Metabolomic Profiling of Tecoma Plant Extracts

Leaves of Tecoma species and cultivars under study (1600 g) were exhaustively extracted with methanol by cold maceration in 10 L methanol (2 L each × 5 times). The total methanolic extract was evaporated under reduced pressure by rotary evaporator at a temperature not exceeding 45 °C, yielding 180–200 mg of total methanolic extract of each studied plants. About 2 mg of each crude methanolic extract was dissolved separately in 1 ml MeOH and filtered using 0.2 μm membrane filter and then subjected to LC-HRESIMS analysis as previously reported in ref. 24 (link). An Acquity Ultra-Performance Liquid Chromatography (UPLC) system coupled to a Synapt G2 HDMS quadrupole time-of-flight hybrid mass spectrometer (Waters, Milford, MA, USA). Chromatographic separation was performed using a BEH C18 column (2.1 × 100 mm, 1.7 mm particle size) and a guard column (2.1 × 5 mm, 1.7 mm particle size) using the method previously described in ref. 19 (link). Fig. S1† depicts the total ion chromatograms of the eight studied plants. MZmine 2.12 was used for processing the obtained raw data by the negative ionization mode. The processed data set was then subjected to molecular formula prediction and peak identification via dereplication using online METLIN^{25 (link)} and Dictionary of Natural Products (DNP)^{26 (link)} databases.