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Twigs of Nectandra barbellata were extracted using a solution of the ionic liquid 1-butyl-3-methylimidazolium bromide (BMImBr) in H2O, assisted by microwave (MAE). After successive chromatographic steps, one sesquiterpene, costic acid, and three new related lactones, (R)-3(7)-Z-3-hexadec-21-enylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (1), (R)-3(7)-Z-3-hexadecylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (2), and (R)-3(7)-Z-3-docosylidene-5-(hydroxymethyl)tetrahydrofuran-2-one (3), were isolated. After structural elucidation using IR, UV, HRESIMS, NMR, ECD, and VCD, compounds 1-3 were tested against trypomastigote forms of Trypanosoma cruzi. The mechanism of action of bioactive isolated compounds was studied using different fluorescent-based approaches to investigate alterations of the plasma membrane, permeability/electric potential (ΔΨp), reactive oxygen species levels, mitochondria (electric membrane potential, ΔΨm/ATP levels), Ca2+ levels, and pH of the acidocalcisomes. In addition, in silico studies predicted no resemblance to pan assay interference compounds (PAINS).

Five new neocassane-like diterpenes (1-5) were isolated from the roots of Eragrostis plana. Their structures were elucidated by spectroscopic data, and the absolute configurations of the representative compounds neocassa-12(17),15-dien-3-one (2) and neocassa-12(13),15-diene-3,14-dione (5) were assigned by vibrational circular dichroism. The phytotoxic activity of compounds 3, 4, and 5 was evaluated against the germination and growth of Ipomoea grandifolia and Euphorbia heterophylla. Compound 4 exhibited the most potent activity for growth variables, resulting in the smallest radicle length of I. grandifolia and in the smallest aerial part length of E. heterophylla. Compound 5 reduced the germination speed index more effectively than the herbicide glyphosate (Roundup).

Five new neocassane-like diterpenes (

Peperomia obtusifolia, an ornamental plant from the Piperaceae family, accumulates a series of secondary metabolites with interesting biological properties. From a biosynthesis standpoint, this species produces several benzopyrans derived from orsellinic acid, which is a polyketide typically found in fungi. Additionally, the chiral benzopyrans were reported as racemic and/or as diastereomeric mixtures, which raises questions about the level of enzymatic control in the cyclization step for the formation of the 3,4-dihydro-2H-pyran moiety. Therefore, this article describes the use of shotgun proteomic and transcriptome studies as well as phytochemical profiling for the characterization of the main biosynthesis pathways active in P. obtusifolia. This combined approach resulted in the identification of a series of proteins involved in its secondary metabolism, including tocopherol cyclase and prenyltransferases. The activity of these enzymes was supported by the phytochemical profiling performed in different organs of P. obtusifolia. However, the polyketide synthases possibly involved in the production of orsellinic acid could not be identified, suggesting that orsellinic acid may be produced by endophytes intimately associated with the plant. Fil: Batista, Andrea N. L.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Dos Santos Pinto, José Roberto A.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Batista, Joao M.. Universidade Federal do São Carlos; Brasil Fil: Souza Moreira, Tatiana M.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Santoni, Mariana M.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Zanelli, Cleslei F.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Kato, Massuo J.. Universidade de Sao Paulo; Brasil Fil: López, Silvia Noelí. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Orgánica. Área Farmacognosia; Argentina Fil: Palma, Mario S.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Furlan, Maysa. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil

Gaudichaudianic acid, a prenylated chromene isolated from Piper gaudichaudianum, has been described as a potent trypanocidal compound against the Y-strain of Trypanosoma cruzi. We herein describe its isolation as a racemic mixture followed by enantiomeric resolution using chiral HPLC and determination of the absolute configuration of the enantiomers as (+)-S and (-)-R by means of a combination of electronic and vibrational circular dichroism using density functional theory calculations. Investigation of the EtOAc extract of the roots, stems, and leaves from both adult specimens and seedlings of P. gaudichaudianum revealed that gaudichaudianic acid is biosynthesized as a racemic mixture from the seedling stage onward. Moreover, gaudichaudianic acid was found exclusively in the roots of seedlings, while it is present in all organs of the adult plant. Trypanocidal assays indicated that the (+)-enantiomer was more active than its antipode. Interestingly, mixtures of enantiomers showed a synergistic effect, with the racemic mixture being the most active.