Antioxidant activities of two commercial spices, Myristica fragrans (HOUTT, nutmeg) and Pimenta dioica (L., allspice), were analyzed for the first time in a hemin-enhanced oxidation (HET) assay. Hemin is a potentially cytotoxic factor that can act as an efficient prooxidant. Relative activities of the two spices were compared in HET and other assays. When standardized for total phenolic content (mg gallic acid equivalents, GAE), ethanolic and aqueous Myristica extracts had 4- and 10-fold greater activity relative to Pimenta (p < 0.05). Myristica also had a 3-fold greater aqueous:ethanolic activity ratio compared to Pimenta. Our results (a) provide novel evidence for potent Myristica antioxidants, especially water- soluble ones, in HET assays, and (b) provide a basis for further testing of Myristica phytochemicals in heme-related pathological models. Most other reported protocols also indicate a higher Myristica potency relative to Pimenta, with standardized relative antioxidant activity variations up to 27-fold. Such variation, as well as the distinct reactive species implicated in some pathologies, emphasize the importance of comparing multiple assays to evaluate antioxidant activities.
Keywords: Antioxidant activities, food spices, hemin, Myristica fragrans, Pimenta dioica, total phenolic content.