In Silico and In Vivo Analysis of the Therapeutic Potential of Zingiber americanus Water Extract

Abstract

Zingiber americanus (Lempuyang Emprit) is a Zingiberaceae plant rich in flavonoids, phenolics, terpenoids, and essential oils, traditionally used for digestive disorders, inflammation, and pain. Analgesics are agents that relieve pain, and the phytochemical profile of this plant suggests it may serve as a promising natural source. For the in-silico study, the principal bioactive constituents of Zingiber americanus identified through LC-HRMS analysis were selected, and their three-dimensional structures were constructed and subjected to energy minimization. The inflammation-associated target protein (PDB ID: 1RWK) was retrieved from the Protein Data Bank, pre-processed by removing native ligands and water molecules, and supplemented with hydrogen atoms to optimize structural stability. Molecular docking simulations were conducted using AutoDock Vina to predict the binding affinities and identify key interacting residues. In addition, pharmacokinetic and drug-likeness properties of the compounds were evaluated using SwissADME to assess their potential suitability as orally active therapeutic agents. The study used male rats divided into five groups: negative control, positive control with meloxicam (50 mg/kg BW), and three treatment groups receiving Zingiber littorale water extract at different concentrations. Analgesic activity was tested using the writhing reflex method, where rats were injected intraperitoneally with acetic acid glacial (1% 5 mL/kg BW) and the number of abdominal constrictions was observed for 30 minutes. The percentage inhibition of writhing was calculated relative to the negative control, and statistical was analysed. 

The molecular docking results showed that the compounds alpinetin and (+)-pinocembrin have the highest affinity for the target receptor with a binding energy of −4.6 kcal/mol, stronger than the natural ligand (−3.9 kcal/mol), through interactions with amino acid residues. Zingiber americanus water extract at doses of 100, 200, and 300 mg/kg BW reduced writhing responses in rats in a dose-dependent manner. The 300 mg/kg BW dose showed the strongest analgesic effect, although it was still lower than meloxicam 50 mg/kg BW.