In this study, the antioxidant and antiacetylcholinesterase activities of Sorbus torminalis (L.) Crantz fruits were evaluated. Total phenolic and flavonoid compounds, 2,2'-azino-bis (3-ethylbenzothioazoline-6-sulfonic acid), 2,2'-diphenyl-1-picrylhydrazyl, and superoxide anion radicals scavenging activities and ferric-reducing antioxidant power of water, ethyl acetate, acetone, and methanol extracts were determined for the measurement of the antioxidant activity. Quercetin and α-tocopherol were used as standard antioxidants. The inhibitory effect of the water extract on acetylcholinesterase (AChE) was evaluated using the Ellman method and galantamine was used as a standard. Water extract had the highest total phenolic concentration and the strongest antioxidant activity followed by ethyl acetate and acetone extracts whereas methanol extract has the lowest phenolics and weakest antioxidant activity. Moreover, water extract showed moderate ability to inhibit AChE. It was concluded that fruits of S. torminalis have antioxidant and anti-AChE activities and that the plant might be a natural source of antioxidants and AChE inhibitors.

Fruits of several Sorbus species (Rosaceace) are used both in traditional medicine as antidiabetic, antiinflammatory, diuretic, vasoprotective and in foods. In this study, in vitro antidiabetic activities of water extracts of Sorbus aucuparia L. (rowan tree) and Sorbus torminalis L. Crantz (wild sevice tree) fruits were investigated by measuring inhibitory potentials on α-glucosidase and pancreatic α-amylase activities, the most important digestive enzymes. Also, the total phenolic and flavonoid contents of the fruits were determined to evaluate the association between phenolic content and antidiabetic activity. S. torminalis and S. aucuparia extracts exhibited strong α-glucosidase inhibitory activity, more effective than that of standard drug acarbose. However, S. torminalis has shown moderate inhibitory effect against α-amylase while S. aucuparia exhibited weak inhibition. The total phenolic and flavonoid contents of the fruits were correlated with andiabetic activities. It has been suggested that antidiabetic effects of the fruits may be due to phenolic compounds present therein. Therefore, S. aucuparia and S. torminalis fruits might be potential sources of antidiabetic compounds.

The role of acetylcholinesterase in terminating acetylcholine-mediated neurotransmission made it the focus of intense research. In this study the haemolymph Acetylcholinesterase (AChE) from the mollusc Mytilus galloprovincialis was purified to homogeneity by (NH4)2SO4 fractional precipitation and affinity chromatography on edrophonium-Sepharose 6B. The enzyme was purified approximatedly 13 fold over the crude extract and was obtained in 3 % yield. The specific activity of purified enzyme was 3 U/mg protein. It had an optimum pH of 7.5 and showed optimal activity at 35 o C. Km and Vmax for acetylthiocholine iodide were 1.3 mM and 0.188 mM/mg/min, respectively. The purified enzyme migrated as a 51 000 dalton band during polyacrylamide gel electrophoresis under denaturing and reducing conditions. Three methoxyflavones were examined in order to evaluate their potential as anti-Alzheimer's Disease (AD) agents. All of the compounds were shown to be potent AChE inhibitors. Therefore, these compounds may have great value in the development of therapeutic and preventive agents for AD.

INTRODUCTIONThioredoxin (Trx), nicotinamide adenine dinucleotide phosphate (NADPH) and thioredoxin reductase (TrxR) comprise a thioredoxin system which exists in nearly all living cells (Arnér and Holmgren 2006). Trx, the physiological substrate for TrxR, occurs in either an oxidized or a reduced form. Reduced Trx prevents oxidation of various proteins by donating hydrogen atoms from two of the cysteine residues at its active site. Oxidized Trx is reduced by TrxR using NADPH as an electron donor (Seo and Lee 2010).TrxR belongs to the pyridine nucleotide-disulfide oxidoreductase family and is a dimeric flavoenzyme (Lu et al. 2009). The preliminary purification and characterization studies were performed with TrxR from archaea, bacteria and anaerobic amino-acid-utilizing bacteria (