Researchers in Greece have demonstrated the antiviral effects of Cretan fragrant plant oil on severe acute coronavirus syndrome 2 (SARS-CoV-2) – the agent responsible for coronavirus disease 2019 (COVID). -19).
The team showed that a mixture of essential oils from Mediterranean thyme (Thymbra capitata L. Cav.), Greek Sage (Salvia fruticosa mill.), and Cretan dittany (Origanum dictamnus L..), exhibiting remarkable antiviral activity against SARC-CoV-2 in Vero E6 cells.
Furthermore, in a confirmatory study involving patients with mild COVID-19, administration of the essential oil mixture significantly improved both general and local symptoms.
The study was conducted by researchers from the University of Crete in Heraklion, Democritus Thrace University in Alexandroupolis, and the University General Hospital in Alexandroupolis.
Elias Castanas and colleagues suggest that if the findings are confirmed in clinical trials, the essential oil mixture (known as CAPeo) may provide a new, inexpensive alternative for the treatment of COVID- 19 mild.
A pre-printed version of the research paper can be found on the medRxiv * server, while the article is subject to peer review.
Cretan dittany leaves, Origanum dictamnus. Image credit: Michalis Koulieris / Shutterstock
Unmet need for effective treatments
Since the beginning of the COVID-19 revolution in Wuhan, China, in late 2019, unparalleled efforts have been made to develop effective vaccines and treatments to protect against and treat SARS-CoV-2 infection.
Safe and effective vaccines have now begun to emerge and there are a number of medications at different stages of clinical and clinical development.
However, Castanas and colleagues say that while there are some effective treatments for hospitalized patients in intensive care units, the need for cheap, safe, and effective treatments for patients who are not severely outside the setting. hospitals still unfulfilled.
“Accordingly, drug reproduction for candidates working against known or predicted SARS-CoV-2 protein actions has been demonstrated, and natural results have also been confirmed,” the team wrote.
Previous studies on CAPeo
Castanas and colleagues recently demonstrated that CAPeo was effective in reducing the severity and duration of viral infections of the upper respiratory tract in humans. In vitro studies of influenza and human rhinovirus 14 (HRV14) showed that treatment with CAPeo inhibited the nuclear transport of viral nucleoproteins and disrupted viral protein transcription.
In addition, the researchers have already reported the safety of CAPeo (1 ml / day of 1.5% CAPeo in extra virgin olive oil) in humans and animals.
“Here, we propose CAPeo as a potential novel agent, for safe and effective therapeutic management of mild cases of COVID-19,” they say. “It demonstrates remarkable antiviral properties against Influenza A and B and HRV14 rays, while being safe both in experimental animals and in humans.”
What did the researchers do?
Now, the team has extended the previous studies to SARS-CoV-2 and on the effect of CAPeo on virus-infected Vero E6 cells.
The researchers also conducted an empirical study in which 17 patients with SARS-CoV-2 were tested with PCR and COVID-19 mild.
What did they find?
The study found that CAPeo exerted significant antiviral activity against SARS-CoV-2 in Vero E6 cells at concentrations similar to those previously reported by the researchers..
CAPeo reduced viral transmission into the culture medium by more than 80%. This effect continued (although it was about 35% less) when CAPeo concentrations were reduced to 1% of the recommended dose for humans.
Interestingly, a prophylactic effect was also observed when Vero E6 cells were ingested with different concentrations of CAPeo 2 hours before infection.
“CAPeo, in addition to potential therapeutic action, may have a prophylactic effect against the SARS-CoV-2 virus,” the team writes.
The proof-of-concept study
Inspired by the results, Castanas and colleagues performed the next concept-testing intervention involving 17 SARS-CoV-2-positive patients with mild symptoms of COVID-19.
The depth and duration of general and local symptoms among participants were assessed for 14 days.
“We have chosen this interval because previous studies report on self-resolution of COVID-19 mild cases in 14 or 14-21 days and the persistence of the virus in upper respiratory tract samples for approx. on ten days, ”explained the researchers.
Since the study did not include a control group, the team compared the evolution of disease symptoms among the participants compared with those reported in previous studies of non-hospitalized patients.
What were the results?
Administration of 1 mL daily of 1.5% CAPeo in olive oil significantly improved general and local symptoms among participants by the end of the study.
At the start of the study, the main common symptoms included headache, myalgia, weakness, and fever, according to previous reports, the team says.
However, compared with other study findings, all but one patient had low fever (below 37.5 ° C).
Frequency of other symptoms (including gastrointestinal, respiratory and ear nose and throat [ENT]) also low, and moderate intensity.
The study also found that important common symptoms of COVID-19 – i.e. headache, fatigue, fever – were abruptly resolved. In contrast, previous studies found that headaches and fatigue (but not fever) persisted at 14 days and beyond, the team said.
In addition, most general and local symptoms had largely resolved by the end of the first week.
The authors recommend that CAPeo be tested in clinical trials
The researchers say the findings suggest that CAPeo has strong antiviral and prophylactic activity against SARS-CoV-2.
“We suggest that CAPeo, pending further confirmation of results through a prospective randomized controlled trial, could be a valuable addition to the prevention and therapeutic management of COVID-19 mobile patients,” the team finishes.
* Important message
medRxiv publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be seen as final, guiding health-related clinical / behavioral practice, or be treated as information established.