Leishmaniasis is a disease impacting public health worldwide due to its high incidence, morbidity and mortality. Available treatments are costly, lengthy and toxic, not to mention the problem of parasite resistance. The development of alternative treatments is warranted and natural products demonstrate promising activity. This study investigated the activity of Connarus suberosus extracts and compounds against Leishmania species. Several C. suberosus extracts were tested against L. amazonensis promastigotes. Active and inactive extracts were analyzed by UHPLC-MS and data evaluated using a metabolomics platform, revealing an unknown neoflavonoid (connarin, 3), isolated together with the pterocarpans: hemileiocarpin (1) and leiocarpin (2). The aforementioned compounds (1–3), together with the benzoquinones: rapanone (4), embelin (5) and suberonone (6) previously isolated by our group from the same species, were tested against: (i) L. amazonensis and L. infantum promastigotes, and (ii) L. amazonensis intracellular amastigotes, with the most active compound (3) also tested against L. infantum amastigotes. Cytotoxicity against murine peritoneal macrophages was also investigated. Compounds 2 and 3 presented an IC₅₀ 33.8 μM and 11.4 μM for L. amazonensis promastigotes; and 44.3 μM and 13.3 μM for L. infantum promastigotes, respectively. For L. amazonensis amastigotes, the IC₅₀ of 2 was 20.4 μM with a selectivity index (SI) of 5.7, while the IC₅₀ of 3 was 2.9 μM with an SI of 6.3. For L. infantum amastigotes, the IC₅₀ of 3 was 7.7 μM. Compounds 2 and 3 presented activity comparable with the miltefosine positive control, with compound 3 found to be 2–4 times more active than the positive control, depending on the Leishmania species and form. The extracts and isolated compounds showed moderate toxicity against macrophages. Compounds 2 and 3 altered the mitochondrial membrane potential (ΔΨm) and neutral lipid body accumulation, while 2 also impacted plasma membrane permeabilization, culminating in cellular disorder and parasite death. Transmission electron microscopy of L. amazonensis promastigotes treated with compound 3 confirmed the presence of lipid bodies. Leiocarpin (2) and connarin (3) demonstrated antileishmanial activity. This study provides knowledge of natural products with antileishmanial activity, paving the way for prototype development to fight this neglected tropical disease.

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.

Essential oils present environmentally sustainable alternatives to conventional vector-control products. Aedes aegypti strongly impacts public health by transmitting the viruses responsible for dengue, Zika, chikungunya, and urban yellow fever. This study investigated the spatial repellency and chemical composition of 36 commercially available essential oils and 11 volatile compounds against the female Ae. aegypti mosquito using a high-throughput screening system (HITSS). Of the 36 essential oils evaluated, 30 commercial oils (83%) presented significant (P < 0.05) spatial repellency, of which 9 were classified as strong repellents (wSAI >50), 11 as medium repellents (20 < wSAI <50), and 10 as weak repellents (wSAI <20). Citronellol and menthol behaved as strong repellents, while the other 9 volatile compounds showed important repellent or attractant effects. In addition, the study identified 37 nonoxygenated compounds and 55 oxygenated compounds, totaling 92 components distributed in the 36 oils investigated. Of the 30 oils that modified Ae. aegypti behavior, 20 were strong/medium repellents, which are candidates for the development of new spatial repellent devices capable of creating vector-free areas. Additionally, our evaluation of 11 volatile compounds using the HITSS assay provides insights into better understanding structure-repellency relationships.