Improved biopharmaceutical attributes of lumefantrine using choline mimicking drug delivery system: preclinical investigation on NK-65 P.berghei murine model

Exploring the efficacy of ethnomedicinal plants of Himalayan region against the malaria parasite

ETHNOPHARMACOLOGICAL RELEVANCE

Plasmodium falciparum multi-drug resistant (MDR) strains are a great challenge to global health care. This predicament implies the urgent need to discover novel antimalarial drugs candidate from alternative natural sources. The Himalaya constitute a rich repository of medicinal plants which have been used traditionally in the folklore medicine since ages and having no scientific evidence for their activity. Crambe kotschyana Boiss. and Eremurus himalaicus Baker are used for their antipyretic and hepatoprotective properties in Kinnaur district of Himachal Pradesh, India.

AIM OF THE STUDY

This study would investigate the antiplasmodial efficacy of C. kotschyana and E. himalaicus extracts, their fractions and active components using in vitro, in vivo and in silico approaches to provide a scientific insight into their activity.

METHODS

The methanol extracts of C. kotschyana (CKME) and E. himalaicus (EHME) were prepared by maceration followed by fractionation using ethyl acetate. The isolation of flavonoid glycosides isorhamnetin-3, 7-di-O-glucoside from C. kotschyana and luteolin-6-C-glucoside (isoorientin) from E. himalaicus was carried out by antiplasmodial activity-guided isolation. In vitro antimalarial activity was assessed by WHO method while in vitro cytotoxicity was ascertained employing the MTT assay. Molecular docking and molecular dynamics simulation were performed using the Glide module of Schrödinger Software and Gromacs-2022 software package respectively. In vivo curative activity was assessed by Ryley and Peters method.

RESULTS

The methanol extracts of both the plants illustrated the best antiplasmodial activity followed by the ethyl acetate fractions. Iso-orientin (IC50 6.49 μg/ml) and Isorhamnetin-3,7-di-O-glucoside (IC50 9.22 μg/ml) illustrated considerable in vitro activity even against P. falciparum resistant strain. Extracts/fractions as well as the isolated compounds were found to be non-toxic with CC50 > 640 μg/ml. Molecular docking studies were performed with these 2 O-glucosides against four malaria targets to understand the binding pose of these molecules and the results suggested that these molecules have selectivity for lactate dehydrogenase enzyme. CKME and EHME exhibited curative activity in vivo along with increase in Mean Survival Time of mice.

CONCLUSION

The research delineated the scientific evidence that both the therapeutic herbs possessed antimalarial activity and notably, bioactive compounds responsible to exhibit the antimalarial activity have been isolated, identified and characterized. Further studies are underway to assess the antiplasmodial efficacy of isolated compounds alone and in combination with standard antimalarials.

Development and Characterization of Novel Chitosan-Coated Curcumin Nanophytosomes for Treating Drug-Resistant Malaria

This study aimed at enhancing the efficacy of curcumin (CR) by formulating and coating it with chitosan. In silico molecular docking studies revealed that CR exhibited almost similar and low binding energies when compared to artemisinin, indicating high stability at the target site. It can be confirmed that CR is effective in treating and reducing Plasmodium falciparum parasites. Fourier transform infrared studies confirmed that there was a shift and disappearance of some drug peaks in the formulation which revealed complexation with phospholipids. The F2EXT3-developed formulation exhibited greater solubility (24.31 ± 3.47 μg/mL) when compared to pure CR (7.99 ± 1.95 μg/mL). Proton nuclear magnetic resonance studies confirmed the formation of Curcumin-phospholipid hydrogen bonding in F2EXT3. The in vitro drug release studies revealed that the developed formulation F2EXT3 exhibited better drug release at 71.98% at 48 h; this might be due to the effective entrapment efficiency of the drug inside the phospholipid, presence of polyethylene glycol 4000 and chitosan further assisted in sustained release of the drug. Scanning electron microscopy studies revealed that optimized F2EXT3 CR nanophytosomes were nearly spherical with narrow size distribution and smooth surface. The zeta potential of the F2EXT3 showed -3.5 mV. Stability studies revealed that the formulation remained stable even after 6 months. It was observed from the hemin assay that CR and F2EXT3 exhibited (50 μg/mL curcumin) exhibited IC50 values of 47 ± 2.45 and 22 ± 1.58 μM, respectively. Further in vivo antimalarial activity on resistant and sensitive strains needs to be performed to evaluate the efficacy of the developed formulation.

Potential of nanoformulations in malaria treatment

Malaria is caused by the protozoan Plasmodium sp and affects millions of people worldwide. Its clinical form ranges from asymptomatic to potentially fatal and severe. Current treatments include single drugs such as chloroquine, lumefantrine, primaquine, or in combination with artemisinin or its derivatives. Resistance to antimalarial drugs has increased; therefore, there is an urgent need to diversify therapeutic approaches. The disease cycle is influenced by biological, social, and anthropological factors. This longevity and complexity contributes to the records of drug resistance, where further studies and proposals for new therapeutic formulations are needed for successful treatment of malaria. Nanotechnology is promising for drug development. Preclinical formulations with antimalarial agents have shown positive results, but only a few have progressed to clinical phase. Therefore, studies focusing on the development and evaluation of antimalarial formulations should be encouraged because of their enormous therapeutic potential.