Myrtle (Myrtus communis L.) berries: composition and properties

Myrtle (Myrtus communis L.) berries are very popular fruits in the Mediterranean area. They are used for food aromatization and for the preparation of characteristic alcoholic products such as liqueur, eau-de-vie and wine. The berries are spherical in shape, dark red to violet in color, and contain organic acids, carbohydrates, phenolic compounds, volatiles, lipids, anions and cations. Their distinctive flavor and color are due to their volatiles and polyphenols content, respectively. The main compounds in myrtle berries’ volatile fraction are -pinene, limonene and 1,8-cineole. The phenolic compounds fraction is characterized by gallic acid, flavonoids and anthocyans that represent the most abundant phytochemicals in myrtle berries. The anthocyanin profile shows five anthocyanin glucosides and four anthocyanin arabinosides with malvidin-3-O-glucoside, delphinidin-3-O-glucoside, and petunidin-3-O-glucoside as major peaks. Flavonoid profile is characterized by myricetin-3-O-galactoside, myricetin-3-O-rhamnoside, myricetin and quercetin. Myricetin and gallic acid derivatives are thought to be the most efficient molecules in inhibiting free radical and lipid peroxidation. Myrtle berry extracts prepared using solvents with different polarity (water, ethanol, and ethyl acetate) were analyzed using several in vitro tests to investigate their antioxidant properties. The strongest antiradical and antioxidant activities (measured with DPPH and FRAP tests, respectively) were found in ethanol and ethyl acetate extracts. These same extracts also showed the highest content of phenolic compounds. The ethyl acetate extract had the strongest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu2+-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that besides the well-established food use, myrtle berries could be used in dietary supplement preparation or as food additives. Therefore, because of their multiple possible uses, a cultivar selection programme has been recently started with the aim of providing berries with the best nutritional properties for industrial use.