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Background: Tontelea micrantha , a notable plant species, has garnered interest for its medicinal properties, including anti-inflammatory, antibacterial and antiviral effects. A vaccine for Chikungunia virus is still under evaluation and no specific antiviral drug has been licensed to date., Objective: The work investigated antiviral activity of ethyl acetate (EAEF) and methanolic (EMF) extracts from T. micrantha leaves in mammalian cells exposed to Alphavirus chikungunya (CHIKV). This plant species showed remarkable medicinal properties including anti-inflammatory, antiviral and antibacterial effects., Methods: The cytotoxicity, antiviral activity, selectivity index, effect on viral gene expression, virus production, and mechanisms of action were evaluated., Results: EAEF and EMF extracts showed anti-CHIKV effects at non-cytotoxic concentrations, with CC 50 above 300μg/mL, EC 50 of 18 and 43 μg/mL respectively, and selectivity Index above 4. These concentrations drastically reduce viral yields and CHIKV gene expression and have shown activity both directly on viral particles and at different stages of the viral cycle., Conclusion: EAEF and EMF showed robust antiviral activity against CHIKV, making them promising candidates for the development of anti-CHIKV drugs.

The pharmacological properties of plant extracts and phytochemicals, such as flavonoids and terpenoids, remain of great interest. In this work, the effect of extracts, friedelan-3,21-dione, and 3β- O -D-glucosyl-sitosterol isolated from Tontelea micrantha roots was evaluated against Staphylococcus aureus , Bacillus subtilis , Klebsiella pneumoniae , Klebsiella oxytoca and Escherichia coli . The antibacterial activity was evaluated by the minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively), and the synergistic effect was assessed by the Checkerboard assay. Furthermore, the cytotoxicity of the plant-derived compounds against Vero cells was measured by the 3-(4 5-dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide (MTT) method. The biological effects of the isolated compounds were predicted using the PASS online software. The chloroform and hexane extracts of T. micrantha roots showed promising antibacterial effect, with MIC in the range of 4.8-78.0 µg/mL. Further analyses showed that these compounds do not affect the integrity of the membrane. The combination with streptomycin strongly reduced the MIC of this antibiotic and extracts. The extracts were highly toxic to Vero cells, and no cytotoxicity was detected for the two terpenoids isolated from them (i.e. friedelan-3,21-dione and 3β- O -D-glucosyl-sitosterol; CC 50  > 1000 μg/mL). Therefore, extracts obtained from T. micrantha roots significantly inhibited bacterial growth and are considered promising agents against pathogenic bacteria. The cytotoxicity results were very relevant and can be tested in bioassays.

Oropouche virus (OROV) is the aetiological agent of Oropouche fever, the symptoms of which are common to most arboviruses, such as fever, headache, malaise, nausea and vomiting. More than half a million people have been infected with OROV since its isolation in 1955. Although Oropouche fever is classified as a neglected and emerging disease, to date, there are no antiviral drugs or vaccines available against the infection and little is known about its pathogenicity. Therefore, it is essential to elucidate the possible mechanisms involved in its pathogenesis. Since oxidative stress plays a pivotal role in the progression of various viral diseases, in this study, redox homeostasis in the target organs of OROV infection was evaluated using an animal model. Infected BALB/c mice exhibited reduced weight gain, splenomegaly, leukopenia, thrombocytopenia, anaemia, development of anti-OROV neutralizing antibodies, increased liver transaminases, and serum levels of pro-inflammatory cytokines tumour necrosis factor (TNF-α) and interferon-γ (IFN-γ). The OROV genome and infectious particles were detected in the liver and spleen of infected animals, with liver inflammation and an increase in the number and total area of lymphoid nodules in the spleen. In relation to redox homeostasis in the liver and spleen, infection led to an increase in reactive oxygen species (ROS) levels, increased oxidative stress biomarkers malondialdehyde (MDA) and carbonyl protein, and decreased activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Taken together, these results help elucidate some important aspects of OROV infection that may contribute to the pathogenesis of Oropouche.