Showing papers in "Journal of Natural Products in 2015"

Countercurrent Separation of Natural Products: An Update.

Abstract: This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489–1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.

Suppression of Inflammatory Responses by Dihydromyricetin, a Flavonoid from Ampelopsis grossedentata, via Inhibiting the Activation of NF-κB and MAPK Signaling Pathways

Abstract: Ampelopsis grossedentata, an indigenous plant in southern China, has been used for treating pharyngitis in traditional Chinese medicine for hundreds of years. In this study, we explored the anti-inflammatory activity of dihydromyricetin (1), its major bioactive component, and the underlying mechanism of this action. We demonstrated that 1 suppressed the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) as well as increased the level of the anti-inflammatory cytokine interleukin-10 (IL-10) in lipopolysaccharide (LPS)-treated mice. Moreover, 1 was found to markedly inhibit the production of nitric oxide (NO) and the levels of TNF-α, IL-1β, and IL-6, whereas it increased the level of IL-10 in LPS-induced RAW 264.7 macrophage cells. Compound 1 also reduced the protein expression of inducible nitric oxide synthase (iNOS), TNF-α, and cyclooxygenase-2 (COX-2) in macrophage cells. Furthermore, 1 suppressed the phosphorylation of NF-kappa...

Vanillic Acid Inhibits Inflammatory Pain by Inhibiting Neutrophil Recruitment, Oxidative Stress, Cytokine Production, and NFκB Activation in Mice.

Abstract: Vanillic acid (1) is a flavoring agent found in edible plants and fruits. It is an oxidized form of vanillin. Phenolic compounds form a substantial part of plant foods used as antioxidants with beneficial biological activities. These compounds have received considerable attention because of their role in preventing human diseases. Especially, 1 presents antibacterial, antimicrobial, and chemopreventive effects. However, the mechanisms by which 1 exerts its anti-inflammatory effects in vivo are incompletely understood. Thus, the effect of 1 was evaluated in murine models of inflammatory pain. Treatment with 1 inhibited the overt pain-like behavior induced by acetic acid, phenyl-p-benzoquinone, the second phase of the formalin test, and complete Freund's adjuvant (CFA). Treatment with 1 also inhibited carrageenan- and CFA-induced mechanical hyperalgesia, paw edema, myeloperoxidase activity, and N-acetyl-β-D-glucosaminidase activity. The anti-inflammatory mechanisms of 1 involved the inhibition of oxidative stress, pro-inflammatory cytokine production, and NFκB activation in the carrageenan model. The present study demonstrated 1 presents analgesic and anti-inflammatory effects in a wide range of murine inflammation models, and its mechanisms of action involves antioxidant effects and NFκB-related inhibition of pro-inflammatory cytokine production.

Combining Mass Spectrometric Metabolic Profiling with Genomic Analysis: A Powerful Approach for Discovering Natural Products from Cyanobacteria.

Abstract: An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columba...

Isolation and Pharmacological Evaluation of Minor Cannabinoids from High-Potency Cannabis sativa

Abstract: Seven new naturally occurring hydroxylated cannabinoids (1–7), along with the known cannabiripsol (8), have been isolated from the aerial parts of high-potency Cannabis sativa. The structures of the new compounds were determined by 1D and 2D NMR spectroscopic analysis, GC-MS, and HRESIMS as 8α-hydroxy-Δ9-tetrahydrocannabinol (1), 8β-hydroxy-Δ9-tetrahydrocannabinol (2), 10α-hydroxy-Δ8-tetrahydrocannabinol (3), 10β-hydroxy-Δ8-tetrahydrocannabinol (4), 10α-hydroxy-Δ9,11-hexahydrocannabinol (5), 9β,10β-epoxyhexahydrocannabinol (6), and 11-acetoxy-Δ9-tetrahydrocannabinolic acid A (7). The binding affinity of isolated compounds 1–8, Δ9-tetrahydrocannabinol, and Δ8-tetrahydrocannabinol toward CB1 and CB2 receptors as well as their behavioral effects in a mouse tetrad assay were studied. The results indicated that compound 3, with the highest affinity to the CB1 receptors, exerted the most potent cannabimimetic-like actions in the tetrad assay, while compound 4 showed partial cannabimimetic actions. Compound 2, o...

Naringenin Inhibits UVB Irradiation-Induced Inflammation and Oxidative Stress in the Skin of Hairless Mice.

Abstract: Ultraviolet B (UVB) irradiation may cause inflammation- and oxidative-stress-dependent skin cancer and premature aging. Naringenin (1) has been reported to have anti-inflammatory and antioxidant properties, but its effects and mechanisms on UVB irradiation-induced inflammation and oxidative stress are still not known. Thus, the present study aimed to investigate the potential of naringenin to mitigate UVB irradiation-induced inflammation and oxidative damage in the skin of hairless mice. Skin edema, myeloperoxidase (neutrophil marker) and matrix metalloproteinase-9 (MMP-9) activity, and cytokine production were measured after UVB irradiation. Oxidative stress was evaluated by 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) scavenging ability, ferric reducing antioxidant power (FRAP), reduced glutathione levels, catalase activity, lipid peroxidation products, superoxide anion production, and gp91phox (NADPH oxidase subunit) mRNA expression by quantitative PCR. The intraperitoneal treat...

Dirigent Protein-Mediated Lignan and Cyanogenic Glucoside Formation in Flax Seed: Integrated Omics and MALDI Mass Spectrometry Imaging.

Abstract: An integrated omics approach using genomics, transcriptomics, metabolomics (MALDI mass spectrometry imaging, MSI), and bioinformatics was employed to study spatiotemporal formation and deposition of health-protecting polymeric lignans and plant defense cyanogenic glucosides. Intact flax (Linum usitatissimum) capsules and seed tissues at different development stages were analyzed. Transcriptome analyses indicated distinct expression patterns of dirigent protein (DP) gene family members encoding (-)- and (+)-pinoresinol-forming DPs and their associated downstream metabolic processes, respectively, with the former expressed at early seed coat development stages. Genes encoding (+)-pinoresinol-forming DPs were, in contrast, expressed at later development stages. Recombinant DP expression and DP assays also unequivocally established their distinct stereoselective biochemical functions. Using MALDI MSI and ion mobility separation analyses, the pinoresinol downstream derivatives, secoisolariciresinol diglucoside (SDG) and SDG hydroxymethylglutaryl ester, were localized and detectable only in early seed coat development stages. SDG derivatives were then converted into higher molecular weight phenolics during seed coat maturation. By contrast, the plant defense cyanogenic glucosides, the monoglucosides linamarin/lotaustralin, were detected throughout the flax capsule, whereas diglucosides linustatin/neolinustatin only accumulated in endosperm and embryo tissues. A putative biosynthetic pathway to the cyanogens is proposed on the basis of transcriptome coexpression data. Localization of all metabolites was at ca. 20 μm resolution, with the web based tool OpenMSI enabling not only resolution enhancement but also an interactive system for real-time searching for any ion in the tissue under analysis.

Antiviral Matrine-Type Alkaloids from the Rhizomes of Sophora tonkinensis.

Abstract: Three new matrine-type alkaloids, (+)-5α-hydroxyoxysophocarpine (1), (-)-12β-hydroxyoxysophocarpine (2), and (+)-5α-hydroxylemannine (3), along with 14 known analogues, (-)-sophocarpine (4), (-)-5α-hydroxysophocarpine (5), (-)-9α-hydroxysophocarpine (6), (+)-12α-hydroxysophocarpine (7), (-)-12β-hydroxysophocarpine (8), (+)-oxysophocarpine (9), (+)-matrine (10), (+)-sophoranol (11), (+)-9α-hydroxymatrine (12), (-)-14β-hydroxymatrine (13), (+)-oxymatrine (14), (+)-5α-hydroxyoxymatrine (15), (-)-14β-hydroxyoxymatrine (16), and (+)-sophoramine (17), were isolated from the rhizomes of Sophora tonkinensis. Their structures were elucidated via spectrometric data analyses, and the absolute configurations were established by single-crystal X-ray diffraction and ECD data. Alkaloids 2, 6, 11, and 13 exhibited antiviral activity against the Coxsackie virus B3 (CVB3), with IC50 values of 26.62-252.18 μM, and alkaloids 7, 8, and 17 inhibited influenza virus A/Hanfang/359/95 (H3N2) replication with IC50 values of 63.07-242.46 μM.

Anti-inflammatory Coumarin and Benzocoumarin Derivatives from Murraya alata

Abstract: Two new rare 8-methylbenzo[h]coumarins, muralatins A and B (1, 2), nine new C-8-substituted coumarins, muralatins C-K (3-11), and 22 known analogues (12-33) were isolated from the leaves of Murraya alata. The absolute configurations of compounds 5, 11, 23, 24, 27, 30, and 33 were assigned via comparison of their specific rotations, by Mosher's method, and by single-crystal X-ray diffraction and electronic circular dichroism (ECD) data of the in situ formed transition metal complexes. A putative biosynthesis pathway to 1 and 2 is proposed, and the chemical synthesis of 1 was accomplished through electrocyclization of 5,7-dimethoxy-8-[(Z)-3-methylbut-1,3-dienyl)]coumarin (12). Compounds 1, 2, 8, 12, and 31 showed inhibition of nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages with IC50 values of 6.0-14.5 μM.

Polyketides with α-Glucosidase Inhibitory Activity from a Mangrove Endophytic Fungus, Penicillium sp. HN29-3B1

Abstract: Five new compounds, pinazaphilones A and B (1, 2), two phenolic compounds (4, 5), and penicidone D (6), together with the known Sch 1385568 (3), (±)-penifupyrone (7), 3-O-methylfunicone (8), 5-methylbenzene-1,3-diol (9), and 2,4-dihydroxy-6-methylbenzoic acid (10) were obtained from the culture of the endophytic fungus Penicillium sp HN29-3B1, which was isolated from a fresh branch of the mangrove plant Cerbera manghas collected from the South China Sea Their structures were determined by analysis of 1D and 2D NMR and mass spectroscopic data Structures of compounds 4 and 7 were further confirmed by a single-crystal X-ray diffraction experiment using Cu Kα radiation The absolute configurations of compounds 1–3 were assigned by quantum chemical calculations of the electronic circular dichroic spectra Compounds 2, 3, 5, and 7 inhibited α-glucosidase with IC50 values of 280, 166, 22, and 144 μM, respectively, and are thus more potent than the positive control, acarbose

Lanostane Triterpenes from the Tibetan Medicinal Mushroom Ganoderma leucocontextum and Their Inhibitory Effects on HMG-CoA Reductase and α-Glucosidase.

Abstract: Sixteen new lanostane triterpenes, ganoleucoins A-P (1-16), together with 10 known tripterpenes (17-26), were isolated from the cultivated fruiting bodies of Ganoderma leucocontextum, a new member of the Ganoderma lucidum complex. The structures of the new compounds were elucidated by extensive spectroscopic analysis and chemical transformation. The inhibitory effects of 1-26 on HMG-CoA reductase and α-glucosidase were tested in vitro. Compounds 1, 3, 6, 10-14, 17, 18, 23, 25, and 26 showed much stronger inhibitory activity against HMG-CoA reductase than the positive control atorvastatin. Compounds 13, 14, and 16 presented potent inhibitory activity against α-glucosidase from yeast with IC₅₀ values of 13.6, 2.5, and 5.9 μM, respectively. In addition, the cytotoxicity of 1-26 was evaluated against the K562 and PC-3 cell lines by the MTT assay. Compounds 1, 2, 6, 7, 10, 12, 16, 18, and 25 exhibited cytotoxicity against K562 cells with IC₅₀ values in the range 10-20 μM. Paclitaxel was used as the positive control with an IC₅₀ value of 0.9 μM. This is the first report of secondary metabolites from this medicinal mushroom.

Polycyclic Polyprenylated Acylphloroglucinol Congeners Possessing Diverse Structures from Hypericum henryi.

Abstract: Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structural and bioactive diversity. In a systematic phytochemical investigation of Hypericum henryi, 40 PPAP-type derivatives, including the new compounds hyphenrones G-Q, were obtained. These compounds represent 12 different structural types, including four unusual skeletons exemplified by 5, 8, 10, and 17. The 12 different core structures found are explicable in terms of their biosynthetic origin. The structure of a known PPAP, perforatumone, was revised to hyphenrone A (5) by NMR spectroscopic and biomimetic synthesis methods. Several compounds exhibited inhibitory activities against acetylcholinesterase and human tumor cell lines. This study deals with the structural diversity, function, and biogenesis of natural PPAPs.

Strain prioritization for natural product discovery by a high throughput real-time pcr method

Abstract: A high throughput method for identifying organisms which produce agents or classes of compounds. The method allows for the prioritizing or identifying those organisms having the most optimal success in producing the compound.

Class I and Class II Lanthipeptides Produced by Bacillus spp.

Abstract: The increasing number of multidrug-resistant pathogens, along with the small number of new antimicrobials under development, leads to an increased need for novel alternatives. Class I and class II lanthipeptides (also known as lantibiotics) have been considered promising alternatives to classical antibiotics. In addition to their relevant medical applications, they are used as probiotics, prophylactics, preservatives, and additives in cosmetics and personal-care products. The genus Bacillus is a prolific source of bioactive compounds including ribosomally and nonribosomally synthesized antibacterial peptides. Accordingly, there is significant interest in the biotechnological potential of members of the genus Bacillus as producers of antimicrobial lanthipeptides. The present review focuses on aspects of the biosynthesis, gene cluster organization, structure, antibacterial spectrum, and bioengineering approaches of lanthipeptides produced by Bacillus strains. Their efficacy and potency against some clinically relevant strains, including MRSA and VRE, are also discussed. Although no lanthipeptides are currently in clinical use, the information herein highlights the potential of these compounds.

Ervatamines A-I, Anti-inflammatory Monoterpenoid Indole Alkaloids with Diverse Skeletons from Ervatamia hainanensis.

Abstract: Nine new monoterpenoid indole alkaloids, ervatamines A–I (1–9), and five known ones (10–14), were isolated from Ervatamia hainanensis. The new structures were elucidated by extensive spectroscopic analysis and comparison to known compounds. Their absolute configurations were determined by various methods including computational methods, X-ray diffraction analysis, and electronic circular dichroism spectroscopy, as well as chemical transformations. Ervatamine A (1) is a ring-C-contracted ibogan-type monoterpenoid indole alkaloid with an unusual 6/5/6/6/6 pentacyclic rearranged ring system. Ervatamines B–E (2–5) display a nitrogen-containing 9/6 ring system, which is rarely observed in nature. The epimeric ervatamines B (2) and C (3) possess a 22-nor-monoterpenoid indole alkaloid carbon skeleton, which was only found in deformylstemmadenine. Compounds 10 and 14 exhibited significant anti-inflammatory activities, with IC50 values of 25.5 and 41.5 μM, respectively, while the IC50 value of indomethacin as a po...

Bisthiodiketopiperazines and Acorane Sesquiterpenes Produced by the Marine-Derived Fungus Penicillium adametzioides AS-53 on Different Culture Media

Abstract: Chemical investigation of the marine-sponge-derived fungus Penicillium adametzioides AS-53 resulted in the identification of two new bisthiodiketopiperazine derivatives, adametizines A (1) and B (2), from cultivation in a liquid potato-dextrose broth (PDB) culture medium, whereas two new acorane sesquiterpenes, adametacorenols A (3) and B (4), were isolated from a rice solid culture medium. The structures of these compounds were elucidated on the basis of spectroscopic analysis. The absolute configuration of compound 1 was determined by X-ray crystallographic analysis, and that of 3 was determined by modified Mosher's method. Compound 1 exhibited lethality against brine shrimp (Artemia salina) with an LD50 value of 4.8 mu M and inhibitory activities against Staphyloccocus aureus, Aeromonas hydrophilia, Vibrio spp. V. harveyi and V. parahaemolyticus, and Gaeumannomyces graminis with minimum inhibitory concentration values of 8, 8, 32, 8, and 16 mu g/mL, respectively. Chlorination at C-7 significantly increased the brine shrimp lethality and antimicrobial activity of the bisthiodiketopiperazines.

Protostane Triterpenoids from the Rhizome of Alisma orientale Exhibit Inhibitory Effects on Human Carboxylesterase 2.

Abstract: Twelve new and 10 known protostane triterpenoids were isolated from the rhizome of Alisma orientale. Their structures were elucidated based on physical data analyses, including UV, HRESIMS, NMR experiments ((1)H, (13)C NMR, (1)H-(1)H COSY, HSQC, HMBC, and NOESY), and induced electronic circular dichroism. New compounds 1-12 were classified as protostanes (1-10), 29-norprotostane (11), and 24-norprotostane (12) by structure analyses. Furthermore, the inhibitory effects on human carboxylesterases (hCE-1, hCE-2) of compounds 1-22 were evaluated. Compounds 2, 6, 9, and 11 showed moderate inhibitory activities and were selective toward hCE-2 enzymes, with IC50 values of 8.68, 4.72, 4.58, and 2.02 μM, respectively. The inhibition kinetics of compound 11 toward hCE-2 were established, and the Ki value was determined as 1.76 μM using a mixed inhibition model. The interaction of bioactive compound 11 with hCE-2 was shown using molecular docking.

Versixanthones A-F, Cytotoxic Xanthone-Chromanone Dimers from the Marine-Derived Fungus Aspergillus versicolor HDN1009.

Abstract: Six unusual xanthone-chromanone dimers, versixanthones A-F (1-6), featuring different formal linkages of tetrahydroxanthone and 2,2-disubstituted chroman-4-one monomers, were isolated from a culture of the mangrove-derived fungus Aspergillus versicolor HDN1009. The absolute configurations of 1-6, representing the central and axial chirality elements or preferred helicities, were established by a combination of X-ray diffraction analysis, chemical conversions, and TDDFT-ECD calculations. The interconversion of different biaryl linkages between 1 and 4 and between 2 and 3 in DMSO by a retro-oxa-Michael mechanism provided insight into the formation of the xanthone-chromanone dimers and supported the assignments of their absolute configurations. Compounds 1-6 exhibited cytotoxicities against the seven tested cancer cell lines, with the best IC50 value of 0.7 μM. Compound 5 showed further inhibitory activity against topoisomerase I.

Insulin-Mimetic Selaginellins from Selaginella tamariscina with Protein Tyrosine Phosphatase 1B (PTP1B) Inhibitory Activity

Abstract: As part of an ongoing search for new antidiabetic agents from medicinal plants, three new (2, 4, and 5) and two known selaginellin derivatives (1 and 3) were isolated from a methanol extract of Selaginella tamariscina. The structures of the new compounds were determined by spectroscopic data analysis. All isolates showed strong glucose uptake stimulatory effects in 3T3-L1 adipocyte cells at a concentration of 5 μM. Furthermore, these compounds were found to possess inhibitory effects on PTP1B enzyme activity with IC50 values ranging from 4.6 ± 0.1 to 21.6 ± 1.5 μM. Compound 2 showed the greatest potency, with an IC50 value of 4.6 ± 0.1 μM, when compared with the positive control (ursolic acid, IC50 = 3.5 ± 0.1 μM). Therefore, these selaginellin derivatives may have value as new lead compounds for the development of agents against type 2 diabetes.

Spirotetronate Polyketides as Leads in Drug Discovery

Abstract: The discovery of chlorothricin (1) defined a new family of microbial metabolites with potent antitumor antibiotic properties collectively referred to as spirotetronate polyketides. These microbial metabolites are structurally distinguished by the presence of a spirotetronate motif embedded within a macrocyclic core. Glycosylation at the periphery of this core contributes to the structural complexity and bioactivity of this motif. The spirotetronate family displays impressive chemical structures, potent bioactivities, and significant pharmacological potential. This review groups the family members based on structural and biosynthetic considerations and summarizes synthetic and biological studies that aim to elucidate their mode of action and explore their pharmacological potential.

Antimicrobial Phenolic Bisabolanes and Related Derivatives from Penicillium aculeatum SD-321, a Deep Sea Sediment-Derived Fungus.

Abstract: Three new phenolic bisabolane sesquiterpenes, peniciaculins A (1) and B (2) and (7S)-(-)-10-hydroxysydonic acid (3), together with a new nor-bisabolane derivative, 1-hydroxyboivinianin A (4), as well as six known bisabolanes (5-10), were identified from the culture of Penicillium aculeatum SD-321, a fungus isolated from deep-sea sediments. The structures of these compounds were mainly determined by analysis of spectroscopic data, and the absolute configurations of compounds 1-4 were established by comparing their ECD spectra with those of known analogues or by TDDFT-ECD calculations. Compound 1 represents the first example of a bisabolane analogue linked to a diphenyl ether moiety via an ether bond, while compound 2 appears to be the first dimeric bisabolane analogue where the two monomers are coupled to each other via an ester bond. The isolated compounds were evaluated for antimicrobial activity against 10 human and aquatic pathogenic bacteria and three plant-pathogenic fungi.

Magnetic Ligand Fishing as a Targeting Tool for HPLC-HRMS-SPE-NMR: α-Glucosidase Inhibitory Ligands and Alkylresorcinol Glycosides from Eugenia catharinae.

Abstract: A bioanalytical platform combining magnetic ligand fishing for α-glucosidase inhibition profiling and HPLC-HRMS-SPE-NMR for structural identification of α-glucosidase inhibitory ligands, both directly from crude plant extracts, is presented. Magnetic beads with N-terminus-coupled α-glucosidase were synthesized and characterized for their inherent catalytic activity. Ligand fishing with the immobilized enzyme was optimized using an artificial test mixture consisting of caffeine, ferulic acid, and luteolin before proof-of-concept with the crude extract of Eugenia catharinae. The combination of ligand fishing and HPLC-HRMS-SPE-NMR identified myricetin 3-O-α-L-rhamnopyranoside, myricetin, quercetin, and kaempferol as α-glucosidase inhibitory ligands in E. catharinae. Furthermore, HPLC-HRMS-SPE-NMR analysis led to identification of six new alkylresorcinol glycosides, i.e., 5-(2-oxopentyl)resorcinol 4-O-β-D-glucopyranoside, 5-propylresorcinol 4-O-β-D-glucopyranoside, 5-pentylresorcinol 4-O-[α-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, 5-pentylresorcinol 4-O-β-D-glucopyranoside, 4-hydroxy-3-O-methyl-5-pentylresorcinol 1-O-β-D-glucopyranoside, and 3-O-methyl-5-pentylresorcinol 1-O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranoside.

Callyaerins from the Marine Sponge Callyspongia aerizusa: Cyclic Peptides with Antitubercular Activity

Abstract: Chemical investigation of the Indonesian sponge Callyspongia aerizusa afforded five new cyclic peptides, callyaerins I-M (1-5), along with the known callyaerins A-G (6-12). The structures of the new compounds were unambiguously elucidated on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. In addition, the structures of callyaerins D (9), F (11), and G (12), previously available in only small amounts, have been reinvestigated and revised. All compounds were tested in vitro against Mycobacterium tuberculosis, as well as against THP-1 (human acute monocytic leukemia) and MRC-5 (human fetal lung fibroblast) cell lines, in order to assess their general cytotoxicity. Callyaerins A (6) and B (7) showed potent anti-TB activity with MIC₉₀ values of 2 and 5 μM, respectively. Callyaerin C (8) was found to be less active, with an MIC₉₀ value of 40 μM. Callyaerin A (6), which showed the strongest anti-TB activity, was not cytotoxic to THP-1 or MRC-5 cells (IC₅₀ > 10 μM), which highlights the potential of these compounds as promising anti-TB agents.

Antinociceptive grayanoids from the roots of Rhododendron molle.

Abstract: Nine new grayanoids (1–9), together with 11 known compounds, were isolated from the roots of Rhododendron molle. The structures of the new compounds (1–9) were determined on the basis of spectroscopic analysis, including HRESIMS, and 1D and 2D NMR data. Compounds 4, 6, 12, and 14–20 showed significant antinociceptive activities in an acetic acid-induced writhing test. In particular, 14 and 15 were found to be more potent than morphine for both acute and inflammatory pain models and 100-fold more potent than gabapentin in a diabetic neuropathic pain model.

Absolute Configuration and Conformational Study of Psammaplysins A and B from the Balinese Marine Sponge Aplysinella strongylata

Abstract: The absolute configuration of psammaplysin A (1) has been assigned as (6R,7R) using experimental and calculated electronic circular dichroism (ECD) data and NMR analysis of MPA esters prepared from the acetamide derivative of 1. Detailed conformational analyses of a truncated model compound of 1 with an in vacuo method and with the PCM solvent model for MeOH have identified the major conformers and factors governing the ECD spectrum of 1. The correlation of the ECD data with the stereochemistry of 1 allows configurational assignment of related psammaplysin analogues on the basis of their ECD spectra.

Endophytic Diaporthe sp. LG23 Produces a Potent Antibacterial Tetracyclic Triterpenoid

Abstract: A new lanostanoid, 19-nor-lanosta-5(10),6,8,24-tetraene-1α,3β,12β,22S-tetraol (1), characterized by the presence of an aromatic B ring and hydroxylated at C-1, C-3, C-12, and C-22, was isolated from an endophytic fungus, Diaporthe sp. LG23, inhabiting leaves of the Chinese medicinal plant Mahonia fortunei. Six biosynthetically related known steroids were also isolated in parallel. Their structures were confirmed on the basis of detailed spectroscopic analysis in conjunction with the published data. Compound 1, an unusual fungus-derived 19-nor-lanostane tetracyclic triterpenoid with an aromatic B-ring system, exhibited pronounced antibacterial efficacy against both Gram-positive and -negative bacteria, especially the clinical isolates of Streptococcus pyogenes and Pseudomonas aeruginosa as well as a human pathogenic strain of Staphylococcus aureus. Our results reveal the potential of endophytes not only in conferring host fitness but also in contributing toward traditional host plant medicines.

Anti-parasitic Guanidine and Pyrimidine Alkaloids from the Marine Sponge Monanchora arbuscula.

Abstract: HPLC-UV-ELSD-MS-guided fractionation of the anti-parasitic extract obtained from the marine sponge Monanchora arbuscula, collected off the southeastern coast of Brazil, led to the isolation of a series of guanidine and pyrimidine alkaloids. The pyrimidines monalidine A (1) and arbusculidine A (7), as well as the guanidine alkaloids batzellamide A (8) and hemibatzelladines 9-11, represent new minor constituents that were identified by analysis of spectroscopic data. The total synthesis of monalidine A confirmed its structure. Arbusculidine A (7), related to the ptilocaulin/mirabilin/netamine family of tricyclic guanidine alkaloids, is the first in this family to possess a benzene ring. Batzellamide A (8) and hemibatzelladines 9-11 represent new carbon skeletons that are related to the batzelladines. Evaluation of the anti-parasitic activity of the major known metabolites, batzelladines D (12), F (13), L (14), and nor-L (15), as well as of synthetic monalidine A (1), against Trypanosoma cruzi and Leishmania infantum is also reported, along with a detailed investigation of parasite cell-death pathways promoted by batzelladine L (14) and norbatzelladine L (15).

Antiviral Activity of Diterpene Esters on Chikungunya Virus and HIV Replication.

Abstract: Recently, new daphnane, tigliane, and jatrophane diterpenoids have been isolated from various Euphorbiaceae species, of which some have been shown to be potent inhibitors of chikungunya virus (CHIKV) replication. To further explore this type of compound, the antiviral activity of a series of 29 commercially available natural diterpenoids was evaluated. Phorbol-12,13-didecanoate (11) proved to be the most potent inhibitor, with an EC50 value of 6.0 ± 0.9 nM and a selectivity index (SI) of 686, which is in line with the previously reported anti-CHIKV potency for the structurally related 12-O-tetradecanoylphorbol-13-acetate (13). Most of the other compounds exhibited low to moderate activity, including an ingenane-type diterpene ester, compound 28, with an EC50 value of 1.2 ± 0.1 μM and SI = 6.4. Diterpene compounds are known also to inhibit HIV replication, so the antiviral activities of compounds 1–29 were evaluated also against HIV-1 and HIV-2. Tigliane- (4β-hydroxyphorbol analogues 10, 11, 13, 15, 16, an...

Bioactive Metabolites from the Fruits of Psoralea corylifolia

Abstract: Twenty-four metabolites, including seven new compounds (1–7), were isolated from the dried fruits of Psoralea corylifolia. On the basis of combined spectroscopic and chemical analysis, the new compounds were determined to be six flavonoids (1–6) and a meroterpenoid (7). The absolute configurations of the natural products obtained, including the previously undetermined 16 and 17, were assigned by several methods, such as NOE spectroscopy, optical rotation, and CD spectroscopy. Several of these compounds exhibited moderate inhibitory activity toward Staphylococcus mutans-derived SrtA (2, 6, and 16) and significant stimulation of SIRT1 activity (2, 3, and 15).

(±)-Acortatarinowins A–F, Norlignan, Neolignan, and Lignan Enantiomers from Acorus tatarinowii

Abstract: Three pairs of new 8-O-4'-type dinorneolignan enantiomers, (±)-acortatarinowins A-C (1a/1b-3a/3b), a pair of new 8-O-4'-type (4a/4b) and a pair of rare C7-C8'-type (5a/5b) neolignan enantiomers, (±)-acortatarinowins D and E, and a pair of new furofuran-type lignan enantiomers, (±)-acortatarinowin F (6a/6b), along with two pairs of known lignan enantiomers (7a/7b and 8a/8b), were obtained from the rhizomes of Acorus tatarinowii. The separation of 1-8 by chiral HPLC using a Daicel IC column led to the isolation of eight pairs of enantiomers, 1a/1b-8a/8b, which had variable enantiomeric excess (ee) values of approximately 66, 71, 63, 60, 0, 38, 48, and 75%, respectively. The structures were elucidated by extensive spectroscopic and chemical methods, and their absolute configurations were determined by a combined analysis of single-crystal X-ray diffraction and a modified Mosher's method, assisted by experimental and calculated electronic circular dichroism data. Among them, compounds 1a, 3a, 6b, 8a, and 8b showed weak inhibitory activities against NO production in activated macrophages with IC50 values ranging from 23.3 to 38.0 μM, respectively.