assessment of antioxidant, neuroprotective, anti-urease and anti-tyrosinase capacities of leaves extracts.

Abstract

Objective: To characterize the chemical profile of methanolic crude extract and its fractions (Ethyl acetate, n-butanol and aqueous) using liquid chromatography-mass spectrometry (LC-MS) analysis, to evaluate their biological and pharmacological properties: antioxidant (1, 1-diphenyl-2-pycrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic) (ABTS), galvinoxyle free radical scavenging, reducing power, phenanthroline and β carotene-linoleic acid bleaching assays), enzymes inhibitory ability against several enzymes [acetyl-cholinesterase (AChE), buthyrylcholinesterase (BChE), urease and tyrosinase].

Methods: Secondary metabolites were extracted from Tamarix africana air-dried powdered leaves by maceration, the crude extract was fractionated using different solvents with different polarities (Ethyl acetate, n-butanol and aqueous). The amount of polyphenols, flavonoids and tannins (hydrolysable and condensed) were determined using colorimetric assays. A variety of biochemical tests were carried out to assess antioxidant and oxygen radical scavenging properties using DPPH, ABTS, galvinoxyle free radical scavenging, reducing power, phenanthroline and β carotene-linoleic acid bleaching methods. Neuroprotective effect was examined against acetylcholinesterase and buthy-rylcholinesterase enzymes. The anti-urease and anti-tyrosinase activities were performed against urease and tyrosinase enzymes respectively. The extract's components were identified using LC-MS and compared to reference substances.

Results: The results indicated that Tamarix africana extracts presented a powerful antioxidant activity in all assays and exhibited a potent inhibitory effect against AChE and BChE as well as urease and tyrosinase enzymes. LC-MS analysis identified amount of eight phenolic compounds were revealed in this analysis; Apigenin, Diosmin, Quercetin, Quercetine-3-glycoside, Apigenin 7-O glycoside, Rutin, Neohesperidin and Wogonin in methanolic extract and its different fractions of Tamarix africana from leaves.

Conclusions: Based on these findings, it is reasonable to assume that Tamarix africana could be considered as a potential candidate for pharmaceutical, cosmetics, and food industries to create innovative health-promoting drugs.