ABSTRACT
OBJETIVO: Esta nota técnica tem por objetivo apresentar informações sobre o uso da monolaurina na prevenção e no tratamento de pacientes com COVID-19. DOS FATOS: Trata-se de despacho proveniente do Centro de Operações de Emergências em Saúde Pública (COE) e encaminhado ao Departamento de Gestão e Incorporação de Tecnologias e Inovação em Saúde (DGITIS/SCTIE/MS). O despacho em questão apresenta um e-mail encaminhado pelo profissional Dr. Ronaldo Amaral de Paiva (vinculado à Universidade Federal de Viçosa), intitulado "Ações técnicas efetivas para o combate à Covid-19", que traz informações acerca do uso da monolaurina no tratamento da COVID-19 para análise no âmbito de suas competências e medidas julgadas pertinentes. BUSCA NA LITERATURA E SELEÇÃO DOS ESTUDOS: Com base na pergunta PICO estruturada, foram realizadas buscas nas bases de dados Medline (via PubMed) e Embase com acesso em 05 de maio de 2020. As estratégias de busca estão descritas conforme o Quadro 2 abaixo e mostram que não foram identificados estudos científicos sobre a questão de pesquisa. As plataformas de registros de ensaios clínicos ClinicalTrial.gov e International Clinical Trials Registry Platform (ICTRP), da Organização Mundial de Saúde (OMS), também foram consultadas. Foram utilizados os termos de busca: SARS-COV-2, COVID-19, 2019 novel coronavirus, 2019-nCoV, severe acute respiratory syndrome coronavirus 2, Wuhan coronavirus, COVID, monolaurin e glycerol monolaurate. Da mesma forma, nenhum estudo foi identificado em ambas as plataformas de registro. CONCLUSÕES: Embora haja evidências substanciais de ação antiviral de monoglicerídeos em vírus de RNA envelopados, não foram identificadas evidências científicas que corroborem o uso da monolaurina na prevenção ou tratamento de pacientes da COVID-19. Portanto, não foi possível aferir informações sobre um potencial efeito da substância sobre as membranas protetoras do SARS-CoV-2. Sendo assim, conclui-se que não há eficácia comprovada do uso na prevenção e tratamento da COVID-19. É prudente alertar sobre o crescente número de informações on-line, pretensamente fundadas em evidências científicas, que disseminam suposições de que produtos naturais, como o óleo de coco (23,24), teriam um efeito "protetor" contra a infecção pelo SARS-CoV-2. Não há qualquer regulamentação por nenhuma agência de vigilância sanitária nacional ou internacional para esses produtos que inclua essa finalidade de uso. Haja vista a precariedade de evidências acerca do tema, o presente documento será atualizado à medida que elas forem identificadas.
Subject(s)
Humans , Coronavirus Infections/prevention & control , Coronavirus Infections/drug therapy , Betacoronavirus/drug effects , Laurates/therapeutic use , Technology Assessment, Biomedical , Health EvaluationABSTRACT
It has been hypothesized that the therapeutic effects of artepillin C, a natural compound derived from Brazilian green propolis, are likely related to its partition in the lipid bilayer component of biological membranes. To test this hypothesis, we investigated the effects of the major compound of green propolis, artepillin C, on model membranes (small and giant unilamelar vesicles) composed of ternary lipid mixtures containing cholesterol, which display liquid-ordered (lo) and liquid-disordered (ld) phase coexistence. Specifically, we explored potential changes in relevant membrane parameters upon addition of artepillin C presenting both neutral and deprotonated states by means of small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and confocal and multiphoton excitation fluorescence microscopy. Thermotropic analysis obtained from DSC experiments indicated a loss in the lipid cooperativity of lo phase at equilibrium conditions, while at similar conditions spontaneous formation of unilamellar vesicles from SAXS experiments showed that deprotonated artepillin C preferentially located at the surface of the membrane. Time-resolved experiments using fluorescence microscopy showed that at doses above 100 µM, artepillin C in its neutral state interacted with both liquid-ordered and liquid-disordered phases, inducing curvature stress and promoting dehydration at the membrane interface.
Subject(s)
Phenylpropionates/chemistry , Lipid Bilayers/chemistry , Liposomes/chemistry , Reference Values , Temperature , Time Factors , Calorimetry, Differential Scanning , Cholesterol/chemistry , Reproducibility of Results , Microscopy, Confocal , Scattering, Small Angle , Laurates , Microscopy, Fluorescence , Models, Chemical , 2-Naphthylamine/analogs & derivativesABSTRACT
The inherent evolvability of promiscuous enzymes endows them with great potential to be artificially evolved for novel functions. Previously, we succeeded in transforming a promiscuous acylaminoacyl peptidase (apAAP) from the hyperthermophilic archaeon Aeropyrum pernix K1 into a specific carboxylesterase by making a single mutation. In order to fulfill the urgent requirement of thermostable lipolytic enzymes, in this paper we describe how the substrate preference of apAAP can be further changed from p-nitrophenyl caprylate (pNP-C8) to p-nitrophenyl laurate (pNP-C12) by protein and solvent engineering. After one round of directed evolution and subsequent saturation mutagenesis at selected residues in the active site, three variants with enhanced activity towards pNP-C12 were identified. Additionally, a combined mutant W474V/F488G/R526V/T560W was generated, which had the highest catalytic efficiency (k (cat)/K (m)) for pNP-C12, about 71-fold higher than the wild type. Its activity was further increased by solvent engineering, resulting in an activity enhancement of 280-fold compared with the wild type in the presence of 30% DMSO. The structural basis for the improved activity was studied by substrate docking and molecular dynamics simulation. It was revealed that W474V and F488G mutations caused a significant change in the geometry of the active center, which may facilitate binding and subsequent hydrolysis of bulky substrates. In conclusion, the combination of protein and solvent engineering may be an effective approach to improve the activities of promiscuous enzymes and could be used to create naturally rare hyperthermophilic enzymes.
Subject(s)
Aeropyrum , Chemistry , Archaeal Proteins , Genetics , Metabolism , Binding Sites , Biocatalysis , Caprylates , Metabolism , Cloning, Molecular , Dimethyl Sulfoxide , Chemistry , Escherichia coli , Hot Temperature , Industrial Microbiology , Methods , Kinetics , Laurates , Metabolism , Molecular Dynamics Simulation , Mutagenesis, Site-Directed , Methods , Peptide Hydrolases , Genetics , Metabolism , Protein Binding , Protein Conformation , Recombinant Proteins , Genetics , Metabolism , Solvents , Chemistry , Substrate SpecificityABSTRACT
We developed a new enzymatic-catalyzing producing process of glucose laurate monoester. In the process we used Candida antarctica lipase B-displaying Pichia pastoris whole-cells as biocatalyst, glucose as the acyl acceptor and lauric acid as the acyl donor. The product glucose laurate monoester was purified by silica gel column chromatography and preparative liquid chromatography, and identified by liquid chromatography-mass spectrometry. Then we optimized the process from various aspects, such as solvent composition, ratio of dmethyl sulfoxide to 2-Methyl-2-butanol (V/V), catalyst dosage, substrate concentration, water activity and temperature. The optimal reaction conditions were: glucose 0.5 mmol/L, lauric acid 1.0 mmol/L, ratio of 2-Methyl-2-butanol to Dmethyl sulfoxide is 7:3 in 5 mL volume, temperature 60 degrees C, the best initial water activity of whole-cells biocatalyst is 0.11. The maximum glucose conversion could be 48.7% after 72 h.