ferruginol and Malaria

Malaria is a life threatening disease caused by microscopic parasites called Plasmodium that are transmitted to human beings by mosquitoes. Single celled Eukaryotic plasmodium parasite is responsible to cause malaria in human beings and is transmitted by bite of Anopheles species mosquitoes. Resurgence of malaria towards the end of 20th Century is due to failure of its eradication completely. Parasite recurrence occurs due to high densities of parasite, low immunity and non opimized drug concentration. The ineffective eradications strategies were due to indefinable complex life cycle of Plasmodium and emergence of drugs resistant strains of Plasmodium falciparum (Pf) including Artemisinin and Artemisinin based combination therapy (ACT). The vector of the disease i.e. mosquitoes became resistive towards Pyrethroids, which are only class of insecticides recommended for vector control. Artemisinin based combination therapy gained acceptance as an effective approach to counter the spread of disease resistance to chloroquine, sulfadoxine, pyrimethamine and other anti malarial drugs. Understanding the underlying molecular basis of the pathogenesis led to the development of some new diagnostic, drugs and insecticides. Reports on the use of new combination therapies reduced the burden of disease worldwide. Some of the new combination therapies are in clinical stage of development that have efficacy against drug resistant parasites and the potential to use in single dose regimens to improve compliance. The current review represents the recent anti-malarial research carried out globally especially in the class of synthesis of small molecule and natural product derivatives as potent anti-malarial drugs. The review also covers the advancement in the anti-malarial vaccine development although goal for vaccine development still remains elusive.

Topics: Animals; Antimalarials; Artemisinins; Drug Resistance; Humans; Malaria; Plasmodium falciparum

In our previous study, we reported the interesting in vitro antiplasmodial activity of some Rwandan plant extracts. This gave rise to the need for these extracts to also be evaluated in vivo and to identify the compounds responsible for their antiplasmodial activity. The aim of our study was, on the one hand, to evaluate the antiplasmodial activity in vivo and the safety of the selected Rwandan medicinal plants used in the treatment of malaria, with the objective of promoting the development of improved traditional medicines and, on the other hand, to identify the active ingredients in the plants. Plant extracts were selected according to their selectivity index. The in vivo antiplasmodial activity of aqueous, methanolic, and dichloromethane extracts was then evaluated using the classical 4-day suppressive test on Plasmodium berghei infected mice. The activity of the plant extracts was estimated by measuring the percentage of parasitemia reduction, and the survival of the experimental animals was recorded. A bioguided fractionation was performed for the most promising plants, in terms of antiplasmodial activity, in order to isolate active compounds identified by means of spectroscopic and spectrometric methods. The highest level of antiplasmodial activity was observed with the methanolic extract of Fuerstia africana (> 70 %) on days 4 and 7 post-treatment after intraperitoneal injection and on day 7 using oral administration. After oral administration, the level of parasitemia reduction observed on day 4 post-infection was 44 % and 37 % with the aqueous extract of Terminalia mollis and Zanthoxylum chalybeum, respectively. However, the Z. chalybeum extract presented a high level of toxicity after intraperitoneal injection, with no animals surviving on day 1 post-treatment. F. africana, on the other hand, was safer with 40 % mouse survival on day 20 post-treatment. Ferruginol is already known as the active ingredient in F. Africana, and ellagic acid (IC50 = 175 ng/mL) and nitidine (IC50 = 77.5 ng/mL) were identified as the main active constituents of T. mollis and Z. chalybeum, respectively. F. africana presented very promising antiplasmodial activity in vivo. Although most of the plants tested showed some level of antiplasmodial activity, some of these plants may be toxic. This study revealed for the first time the role of ellagic acid and nitidine as the main antimalarial compounds in T. mollis and Z. chalybeum, respectively.

Topics: Abietanes; Animals; Antimalarials; Benzophenanthridines; Ellagic Acid; Female; In Vitro Techniques; Lamiaceae; Malaria; Medicine, African Traditional; Mice; Parasitic Sensitivity Tests; Plant Extracts; Plants, Medicinal; Plasmodium berghei; Rwanda; Terminalia; Zanthoxylum