Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry for Identification of In Vitro and In Vivo Metabolites of Bornyl Gallate in Rats

Table 1

Retention time (RT), measured mass, calculated formula by elemental compositions, the mass error between the calculated and measured values, MS/MS fragment ions, and metabolic pathway as well as relative peak ratio for each metabolite of BG in rat plasma and urine after oral administration.

Compound	RT; (min)	Measured mass (𝑚/𝑧)	Mass error (ppm)	Relative peak ratio^a in urine	Relative peak ratio in plasma	Formula	MS/MS fragment ions	Metabolic pathway
M0	63.0	305.1400	−1.8	100	100	C17H22O5	169, 168, 125, 124	Parent drug
M1a	49.0	321.1350	−2.0	0.68	∖ ^b	C17H22O6	169, 168, 125, 124	Hydroxylation
M1b	51.8	321.1348	−1.4	0.53	∖
M1c	53.9	321.1349	−1.7	0.41	∖
M2	13.9	169.0145	−1.5	0.69	∖	C7H6O5	125, 124, 79, 51	Hydrolysis
M3	24.4	345.0469	−1.6	3.66	1.38	C13H14O11	169, 125, 124	Hydrolysis + glucuronidation
M4a	31.8	183.0302	−1.7	0.38	∖	C8H8O5	168, 124, 123, 95, 78	Hydrolysis + O-methylation
M4b	32.1	183.0304	−2.8	0.32	∖
M5a	50.5	497.1674	−1.9	0.99	2.86	C23H30O12	321, 175, 113	Hydroxylation + glucuronidation
M5b	52.9	497.1681	−3.3	0.90	∖
M5c	56.3	497.1678	−2.7	2.44	2.36
M6	56.4	657.2043	−1.0	1.08	13.6	C29H38O17	481, 305, 175, 113	Di-glucuronidation
M7a	60.1	481.1722	−1.4	24.64	105.24	C23H30O11	305, 124, 113	glucuronidation
M7b	67.5	481.1728	−2.6	50.96	916.65
M8a	60.9	495.1883	−2.3	95.36	31.7	C24H32O11	319, 304, 175, 113	O-methylation + glucuronidation
M8b	62.6	495.1879	−1.4	3.66	16.95
M8c	66.7	495.1877	−1.1	2.68	2.01
M9a	65.5	319.1556	−1.6	0.39	3.09	C18H24O5	304, 168, 124	O-methylation
M9b	66.0	319.1560	−2.8	1.31	0.86

^aRelative peak ratio was calculated on the basis of EIC as follows: (relative peak ratio) = (the peak area of metabolite)/(the peak area of parent, M0) × 100.
^b∖: undetected.