Two new cytotoxic naphthoquinones from Mendoncia cowanii from the rainforest of Madagascar

Homocysteine, Thioretinaco Ozonide, and Oxidative Phosphorylation in Cancer and Aging: A Proposed Clinical Trial Protocol

The objective of the proposed clinical interventional trial is to demonstrate the efficacy of a novel therapeutic strategy in subjects with cancer and hyperhomocysteinemia. Following discovery of abnormal homocysteine thiolactone metabolism in cultured malignant cells, thioretinamide, the amide synthesized from retinoic acid and homocysteine thiolactone, and thioretinaco, the complex formed from cobalamin and thioretinamide, were demonstrated to have antineoplastic, anticarcinogenic, and anti-atherogenic properties in animal models. Retinol, ascorbate, and homocysteine thiolactone are necessary for biosynthesis of thioretinamide and thioretinaco by cystathionine synthase and for formation of thioretinaco ozonide from thioretinamide, cobalamin, and ozone. Thioretinaco ozonide is required for prevention of abnormal oxidative metabolism, aerobic glycolysis, suppressed immunity, and hyperhomocysteinemia in cancer.The pancreatic enzyme therapy of cancer promotes catabolism of proteins, nucleic acids, and glycosaminoglycans with excess homocysteinylated amino groups resulting from abnormal accumulation of homocysteine thiolactone in malignant cells. Dietary deficiencies of pyridoxal, folate, cobalamin, and nitriloside contribute to hyperhomocysteinemia in cancer, and in protein energy malnutrition. A deficiency of dietary sulfur amino acids downregulates cystathionine synthase, causing hyperhomocysteinemia.The organic sulfur compound diallyl trisulfide increases hydrogen sulfide production from homocysteine in animal models, inhibits Stat3 signaling in cancer stem cells, and produces apoptosis of malignant cells. The furanonaphthoquinone compound napabucasin inhibits Stat3 signaling and causes mitochondrial dysfunction, decreased oxidative phosphorylation, and apoptosis of malignant cells. The protocol of the proposed clinical trial in subjects with myelodysplasia consists of thioretinamide and cobalamin as precursors of thioretinaco ozonide, combined with pancreatic enzyme extracts, diallyl trisulfide, napabucasin, nutritional modification to minimize processed foods, vitamin supplements, essential amino acids, and beneficial dietary fats and proteins.

Hyperhomocysteinemia, Suppressed Immunity, and Altered Oxidative Metabolism Caused by Pathogenic Microbes in Atherosclerosis and Dementia

Many pathogenic microorganisms have been demonstrated in atherosclerotic plaques and in cerebral plaques in dementia. Hyperhomocysteinemia, which is a risk factor for atherosclerosis and dementia, is caused by dysregulation of methionine metabolism secondary to deficiency of the allosteric regulator, adenosyl methionine. Deficiency of adenosyl methionine results from increased polyamine biosynthesis by infected host cells, causing increased activity of ornithine decarboxylase, decreased nitric oxide and peroxynitrate formation and impaired immune reactions. The down-regulation of oxidative phosphorylation that is observed in aging and dementia is attributed to deficiency of thioretinaco ozonide oxygen complexed with nicotinamide adenine dinucleotide and phosphate, which catalyzes oxidative phosphorylation. Adenosyl methionine biosynthesis is dependent upon thioretinaco ozonide and adenosine triphosphate (ATP), and the deficiency of adenosyl methionine and impaired immune function in aging are attributed to depletion of thioretinaco ozonide from mitochondrial membranes. Allyl sulfides and furanonaphthoquinones protect against oxidative stress and apoptosis by increasing the endogenous production of hydrogen sulfide and by inhibiting electron transfer to the active site of oxidative phosphorylation. Diallyl trisulfide and napabucasin inhibit the signaling by the signal transducer and activator of transcription 3 (Stat3), potentially enhancing immune function by effects on T helper lymphocytes and promotion of apoptosis. Homocysteine promotes endothelial dysfunction and apoptosis by the unfolded protein response and endoplasmic reticulum stress through activation of the N-methyl D-aspartate (NMDA) receptor, causing oxidative stress, calcium influx, apoptosis and endothelial dysfunction. The prevention of atherosclerosis and dementia may be accomplished by a proposed nutritional metabolic homocysteine-lowering protocol which enhances immunity and corrects the altered oxidative metabolism in atherosclerosis and dementia.

Anticancer properties of new synthetic hybrid molecules combining naphtho[2,3-b]furan-4,9-dione or benzo[f]indole-4,9-dione motif with phosphonate subunit

In this paper we report an efficient and general synthesis of substituted 3-diethoxyphosphorylnaphtho [2,3-b]furan-4,9-diones and 3-diethoxyphosphorylbenzo [f]indole-4,9-diones which integrate the natural 1,4-naphtalenedione scaffold, present in several anticancer agents with the phosphonate moiety. The cytotoxicity of such hybrid molecules was tested against two leukemia cell lines, HL-60 and NALM-6 and against a breast adenocarcinoma MCF-7 cell line. Selected compounds were also tested on normal human cells: HUVEC and MCF-10A. In general, naphthofuran-4,9-diones showed much higher cytotoxic activity (IC50 values below 10 μM) than benzoindole-4,9-diones. The most promising 2-(2-chlorophenyl)-3-diethoxyphosphorylnaphtho [2,3-b]furan-4,9-dione, with the highest cytotoxic activity in the MTT test, was chosen for further evaluation of its anticancer potential. This compound, tested on HL-60 and MCF-7 cells inhibited cell proliferation, generated DNA damage and induced apoptosis. The suggested mechanism of its cytotoxic activity was the generation of intracellular reactive oxygen species and the induction of mitochondrial membrane potential dissipation.

Cytotoxic clerodane diterpenoids and their hydrolysis products from Casearia nigrescens from the rainforest of Madagascar

Bioassay-guided fractionation of the cytotoxic leaf and flower extract of Casearia nigrescens led to the isolation of four new clerodane diterpenoids, designated caseanigrescens A-D (1-4). These compounds were subject to hydrolysis to dialdehydes when stored in CDCl3. The structures of compounds 1-4 were determined using 1D and 2D NMR spectroscopy. All four compounds showed moderate cytotoxicity to the A2780 human ovarian cancer cell line, with an IC50 range of 0.83-1.4 microM.