, such as anti-inflammatory and anti-HIV-1 activities etc. In this study, we investigated the effects of 23,24-dihydrocucurbitacin B on lipid regulation. We showed that 23,24-dihydrocucurbitacin B (1-5 µM) dose-dependently promoted DiI-LDL uptake in HepG2 cells by upregulating low-density lipoprotein receptor (LDLR) protein. In HepG2 cells, 23,24-dihydrocucurbitacin B (1-10 µM) dose-dependently enhanced LDLR promoter activity by elevating the mature form of SREBP2 (sterol regulatory element binding protein 2) protein levels on one hand, and inhibited PCSK9 (proprotein convertase subtilisin/kexin type 9) promoter activity by attenuating HNF1α (hepatocyte nuclear factor-1α) protein levels in nuclei on the other hand. Consequently, the expression of LDLR protein markedly increased, whereas the PCSK9-mediated LDLR protein degradation decreased. In a high-cholesterol LVG golden Syrian Hamster model, administration of 23,24-dihydrocucurbitacin B (30 mg · kg-1⋅ d-1, intragastric, for 3 weeks) significantly decreased the serum LDL-cholesterol (LDL-C) levels. PCSK9 protein levels in the serum and liver tissues were significantly decreased, whereas LDLR protein levels in liver tissues were significantly increased in the treated animals as compared with the control animals. In conclusion, our study demonstrates for the first time that 23,24-dihydrocucurbitacin B exhibits dual transcriptional regulation of LDLR and PCSK9 in HepG2 cells by increasing SREBP2 protein levels and decreasing HNF1α protein levels in the nuclei. These results propose a new strategy to simultaneously manage LDLR and PCSK9 protein expression and provide a promising lead compound for drug development.

Magnesium lithospermate B ameliorates microcirculation perfusion in rats by promoting vascular NO production via activating the PI3K/AKT pathway.

Microcirculation morphologically refers to the blood flow in vessels of less than 150 µm in diameter, including arterioles, capillaries and venules, which provides nutrients and removes metabolic byproducts within tissues. Microcirculation dysfunction is involved in the pathological progress of many diseases, such as obesity, hypertension, and insulin resistance. In this study we investigated the effects of magnesium lithospermate B (MLB), an active compound of the traditional Chinese medicine Slavia miltiorrhiza, on the microcirculation dysfunction in rats and the underlying molecular mechanisms. The effects of MLB on microcirculation were assessed in vivo by measuring the hindlimb blood perfusion in dextran-induced microcirculation dysfunction rats and mesentery blood flow in anesthetized rats. We demonstrated that administration of MLB restored the impaired rat hindlimb blood flow and promoted the mesenteric micoperfusion in vivo. We further revealed in these two animal models that MLB treatment significantly increased the production of total nitrite in vascular tissues (mesentery, aorta, and heart), which was confirmed in human microvascular endothelial cells (HMEC-1) treated with MLB in vitro. Moreover, we showed that MLB treatment significantly increased the phosphorylation of endothelium nitric oxide synthase (eNOS) via inducing AKT phosphorylation in vivo and in vitro. Co-administration of the eNOS inhibitor L-NAME (20 mg/kg) abolished the protective effects of MLB against dextran-induced microcirculation dysfunction in rats, whereas pretreatment with PI3K inhibitor LY294002 (10 µM) prevented eNOS activation in MLB-treated HMEC-1 cells. Our results suggest that MLB can restore the microcirculation dysfunction via activating eNOS, and in turn enhancing the vascular nitric oxide production, which is medicated by MLB-caused activation of the PI3K/AKT pathway.

Indole alkaloid from Nauclea latifolia promotes LDL uptake in HepG2 cells by inhibiting PCSK9.

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been found to play a major role in atherosclerotic cardiovascular disease (ASCVD) by promoting hyperlipidemia. Its inhibition has therefore emerged as a viable drug target for improving the outcome of ASCVD. However, current monoclonal antibody PCSK9 inhibitors are considered cost ineffective and there is the need to discover new effective and cheaper small molecule alternatives. PURPOSE: The methanolic and ethanolic crude extracts of Nauclea latifolia have been shown to possess anti-hyperlipidemic activity, but the chemical component(s) responsible for this activity and the mechanism of action have remained unknown. The objective of this study was therefore to identify N. latifolia constituents with anti-hyperlipidemic activity and to investigate the inhibition of PCSK9 as a probable mechanism of action. METHOD: In the present study, compounds were isolated from the ethanolic extract of the stem of N. latifolia. The alkaloids were evaluated for their DiI-LDL uptake promoting activity in HepG2 cell. The most active compound was further assessed for its effect on low density lipoprotein receptor (LDLR) and PCSK9 protein expressions by western blot. RESULTS: 3R-3,14-dihydroangustoline (5), showed a relatively good activity in promoting LDL uptake (1.26-fold). It further increased LDLR protein expression and decreased the protein expression of PCSK9 in a dose dependent manner (1-50  µM). CONCLUSION: Alkaloids from N. latifolia may serve as a source of new PCSK9 inhibitors.

Magnesium lithospermate B protects the endothelium from inflammation-induced dysfunction through activation of Nrf2 pathway.

Magnesium lithospermate B (MLB) is an active component of Salvia miltiorrhiza Radix, a traditional Chinese herb used in treating cardiovascular diseases. In this study, we investigated the protective effects of MLB against inflammation-induced endothelial dysfunction in vitro and in vivo, and the underlying mechanisms. Endothelial dysfunction was induced in human dermal microvascular endothelial cells (HMEC-1) in vitro by lipopolysaccharide (LPS, 1 µg/mL). We showed that pretreatment with MLB (10-100 µM) dose-dependently inhibited LPS-induced upregulation of inflammatory cytokines ICAM1, VCAM1, and TNFα, which contributed to reduced leukocytes adhesion and attenuation of endothelial hyperpermeability in HMEC-1 cells. SD rats were injected with LPS (10 mg/kg, ip) to induce endothelial dysfunction in vivo. We showed that pretreatment with MLB (25-100 mg/kg, ip) dose-dependently restored LPS-impaired endothelial-dependent vasodilation in superior mesenteric artery (SMA), attenuated leukocyte adhesion in mesenteric venules and decreased vascular leakage in the lungs. We further elucidated the mechanisms underlying the protective effects of MLB, and revealed that MLB pretreatment inhibited NF-κB activation through inhibition of IκBα degradation and subsequent phosphorylation of NF-κB p65 in vitro and in vivo. In HMEC-1 cells, MLB pretreatment activated the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. Knockdown of Nrf2 with siRNA abolished the inhibitory effects of MLB on IκBα degradation and ICAM1 up-regulation, which were mimicked by PKC inhibition (Gö6983) or PI3K/Akt inhibition (LY294002). In summary, our results demonstrate that MLB inhibits NF-κB activation through PKC- and PI3K/Akt-mediated Nrf2 activation in HMEC-1 cells and protects against LPS-induced endothelial dysfunction in murine model of acute inflammation.

Isocryptolepine, an indoloquinoline alkaloid from Cryptolepis sanguinolenta promotes LDL uptake in HepG2 cells

ABSTRACT About 31 percent of deaths worldwide result from atherosclerotic cardiovascular disease. Hyperlipidemia remains the major risk factor for this disease and therefore, it is necessary to identify antihyperlipidemic compounds for drug development. The crude ethanolic extract of Cryptolepis sanguinolenta (Lindl.) Schltr., Apocynaceae, has demonstrated antihyperlipidemic properties. However, the chemical constituents responsible for this action are unknown. Hence, to identify chemical constituent(s) of C. sanguinolenta with anti-hyperlipidemic effect, five indoloquinoline alkaloids were isolated and evaluated in 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl-indocarbocyanine perchlorate labeled low density lipoprotein uptake assay using HepG2 cells. The minor alkaloid, isocryptolepine, showed strong activity in promoting low lipid lipoprotein uptake by 1.85-fold. Isocryptolepine may, therefore, serve as a lead compound for future studies in the development of novel antihyperlipidemic drugs.

Cytotoxic and other withanolides from aeroponically grown Physalis philadelphica.

Eleven withanolides including six previously undescribed compounds, 16ß-hydroxyixocarpanolide, 24,25-dihydroexodeconolide C, 16,17-dehydro-24-epi-dioscorolide A, 17-epi-philadelphicalactone A, 16-deoxyphiladelphicalactone C, and 4-deoxyixocarpalactone A were isolated from aeroponically grown Physalis philadelphica. Structures of these withanolides were elucidated by the analysis of their spectroscopic (HRMS, 1D and 2D NMR, ECD) data and comparison with published data for related withanolides. Cytotoxic activity of all isolated compounds was evaluated against a panel of five human tumor cell lines (LNCaP, ACHN, UO-31, M14 and SK-MEL-28), and normal (HFF) cells. Of these, 17-epi-philadelphicalactone A, withaphysacarpin, philadelphicalactone C, and ixocarpalactone A exhibited cytotoxicity against ACHN, UO-31, M14 and SK-MEL-28, but showed no toxicity to HFF cells.