Cholinesterase-inhibiting Potential and Anti-BACE1 Activities of Edible Leaves of Selected Thai Local Plants

Abstract

Alzhiemer’s disease (AD) is common amongst the elderly and is associated with decline in brain functions in terms of memory and cognitive loss. The causes of the disease may occur through loss of presynaptic markers of cholinergic system and deposition of amyloid fibrils in the brain. Cholinesterases (ChEs) including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are the key enzymes controlling degradation of neurotransmitters, acetylcholines (AChs), in cholinergic hypothesis. Whereas overproduction of b-secretase (BACE1) can generate insoluble b-amyloid peptides. Thus, retardation on enzyme reactions can lead to potential AD prevention. The aim of this research was to investigate in vitro anti-AD activity through key enzymes inhibitions from Thai local plants with edible sour leaves, including Garcinia cowa Roxb., Spondias pinnata (Linn.f.) Kurz, Syzygium gratum (Wight) S.N. Mitra., Tamarind indica L. and Cratoxylum formosum (Jack) Dyer. Leaves were extracted in organic solvents with different polarity index values (ethanol and hexane). As results, all plants possessed different degrees of anti-ChEs activity, in which ethanolic extracts of Spondias pinnata and Tamarind indica exhibited significantly higher ChEs inhibitory activities than Syzygium gratum, Garcinia cowa and Cratoxylum formosum, respectively. Interestingly, most hexane extracts exhibited higher anti-AChE activities than ethanol extracts, while the contrary results were observed in anti-BChE activity. Besides, only Cratoxylum formosum, Garcinia cowa and Tamarind indica extracts possessed anti-BACE1 activity. The information received from this study would be great support of future drug development or nutraceutical agents against AD occurrence regarding its cholinergic and b-amyloid formation hypotheses.