benzofurans and chalcomoracin

Diabetes is a chronic metabolic disease, whereas α-glucosidases are key enzymes involved in the metabolism of starch and glycogen. There is a long history of the use of mulberry leaf (the leaf of

Topics: Acarbose; alpha-Glucosidases; Benzofurans; Diabetes Mellitus; Glycogen; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Molecular Docking Simulation; Morus; Plant Leaves; Starch

Retinal pigment epithelial (RPE) cells are the major cell type in the epi- or sub-retinal membranes in the pathogenesis of proliferative vitreoretinopathy (PVR), which is a blinding fibrotic eye disease and still short of effective medicine. The purpose of this study is to demonstrate whether Chalocomoracin (CMR), a novel purified compound from fungus-infected mulberry leaves, is able to inhibit vitreous-induced signalling events and cellular responses intrinsic to PVR. Our studies have revealed that the CMR IC50 for ARPE-19 cells is 35.5 μmol/L at 72 hours, and that 5 μmol/L CMR inhibits vitreous-induced Akt activation and p53 suppression; in addition, we have discovered that this chemical effectively blocks vitreous-stimulated proliferation, migration and contraction of ARPE-19 cells, suggesting that CMR is a promising PVR prophylactic.

Topics: Animals; Benzofurans; Cell Line; Cell Movement; Cell Proliferation; Cells, Cultured; Epithelial Cells; Humans; Proto-Oncogene Proteins c-akt; Rabbits; Retinal Pigment Epithelium; Signal Transduction; Tumor Suppressor Protein p53; Vitreous Body

Chalcomoracin (CMR) is a kind of Diels-Alder adduct extracted from the mulberry leaves. Recent studies showed that CMR has a broad spectrum of anticancer activities and induces paraptosis in breast cancer and prostate cancer cells. In this study, we investigated the effects of CMR against human non-small cell lung cancer cells and the underlying mechanisms. We found that CMR dose-dependently inhibited the proliferation of human lung cancer H460, A549 and PC-9 cells. Furthermore, exposure to low and median doses of CMR induced paraptosis but not apoptosis, which was presented as the formation of extensive cytoplasmic vacuolation with increased expression of endoplasmic reticulum stress markers, Bip and Chop, as well as activation of MAPK pathway in the lung cancer cells. Knockdown of Bip with siRNA not only reduced the cell-killing effect of CMR, but also decreased the percentage of cytoplasmic vacuoles in H460 cells. Moreover, CMR also increased the sensitivity of lung cancer cells to radiotherapy through enhanced endoplasmic reticulum stress. In lung cancer H460 cell xenograft nude mice, combined treatment of CMR and radiation caused greatly enhanced tumor growth inhibition with upregulation of endoplasmic reticulum stress proteins and activation of pErk in xenograft tumor tissue. These data demonstrate that the anticancer activity and radiosensitization effect of CMR result from inducing paraptosis, suggesting that CMR could be considered as a potential anticancer agent and radiation sensitizer in the future cancer therapeutics.

Topics: A549 Cells; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Benzofurans; Carcinoma, Non-Small-Cell Lung; Cell Proliferation; Cell Survival; Drug Screening Assays, Antitumor; Endoplasmic Reticulum Stress; Female; Humans; Lung Neoplasms; Mice; Mice, Nude; Neoplasms, Experimental; Tumor Cells, Cultured

The Diels-Alder reaction is one of the most powerful and widely used methods in synthetic chemistry for the stereospecific construction of carbon-carbon bonds. Despite the importance of Diels-Alder reactions in the biosynthesis of numerous secondary metabolites, no naturally occurring stand-alone Diels-Alderase has been demonstrated to catalyse intermolecular Diels-Alder transformations. Here we report a flavin adenine dinucleotide-dependent enzyme, Morus alba Diels-Alderase (MaDA), from Morus cell cultures, that catalyses an intermolecular [4+2] cycloaddition to produce the natural isoprenylated flavonoid chalcomoracin with a high efficiency and enantioselectivity. Density functional theory calculations and preliminary measurements of the kinetic isotope effects establish a concerted but asynchronous pericyclic pathway. Structure-guided mutagenesis and docking studies demonstrate the interactions of MaDA with the diene and dienophile to catalyse the [4+2] cycloaddition. MaDA exhibits a substrate promiscuity towards both dienes and dienophiles, which enables the expedient syntheses of structurally diverse natural products. We also report a biosynthetic intermediate probe (BIP)-based target identification strategy used to discover MaDA.

Topics: Benzofurans; Biocatalysis; Biological Products; Cyclization; Cycloaddition Reaction; Lyases; Molecular Structure; Morus; Oxidoreductases; Stereoisomerism; Substrate Specificity

Chalocomoracin (CMR), one of the major secondary metabolites found in fungus-infected mulberry leaves, is a potent anticancer agent. However, its anticancer mechanism remains elusive. Here, we demonstrated the potent anti-tumor activity and molecular mechanism of CMR both in vitro and in vivo. We showed for the first time that CMR treatment markedly promoted paraptosis along with extensive cytoplasmic vacuolation derived from the endoplasmic reticulum, rather than apoptosis, in PC-3 and MDA-MB-231cell lines. Additional studies revealed that ectopic expression of Myc-PINK1 (PTEN-induced kinase 1), a key regulator of mitophagy, rendered LNCap cells susceptible to CMR-induced paraptosis, suggesting that the mitophagy-dependent pathway plays a crucial role in inducing paraptosis by activating PINK1. CMR treatment directly upregulated PINK1 and downregulated Alix genes in MDA-MB-231 and PC-3 cell lines. Furthermore, mitophagy signaling and paraptosis with cytoplasmic vacuolation could be blocked by antioxidant N-acetylcysteine (NAC), indicating the novel pathway was triggered by reactive oxygen species (ROS) production. An in vivo MDA-MB-231 xenograft tumor model revealed that CMR suppressed tumor growth by inducing vacuolation production through the same signal changes as those observed in vitro. These data suggest that CMR is a potential therapeutic entity for cancer treatment through a non-apoptotic pathway.

Topics: Antineoplastic Agents; Apoptosis; Benzofurans; Calcium; Calpain; Cell Proliferation; Cell Survival; Cytoplasm; Endoplasmic Reticulum Stress; Homeostasis; Humans; Membrane Potential, Mitochondrial; Mitogen-Activated Protein Kinases; Mitophagy; Oxidative Stress; PC-3 Cells; Protein Kinases; Reactive Oxygen Species

Eight Diels-Alder adducts, morbilisins A-H (1-8), a known analogue, chalcomoracin (9), together with eleven known flavonoids and 2-arylbenzofurans, were isolated from the leaves of Morus notabilis. Their structures were elucidated by extensive spectroscopic analysis, including 1D, 2D NMR, MS, and ECD data. Compounds 1, 5, and 7-9 showed inhibition against PTP1B phosphatase activity in vitro.

Topics: Benzofurans; Flavonoids; Molecular Structure; Morus; Plant Leaves; Protein Tyrosine Phosphatase, Non-Receptor Type 1

The column chromatography on silica gel, Sephadex LH-20 and semi-preparative HPLC were used to separate and purify the compounds from the EtOAc extract of medium and MeOH extract of cell cultures of Morus alba. Eight compounds were isolated. Based on physico-chemical properties and spectroscopic data, their structures were identified as isobavachalcone (1), genistein (2), norartocarpetin (3), albanin A (4), guangsangon E (5), mulberrofuran F (6), chalcomoracin (7), kuwanon J (8). Compounds 3-6 were isolated from the cell cultures of M. alba for the first time.

Topics: Benzofurans; Cell Culture Techniques; Chalcones; Chromatography, Gel; Chromatography, High Pressure Liquid; Dextrans; Genistein; Morus; Plant Leaves; Plants, Medicinal; Silica Gel; Terpenes

Bacterial enoyl-acyl carrier protein (ACP) reductase has been confirmed as a novel target for antibacterial drug development. In the screening of inhibitors of Staphylococcus aureus enoyl-ACP reductase (FabI), we found that a methanol extract of leaves of Morus alba L. potently inhibited S. aureus FabI as well as growth of S. aureus. The active principles were identified as chalcomoracin and moracin C by MS and NMR analysis. Chalcomoracin and moracin C inhibited S. aureus FabI with IC(50) of 5.5 and 83.8 µM, respectively. They also prevented the growth of S. aureus with minimum inhibitory concentration (MIC) of 4 and 32 µg/mL, respectively. Consistent with their inhibition against FabI and bacterial growth, they prevented (14)C]acetate incorporation into fatty acid in S. aureus while didn't affect protein synthesis. In this study, we reported that chalcomoracin and moracin C, potent antibacterial compounds from Morus alba, inhibited FabI and fatty acid synthesis.

Topics: Acetic Acid; Anti-Bacterial Agents; Bacterial Proteins; Benzofurans; Enoyl-(Acyl-Carrier-Protein) Reductase (NADH); Fatty Acids; Microbial Sensitivity Tests; Morus; Plant Extracts; Plant Leaves; Protein Biosynthesis; Staphylococcus aureus; Stilbenes

The synthesis of each of the heptamethyl ethers of the mulberry Diels-Alder adducts chalcomoracin (1) and mulberrofuran J (2) is described. The key steps in each approach involved a biomimetic intermolecular [4+2]-cycloaddition between a dehydroprenylphenol diene derived from an isoprenoid-substituted phenolic compound and an alpha,beta-unsaturated alkene of a chalcone as the dienophile. Critical to the success of the Diels-Alder reaction was the presence of the free phenol in the 2'-hydroxychalcone.

Topics: Benzofurans; Methyl Ethers; Molecular Structure; Stereoisomerism

Ultraviolet-B (UV-B) radiation is harmful to plants and human beings. Many secondary metabolites, like flavonoids, alkaloids, and lignin, are UV-B absorbing compounds, which can protect the genetic material of plants. Furthermore, they are active components of herbal drugs. UV-B radiation can activate the self-protective secondary metabolism system. The results of this paper provide a method to induce bioactive secondary metabolites from mulberry leaves (Morus alba L.) by UV-B irradiation in vitro. Five significantly different chromatographic peaks were found by HPLC fingerprint after induction, from which two active compounds were identified: One was chalcomoracin, a natural Diels-Alder type adduct with antibacterial activity; the other one was moracin N, which is a precursor of chalcomoracin. Their contents were 0.818 mg/g and 0.352 mg/g by dry weight, respectively.

Topics: Anti-Bacterial Agents; Benzofurans; Chromatography, High Pressure Liquid; Morus; Plant Leaves; Ultraviolet Rays

The investigation on the leaves of Morus alba L. was carried out to find the relationship of the constituents and the pharmacological activities. The isolation and purification were performed by various chromatographies such as silica gel, Sephadex LH-20, RP-C18 column chromatography and so on. Further detailed investigation on the fraction of the ethanol extract of leaves of Morus alba yielded four Diels-Alder type adducts mulberrofuran F1 (1), mulberrofuran F (2), chalcomoracin (3), kuwanon J (4), together with two chalcones morachalcone A (5), isobavachalcone (6), and three flavones norartocarpetin (7), kuwanon C (8), 6-geranylapigenin (9). Their structures were elucidated by the spectral analysis such as NMR, MS etc. Compounds 1, 6 were isolated from this plant for the first time, compounds 4-5, 7-9 were isolated from the leaves of Morus alba L. for the first time, among which 1 was a new compound. Compounds 1-5 were evaluated for the cytotoxicity against A549, Be17402, BGC823, HCT-8 and A2780 cell lines in vitro by MTT method, but only compounds 1-3 showed cytotoxicity against several human cancer cell lines.

Topics: Antineoplastic Agents, Phytogenic; Benzofurans; Cell Line, Tumor; Cell Proliferation; Chalcones; Drugs, Chinese Herbal; Flavonoids; Humans; Morus; Plant Leaves; Terpenes