The search for new antimalarial drugs from plants used to treat fever and malaria or plants ramdomly selected: a review

Abstract

In this review we discuss the ongoing situation of human malaria in the Brazilian Amazon, where it is endemic causing over 610,000 new acute cases yearly, a number which is on the increase. This is partly a result of drug resistant parasites and new antimalarial drugs are urgently needed. The approaches we have used in the search of new drugs during decades are now reviewed and include ethnopharmocology, plants randomly selected, extracts or isolated substances from plants shown to be active against the blood stage parasites in our previous studies. Emphasis is given on the medicinal plant Bidens pilosa, proven to be active against the parasite blood stages in tests using freshly prepared plant extracts. The anti-sporozoite activity of one plant used in the Brazilian endemic area to prevent malaria is also described, the so called "Indian beer" (Ampelozizyphus amazonicus, Rhamnaceae). Freshly prepared extracts from the roots of this plant were totally inactive against blood stage parasites, but active against sporozoites of Plasmodium gallinaceum or the primary exoerythrocytic stages reducing tissue parasitism in inoculated chickens. This result will be of practical importance if confirmed in mammalian malaria. Problems and perspectives in the search for antimalarial drugs are discussed as well as the toxicological and clinical trials to validate some of the active plants for public health use in Brazil

New approaches in antimalarial drug discovery and development: a review

“…The use of GFP sporozoites would be useful in protocols because this approach would allow the parasite route to be followed from the site of inoculation to the liver cells (Gueirard et al 2010), thus elucidating where the parasite is targeted by the antimalarials. The anti-sporozoite activity of two medicinal plants, Ampelozyziphus amazonicus and Strychnopsis thouarsii, has been demonstrated; these drugs were used in malaria-endemic areas of Brazil (AndradeNeto et al 2008, Krettli et al 2001 and Madagascar (Carraz et al 2006), as discussed below.…”

“…1B) (Krettli et al 2001). A. amazonicus was the most cited plant species in recent ethnobotanical surveys in the state of Amazonas (AM) ).…”

In vitro inhibition of Plasmodium falciparum by substances isolated from Amazonian antimalarial plants

“…The rational search for active substances in medicinal plants is a very promising and cost-effective strategy for antimalarial drug discovery. This approach benefits from the accumulated knowledge of the curing capacity of plants possessed by inhabitants of malaria endemic regions and permits the extensive evaluation of natural products derived from these sources (Campbell et al 1997, 1998, Brandão et al 1992, 1997, Krettli et al 2001, Andrade-Neto et al 2004a.…”

“…The rational search for active substances in medicinal plants is a very promising and cost-effective strategy for antimalarial drug discovery. This approach benefits from the accumulated knowledge of the curing capacity of plants possessed by inhabitants of malaria endemic regions and permits the extensive evaluation of natural products derived from these sources (Campbell et al 1997, 1998, Brandão et al 1992, 1997, Krettli et al 2001, Andrade-Neto et al 2004a.This triage of useful and effective plants is at the heart of traditional medicinal knowledge and is an extremely important source of therapeutic compounds in use today. Important semi-synthetic, low-cost, highly effective antimalarial drugs such as the quinolines (chloroquine, mefloquine, primaquine, etc.)…”

Atribuição dos deslocamentos químicos dos átomos de ¹H e 13C do acetato de acantoaustralida

“…Foi constatado por e por Krettli et al (2001), que o extrato bruto de Acanthospermum australe foi parcialmente ativo contra Plasmodium falciparum em ratos infectados. Em 1997, Macedo et al(1997 (Debenedetti et al1987;Shimizu et al 1987) e 6-metoxi fl avonóides (Debenedettis et al, 1987).…”