Volatile oils from Psidium guineense Swartz leaves: Chemical seasonality, antimicrobial, and larvicidal activities

Psidium guineense Swartz is a shrub used in urinary tract diseases, diarrhea, and dysentery. The aims of this study were to analyze the seasonal chemical variability of the volatile oils of P. guineense leaves for 12 months, to evaluate the antimicrobial activity against bacteria and fungus, and the larvicidal activity against third-instarAedes aegypti larvae. The identification of the volatile oil components was performed by gas chromatography coupled with mass spectrometry (GC -MS). The antimicrobial and larvicidal activities were assessed by in vitro methodologies. The majority compounds of the volatile oil were (2Z,6E)-farnesol (15.1-51.2%), -copaene (5.9-24.6%) and muurola-4,10(14)-dien-1 beta-ol (2.7-9.6%). The composition varied according to rainfall occurrence: Cluster I (volatile oils from leaves collected in April, June, July, August, September, October, and December-low precipitation months), Cluster II (volatile oils from leaves collected in January, February, March, May, and November -higher precipitation levels). Cluster I and Cluster II showed strong to moderate activity against Cryptococcus neoformans (MIC = 32-64 mu g/mL) and Micrococcus luteus (MIC = 16-32 mu g/mL) while promising larvicidal activity was observed against Ae. aegypti (LC50 20.5-36.4 mu g/mL; LC90 47.5-70.1 mu g/mL). This is the first report describing the seasonal variability of P. guineense volatile oils, antifungal activity against yeasts, and larvicidal activity over Ae. aegypti. (C) 2022 SAAB. Published by Elsevier B.V. All rights reserved.