Research conducted at the Butantan Institute seeks to identify a compound that can be used both in the prevention and treatment of arboviruses
Research carried out by scientists at the Butantan Institute, in São Paulo, found that the aqueous extract of propolis is capable of combating the replication of the zika, chikungunya and mayaro viruses. The 3 pathogens are transmitted by the bite of mosquitoes that circulate in Brazil and cause infectious diseases (arboviruses) for which there is still no vaccine or specific treatment available, which motivates the search for compounds with antiviral potential. The extract was tested in vitro and significantly reduced the viral load of the 3 viruses.
The study, conducted at (), was led by researchers from the Applied Toxicology Laboratory and the Butantan Parasitology Laboratory. The results were in the magazine Scientific Reports.
This is not the first time that the group has investigated the antiviral and antibacterial potential of propolis. A previous study by the team, carried out with a hydroalcoholic extract of the substance, had already indicated intense activity against the herpes, influenza and rubella viruses. Based on the first results, the scientists decided to evaluate whether the aqueous extract would have the same activity on other types of viruses that are also important from the point of view of public health in the country.
Extract preparation and analysis
To reach the results, the group used propolis produced by native stingless bees Scaptotrigona aff posticaoriginating from a colony in the Barra do Corda region, in Maranhão. Propolis was obtained by scraping the meliponiculture box, forming a kind of paste. This material was transported and frozen at a temperature of -20°C, forming a frozen propolis stone.
This stone was manually macerated until it became a granulated material, which was passed through sieves. Then, the product was ground to become an even finer compound, to pass through granulometric sieves again and turn into powder. Finally, the researchers added ultrapurified water to the powder and the material was centrifuged for 30 minutes to separate the wax from the liquid medium. The supernatant (the liquid phase on top) was filtered and the product was considered 100% purified.
To determine the antiviral action of propolis extract, the researchers infected Vero cells (a strain originating from monkey kidney, often used in this type of study), which were cultivated at 37°C in microplates. The growth and morphology of these cells were monitored by the team daily. “We contaminated the cultures with the 3 viruses in question and only applied the substance we wanted to analyze once, at a rate of 10% by volume. From then on, we carried out a serial dilution, that is, we reduced the amount of this solution to see what amount would prevent the virus from multiplying.”explained Silva Júnior.
The researchers observed that the purified propolis aqueous extract promoted a 16-fold reduction in the Zika viral load and a 32-fold reduction in the Mayaro virus. In the case of chikungunya, the reduction was even more significant, 512 times.
More research
For now, the results achieved are restricted to the laboratory environment, but research continues.
In a 2nd stage of the work, the group collected propolis month by month, to associate the final product with the flowering of each period. This is because the bee Scaptotrigona aff postica It uses plants from the Maranhão region, which are different from plants found in the Southeast, and therefore, the propolis obtained probably has specific components related to species endemic to the region.
“We have already observed that there are differences throughout the year. Now we want to identify when the substance with antiviral action appears, because we want to associate it with the plant that the bee uses to produce propolis.”said Silva Júnior.
It is important to highlight that the propolis in the study is different from the commercial ones found in pharmacies. The product sold to the consumer, in general, is an alcoholic extract that mixes all the components of propolis and, in most cases, usually comes from the species Apis mellifera (European bee), which predominates in apiaries. The propolis used in this research comes from the bee native to Brazil Scaptotrigona aff postica and compounds with antiviral activity are separated, purified and isolated.
Bioactives
The search for potential medicines in nature – the famous bioactive compounds – is one of the major focuses of science. Brazil has a very large area with extremely varied fauna and flora and using substances originating from our forest is very important, both from a scientific and economic point of view, as this can reduce the costs of the final product.
The researcher states that the objective of the research is to try to identify a compound that can be used both in the prevention and treatment of people infected by viruses: “We still don’t have the elements to get to that point, but the idea is to achieve both objectives”.
But there is still a long way to go. “If we are thinking about creating a possible medicine, many more studies will have to be done. This is a super important discovery, but the results were obtained in vitro. It will still be necessary to carry out in vivo research with mice and guinea pigs to verify whether the antiviral effect would be confirmed and, only later, begin research on human beings.”he declared.
The article Antiviral action of aqueous extracts of propolis from Scaptotrigona aff. postica (Hymenoptera; Apidae) against Zica, Chikungunya, and Mayaro virus can be read.
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