Search for antiprotozoal activity in herbal medicinal preparations; new natural leads against neglected tropical diseases

Llurba Montesino N, Kaiser M, Brun R, Schmidt TJ

Abstract

Sleeping sickness, Chagas disease, Leishmaniasis and Malaria are infectious diseases caused by unicellular eukaryotic parasites ("protozoans"). The three first-mentioned are classified as Neglected Tropical Diseases (NTDs) by the World Health Organization and together threaten more than one billion of lives worldwide. Due to the lack of research interest besides the high increase of the resistances against the existing old treatments, the search for effective and safe new therapies is urgently required. In view of the large tradition of natural products as sources against infectious diseases [1,2], the aim of the present study is to investigate the potential of legally approved and marketed herbal medicinal products (HMPs) as antiprotozoal agents. 58 extracts from 53 HMPs of the German market were tested by a Multiple-Target-Screening (MTS) against parasites of the genera Leishmania, Trypanosoma and Plasmodium. 16 HMPs showed in vitro activity against at least one of the pathogens (IC50<10µg/mL). Six extracts from preparations of Salvia, Valeriana, Hypericum, Silybum, Arnica und Curcuma exhibited high activity (IC50<2.5µg/mL). They were analytically characterized by UHPLC/ESI-QTOF-MSMS and the activity-guided fractionation of the extracts with the aim to isolate and identify the active compounds is in progress.

Projects the publication originates from