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Anti-Mayaro virus activity of Cassia australis extracts (Fabaceae, Leguminosae)
Kassia C W Spindola1, Naomi K Simas2, Tiago S Salles3
1Natural Product Research Institute, Center of Health Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. kawaldhelm@gmail.com.
Background:
The arthropod-borne Mayaro virus (MAYV) causes 'Mayaro fever', a disease of medical significance, primarily affecting individuals in permanent contact with forested areas in tropical South America. Studies showed that the virus could also be transmitted by the mosquito Aedes aegypti. Recently, MAYV has attracted attention due to its likely urbanization. To date, there are no drugs that can treat this illness.
Methods:
Fractions and compounds were obtained by chromatography from leaf extracts of C. australis and chemically identified as flavonoids and condensed tannins using spectroscopic and spectrometric techniques (UV, NMR, and ESI-FT-ICR MS). Cytotoxicity of EtOAc, n-BuOH and EtOAc-Pp fractions were measured by the dye-uptake assay while their antiviral activity was evaluated by a virus yield inhibition assay. Larvicidal activity was measured by the procedures recommended by the WHO expert committee for determining acute toxicity.
Results:
The following group of substances was identified from EtOAc, n-BuOH and EtOAc-Pp fractions: flavones, flavonols, and their glycosides and condensed tannins. EtOAc and n-BuOH fractions inhibited MAYV production, respectively, by more than 70% and 85% at 25 μg/mL. EtOAc-Pp fraction inhibited MAYV production by more than 90% at 10 μg/mL, displaying a stronger antiviral effect than the licensed antiviral ribavirin. This fraction had an excellent antiviral effect (IC90 = 4.7 ± 0.3 μg/mL), while EtOAc and n-BuOH fractions were less active (IC90 = 89.1 ± 4.4 μg/mL and IC90 = 40.9 ± 5.7 μg/mL, respectively).
Conclusions:
C. australis can be used as a source of compounds with anti-Mayaro virus activity. This is the first report on the biological activity of C. australis.
Insights
Leaf extracts from C. australis show potent anti-Mayaro virus (MAYV) activity, offering a potential new treatment for Mayaro fever. This study highlights C. australis as a promising natural source for antiviral compounds.
Area of Science:
- Phytochemistry
- Virology
- Medical Entomology
Background:
- Mayaro virus (MAYV) causes Mayaro fever, a significant disease in tropical South America, with increasing urbanization concerns.
- Current treatment options for Mayaro fever are limited, necessitating the exploration of novel therapeutic agents.
- MAYV is transmitted by arthropods, including the Aedes aegypti mosquito.
Purpose of the Study:
- To investigate the potential of C. australis leaf extracts as a source of compounds with anti-Mayaro virus activity.
- To identify and characterize the active compounds present in C. australis extracts.
- To evaluate the efficacy of these compounds against MAYV in vitro.
Main Methods:
- Leaf extracts of C. australis were fractionated using chromatography.
- Compounds were identified using spectroscopic and spectrometric techniques (UV, NMR, ESI-FT-ICR MS).
- Antiviral activity was assessed via virus yield inhibition assays, with cytotoxicity evaluated by dye-uptake assays.
Main Results:
- Flavones, flavonols, glycosides, and condensed tannins were identified in the EtOAc, n-BuOH, and EtOAc-Pp fractions.
- The EtOAc-Pp fraction demonstrated significant inhibition of MAYV production (>90% at 10 μg/mL), outperforming the antiviral drug ribavirin.
- Potent antiviral effects were observed: IC90 values were 4.7 ± 0.3 μg/mL for EtOAc-Pp, 89.1 ± 4.4 μg/mL for EtOAc, and 40.9 ± 5.7 μg/mL for n-BuOH fractions.
Conclusions:
- C. australis serves as a valuable source of compounds exhibiting anti-Mayaro virus activity.
- This research marks the first report on the biological activities of C. australis.
- The identified compounds hold promise for the development of new treatments against Mayaro fever.
