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BACKGROUND Since the World Health Organization (WHO) declared Coronavirus disease 2019 (COVID-19) to be a pandemic infection, important severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) non-structural proteins (nsp) have been analysed as promising targets in virtual screening approaches. Among these proteins, 3-chymotrypsin-like cysteine protease (3CLpro), also named main protease, and the RNA-dependent RNA polymerase (RdRp), have been identified as fundamental targets due to its importance in the viral replication stages. OBJECTIVES To investigate, in silico, two of the most abundant flavonoid glycosides from Dysphania ambrosioides; a medicinal plant found in many regions of the world, along with some of the putative derivatives of these flavonoid glycosides in the human organism as potential inhibitors of the SARS-CoV-2 3CLpro and RdRp. METHODS Using a molecular docking approach, the interactions and the binding affinity with SARS-CoV-2 3CLpro and RdRp were predicted for quercetin-3-O-rutinoside (rutin), kaempferol-3-O-rutinoside (nicotiflorin) and some of their glucuronide and sulfate derivatives. FINDINGS Docking analysis, based on the crystal structure of 3CLpro and RdRp, indicated rutin, nicotiflorin, and their glucuronide and sulfate derivatives as potential inhibitors for both proteins. Also, the importance of the hydrogen bond and π-based interactions was evidenced for the presumed active sites. MAIN CONCLUSIONS Overall, these results suggest that both flavonoid glycosides and their putative human metabolites can play a key role as inhibitors of the SARS-CoV-2 3CLpro and RdRp. Obviously, further researches, mainly in vitro and in vivo experiments, are necessary to certify the docking results reported here, as well as the adequate application of these substances. Furthermore, it is necessary to investigate the risks of D. ambrosioides as a phytomedicine for use against COVID-19.

Coal tar and its distilled products (e.g., creosote) are commonly applied wood preservatives and asphalt sealants that have been identified as significant sources of polycyclic aromatic hydrocarbons (PAHs) to the environment. Despite predictions that coal tar is composed of hundreds of compounds, few studies have ventured beyond measuring select PAHs with gas chromatography–mass spectrometry (GC-MS). Expanding the target analyte list will improve our capacity to gauge the inputs and impacts of organic compounds released from coal tar and its products into the environment. Employing a complementary approach with comprehensive two-dimensional gas chromatography (GC × GC) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), we analyzed residues suspected to be coal tar or creosote collected from beaches along coastal Texas in 2014. Over 3000 peaks were observed by GC × GC (compared to the 250 peaks found by our GC-MS analysis) in the whole extract of the samples. To remove PAHs and focus on less abundant compounds, we used silica-gel chromatography to isolate eight fractions. Analysis of each silica-gel fraction by GC × GC led to the tentative identification of over 6600 peaks, including numerous nitrogen-containing heterocycles. Focusing on compounds not amenable to gas chromatography, atmospheric pressure photoionization (APPI) FT-ICR MS revealed 14 000 mass spectral peaks between 150 and 900 Da, mainly aromatics and heterocycles with up to two nitrogen or three oxygen atoms per molecule. On the basis of a comparison of the FT-ICR MS data to the Boduszynski continuum, we confirmed that these samples were residues of a whole coal tar and not a distillate cut point such as creosote.

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Skin aging is a natural process of the human body that may be accelerated due to extrinsic causes. Libidibia ferrea, popularly known as jucá, is a small tree, which possesses an abundant phenolic composition with potential antioxidant and enzymatic inhibition activities. Thus, this work aimed to investigate the anti-wrinkle and anti-whitening potentials of jucá trunk bark (LFB) and pod (LFP) extracts. A comprehensive analysis of LFB and LFP phenolic composition was accomplished by means of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Effects on skin degradation were assessed by inhibitory enzymatic activity against elastase, hyaluronidase and collagenase through colorimetric assays. Cellular viability in B16F10 and primary fibroblasts were determined by Trypan Blue exclusion assay. Anti-melanogenic effects on B16F10 cells were evaluated using cellular tyrosinase, melanin content, western blot, and RT-qPCR analyses. Inhibition of matrix metalloproteinase-2 and metalloproteinase-9 (MMP-2 and MMP-9) was determined by gelatin zymography and western blot methodologies. LC-MS/MS analyses of LFB and LFP extracts allowed the characterization of 18 compounds, among them, flavonoids, phenolic acids, and secoridoids. Additionally the pod and trunk bark compositions were compared. Hyaluronidase inhibitory activity for both extracts, LFB (IC = 8.5 ± 0.8 µg/mL) and LFP (IC = 16 ± 0.5 µg/mL), was stronger than standard rutin (IC = 27.6 ± 0.06). Pro-MMP-2 was significantly inhibited by both extracts. LFB and LFP decreased the melanin content in B16F10 due to tyrosinase inhibitory activity. L. ferrea extracts has high potential as a cosmetic ingredient due to its anti-wrinkle and depigmentant effects.

Direct infusion ESI-IT-MS(n) analysis of alkaloids allowed fast recognition of alkaloidal classes previously reported in the Annonaceae family, aiding the chromatographic step and allowing a selective isolation of compounds previously not identified in the Bocageopsis genus.

Mass spectrometry monitoring was fundamental to prioritise the isolation of substances not yet identified for the Unonopsis genus, dismissing known compounds and simplifying the phytochemical study.