Influence of Organic and Chemical Fertilisation on Antioxidant Compounds Profiles and Activities in Fruits of Fragaria ananassa var. Camarosa
Non-communicable diseases (NCDs) present a long duration and a slow progression. Good nutrition plays a predominant role in NCD prevention. In Chile, the cultivation of strawberry (Fragaria ananassa) has recently been adapted to volcanic soils with low available phosphorus (P), which can affect the fruit quality in terms of their antioxidant compound content and anti-inflammatory activities. Here, we carried out a study using organic (OF) or chemical (TF) fertilisers at 50 and 100% of the agronomical dose recommendation and without fertilisation (WF) under field conditions. Identification of phenolic compounds was done by HPLC-DAD-ESI-MS/MS, whereas antioxidant activities were determined by spectrophotometric methods. The highest concentrations of anthocyanins and ascorbic acid were obtained in the OF treatments, showing a relationship with the CUPRAC (cupric reducing antioxidant capacity) values. The highest concentrations of total polyphenols were obtained in the TF treatments, according to the TEAC (Trolox equivalent antioxidant capacity), CUPRAC and 2,2-diphenyl-1-picrylhydrazyl tests. The highest enzymatic activities were observed also in the TF treatments. Compared with WF, TF treatment downregulates the cytokine interleukin 10 (IL-10) significantly at a dose of 100%, but we could not show a significantly downregulation yet. Our results suggest that enzymatic antioxidant activity responds better to a period of prolonged exposure to P fertilisation. There is no direct correlation between enzymatic and non-enzymatic antioxidant activity with respect to treatments with different types of P fertilisation.