In Vitro Evaluation of Anti-Rift Valley Fever Virus, Antioxidant and Anti-Inflammatory Activity of South African Medicinal Plant Extracts

• Published in: Viruses Vol. 13; no. 2; p. 221
• Main Authors: More, Garland K, Makola, Raymond T, Prinsloo, Gerhard
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31-01-2021; MDPI
• Subjects: Animals; Anti-inflammatory agents; Anti-Inflammatory Agents - chemistry; Anti-Inflammatory Agents - pharmacology; Antioxidants; Antioxidants - chemistry; Antioxidants - pharmacology; antiviral activity; Antiviral Agents - chemistry; Antiviral Agents - pharmacology; Cell culture; Chlorocebus aethiops; Coccidioidomycosis; Cytotoxicity; Drug Evaluation, Preclinical; Free radicals; H2DCF-DA; Herbal medicine; Herpes viruses; Inflammation; Medicinal plants; Oxidation; Plant extracts; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plants, Medicinal - chemistry; Reactive nitrogen species; Reactive oxygen species; Rift Valley fever; Rift Valley Fever - drug therapy; Rift Valley Fever - virology; rift valley fever virus; Rift Valley fever virus - drug effects; Rift Valley fever virus - growth & development; RTCA; South Africa; Tissue culture; Vero Cells; Viral infections; South Africa; Kenya; Africa; rift valley fever virus; H2DCF-DA; antiviral activity; medicinal plants; RTCA
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v13020221

Rift valley fever virus (RVFV) is a mosquito-borne virus endemic to sub-Saharan African countries, and the first sporadic outbreaks outside Africa were reported in the Asia-Pacific region. There are no approved therapeutic agents available for RVFV; however, finding an effective antiviral agent against RVFV is important. This study aimed to evaluate the antiviral, antioxidant and anti-inflammatory activity of medicinal plant extracts. Twenty medicinal plants were screened for their anti-RVFV activity using the cytopathic effect (CPE) reduction method. The cytotoxicity assessment of the extracts was done before antiviral screening using the MTT assay. Antioxidant and reactive oxygen/nitrogen species' (ROS/RNS) inhibitory activity by the extracts was investigated using non-cell-based and cell-based assays. Out of twenty plant extracts tested, eight showed significant potency against RVFV indicated by a decrease in tissue culture infectious dose (TCID
) < 10
. The cytotoxicity of extracts showed inhibitory concentrations values (IC
) > 200 µg/mL for most of the extracts. The antioxidant activity and anti-inflammatory results revealed that extracts scavenged free radicals exhibiting an IC
range of 4.12-20.41 µg/mL and suppressed the production of pro-inflammatory mediators by 60-80% in Vero cells. This study demonstrated the ability of the extracts to lower RVFV viral load and their potency to reduce free radicals.