The phytochemical investigation of Muehlenbeckia tamnifolia, collected in Loja-Ecuador, led to the isolation of nine known compounds identified as: lupeol acetate (1); cis-p-coumaric acid (2); lupeol (3); β-sitosterol (4) trans-p-coumaric acid (5); linoleic acid (6) (+)-catechin (7); afzelin (8) and quercitrin (9). The structures of the isolated compounds were determined based on analysis of NMR and MS data, as well as comparison with the literature. The hypoglycemic activity of crude extracts and isolated compounds was assessed by the ability to inhibit α-amylase and α-glucosidase enzymes. The hexane extract showed weak inhibitory activity on α-amylase, with an IC₅₀ value of 625 µg·mL⁻¹, while the other extracts and isolated compounds were inactive at the maximum dose tested. The results on α-glucosidase showed more favorable effects; the hexanic and methanolic extracts exhibited a strong inhibitory activity with IC₅₀ values of 48.22 µg·mL⁻¹ and 19.22 µg·mL⁻¹, respectively. Four of the nine isolated compounds exhibited strong inhibitory activity with IC₅₀ values below 8 µM, much higher than acarbose (377 uM). Linoleic acid was the most potent compound (IC₅₀ = 0.42 µM) followed by afzelin, (+)-catechin and quercitrin.

Plant extracts are sources of valuable compounds with biological activity, especially for the anti-proliferative activity against pathogens or tumor cells. Myricetin is a flavonoid found in several plants that has been described as an inhibitor of Human immunodeficiency virus type 1 (HIV-1) through its action against the HIV reverse transcriptase, but myricetin derivatives have not been fully studied. The aim of this study was to evaluate the anti-HIV-1 activity of glycosylated metabolites obtained from Marcetia taxifolia and derived from myricetin: myricetin rhamnoside and myricetin 3-(6-rhamnosylgalactoside). Compounds were obtained from organic extracts by maceration of aerial parts of M. taxifolia. All biological assays were performed in the MT4 cell line. Antiviral activity was measured as inhibition of p24 and reverse transcriptase with a fluorescent assay. Both flavonoids have antiviral activity in vitro, with an EC50 of 120 µM for myricetin 3-rhamnoside (MR) and 45 µM for myricetin 3-(6-rhamnosylgalactoside) (MRG), both significantly lower than the EC50 of myricetin (230 µM). Although both compounds inhibited the reverse transcriptase activity, with an IC50 of 10.6 µM for MR and 13.8 µM for MRG, myricetin was the most potent, with an IC50 of 7.6 µM, and an inhibition greater than 80%. Molecular docking approach showed correlation between the free energy of binding with the assays of enzyme inhibition. The results suggest that glycosylated moiety might enhance the anti-HIV-1 activity of myricetin, probably by favoring the internalization of the flavonoid into the cell. The inhibition of the HIV-1 reverse transcriptase is likely responsible for the antiviral activity.

The use of plants as therapeutic agents is part of the traditional medicine that is practiced by many indigenous communities in Ecuador. The aim of this study was to update a review published in 2016 by including the studies that were carried out in the period 2016–July 2021 on about 120 Ecuadorian medicinal plants. Relevant data on raw extracts and isolated secondary metabolites were retrieved from different databases, resulting in 104 references. They included phytochemical and pharmacological studies on several non-volatile compounds, as well as the chemical composition of essential oils (EOs). The tested biological activities are also reported. The potential of Ecuadorian plants as sources of products for practical applications in different fields, as well the perspectives of future investigations, are discussed in the last part of the review.

Analysis of the dichloromethane extract of the aerial parts of Croton cuneatus led to the isolation of the new glutarimide alkaloids: julocrotol (1), isojulocrotol (2), and julocrotone (3) along with the known compounds julocrotonine (4), lichexanthone (5) and selin-11-en-4α-ol (6). The structures of the new compounds were established by spectral methods. The in vitro cytotoxic activity of Compounds 1–6 was evaluated against six human tumor cells lines.