Medicinal plants for in vitro antiplasmodial activities: A systematic review of literature.

The increasing resistance of malaria to drugs raise the need to new antimalarial agents. Antiplasmodial herbs and their active compounds are the most promising source the new antimalarial agents. This study aimed to identify the medicinal plants with very good in vitro antiplasmodial activities, with half-maximal inhibitory concentration (IC)≤1μg/ml, and to determine trends in the process of screening their antiplasmodial activities. A total of 58 reports published in the English language were retrieved from the bibliographical databases. Screening and data extraction were performed by two independent reviewers. The herbs were categorized as very good, good, moderate and inactive if the IC values were <0.1μg/ml, 0.1-1μg/ml, >1-5μg/ml and >5μg/ml respectively. We documented 752 medicinal plants belonging to 254 genera. The majority of the plants were reported from Africa followed by Asia. The traditional use for malaria treatment was the most common reason for the selection of the plants for investigation. About 80% of the plants experimented were reported to be inactive. Among plants identified as having very good to good antiplasmodial crude extracts are Harungana madagascariensis, Quassia africana, and Brucea javanica, while Picrolemma spruce, Aspidosperma vargasi, Aspidosperma desmanthum, and Artemisia annua were reported to have individual compound isolates with very good antiplasmodial activities. In conclusion, the number of plant species assessed so far is still small compared with the stock in nature's plant library. A mechanism of systematically approaching and exploring the untouched plant genera needs to be designed.