Planta Med 2023; 89(14): 1317-1318
DOI: 10.1055/s-0043-1773938
Abstracts
Monday 3rd July 2023 | Poster Session I
Phytochemistry I – General

Antiprotozoal activity of alkaloid fractions and isolation of a new megastigmane alkaloid from leaves of Pachysandra terminalis

Lizanne Schäfer
1   Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of Münster, PharmaCampus, Münster, Germany
,
Marcel Kaiser
,
Pascal Mäser
,
Thomas J. Schmidt
1   Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of Münster, PharmaCampus, Münster, Germany
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    Trypanosoma brucei rhodesiense (Tbr) and Plasmodium falciparum (Pf) are protozoan parasites that cause severe diseases namely human African trypanosomiasis and Malaria. As there are limited treatment options and with occurring resistances there is the compelling need for new antiprotozoal compounds. Previous studies have already shown that plants belonging to the family of Buxaceae contain aminosteroids with high activities against these parasites. The alkaloid enriched fraction of Pachysandra terminalis (Buxaceae) also showed prominent activity against Tbr. It is therefore promising to further examine the constituents of this plant and systematically isolate single compounds. An optimised extraction protocol was established to receive an alkaloid enriched fraction that was active against Tbr (IC50 1.84 µg/mL) and especially highly active against Pf (IC50 0.31 µg/mL). The alkaloid enriched fraction was separated into 18 subfractions using centrifugal partition chromatography (CPC). Each of these subfractions showed strong activity against Pf and some of them were also active against Tbr. From one of these fractions a megastigmane alkaloid ([Fig. 1]) could be isolated, which, to the best of our knowledge, is a new natural product. The structure elucidation was accomplished by UHPLC/+ESI-QqTOF-MS/MS, NMR and CD-Spectroscopy. This compound did not show a high activity against Tbr (IC50 6.22 µg/mL). Its activity against Pf was higher (IC50 0.93 µg/mL), but it is not mainly responsible for the high activity of the alkaloid fraction. Therefore, systematic search for and isolation of the compounds responsible for the activity of P. terminalis is now in progress.

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    Fig. 1 Megastigmane alkaloid isolated from Pachysandra terminalis. The compound exists as a mixture of the R- and S-isomers at C-4. The configuration at C-9 is still under investigation.

     

    Publication History

    Article published online:
    16 November 2023

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    Fig. 1 Megastigmane alkaloid isolated from Pachysandra terminalis. The compound exists as a mixture of the R- and S-isomers at C-4. The configuration at C-9 is still under investigation.