Polyphenolic extracts from Viola x wittrockiana show antidiabetic properties and reduce fat storages of Caenorhabditis elegans

Diabetes mellitus is an important health problem in our society that can cause severe complications or even death when untreated. Digestive enzymes such as pancreatic lipase and α-glucosidase play a major role in controlling the levels of fatty acid and carbohydrates assimilated. Advanced glycation end products (AGEs) are very unstable reactive compounds that contribute to endothelial and vascular complications in T2D.

Caenorhabditis elegans is a model organism widely used to evaluate functional foods and bioactive compounds that shares 60-80% of its genome with humans.

It has been shown that edible flowers own interesting properties that could make them suitable for developing new drugs. Viola x wittrockiana has shown to have many interesting properties due to its polyphenol-based composition.

The antidiabetic potential of the extract was quantified by in vitro inhibition of lipase and a-glucosidase; the capacity of the extract to inhibit AGEs formation by a non-enzymatic reaction was also evaluated. To furtherly test these antidiabetic properties, an in vivo assay with C. elegans was performed.

Viola showed lower IC₅₀ values in the a-glucosidase assay than the reference drug acarbose and higher inhibition AGEs formation potential than the reference substance aminoguanidine, they also obtained important values inhibiting lipase. Moreover, the extract lowered fat storages of C. elegans with no significant differences (p<0.005) to negative control.

The flowers of Viola x wittrockiana can be considered as source of polyphenol bioactive compounds with interesting properties as functional foods in the prevention and improvement of chronic diseases such as diabetes.