Alkylamides from Acmella oleracea: antinociceptive effect and molecular docking with cannabinoid and TRPV1 receptors.

Alkylamides are secondary metabolites in Acmella oleracea and display wide applications in treating several diseases. Since alkylamides can inhibit pain, this work aims to evaluate the antinociceptive profile of A. Oleracea methanolic extracts used in vivo and in silico assays. The extracts inhibited the neurogenic and inflammatory phases of the formalin test, ratifying the antinociceptive effect of alkylamides. Furthermore, the results from molecular docking demonstrated the interaction of A. oleracea alkylamides with the CB1/CB2 and TRPV1 receptors. Additionally, the crude methanolic extract of flowers did not induce potential side effects related to the classical cannabinoid tetrad: hypolocomotion and catalepsy. In conclusion, this work confirms the potential of the alkylamides of A. Oleracea as antinociceptive agents and, for the first time, correlates its effects with the endocannabinoid and vanilloid systems through in silico assays.

Flavonoids from Siparuna cristata as Potential Inhibitors of SARS-CoV-2 Replication.

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.

Diterpenes and a new benzaldehyde from the mangrove plant Rhizophora mangle

ABSTRACT This work describes the isolation, by high-speed counter-current chromatography, of the diterpenes manool, jhanol and steviol and the benzaldehyde p-oxy-2-ethylhexyl benzaldehyde from the stilt roots hexane extract of the mangrove plant Rhizophora mangle L., Rhizophoraceae. For this, a non-aqueous biphasic solvent system composed of hexane–acetonitrile–methanol 1:1:0.5 (v/v/v) was applied. As far as we know, only steviol was previously isolated in Rhizophoraceae and this is the first time that p-oxy-2-ethylhexyl benzaldehyde is reported.

Isolation of achyrobichalcone from Achyrocline satureioides by high- speed countercurrent chromatography.

Achyrobichalcone is a biflavonoid recently found in Achyrocline satureioides. This substance has unprecedented chemical structure and occurrence, but resembles other bioactive bichalcones, which have important pharmacological properties, such as anticancer activity. The major challenge for evaluation of the physicochemical and biological properties of this new molecule is the isolation step, which affects the purity and yield of the isolated product. Thus, the objective of this work was to develop a semi-preparative method for achyrobichalcone isolation from Achyrocline satureioides by high-speed countercurrent chromatography. The high-speed countercurrent chromatography separation was achieved in two steps. In the first step, an enriched fraction of achyrobichalcone from the freeze-dried extract was obtained, using the solvent system hexane-ethyl acetate-methanol-water 0.8:1:0.8:1, v/v. The purification of achyrobichalcone from the enriched fractions was achieved by further high-speed countercurrent chromatography fractionation with hexane-ethyl acetate-methanol-water 0.9:0.9:0.8:1, v/v. The final isolated product was obtained using preparative thin layer chromatography and crystallization procedure. A yellow semi-crystalline solid with purity close to 90% was obtained as the final product. The mass recovery of achyrobichalcone isolation was near 67%. The structural identification from spectroscopic and chromatographic techniques confirmed the achyrobichalcone structure. This is the first report of achyrobichalcone isolation on a semi-preparative scale by high-speed countercurrent chromatography. This method afforded achyrobichalcone in good yield and purity for further biopharmaceutical studies.