  Selective Antiprotozoal Activity of Some Strychnos Alkaloids; ; et al in Phytotherapy Research (1994), 8 The in vitro activities of 28 Strychnos alkaloids have been determined against three species of protozoa and the most active compounds were then assessed for in vitro cytotoxic activity against KB cells ... [more ▼] The in vitro activities of 28 Strychnos alkaloids have been determined against three species of protozoa and the most active compounds were then assessed for in vitro cytotoxic activity against KB cells. 3',4'-dihydrousambarensine was the most active against Plasmodium falciparum and was relatively nontoxic to KB cells (cytotoxic/antiplasmodial ratio, 1474). Usambarensine displayed the most selectivity against Entamoeba histolytica while "',4'-dihydrousambarensine was the most selective compound against Giardia intestinalis although the cytotoxic/antiprotozoal ratios (20.4 and 6.6 respectively) were less favourable than the above.The four strychnobiline-type alkaloids were found devoid of activity against E. histolytica and G. intestinalis but to have weak antiplasmodial properties (7-13 times less active than chloroquine). None of the compounds containing only one indole ring system displayed antiprotozoal properties. [less ▲] Detailed reference viewed: 23 (1 ULg)Antiamoebic and Antiplasmodial Activities of Alkaloids Isolated from Strychnos usambarensis; ; et al in Planta Medica (1991), 57 Seven alkaloids isolated from Strychnos usambarensis have been assessed for in vitro activities against Entamoeba histolytica and Plasmodium falciparum and for in vivo activity against Plasmodium berghei ... [more ▼] Seven alkaloids isolated from Strychnos usambarensis have been assessed for in vitro activities against Entamoeba histolytica and Plasmodium falciparum and for in vivo activity against Plasmodium berghei in mice. Strychnopentamine and 3'-4'-dihydrousambarensine were highly active against P. falciparum in vitro, but were inactve and non-toxic against P.berghei in vivo.Usambarensine, usambarine and 18,19-dihydrousambarine were highly active against E. histolytica in vitro, but were less active against P. falciparum in vitro. Nb-methylusambarensine was less active against both protozoa than was usambarensine, and akagerine possessed little antiprotozoal activity.Structure-activity relationships are discussed in the context of the reported cytotoxic and pharmacological properties of those alkaloids. [less ▲] Detailed reference viewed: 23 (6 ULg)A propos des transformations de la strychnine et (à propos des principes actifs) des Strychnos curarisants africainsAngenot, Luc  ; ; et alin Journal de Pharmacie de Belgique (1976), 31(5), 509-510 Strychnine is unstable under light in chloroformic solution and is partly transformed in pseudostrychnine, genostrychnine (Nb-oxy-strychnine) and chloromethostrychninium (a quaternary derivative). In ... [more ▼] Strychnine is unstable under light in chloroformic solution and is partly transformed in pseudostrychnine, genostrychnine (Nb-oxy-strychnine) and chloromethostrychninium (a quaternary derivative). In other respects the curarizing activity of African Strychnos (e.g. Strychnos usambarensis) is not due to isostrychnine as erroneously written by TURKOVIC (J.Pharm Belg. 1976, 31, 277-286) but to quaternary alkaloids like C-dihydrotoxiferine, C-curarine, afrocurarine and C-calebassine (cf L.ANGENOT et al. Arch. Intern. Pharmacodyn. Ther. 1975, 215, 246-258). [less ▲] Detailed reference viewed: 28 (3 ULg) |
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