In vitro Antioxidant Effects and α -Amylase and α - Glucosidase Inhibitory Activity of Cissus polyantha Aqueous Extract

Cissus polyantha (Vitaceae) is a plant used in Cameroonian traditional medicine for the treatment of
diabetes. The aims of this study were to evaluate the in vitro antioxidant and antidiabetic activities of
the aqueous extract of Cissus polyantha leafy stems. The enzyme inhibitory activity was determined
in vitro on α-amylase and α-glucosidase enzymes, followed by confirmative study in vivo on normal
rats (oral starch and sucrose tolerance tests at doses of 111, 222 and 444 mg/kg). The ferric reducing
antioxidant power and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) antiradical activity of the extract were
examined to evaluate the antioxidant potential of the extract.The total content of phenols, flavonoids
and tannins of the extract were also determined. Results showed an inhibitory effect of the extract on
the α-amylase and α-glucosidase activity with IC50 values of 216.14 and 182.40 μg/mL respectively.
The extract at doses of 222 and 444 mg/kg induced a significant decrease in postprandial glycaemia
during the starch and sucrose tolerance tests. A remarkable antiradical activity of the extract was
obtained, although lower than that of the standard product. The aqueous extract of leafy stems of
Cissus polyantha has an interesting inhibitory activity on the α-amylase and α-glucosidase enzymes,
as well as an antioxidant potential, thus validating its use in traditional medicine for the treatment of
diabetes mellitus and its complications.