Exploring the nutraceutical potential and biological activities of Arbutus unedo L. (Ericaceae) fruits

Arbutus unedo L. fruits have a great potential to serve as an important source of biomolecules known for panoply of applications in food and pharmaceutical industry. Therefore, the chemical composition, nutraceutical properties, antioxidant power, mineral content and biological properties of ripe Arbutus unedo L. fruits were investigated. Fruits contain 10.17% carbohydrates, 0.51% lipid, 1% protein, 48 mg/100 g vitamin C, 0.2 mg/100 g alpha-tocopherols, 0.117 mg/100 g beta-tocopherols and 0.33 mg/100 g vitamin A. Fructose (57.96%) and glucose (33.87%) were the major sugars in fruits, followed by xylose (1.40%), maltose (0.51%) and sucrose (0.16%). The mineral content was 302.91 mg/100 g of Mg, 101.19 mg/100 g of Ca, 99.43 mg/100 g of K, 72.08 mg/100 g of Na, 5.11 mg/100 g of Fe, 3 mg/100 g of Zn, 0.82 mg/100 g of Cu and 0.9 mg/100 g of Mn. The liquid chromatography with photodiode array and electrospray ionisation mass spectrometric detection (LC/PDA/ESI-MS) demonstrates that the phenolic fraction was dominated by galloyl and quercetin derivatives. All extracts proved to have antioxidant activity (measured by ARTS and DPPH assays) being more significant for ethanolic one (EC50 values lower than 324.06 +/- 1.32 mu g/mL). The ethanolic extract showed a strong antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa, a moderate activity against Salmonella typhimurium, Escherichia coli, Enterococcus feacium and Candida albicans, and a poor activity against Streptocoque strain. On the basis of these results, A. unedo fruits could serve as an excellent source of high added-value phytochemicals for industrial uses.