ABSTRACT
Air-induced paper discoloration is described as being different from other discoloration morphologies. It seems to be the result of prolonged exposure to air in a humid and polluted environment without appropriate protecting coverage. In this work, three folios from the same eighteenth century book, presenting three degrees of discoloration and opacity and subjected to different environmental conditions, were examined and compared. Samples were analyzed and compared by three different instrumental techniques, mid-infrared spectroscopy, X-ray fluorescence (XRF), and scanning electron microscopy (SEM). Chemical and physical changes were confirmed from the data collected by these techniques. The absence of the secondary amide band characteristic of proteins in the infrared spectra of the two discolored folios, accompanied by the appearance and increase of white mineral-like deposits visible in the SEM micrographs, support the idea that oxidation reactions occurred and that these two folios were subjected to more severe degradation hazard.
ABSTRACT
Hesperidin (Hp), a citrus flavonoid predominantly found in oranges, shows bone-sparing effects in ovariectomised (OVX) animals. In human subjects, the bioavailability of Hp can be improved by the removal of the rhamnose group to yield hesperetin-7-glucoside (H-7-glc). The aim of the present work was to test whether H-7-glc was more bioavailable and therefore more effective than Hp in the prevention of bone loss in the OVX rat. Adult 6-month-old female Wistar rats were sham operated or OVX, then pair fed for 90 d a casein-based diet supplemented or not with freeze-dried orange juice enriched with Hp or H-7-glc at two dose equivalents of the hesperetin aglycone (0.25 and 0.5 %). In the rats fed 0.5 %, a reduction in OVX-induced bone loss was observed regarding total bone mineral density (BMD):+7.0 % in OVX rats treated with Hp (HpOVX) and +6.6 % in OVX rats treated with H-7-glc (H-7-glcOVX) v. OVX controls (P < 0.05). In the rats fed 0.25 % hesperetin equivalents, the H-7-glcOVX group showed a 6.6 % improvement in total femoral BMD v. the OVX controls (P < 0.05), whereas the Hp diet had no effect at this dose. The BMD of rats fed 0.25 % H-7-glc was equal to that of those given 0.5 % Hp, but was not further increased at 0.5 % H-7-glc. Plasma hesperetin levels and relative urinary excretion were significantly enhanced in the H-7-glc v. Hp groups, and the metabolite profile showed the absence of eriodictyol metabolites and increased levels of hesperetin sulphates. Taken together, improved bioavailability of H-7-glc may explain the more efficient bone protection of this compound.