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

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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, Diabetes, Hyperglycemia, Phytochemistry, Antioxidant, phenolic compounds.