Antiplasmodial Alkaloids from the Stem Bark ofStrychnos malacoclados

Abstract

From the stem bark of Strychnos malacoclados, one new bisindole alkaloid, 3-hydroxylongicaudatine Y (1), was isolated along with the known alkaloids vomicine (2), bisnordihydrotoxiferine (3), divarine (4), longicaudatine (5), longicaudatine Y (6), and longicaudatine F (7). All the compounds were tested for their antimalarial activity against the chloroquine-sensitive 3D7 and -resistant W2 strains of Plasmodium falciparum. Longicaudatine was the most active compound with IC₅₀ values of 0.682 and 0.573 µM, respectively. The activity of compounds 1, 3, 4, 6, and 7 against the two strains ranged from 1.191 to 6.220 µM and 0.573 to 21.848 µM, respectively. Vomicine (2), the only monomer isolated, was inactive. The alkaloids of the longicaudatine-type ( 1, 5-7) were more active than those of the caracurine-type (3- 4). The presence of the ether bridge in the molecule seems to increase the antiplasmodial activity. Compounds 1, 5, and 7 were tested against the WI-38 human fibroblast cell line. Longicaudatine was the most cytotoxic compound with an IC₅₀ of 2.721 µM. Longicaudatine F was 40-46 times more active against the two strains of P. falciparum than against the human fibroblasts and was thus considered as the more selective alkaloid. The structures of the compounds were determined based on the analysis of their spectral data.

Antiplasmodial natural products: an update

“…A cytotoxicity assay on WI-38 human fibroblasts with the most active 90 showed that the antiplasmodial activity is not specific. However, the structurally similar longicaudatine F ( 91 ), possessing an open ring in place of the six-membered oxygen heterocycle in 90 , was 40 times more selective against the parasite, despite the slightly lower antiplasmodial activity [76]. A phytochemical investigation of Strychnos icaja root provided a new bisindole, strychnobaillonine ( 93 ), and the known strychnohexamine ( 94 ) (Fig.…”

In Vitro Antioxidant and Anti-Inflammatory Activities of Alchornea Cordifolia (Schumach and Thonn.) Mull. Arg. And Antrocaryon Klaineanum Pierre Extracts

“…The crude extract and the isolated compounds of this plant were evaluated for their ability to inhibit the 3D7 strain of Plasmodium falciparum and were evaluated to treat liver complaints and to facilitate the production of breast milk [20,21]. Phytochemical studies of A. klaineanum extracts have shown the presence of secondary metabolites with antimalarial properties [22]. As of now, very few authors reported the evaluation of the antioxidant and antiinflammatory activities of the recipe from these plant.…”

Strychnobaillonine, an Unsymmetrical Bisindole Alkaloid with an Unprecedented Skeleton fromStrychnos icajaRoots

“…During previous works on the roots and stem bark of S. icaja , , a minor alkaloid giving a persistent red coloration after spraying with cerium sulfate reagent was identified, but could not be isolated due to a limited amount of the extracts. In a continuation of our search for potential antiplasmodial compounds from Strychnos species, − we reinvestigated the tertiary alkaloids of S. icaja to isolate this minor alkaloid and evaluate its antiplasmodial activity. The targeted alkaloid, named strychnobaillonine ( 1 ), was successively isolated together with sungucine, bisnordihydrotoxiferine, and strychnohexamine ( 2 ), previously isolated from the plant. , Compounds 1 and 2 were tested in vitro against the chloroquine-sensitive 3D7 strain of P. falciparum .…”