## 3 Results
### Phytochemical Profiling of Syzygium formosum Leaves Using LC-MS/MS
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Groups** & **Compounds** & **Molecular Formula** & **Retention Time (min)** & **Precursor Ion (_m/z_)** & **Product Ions (_m/z_)** \\ \hline \multirow{8}{*}{Flavonoids} & Catechin & C\({}_{15}\)H\({}_{15}\)O\({}_{6}\) & 1.52 & 291.1 [M+H]\({}^{+}\) & 139, 123 \\  & EGCG & C\({}_{22}\)H\({}_{85}\)O\({}_{11}\) & 2.46 & 459.0 [M+H]\({}^{+}\) & 139, 289 \\  & Myricetin glucoside & C\({}_{21}\)H\({}_{23}\)O\({}_{13}\) & 4.06 & 481.1 [M+H]\({}^{+}\) & 319, 145 \\  & Myricetin rhamno & C\({}_{21}\)H\({}_{23}\)O\({}_{12}\) & 5.49 & 465.1 [M+H]\({}^{+}\) & 319, 129 \\  & Quercetin glucoside & C\({}_{21}\)H\({}_{23}\)O\({}_{21}\) & 6.02 & 465.1 [M+H]\({}^{+}\) & 303, 145 \\  & Quercetin arabinoside & C\({}_{21}\)H\({}_{23}\)O\({}_{11}\) & 6.79 & 435.1 [M+H]\({}^{+}\) & 303, 133 \\  & Quercetin rhamno & C\({}_{21}\)H\({}_{23}\)O\({}_{11}\) & 6.97 & 449.0 [M+H]\({}^{+}\) & 303, 129 \\  & Quercetin & C\({}_{15}\)H\({}_{10}\)O\({}_{7}\) & 8.30 & 303.1 [M+H]\({}^{+}\) & 153, 137 \\ \hline \multirow{4}{*}{Phenolic acids} & Gallic acid & C\({}_{2}\)H\({}_{4}\)O\({}_{5}\) & 1.15 & 168.9 [M+H]\({}^{-}\) & 125, 79 \\  & 3.4-DHBA & C\({}_{2}\)H\({}_{6}\)O\({}_{4}\) & 1.77 & 153.0 [M+H]\({}^{-}\) & 109, 91 \\  & _p_-cumaric acid & C\({}_{6}\)H\({}_{6}\)O\({}_{3}\) & 5.57 & 162.9 [M\(-\)H]\({}^{-}\) & 119, 93 \\ \hline \multirow{8}{*}{Triterpenoids} & Madecassic acid & C\({}_{30}\)H\({}_{48}\)O\({}_{6}\) & 3.68 & 469.3 [M\(-\)2H\({}_{2}\)O+H]\({}^{+}\) & 189.1, 235.1 \\  & Asiatic acid & C\({}_{30}\)H\({}_{48}\)O\({}_{5}\) & 4.61 & 453.3 [M\(-\)2H\({}_{2}\)O+H]\({}^{+}\) & 187.1, 203.1 \\ \cline{1-1}  & Hederagenin & 7.08 & 455.3 [M\(-\)O\({}_{4}\)H\({}^{+}\)O+H]\({}^{+}\) & 177.1, 189.1 \\ \cline{1-1}  & Maslinc acid & C\({}_{30}\)H\({}_{48}\)O\({}_{4}\) & 8.53 & 455.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 189.1, 203.1 \\ \cline{1-1}  & Corosolic acid & 8.93 & 455.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 189.1, 205.1 \\ \cline{1-1}  & Betulin & C\({}_{30}\)H\({}_{30}\)O\({}_{2}\) & 11.71 & 425.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 191.1, 217.1 \\ \cline{1-1}  & Betulinic acid & 12.66 & 439.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 137.1, 191.1 \\ \cline{1-1}  & Oleanolic acid & C\({}_{30}\)H\({}_{48}\)O\({}_{3}\) & 13.67 & 439.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 191.1, 203.1 \\ \cline{1-1}  & Ursolic acid & 13.98 & 439.3 [M\(-\)H\({}_{2}\)O+H]\({}^{+}\) & 191.1, 203.1 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: List of phenolic compounds and triterpenoids detected in _Syzygium formosum_ leaves by UPLC-MS/MS. a linkage isomer of quercetin-glucose. Regarding the precursor ion mass of \(m/z\) 481.1, a peak with the retention time of 4.06 min was identified as myricetin-glucoside by a reference standard. Additionally, one isobaric component was also found at different retention time, and it was determined as a myricetin-hexose glycoconjugate that was predicted to be a linkage isomer of myricetin-glucose. Figure 1: _Cont_. Under extracted ion chromatogram of m/z 303.1, in addition to a peak that appeared at the retention time of 8.30 min, which was confirmed to be quercetin aglycon by a reference standard, there were some other peaks with the same mass found at different retention time. The _m/z_ 303.1 was the product ion mass formed by the fragmentation of precursor ions including glycoconjugates of quercetin based on the MS/MS spectra. By extraction of molecular ion mass of _m/z_ 459.0, we can see that some independent peaks appeared at distinct retention time. A peak with retention time at 2.46 min was confirmed to be epigallocatechin gallate (EGCG) when comparing to retention time of a reference standard. For phenolic acids, from peak 1 to peak 3 shown in Supplementary Figure S1, the deprotonated molecular ions were _m/z_ 169, _m/z_ 153, and _m/z_ 163, and their corresponding product ions were _m/z_ 125, _m/z_ 109, and _m/z_ 119.