Table 2 Tentative identification of potential anti-cholinesterase alkaloids selected from S-plot applying a cut-off for correlation (p[corr]) and covariance (w *).

VarID	Rt (min)	[M+H] +/M+ (m/z)	Molecular formula	Error (ppm)	MS2 (m/z)	Tentative identification
9POS	18.327	354.1697	C H NO + 21 24 4	−0.80	190.0863 (100)
						N-methylcanadine
48POS	30.968	350.13840	C21H19NO4	−0.81	334.1070 (100)
					318.1105 (21.4) 304.1040 (22.8) 290.0790 (10.7)		dihydrohelerythrine
232POS	18.666	348.12299	C H NO + 21 18 4	−0.13	332.0917 (100) 318.0755 (50.5) 304.0966 (57.7) 290.0808 (28.0)
						Chelerythrine
419POS	18.439	336.12290	C H NO + 20 18 4	−0.40	321.0940 (39.7) 320.0920 (100) 306.0724 (38.3) 292.0965 (72.0) 278.0777 (16.1)
40POS 293POS	17.815 30.593	354.17007 406.16498	C H NO + 21 24 4 C24H23NO5	0.23 0.20	190.0901 (100) 348.1201 (100) 332.0910 (76.0) 318.1105 (32.3) 304.1040 (35.0) 290.0790 (7.78)	Berberine N-methylcanadine (Isomer)
						6-acetonyldihydrochelerythrine
123POS	17.912	338.13870	C H NO + 20 20 4	0.04	338.1382 (6.65) 323.1140 (50.0) 322.1090 (100)
					308.0910 (51.9) 294.1101 (61.6) 280.0990 (20.8)	columbamine
284POS	28.499	408.14441	C23H21NO6	0.60	348.1221 (100) 332.0910 (37.9) 318.1105 (12.1) 304.1040 (15.9)
						6-acetyldihydrochelerythrine
301POS	27.079	364.11798	C H NO + 21 18 5	0.09	349.0940 (43.7) 334.0720 (100) 320.0910 (25.8) 306.0691 (19.5) 301.0710 (7.6)
						6-oxychelerythrine
432POS	27.856	392.14932	C H NO + 23 22 5	0.18	348.1220 (100) 332.0910 (37.9) 318.1105 (12.1) 304.1040 (15.9)
						6-methoxychelerythrine
825POS	18.199	334.10757	C H NO + 20 16 4	0.56	319.0830 (100) 304.0600 (21.8)
					291.0901 (26.1)		fagaridine