Strictly Positive Definite Kernels on a Product of Spheres II

We present, among other things, a necessary and sufficient condition for the strict positive definiteness of an isotropic and positive definite kernel on the cartesian product of a circle and a higher dimensional sphere. The result complements similar results previously obtained for strict positive definiteness on a product of circles [Positivity, to appear, arXiv:1505.01169] and on a product of high dimensional spheres [J. Math. Anal. Appl. 435 (2016), 286-301, arXiv:1505.03695]

Extraction of bioactive compounds from Curcuma longa L. using deep eutectic solvents: in vitro and in vivo biological activities

In this work, deep eutectic solvents (DES-based menthol and cholinium chloride) and the ethanol, temperature, and times were selected to extract bioactive compounds from the rhizome, leaves, and flowers Curcuma longa L., using ultrasound-assisted extraction. Analyzes antioxidant, flavonoids, antimicrobial, chelation Fe2+, inhibition of the cholinesterase's enzymes, cytotoxicity, and genotoxicity in Allium cepa cells were performed. The extracts showed results of iron chelation and antibacterial. Curcuma flowers and leaves' extracts inhibited food spoilage bacteria with values above 45%, with substantial iron-chelating activity above 50%. Extracts obtained by DES based on menthol and lactic acid exhibited a high percentage of inhibition of acetyl and butyryl cholinesterase. In contrast, flower extracts obtained by menthol and acetic acid showed low inhibition of cholinesterase enzyme activity. No extract showed cytotoxicity and genotoxicity. Biological activities showed a high potential for the application of these extracts in the food and pharmaceutical industries.This study was financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001. The authors thank both CAPES for the financial support, the Federal University of Paraná (UFPR) and the Federal University of Technology - Paraná (UTFPR), Labmulti-CM (UTFPR) for the technical support provided. M. R. Mafra and L. Igarashi-Mafra are grateful to the Brazilian National Council for Scientific and Technological Development (CNPq - Grant 310182/2018-2 and 308517/2018-0, respectively).info:eu-repo/semantics/publishedVersio

In vitro and in vivo evaluation of enzymatic and antioxidant activity, cytotoxicity and genotoxicity of curcumin-loaded solid dispersions

Curcumin, the main bioactive polyphenolic compound in Curcuma longa L. rhizomes has a wide range of bioactive properties. Curcumin presents low solubility in water and thus limited bioavailability, which decreases its applicability. In this study, cytotoxic effects of curcumin solid dispersions (CurSD) were evaluated against tumor (breast adenocarcinoma and lung, cervical and hepatocellular carcinoma) and non-tumor (PLP2) cells, while cytotoxic and genotoxic effects were evaluated in Allium cepa. The effect of the CurSD on the acetylcholinesterase (AChE), butyrylcholinesterase (BChE), glutathione S-transferase (GST), andmonoamine oxidase (MAO A-B) enzymes was determined, as well as its capacity to inhibit the oxidative hemolysis (OxHLIA) and the formation of thiobarbituric acid reactive substances (TBARS). CurSD are constituted by nanoparticles that are readily dispersible in water, and inhibited 24% and 64% of the AChE and BChE activity at 100μM, respectively. GST activity was inhibited at 30μM while MAO-A and B activity were inhibited at 100μM. CurSD showed cytotoxicity against all the tested tumor cell lines without toxic effects for non-tumor cells. No cytotoxic and genotoxic potential was detected with the Allium cepa test.CurSD maintained the characteristics of free curcumin on the in vitro modulation of important enzymes without appreciable toxicity.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (strategic project UID/AGR/00690/2013) and the research contracts of J. Pinela (Project AllNatt, POCI-01-0145- FEDER-030463) and R. Calhelha. To the project POCI-01-0145-FEDER- 006984 – Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT. This work was also funded by the European Regional Development Fund through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®.info:eu-repo/semantics/publishedVersio

Photobiomodulation reduces the cytokine storm syndrome associated with Covid-19 in the zebrafish model

Although the exact mechanism of the pathogenesis of COVID-19 is not fully understood, oxidative stress and the release of pro-inflammatory cytokines have been highlighted as playing a vital role in the pathogenesis of the disease. In this sense, alternative treatments are needed to reduce the inflammation caused by COVID-19. Therefore, this study aimed to investigate the potential effect of red PBM as an attractive therapy to downregulate the cytokine storm caused by COVID-19 from a zebrafish model. RT-PCR analyses and protein-protein interaction prediction among SARS-CoV-2 and Danio rerio proteins showed that rSpike was responsible for generating systemic inflammatory processes with significantly increased pro-inflammatory (il1b, il6, tnfa, and nfkbiab), oxidative stress (romo1) and energy metabolism (slc2a1a, coa1) mRNA markers, with a pattern like those observed in COVID-19 cases in humans. On the other hand, PBM treatment decreased the mRNA levels of these pro-inflammatory and oxidative stress markers compared with rSpike in various tissues, promoting an anti-inflammatory response. Conversely, PBM promotes cellular and tissue repair of injured tissues and significantly increases the survival rate of rSpike-inoculated individuals. Additionally, metabolomics analysis showed that the most impacted metabolic pathways between PBM and the rSpike-treated groups were related to steroid metabolism, immune system, and lipids metabolism. Together, our findings suggest that the inflammatory process is an incisive feature of COVID-19, and red PBM can be used as a novel therapeutic agent for COVID-19 by regulating the inflammatory response. Nevertheless, the need for more clinical trials remains, and there is a significant gap to overcome before clinical trials.publishedVersio