Crude extracts and pure compounds evaluations

Bruxelles Woluwe

Plants used in traditional medicine in different countries are obtained through research collaborations (Marocco, Benin, Congo Democratic Republic, Rwanda, Madagascar, Mauritius in Africa, Vietnam in Asia, Peru, Bolivia and Brazil in South America). The first step is the selection on an ethnopharmacological basis and a literature survey. Different extracts are prepared and pharmacologically evaluated according to their traditional use(s). Several properties are analysed in our lab or in collaboration with other teams who developed suitable pharmacological tests (LDRI, other UCL or Belgian partners): in the last years we mainly focused on antimicrobial and antiparasitic activities, but two new projects were developed dealing with immunostimulant and anti-inflammatory activities.

Crude extracts are first evaluated by in vitro tests and their cytoxicity assessed on cancer and non-cancer cell lines.

 

 

 

 

The originality of our works is that we do not just realise screenings. The most promising extracts are also tested in vivo to assess their activity and eventual toxicity. The mode of administration is chosen according to the nature of the extract but most of them are given by oral route. 

Several extracts possessing biological activities at low concentrations in vitro were identified (cfr publications).

The activities of the most interesting ones as well as purified compounds were also analysed in vivo. Acute and sub-acute toxicity tests are realised on rodents or using zebrafish (collaboration with Prof. Frédérich, University of Liège). Results indicate that extracts of Croton zambesicus, Ajuga iva and Marrubium vulgare showed, in vivo, antihypertensive properties but some extracts of Croton zambesicus also showed toxicities. Extracts from i.e. Keetia leucantha, Vitellaria paradoxa and Acanthospermum hispidum as well as isolated triterpenic esters proved to have antimalarial activities on mice infected by Plasmodium berghei.

Efficient extracts and pure compounds on mice infected with Trypanosoma brucei were also identified and their highest tolerated dose determined.

Our works on antimicrobial plants allowed us to identify some promising plant extracts and natural compounds reducing the resistance of methicillin resistant Staphylococcus aureus in vitro (collaboration with F. Van Bambeke) and in vivo (collaboration with Prof. Niset, San Diego, USA). Other collaborations allow us to identify extracts improving fish resistance to microbial infection (collaboration with P. Kestomont, UNamur) or possessing antihelminthic properties for cattle (collaboration with UAC Benin).

Other extracts were shown to reduce the cytokines production of LPS activated macrophages (collaboration with Prof. Muccioli).