Question

Beneficial health effects of many "berries" are mainly due to:

alkaloids

antioxidants

cyanogenic glycosides

polysaccharides

Answer 1

ANS: Antioxidants

Berries are a rich source of sugars(glucose, fructose) and dietary fiber(cellulose, hemicellulose, pectin). Though, low in calories they also contain natural antioxidants such as vitamins C(ascorbic acid) and E, and micronutrients such as folic acid, calcium, selenium, alpha, and beta carotene, lutein and organic acids, such as citric acid, malic acid, tartaric, oxalic and fumaric acid. However, the health benefits of berries are mainly associated with the presence of bioactive compounds associated with the antioxidant properties which also include flavonoids (importantly anthocyanins) and ellagitannins among other phenolic compounds. The antioxidants have been studied in preventing inflammation disorders, cardiovascular diseases, and in protective effects to lowering the risk of various cancers through the potential interactions in the mechanisms including counteracting free radical generation, attenuating inflammatory gene expression, downregulating foam cell formation, and upregulating eNOS expression.

source:

[1]   S. Skrovankova, D. Sumczynski, J. Mlcek, T. Jurikova, and J. Sochor, “Bioactive compounds and antioxidant activity in different types of berries,” International Journal of Molecular Sciences. 2015.
[2]   A. Basu, M. Rhone, and T. J. Lyons, “Berries: Emerging impact on cardiovascular health,” Nutrition Reviews. 2010.

* cyanogenic glycosides are plant toxins also found in some fruits.