Biological activity of strawberry tree fruit

The strawberry tree (Arbutus unedo L.) is one of the most common species with fleshy fruits in the Mediterranean region [1]. In local agricultural communities, the mealy and sweetish but not very aromatic fruits are mainly used for the production of jams, marmalades and alcoholic beverages. Also, the chemical composition indicates that the fruits are a good source of minerals and have high content of phenols and antioxidant capacity [2]. The aim of our work was to investigate the antioxidant and cytotoxic potential of A. unedo fruits on human squamous cell carcinoma cell line (CAL 27), human gastric adenocarcinoma cell line (AGS), colorectal adenocarcinoma cell line (Caco-2) and hepatocellular carcinoma cell line (HepG2). Furthermore, the DNA-protective effect and antimicrobial activity against Escherichia coli were investigated. A concentration range of 0.01-100 mg/mL was used in the experiments, with 1 mg/mL and 10 mg/mL being the recommended daily dose of polyphenols based on human blood volume and average human weight, respectively. Strawberry tree fruits at the recommended daily doses had a proliferative effect on AGS and CAL 27 cells without recovery and with 24-hour cell recovery, respectively. In CAL 27 cells, antioxidant activity was shown during 24-hour cell recovery. In Caco-2 and HepG2 cells, A. unedo fruit was shown to induce reactive oxygen species (ROS). The concentrations tested showed no antimicrobial activity against E. coli, but a dose-dependent protective effect on DNA was demonstrated. Additionally, further studies on individual bioactive compounds from strawberry tree fruit are needed to provide more detailed information on their potential use.