Investigation of the antimalarial efficacy of Ilex umbellulata (Wall.) Loes. bark against Plasmodium falciparum using in-vitro whole-cell assays, GC-MS, LC-ToF-MS, and multi-step computational studies.

ETHNOPHARMACOLOGICAL RELEVANCE

Ilex umbellulata (Wall.) Loes. (Family: Aquifoliaceae), widely used by different tribes of Southeast Asia as a herbal remedy. The Mizo tribe in India used the stem bark to treat malaria, gland inflammation, inflammation in pregnant women, tonsillitis, dysentery, and for veterinary purposes to treat pig sickness and mange. In Meghalaya, India, the decocted bark is used for digestion. In Thailand, the raw fruit was consumed to relieve stomach aches.

AIM OF THE STUDY

The study aims to evaluate the in vitro antimalarial efficacy of I. umbellulata bark by screening against chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfRKL-9) strains of Plasmodium falciparum. Also, the study aims to identify the phytocompounds present in the most active extract and explore the molecular mechanisms against P. falciparum and malaria through in silico approaches.

MATERIAL AND METHODS

I. umbellulata bark, collected from Mizoram, India, was taxonomically authenticated by the Botanical Survey of India. Twelve extracts obtained using Soxhlet extraction, decoction, and cold maceration techniques were evaluated for in vitro antimalarial activity against the Pf3D7 and PfRKL-9. Fractions obtained from the active extract were screened for in vitro antimalarial activity. The active extract and fraction were tested for their cytotoxicity using the human embryonic kidney (HEK)-293 cell line and also for their hemolytic activity. The selected extract underwent gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-time of flight (LC-ToF)-MS analyses. Molecular docking, dynamic simulations, and binding free energy calculations were also employed to identify potential targets in P. falciparum. Network pharmacology revealed the malaria pathway genes affected by the phytocompounds of I. umbellulata.

RESULTS

The 80% MeOH extract (IC≤1μg/ml) and the polar fraction (IC≤3μg/ml) showed the best antimalarial activity. Cytotoxicity and hemolysis assays confirmed the safety and selectivity of the active samples. GC-MS and LC-ToF-MS analyses of the 80% MeOH extract detected 15 and 10 phytocompounds, respectively. Molecular docking and dynamic simulations showed that the phytocompounds of I. umbellulata formed stable complexes with 10 blood-stage P. falciparum proteins. The network pharmacology study suggests that I. umbellulata may regulate immune responses, reduce inflammation, support early immune signaling, and prevent vascular complications in malaria.

CONCLUSION

The study identifies 25 phytocompounds in the active extract of I. umbellulata, elucidating their key molecular mechanisms and validating the plant's traditional use, thereby signifying its efficacy and safety for malaria treatment on a global scale.