Comparative Analysis of Radish Varieties: Effects on Sugar Metabolism and Antioxidant Enzymes

This study investigated the in vitro antidiabetic and antioxidant properties of three radish varieties—white radish (FBT), red radish (FKT), and black radish (FST)—sourced from Konya. The evaluation encompassed several key biological activities. Total flavonoid content (TFC) and total phenolic content (TPC) were measured to establish the phytochemical composition. Antioxidant capacity was comprehensively assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and iron chelation activity (FCA) assays. Antidiabetic activity was determined by quantifying the inhibition of the α-amylase and α-glucosidase enzymes. Among the samples, red radish (FKT) exhibited the highest TFC (1.27 mg KE/g) and TPC (55.36 mg GAE/g), followed by black radish (FST) and white radish (FBT). Antioxidant activity, assessed via DPPH, ABTS, and iron chelation assays, revealed that FST had the strongest DPPH radical scavenging activity (84.32%; IC₅₀ = 636.6 μg/mL), while FKT showed superior ABTS inhibition (83.79%; IC₅₀ = 144.5 μg/mL) and FBT iron chelation capacity (74.04%; IC₅₀ = 677.2 μg/mL). In terms of antidiabetic potential, FKT demonstrated the most potent α-amylase inhibition (97.36%; IC₅₀ = 2.07 mg/mL) and α-glucosidase inhibition (84.18%), indicating strong enzyme inhibitory activity. FBT showed moderate activity on most assays, while FST displayed notable antioxidant properties but comparatively lower antidiabetic effects. In conclusion, red radish (FKT) emerged as the most promising candidate among the three varieties, exhibiting the highest levels of bioactive compounds and the strongest antidiabetic and antioxidant activities. These findings suggest that FKT may offer valuable health benefits and could be further explored for its therapeutic potential in managing oxidative stress and diabetes-related conditions.