Chemometrics of the Seasonal Influence on Chemical Composition, Yield, Antioxidant Capacity, and Anti‐Candida Activity of <i>Alpinia nutans</i> Essential Oil Growing in the Brazilian Amazon Region

Alpinia nutans (L.) Roscoe (Zingiberaceae) is used in folk medicine as an antiviral, anti-inflammatory, and antioxidant. This study aimed to evaluate the seasonality effects on the yield, chemical composition, antioxidant capacity, and anti-Candida activity of the A. nutans essential oil (EO). The specimen was collected monthly for 1 year in Belém, Pará, Brazil. The leaf EOs were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC/MS), and the antioxidant capacity was evaluated by DPPH and β-carotene/linoleic acid. The EO yield showed no significant difference between dry (1.80% ± 0.29) and rainy (1.75% ± 0.11) seasons. The main chemical constituents identified in the EOs were terpinen-4-ol (13.93%-23.14%), 1,8-cineole (15.83%-18.43%), and p-cymene (14.41%-20.16%). Hierarchical cluster analysis (HCA) and principal component analysis (PCA) showed three groups with major constituents in different proportions. None of the samples showed significant inhibition in the DPPH and β-carotene/linoleic acid antioxidant method. Analyzing the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), the samples from dry and rainy seasons showed high activity against strains of Candida albicans (MIC 5 mg/mL; MFC 10 mg/mL), Candida parapsilosis (MIC 2.5 mg/mL; MFC 10 mg/mL), and Candida tropicalis (MIC 10 mg/mL; MFC 10 mg/mL). There were only quantitative variations in the chemical composition of A. nutans EO. The anti-Candida potential of the EO was also not influenced by seasonality. The A. nutans EO may be promising to produce anti-Candida phytopharmaceuticals. However, the chemical variability of this species throughout the year should be considered for this purpose.