Antioxidant capacity and identification of bioactive compounds of Myrtus communis L. extract obtained by ultrasound-assisted extraction.

Ultrasound-assisted extraction was used to investigate the polyphenolic compounds, particularly anthocyanins, present in myrtle alcoholic extracts. This type of extract is typical in the making of liqueurs obtained from herbs or plants, especially medicinal plants. The leaf extracts were found to contain flavonoids from the quercetin and myricetin families. Besides these, the berry extracts also showed the presence of anthocyanins, hydrolysable tannins and quinic acid. The antioxidant capacity was studied using the ORAC and TEAC methods and the polyphenol content was measured using the Folin-Ciocalteu method. The results showed that the values produced by the ORAC and TEAC methods were in agreement and that the antioxidant capacity correlated with the polyphenol content. The results showed that the leaf extracts exhibited higher antioxidant capacity than the berry extracts. The extraction method was easily implementable, and proved to be a swift method for obtaining bioactive compounds from vegetable matrices.

Evolution of the yields and composition of essential oil from Portuguese myrtle (Myrtus comunis L.) through the vegetative cycle.

The chemical composition of the essential oil of Portuguese myrtle was determined at different developmental stages of the plant: pre-flowering, flowering, unripe and ripe berries. The oil was extracted separately by Clevenger distillation from leaves, branches and berries. The yields vary from 0.33% to 0.74% for leaves, 0.02% to 0.19% for branches, and 0.11% to 0.23% for berries. The highest yields were obtained for the leaves in October, and for the berries in September; branches show similar values in the months of June, July and September, and the samples collected in May and October produced very little amount of oil. Altogether, September seems to be the month with the best yields for the three parts of the plant. The essential oils were analyzed by GC and GC/MS, and a total of thirty five components were identified. The major components were limonene+1,8-cineole [25.9% (berries)-39.5% (leaves)], myrtenyl acetate [6.6% (berries)-24.8% (leaves)], alpha-pinene [9.7% (berries)-21.5% (leaves)], and linalool [6.2% (leaves)-36.5% (berries)]. Portuguese myrtle belongs to the group of myrtles which are characterized by the presence of myrtenyl acetate as one of the major components.