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ETHNOPHARMACOLOGICAL RELEVANCE: The terrestrial stems of Ephedra (Ephedra spp.; including Ephedra sinica Stapf and Ephedra przewalskii Stapf) extracts are used in traditional medicines in East Asia. In Japan, the Kampo formula containing E. sinica extract is prescribed for the treatment of the common cold, influenza virus infections, and mild symptoms of coronavirus disease 2019 (COVID-19). Although ephedrine alkaloids in E. sinica exert antitussive effects, they may have side effects associated with the sympathetic nervous system. E. przewalskii extract, a drug used in traditional Uyghur and Mongolian medicine, is considered to be free of ephedrine alkaloids and is a promising candidate for the treatment of infectious diseases. However, its use is currently limited because evidence of its antiviral efficacy remains inconclusive. AIM OF THE STUDY: We compared the anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) effects of E. przewalskii and E. sinica extracts in vitro. Additionally, we examined the differences in their antiviral effects against different SARS-CoV-2 strains. MATERIALS AND METHODS: VeroE6/TMPRSS2 cells were infected with SARS-CoV-2 (Conventional, Delta, and Omicron strains-BA.1, BA.2, BA.4, and BA.5), and lysates prepared from each herbal extract were added. The infectious titer was determined using the 50% tissue culture infectious dose (TCID50) method; in turn, the half-maximal inhibitory concentration (IC50) was calculated for each extract to compare the antiviral efficacy of E. sinica and E. przewalskii extracts. Further, the extracts were compared with remdesivir for their antiviral efficacy against the conventional viral strain. To verify the effect of the inactivation of virus particles, these extracts were added to each SARS-CoV-2 strain, and the infectious titers were determined using the TCID50 method. RESULTS: The antiviral efficacy (i.e., IC50) of the E. przewalskii extract against each SARS-CoV-2 strain was 2.7-10.8-fold greater than that of the E. sinica extract. The antiviral efficacy of the E. przewalskii extract against conventional viral strains was compared with that of remdesivir, which was 1/27.6 of remdesivir's efficacy. The E. sinica extract showed minimal inactivation of virus particles of each strain, whereas the E. przewalskii extract resulted in substantial viral inactivation. CONCLUSIONS: The E. przewalskii extract showed higher antiviral activity against SARS-CoV-2 than the E. sinica extract. Overall, our study suggests that E. przewalskii extract can be used for the treatment of viral infections, including COVID-19.
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Alcaloides , COVID-19 , Ephedra sinica , Ephedra , SARS-CoV-2 , Efedrina , Antivirales/farmacología , Antivirales/uso terapéutico , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéuticoRESUMEN
Chlorous acid water (HClO2) is known for its antimicrobial activity. In this study, we attempted to accurately assess the ability of chlorous acid water to inactivate SARS-CoV-2. When using cell culture supernatants of infected cells as the test virus, the 99% inactivation concentration (IC99) for the SARS-CoV-2 D614G variant, as well as the Delta and Omicron variants, was approximately 10ppm of free chlorine concentration with a reaction time of 10 minutes. On the other hand, in experiments using a more purified virus, the IC99 of chlorous acid water was 0.41-0.74ppm with a reaction time of 1 minute, showing a strong inactivation capacity over 200 times. With sodium hypochlorite water, the IC99 was 0.54ppm, confirming that these chlorine compounds have a potent inactivation effect against SARS-CoV-2. However, it became clear that when using cell culture supernatants of infected cells as the test virus, the effect is masked by impurities such as amino acids contained therein. Also, when proteins (0.5% polypeptone, or 0.3% BSA + 0.3% sheep red blood cells, or 5% FBS) were added to the purified virus, the IC99 values became high, ranging from 5.3 to 76ppm with a reaction time of 10 minutes, significantly reducing the effect. However, considering that the usual usage concentration is 200ppm, it was shown that chlorous acid water can still exert sufficient disinfection effects even in the presence of proteins. Further research is needed to confirm the practical applications and effects of chlorous acid water, but it has the potential to be an important tool for preventing the spread of SARS-CoV-2.
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COVID-19 , Desinfectantes , Virus , Animales , Humanos , Ovinos , Desinfectantes/farmacología , SARS-CoV-2 , Cloro/farmacología , AguaRESUMEN
We first investigated the interactions between several algae-derived lectins and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We created lectin columns using high-mannose (HM)-type glycan-specific lectins OAA and KAA-1 or core fucose-specific lectin hypninA-2 and conducted binding experiments with SARS-CoV-2. The results showed that these lectins were capable of binding to the virus. Furthermore, when examining the neutralization ability of nine different lectins, it was found that KAA-1, ESA-2, and hypninA-2 were effective in neutralizing SARS-CoV-2. In competitive inhibition experiments with glycoproteins, neutralization was confirmed to occur through HM-type or core fucose-type glycans. However, neutralization was not observed with other lectins, such as OAA. This trend of KAA-1 and ESA-2 having the neutralizing ability and OAA not having it was also similar to influenza viruses. Electron microscopy observations revealed that KAA-1 and hypninA-2 strongly aggregated SARS-CoV-2 particles, while OAA showed a low degree of aggregation. It is believed that the neutralization of SARS-CoV-2 involves multiple factors, such as glycan attachment sites on the S protein, the size of lectins, and their propensity to aggregate, which cause inhibition of receptor binding or aggregation of virus particles. This study demonstrated that several algae-derived lectins could neutralize SARS-CoV-2 and that lectin columns can effectively recover and concentrate the virus.
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COVID-19 , Orthomyxoviridae , Humanos , SARS-CoV-2/metabolismo , Manosa/metabolismo , Fucosa , Lectinas/farmacología , Lectinas de Unión a Manosa/metabolismo , Lectinas de Unión a Manosa/farmacología , Polisacáridos/metabolismoRESUMEN
OBJECTIVES: This study assessed the concentration of SARS-CoV-2 in the air of hospital rooms occupied by patients with COVID-19 who had viable SARS-CoV-2 in nasopharyngeal (NP) samples in early infection. METHODS: Between July and October 2021, NP swabs were collected from 20 patients with early SARS-CoV-2 infection admitted to a tertiary hospital in Japan. Air samples were collected from their rooms, tested for SARS-CoV-2 RNA, and cultured to determine potential infectivity. RESULTS: The NP swab samples of 18 patients were positive for viable SARS-CoV-2 (median concentration: 4.0 × 105 tissue culture infectious dose 50/ml). In the air samples, viral RNA (median concentration: 1.1 × 105 copies/m3) was detected in 12/18 (67%) patients, and viable virus (median concentration: 8.9 × 102 tissue culture infectious dose 50/m3) was detected in 5/18 (28%) patients. The median time between illness onset and sampling was 3 days. The RNA concentration was significantly higher in samples wherein viable SARS-CoV-2 was detected than in samples in which viable virus was not detected (P-value = 0.027). CONCLUSION: Viable SARS-CoV-2 can be detected in the air surrounding patients with early SARS-CoV-2 infection. Health care workers should pay attention to infection control when caring for patients with early SARS-CoV-2 infection.
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COVID-19 , Humanos , COVID-19/diagnóstico , SARS-CoV-2/genética , ARN Viral/genética , Hospitales , HospitalizaciónRESUMEN
INTRODUCTION: New treatment methods, such as REGN-CoV2, have been approved for patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the effect of the drug on the duration of infectious viral shedding and viral mutations is unknown. In this study, we investigated the clinical efficacy of REGN-CoV2 treatment in patients with mild to moderate disease and compared its antiviral effects against different strains of SARS-CoV-2. METHODS: Viral culture and PCR testing were performed on the pharyngeal swabs collected from 28 patients with COVID-19 who were admitted and treated at Hiroshima University Hospital during the study period. Of these, 23 patients were treated with REGN-CoV2. The patients were classified into the REGN-CoV2(+) and REGN-CoV2(-) groups, and the clinical course was compared between the groups. The 50% inhibitory concentrations (IC50) of REGN-CoV2 against the isolated virus strains were determined. RESULTS: After treatment with REGN-CoV2, the virus culture positivity rate was greatly reduced. The time to negative viral culture was significantly shorter in the REGN-CoV2(+) group than in the REGN-CoV2(-) group. In vitro evaluation of REGN-CoV2 against isolated virus strains also showed efficacy. CONCLUSIONS: REGN-CoV2 treatment was effective in patients with mild COVID-19 and could shorten the period of infectious viral shedding. This may be an important factor in preventing the spread of infection. It may be possible to revise the isolation period for patients with mild disease treated with REGN-CoV2.
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Tratamiento Farmacológico de COVID-19 , SARS-CoV-2 , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Neutralizantes , Combinación de Medicamentos , Humanos , ARN Viral , Esparcimiento de VirusRESUMEN
Several traditional Japanese Kampo formulas are known to have inhibitory effects on infections with viruses that cause respiratory symptoms. Although some herbs and their components have been reported to suppress SARS-CoV-2 replication in vitro, it is difficult to compare effective Kampo formulas because of the different methods used in studies. Thus, we carried out in vitro experiments on the suppression of SARS-CoV-2 infection by Kampo formulas and crude drugs used for the common cold to compare their suppressive effects on virus infection. After infecting VeroE6/TMPRSS2 cells with SARS-CoV-2, lysates of the Kampo formulas and crude drugs were added, and after 24 h, the infectious titer in the medium was measured by the TCID50 method. Maoto was the most effective among the Kampo formulas, and Ephedrae herba was the most effective among the constituent crude drugs. However, a comparison of the suppressive effects of Ephedrae herba and Kampo formulas containing Ephedrae herba showed that the suppressive effect on virus infection did not depend on the content of Ephedrae herba. Based on the results, we believe that the use of Maoto among Kampo formulas is suitable as a countermeasure against COVID-19.
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BACKGROUND: Approximately 5% of patients with coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 develop severe COVID-19. Severe COVID-19 requires respiratory management with mechanical ventilation and an extended period of treatment. Prolonged infectious virus shedding is a concern in severe COVID-19 cases, but few reports have examined the duration of infectious virus shedding. Therefore, we investigated the duration of infectious virus shedding in patients transferred to Hiroshima University Hospital with severe COVID-19 requiring mechanical ventilation. METHODS: Nasopharyngeal swab specimens were collected and analyzed using both viral culture and reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) tests between December 2020 and February 2021. RESULTS: Of the 23 patients tested, the proportions of those with positive test results at first specimen collection (the median number of days to first specimen collection after symptom onset was 10) on RT-qPCR and viral culture tests were 95·7% and 30·4%, respectively. All six patients with positive viral culture test results who were followed-up tested negative 24 days after symptom onset but remained positive on RT-qPCR. Viral loads based on PCR testing did not decrease over time, but those determined via culture tests decreased over time. The longest negative conversion time was observed in a dialysis patient on immunosuppressive drugs. CONCLUSIONS: This study indicated that patients with severe COVID-19 remain culture positive for ≥ 10 days after symptom onset. Additionally, immunosuppressed patients with severe COVID-19 could consider isolation for ≥ 20 days.
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COVID-19 , Humanos , ARN Viral/genética , Respiración Artificial , SARS-CoV-2 , Carga Viral , Esparcimiento de VirusRESUMEN
Ethanol is an effective disinfectant against the novel coronavirus SARS-CoV-2. However, its effective concentration has not been shown, and we therefore analyzed the effects of different concentrations of ethanol on SARS-CoV-2. When SARS-CoV-2 was treated with varying ethanol concentrations and examined for changes in infectivity, the ethanol concentration at which 99% of the infectious titers were reduced was 24.1% (w/w) [29.3% (v/v)]. For reference, ethanol susceptibility was also examined with other envelope viruses, including influenza virus, vesicular stomatitis virus in the family Rhabdoviridae, and Newcastle disease virus in the family Paramyxoviridae, and the 99% inhibitory concentrations were found to be 28.8%(w/w) [34.8% (v/v)], 24.0% (w/w) [29.2% (v/v)], and 13.3% (w/w) [16.4% (v/v)], respectively. Some differences from SARS-CoV-2 were observed, but the differences were not significant. It was concluded that ethanol at a concentration of 30%(w/w) [36.2% (v/v)] almost completely inactivates SARS-CoV-2.
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Desinfectantes/farmacología , Etanol/farmacología , SARS-CoV-2/efectos de los fármacos , COVID-19/virología , Desinfectantes/análisis , Etanol/análisis , Humanos , SARS-CoV-2/crecimiento & desarrollo , SARS-CoV-2/fisiología , Inactivación de Virus/efectos de los fármacos , Virus/efectos de los fármacos , Virus/crecimiento & desarrolloRESUMEN
Since understanding molecular mechanisms of SARS-CoV-2 infection is extremely important for developing effective therapies against COVID-19, we focused on the internalization mechanism of SARS-CoV-2 via ACE2. Although cigarette smoke is generally believed to be harmful to the pathogenesis of COVID-19, cigarette smoke extract (CSE) treatments were surprisingly found to suppress the expression of ACE2 in HepG2 cells. We thus tried to clarify the mechanism of CSE effects on expression of ACE2 in mammalian cells. Because RNA-seq analysis suggested that suppressive effects on ACE2 might be inversely correlated with induction of the genes regulated by aryl hydrocarbon receptor (AHR), the AHR agonists 6-formylindolo(3,2-b)carbazole (FICZ) and omeprazole (OMP) were tested to assess whether those treatments affected ACE2 expression. Both FICZ and OMP clearly suppressed ACE2 expression in a dose-dependent manner along with inducing CYP1A1. Knock-down experiments indicated a reduction of ACE2 by FICZ treatment in an AHR-dependent manner. Finally, treatments of AHR agonists inhibited SARS-CoV-2 infection into Vero E6 cells as determined with immunoblotting analyses detecting SARS-CoV-2 specific nucleocapsid protein. We here demonstrate that treatment with AHR agonists, including CSE, FICZ, and OMP, decreases expression of ACE2 via AHR activation, resulting in suppression of SARS-CoV-2 infection in mammalian cells.
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BACKGROUND: The effectiveness of 222 nm ultraviolet (UV) C light for disinfecting surfaces contaminated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported. The aim of this study was to evaluate the effect of the intermittent irradiation of 222 nm UVC on SARS-CoV-2 and the fluence-dependent effect of 222 nm UVC irradiation on SARS-CoV-2 inactivation. METHODS: We experimented with 5 min continuous and intermittent irradiation for 0.1, 0.05, 0.013, and 0.003 mW/cm2 of 222 nm UVC to evaluate the differences in the effect of the continuous and intermittent irradiation of 222 nm UVC on SARS-CoV-2 inactivation. For intermittent irradiation, we followed the on-off irradiation cycles with every 10-s irradiation followed by a 380-s interval. Thereafter, we evaluated the effects of 0.1, 0.013, and 0.003 mW/cm2 222 nm UVC irradiation on SARS-CoV-2 contamination at UV fluences of 1, 2, and 3 mJ/cm2 at each irradiance. RESULTS: At each irradiance, no significant difference was observed in the log reduction of SARS-CoV-2 between continuous and intermittent irradiation. At each UV fluence, no significant difference was observed in the log reduction of SARS-CoV-2 among the three different irradiance levels. CONCLUSION: There was no significant difference between continuous and intermittent irradiation with 222 nm UVC with regards to SARS-CoV-2 inactivation. Moreover, 222 nm UVC inactivates SARS-CoV-2 in a fluence-dependent manner. The efficacy of 222-nm UVC irradiation in reducing the contamination of SARS-CoV-2 needs to be further evaluated in a real-world setting.
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Desinfección/métodos , SARS-CoV-2/efectos de la radiación , Rayos Ultravioleta , Humanos , Inactivación de VirusRESUMEN
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has emerged as a serious threat to human health worldwide. Efficient disinfection of surfaces contaminated with SARS-CoV-2 may help prevent its spread. This study aimed to investigate the in vitro efficacy of 222-nm far-ultraviolet light (UVC) on the disinfection of SARS-CoV-2 surface contamination. METHODS: We investigated the titer of SARS-CoV-2 after UV irradiation (0.1 mW/cm2) at 222 nm for 10-300 seconds using the 50% tissue culture infectious dose (TCID50). In addition, we used quantitative reverse transcription polymerase chain reaction to quantify SARS-CoV-2 RNA under the same conditions. RESULTS: One and 3 mJ/cm2 of 222-nm UVC irradiation (0.1 mW/cm2 for 10 and 30 seconds) resulted in 88.5 and 99.7% reduction of viable SARS-CoV-2 based on the TCID50 assay, respectively. In contrast, the copy number of SARS-CoV-2 RNA did not change after UVC irradiation even after a 5-minute irradiation. CONCLUSIONS: This study shows the efficacy of 222-nm UVC irradiation against SARS-CoV-2 contamination in an in vitro experiment. Further evaluation of the safety and efficacy of 222-nm UVC irradiation in reducing the contamination of real-world surfaces and the potential transmission of SARS-CoV-2 is needed.