In-vitro antioxidant and antidiabetic potentials of Dianthus basuticus Burtt Davy whole plant extracts

Dianthus basuticus is a popular South African medicinal plant used in the management of diabetes mellitus. This study evaluated the antioxidant and antidiabetic potential of D. basuticus using an in-vitro model. The antioxidant activity was determined using iron chelation, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide anion radical scavenging abilities of the aqueous, ethanol and hydro-ethanol extracts of D. basuticus while the antidiabetic potential was assessed by evaluating the inhibitory effects of the extracts on the activities of α-amylase, α-glucosidase, maltase and sucrase. The aqueous extract displayed significantly higher (p < 0.05) DPPH (2.56 μg/mL) and superoxide radical (7.22 μg/mL) scavenging abilities while ethanol (10.56 μg/mL) and hydro-ethanol (6.95 μg/mL) extracts exhibited strongest hydroxyl radical scavenging and iron chelation activities respectively. The ethanol extract displayed significantly higher (p < 0.05) inhibition of α-amylase (34.02 μg/mL) while aqueous extract exhibited strongest inhibition of α-glucosidase (6.59 μg/mL), maltase (31.21 μg/mL) and sucrase (20.98 μg/mL). Hydro-ethanol and aqueous extract inhibited α-amylase and α-glucosidase in a mixed non-competitive and pure non-competitive manner respectively while the aqueous extract competitively inhibited both maltase and sucrase activities. It can be concluded that D. basuticus extracts possessed antioxidant and antidiabetic activities, and one of its mechanism of antidiabetic action is through the inhibition of diabetes-related enzymes.