Study 1

Kuti , D. et al.: Antiviral Effect of Traditional Medicinal Plant Extracts Against Seasonal Influenza Viruses and Sars Coronavirus-2 In Cell Culture

Published in Journal of Community Medicine and Public Health Reports

The winter season is marked by a higher occurrence of viral illnesses across the population. Starting from the 2022/2023 season, there is a strong likelihood that in the coming years, we will encounter a concurrent presence of influenza viruses and type 2 coronavirus, potentially leading to significant health implications for the population. As a result, treatment options capable of effectively combatting both viral infections will hold a critical role in both treatment and prevention.

Aim of the Study

A team of scientists led by Dr. Dávid Kuti from Budapest, Hungary conducted an in vitro clinical study on cell cultures. The aim of the study was to determine the inhibitory effect of extracts from selected medicinal plants on the replication of influenza virus strains (type B virus, type A H2N2, and H1N1 viruses) and the SARS-CoV-2 virus.

The effects of the following extracts, both individually and in combination (VIROSTOP Mixtura), were observed: 

  • Cistus creticus eriocephalus extract
  • Echinaceae purpureae extract
  • Salvia officinalis extract
  • Citrus bioflavonoid complex
  • Acerola dried extract
  • Virostop mixture – a combination of all the mentioned extracts

Tests were conducted on cell cultures as follows:

  • In the case of influenza virus strains, virus neutralization took place on MDCK cell cultures (Madin-Darby Canine Kidney cells - cell culture derived from the kidney cells of a Cocker Spaniel).
  • For the SARS-CoV-2 virus, propagation was carried out using Vero E6 cells (cell culture derived from the kidney cells of an African green monkey).


Inhibitory effects of the compounds against Influenza and Sars-Cov-2 viruses relative to the effect of Cistus creticus

The study demonstrated that the combined effect of all extracts together in Mixtura VIROSTOP exhibits up to twice the effectiveness compared to individual extracts alone, both against influenza virus strains and the SARS-CoV-2 virus.
We can conclude that the effects of medicinal plant extracts are mutually enhanced in the mixture, resulting in a stronger antiviral effect.

Study 2

Jankovics , I. et al.: Early use of polyphenol-rich Cistus creticus extract containing nasopharyngeal spray is associated with significantly shorter duration of symptoms in mild COVID-19 patients: A retrospective case- control study

Published on September 30, 2021
in Journal Of Community Medicine and Public Health Reports (ISSN: 2692-9899)

Aim of the study

To verify the clinical effect of VIROSTOP nasopharyngeal spray containing Cistus extract creticus in mild COVID-19

Composition: Cistus creticus Acrocephalus extra., 100 mg/ml; Echinacea purpureae extra., 240 mg/ml; Salvia officinalis extra., 45 mg/ml; Citrus bioflavonoid complex, 20 mg/ml; Acerola dried ext. 120 mg/ml

Study Design

A single-center , retrospective, controlled study based on the results of filling out the validated standardized questionnaire Wisconsin Upper Respirators Symptom Survey (WURSS-24). The WHO Upper Respiratory Tract Infection Score and Severity and Interference Score were also assessed.

170 patients with PCR-confirmed SARS-CoV-2 infection were enrolled, of which 86 patients in the observation group (CCE, standard treatment in combination with VIROSTOP nasopharyngeal spray) and 84 patients in the control group (CONTROL, only standard treatment).

  • The primary outcome was monitoring of changes in symptoms on day 12 of clinical follow-up.
  • The secondary outcome was the rate of PCR positivity from the nasopharyngeal swab at 10-15. day of treatment.

The inclusion condition was that these patients had symptoms no earlier than 96 hours before seeking medical help.

At the beginning of the study, the differences in the incidence of symptoms between the groups were statistically insignificant, with the exception of headache and fatigue, which were more frequently reported in the study group.

Clinical study results

PCR negativity of the presence of the SARS-CoV-2 virus in the control and monitored groups on the 12th day of treatment

At the end of the study, there was a significant improvement in symptoms in the monitored group compared to the control group, namely:

  • In case of nausea on the 10th day,
  • In case of headache, nasal congestion and sore throat on the 12th day.

On the 12th day of treatment, 19.05% of patients from the control group (CONTROL) and only 6.98% from the observation group (CCE) were still PCR positive.

Use of VIROSTOP nasopharyngeal spray containing Cistus extract creticus significantly contributed to a more significant reduction in the occurrence of disease symptoms, as well as to a faster elimination of SARS-CoV-2 viruses from the respiratory tract during a mild course of COVID-19.

Study 3

Jankovics , I. et al.: Using polyphenol rich Cistus creticus and other plant extracts containing nasopharyngeal spray may provide an additional tool in the preventive and symptomatic armamentarium against mild upper respiratory tract infections

Published on November 14, 2022
in Journal Of Community Medicine And Public Health Reports (ISSN: 2692:9899)

Aim of the study

Cistus creticus extract in combination with other plant extracts in the form of VIROSTOP nasopharyngeal spray in disease prevention and and alleviating symptoms in patients.

Composition: Cistus creticus Acrocephalus extra., 100 mg/ml; Echinacea purpureae extra., 240 mg/ml; Salvia officinalis extra., 45 mg/ml; Citrus bioflavonoid complex, 20 mg/ml; Acerola dried ext. 120 mg/ml.

Study design

A single-center , retrospective, controlled study that took place between February and May 2021

Patients who were close contacts of people with PCR-confirmed COVID-19 infection, but who did not show any symptoms at the time of inclusion in the study and were themselves PCR-negative, were included. All patients were offered standard symptomatic treatment in case of the appearance of symptoms of the disease, as well as VIROSTOP nasopharyngeal spray containing an extract from the Cistus creticus plant in combination with other extracts in a dose of 3 applications per day.

Based on their voluntary decision, 182 subjects participated in the study, of which 108 were in the monitored group (standard treatment + application of VIROSTOP nasopharyngeal spray with Cistus creticus ) and 74 in the control group (standard treatment only). At the beginning of the study, there were no statistically significant differences in the age and gender of the subjects between the groups.

Data collection included demographics, comorbidities, comedications , and lifestyle factors. Data on symptom severity were subsequently collected every other day using the Wisconsin Upper standardized questionnaire Respirators Symptom Survey (WURSS24), while the last filling took place on the 12th day after inclusion in the study.

PCR tests to confirm SARS-CoV-2 infection were performed on the day of study entry and then on day 10 ( ± 2).

  • The primary aim of the study was to determine the rate of PCR test positivity in both groups.
  • The secondary objective was to monitor the development of standardized symptomatic scores in both groups.

Clinical study results

Results of PCR tests on 10 (±2). Day

At the time of the second PCR testing on day 10±2, none of the subjects from the study group became PCR positive, in contrast to 5.4% of the subjects from the control group. 

IgA positivity was monitored , which confirmed the presence of antibodies in up to 19 subjects from the monitored group and only 7 from the control group. It follows that, while the virus was not detected by the PCR test in these volunteers, among users of VIROSTOP nasopharyngeal spray with Cistus extract creticus developed a significantly better immune response.

Difference in composite score of patient-reported symptom severity

Comparison of symptom intensity according to Wisconsin Upper Respirators Symptom The survey showed that while the severity of symptoms was approximately the same on the second day, from the 4th to the 12th day of follow-up, the symptoms in the monitored group were considered less severe than in the control group. However, during the study, no significant differences were found in the amount of non-steroids used antiphlogistic drugs (NSAIDs).