Food Chemistry 119 (2010) 1300–1306
To evaluate the nutritional advantages of quinoa seeds (Chenopodium quinoa Willd.) cultivated in Japan,
antioxidative properties and flavonoid composition were determined and compared to corresponding
data for conventionally-used cereals and pseudo-cereals, including quinoa seeds from South America.
The antioxidant activities of these grains against DPPH radicals were strongly associated with the total
phenolic content of the tested samples. The crude extracts of quinoa seeds cultivated in Japan exhibited
higher antioxidative effects than those from South America and other cereals, excluding buckwheat. Four
flavonol glycosides were isolated and identified from the Japanese quinoa seeds, and the chemical composition
of the flavonoids – quercetin and kaempferol 3-O-(200,600-di-O-a-rhamnopyranosyl)-b-galactopyranosides
(1 and 4), quercetin 3-O-(200,600-di-O-a-rhamnopyranosyl)-b-glucopyranoside (2), and
quercetin 3-O-(200-O-b-apiofuranosyl-600-O-a-rhamnopyranosyl)-b-galactopyranoside (3) – was evaluated
through quantitative determination. Trioside 2 was isolated for the first time from quinoa seeds. These
glycosides were not detected in extracts from any of the tested grains except quinoa. The aglycone quercetin
content of the Japanese quinoa seeds is higher than in the seeds from South America and buckwheat.
The amounts of quercetin and kaempferol formed via acidic hydrolysis in quinoa are much
higher than those of conventionally-used edible plants. The quinoa seeds cultivated in Japan are the most
effective functional foodstuff – in terms of being a source of antioxidative and bioactive flavonoids –
among cereals and pseudo-cereals.