Analysis of Food-based Antioxidants

Pumpkin seeds supply 1170 mg phosphorus and 800 mg potassium per 100 g dried weight

Sunflower seeds contain phytosterols (534 mg), niacin (8.3 mg) and manganese (2 mg) per 100 g dried weight

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Phytochemistry

Certain molecular structures have been associated with radical quenching activity. In polyphenol moieties, 3',4'- dihydroxy groups substituted in the B ring and conjugation between the A and B rings, e.g. quercetin, confers antioxidant capacity four times that of the standard vitamin E analogue, Trolox. 1

Quercetin See also potency of quercetin glycosides >>>> Antioxidant potencies

By way of contrast, the epicatechin structure which lacks the conjugation through the C ring but still has a (4',5'-) dihydroxy structure, has only 50% of the activity of quercetin.

Epicatechin

Similarly, kaempferol which lacks the dihydroxy structure in the B ring but still has conjugation through the A and B rings, also retains about 50% of the activity of quercetin. Both kaempferol and epicatechin still have more activity than vitamin C, and these theoretical observations agree, in the case of epicatechin, with the experimental data on apples. Go to >>>> Antioxidant potencies

Kaempferol

References 1. C.A. Rice-Evans et al., Free Radic. Res. (1995), (4) 375-383. Permission to reprint granted by Taylor and Francis.

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