Biologically active alkaloids and a free radical scavenger from Prosopis species

The biological activity of extracts from the aerial parts of five Argentini an Prosopis species and the exudate of P. flexuosa were assessed for DNA bi nding, beta-glucosidase inhibition and free radical scavenging effect using the DPPH decoloration assay. DNA binding effect was found mainly in the ba sic fraction. The alkaloids tryptamine as well as piperidine and phenethyla mine derivatives were isolated from the basic extracts. At 0.50 mg/ml, DNA binding activities ranged from 28% for tryptamine to 0-27% for the phenethy lamine and 47-54% for the piperidine derivatives. Tryptamine and 2-beta-met hyl-3-beta-hydroxy-6-beta-piperidinedodecanol showed a moderate inhibition (27-32%) of the enzyme beta-glucosidase at 100 mu g/ml. The exudate of P. f lexuosa displayed a strong free radical scavenger effect in the DPPH decolo ration assay. The main active constituent was identified as catechin. (C) 2 000 Elsevier Science Ireland Ltd. All rights reserved.