Study of the antiplasmodial potential of Vernonia fimbrillifera Less. (Asteraceae) leaves, an endemic plant from Reunion Island

According to WHO [1] malaria is still one of the leading public health problems particularly in Sub-Saharan Africa with 240 million cases in 2015. The emergence of drug resistance to available chemotherapeutic agents is worrying. Thus, the need of new antimalarial drugs remains a priority. It is widely admitted that plants represent a major source for the discovery of bioactive agents. Endemic plants from Reunion Island, "hot spot" of biodiversity, are considered as promising potential for new antimalarial compounds identification [2]. The genus Vernonia is well known for its numerous biological activities such as antiparasitic, anti-inflammatory or antioxidant activities [3]. Nevertheless, because of its endemic origin, Vernonia fimbrillifera Less. has never yet been investigated. Preliminary assays showed that dichloromethane crude extract of the leaves possesses high antiplasmodial in vitro activity (IC₅₀ 3, 85 ± 1, 43 µg/ml) against Plasmodium falciparum 3D7 chloroquine-sensitive strain. Thus, the aim of this work is to elucidate the molecules responsible for this activity. A bioguided fractionation has been realized and leads to the isolation of several sesquiterpenic lactones, among which is dehydromelitensin-8-(4'hydroxymethacrylate), previously isolated from Centaurea omphalotricha (Asteraceae) [4]. This compound exhibited antiplasmodial activity in the 1, 5 µg/mL range. In conclusion, this work reveals several sesquiterpenic lactones, identified for the first time in Vernonia fimbrillifera, which are responsible for the antiplasmodial activity of the plant.

Acknowledgements: This work is supported partly by the Regional Council of La Réunion and by the European Regional Development Fund (ERDF). The authors are very grateful to J. Fournel and D. Strasberg (UMR C_53 PVBMT) for their contribution to plant material identification and species collection.

Keywords: Malaria, plasmodium, Vernonia fimbrillifera, endemic plants, Reunion Island.

References:

[1] WHO, World Malaria report 2015

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