Effect of blanching on inhibition of cholinesterases and antioxidative properties of phenolic extracts of African lettuce (Launaea taraxacifolia)

Abstract

This study sought to assess the influence of blanching on the inhibition of key enzymes linked to neurodegeneration and the antioxidative properties of phenolic extracts of African lettuces. The phenolic extracts of blanched and unblanched African lettuces leaves were prepared using the mixture of absolute 1 M HCl and Methanol (1:1 v/v). Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) in vitro inhibitory properties, antioxidant properties (Fe²⁺ chelating ability, DPPH* radical scavenging ability), total phenol and flavonoid contents of the extract were determined. The results showed that unblanched African lettuces (AChE= 0.25 mg/ml, BChE=0.27 mg/ml) had significantly (p<0.05) higher inhibitory effect on AChE and BChE activities than blanched African lettuces (AChE= 0.34 mg/ml, BChE= 0.28 mg/ml). The result of the study revealed that blanching caused a decrease in the AChE and BChE inhibitory properties, antioxidant capacity, total phenol and total flavonoid contents of African lettuces. Therefore, the increased antioxidant and anticholinesterase properties of the unblanched African lettuce extract could be linked to its higher concentrations of the phenolic constituents compared to the blanched African lettuce.

Keywords: African lettuces, blanching, neurodegeneration, anticholinesterase