Antiradical and antioxidant activities of alkaloids isolated from Mahonia aquifolium. Structural aspects.
The antioxidant activities of three alkaloids isolated from Mahonia aquifolium--berberine, jatrorrhizine, and magnoflorine--were studied with respect to their structural aspects, particularly the presence and the position of -OH groups, steric conditions of unpaired electron delocalization and parameters of lipophilicity and hydration energy. The antiradical activities of the compounds tested were evaluated as the reactivities toward free stable alpha,alpha'-diphenyl-beta-picrylhydrazyl radical (DPPH). The antioxidant features of the alkaloids tested were investigated in heterogeneous membrane system of DOPC liposomes stressed by peroxidative damage induced by AAPH azoinitiator. Both alkaloids bearing free phenolic groups--jatrorrhizine and magnoflorine--showed better activities in both systems used than berberine not bearing any readily abstractable hydrogen on its skeleton. The former two showed antiperoxidative efficiency in DOPC liposomal membrane comparable to that of an effective scavenger of peroxyl radicals--stobadine-and higher than that of Trolox. We conclude that the favorable antioxidant features of the hydroxylated alkaloids are most probably ensured by the combination of reasonably high antiradical reactivity with high lipophilicity, however, the solvation process was found to markedly interfere with these beneficial effects.
Racková
Lucia
L
Institute of Experimental Pharmacology, Slovak Academy of Sciences, Dúbravská str. 9, SK-841 04 Bratislava, Slovak Republic. exfadada@savba.sk
Májeková
Magdaléna
M
Kost'álová
Daniela
D
Stefek
Milan
M
D000470:Alkaloids / Q000302:isolation & purification* / Q000494:pharmacology; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D002243:Carbolines / Q000494:pharmacology; D006859:Hydrogen / Q000737:chemistry; D006900:Hydroxylation; D015227:Lipid Peroxidation / Q000187:drug effects*; D008081:Liposomes / Q000378:metabolism; D028143:Mahonia / Q000737:chemistry*; D003904:Mitosporic Fungi / Q000187:drug effects; D010636:Phenols / Q000737:chemistry; D010713:Phosphatidylcholines / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry; D013329:Structure-Activity Relationship; D013997:Time Factors
D000470:Alkaloids; D000975:Antioxidants; D002243:Carbolines; D008081:Liposomes; D010636:Phenols; D010713:Phosphatidylcholines; D010936:Plant Extracts; C042329:phenoxy radical; D006859:Hydrogen; C017251:1,2-oleoylphosphatidylcholine; C100106:dicarbine