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Download fileEffect of Benzylic Oxygen on the Antioxidant Activity of Phenolic Lignans
journal contribution
posted on 28.10.2005, 00:00 authored by Satoshi Yamauchi, Yoshimasa Hayashi, Yuki Nakashima, Takuya Kirikihira, Kazuki Yamada, Toshiya MasudaIt has been clarified in the present investigation that a high degree of oxidation at the benzylic position
of phenolic lignans bearing a 4-hydroxy-3-methoxybenzyl group reduces their antioxidant activity and
that the antioxidant activity of the bis(4-hydroxy-3-methoxybenzyl)tetrahydrofuran lignan 2 is higher
than that of the corresponding γ-butyrolactone lignan 1. This was demonstrated by comparing the
antioxidant activities of compounds 1 and 2 with those of the (benzyl)(hydroxybenzyl)tetrahydrofurans
3 and 4, the bis(hydroxybenzyl)tetrahydrofurans 7 and 8, the (benzoyl)(benzyl)tetrahydrofuran 6, and
the dibenzoyltetrahydrofuran 9. The activity level of compound 2 was approximately the same potency
as that of the tetrahydronaphthalene-tetrahydrofuran 5. These compounds possess either a 4-hydroxy-3-methoxybenzyl group or a 4-hydroxy-3-methoxybenzoyl group as the benzyl or benzoyl group. An
examination of radical scavenging activity showed differences of activity between diastereomers. To make
this comparison possible, compounds 1−9 were synthesized using new synthetic routes for several of
these lignans. In this investigation, stereoisomers of the (benzyl)(hydroxybenzyl)tetrahydrofurans 3 and
4 and liovils 7 and 8 were synthesized for the first time.