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The treatment of neurological disorders and neurodegenerative diseases is related to the levels of acetylcholine (ACh) through the inhibition of acetylcholinesterase (AChE). Galanthamine, an important alkaloid isolated from the Amaryllidaceae family, is approved for the pharmacological treatment of Alzheimer's disease (AD) and acts by inhibiting the acetylcholinesterase (AChE) activity. In the present study, Ellman's method was used to verify the inhibition of AChE activity of some isoquinolines alkaloids such as galanthamine, montanine, hippeastrine and pretazettine. At the concentrations 1mM, 500 microm and 100 microm, galanthamine presented an AChE inhibition higher than 90%. Montanine inhibited, in a dose-dependent manner, more than 50% of the enzyme at 1mM concentration. With the concentrations 500 microm and 100 microm, 30-45% of AChE activity inhibition was detected. The alkaloids hippeastrine and pretazettine presented no significant inhibition of the AChE activity. The results demonstrate that montanine significantly inhibits AChE activity at the tested concentrations, suggesting the necessity of further investigations on this alkaloid use in treating neurological disorders., ((c) 2009 Elsevier GmbH. All rights reserved.)

The dichloromethane and n-butanol extracts obtained from fresh bulbs of Hippeastrum vittatum (Amaryllidaceae), collected in Southern Brazil, were evaluated for their cytotoxic activity in vitro against five human cell lines (HT29 colon adenocarcinoma, H460 non-small cell lung carcinoma, RXF393 renal cell carcinoma, MCF7 breast cancer, and OVCAR3 epithelial ovarian cancer), using the sulphorhodamine B assay. Both extracts showed potential antiproliferative activity. From CH(2)Cl(2) fraction, three alkaloids were isolated: lycorine, vittatine and montanine. The two last compounds were submitted to the antiproliferative assay and the highest level of cytotoxicity was found for the alkaloid montanine.