The current research work was conducted in order to probe into the biochemical and toxicological characterisation of methanol and dichloromethane (DCM) extracts of Bougainvillea glabra (Choisy.) aerial parts. Biological fingerprints were assessed for in vitro antioxidant, key enzyme inhibitory and cytotoxicity potential. Total bioactive contents were determined spectrophotometrically and the secondary metabolite components of methanol extract was assessed by UHPLC mass spectrometric analysis. The antioxidant capabilities were evaluated via six different in vitro antioxidant assays namely DPPH, ABTS (free radical scavenging), FRAP, CUPRAC (reducing antioxidant power), phosphomolybdenum (total antioxidant capacity) and ferrous chelating activity. Inhibition potential against key enzymes urease, α-glucosidase and cholinesterases were also determined. Methanol extract exhibited higher phenolic (24.01 mg GAE/g extract) as well as flavonoid (41.51 mg QE/g extract) contents. Phytochemical profiling of methanol extract identified a total of twenty secondary metabolites and the major compounds belonged to flavonoids, phenolics and alkaloid derivatives. The findings of antioxidant assays revealed the methanol extract to exhibit stronger antioxidant (except phosphomolybdenum) activities. Similarly, the methanol extract showed highest butyrylcholinesterase and urease inhibition. The DCM extract was most active for phosphomolybdenum and α-glucosidase inhibition assays. Moreover, both extracts exhibited significant cytotoxic potential against five (MCF-7, MDA-MB-231, CaSki, DU-145, and SW-480) human carcinoma cell lines with half maximal inhibitory concentration values of 22.09 to 257.2 μg/mL. Results from the present study highlighted the potential of B. glabra aerial extracts to be further explored in an endeavour to discover novel phytotherapeutics as well as functional ingredients.