Seasonal metabolic variation in the essential oil composition of various Tabebuia species and evaluation of their anti-inflammatory activity in vitro and in silico.

Abstract

The seasonal variation in essential oil from four Tabebuia species, T. impetiginosa, T. rosea, T. argentea, and T. guayacan, was explored using gas chromatography-mass spectrometry analysis. A total of 90 components were tentatively identified. Among the four Tabebuia species, the most predominant components in spring were phytol (67.5%), limonene (50.1%), (Z,Z,Z)-7,10,13-hexadecatrienal (67.5%), and 1-octen-3-ol (80.4%), respectively. Chemometric discrimination of the four Tabebuia species was performed employing principal component analysis, which classified the samples into three main clusters while the rest of the samples were scattered in the whole plot. The season of collection impact on essential oils composition and yield was illustrated. 5-Lipooxygenase inhibitory effect of spring season essential oils was assessed, showing that all essential oils exhibited certain inhibition, where T. rosea showed the most potent effect, exhibiting an IC50 value of 1.8 μg/mL, compared to the standard zileuton (0.68 μg/mL). Moreover, an in silico molecular docking study was performed for the predominant metabolites against the 5-LOX active pocket. Among all the docked compounds, eicosane showed the best fitting score, then norphytane, with ∆G of -38.39 and -29.77 kcal/mol, respectively. Thus, Tabebuia species could offer a natural and relatively safe anti-inflammatory candidate that requires further clinical trials to be supported.