The methanolic extract of raw Abrus precatorius (Jequirity bean, red- and black-coloured seed coat) seeds contains a total phenolic content of 14.2 ± 0.39 g catechin equivalent/100 g extract. An analysis of phenolic profile revealed the presence of syringic acid, caffeic acid and (−)-epicatechin in the methanolic extract of A. precatorius seeds. Encouraging levels of ferric reducing/antioxidant power (FRAP, 1247 mmol Fe[II]/mg extract), inhibition of β-carotene bleaching (53.37%), 2,2-Diphenyl-1-picryl-hydrazyl (DPPH, 62.13%) and superoxide (64.47%) radical scavenging activities were exhibited by the extract of raw samples. Inhibition characteristics of 68.69%α-amylase and 51.74%α-glucosidase enzyme were also recorded under in vitro starch digestion bioassay. Sprouting + oil-frying caused a significant increase in the total phenolic content and also substantially improved the antioxidant and free radical scavenging capacities, while soaking + cooking as well as open-pan roasting treatments showed diminishing effects.