Tigressa Helena Soares Rodrigues

Candida albicans is an opportunistic pathogen whose virulence factors, such as polymorphism and biofilm formation, facilitate infection. Due to rising antifungal resistance, essential oils (EOs) from Citrus limon and Citrus sinensis are being investigated for their antimicrobial potential. This study analyzes the chemical composition, antifungal activity against Candida albicans in planktonic and biofilm forms, cytotoxicity on human erythrocytes, and pharmacokinetic properties of Citrus limon and Citrus sinensis essential oils. The essential oils were extracted from the leaves by hydrodistillation, and their composition was analyzed by GC-MS. Antifungal activity was assessed using broth microdilution and time-kill kinetics. Combined effects were assessed using checkerboard assays, while antibiofilm tests were evaluated using polystyrene plate assays and microscopy. Hemolytic activity tests were performed using percentage hemolysis. C. limon essential oil had limonene 40.8%, β-pinene 16.5%, and citronellal 12.3%, while C. sinensis had limonene 36.7%, β-pinene 14.6%, and eucalyptol 10.5% as its main constituents. The MIC was 0.312 – 1.25 mg/mL, with kill kinetics of up to 10 h. It showed additive effects for C. limon/fluconazole and synergistic effects for C. sinensis/fluconazole. It exhibited anti-adhesion and anti-polymorphism effects, inhibiting biofilm formation. It also exhibited low cytotoxicity, with an LC₅₀ of 14 000 µg/mL for C. limon and 13 000 µg/mL for C. sinensis. ADMET and BOILED-egg pharmacokinetic predictions indicated safety for systemic use, with caution for topical application of limonene, citronellal, and eucalyptol. Both EOs exhibited strong anti-Candida activity with minimal cytotoxicity. Its additive/synergistic effects with fluconazole highlight its potential as an alternative or adjuvant therapy against C. albicans infections. Received: 17 August 2025 Accepted after revision: 03 February 2026 Article published online: 02 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 14, 70469 Stuttgart, Germany

Vitex gardneriana Schauer, known as “Jaramataia”, is widely used in folk medicine for its anti-inflammatory and analgesic properties. This study aimed to determine the chemical composition and evaluate the antifungal, antioxidant, and cytotoxic effects of the essential oil (EO) from its leaves. The EO was obtained via hydrodistillation and analyzed by GC-FID, identifying 16 components, with trans-calamenene (25.31%), 6,9-guaiadiene (18.33%), and caryophyllene oxide (15.14%) as major compounds. Antifungal activity was assessed by broth microdilution, showing a MIC of 5 mg/mL for all strains. A synergistic effect was observed when combined with amphotericin B, reducing the EO’s inhibitory concentration by over 30-fold. Antioxidant activity (DPPH method) showed an IC50 of 85.86 mg/mL, while hemolytic assays on human erythrocytes showed an IC50 of 20 mg/mL. Molecular docking revealed a stronger affinity of EO compounds to Sap5 (-7.3 kcal/mol) than Als3 (-6.2 kcal/mol), with some ligands (e.g., 1-epi-cubenol, caryophyllene oxide) binding to different regions than amphotericin B. These findings suggest that V. gardneriana EO has moderate antifungal activity. However, it shows promising potential when combined with conventional antifungal agents and supports future research toward the development of therapeutic formulations.

Background/Objectives: The incorporation of bioactive molecules into mesoporous carriers is a promising strategy to improve stability, solubility, and therapeutic efficacy. In this study, we report for the first time the encapsulation of the synthetic chalcone 4-Cl into KIT-6 mesoporous silica and evaluate its cytotoxicity, toxicological profile, and pharmacological activities (antinociceptive, anti-inflammatory, and anxiolytic) using an in vivo zebrafish (Danio rerio) model. Methods: Zebrafish were orally dosed with 4-Cl, 4-Cl/KIT-6, or KIT-6 (4, 20, 40 mg/kg) and mortality was recorded for 96 h. For analgesia, zebrafish pretreated with 4-Cl, 4-Cl/KIT-6, KIT-6, or morphine received a tail stimulus (0.1% formalin). Locomotor activity (quadrant crossings) was monitored for 30 min to assess analgesia (neurogenic: 0–5 min; inflammatory: 15–30 min). For inflammation, abdominal edema and weight gain were assessed 4 h after intraperitoneal carrageenan (1.5%). Zebrafish (n = 6/group) received 4-Cl, 4-Cl/KIT-6, or KIT-6 (4, 20, 40 mg/kg, p.o.). Controls received ibuprofen (100 mg/kg, p.o.) or 3% DMSO. Weight was measured hourly for 4 h post-carrageenan (difference between baseline and hourly weights). Results: Physicochemical characterizations confirmed successful encapsulation without compromising the ordered structure of KIT-6, as evidenced by a significant reduction in surface area and pore volume, indicating efficient drug incorporation. In vivo assays demonstrated that the 4-Cl/KIT-6 formulation maintained the pharmacological activities of the free chalcone, reduced toxicity, and, notably, revealed a significant anxiolytic effect for the first time. Conclusions: These findings highlight KIT-6 as a promising platform for chalcone delivery systems and provide a solid basis for future preclinical investigations.

This study investigated the biosynthesis of ethyl oleate (EO), the main constituent of biodiesel, via the esterification of oleic acid with ethanol, catalyzed by Candida antarctica lipase B (CALB) immobilized on a low‐cost support derived from cashew apple bagasse (CAB) lignin. Cashew apple bagasse lignin extraction was carried out through an acid‐alkali process and used to produce the CAB‐lignin conjugated with magnetite (Lig‐MNP) composite, which served as the support for enzyme immobilization. The biocatalyst (Lig‐MNP/CALB), obtained through the immobilization process, exhibited an activity of 13 U g⁻¹ and was subsequently applied in esterification reactions to evaluate its catalytic efficiency in comparison to the free enzyme. Acid‐to‐alcohol molar ratio, temperature, and catalytic load were evaluated. Under optimal conditions – 40 mg mL⁻¹ catalyst load, 40 °C, and a 1:2 molar ratio – Lig‐MNP/CALB achieved a maximum EO conversion of 90%. The immobilized enzyme demonstrated operational stability over multiple cycles and was easily recovered through magnetic separation. The purified biofuel reached approximately 90% purity in ethyl oleate and 98% in total esters content. These results highlight the potential of the biocatalyst for sustainable biofuel production.

A resistência bacteriana representa um desafio global à saúde pública, demandando a busca por alternativas terapêuticas eficazes. Neste contexto, este estudo investigou a composição química e a atividade antimicrobiana do óleo essencial de Alpinia zerumbet (OEAZ) contra Staphylococcus aureus e Staphylococcus epidermidis. O óleo foi extraído das folhas da planta por hidrodestilação utilizando um aparelho de Clevenger, apresentando rendimento de 0,19% p/p. A análise por cromatografia gasosa acoplada a espectrômetro de massas (GCMS) identificou 14 compostos, sendo o Terpineno-4-ol (27,68%) o composto majoritário, seguido por Eucaliptol (24,08%), Sabineno(11,99%) e γ-Terpineno (11,33%). A atividade antimicrobiana foi avaliada pelos métodos de disco-difusão, determinação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM). O OEAZ apresentou zona de inibição de 28 mm para ambas as cepas testadas, com CIM de 5.000 μg/mL para S. aureus e 10.000 μg/mL para S. epidermidis. Apesar da atividade antimicrobiana evidenciada, os valores elevados de CIM e CBM indicam a necessidade de estratégias para otimizar sua eficácia, como combinações terapêuticas ou encapsulamento. Os resultados reforçam o potencial do OEAZ como um agente antimicrobiano natural, embora estudos adicionais sejam necessários para validar sua aplicação clínica, investigar sua toxicidade e explorar sua eficácia contra microrganismos multirresistentes. Este trabalho contribui para o desenvolvimento de novas abordagens terapêuticas frente à crescente resistência bacteriana.

The Aedes aegypti mosquito is the primary vector of dengue, a neglected disease and a serious public health problem in tropical countries. The control of this vector has been carried out using chemical insecticides, which impact human health. Thus, it is essential to develop natural larvicides that are less harmful to the environment. This study investigates the circadian cycle and larvicidal activity of essential oils from Croton blanchetianus against Aedes aegypti. The leaf oils were extracted by hydrodistillation and analyzed by GC–MS and GC–FID. The circadian study revealed variations in the chemical composition of oils extracted at different times of the day. The main constituents were α-pinene, β-phellandrene, eucalyptol, β-caryophyllene, bicyclogermacrene, and spathulenol. The larvicidal activity showed LC₅₀ values at the following different collection times: 55.294 ± 3.209 μg/mL at 08:00 h; 95.485 ± 2.684 μg/mL at 12:00 h; and 64.883 ± 1.780 μg/mL at 17:00 h. Molecular docking simulations indicated that α-pinene, β-phellandrene, eucalyptol, and β-caryophyllene strongly interact with the active site of the sterol carrier protein, suggesting their role in larvicidal activity. These findings reinforce the potential of C. blanchetianus essential oils as an alternative for Aedes aegypti control. The predictive pharmacokinetic tests showed a PAMPA profile associated with high effective cellular permeability and microsomal stability, resulting from the metabolic stability of the derivatives (3) eucalyptol and (6) spathulenol, indicating that these compounds have the highest pharmacokinetic viability and low reactivity with respect to organ toxicity.

Objectives: Malaria continues to be the primary cause of mortality worldwide, and timely recognition and prompt intervention are crucial in mitigating adverse consequences. This review article aims to examine the effectiveness and structural characteristics of quinoline-based compounds as antimalarial agents. It specifically focuses on their therapeutic effects as well as potential prospects for exploring structure-activity relationship (SAR). In addition, this study aims to identify lead compounds that can efficiently battle multidrug-resistant forms of Plasmodium falciparum and Plasmodium vivax. Methods: A comprehensive review was conducted to evaluate the effectiveness of quinoline-based antimalarial medications in eradicating P. falciparum and P. vivax. The mechanism of action and SAR of these compounds were analyzed Results: Quinoline-based antimalarials demonstrated significant effectiveness in eliminating P. falciparum parasites, particularly in regions severely impacted by malaria, including Africa and Asia. These compounds were found to exhibit tolerance and immune-modulating properties, indicating their potential for more widespread utilization. The investigation identified various new quinoline compounds with improved antimalarial activity, including metal-chloroquine complexes, diaminealkyne chloroquines, and cinnamoylated chloroquine hybrids. This study explored different mechanisms by which these compounds interact with parasites, including their ability to accumulate in the parasite’s acidic food vacuoles and disrupt heme detoxification. The derivatives demonstrated strong efficacy against chloroquine-resistant strains and yielded positive results. Conclusion: Quinoline-based compounds represent a promising avenue for combating malaria due to their demonstrated efficacy against P. falciparum and P. vivax parasites. Further research on their mechanisms of action and SAR could lead to the development of more effective antimalarial medications.