Isolation and In Vitro and In Vivo Activity of Secondary Metabolites from Clerodendrum polycephalum Baker against Plasmodium Malaria Parasites.

Chemical investigation of the antimalarial medicinal plant Clerodendrum polycephalum led to the isolation of five new diterpenoids, including ajugarins VII-X (1-4) and teuvincenone K (5), along with four known compounds, namely, 12,16-epoxy-6,11,14,17-tetrahydroxy-17(15 → 16)-abeo-5,8,11,13,15-abietapentaen-7-one (6), methyl pheophorbide A (7), loliolide (8), and acacetin (9). The chemical structures of the new compounds were elucidated using NMR spectroscopy, mass spectrometry, circular dichroism, as well as density functional theory calculations. All compounds were evaluated for in vitro activity against Plasmodium falciparum 3D7 malaria parasites with methyl pheophorbide A (7) showing the strongest activity (IC50 4.49 µM). Subsequent in vivo testing in a Plasmodium berghei chemosuppression model showed that compound 7 significantly attenuated peripheral blood parasitemia, leading to 79% and 87% chemosuppression following oral doses at 10 and 20 mg/kg, respectively.

Larvicidal Activity of Some Plants Extracts and Their Partitioned Fractions against Culex quinquefasciatus

Aim:The methanol extracts of fifteen plants and their partitioned fractions were screened for larvicidal activity against the fourth instar of larvae Culex quinquefasciatus, the vector of lymphatic filariasiswith a view to identifying the active ones.Methodology:The plant parts were collected,separatelydried and milled. Each powdered material was extracted in methanol at room temperature for 3 days, with agitation. The extract was filtered and concentrated in vacuo. Each extract was tested against the fourth instar larvae of Cx. quinquefasciatus. The methanol extracts were suspended in water and successively partitioned into n-hexane and ethylacetate. Each partitioned fraction was also tested against the fourth instarlarvae of Cx. quinquefasciatus.Results:About fifty six percent (56.3%) of the tested extracts had moderate larvicidal activity after 48 hours. The fruitextract of Thevetia neriifoliaand the leaf extracts of Calotropis procera andOriginal Research Article Solanum macrocarpon were the most active. After partitioning the methanol extracts, each of the plant extracts had one or two highly active partitioned fractions after 48 hours. The n-hexane fractions of S. macrocarpon(0.78 ± 0.03 mg/mL) and Spondias mombin(0.81 ± 0.03 mg/mL) were the most active.Conclusion:The non-polar fractions of S. macrocarponand S. mombinwere the most active. Purification of these highly active fractions could lead to the isolation of potent larvicidal compounds that could be used in the control of Cx. quinquefasciatus mosquito