In silico to In vivo development of a polyherbal against Haemonchus contortus

Abstract

Haemonchus contortus is a major constraint in the development of small ruminant subsector due to significant production losses incurred by it. The present study explores the antiparasitic potential of three anthelmintic plants ( Butea monosperma, Vitex negundo and Catharanthus roseus (L.) G.Don ) against H . contortus taking albendazole as the standard. In silico molecular docking and pharmacokinetic prediction studies were conducted with known bioactive molecules of these plants (palasonin, vinblastine, vincristine, betulinic acid and ursolic acid) against Glutamate Dehydrogenase (GDH) and tubulin molecules of the parasite. Methanolic extracts of these herbs were fractionated (hexane, ethyl acetate, chloroform and methanol) and used in in vitro larvicidal studies. Based on the in vitro data, two herbal prototypes were developed and clinically tested. All the 5 ligand molecules showed better binding affnity for GDH and tubulin protein as compared with albendazole and shared similar binding site in the core of the GDH hexamer with slight variations. Albendazole approximately stacked against GLY190A residue, showing hydrophobic interactions with PRO157A and a Pi-cation electrostatic interaction with ARG390 along with four hydrogen bonds. Vincristine formed 2 pi-anionic electrostatic bonds with ASP158 of B and C subunits alongwith hydrogen bonding and hydrophobic interaction and an additional pi-anion electrostatic interaction at ASP158A for vinblastine. Albendazole bound to α-tubulin next to colchicine site whereas vinblastine is bound at the nearby laulimalide/peloruside site of the dimer. Betulinic acid showed lateral interaction between the H2–H3 loop of one alpha subunit and H10 of the adjacent alpha subunit of two tubulin dimers. Ursolic acid and palasonin bound at the intradimer N site of microtubulin involving the H1–H7 and H1–H2 zone, respectively. The in vitro studies demonstrated good dose dependent anthelmintic potential. Both the prototypes were quite efficacious in clearing the infection, keeping it to a minimal for more than 5 months, probably, through direct anthelmintic effect through GDH, tubulin depolymerization and uncoupling as well as indirectly through immunomodulation along with antioxidant and anti-inflammatory properties.

Crystal structure of Trichinella spiralis calreticulin and the structural basis of its complement evasion mechanism involving C1q

“…Sequence alignment between TsCRT and other four helminth-produced CRTs, namely, H. contortus calreticulin (HcCRT), N. americanus calreticulin (NaCRT), B. malayi calreticulin (BmCRT), and O. viverrini calreticulin (OvCRT)—which also participate in complement evasion through interacting with C1q ( 21 , 47 , 48 )—revealed that seven of eight key residues are conserved in all helminth CRTs ( Supplementary Figure S3 ). Coincidently, the Yadav group analyzed a docking model of BmCRT binding to C1q, using a predicted structure model, from which 37 residues were considered to be involved in the interaction with C1q; 20 of them being on the N-domain, including the eight conserved key residues identified on TsCRT △ ( 20 ).…”

Importance of conserving Vitex peduncularis: A depleting forest resource with immense ethnopharmacological uses

“…V. trifolia L [75,76,77,78,79] . and V. agnus-castus L. [80,81,82,83,84] are reported to have medicinal uses against several health issues. Numerous phytochemicals that were extracted from V. peduncularis have been studied for their potential as analgesic [85] , antiinflammatory [14] , sedative, antioxidant, anxiolytic antinociceptive, anthelmintic [24] , and antibacterial [86,9] activities.…”