217 - Biological Studies on Alnus Orientalis Var. pubescens Dippel Leaves

Abstract

Alnus Miller (Betulaceae) comprises 35 species which is widely distributed in the temperate regions of the northern hemisphere, also is represented by six taxa in Turkey. Traditionally, Alnus s pecies are used for the treatment of rheumatism, hemorrhoids, dental abscess, nail inflammation and various skin diseases such as chronic herpes, eczema, prurigo, hepatitis, inflammation of uterus, dysentery, stomachache, diarrhea, fever etc. The aim of the present work is to evaluate the antioxidant and some enzymatic activities such as acetylcholinesterase (ACE), butyrylcholinesterase (BCE), cyclooxygenase COX-1 and COX-2, and also monoamine oxidase MAO-A and MAO-B inhibitory effects of the methanol and ethyl acetate extracts from Alnus orientalis var. pubescens Dippel. leaves. The results were compared with that of BHT, ascorbic acid, Trolox and EDTA. The total phenolic contents of the studied extracts were determined by Folin-Ciocalteu assay. The methanol and ethyl acetate extracts of A. orientalis showed moderate ABTS radical cation decolorization activity with inhibitions of 54.55% and 44.81% respectively when compared to Trolox (79.01%) at 0.5 mg/mL. Both methanol and ethyl acetate extracts showed significant ferric-reducing power with EC 50 values of 0.26 and 0.38 respectively comparable to BHT (EC 50 = 0.2). Also according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity results, the methanol extract is more effective (30.54±0.2 inhibition %) than the ethyl acetate extract (16.40±0,9 inhibition %) when compared to BHT (48.31±1.04 %) and ascorbic acid (74.00±1.4 %) at 0.0036 µg/mL. The methanol extract exhibited significant inhibitory effects 56.35 %, 55.00% on the ACE and COX-1 enzymes respectively when the ethyl acetate extract showed very strong inhibitory effect on only COX-1 enzyme with 74.74 % inhibition at 250 µg/mL. A. orientalis methanol extract had higher total phenolic content (240.14 mg gallic acid equivalent (GAE)/100 g) than the ethyl acetate extract (203.13 mg GAE/100 g plant).