The occurrence of cases of diabetes in the family, including complications from the disease that led to the loss of loved ones, led food engineer Michele Christine Machado de Oliveira to readily accept the focus suggested by her advisor, professor Marcelo Alexandre Prado, to the master's thesis: investigate the antioxidant and hypoglycemic effects (lowering glucose levels) of aqueous canary seed extract. What sets this dissertation apart is the fact that there are several popular reports about the consumption of so-called “birdseed milk” as an alternative treatment for diabetes, but scientific studies on the seed are scarce.

“Reports on the internet speak of 'birdseed milk', when in fact it is an aqueous extract. For the project, I followed exactly the way people prepare this extract, based on an average of the dosages reported in various sources”, says Michele Oliveira, who presented the dissertation at the Faculty of Food Engineering (FEA) at Unicamp. “The birdseed was left to soak in water for twelve hours, in the refrigerator, with the first change of water to blend the seeds in the blender; After the filtering process, the extract was administered to laboratory animals.”

The author notes in the dissertation that, since 1997, birdseed (Phalaris canariensis L.) has been evaluated as human food and functional ingredient in the food industry. Ethnopharmacology (science that studies popular knowledge about drugs) reports its use as a blood pressure-lowering agent and, in tea form, as an adjunct in the treatment of hypertension, diabetes mellitus and high cholesterol levels, associated or not with other forms of conventional therapy. Specifically, “birdseed milk” would be used to control blood glucose levels in diabetic individuals.

The results obtained by Michele Oliveira in this first research focused on such specificity, however, contradict popular belief. “The birdseed and its extract showed nutritional potential as sources of fiber, starch, proteins and polyunsaturated fatty acids (omega-6). But the aqueous extract, despite the phenolic compounds, showed intermediate antioxidant activity, not relevant to combating diabetes induced in laboratory animals. In other words: it did not control glycemic levels, it had no effects on body mass, water and feed consumption, as well as on biochemical, electrolyte and hematological parameters.”

The work carried out by the food engineer was thorough, starting from the characterization of both the seed and the aqueous extract in relation to proteins, lipids, moisture, etc. Phenolic compounds were determined using the Folin - Ciocalteu method and antioxidant activity was evaluated using three methodologies (ABTS, DPPH and ORAC); The assessment of hypoglycemic activity in animals was carried out with treatments for 28 and 87 days, using dosages of the aqueous extract of 250, 500 and 1.000 milligrams per kilogram (mg/kg), orally. The animals were monitored weekly for body mass, blood glucose and water and food consumption; After the experiments, examinations of influence on the mass of organs, biochemicals and blood and urine made it possible to verify the action of birdseed extract on diabetes.

According to Michele, an interesting result in the identification of fatty acids in the aqueous extract was the 53% level of linoleic acid (omega-6), a very rich source that may actually be contributing to the reduction of the glycemic index of this population. “In terms of antioxidant activities, birdseed is very close to rice, barley, oats and sorghum, constituting an intermediate activity. In the aqueous extract, however, the amount of proteins was maintained, but the amount of lipids, fibers, ash and starch decreased due to the removal of skins, sieving and filtration, and the result in terms of antioxidant activity and phenolic compounds it was not as high as expected – we did not see the anti-diabetes properties that the population believes in.”

TESTS IN VIVO

For the in vivo tests, the author had the help of her co-supervisor, doctor Débora Barbosa Vendramini Costa, and the team from the Division of Pharmacology and Toxicology at CPQBA (Multidisciplinary Center for Chemical, Biological and Agricultural Research) at Unicamp, in order to certify the non-toxicity of the aqueous extract of birdseed, and then worked with six groups of animals, taking care of the preparation and administering the popular solution daily. “The non-toxicity is interesting for future work, as we could study higher doses of the extract – two thousand milligrams per kilogram – and perhaps obtain a significant effect. More studies are needed to be sure that the extract really does not have any action against diabetes.”

The food engineer found that diabetic animals, whether they received treatment or not, showed the same behaviors: they ate, drank water and urinated excessively, at the same time as they lost weight. “With treatment, the effects were relatively lessened – they drank and urinated less – but without significance in the overall measurement. It may be that some people, when taking the extract, actually feel this decrease, but it is a very specific effect: in the blood glucose test, compiling data from 28 and 87 days of treatment, we did not see any important changes.”

In Michele Oliveira's opinion, the 87-day test, suggested by the qualification panel to evaluate the survival of the animals, was conclusive of her entire study. “The 28-day test is an initial step to evaluate the glycemic increase characteristic of diabetes, a disease that can bring other complications over time, such as vascular problems. At the end of the longer experiment, I noticed that the animals, in addition to changes in liver and kidney enzymes, had cataracts in one or both eyes and became more aggressive.”

Considering that this is the first work on the aqueous extract of birdseed and the limited time of the master's degree, the author concluded the dissertation with suggestions for future research, such as carrying out the extraction with other types of solvents and evaluating the antioxidant activity and action antidiabetic. “Another suggestion is to study the properties of birdseed bark, despite the popular belief that it is carcinogenic and, therefore, birds only eat the inside of the seed. In the animal test, I was concerned about removing as much of the shells as possible, when the antioxidant compounds were probably on the outside or even in the first water that was changed. I also suggest studies for other diseases, such as cancer, hypertension and obesity, and we see websites citing the benefits of birdseed in cases of cirrhosis, obesity and muscle tone, among other pathologies.”

Publication

Dissertation: “Characterization of the aqueous extract of birdseed (Phalaris canariensis L.) and evaluation of the antioxidant and hypoglycemic effects”

Author: Michele Christine Machado de Oliveira

Advisor: Marcelo Alexandre Prado

Each: Faculty of Food Engineering (FEA)