Exploring the α-amylase-inhibitory properties of tannin-rich extracts of Cytinus hypocistis on starch digestion.

Cytinus hypocistis(L.) L. is an edible parasitic plant that grows within the roots of its host. In addition to its use as famine food in the past, it is also tradidionally used for treating several illnesses such as intestinal problems, inflammations, tumors, and bleeding. This species is rich in hydrolysable tannins, compounds often associated with inhibiting starch digestion. Therefore, the present work investigated how effectively C. hypocistis tannin-rich extracts inhibited enzymes involved in starch digestion and if such effect also occurs in vivo. The latter premise was approached using the starch tolerance test in mice. Two optimized hydroethanolic extracts were used, a heat-assisted and an ultrasound-assisted extract, with known hydrolysable tannin content. Both extracts demonstrated potent inhibition of α-amylase. Inhibitions were of the mixed type with inhibitor constants in the 15 µg/mL range. The inhibition of the intestinal α-glucosidase was at least ten times less effective. The inhibition of the α-amylase was negatively affected by in vitro gastrointestinal digestion and bovine serum albumin. In vivo, both extracts inhibited starch digestion at doses between 100 and 400 mg/mL in healthy mice. The highest doses of the ultrasound and heat extracts diminished the peak glucose levels in the starch tolerance test by 46 and 59.3%, respectively. In streptozotocin diabetic mice, this inhibition occurred only at the dose of 400 mg/mL. Under this condition, diminution of the peak glucose concentration in the starch tolerance test was equal to 36.7% and 48.8% for the ultrasound and heat extracts, respectively. Maltose digestion was not inhibited by the C. hypocistis extracts. Qualitatively and quantitatively, thus, the actions of both extracts were similar. The results allow adding a new biological property to C. hypocistis, namely, the ability to decrease the hyper-glycemic excursion after a starch-rich meal, propitiating at the same time a diminished caloric intake.

Potential of plant extracts in targeting SARS-CoV-2 main protease: an in vitro and in silico study.

The deaths caused by the covid-19 pandemic have recently decreased due to a worldwide effort in vaccination campaigns. However, even vaccinated people can develop a severe form of the disease that requires ICU admission. As a result, the search for antiviral drugs to treat these severe cases has become a necessity. In this context, natural products are an interesting alternative to synthetic medicines used in drug repositioning, as they have been consumed for a long time through traditional medicine. Many natural compounds found in plant extracts have already been shown to be effective in treating viral and bacterial diseases, making them possible hits to exploit against covid-19. The objective of this work was to evaluate the antiviral activity of different plant extracts available in the library of natural products of the Universidade Estadual de Maringá, by inhibiting the SARS-CoV-2 main protease (Mpro), and by preventing viral infection in a cellular model. As a result, the extract of Cytinus hypocistis, obtained by ultrasound, showed a Mpro inhibition capacity greater than 90%. In the infection model assays using Vero cells, an inhibition of 99.6% was observed, with a selectivity index of 42.7. The in silico molecular docking simulations using the extract compounds against Mpro, suggested Tellimagrandin II as the component of C. hypocistis extract most likely to inhibit the viral enzyme. These results demonstrate the potential of C. hypocistis extract as a promising source of natural compounds with antiviral activity against covid-19.Communicated by Ramaswamy H. Sarma.

Exploring the phytochemical profile of Cytinus hypocistis (L.) L. as a source of health-promoting biomolecules behind its in vitro bioactive and enzyme inhibitory properties.

Cytinus hypocistis whole plant and its three different parts (petals, stalks, and nectar) were chemically characterised and their biological properties evaluated. A total of 17 phenolic compounds were identified, being galloyl-bis-HHDP-glucose the most abundant. All the tested extracts showed high antioxidant capacity, with the petals exhibiting the most promising results both in the OxHLIA (IC50 = 0.279 ng/mL) and TBARS (IC50 = 0.342 ng/mL) assays. For the antidiabetic and anti-tyrosinase enzyme inhibitory assays, the stalk extract presented the lowest IC50 values, 0.039 mg/mL and 0.09 mg/mL, respectively. Regarding antibacterial activity, all tested extracts displayed broad-spectrum microbial inhibition against both Gram-positive and Gram-negative bacteria. Similarly, all extracts displayed effective anti-proliferation activity against four tested tumour cell lines (NCI-H460, HeLa, HepG2, and MCF-7), with no toxicity observed for a non-tumour cell line. Considering the anti-inflammatory activity, the petals showed the highest nitric oxide inhibition (IC50 = 127 µg/mL). These results point C. hypocistis as a promising source of health-promoting biomolecules.

Glutathione peroxidase 4 and vitamin E control reticulocyte maturation, stress erythropoiesis and iron homeostasis.

Glutathione peroxidase 4 (GPX4) is unique as it is the only enzyme that can prevent detrimental lipid peroxidation in vivo by reducing lipid peroxides to the respective alcohols thereby stabilizing oxidation products of unsaturated fatty acids. During reticulocyte maturation, lipid peroxidation mediated by 15-lipoxygenase in humans and rabbits and by 12/15-lipoxygenase (ALOX15) in mice was considered the initiating event for the elimination of mitochondria but is now known to occur through mitophagy. Yet, genetic ablation of the Alox15 gene in mice failed to provide evidence for this hypothesis. We designed a different genetic approach to tackle this open conundrum. Since either other lipoxygenases or non-enzymatic autooxidative mechanisms may compensate for the loss of Alox15, we asked whether ablation of Gpx4 in the hematopoietic system would result in the perturbation of reticulocyte maturation. Quantitative assessment of erythropoiesis indices in the blood, bone marrow (BM) and spleen of chimeric mice with Gpx4 ablated in hematopoietic cells revealed anemia with an increase in the fraction of erythroid precursor cells and reticulocytes. Additional dietary vitamin E depletion strongly aggravated the anemic phenotype. Despite strong extramedullary erythropoiesis reticulocytes failed to mature and accumulated large autophagosomes with engulfed mitochondria. Gpx4-deficiency in hematopoietic cells led to systemic hepatic iron overload and simultaneous severe iron demand in the erythroid system. Despite extremely high erythropoietin and erythroferrone levels in the plasma, hepcidin expression remained unchanged. Conclusively, perturbed reticulocyte maturation in response to Gpx4 loss in hematopoietic cells thus causes ineffective erythropoiesis, a phenotype partially masked by dietary vitamin E supplementation.

Identification and Microbial Production of the Raspberry Phenol Salidroside that Is Active against Huntington's Disease.

Edible berries are considered to be among nature's treasure chests as they contain a large number of (poly)phenols with potentially health-promoting properties. However, as berries contain complex (poly)phenol mixtures, it is challenging to associate any interesting pharmacological activity with a single compound. Thus, identification of pharmacologically interesting phenols requires systematic analyses of berry extracts. Here, raspberry (Rubus idaeus, var Prestige) extracts were systematically analyzed to identify bioactive compounds against pathological processes of neurodegenerative diseases. Berry extracts were tested on different Saccharomyces cerevisiae strains expressing disease proteins associated with Alzheimer's, Parkinson's, or Huntington's disease, or amyotrophic lateral sclerosis. After identifying bioactivity against Huntington's disease, the extract was fractionated and the obtained fractions were tested in the yeast model, which revealed that salidroside, a glycosylated phenol, displayed significant bioactivity. Subsequently, a metabolic route to salidroside was reconstructed in S cerevisiae and Corynebacterium glutamicum The best-performing S cerevisiae strain was capable of producing 2.1 mm (640 mg L-1) salidroside from Glc in shake flasks, whereas an engineered C glutamicum strain could efficiently convert the precursor tyrosol to salidroside, accumulating up to 32 mm (9,700 mg L-1) salidroside in bioreactor cultivations (yield: 0.81 mol mol-1). Targeted yeast assays verified that salidroside produced by both organisms has the same positive effects as salidroside of natural origin.

Imatinib and spironolactone suppress hepcidin expression.

Disorders of iron metabolism are largely attributed to an excessive or insufficient expression of hepcidin, the master regulator of systemic iron homeostasis. Here, we investigated whether drugs targeting genetic regulators of hepcidin can affect iron homeostasis. We focused our efforts on drugs approved for clinical use to enable repositioning strategies and/or to reveal iron-related side effects of widely prescribed therapeutics. To identify hepcidin-modulating therapeutics, we re-evaluated data generated by a genome-wide RNAi screen for hepcidin regulators. We identified 'druggable' screening hits and validated those by applying RNAi of potential drug targets and small-molecule testing in a hepatocytic cell line, in primary murine and human hepatocytes and in mice. We initially identified spironolactone, diclofenac, imatinib and Suberoylanilide hydroxamic acid (SAHA) as hepcidin modulating drugs in cellular assays. Among these, imatinib and spironolactone further suppressed liver hepcidin expression in mice. Our results demonstrate that a commonly used anti-hypertensive drug, spironolactone, which is prescribed for the treatment of heart failure, acne and female hirsutism, as well as imatinib, a first-line, lifelong therapeutic option for some frequent cancer types suppress hepcidin expression in cultured cells and in mice. We expect these results to be of relevance for patient management, which needs to be addressed in prospective clinical studies.

Cytotoxicity of catechol towards human glioblastoma cells via superoxide and reactive quinones generation

It is known that the exposure to benzene in the petroleum industry causes lympho-haematopoietic cancer among workers. However, there is little data concerning the toxicity of benzene to the central nervous system. Benzene easily penetrates the brain where it is metabolized to catechol. Since catechol autoxidizes in physiological phosphate buffer, we hypothesized that it could be toxic towards glial cells due to the generation of reactive oxygen species and quinones. In this work we studied the cytotoxic properties of catechol towards human glioblastoma cells. We found that catechol was toxic towards these cells after 72 hours and this toxicity was related to the formation of quinones. Catechol at 230µM killed 50% of cells. The catechol-induced cytotoxicity was prevented by the addition of 100U superoxide dismutase, which also inhibited the formation of quinones. These data suggest that catechol induces cytotoxicity via the extracellular generation of superoxide and quinones.

Sabe-se que a exposição de trabalhadores ao benzeno na indústria petrolífera é uma causa de câncer do sistema linfo-hematopoiético. Pouco se sabe, contudo, a respeito da toxicidade do benzeno no sistema nervoso central. O benzeno penetra facilmente no cérebro, onde é metabolizado a catecol. Como o catecol se auto-oxida em tampão fosfato no pH fisiológico, supôs-se que esse composto poderia ser tóxico para células gliais por gerar espécies reativas do oxigênio e quinonas. Nesse trabalho estudou-se a citotoxicidade do catecol para células de glioblastoma humano. O catecol foi tóxico após 72 horas e essa toxicidade relacionou-se com a formação de quinonas. O catecol a 230mM matou metade das células em cultura. A toxicidade do catecol e a produção de quinonas foram inibidas por 100U de superóxido dismutase. Esses dados sugerem que a toxicidade induzida pelo catecol deve-se à produção extracelular de superóxido e quinonas reativas.

Toxicological and toxicogenetic effects of plants used in popular medicine and in cattle food

Toxicological and toxicogenetic effects of aqueous (tea) and hexanica fruit extract of Indigofera suffruticosa Mill, and hydroalcoholic root extract od Solanum agrarium Stendt. Were evaluated in Balb C male mice intraperitoneally exposed. A hepatotoxic effect was observed just for animals treated with aqueous fruit extract of I. suffruticosa. In relation to the toxicogenetic effect, just the group trreated with 12.5% of toxic dose of aqueous fruit extract of I. suffruticosa showed a statistically significant increase in the frequency of cells with chromosome aberrations (cytogenetic effect), although a slight increase was also observed for the highest dose (25% of LF50_ of hydroalcoholic root extract of S. agrarium. The results obtanied show that before S. agrarium is used as medicine and before the wide use of I. suffruticosa in cattle food, careful evaluation must be done.