Phenolic compounds of Senna alata extracts and their Inhibitory activity of α-Glucosidase

---

Résumé

Diabetes is a growing global public health problem, affecting millions of people worldwide. Conventional treatments, though effective, have notorious limitations, such as undesirable side effects, high cost and limited accessibility for certain populations. This situation calls for the exploration of alternative or complementary natural solutions. With this in mind, researchers have embarked on a frantic search for new antidiabetic molecules derived from plant flora. Senna alata, a medicinal plant widely used in traditional medicine in Burkina Faso, is renowned for its many pharmacological properties, such as its antidiabetic potential. The present work therefore focused on the phytochemical study and evaluation of the antidiabetic potential of Senna alata. To this end, different extracts were prepared using the plant’s leaves and flowers. The different chemical groups present in the prepared extracts were highlighted by combining two complementary methods such as thin layer chromatography (TLC) and colorimetric tests with characteristic reagents. Total phenolic and flavonoids were determined using Folin-Ciocalteu reagent (FCR) and aluminum trichloride (AlCl3) respectively. Antiradical activity was assessed using the DPPH method. The antidiabetic potential of the various extracts was assessed by monitoring their inhibitory effect on α-glucosidase enzyme activity. The results of the chemical screening revealed the presence of many secondary metabolites such as flavonoids, tannins, quinones and alkaloids in the decoction and macerated extracts. The various phytoconstituent assays revealed that the hydroalcoholic extract of Senna alata leaves contained the highest levels of these compounds, with values of 284.06±2.69µg EGA/mg (total phenolic compounds) and 46.73±1.11μg EQ/mg (total flavonoids), followed by the aqueous and hydroalcoholic extracts of flowers. Assessment of antioxidant activity by the DPPH assay revealed a high DPPH● radical reducing capacity, particularly in the leaf hydroalcoholic extract (IC50 = 192.74±0.41µg/mL). Results for antidiabetic activity showed that Senna alata leaf extracts all have a higher antihyperglycemic potential than acarbose (IC50 = 280.73±1.97µg/mL), the most active being the hydroalcoholic extract with an IC50 = 52.01±1.65µg/mL. These results therefore confirm the therapeutic potential of Senna alata, particularly in the management of diabetes, and open up prospects for the development of natural treatments in Burkina Faso.

Mots-clés

Senna alata, phenolic compounds, flavonoids, α-glucosidase inhibition, antidiabetic activity, antioxidant activity, DPPH radical scavenging, phytochemical screening, medicinal plants, diabetes mellitus, leaf and flower extracts, hydroalcoholic extract, acarbose comparison, tannins, alkaloids, quinones