Sesquiterpenes from Cultures of the Basidiomycete Clitocybe conglobata and Their 11.BETA.-Hydroxysteroid Dehydrogenase Inhibitory Activity

Four New Caryophyllene Sesquiterpenoids Isolated From Hypholoma capnoides 819

Four previously undescribed caryophyllene sesquiterpenoids (1-4) along with one known drimane sesquiterpenoid (5) were isolated from the fermentation products of the mushroom Hypholoma capnoides 819. The structures of 1-4 with rare tricyclic skeleton (6/5/4) or bicyclic skeletons (9/4) were determined on the basis of comprehensive spectroscopic data analysis, calculated NMR, ORD data, and their biosynthetic pathways. Compounds 1-5 only showed very weak cytotoxicity toward mouse microglial cells (BV2), breast cancer cells (MCF-7), and human lung cancer cells (A549) at 40 µM. In addition, none of the compounds demonstrated antibacterial activity against Staphylococcus aureus or Escherichia coli at 128 µg/mL.

Drimane-type sesquiterpenoids and triterpenoids from the whole plant of Limonium sinense with their antiproliferative and anti-inflammatory activities

Saline-tolerant medicinal plants possess novel chemical constituents with high bioactivity because of their unique secondary metabolic pathways. Limonium sinense, an aquatic plant found in the coastal wetlands of the Yellow River Delta, was collected and studied in the present work. Ten drimane-type sesquiterpenoids and four triterpenoids, including six new ones (sinenseines A-F), were isolated from a whole plant of L. sinense for the first time. Their structures, including the absolute configurations, were determined by analyzing the comprehensive spectroscopic data. In addition, twelve terpenoids, including nine sesquiterpenoids, were identified using UPLC-MS/MS and GNPS methods. All isolates were evaluated for their antiproliferative and anti-inflammatory activities. Compounds 2-4, 6, 13, and 14 showed moderate anti-tumor effects on A549, H1299, HepG2 and A2780 cells with IC50 values ranging from 35.2 ± 2.0 to 90.5 ± 3.1 μM. Furthermore, compound 1 exhibited significant anti-inflammatory activity with an IC50 value of 8.3 ± 1.2 μM against NO production in LPS-induced RAW 264.7 macrophages.

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

Drimane-type sesquiterpenoids (DMTs) are characterized by a distinctive 6/6 bicyclic skeleton comprising the A and B rings. While DMTs are commonly found in fungi and plants, their presence in bacteria has not been reported. Moreover, the biosynthetic pathways for DMTs have been primarily elucidated in fungi, with identified P450s only acting on the B ring. In this study, we isolated and characterized three bacterial DMTs, namely 3β-hydroxydrimenol (2), 2α-hydroxydrimenol (3), and 3-ketodrimenol (4), from Streptomyces clavuligerus. Through genome mining and heterologous expression, we identified a cav biosynthetic gene cluster responsible for the biosynthesis of DMTs 2-4, along with a P450, CavA, responsible for introducing the C-2 and C-3 hydroxy groups. Furthermore, the substrate scope of CavA revealed its ability to hydroxylate drimenol analogs. This discovery not only broadens the known chemical diversity of DMTs from bacteria, but also provides new insights into DMT biosynthesis in bacteria.

Isolation, (bio)synthetic studies and evaluation of antimicrobial properties of drimenol-type sesquiterpenes of Termitomyces fungi

Macrotermitinae termites have farmed fungi in the genus Termitomyces as a food source for millions of years. However, the biochemical mechanisms orchestrating this mutualistic relationship are largely unknown. To deduce fungal signals and ecological patterns that relate to the stability of this symbiosis, we explored the volatile organic compound (VOC) repertoire of Termitomyces from Macrotermes natalensis colonies. Results show that mushrooms emit a VOC pattern that differs from mycelium grown in fungal gardens and laboratory cultures. The abundance of sesquiterpenoids from mushrooms allowed targeted isolation of five drimane sesquiterpenes from plate cultivations. The total synthesis of one of these, drimenol, and related drimanes assisted in structural and comparative analysis of volatile organic compounds (VOCs) and antimicrobial activity testing. Enzyme candidates putatively involved in terpene biosynthesis were heterologously expressed and while these were not involved in the biosynthesis of the complete drimane skeleton, they catalyzed the formation of two structurally related monocyclic sesquiterpenes named nectrianolins.

Total synthesis of (+)-iresin

The first asymmetric total synthesis of (+)-iresin (4), an historically important ent-Drimane sesquiterpene lactone, was realized from aldehyde 3 via cyclic orthoester 6 in 5 steps. Notable transformations in this synthesis include a tandem trifluoroperacetic acid (TFPAA)-mediated Baeyer-Villiger oxidation-olefin epoxidation-epoxy ester cyclization, regioselective Burgess dehydration, and regioselective Fétizon oxidative lactonization.

Seven new drimane-type sesquiterpenoids from cultures of fungus Laetiporus sulphureus

Seven new drimane-type sesquiterpenoids, sulphureuines B-H (1-7), together with four known compounds (8-11), were obtained from cultures of mushroom Laetiporus sulphureus. All of these compounds were tested for their cytotoxicities against five human cancer cell lines (HL-60, SMMC-721, A-549, MCF-7, SW-480), compound 10 showed potent cytotoxic activity against HL-60, SMMC-721, A-549, SW-480, with IC50 values of 37.5, 14.8, 15.6, and 36.1μM, respectively.

Four New Sesquiterpenoids from Cultures of the Fungus Phellinidium sulphurascens

Four new sesquiterpenoids, namely 12-hydroxy-3-oxodrimenol (1), 11-hydroxyacetoxydrim-7-en-3β-ol (2), 2,6-dimethyl-7,10-epoxy-10-hydroxymethyldodeca-2,11-dien-6-ol (3), and 7,10-epoxy-2,6,10-trimethyldodeca-2,11-diene-4,6-diol (4), along with fourteen known compounds, were isolated from the cultures of Phellinidium sulphurascens. The structures of compounds 1-4 were established on the basis of extensive spectroscopic analysis. All of them were evaluated for their cytotoxic activities.

Validation of the Antidiabetic and Hypolipidemic Effects of Clitocybe nuda by Assessment of Glucose Transporter 4 and Gluconeogenesis and AMPK Phosphorylation in Streptozotocin-Induced Mice

The study was designed to investigate the effects of extract of Clitocybe nuda (CNE) on type 1 diabetes mellitus and dyslipidemia in streptozotocin- (STZ-) induced diabetic mice. Diabetes was induced by injection of STZ. Diabetic mice were randomly divided into five groups and given orally CNE (C1: 0.2, C2: 0.5, and C3: 1.0 g/kg body weight) or metformin (Metf) or vehicle for 4 weeks. STZ induction decreased in the levels of insulin, body weight, and the weight of skeletal muscle, whereas the levels of blood glucose, hemoglobin nonenzymatically (percent HbA1c), and circulating triglyceride (P < 0.001, P < 0.001, and P < 0.01, resp.) were increased. CNE decreased the levels of blood glucose, HbA1c, and triglyceride levels, whereas it increased the levels of insulin and leptin compared with the vehicle-treated STZ group. STZ induction caused a decrease in the protein contents of skeletal muscular and hepatic phosphorylation of AMP-activated protein kinase (phospho-AMPK) and muscular glucose transporter 4 (GLUT4). Muscular phospho-AMPK contents were increased in C2-, C3-, and Metf-treated groups. CNE and Metf significantly increased the muscular proteins of GLUT4. Liver phospho-AMPK showed an increase in all CNE- and Metf-treated groups combined with the decreased hepatic glucose production by decreasing phosphenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase), and 11beta hydroxysteroid dehydroxygenase (11β-HSD1) gene, which contributed to attenuating diabetic state. The study indicated that the hypoglycemic properties of CNE were related to both the increased muscular glucose uptake and the reduction in hepatic gluconeogenesis. CNE exerts hypolipidemic effect by increasing gene expressions of peroxisome proliferator-activated receptor α (PPARα) and decreasing expressions of fatty acid synthesis, including acyl-coenzyme A: diacylglycerol acyltransferase (DGAT) 2. Therefore, amelioration of diabetic and dyslipidemic state by CNE in STZ-induced diabetic mice occurred by regulation of GLUT4, PEPCK, DGAT2, and AMPK phosphorylation.

Antidiabetic and Antihyperlipidemic Effects of Clitocybe nuda on Glucose Transporter 4 and AMP-Activated Protein Kinase Phosphorylation in High-Fat-Fed Mice

The objective of this study was to evaluate the antihyperlipidemic and antihyperglycemic effects and mechanism of the extract of Clitocybe nuda (CNE), in high-fat- (HF-) fed mice. C57BL/6J was randomly divided into two groups: the control (CON) group was fed with a low-fat diet, whereas the experimental group was fed with a HF diet for 8 weeks. Then, the HF group was subdivided into five groups and was given orally CNE (including C1: 0.2, C2: 0.5, and C3: 1.0 g/kg/day extracts) or rosiglitazone (Rosi) or vehicle for 4 weeks. CNE effectively prevented HF-diet-induced increases in the levels of blood glucose, triglyceride, insulin (P < 0.001, P < 0.01, P < 0.05, resp.) and attenuated insulin resistance. By treatment with CNE, body weight gain, weights of white adipose tissue (WAT) and hepatic triacylglycerol content were reduced; moreover, adipocytes in the visceral depots showed a reduction in size. By treatment with CNE, the protein contents of glucose transporter 4 (GLUT4) were significantly increased in C3-treated group in the skeletal muscle. Furthermore, CNE reduces the hepatic expression of glucose-6-phosphatase (G6Pase) and glucose production. CNE significantly increases protein contents of phospho-AMP-activated protein kinase (AMPK) in the skeletal muscle and adipose and liver tissues. Therefore, it is possible that the activation of AMPK by CNE leads to diminished gluconeogenesis in the liver and enhanced glucose uptake in skeletal muscle. It is shown that CNE exhibits hypolipidemic effect in HF-fed mice by increasing ATGL expression, which is known to help triglyceride to hydrolyze. Moreover, antidiabetic properties of CNE occurred as a result of decreased hepatic glucose production via G6Pase downregulation and improved insulin sensitization. Thus, amelioration of diabetic and dyslipidemic states by CNE in HF-fed mice occurred by regulation of GLUT4, G6Pase, ATGL, and AMPK phosphorylation.

Two new sesquiterpenes from cultures of the basidiomycete Agaricus arvensis

Two new drimane sesquiterpenoids, 11,12-dihydroxy-15-drimeneoic acid (1) and 3α,11,15-trihydroxydrimene (2), were isolated from cultures of the basidiomycete Agaricus arvensis, together with one known compound 3β,11,12-trihydroxydrimene (3). Their structures were established by means of spectroscopic analysis.

A new drimane sesquiterpenoid glycoside from the seeds of Antiaris toxicaria

A new drimane sesquiterpenoid glycoside, named 7-drimen-3β,11-diol 3-O-β-d-glucopyranoside, was isolated from the 95% EtOH extract of the seeds of Antiaris toxicaria (Pers.) Lesch. The chemical structure was completely elucidated using a combination of 1D and 2D NMR techniques (COSY, HMQC, HMBC, and ROESY) and HR-ESI-MS analysis. The compound showed inhibitory activities toward methicillin-resistant Staphylococcus aureus (MRSA), chronic myelogenous leukemia (K562), and human hepatoma (SMMC-7721) cell lines.

Homo- and heptanor-sterols and tremulane sesquiterpenes from cultures of Phellinus igniarius

Four steroids, a homopregnene (1) and three heptanorergosterane derivatives (2-4), nine tremulane sesquiterpenes (5-13), and 18 known compounds have been isolated from cultures of the fungus Phellinus igniarius. Their structures and absolute configurations were elucidated by spectroscopic data analysis. In preliminary in vitro assays, at 10(-5) M, compounds 8, 9, 13, and 3beta-hydroxy-11,12-O-isopropyldrimene (14) showed significant vascular-relaxing activities against phenylephrine-induced vasoconstriction with relaxing rates of 35.7%, 45.4%, 46.6%, and 32.1%, respectively, as compared with the blank control.