Bioassay-guided fractionation of the organic extracts of whole plants of Mostuea brunonis (Loganiaceae), using the National Cancer Institute's (NCI) human tumor-based in vitro antitumor screen, led to the isolation and identification of camptothecin 20-O-β-D-glucoside (1) and three moderately cytotoxic alkaloids, the known deoxypumiloside (2) and strictosamide (3), and the new 2'-O-acetylstrictosamide (4), from the cytotoxic alkaloid fractions. While the previously unknown 20-O-β-D-glucopyranosyl camptothecin exhibited greater solubility in alcohol, DMSO-H2O and H2O than camptothecin, it was essentially inactive in the NCI's in vitro 60-cell line primary antitumor screen. However, it could be vulnerable to de-glucosidation in vivo, and may, therefore, merit additional evaluation as a potential prodrug of camptothecin that could be more readily formulated than the parent agent.

antitumor activity, Mostuea brunonis, cytotoxic alkaloid, camptothecin glycoside

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15	C16	C17	C18	C19	C20
20	bDGlcp	101.1	75.6	78.1	71.1	78.2	62.2
	Subst	153.9	146.2	51.4	130.9	133.3	129.9	129.7	129.1	131.9	129.8	149.6	101.5	149.2	122.0	168.3	67.8	8.4	33.9	79.1	171.1


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11	H12	H13	H14	H15	H16	H17	H18	H19	H20
20	bDGlcp	4.67	3.38	3.04	3.24	3.33	3.41-3.61
	Subst	-	-	5.36	-	8.65	-	8.08	7.72	7.88	8.21	-	7.84	-	-	-	5.43-5.62	0.96	2.17-2.32	-	-


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11	C12/H12	C13/H13	C14/H14	C15/H15	C16/H16	C17/H17	C18/H18	C19/H19	C20/H20
20	bDGlcp	101.1/4.67	75.6/3.38	78.1/3.04	71.1/3.24	78.2/3.33	62.2/3.41-3.61
	Subst			51.4/5.36		133.3/8.65		129.7/8.08	129.1/7.72	131.9/7.88	129.8/8.21		101.5/7.84				67.8/5.43-5.62	8.4/0.96	33.9/2.17-2.32		

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CC[C@@]1(O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)C(=O)OCc2c1cc1n(c2=O)Cc2cc3ccccc3nc2-1

510.499 g/mol (C₂₆H₂₆N₂O₉)

Bioassay-guided fractionation of the organic extracts of whole plants of Mostuea brunonis (Loganiaceae), using the National Cancer Institute's (NCI) human tumor-based in vitro antitumor screen, led to the isolation and identification of camptothecin 20-O-β-D-glucoside (1) and three moderately cytotoxic alkaloids, the known deoxypumiloside (2) and strictosamide (3), and the new 2'-O-acetylstrictosamide (4), from the cytotoxic alkaloid fractions. While the previously unknown 20-O-β-D-glucopyranosyl camptothecin exhibited greater solubility in alcohol, DMSO-H2O and H2O than camptothecin, it was essentially inactive in the NCI's in vitro 60-cell line primary antitumor screen. However, it could be vulnerable to de-glucosidation in vivo, and may, therefore, merit additional evaluation as a potential prodrug of camptothecin that could be more readily formulated than the parent agent.

antitumor activity, Mostuea brunonis, cytotoxic alkaloid, camptothecin glycoside

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15	C16	C17	C18	C19	C20
21,2	Ac	171.0	19.7
21	bDGlcp	96.2	74.1	75.3	71.5	78.4	62.4
	Subst	134.6	55.2	45.0	22.0	110.1	128.6	118.4	119.9	122.3	112.4	137.9	26.9	25.1	109.9	166.9	148.4	120.6	133.7	44.0	96.1


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11	H12	H13	H14	H15	H16	H17	H18	H19	H20
21,2	Ac	-	1.20
21	bDGlcp	4.68	4.44	3.41	3.24	3.33	3.63-3.86
	Subst	-	5.07	3.15-4.93	2.70-2.95	-	-	7.37	6.98	7.07	7.33	-	2.01-2.45	2.62	-	-	7.35	5.37	5.32-5.63	2.59	5.40


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11	C12/H12	C13/H13	C14/H14	C15/H15	C16/H16	C17/H17	C18/H18	C19/H19	C20/H20
21,2	Ac		19.7/1.20
21	bDGlcp	96.2/4.68	74.1/4.44	75.3/3.41	71.5/3.24	78.4/3.33	62.4/3.63-3.86
	Subst		55.2/5.07	45.0/3.15-4.93	22.0/2.70-2.95			118.4/7.37	119.9/6.98	122.3/7.07	112.4/7.33		26.9/2.01-2.45	25.1/2.62			148.4/7.35	120.6/5.37	133.7/5.32-5.63	44.0/2.59	96.1/5.40

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C=C[C@H]1[C@H](O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2OC(C)=O)OC=C2C(=O)N3CCc4c([nH]c5ccccc45)[C@@H]3C[C@H]21

540.569 g/mol (C₂₈H₃₂N₂O₉)

Bioassay-guided fractionation of the organic extracts of whole plants of Mostuea brunonis (Loganiaceae), using the National Cancer Institute's (NCI) human tumor-based in vitro antitumor screen, led to the isolation and identification of camptothecin 20-O-β-D-glucoside (1) and three moderately cytotoxic alkaloids, the known deoxypumiloside (2) and strictosamide (3), and the new 2'-O-acetylstrictosamide (4), from the cytotoxic alkaloid fractions. While the previously unknown 20-O-β-D-glucopyranosyl camptothecin exhibited greater solubility in alcohol, DMSO-H2O and H2O than camptothecin, it was essentially inactive in the NCI's in vitro 60-cell line primary antitumor screen. However, it could be vulnerable to de-glucosidation in vivo, and may, therefore, merit additional evaluation as a potential prodrug of camptothecin that could be more readily formulated than the parent agent.

antitumor activity, Mostuea brunonis, cytotoxic alkaloid, camptothecin glycoside

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C=C[C@H]1[C@H](O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)OC=C2C(=O)N3CCc4c([nH]c5ccccc45)[C@@H]3C[C@H]21

498.532 g/mol (C₂₆H₃₀N₂O₈)

Bioassay-guided fractionation of the organic extracts of whole plants of Mostuea brunonis (Loganiaceae), using the National Cancer Institute's (NCI) human tumor-based in vitro antitumor screen, led to the isolation and identification of camptothecin 20-O-β-D-glucoside (1) and three moderately cytotoxic alkaloids, the known deoxypumiloside (2) and strictosamide (3), and the new 2'-O-acetylstrictosamide (4), from the cytotoxic alkaloid fractions. While the previously unknown 20-O-β-D-glucopyranosyl camptothecin exhibited greater solubility in alcohol, DMSO-H2O and H2O than camptothecin, it was essentially inactive in the NCI's in vitro 60-cell line primary antitumor screen. However, it could be vulnerable to de-glucosidation in vivo, and may, therefore, merit additional evaluation as a potential prodrug of camptothecin that could be more readily formulated than the parent agent.

antitumor activity, Mostuea brunonis, cytotoxic alkaloid, camptothecin glycoside

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

C=C[C@H]1[C@H](O[C@@H]2O[C@H](CO)[C@@H](O)[C@H](O)[C@H]2O)OC=C2C(=O)N3Cc4c([nH]c5ccccc5c4=O)[C@@H]3C[C@H]21

512.515 g/mol (C₂₆H₂₈N₂O₉)