The Antiplasmodial Activities of Aqueous Extracts of Selected Ghanaian Herbal Plants.

Background: are known to respond differently to antimalarial drugs. Herbal products with extended treatment regimens and inadequate dosing information are widely used to treat malaria in Ghana. This study set out to determine the activity of selected herbal extracts on the development of asexual and sexual stage malaria parasites.

Methods: The 72-hour SYBR Green 1-based drug assay was used to determine the asexual parasite growth inhibitory effects exhibited by aqueous extracts of , , , and on the NF54, CamWT_C580Y, and IPC 4912 strains of . The effects of exposure of asexual and early-stage NF54 gametocytes to varying concentrations of the aqueous herbal extracts were assessed by microscopy after 7 days of continuous culturing in the presence of the herbal extract. Qualitative and quantitative phytochemical screening were also performed on the herbal extracts.

Results: In the SYBR Green 1 assay, aqueous extracts of exhibited moderate (IC of 5.8, 17.4, and 15.8 g/ml) and exhibited low (IC of 65.4, 96.7, and 81.7 g/ml) activities against the NF54, Cam WT_C580Y, and IPC 4912 parasites, respectively, whilst and were inactive. Long-term treatment of NF54 parasites with 1 mg/ml of produced the highest densities of gametocytes and the least (56%) inhibition of asexual parasites on Day 7. Long-term treatment of NF54 parasites with 10 g/ml resulted in complete parasite (asexual and gametocyte) clearance on Day 7. exhibited a 'moderate' activity against the three parasites tested in the 72-hour SYBR Green 1 assay and also effectively cleared both asexual parasites and gametocytes. Long-term treatment of malaria parasites with herbal extracts mimics a treatment regimen and should be used to determine the antimalarial properties of herbal extracts.