Table 1.
Identification of secondary metabolites of the methanol extract from the bark of Senna singueana by HPLC-MS/MS.
| No. | Rt (min) | [M − H]− | MS/MS | Proposed Compounds | Ref. |
|---|---|---|---|---|---|
| 1 | 1.33 | 133 | 115 | Malic acid | [26] |
| 2 | 1.68 | 447 | 163, 315 | p-Coumaric acid galloyl-pentoside | |
| 3 | 2.48 | 153 | Protocatechuic acid | ||
| 4 | 4.52 | 305 | 179, 221, 287 | (epi)Gallocatechin | [25] |
| 5 | 5.33 | 417 | 161, 205, 270 | Unknown | |
| 6 | 5.90 | 593 | 289, 441 | (epi)Catechin digallate | |
| 7 | 8.18 | 305 | 125, 179, 287 | (epi)Gallocatechin | [25] |
| 8 | 8.48 | 593 | 305, 425, 575 | (epi)Gallocatechin-(epi)catechin | [25] |
| 9 | 9.57 | 289 | 179, 205, 245 | (epi)Catechin | [26] |
| 10 | 11.52 | 577 | 289, 425, 559 | (epi)Catechin-(epi)catechin | [26] |
| 11 | 13.10 | 577 | 289, 425, 559 | (epi)Catechin-(epi)catechin | [26] |
| 12 | 14.65 | 289 | 179, 205, 245 | Catechin | [26] |
| 13 | 15.76 | 561 | 179, 305, 543 | (epi)Guibourtinidol-(epi)gallocatechin | |
| 14 | 17.14 | 561 | 289, 451, 543 | (epi)Catechin-(epi)afzelechin | [26] |
| 15 | 17.90 | 561 | 179, 305, 543 | (epi)Guibourtinidol-(epi)gallocatechin | |
| 16 | 20.16 | 561 | 179, 305, 543 | (epi)Guibourtinidol-(epi)gallocatechin | |
| 17 | 20.87 | 545 | 289, 409, 527 | (epi)Guibourtinidol-(epi)catechin | [27] |
| 18 | 21.82 | 561 | 179, 305, 543 | (epi)Guibourtinidol-(epi)gallocatechin | |
| 19 | 24.20 | 545 | 179, 289, 527 | (epi)Guibourtinidol-(epi)catechin | [27] |
| 20 | 26.37 | 545 | 179, 289, 527 | (epi)Guibourtinidol-(epi)catechin | [27] |
| 21 | 27.82 | 545 | 179, 289, 527 | (epi)Guibourtinidol-(epi)catechin | [27] |
| 22 | 28.64 | 545 | 179, 305, 527 | (ent)Cassiaflavan-(epi)gallocatechin | [28] |
| 23 | 29.30 | 545 | 179, 305, 527 | (ent)Cassiaflavan-(epi)gallocatechin | [28] |
| 24 | 31.31 | 833 | 305, 561, 577 | (epi)Gallocatechin-(epi)catechin-(ent)cassiaflavan | |
| 25 | 33.96 | 529 | 289, 419, 511 | (ent)Cassiaflavan-(epi)catechin | [28] |
| 26 | 34.72 | 817 | 305, 561, 663 | (epi)Guibourtinidol-(epi)guibourtinidol-(epi)gallocatechin | |
| 27 | 37.58 | 833 | 305, 593, 723 | (epi)Gallocatechin-(epi)catechin-(ent)cassiaflavan | |
| 28 | 37.73 | 529 | 179, 289, 511 | (ent)Cassiaflavan-(epi)catechin | [28] |
| 29 | 40.56 | 801 | 289, 545, 691 | (epi)Guibourtinidol-(epi)guibourtinidol-(epi)catechin | |
| 30 | 45.35 | 801 | 305, 561, 691 | (ent)Cassiaflavan-(epi)guibourtinidol-(epi)gallocatechin | |
| 31 | 46.41 | 785 | 305, 545, 767 | (ent)Cassiaflavan-(ent)cassiaflavan-(epi)gallocatechin | |
| 32 | 48.75 | 801 | 305, 425, 561 | (ent)Cassiaflavan-(epi)guibourtinidol-(epi)gallocatechin | |
| 33 | 53.87 | 785 | 289, 545, 675 | (ent)Cassiaflavan-(epi)guibourtinidol-(epi)catechin | |
| 34 | 55.50 | 785 | 305, 545, 675 | (ent)Cassiaflavan-(ent)cassiaflavan-(epi)gallocatechin | |
| 35 | 56.50 | 785 | 305, 545, 675 | (ent)Cassiaflavan-(ent)cassiaflavan-(epi)gallocatechin | |
| 36 | 58.62 | 769 | 289, 529 | (ent)Cassiaflavan-(ent)cassiaflavan-(epi)catechin |
Prefixes (epi) and (ent) indicate that the stereochemistry of the compounds is not resolved.