Pharmacist confirms antioxidant, antihypertensive and antidiabetic potential of shimeji

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Image Editing Alex Calixto Paulo Cavalheri

Photography Lúcio Camargo Public Relations

**Different stages of experiments carried out in the laboratory of the Faculty of Food Engineering: researcher analyzed the combination of enzymes and reaction times**

Pharmaceutical company confirms the antioxidant , antihypertensive , and antidiabetic potential of shimeji mushrooms.

Peptides obtained from hydrolyzed mushroom protein have shown beneficial effects on the human body

A scientist from Unicamp has identified the shimeji mushroom ( Pleurotus spp .) as a promising source of bioactive peptides with antihypertensive, antidiabetic, and antioxidant properties. This conclusion is based on the thesis of Daniela Cavenaghi, defended in the Postgraduate Program in Food Science at the Faculty of Food Engineering (FEA). The discovery represents an important step towards the development of products based on this macrofungus.

Bioactive peptides are the result of specific sequences of amino acids present in a protein. These substances have beneficial effects on the body that go beyond their nutritional function. Cavenaghi obtained the peptides from shimeji through enzymatic hydrolysis, a process in which enzymes are used to break down larger molecules into smaller compounds. The researcher used the enzymes Flavourzyme, Alcalase and Neutrase, which are widely used in the food industry. For each type of bioactivity, the researcher sought the most appropriate enzymatic treatment, which involved analyzing the combination of enzymes and reaction times.

After obtaining the peptides, Cavenaghi, a pharmacist and professor at the Federal Institute of Education, Science and Technology of Mato Grosso (IFMT), checked whether they had antihypertensive, antidiabetic and antioxidant properties. All three functions were identified.

The researcher also simulated a digestion process, verifying that these properties remained intact. “This is important because, when we produce a peptide that has systemic activity, we need to ensure that there is activity when it reaches the bloodstream and is distributed throughout the body to reach potential receptors,” she explains.

**Pharmacist Daniela Cavenaghi: development of therapeutic products will be new research target**

The research is focused on developing therapeutic products, although the doctorate is only an initial study in this regard. In the case of antihypertensive drugs, Cavenaghi points out, there are side effects that in some cases make patients suffer from the treatment. “When we have a bioactive peptide, and it also comes from a natural source, the adverse effects will be reduced in relation to the synthetic drug.”

The thesis was supervised by Professor Ruann de Castro, from the Department of Food Science and Nutrition at FEA. Castro is one of the people responsible for the Food Biochemistry Laboratory, where there is a line of research on alternative proteins, given the importance of a diet rich in different types of foods. Mushrooms are a source of this type of protein.

The professor explains the reasons why research into peptides from this food is necessary. “In addition to their nutritional function, peptides can perform certain types of physiological functions within our bodies. These sequences, when present in native proteins, do not perform bioactivity. They only begin to perform them when they are released. This can occur through different types of processes, such as enzymatic hydrolysis.”

Castro points out that there are two products already well-known to the Brazilian population that can be marketed in their hydrolyzed forms: collagen and whey protein . Conducting more in-depth studies involving different sources, such as mushrooms, is essential for other products to reach the market.

Bioactivity

To investigate the antioxidant properties, Cavenaghi sought to evaluate the bioactivity of the peptides using three distinct methods. The hydrolyzed mushroom protein demonstrated activity in all three cases. These properties were enhanced after simulated in vitro digestion , with an increase of up to 150% in the elimination of DPPH, a type of free radical.

The antihypertensive properties were manifested through the inhibition of the angiotensin-converting enzyme (ACE). By inhibiting ACE, there is a relaxation of the blood vessels, helping to control blood pressure. The researcher identified the inhibition of ACE by comparing the hydrolyzed protein with the non-hydrolyzed one. Protein hydrolysates demonstrated a greater degree of ACE inhibition. There was a variation in enzyme inhibition between 15,76% and 50,87%, depending on the enzyme combination used to obtain the hydrolysates.

**Professor Ruann de Castro, supervisor of the study: peptides perform physiological functions in the body**

The antidiabetic properties were demonstrated through the inhibition of the enzymes α-amylase and α-glucosidase. These enzymes, responsible for the digestion of carbohydrates, end up, when inhibited, reducing the absorption of simple sugars and, consequently, controlling blood glucose levels. The comparison of the action of the hydrolyzed protein with that of the non-hydrolyzed protein also showed better results in the case of the former.

The values reached 72% inhibition for α-amylase and were above 62% for α-glucosidase. Acarbose, under the same conditions, reached 84% inhibition.

“We work with Acarbose, which is the reference drug. Regarding bioactivity, we found quite satisfactory levels, including values comparable to those of the reference drug, within our study standards. Acarbose is very strong in terms of this inhibition because it is synthetic. Peptides, as they are natural substances, have a slightly lower inhibition, but interesting inhibitions when we think about the application”, concludes Castro.

And does eating it work? The professor points out that shimeji has been consumed for thousands of years and brings many benefits, as it is a food rich in vitamins, minerals and proteins. However, the author of the thesis warns: “Consuming it whole is important, however, this does not mean that, by consuming it, you will no longer need to take medication for blood pressure and diabetes.”

Doctorate Agreement

Cavenaghi's doctorate was made possible through the Interinstitutional Doctorate Program (Dinter) of the Coordination for the Improvement of Higher Education Personnel (Capes), involving Unicamp and IFMT. According to one of the requirements of the call for proposals, the research projects considered must contribute to local development. For this reason, the mushrooms used by the scientist were purchased from a rural settlement in the city of Campo Verde (MT), which sells the products at an organic fair held in Chapada dos Guimarães.

The study results are being published in scientific articles. The publication on the antihypertensive properties appeared in the journal Process Biochemistry . The article on the antioxidant properties appeared in the journal Food and Humanity . The results regarding the antidiabetic properties are still undergoing a preparation process for publication.