Vitamin K as a diet supplement with impact in human health: current evidence in age-related idseases

Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as cardiovascular disease, osteoarthritis, dementia, cognitive impairment, mobility disability, and frailty. Novel and more efficient nutritional and therapeutic options are urgently needed to lower the burden and the associated health care costs of these age-related diseases. Naturally occurring vitamin K comprise the phylloquinone (vitamin K1), and a series of menaquinones broadly designated as vitamin K2 that differ in source, absorption rates, tissue distribution, bioavailability, and target activity. Although vitamin K1 and K2 sources are mainly dietary, consumer preference for diet supplements is growing, especially when derived from marine resources. The aim of this review is to update the reader regarding the specific contribution and effect of each K1 and K2 vitamers in human health, identify potential methods for its sustainable and cost-efficient production, and novel natural sources of vitamin K and formulations to improve absorption and bioavailability. This new information will contribute to foster the use of vitamin K as a health-promoting supplement, which meets the increasing consumer demand. Simultaneously, relevant information on the clinical context and direct health consequences of vitamin K deficiency focusing in aging and age-related diseases will be discussed.info:eu-repo/semantics/publishedVersio

Estudo da toxicidade inerente à utilização de fármacos baseados em endoperóxidos, no tratamento da malária

Dissertação de mestrado, Ciências Farmacêuticas, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2014O composto natural artemisinina e os seus derivados, são fármacos da classe dos endoperóxidos usados há várias décadas no tratamento de malária, pois conduzem à rápida diminuição da massa de Plasmodium e apresentam elevada tolerância em humanos. [1, 2] Devido ao desenvolvimento de resistência por parte do parasita a alguns fármacos convencionais, a terapia de combinação contendo endoperóxidos é vivamente recomendada pela Organização Mundial de Saúde e tem contribuído para uma diminuição da mortalidade e morbilidade devidas à malária. [3] O potencial terapêutico das artemisininas está igualmente em estudo enquanto potenciais anti-neoplásicos, no tratamento de cancro da mama, colo-rectal e do pulmão. [2, 4] O mecanismo de ação destes endoperóxidos é baseado na ativação dos mesmos pela presença de ferro existente em células de Plasmodium e em células cancerígenas, altamente proliferativas. A sua ativação celular gera espécies radicalares, de elevada reatividade, com atividade farmacológica relativamente às células alteradas, conferindo seletividade à abordagem terapêutica. [5,6] Os alvos terapêuticos propostos são vários, sendo o seu mecanismo de ação alvo de um intenso debate científico. Apesar de muito promissores, algumas questões se levantam relativamente à segurança destes compostos, essencialmente com a possível toxicidade inerente à terapia, associada com o seu centro ativo. De facto, existem casos de neurotoxocidade e embriotoxicidade reportados em estudos com animais, apesar de não relatados no uso clínico. [2, 7-9] Relativamente à embriotoxicidade, assume-se que o benefício estimado na administração de alguns destes fármacos nos primeiros trimestres de gravidez compensam o risco associado, evitando consequências de malária tais como anemia, em ambos gestante e feto, parto prematuro, atraso do desenvolvimento embrionário, baixo peso do recém-nascido ou mesmo aborto. [10] Esta monografia pretende elencar e discutir as evidências recolhidas relativamente à potencial toxicidade de fármacos antimaláricos contendo um centro ativo endoperoxídico, abordando a temática na perspetiva da razão custo / benefício

Amentadione is a new modulating agent for osteoarthritis in an ex-vivo co-culture preclinical assay

Osteoarthritis (OA) is a whole-joint disease where inflammation interplays with extracellular matrix mineralization in a cycle that leads to its degradation. The lack of effective preventing treatments and disease modifying agents, demands new therapeutic targets and development of effective drugs.FCT: SFRH/BD/111824/2015info:eu-repo/semantics/publishedVersio

Use of an innovative system and nanotechnology-based strategy for therapeutic applications of Gla-rich protein (GRP)

Introduction: Gla-rich protein (GRP) is a vitamin K-dependent protein (VKDP) acting as a calcification inhibitor and anti-inflammatory agent in cardiovascular and articular systems, and THP1 monocyte/macrophage cells [1,2]. Calcification and inflammation processes are known to be involved in the etiology of several calcification-related chronic inflammatory diseases such as atherosclerosis, CKD and osteoarthritis, in a complex bi-directional interplay that drives disease progression. Here, we developed an innovative system to produce human c-carboxylated GRP (cGRP), and a nanotechnology strategy based on GRP loading into extracellular vesicles (EVs) as a gold standard delivery system for GRP in therapeutic applications. Materials and methods: Human GRP protein was co-expressed with c-carboxylase enzyme (GGCX), vitamin K oxidoreductase (GGCX) and furin, in the insect cell baculovirus system in the presence of vitamin K. GRP released in the cell culture media was characterized by mass spectrometry based techniques and Western blot analysis. EVs released by the insect cells overexpressing GRP were isolated by ultracentrifugation, and characterized for GRP content through TEM-immunogold staining, Western blot, ELISA, qPCR. Functional assays using isolated EVs containing GRP were performed in primary vascular smooth muscle cells (VSMCs) and THP1 monocyte/macrophage cells, for anti-mineralizing and anti-inflammatory screening.Results: GRP released in the cell culture media when co-expressed with GGCX, VKOR and furin in the presence of vitamin K, is processed at the pro-peptide and contain Gla residues. EVs released by the insect cells in this system were shown to be loaded with GRP protein and mRNA, and capable of reducing ECM calcium deposition of calcifying VSMCs and the production of TNFa in THP1 monocyte/macrophage cells stimulated with LPS. Discussion and conclusions: While the successful production of human cGRP constitutes a major achievement, this innovative methodology will open new opportunities for the production of other biological active VKDPs. Furthermore, EVs loaded with GRP were shown to have anti-mineralizing and anti-inflammatory properties, with promising therapeutic potentialities for calcification-related chronic inflammatory diseases.Portuguese Foundation for Science and Technology (EU/PID1003201)info:eu-repo/semantics/publishedVersio

Peroxides with antiplasmodial activity inhibit proliferation of Perkinsus olseni, the causative agent of Perkinsosis in bivalves

Perkinsus olseni, the causative agent of Perkinsosis, can drastically affect the survival of target marine mollusks, with dramatic economic consequences for aquaculture. P. olseni is a member of the Alveolata group, which also comprises parasites that are highly relevant for medical and veterinary sciences such as Plasmodium falciparum and Toxoplasma. P. olseni shares several unique metabolic pathways with those pathological parasites but is not toxic to humans. In this work, six antimalarially active peroxides, derived from the natural product artemisinin or synthetic trioxolanes, were synthesized and tested on P. olseni proliferation and survival. All peroxides tested revealed an inhibitory effect on P. olseni proliferation atmicromolar concentrations. The relevance of the peroxide functionality on toxicity and the effect of Fe(II)-intracellular concentration on activity were also evaluated. Results demonstrated that the peroxide functionality is the toxofore and intracellular iron concentration also proved to be a crucial co-factor on the activation of peroxides in P. olseni. These data points to a mechanismof bioactivation in P. olseni sharing similaritieswith the one proposed in P. falciparumparasites. Preliminary studies on bioaccumulation were conducted using fluorescent-labeled peroxides. Results show that synthetic trioxolanes tend to accumulate on a vacuolewhile the labeled artemisinin accumulates in the cytoplasm. Preliminary experiments on differential genes expression associated to Fe(II) transport protein (Nramp) and calcium transport protein (ATP6/SERCA) were also conducted by qPCR. Results point to a fourfold increase in expression of both genes upon exposure to trioxolanes and approximately twofold upon exposure to artemisinin derivatives. Data obtained in this investigation is relevant for better understanding of the biology of Perkinsus andmay also be important in the development of new strategies for Perkinsosis prevention and control

Structural effects on sigmatropic shifts in heteroaromatic allyl ethersElectronic supplementary information (ESI) available: selected crystal data for compound 7. See http://www.rsc.org/suppdata/p1/b1/b102674g/

In contrast to the known thermal, exclusively [3,3], O- to N- rearrangement of allyl groups in phenyltetrazoles (1, Scheme 1), the comparable migration of the allyl group in pseudosaccharyl ethers (3; Scheme 2) has been shown to proceed through both [1,3]- and [3,3]-mechanisms, 4, 5; for the pseudosaccharyl derivative of the natural product myrtenol (6; Scheme 3) only the product 7 of a [1,3]-shift has been observed; crystallographic data and theoretical calculations provide an explanation of this ease of [1,3]-isomerization and the observed selectivity as being due to conformational constraints and electronic factors

Semi-synthetic and synthetic 1,2,4-trioxaquines and 1,2,4-trioxolaquines: synthesis, preliminary SAR and comparison with acridine endoperoxide conjugates

A novel series of semi-synthetic trioxaquines and synthetic trioxolaquines were prepared, in moderate to good yields. Antimalarial activity was evaluated against both the chloroquine-sensitive 3D7 and resistant K1 strain of Plasmodium falciparum and both series of compounds were shown to be active in the low nanomolar range. For comparison the corresponding 9-amino acridine analogues were also prepared and shown to have low nanomolar activity like their quinoline counterparts

Diels–alder/thiol–olefin co-oxygenation approach to antimalarials incorporating the 2,3-dioxabicyclo[3.3.1]nonane pharmacophore

Abstract—A Diels–Alder/thiol–olefin co-oxygenation approach to the synthesis of novel bicyclic endoperoxides 17a–22b is reported. Some of these endoperoxides (e.g., 17b, 19b, 22a and 22b) have potent nanomolar in vitro antimalarial activity equivalent to that of the synthetic antimalarial agent arteflene. Iron(II)-mediated degradation of sulfone-endoperoxide 19b and spin-trapping with TEMPO provide a spin-trapped adduct 25 indicative of the formation of a secondary carbon centered radical species 24. Reactive C-radical intermediates of this type may be involved in the expression of the antimalarial effect of these bicyclic endoperoxides

Endoperoxide carbonyl falcipain 2/3 inhibitor hybrids: toward combination chemotherapy of malaria through a single chemical entity

We extend our approach of combination chemotherapy through a single prodrug entity (O’Neill et al. Angew. Chem., Int. Ed. 2004, 43, 4193) by using a 1,2,4-trioxolane as a protease inhibitor carbonylmasking group. These molecules are designed to target the malaria parasite through two independent mechanisms of action: iron(II) decomposition releases the carbonyl protease inhibitor and potentially cytotoxic C-radical species in tandem. Using a proposed target “heme”, we also demonstrate heme alkylation/carbonyl inhibitor release and quantitatively measure endoperoxide turnover in parasitized red blood cells