COMPARATIVE MEMORY-ENHANCING ACTIVITY OF TWO CISSUS SPECIES: Cissus arguta HOOK.F. AND Cissus quadrangularis L. (VITACEAE)

ABSTRACT Memory dysfunction refers to the deterioration of cognition that affects the ability to reason, remember, make decisions, and communicate. Strategic Acetylcholinesterase enzyme inhibition helps in combating age-related neuronal degeneration that leads to memory loss. Some Cissus species have been reported for memory-enhancing activity, but there is still a dearth of research for this genus. Hence, the memory-enhancing activity of Cissus arguta and Cissus quadrangularis will be assessed. The plant samples (leaves and stems) were air-dried, pulverised, extracted to obtain methanolic extracts, concentrated in vacuo, and the extracts were subjected to in vitro acetylcholinesterase inhibitory activity using a modified Ellman’s colorimetric assay method with eserine as the standard drug. The most active crude extract was then partitioned into n-hexane, dichloromethane, and methanol fractions and investigated for in vitro acetylcholinesterase inhibitory activity. All extracts had acetylcholinesterase inhibitory effect but the highest inhibition was observed in Cissus arguta leaf crude extract (IC50 = 0.23 ± 0.02 mg/mL), followed by Cissus quadrangularis stem extract (IC50 = 0.47 ± 0.02 mg/mL), Cissus quadrangularis leaf extract (IC50 = 0.85 ± 0.02 mg/mL) and Cissus arguta stem extract ((IC50 = 3.82 ± 0.23 mg/mL). The methanol fraction of Cissus arguta leaf extract showed promising acetylcholinesterase activity with an IC50 value of 0.06 ± 0.004 mg/mL. All values are comparable with the standard drug, eserine (IC50 = 0.04 ± 0.001 mg/mL). Cissus arguta and Cissus quadrangularis crude extracts possess memory-enhancing activity and are potential sources of drug candidates that can be harnessed in drug discovery to manage neurodegeneration and memory loss.