Aedes aegypti is a vector responsible for the transmission of various arboviruses and is considered by the World Health Organization to be one of the main public health problems in the world. This study evaluated the larvicidal and oviposition activity of essential oils from Abies sibirica, Pogostemon cablin and Juniperus communis and their formulations. Chromatographic analysis by GCMS identified a total of 28, 52 and 18 compounds for the oils of the species A. sibirica, J. communis and P. cablin, respectively. The larvicidal bioassays showed an LC₅₀ of 67.53 ppm, 92.45 ppm and 35.95 ppm, respectively, for A. sibirica (A), J. communis (J) and P. cablin (P) as well as their binary (J + P, 39.50 ppm; A + P, 51.64 ppm) and ternary (A + J + P, 66.99 ppm) formulations. These oils and formulations also showed deterrent activity at the larvicidal concentrations tested (A. sibirica: OAI: −0.41; J. communis: OAI: −0.31; P. cablin: OAI: −0.62; A + J + P: −0.30; A + P: −0.68; A + J: −0.29; and J + P: −0.30). The oils and their formulations are a potential larvicidal source for mitigating the proliferation of diseases by this vector.

The mosquito Aedes aegypti is the vector responsible for the transmission of important arboviruses such as dengue fever, Chikungunya, Zika virus, and yellow fever. These diseases affect millions of people and exert impacts on healthcare systems throughout the world. Given the increasing resistance to synthetic insecticides, essential oils from plants constitute an ecologically viable alternative for the control of this vector. The aim of the present study was to investigate the larvicidal activity of the essential oil (EO), aqueous extract, rutin, and hydrolate from the leaves of Myrciaria floribunda against Aedes aegypti larvae in the initial L4 stage. The yield of EO was 0.47%. Thirty-seven chemical constituents were identified and quantified using chromatographic methods. The major constituents were (E)-caryophyllene (27.35%), 1,8-cineole (11.25%), β-selinene (4.92%), and α-muurolene (4.92%). In the larvicidal tests, the lethal concentration (LC₅₀) was 201.73 ppm for the essential oil, 15.85% for the aqueous extract, and 22.46 ppm for rutin. The hydrolate had no larvicidal activity. The compounds that exhibited larvicidal activity against Aedes aegypti constitute a promising option for the development of natural formulations to diminish the propagation of this vector.

The spread of antibiotic-resistant pathogens had motivated the search for plant-derived antimicrobial agents, such as essential oils. This work investigated the antibacterial, antifungal and antibiofilm properties of the essential oil from the inflorescence of Etlingera elatior and its major compounds. Dodecanal (42.46%) and 1-dodecanol (25.84%) were the major compounds. The oil, dodecanal and 1-dodecanol were active against Staphylococcus aureus, with minimum bactericidal concentrations of 124, 31 and 62 µg mL-1, respectively. For Pseudomonas aeruginosa, the essential oil had an inhibitory effect against a multidrug resistant isolate (minimum inhibitory concentration (MIC): 4,000 µg mL-1). Dodecanal had an MIC of 60,000 µg mL-1 for all Candida species, but fungicidal activity was only detected for Candida albicans (minimum fungicidal concentration: 60,000 µg mL-1). 1-Dodecanol (60,000 µg mL-1) exhibited fungistatic activity for C. albicans. Biofilm inhibition linked to an anti-adhesive effect of the oil and dodecanal was only detected for the standard S. aureus isolate and C. albicans, respectively. In conclusion, the essential oil from the inflorescence of E. elatior and its major components were more active against nonresistant strains S. aureus. Essential oil, dodecanol and dodecanal showed excellent activity against S. aureus, however, these same materials showed low activity against P. aeruginosa.

Species of the genus Myrciaria are widely used in Brazilian traditional medicine, including Myrciaria pilosa Sobral & Couto, whose leaves are employed to treat diarrhea, colic, edema, and stomach pain. Despite its popular use, scientific information regarding the chemical composition and toxicity of its leaf essential oil remains limited, highlighting the need for a systematic evaluation of its safety and pharmacological potential. This study aimed to characterize the chemical composition of Myrciaria pilosa leaf essential oil and evaluate its toxicity through in silico, in vitro, and in vivo approaches, including hematological, biochemical, and genotoxic endpoints. The essential oil was obtained by hydrodistillation and analyzed by gas chromatography coupled with mass spectrometry. In silico predictions were performed to assess affinity with human protein targets. Toxicity was assessed by in vitro hemolytic assay, acute oral toxicity (2000 mg/kg) and genotoxicity (comet and micronucleus assay) in mice. Chemical analysis identifying 39 compounds confirmed the predominance of β-eudesmol, elemol, and 5-epi-7-epi-α-eudesmol. In silico predictions indicated potential interactions with relevant human proteins, suggesting pharmacological activity. The oil exhibited low hemolytic activity (<10%) at all tested concentrations. In vivo, no behavioral changes, alterations in food intake, body weight, or hematological and biochemical parameters indicative of systemic toxicity were detected. A reduction in HDL, LDL, and total cholesterol levels suggested a hypolipidemic effect. Genotoxicity assays revealed no DNA damage or mutagenic activity. Myrciaria pilosa essential oil demonstrated a favorable safety profile at the tested dose, with no evidence of acute or genotoxic effects. These findings broaden the scientific knowledge regarding the species, support the importance of toxicological assessments of natural products, and highlight its potential for future therapeutic applications. Further studies are recommended to investigate safety under prolonged use.

Myrciaria floribunda is a plant found in the Northeast region of Brazil with several insecticidal properties that remain little explored. In this sense, this study aims to investigate the harmful effects of essential oil (EO) from M. floribunda leaves against Sitophilus zeamais, an important corn pest. The EO was applied in toxicity tests by fumigation, contact, and ingestion, as well as in in vitro assays to evaluate its effects on the activity of the enzymes α-amylase, trypsin, and acetylcholinesterase. Chromatographic analysis of the oil revealed (E)-caryophyllene (56.41%), viridiflorol (4.02%) and α-selinene (3.85%) as the main compounds. The essential oil (EO) showed fumigation toxicity, with an LC₅₀ of 3.2 μL/L of air, and (E)-caryophyllene with an LC₅₀ of 3.97 μL/L of air. The EO inhibited insect feeding, altering growth rate and feed conversion efficiency starting at 62.5 μL/g. In this study, an increase in amylase and acetylcholinesterase (AChE) activity was observed. This increase in AChE activity may cause an imbalance in the nervous system, leading to insect death. Thus, the EO of M. floribunda may serve as an alternative for the control of S. zeamais in stored corn and help prevent significant post-harvest losses for farmers.