N. Russo et al., Semiempirical molecular modeling into quercetin reactive site: Structural,conformational, and electronic features, J AGR FOOD, 48(8), 2000, pp. 3232-3237
The conformational behavior, molecular geometry and electronic structure of
quercetin were investigated using the semiempirical AM1 and PM3 methods. R
esults reveal that quercetin has a nonplanar molecular structure, with cros
s-conjugation occurring at the C ring. Calculations were also performed for
quercetin radical species at the OH groups, showing the presence of three
radicals in a narrow range of energy. An interpretation of the antioxidativ
e process mechanism, exerted by quercetin as a free radical scavenger, reli
es on two isoenergetic radicals with extended electronic delocalization bet
ween adjacent rings, also having cross-conjugated systems and being affecte
d by the experimental environment influencing their relative order.