The in vitro antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A1, was investigated on Leishmania infantum. The assessment of possible targets (membrane integrity, membrane potential, DNA synthesis and protein content) was performed in both Leishmania promastigotes and human monocytes (THP1 cells). Results observed in Leishmania showed that the saponins exhibited a strong antiproliferative activity on all stages of development of the parasite by altering membrane integrity and potential: hederacolchiside A1 appeared to be the most active compound against both promastigotes and amastigotes. Results observed in THP1 cells demonstrated that the saponins exerted also a potent antiproliferative activity against human monocytes, by producing a significant DNA synthesis inhibition. The ratio between antileishmanial activity on amastigotes and toxicity to human cells suggested that the saponins could be considered as possible antileishmanial drugs.

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The in vitro antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A(1), was investigated on parasites of the species Leishmania mexicana, in their promastigote and amastigote forms compared with their toxicity versus human monocytes. The results showed that saponins exhibited a strong antiproliferative activity on all stages of development of the parasite but demonstrated a strong toxicity versus human cells. Association of subtoxic concentrations of saponins with antileishmanial drugs such as pentamidine and amphotericin B demonstrated that saponins could enhance the efficiency of conventional drugs on both the promastigote and the amastigote stages of development of the parasite. The results demonstrated moreover that the action of saponins on promastigote membrane was cumulative with those of amphotericin B.

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Of the seven triterpene glycosides present in the leaves of Hedera colchica C. Koch, (ram. Araliaceae) -Colchis ivy, which we have called hederacolchisides, we have previously isolated and characterized the three most polar [i, 2]. In continuation of these investigations, we have succeeded in isolating another three, comparatively nonpolar, compounds present in the total in minor amount -hederacolchisides A', A, and C.Complete acid hydrolysis showed that glycosides A' and C, with mp 222-226 and 168-176°C (decomp.), respectively, were derivatives of oleanolic acid, while glycoside A, with mp ±68-176°C (decomp.), was a hederagenin derivative. By PC and TLC, and by the GLC of the monosaccharides in the form of their polyol acetates on a Chrom-5 instrument [3], it was establishedthat the carbohydrate moieties of hederacolchisides A' and A contained rhamnose, arabinose, and glucose residues in a ratio of i:i:i, and that of hederacolchiside C contained the same residues in a ratio of 2:1:2.According to the results of UR spectroscopy and alkaline hydrolysis, in glycosides A' and A the monosaccharides were attached in position 3 of the aglycons, while in glycoside C an ester bond was found, in addition.The determination of the complete chemical structures of the glycosides isolated is continuing.