The number of documented dengue cases has increased dramatically in recent years due to transmission through the Aedes aegypti mosquito bite. Vector control remains the most effective measure to protect against this and other arboviral diseases including Zika, chikungunya and (urban) yellow fever, with an established vaccine only available for yellow fever. Although the quinone class shows potential as leading compounds for larvicide development, limited information restricts the development of optimized structures and/or formulations. Thus, in this contribution we investigated the larvicidal and pupicidal activity of three quinone compounds isolated from a Connarus suberosus root wood ethyl acetate extract together with 28 quinones from other sources. Eight quinones demonstrated larvicidal activity, of which tectoquinone (4) proved to be the most active (LC₅₀ 1.1 µg/mL). The essential residual effect parameter of four of these quinones was evaluated in laboratory trials, with tectoquinone (4) and 2-ethylanthraquinone (7) presenting the most prolonged activity. In small-scale field residual tests, tectoquinone (4) caused 100% larvae mortality over 5 days, supporting its selection for formulation trials to develop a prototype larvicide to control Ae. aegypti.

The Aedes aegypti mosquito significantly impacts public health, with vector control remaining the most efficient means of reducing the number of arboviral disease cases. This study screened the larvicidal and pupicidal activity of common edible plant extracts. Piper nigrum L. (black pepper) extract production was optimized using accelerated solvent extraction (ASE) and validated following regulatory requirements using HPLC-PDA analytical methodology to quantify its major component–piperine. Larvicidal activity was determined for the standardized P. nigrum fruit ethanol extract (LC₅₀ 1.1 µg/mL) and piperine standard (LC₅₀ 19.0 µg/mL). Furthermore, 9-day residual activity was determined for the extract (4 µg/mL) and piperine (60 µg/mL), with daily piperine quantification. Semi-field trials of solid extract formulations demonstrated 24-day activity against Ae. aegypti larvae. Thus, the standardized P. nigrum extract emerges as a potential candidate for insecticide development to control the arboviral vector.

Propolis is a chemically complex bee product whose composition and biological properties are influenced by botanical and environmental factors. This study compared eight propolis samples collected during summer and winter from four apiaries in the Zona da Mata region of Minas Gerais, Brazil. Samples were characterized by physicochemical properties, phenolic and flavonoid content, qualitative chemical profiles by UHPLC-ESI-MS/MS, and electrical impedance, while antioxidant, antibacterial, and cytotoxic activities were evaluated using complementary in vitro assays. Summer-collected samples generally exhibited higher dry extract and total phenolic content and lower wax levels, whereas flavonoid content remained comparatively stable. Differences were also observed in electrical impedance and several antioxidant responses, with total phenolic content strongly and negatively correlated with DPPH IC₅₀ values (ρ = −0.864). All extracts inhibited Staphylococcus aureus, predominantly with MIC (Minimal Inhibitory Concentration) values of 250–500 µg/mL, without detectable bactericidal activity at the concentrations tested. UHPLC-ESI-MS/MS profiling revealed qualitatively similar chemical profiles comprising phenolic and prenylated derivatives, including artepillin C, consistent with a possible contribution from Baccharis dracunculifolia. Notably, the samples from D apiary (D1 and D2) showed pronounced and selective cytotoxicity against MDA-MB-231 cells. Overall, differences in chemical, physicochemical, and biological properties were observed between the two collection periods of regional propolis.