Two New Metabolites from Moquiniastrum sordidum : Phytochemical Characterization and Multifaceted Bioactivity

Recent taxonomic revisions based on molecular phylogenetics transferred species from Gochnatia to Moquiniastrum, which now includes 22 species, 20 of which occur in Brazil with an extra-Amazonian distribution. Here, we report a phytochemical study of Moquiniastrum sordidum (Less.) G. Sancho. Chromatographic separation afforded eight compounds, including two new metabolites: a sesquiterpene (5) and a phenolic glycoside (8). The known compounds were identified as simiarenol (1), oleanolic acid (2), hispidulin (3), tyrosol (4), genkwanin (6), and apigenin (7). The relative configuration of compound 5 was established using pip-HSQMBC-IPAP NMR, which afforded accurate long-range 2,3JCH coupling constants. Dereplication enabled the putative annotation of 45 metabolites: 12 flavonoids, 10 chlorogenic acid derivatives, 5 hydroxycinnamic acid derivatives, 9 terpenes, and 9 others. The biological potential of the extracts and isolated metabolites was evaluated using antioxidant, cytotoxic, antimicrobial, and antileishmanial assays. The new phenolic glycoside (8) showed potent antioxidant activity (ABTS: 1111 μmol TE g–1; FRAP: 4293 μmol Fe(II) g–1). Oleanolic acid (MIC = 130 μg mL–1) and apigenin (MIC = 30 μg mL–1) showed activity against the Gram-positive bacterium Bacillus cereus. Preliminary cytotoxic screening against HCT-116 cells showed that the dichloromethane fraction inhibited proliferation by 92% at 50 μg mL–1. Antileishmanial evaluation revealed moderate activity of the crude extract, which was significantly enhanced upon fractionation, with the dichloromethane fraction showing the highest activity against intracellular amastigotes (IC50 = 8.23 μg mL–1; SI = 7.87), indicating a selective antiparasitic effect.