Phenological Variations in Essential Oil Composition and Phytochemical Characteristics of Myrtus communis L.

Myrtle (Myrtus communis L.) is an important medicinal plant, with all parts have pharmaceutical and nutritional applications and it is distributed throughout the southwest regions of Iran. Furthermore, acknowledging the importance of medicinal compounds, flavonoids, and phenolic acids in plants and human health, understanding the optimal harvest time for maximum biological activity, which can be therapeutic, and predicting and controlling the quality of medicinal plants are essential. Therefore, we aimed to determine the effects of the different phenological stages on the volatile constituents, antioxidant activity and phytochemical characteristics of the myrtle. Essential oil obtained by hydro distillation was characterized by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). In this study, five replications were considered for all factors, following a completely randomized design. The radical scavenging activity of the stable DPPH free radical was used to determine the antioxidant activity of the plant extract, according to standard methods. Flavonoid, total phenol and some phenolic compounds including gallic acid, caffeic acid, vanillin, p-coumaric acid and catechin were detected and quantified in the Myrtus communis extracts. The predominant natural components were α-Pinene, Butyl propanoate, 1,8-Cineole, linalool and α-terpineol, which showed their highest amounts at the vegetative stage. linalyl acetate, p-cymene, and limonene had the highest concentrations at the full flowering stage. The highest concentrations of total flavonoids, percentage of essential oil, caffeic acid, vanillin and antioxidant activity were observed at full flowering stage. On the other hand, the highest total phenol, p-coumaric acid and catechin content was observed at vegetative growth. In conclusion, this investigation provides beneficial evidence about the most appropriate harvest time for myrtle to produce the most favorable constituents for optimization in food, pharmaceutical, and herbal products.