Antioxidant Potentials and Xanthine Oxidase Inhibitory Effect of Two Furanocoumarins Isolated from Tamus communis L.

In this investigation, the screening of two furanocoumarins; 5,8- dimethoxypsoralen (1) and heraclinin (2), isolated from the methanol root-extracts of Tamus communis L for their antioxidant activity and xanthine oxidase inhibitory effect was carried out, using different assays such as DPPH free radical scavenging effect, ß- carotene / linoleic acid, xanthine oxidase (XO) inhibition and in addition to blood total antioxidant capacity. Results revealed that the two compounds have significant DPPH radical scavenging activity and effective inhibition of linoleic acid oxidation in a dose-dependent manner; 5,8-dimethoxypsoralen exhibited the highest activity with an I% = 72.69 ± 1.88%. These results indicate that the isolated compounds inhibit xanthine oxidase activity and scavenge superoxide radicals with heraclinin (2) as the more potent xanthine oxidase inhibitor, and 5,8-dimethoxypsoralen (1) as the more effective on cytochrome c reduction, the two tested compounds can effectively protect erythrocytes against hemolytic injury induced by AAPH. These results are promising for further studies of the biological and pathological effects of these natural products.

Electrospray mass spectrometry in the differentiation of some isomeric trimethylfurocoumarins.

Electrospray mass spectrometry (ES-MS) was successfully employed for the structural differentiation of six isomeric trimethylfurocoumarins of possible pharmaceutical interest. Two different approaches were employed. The first was based on MS(n) experiments of MH(+) ions. Although the product ion spectra of MH(+) of the isomers are very similar, the MS(3) spectra of the collisionally generated [MH[bond]CO](+) ions show some characteristic differences. The second approach was based on complexation of the molecules with Li(+), Na(+) and K(+) using ESI-MS of sample solutions containing alkali ions in a 100:1 molar ratio with respect to the analyte. Significant differences were observed in complex production yields, and these were related to the dimension of the alkali ion and to the steric availability of chelating groups in the different isomers.