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Radical scavenging activity of Alkanna tinctoria root extracts and their main constituents, hydroxynaphthoquinones
Author(s) -
Assimopoulou A. N.,
Papageorgiou V. P.
Publication year - 2005
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.1645
Subject(s) - scavenging , chemistry , dpph , moiety , monomer , biological activity , organic chemistry , naphthoquinone , hydroxyl radical , antioxidant , biochemistry , polymer , in vitro
Abstract Alkannin and shikonin (A[sol ]S) are pharmaceutical substances with a wide spectrum of biological properties. Radical scavenging activity is involved in aging processes, antiinßammatory, anticancer and wound healing activities. Hence, in the present study the DPPH radical scavenging activity of alkannin and shikonin, both monomeric and oligomeric, and extracts of Alkanna tinctoria roots were studied and a structure–activity relationship was approximated. It was shown that both monomeric and oligomeric alkannin and shikonin and also A[sol ]S esters exhibited extremely high radical scavenging activity. The presence of the naphthoquinone moiety seems to be essential for that activity, while the side chain of A[sol ]S possibly plays a minor role. Esterification of A[sol ]S on the side chain hydroxyl group does not affect radical scavenging activity. Organic solvents and olive oil (extracted at room temperature) extracts of Alkanna tinctoria roots, which contain as active ingredients A[sol ]S esters, exhibited very good antiradical activity. Alkannin and shikonin and their esters and also extracts of Alkanna tinctoria roots could be used promisingly in pharmaceutical and cosmetic preparations for their radical scavenging activity and probably for their antiaging activity. Copyright © 2005 John Wiley & Sons, Ltd.