## 3 Results and Discussion
### Identification of Flavonoids in Fig Leaves
According to the fragment ions in the secondary mass spectrum and the related literature, we speculated that the compound was 2-carboxyl-1.4-naphthohydroquinone-4-O-hexoside [38]. Compound **7** (\(\mathrm{t_{R}}=13.89\) min) was the main flavonoid in fig leaves. This showed the MS spectrum [M - H]\({}^{-}\) ion at \(m/z\) 609.1407, and the product ions at \(m/z\) 301.0362, 151.0031, 257.0450, and 273.0477 were generated. Under the bombardment of 25% energy, the quercetin 3-O-hexobioside aglycone was lost to form fragments of \(m/z\) 301.0362. In the tandem mass spectrometry of the \(m/z\) 301.0362 ion, there were three main ways of fragmentation. The first was fragmentation of \(m/z\) 301.0362 through RDA to form fragments of \(m/z\) 151. The second type was fragmentation of \(m/z\) 301. The loss of the carbonyl group from the C ring formed fragments of \(m/z\) 273.0477. The compound was identified as quercetin 3-O-hexobioside [41]. Compound **11** was eluted at 15.25 min. It showed the [M - H]\({}^{-}\) ion at \(m/z\) 593.1524 and the product ions at \(m/z\) 285 [M-162-146-H]\({}^{-}\) were generated. The quasi-molecular ion peak lost a neutral fragment of \(m/z\) 309, resulting in fragment ions [M-H-308]\({}^{-}\) (\(m/z\) 285). According to the relative molecular mass, the neutral fragment of \(m/z\) 308 was initially judged to be rutin. According to the literature, the substance was kaempfer 3-O-hexobioside [42]. Compounds **3**, **4**, **5**, **6**, **8**, and **9** are all flavonoid glycosides [38]. Quasi-molecular ion peaks appeared in negative ion modes for the flavonoid carboglycos. The negative ion mode showed higher abundance for fragment ions. We observed the ring-opening and cleavage of the sugar ring and the subsequent neutral loss of sugar residues, CO, aglycion loss, CH\({}_{3}\), and other fragment ion peaks. The ring-opening cleavage of the sugar ring is the characteristic cleavage form of carbon glycosides. This mainly occurs in the sugar ring 0, 2 bond and 0, 3 bond, hexose neutral loss of C\({}_{4}\)H\({}_{8}\)O\({}_{4}\) or C\({}_{3}\)H\({}_{6}\)O\({}_{3}\), and the neutral loss of pentose C\({}_{3}\)H\({}_{6}\)O\({}_{3}\) or C\({}_{2}\)H\({}_{4}\)O\({}_{2}\). Compound **3** (\(\mathrm{t_{R}}=11.7\) min) had the [M - H]\({}^{-}\) ion at \(m/z\) 579.1366, and the product ions at \(m/z\) 519.1194, 489.1083, 429.0856, 399.0748, 369.0635, and 339.0521 were generated. At \(m/z\) 519.1194, a fragment ion was obtained after the precursor ion lost a C\({}_{2}\)H\({}_{4}\)O\({}_{2}\) fragment [M-H-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)]\({}^{-}\). The \(m/z\) 489.1083 represents the fragment ion obtained after the precursor ion had lost 90 Da [M-C\({}_{3}\)H\({}_{6}\)O\({}_{3}\)-H]\({}^{-}\). The \(m/z\) 429.0856 represents the fragment ion obtained after the precursor ion had lost 150 Da [M-C\({}_{3}\)H\({}_{6}\)O\({}_{3}\)-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)-H]\({}^{-}\). The \(m/z\) 399.0748 represents the fragment ion obtained by discarding 180 Da of the precursor ion [M-C\({}_{2}\)H\({}_{4}\)O\({}_{2}\)-C\({}_{4}\)H\({}_{8}\)O\({}_{4}\)-H]\({}^{-}\). The \(m/z\) 369.0635 represents the fragment ion obtained by losing 120 Da of the precursor ion [M-C\({}_{7}\)H\({}_{14}\)O\({}_{7}\)-H]\({}^{-}\). The \(m/z\) 339.0521 represents the fragment ion obtained by discarding 240 Da of the precursor ion [M-C\({}_{7}\)H\({}_{14}\)O\({}_{7}\)-CH\({}_{2}\)O-H]\({}^{-}\). According to the fragment ions in the secondary mass spectrum and related literature, we speculated that the compound was luteolin 6-C-hexoside, 8-C-pentoside [43]. The retention time of Compound **4** was 12.58 min. Compound **4** had the [M - H]\({}^{-}\) ion at \(m/z\) 563.1414, and the product ions at \(m/z\) 473.1115,443.1001, and 353.0670 were generated. It was identified as kaempfer 6-C-hexoside-8-C-hexoside [44]. The \(m/z\) 563 [M - H]\({}^{-}\) is its quasi-molecular ion peak, and \(m/z\) 443.1001, 473.1115, and 353.0670 are the main fragments produced by its cracking. The most abundant fragment ion in MS\({}_{2}\) was \(m/z\) 443.