The synthesis of magnesium hydroxide nanoparticles (Mg(OH)<inf>2</inf> NPs) using plant extracts are known to be a practical, economical, and an environmentally friendly approach. In this work, Mg(OH)<inf>2</inf> NPs were synthesized using aqueous leaf extract of Tinospora cordifolia, a medicinal plant commonly found in India. The synthesized Mg(OH)<inf>2</inf> NPs were characterized using various spectroscopic techniques. The ultraviolet–visible (UV–Vis) absorption peak of the Mg(OH)<inf>2</inf> NPs was detected at 289 nm, Fourier transform infrared (FTIR) analysis confirmed the presence of various functional groups, and X-ray diffraction (XRD) patterns revealed the well-crystallized structure of the Mg(OH)<inf>2</inf> NPs. High-resolution transmission electron microscopy (HR-TEM) and scanning electron microscopy (SEM) analyses depicted spherical morphology and an average particle size (PS) of 27.71 nm. The energy-dispersive X-ray (EDX) analysis confirmed the presence of C, O, and Mg elements, and the X-ray photoelectron spectroscopy (XPS) survey spectrum confirmed the elements for the Su 1 s peak at 280.2 eV. The dynamic light scattering (DLS) analysis displayed an average PS of 54.3 nm, and the Zeta potential (ZP) was of 9.89 mV. The fabricated Mg(OH)<inf>2</inf> NPs displayed notable antibacterial activity against S. epidermidis, E. coli, and S. aureus. In addition, these NPs exhibited strong antioxidant properties (> 75%) based on DPPH, ABTS, and hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>) assays. Further, the same NPs exerted a potent anti-inflammatory activity (> 65%) based on COX-1 and COX-2 evaluations. The anti-Alzheimer’ disease (AD) potential of Mg(OH)<inf>2</inf> NPs was assessed through effective inhibition (> 70%) of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities. Molecular docking (MD) studies confirmed that caryophyllene has higher binding affinity with AChE (−5.3 kcal/mol) and BuChE (−6.4 kcal/mol) enzymes. This study emphasizes the green synthesis of Mg(OH)<inf>2</inf> NPs using T. cordifolia as a plant source and highlights their potential for biomedical applications. © 2024 Elsevier B.V., All rights reserved.