Introduction Mass spectrometry in natural products research has been used as a first step to identify possible chemical structures and to guide subsequent efforts to isolate novel compounds. Preparations of Ampelozizyphus amazonicus Ducke (AA) are known for their high content of saponins, especially dammarane‐type triterpenoid aglycones. In the Amazon, where it is known as “saracura‐mirá”, roots and bark are widely used for the treatment and prevention of malaria, while the wood is discarded. The extract prepared from the wood is also saponin‐rich, but its exact chemical composition has not been described. Objective This study provides information on the chemical profiling and tentative structural identification of the major compounds (saponins) present in aqueous and ethanol extracts of bark and wood of AA by mass spectrometry. Methods The strategy used to identify compounds present in all samples was ultra‐high‐performance liquid chromatography with an ultraviolet detector coupled to tandem mass spectrometry (UHPLC‐UV‐MS/MS) for the analysis of fragmentation patterns through product ion scan using MZmine 2 software. Also, direct sample injection and electrospray ionisation combined with high‐resolution mass spectrometry (DI‐ESI‐HRMS) measurements were performed. Results The extracts showed chemical similarity, and 95 saponins were tentatively identified in AA wood and bark, including 73 which are described for the first time as tentative structures for this plant species. Conclusion This research describes a useful method for the fast and simultaneous tentative identification of major saponins in AA, contributing to the study of the chemical properties of this genus and family. Furthermore, it demonstrates the importance of the qualitative dereplication process, allowing a straightforward way to propose the tentative identification of compounds.

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.

Traditional medicine shows several treatment protocols for COVID-19 based on natural products, revealing its potential as a possible source of anti-SARS-CoV-2 agents. Ampelozizyphus amazonicus is popularly used in the Brazilian Amazon as a fortifier and tonic, and recently, it has been reported to relieve COVID-19 symptoms. This work aimed to investigate the antiviral potential of A. amazonicus, focusing on the inhibition of spike and ACE2 receptor interaction, a key step in successful infection. Although saponins are the major compounds of this plant and often reported as its active principles, a polyphenol-rich extract was the best inhibitor of the spike and ACE2 interaction. Chemical characterization of A. amazonicus bark extracts by LC-DAD-APCI-MS/MS before and after clean-up steps for polyphenol removal showed that the latter play an essential role in maintaining this activity. The effects of the extracts on viral replication were also assessed, and all samples (aqueous and ethanol extracts) demonstrated in vitro activity, inhibiting viral titers in the supernatant of Calu-3 cells after 24 hpi. By acting both in the SARS-CoV-2 cell entry process and its replication, A. amazonicus bark extracts stand out as a multitarget agent, highlighting the species as a promising candidate in the development of anti-SARS-CoV-2 drugs.

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Ziziphus joazeiro Mart., Rhamnaceae, is a plant native to northeast Brazil where it is known as "juazeiro." Its bark, rich in saponins, is widely utilized in folk medicine and as a supply to produce cosmetics. Aiming at the preservation of the species and the search for an alternative vegetal raw material, the phytochemical profiles of bark and leaves were compared by chemical techniques. The foaming index and gravimetric studies indicated that, in general, bark values were approximately twice than those of the leaves. The same occurred with the hemolysis indexes. Extracts were dereplicated by liquid chromatography with diode array detection coupled to mass spectrometry analyses using an atmospheric pressure chemical ionization source, which indicated that at least 5 saponins were common to all bark and leaf samples. The direct infusion high-resolution mass spectrometry analyses revealed at least 44 different saponins distributed between the bark and leaves of the analyzed plant, of which 40 were described for the first time. The data showed that there were similarities between the studied plant organs as demonstrated by mass spectrometry, foaming index, and hemolysis indexes. Therefore, with the application of a suitable standardization procedure the leaves could be a promising source for obtaining "juazeiro-type" saponins.