Abstract
Background and Aim: The increasing prevalence of drug-resistant fungal, malarial, and helminth infections necessitates the identification of novel, broad-spectrum therapeutic agents. Alstonia scholaris, widely used in Mizo traditional medicine, has been reported for treating microbial and parasitic infections. This study aimed to evaluate the multifaceted anti-infective efficacy of a geographically distinct Mizoram chemotype of A. scholaris through in vitro assays and molecular docking analyses.
Materials and Methods: Methanolic bark extract of A. scholaris was assessed for antifungal activity against Aspergillus fumigatus, Candida albicans, and Neocosmospora keratoplastica using the agar poison technique. Antimalarial activity was tested against chloroquine-sensitive (3D7) and multidrug-resistant (K1) strains of Plasmodium falciparum using a SYBR Green I-based fluorescence assay. Cytotoxicity was evaluated in Vero C1008 cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Anthelmintic efficacy was determined against Raillietina echinobothrida using histological and scanning electron microscopy analyses. Bioactive compounds were identified by gas chromatography-mass spectrometry (GC-MS), followed by molecular docking against key pathogen targets.
Results: The extract demonstrated significant antifungal activity, with N. keratoplastica being the most susceptible species. Antimalarial activity showed comparable efficacy against both P. falciparum strains, with IC50 values of 43.40 μg/mL (3D7) and 45.60 μg/mL (K1), and a low resistance index of 1.05. Cytotoxicity analysis indicated high CC50 (>100 μg/mL), suggesting safety, although selectivity indices were moderate. Anthelmintic activity revealed concentration-dependent effects, comparable to albendazole (p > 0.05). Histological and ultrastructural analyses confirmed severe tegumental and internal tissue damage in parasites. GC-MS identified triterpenoids, predominantly α-amyrin and kolavenol. Docking studies revealed strong binding affinities of α-amyrin with fungal sterol 14α-demethylase (CYP51, at 10.4 kcal/mol), malarial S-adenosyl-L-homocysteine hydrolase (SAHH, at 10.0 kcal/mol), and helminth glutamate-gated chloride channel (GluCl, at −9.4 kcal/mol), supporting multi-target activity.
Conclusion: The Mizoram chemotype of A. scholaris exhibits broad-spectrum anti-infective potential with antifungal, antimalarial, and anthelmintic activities. The predominance of triterpenoids, particularly α-amyrin and kolavenol, distinguishes it from other chemotypes and underpins its pharmacological profile. These findings validate its traditional use and highlight its potential as a source of novel anti-infective agents, warranting further in vivo and mechanistic studies.
Keywords: anthelmintic, antifungal, antimalarial, drug resistance, medicinal plant, molecular docking, parasite, triterpenoids.