Abstract
The coronavirus disease 2019 (COVID-19) has become a serious problem for public health since it was identified in the province of Wuhan (China) and spread around the world producing high mortality rates and economic losses. Nowadays, the WHO recognizes traditional, complementary, and alternative medicine for treating COVID-19 symptoms. Therefore, we investigated the antiviral potential of the hydroalcoholic extract of Uncaria tomentosa stem bark from Peru against SARS-CoV-2 in vitro. The antiviral activity of U. tomentosa against SARS-CoV-2 in vitro was assessed in Vero E6 cells using cytopathic effect (CPE) and plaque reduction assay. After 48 h of treatment, U. tomentosa showed an inhibition of 92.7% of SARS-CoV-2 at 25.0 μg/mL (p < 0.0001) by plaque reduction assay on Vero E6 cells. In addition, U. tomentosa induced a reduction of 98.6% (p=0.02) and 92.7% (p=0.03) in the CPE caused by SARS-CoV-2 on Vero E6 cells at 25 μg/mL and 12.5 μg/mL, respectively. The EC50 calculated for the U. tomentosa extract by plaque reduction assay was 6.6 μg/mL (4.89–8.85 μg/mL) for a selectivity index of 4.1. The EC50 calculated for the U. tomentosa extract by TCID50 assay was 2.57 μg/mL (1.05–3.75 μg/mL) for a selectivity index of 10.54. These results showed that U. tomentosa, known as cat's claw, has an antiviral effect against SARS-CoV-2, which was observed as a reduction in the viral titer and CPE after 48 h of treatment on Vero E6 cells. Therefore, we hypothesized that U. tomentosa stem bark could be promising in the development of new therapeutic strategies against SARS-CoV-2.
Highlights
The World Health Organization (WHO) recognizes traditional, complementary, and alternative medicine for treating COVID-19 symptoms. erefore, we investigated the antiviral potential of the hydroalcoholic extract of Uncaria tomentosa stem bark from Peru against SARSCoV-2 in vitro. e antiviral activity of U. tomentosa against SARS-CoV-2 in vitro was assessed in Vero E6 cells using cytopathic effect (CPE) and plaque reduction assay
Different constituents in the U. tomentosa stem bark such as spirooxindole alkaloids, indole glycoside alkaloids, quinovic acid glycosides, and proanthocyanidins were identified by LC-MS analysis (Table 1 and Supplementary materialsS1–S6). e LC-MS data provided information on spirooxindole alkaloids as a broad peak that appeared at a retention time of 4.82 min and showed an (M + H) + ion at m/z 369.18018 that are characteristics for speciophylline, isopteropodine, isomitraphylline, uncarine F, mitraphylline, and pteropodine
LC/MS phytochemical analysis showed that the hydroalcoholic extract of U. tomentosa was comprised predominantly of five proanthocyanidins (PAs), including proanthocyanidin C1, epiafzelechin-4β-8, proanthocyanidin B2, epicatechin, and chlorogenic acid, which eluted at 3.76–4.25 min
Summary
Zapata-Cardona ,4 Lina Yepes ,4 Wbeimar Aguilar-Jimenez ,4 Marıa T. E antiviral activity of U. tomentosa against SARS-CoV-2 in vitro was assessed in Vero E6 cells using cytopathic effect (CPE) and plaque reduction assay. After 48 h of treatment, U. tomentosa showed an inhibition of 92.7% of SARS-CoV-2 at 25.0 μg/mL (p < 0.0001) by plaque reduction assay on Vero E6 cells. Ese results showed that U. tomentosa, known as cat’s claw, has an antiviral effect against SARS-CoV-2, which was observed as a reduction in the viral titer and CPE after 48 h of treatment on Vero E6 cells. Evidence-Based Complementary and Alternative Medicine with COVID-19 whereas Venezuela and Uruguay were the ultimate nations to confirm their patient zero, considering the pandemic epicenter after Europe [4]. Even though some vaccines have already been approved only with phase 3 results, currently, there is no preventive treatment or antiviral drug available against SARS-CoV-2 [5]
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