Antioxidant activity of selected wild Canadian prairie fruits.

BACKGROUND: Canadian prairies are a habitat for unique wild plants. The main object of the present study was to investigate phytochemicals content and antioxidant activity in seven wild Canadian prairie fruits. METHODS: The presence of total phenolics, flavonoids, anthocyanins and antioxidant activity were identified in the extracts according to standard procedure. RESULTS: Wild rose had the highest amounts of total phenolics and total flavonoids, whereas elderberry exhibited the highest amount of anthocyanins. All extracts showed good scavenging activities towards DPPH radicals. The results showed a good linear relationship between oxygen radical absorbance capacity and total phenolics indicating that radicals are scavenged at a greater rate as the total phenolics content increases. Additionally, all extracts when applied at concentration of 800 ppm, showed ability to inhibit oxidation of canola oil. In SOT test the best results were obtained when extract of American mountain ash was used. In general, wild rose followed by American mountain ash demonstrated the highest antioxidant activity among assessed Canadian prairie fruits. CONCLUSIONS: From the results it can be concluded that prairie fruit extracts are a rich source of phenolic compounds and poses a high antioxidant activity, confirmed by assessment with different type of radicals employed.

Proteomic analysis of up-accumulated proteins associated with fruit quality during autumn olive (Elaeagnus umbellata) fruit ripening.

Fruit ripening is a complex phenomenon that makes berries attractive and also determines their nutritional value. Autumn olive ( Elaeagnus umbellata Thunb.) fruit is a rich source of many human health-related nutrients. The changes in pericarp color are initiated at early developmental stages, coinciding with the fast increase in fruit size. Fruit quality traits with special emphasis on soluble sugars, organic acids, lycopene, and total protein contents were assayed during the fruit ripening. In the fully ripe fruit, glucose and fructose were the principal sugars, malic acid was the most abundant organic acid, and lycopene concentration was extremely high. A proteomic analysis was used to identify up-accumulated proteins induced by the ripening. Among 63 up-accumulated protein spots, 43 were successfully identified by MALDI-TOF/TOF-MS. All 43 proteins were novel for autumn olive, and 8 were first reported in the fruit. Twenty-one proteins of known function were involved in sugar metabolism, citric acid cycle, isoprenoid metabolism, fatty acid synthesis, and protein hydrolysis. The possible roles of these 21 accumulated proteins in autumn olive fruit quality are discussed.