The methanolic extract of ox-eye bean [Mucuna gigantea (Willd) DC.] contained total free phenolic content of $14.80{pm}1.28$ g catechin equivalent/100 g extract dry matter. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1,023 mmol Fe[II]/mg extract), inhibition of ${eta}$-carotene degradation (59.35%) and radical scavenging activity against DPPH (72.12%) and superoxide (43.11%) were exhibited by the raw samples. Further, it also recorded 82.17% of ${alpha}$-amylase and 91.26% of ${alpha}$-glucosidase enzyme inhibition characteristics. Sprouting+oil-frying caused a apparent increase on the total free phenolic content and also significant improvement on the antioxidant and free radical scavenging capacity of methanolic extract, while soaking+cooking as well as open-pan roasting treatments showed diminishing effects. Moreover, inhibition of ${alpha}$-amylase and ${alpha}$-glucosidase enzyme activities was declined to 22.82 and 45.47%, respectively during sprouting+oil-frying treatment, which are more desirable for the dietary management of type II diabetic patients.