Psidium myrtoides O. Berg fruit and leaves: physicochemical characteristics, antifungal activity and chemical composition of their essential oils in different seasons

This paper aims to investigate, for the first time, physicochemical characteristics and antioxidant capacity of Psidium myrtoides ripe and unripe fruit. In addition, essential oil was extracted from fresh leaves (PM-EO) collected in dry and rainy seasons to investigate the influence of seasonality and, after that, to evaluate its antifungal activity on mycelial growth of Colletotrichum gloeosporioides. Both GC-FID and GC-MS analyses revealed that major components determined in PM-EO were β-caryophyllene (20.0% and 32.9%) and limonene (10.4% and 19.8%) in rainy and dry seasons, respectively. High antioxidant capacity was displayed by unripe fruit (IC50 = 3.57 mg/mL) and ripe ones (IC50 = 3.68 mg/mL). Both showed high total phenolic and tannin contents. In sum, PM-EO showed satisfactory antifungal activity, since its inhibitory action on mycelial growth of C. gloeosporioides was above 70% in the dry season, while it exhibited weak activity in the rainy season.