. 2014 Oct 2;9(10):e109479. doi: 10.1371/journal.pone.0109479

Table 4. Metabolites in MW and DM extracts from the mouse liver that were significantly different between the normal and UVB groups after 6 weeks and were tentatively identified using UPLC-Q-TOF-MS analysis.

t_R (min)^a	Tentative metabolites^b	Measured MS (m/z)		M.W.^c	HMDB Formula	Error (mDa)	Fold change^d	VIP^e	P-value
		Negative	Positive
*Glycerophospholipid metabolism*
8.09	LysoPC 22∶6^*	612.3304	568.3361	567	C₃₀H₅₀NO₇P	0.3	0.49	1.74	<0.001
8.12	LysoPE 20∶4	500.2770	502.2991	501	C₂₅H₄₄NO₇P	−0.7	0.81^DM	0.83^DM	0.019
8.15	LysoPC 20∶4^*	588.3293	544.3316	543	C₂₈H₅₀NO₇P	−0.8	0.52^MW/0.81^DM	1.67^MW/0.85^DM	<0.001^MW/0.016^DM
8.21	LysoPC 22∶6^*	612.3292	568.3396	567	C₃₀H₅₀NO₇P	−0.9	0.6	1.2	0.012
8.28	LysoPC 20∶4^*	588.3292	544.3357	543	C₂₈H₅₀NO₇P	−0.9	0.65	1.12	0.013
8.49	LysoPC 20∶3^*	590.3464	546.3596	545	C₂₈H₅₂NO₇P	0.6	0.33^MW/0.69^DM	2.22^MW/1.20^DM	<0.001^MW/0.003^DM
8.54	LysoPC 16∶0^*	540.3307	496.3435	495	C₂₄H₅₀NO₇P	0.6	0.68^MW/0.79^DM	0.93^MW/0.97^DM	0.043^MW/0.002^DM
8.65	LysoPC 20∶3^*	590.3467	546.3624	545	C₂₈H₅₂NO₇P	0.9	0.46	1.52	0.006
8.74	LysoPE 16∶0	452.2762	454.2962	453	C₂₁H₄₄NO₇P	−1.5	0.67^DM	1.29^DM	<0.001
8.79	LysoPC 16∶0^*	540.3285	496.3407	495	C₂₄H₅₀NO₇P	−1.6	0.77^DM	1.04^DM	0.002
8.80	LysoPC 18∶1^*	566.3464	522.3554	521	C₂₆H₅₂NO₇P	0.6	0.42	1.84	0.001
8.98	LysoPC 18∶1^*	566.3470	522.3516	521	C₂₆H₅₂NO₇P	1.2	0.61	1.17	0.014
8.99	LysoPE 18∶1	478.2933	480.3109	479	C₂₃H₄₆NO₇P	−0.1	0.61^DM	1.48^DM	<0.001
*Bile acid metabolsim*
4.78	Taurine conjugated cholic acid^#	514.2838	538.2732	515	C₂₆H₄₅NO₇S	−1.6	1.39^DM	0.94^DM	0.047^or
5.29	Taurine conjugated cholic acid^#	514.2843	538.2755	515	C₂₆H₄₅NO₇S	0.4	1.25	0.86	0.008
6.00	Taurine conjugated deoxycholic acid^§	498.2893	522.2805	499	C₂₆H₄₅NO₆S	0.7	1.63^MW/1.63^DM	1.37^MW/1.30^DM	<0.001^MW/0.012^DM

Variables were selected by VIP value (>0.7) and p-value (<0.05) from OPLS-DA model.

MW; MeOH/water extracts, DM; dichloromethane/MeOH extracts.

FA; formic acid, LysoPC; lysophosphatidylcholine, LysoPE; lysophosphatidylethanolamine.

t_R was retention time.

Assignment of metabolites contributing to the observed variance was performed by elemental composition analysis software with calculated mass, mass tolerance (mDa and ppm), double bond equivalent (DBE), and the iFit algorithm was implemented in the MassLynx, and by either commercial standard compounds compared with the retention time and mass spectra or HMDB (The Human Metabolome Data Base (http://www.hmdb.ca/)).

M.W.; molecular weight.

Fold change was calculated by dividing the mean of the peak intensity of each metabolite from UVB group relative to normal group.

VIP, variable important in the projection.

^*Asterisk means the two forms of lysoPC, with the fatty acyl groups at positions 1 (sn-1) or 2 (sn-2) on the glycerol backbone.

Cholic acid derivatives with taurine were not successfully identified, but it was predicted to be one of the following compounds: taurocholic acid, taurallocholic acid, tauro-b-muricholic acid, taurohyocholate, or tauroursocholic acid.

^§

Deoxycholic acid derivatives with taurine were not successfully identified, but it was predicted to be one of compounds such as tauroursodeoxycholic acid, taurodeoxycholic acid ortaurochenodesoxycholic acid.