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The COVID-19 pandemic has caused an unprecedented health and economic crisis, highlighting the importance of developing new molecular tools to monitor and detect SARS-CoV-2. Hence, this study proposed to employ the carrageenan extracted from Gigartina skottsbergii algae as a probe for SARS-CoV-2 virus binding capacity and potential use in molecular methods. G. skottsbergii specimens were collected in the Chilean subantarctic ecoregion, and the carrageenan was extracted -using a modified version of Webber's method-, characterized, and quantified. After 24 h of incubation with an inactivated viral suspension, the carrageenan's capacity to bind SARS-CoV-2 was tested. The probe-bound viral RNA was quantified using the reverse transcription and reverse transcription loop-mediated isothermal amplification (RT-LAMP) methods. Our findings showed that carrageenan extraction from seaweed has a similar spectrum to commercial carrageenan, achieving an excellent proportion of binding to SARS-CoV-2, with a yield of 8.3%. Viral RNA was also detected in the RT-LAMP assay. This study shows, for the first time, the binding capacity of carrageenan extracted from G. skottsbergii , which proved to be a low-cost and highly efficient method of binding to SARS-CoV-2 viral particles.

The irrational use of medications has increased the incidence of microbial infections, which are a major threat to public health. Moreover, conventional therapeutic strategies are starting to become ineffective to treat these infections. Hence, there is a need to develop and characterize novel antimicrobial compounds. Phytochemicals are emerging as a safe and accessible alternative to conventional therapeutics for treating infectious diseases. Curcumin is extracted from the dried rhizome of the spice turmeric (Curcuma longa (Zingiberaceae)). However, the bioavailability of curcumin is low owing to its lipophilic property and thus has a low therapeutic efficacy in the host. A previous study synthesized structural variants of curcumin, which are called monocurcuminoids (CNs). CNs are synthesized based on the chemical structure of curcumin with only one methyl bridge. The biological activities of four previously synthesized CNs (CN59, CN63, CN67, and CN77), curcumin, and turmeric powder were examined in this study. Gas chromatography-tandem mass spectrometry analysis of curcumin and turmeric powder revealed similar peaks, which indicated the presence of curcumin in turmeric powder. The antioxidant activity of the test compounds was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays. The ABTS radical scavenging activities of the test compounds were similar to those of vitamin C. The minimum inhibitory concentration (MIC) values of the test compounds against seven microbial strains were in the range of 4.06-150 μg/mL. The MIC value was equal to minimum bactericidal concentration value for CN63 (150 μg/mL) and CN67 (120 μg/mL) against Staphylococcus aureus. The treatment combination of CN77 (8.75 or 4.37 μg/mL) and turmeric powder (9.37 or 4.68 μg/mL) exerted synergistic growth-inhibiting effects on Aeromonas hydrophila, Candida albicans, and Pseudomonas aeruginosa. Photodynamic therapy using 2X MIC of CN59 decreased the growth of Enterococcus faecalis by 4.18-fold compared to the control group and completely inhibited the growth of Escherichia coli. The results of the hemolytic assay revealed that the test compounds were not cytotoxic with half-maximal inhibitory concentration values ranging from 49.65-130.9 μM. The anticoagulant activity of most compounds was comparable to that of warfarin but higher than that of heparin. This indicated that these compounds target the intrinsic coagulation pathway. These results demonstrated that these CNs are a safe and promising alternative for curcumin., (Copyright © 2020. Published by Elsevier Masson SAS.)

Recently we have demonstrated that needle-like cationic cellulose nanocrystals (CNC-AEMA2) evoke immunological responses through NLRP3 inflammasome/IL-1β inflammatory pathway. In this study we demonstrated that curcumin, a naturally occurring polyphenolic compound isolated from Curcuma longa (Zingiberaceae), was able to suppress, at least in part, this immunological response, as observed by diminished IL-1β secretion in CNC-AEMA2-stimulated macrophages primed with LPS. Curcumin is a well-known antioxidant and anti-inflammatory natural compound and in addition to acting as "scavenger" of reactive oxygen species (ROS), it can also upregulates antioxidant enzymes. However, the mechanisms by which this natural compound exerts its protective activity is still under investigation. We hypothesize that curcumin may also affect S-glutathionylation of key proteins involved in the NLRP3 inflammasome/IL-1β pathway, and therefore impact their protein-protein interactions. The goal of this study was to investigate the effects of curcumin on the S-glutathionylation of NLRP3 induced by CNC-AEMA2 in LPS-primed mouse macrophages (J774A.1), as well as interactions among proteins of the NLRP3 inflammasome complex. Our main finding indicates that the addition of curcumin concomitantly with LPS caused the greatest decrease in NLRP3 S-glutathionylation and a respective increase in caspase-1 S-glutathionylation, which appears to favor protein-protein interactions in the NLRP3 complex. Taking together, our results suggest that, at least in part, the anti-inflammatory activity of curcumin is associated with changes in S-glutathionylation of key NLRP3 inflammasome components, and perhaps resulting in sustained complex assembly and suppression of IL-1β secretion., (Copyright © 2017 Elsevier B.V. All rights reserved.)