Profiling Flavonoids in Plant Samples

Plant samples were extracted with methanol (final concentration 75% v/v, containing 25 µM of 7-hydroxy-5-methylflavone as an internal standard). After homogenizing the samples, centrifugation, and filtration, hydrophobic compounds in the filtrate were removed by absorption to a C18 silica column (MonoSpin C18, GL Science, Tokyo, Japan). Standard compounds for FsDatabase construction and identification of parsley peaks were dissolved in methanol. LC-MS analyses were performed using Agilent 1100 or 1200 systems (Agilent, Palo Alto, CA) coupled to a Finnigan LTQ-FT (Thermo Fisher Scientific) or a Finnigan LTQ-Orbitrap XL (Thermo Fisher Scientific). The binary raw data from Xcalibur (.raw) and their experimental metadata for plant samples are deposited at MassBase^{27 (link)} and Metabolonote³¹ , respectively. Their IDs and peak data are available at the KOMICS website^{27 (link)} (http://www.kazusa.or.jp/komics/software/FlavonoidSearch). The details of the extraction and analysis procedures were described in Supplementary Methods.