Plant has hepatoprotective, anti-inflammatory and schistosomicidal properties
A study developed at the Faculty of Food Engineering (FEA) at Unicamp used two different techniques [pressurized liquids and supercritical fluids] to extract lignans, bioactive compounds present in the species Phyllanthus amarus, a medicinal plant popularly known as stonebreaker. The second method provided the best result, being responsible for obtaining extracts with up to 35% of the intended substance, an index considered very significant for a crude extract. The work, supervised by professor Julian Martínez and co-supervised by researcher Vera Lucia Garcia, from the Multidisciplinary Center for Chemical, Biological and Agricultural Research (CPQBA), was carried out in the context of the doctoral thesis by food engineer Rúbner Gonçalves Pereira.
The research conducted by Pereira opens up the prospect of using lignans in the future production of pharmaceuticals. According to scientific literature, these bioactive compounds have hepatoprotective, anti-inflammatory and schistosomicidal properties, that is, they act to combat the parasite. schistosoma mansoni, which causes schistosomiasis. “Obviously, we still have a long way to go before developing a drug from lignans. But we have already taken an important step”, defines the author of the study.
According to Pereira, the two methods he tested are new compared to others that have been applied by the industry for several decades. Both pressurized liquids and supercritical fluids, adds the researcher, have been used by industry in other countries, but in Brazil these techniques are currently only used on a laboratory scale. “These are very interesting technologies because they improve the characteristics of the solvents and speed up the extraction time, compared to conventional techniques”, explains the author of the thesis.
Simply put, to extract compounds from a plant it is necessary to find a solvent capable of solubilizing the substances of interest. The result will depend on the degree of interaction between the solvents and the compounds. With the use of pressurized liquids, informs the author of the thesis, it is possible to modify several parameters present in the process, including temperature. “We tested different temperatures, until we reached the one that provided the best extraction rate. The same was done with supercritical fluids, but also in relation to the pressure parameter”, explains Pereira.
At the end of the experiments, the food engineer concluded that, in the case of pressurized liquid, temperature had no significant influence on extraction. In practice, any temperature within the tested range [35 and 80 degrees Celsius] can be applied to extract lignans. “In this case, the recommendation is to opt for the lowest temperature, as this will result in less energy use in the process”, ponders the researcher.
Regarding the supercritical fluid, several variables were analyzed. The main conclusion was that the combination of lower temperature and intermediate pressure level provided the best result. “In this case, the supercritical fluid was much more selective. The method allowed obtaining an extract richer in lignans, with a concentration of 35%. The technique using pressurized liquid generated an extract with a concentration that varied from 0,2% to 4%”, reveals Pereira.
Another advantage of the method that uses supercritical fluid, according to the thesis author, is that the solvent is removed during the process. When using pressurized liquid, an additional step must be taken to remove the solvent. The food engineer explains that previous work involving the extraction of lignans was carried out by areas other than engineering. In these cases, the focus of the research was not the quantification of the compounds, but rather their biological activity. “For this reason, we had difficulty in establishing comparisons, but the amount of lignans we obtained is very significant”, reinforces Pereira.
In his thesis, the researcher also analyzed the cost of the lignan extraction processes. What he found was that the acquisition of plants and solvents represents 90% of the total production cost. Of this 90%, 67% corresponds only to the cost of acquiring the stone breaker. “This occurs because the plant is mainly used domestically in Brazil. We do not have large-scale suppliers for the industry. Therefore, it is more difficult to find this raw material, which in turn also costs more”, analyzes Pereira, who received a scholarship granted by the Coordination for the Improvement of Higher Education Personnel (Capes), a development agency of the Ministry of Education.
