Quercetin levels high in Mauritian vegetables

Further evidence to support the antioxidant power of broccoli and cabbage revealed this week following a small investigation into the phenol and flavonoid levels of ten common vegetables.

In a small study between an Indian island and a London university, scientists conclude that Mauriitan vegetables represent a significant source of phenolic antioxidants.

"Quercetin derivatives were the most abundant, and this may contribute to their potential health benefits," report the researchers this week in the September issue of Journal of the Science of Food and Agriculture.

A raft of recent science has uncovered the role polyphenols, to which quercetin belongs, can play in preventing the onset of various diseases, notably certain cancers and cardiovascular disease, that annually kills 17 million people in the world.

"Quercetin was the dominant flavonoid aglycone in the hydrolysed vegetable extracts, with values in the range of 15-390 µg g-1 fresh weight," say the researchers from the Imperial College London, the University of Mauritius and the University of Glasgow.

They analysed ten Mauritian vegetables - broccoli, cauliflower, white cabbage, lettuce, Chinese cabbage, mugwort, carrot, onion, tomato and chilli pepper - for their total phenol, flavonoid, proanthocyanidin and vitamin C contents and antioxidant capacity.

Levels of total phenols in the vegetables varied quite considerably, between 132 and 1189 µg g-1 fresh weight and those of total flavonoids between 45 and 944 µg g-1, write the scientists.

Vitamin C also varied considerably, between 25 and 748 µg g-1 fresh weight while the antioxidant compounds, proanthocyanidins, were detected at very low levels in only a few vegetables.

Proanthocyanidins have been linked to helping to prevent disease-causing organisms from causing infection.

"Mauritian vegetables therefore represent a significant source of phenolic antioxidants," conclude the scientists.

Full findings are published in the Journal of the Science of Food and Agriculture September 2004, vol. 84, no. 12, pp. 1553-1561(9).