## 3 Experimental Section
### LC-ESI-MS analysis  
RP-LC-ESI-MS analysis of human urine samples was performed with the use of an ACQUITY UPLC system composed of a binary solvent manager, a sample manager, a column manager, and a TUV detector (Water Corp., Milford, MA). Although this configuration of UPLC hardware could reach as high as 15,000 psi, a working back pressure of 10,000 psi was targeted. A BEH C\({}_{18}\) shielded column (1.7 \(\mu\)m, 150 x 2 mm) was used. Mobile phases used: A, ammonium acetate, 13 mM, pH 5.5; B, acetonitrile. After a 0.1 min isocratic run at 0% B, a gradient to 40% B was concluded at 8 min, and then it ramped at 95% B up to 9 min and maintained until 10.5 min. Following column wash was equilibration with 0% B at 11 min and maintained until 15 min. All injection volumes were 5 \(\mu\)L and column temperature was 35 \({}^{\circ}\)C, while the flow rate was 0.4 mL/min. Weak wash solvent was H\({}_{2}\)O-methanol (1:1, v/v) and strong wash solvent was acetonitrile-isopropanol (3:1, v/v).  
HILIC-LC-ESI-MS analysis of human urine samples was performed with the use of a polyamine-bonded polymeric gel column (apHera NH\({}_{2}\), 100 x 2 mm, 3 \(\upmu\)m particle size, Advanced Separations Technologies, Whippany, NJ; apHera amino columns are based on covalently bonded strong alkaline compatible polyamine with a working pH range of 2 -13). The mobile phases were: acetonitrile (A), 13 mM ammonium acetate (pH 5.5, adjusted by acetic acid) (B), and 100 mM ammonium bicarbonate (pH 9.4, adjusted with ammonium hydroxide) (C) at the flow rates of 0.5 mL/min at 25\({}^{\circ}\)C. After a 1-min isocratic run at 5% B, a gradient to 35% B was concluded at 11 min, and then B was replaced by C starting at 50%, and gradient to 75% C was completed at 20 min. Following column wash the run was concluded with 100% C at 22 min. Column equilibration with starting buffer took 15 min before the next injection. The purpose of using mobile phase C at later stage of the gradient was to elute very polar compounds on the column. Since mobile phase C had a high pH value, a strong alkaline compatible HILIC column was used for this application. The injection volume was set to 5 \(\upmu\)L. Weak wash solvent was acetonitrile-isopropanol (3:1, v/v) and strong wash solvent was H\({}_{2}\)O-methanol (1:1, v/v). For HILIC-LC-ESI-MS analysis, oligosaccharides were used as retention time indexes because they elute in the order of the increasing monomer units, with larger oligomers eluting as the latest ones. Mono and oligosaccharides are detected as ammonia adducts in positive mode and as [M-H] ions in negative mode. The entire effluent from the HPLC column was directed into the electrospray ionization source (ESI) of a LTQ linear ion trap MS (ThermoFinnigan, San Jose, CA) operated under Xcalibur software (V1.4, ThermoFinnigan, San Jose, CA). The electrospray voltage was set to 5 kV. Nitrogen sheath and auxiliary gas flow was 60 and 20 arbitrary units respectively. The ion transfer capillary temperature was 350 \({}^{\circ}\)C. Typical ion gauge pressure was \(0.90\times 10^{-5}\). Full scan spectra were acquired from 150-850 amu at unit mass resolution with maximum injection time set to 200 ms in one micro scan. Acquisition was performed in both positive and negative switching modes. Sucrose tune file was used during all the LC-ESI-MS acquisitions on LTQ mass spectrometer. LC-MS protocols for the analysis of pine needles were described earlier [34].