Four New Limonoids from the Barks of Toona ciliata

Antimalarial activity of Toona ciliata MJ Roem aqueous methanolic leaf extract and its antioxidant and phytochemical properties

Background and aim

Malaria is a global health issue causing substantial morbidity and mortality. Screening of various traditionally important medicinal plants is a key source for the discovery of new antimalarials. We evaluated the antimalarial and antioxidant activities, and performed detailed phytochemical analyses of Toona ciliata MJ Roem aqueous methanolic leaf extract (TcMLE).

Experimental procedures

In vitro antiplasmodial studies in Plasmodium falciparum (Pf) 3D7 and PfCam3.IR539T strains were performed by [3H]-hypoxanthine uptake assays. In vitro cytotoxicity in HeLa and HEK293T cell lines was evaluated using MTT assays. Hemolysis assay was performed using RBCs. Phytochemical analysis by GC-MS and in vitro antioxidant studies by DPPH and ABTS assays were performed. In vivo antimalarial studies in Pb-infected mice were carried out using Rane's test and Peters' 4-day test.

Results and conclusions

TcMLE showed significant in vitro antioxidant activity and had phytochemicals reported for antimalarial activity. In vitro studies showed prominent antiplasmodial activity against Pf3D7 strain (IC50 ∼22 μg/ml) and PfCam3. IR539Tstrain (IC50 value ∼43 μg/ml). In vitro cytotoxicity studies, in vitro hemolytic assays, and in vivo acute toxicity studies further suggested that TcMLE is nontoxic. In vivo antimalarial studies using Rane's test showed a significant decrease in parasitemia by ∼70% at 1200 mg/kg doses and delayed the mortality of mice by ∼10-14 days. Peters' 4-day test also showed a similar pattern. The present study demonstrated the antimalarial potential of TcMLE. These findings deliver a platform for further studies to identify the active components of TcMLE and discover new antimalarials.

Research progress of meliaceous limonoids from 2011 to 2021

Covering: July 2010 to December 2021Limonoids, a kind of natural tetranortriterpenoids with diverse skeletons and valuable insecticidal and medicinal bioactivities, are the characteristic metabolites of most plants of the Meliaceae family. The chemistry and bioactivities of meliaceous limonoids are a continuing hot area of natural products research; to date, about 2700 meliaceous limonoids have been identified. In particular, more than 1600, including thirty kinds of novel rearranged skeletons, have been isolated and identified in the past decade due to their wide distribution and abundant content in Meliaceae plants and active biosynthetic pathways. In addition to the discovery of new structures, many positive medicinal bioactivities of meliaceous limonoids have been investigated, and extensive achievements regarding the chemical and biological synthesis have been made. This review summarizes the recent research progress in the discovery of new structures, medicinal and agricultural bioactivities, and chem/biosynthesis of limonoids from the plants of the Meliaceae family during the past decade, with an emphasis on the discovery of limonoids with novel skeletons, the medicinal bioactivities and mechanisms, and chemical synthesis. The structures, origins, and bioactivities of other new limonoids were provided as ESI. Studies published from July 2010 to December 2021 are reviewed, and 482 references are cited.