RESUMEN
The novel coronavirus SARS-CoV-2 has been affecting the world, causing severe pneumonia and acute respiratory syndrome, leading people to death. Therefore, the search for anti-SARS-CoV-2 compounds is pivotal for public health. Natural products may present sources of bioactive compounds; among them, flavonoids are known in literature for their antiviral activity. Siparuna species are used in Brazilian folk medicine for the treatment of colds and flu. This work describes the isolation of 3,3',4'-tri-O-methyl-quercetin, 3,7,3',4'-tetra-O-methyl-quercetin (retusin), and 3,7-di-O-methyl-kaempferol (kumatakenin) from the dichloromethane extract of leaves of Siparuna cristata (Poepp. & Endl.) A.DC., Siparunaceae, using high-speed countercurrent chromatography in addition to the investigation of their inhibitory effect against SARS-CoV-2 viral replication. Retusin and kumatakenin inhibited SARS-CoV-2 replication in Vero E6 and Calu-3 cells, with a selective index greater than lopinavir/ritonavir and chloroquine, used as control. Flavonoids and their derivatives may stand for target compounds to be tested in future clinical trials to enrich the drug arsenal against coronavirus infections. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s43450-021-00162-5.
RESUMEN
Biodiesel production has been increasing yearly in Brazil. A large amount of glycerin is generated in this process and needs a correct destination. One possible use of this glycerin in crude form is in biotechnological processes. Xanthan gum is a commercial gum used primarily in the pharmaceutical and food industries as thickener, emulsifier and stabilizer. It is synthetized by species of the bacterium Xanthomonas generally from glucose. However, current research shows that species of this bacterium have the capacity to grow and synthesize the gum using glycerin from biodiesel. The aim of this study was to produce xanthan gum using glycerin from biodiesel production in medium with different nitrogen content, named complex and simple media. The kinetics of fermentation in simple medium showed a twofold increase in gum production (3.16 kg.m-3) compared to the one in complex medium (1.46 kg.m-3) after 120 hours. The gum generated in this study showed chemical and rheological characteristics of xanthan gum. Glucose supplementation did not show an increase in xanthan production but did increase the consistency index and the behavioral index of solutions of this gum.