Terminalia citrina (T. citrina) belongs to the Combretaceae family and is included in the class of medicinal plants in tropical countries such as Bangladesh, Myanmar, and India. The antioxidant activities of lyophilized water (WTE) and alcohol extracts (ETE) of T. citrina fruits, their phenolic content by LC‐HRMS, and their effects on cholinesterases (ChEs; AChE, acetylcholinesterase, and BChE, butyrylcholinesterase) were investigated. Especially ten different analytical methods were applied to determine the antioxidant capacity. Compared with similar studies for natural products in the literature, it was determined that both WTE and ETE exhibited strong antioxidant capacity. Syringe and ellagic acids were higher than other acids in ETE and WTE. IC50 values for ETE and WTE in DPPH radical and ABTS⋅+ scavenging activities were calculated as 1.69–1.68 μg mL−1 and 6.79–5.78 μg mL−1, respectively. The results of the biological investigations showed that ETE and WTE had an inhibition effect against ChEs, with IC50 values of 94.87 and 130.90 mg mL−1 for AChE and 262.55 and 279.70 mg mL−1 for BChE, respectively. These findings indicate that with the prominence of herbal treatments, T. citrina plant may guide the literature in treating Alzheimer's Disease, preventing oxidative damage, and mitochondrial dysfunction.