Effects of fungicide treatment on metabolite profiles of Aquilaria malaccensis

Aquilaria malaccensis is an agarwood-producing tree. Previous studies have shown that endophytic fungi may colonize A. malaccensis. Endophytes are known to be capable of altering plants' secondary metabolites, although the mechanism adopted by the plants remains unclear. This paper aimed to observe the differences in the metabolite profiles of A. malaccensis by eliminating the presence of endophytic fungi with fungicide. Three solvents i.e., ethanol, ethyl acetate, and chloroform, were used for extracting the 2-year-old A. malaccensis. The extracts were examined by scanning with UV–Vis Spectrophotometry and Gas Chromatography-Mass Spectrometry (GC-MS) for the metabolites profile. The absorbances data were analyzed using Principal Component Analysis (PCA), followed by Partial Least Squares-Discriminant Analysis (PLS-DA). The results showed that groupings between control and fungicide-treated extract formed in the PLS-DA score plot. The important wavelength values for the separation were identified. Identification of compounds found inside the A. malaccensis plants based on the GC-MS results was conducted. Several compounds were specifically found in the control-treated extract of A. malaccensis plants. Respectively, the total phenolics and total flavonoids inside the A. malaccensis extract were calculated using Folin-Ciocalteu's and aluminum chloride tests. A decrease in phenolic and flavonoid content was observed mostly in the roots. These findings are fundamental to understanding endophytes' ability to alter the secondary metabolites produced in A. malaccensis.