neochrome and neoxanthin

In a previous study, we demonstrated that the carotenoid neoxanthin was contained in young leafy vegetables including spinach and showed a fat accumulation inhibitory effect in vitro. To evaluate the bioavailability of neoxanthin, a raw young spinach leaf (100 g day-1 for 4 weeks) intake test was performed on 14 participants (36.5 ± 8.0 years; male:female ratio = 9:5). Neoxanthin, neochrome, β-carotene, and lutein concentration in the spinach and blood of participants (before and after the test) was measured using high performance liquid chromatography. Neither neoxanthin nor neochrome was detected in the blood samples, whereas β-carotene and lutein concentration significantly increased (1.4- and 1.9-fold, respectively) during testing. Neoxanthin bioavailability in humans is low; thus, it is unlikely to have a fat accumulation inhibitory effect in vivo, contrary to the result in vitro. Ingesting the leafy vegetables raw can help maintain high neoxanthin levels, but it is not beneficial for neoxanthin bioavailability.

Topics: beta Carotene; Eating; Female; Humans; Lutein; Male; Spinacia oleracea; Vegetables

Developmental changes in the carotenoids and volatile compounds of Pinot noir grape berries were investigated in this study from pea size to harvest during 2012. HPLC analysis showed continued decrease of lutein, β-carotene, neochrome a and neoxanthin continued to decrease during berry development, with rapid decrease of lutein and (9'z)-neoxanthin occurred two weeks before véraison. Neochrome b and violaxanthin accumulated at early development and started to decrease two weeks before véraison. Volatile analysis demonstrated that total β-damascenone, TDN and vitispirane all increased dramatically, especially at later stage of ripening, whereas the changes for α-ionone and β-ionone were not obvious. The correlation between carotenoids and C13-norisoprenoids in the grape berries was compound-dependent, suggesting dependency on enzyme activity and specificity. In addition, C6-alcohols accumulated before véraison and decreased towards maturation, and 3-isobutyl-2-methoxyprazine decreased with increasing maturity.

Topics: Alcohols; beta Carotene; Carotenoids; Chromatography, High Pressure Liquid; Fruit; Lutein; Norisoprenoids; Taste; Vitis; Volatile Organic Compounds; Wine; Xanthophylls

Neoxanthin, a major carotenoid in green leafy vegetables, was reported to exhibit potent antiproliferative effect via apoptosis induction on human prostate cancer cells. However, the metabolic fate of dietary neoxanthin in mammals remains unknown. In the present study, we investigated the gastrointestinal metabolism of neoxanthin in mice and the in vitro digestion of spinach, and estimated the antiproliferative effect of neoxanthin metabolites on PC-3 human prostate cancer cells. Two hours after the oral administration to mice of purified neoxanthin, unchanged neoxanthin and stereoisomers of neochrome (8'-R/S) were detected in the plasma, liver, and small intestinal contents. To estimate the effect of intragastric acidity on the conversion of dietary neoxanthin into neochrome (epoxide-furanoid rearrangement), spinach was digested in vitro by incubating it with a pepsin-HCl solution at pH 2.0 or 3.0 (gastric phase) followed by a pancreatin-bile salt solution (intestinal phase). Spinach neoxanthin was largely converted into (R/S)-neochrome during the digestion when the gastric phase was set at pH 2.0, whereas the rearrangement was observed to a lesser extent at pH 3.0. (R/S)-neochrome dose-dependently inhibited the proliferation of PC-3 cells as well as neoxanthin at concentrations < or = 20 micromol/L. Although neoxanthin induced evident apoptotic cell death, (R/S)-neochrome inhibited the cell proliferation without obvious apoptosis induction. These results indicate that dietary neoxanthin is partially converted into (R/S)-neochrome by intragastric acidity before intestinal absorption and that (R/S)-neochrome exhibits an antiproliferative effect on PC-3 cells by the induction of cytostasis.

Topics: Animals; Antineoplastic Agents; Cell Division; Cell Line, Tumor; Digestion; Epoxy Compounds; Gastric Acid; Gastrointestinal Tract; Humans; Isomerism; Male; Mice; Mice, Inbred ICR; Prostatic Neoplasms; Spinacia oleracea; Xanthophylls