Analgesic Profiling of Capsicum Extracts Using the Hot Plate Test in Mice: An Integrative Analysis of Bioactive Compounds Based on FT-IR, GC-MS, and Molecular Docking Studies

Objectives: This study aims to investigate the analgesic potential of extracts from 3 Capsicum species, namely Capsicum chinense (CC), Capsicum frutescens (CF), and Capsicum annuum (CA), using a hot plate test in mice. In addition, the study identified the key bioactive compounds in the extracts through a combined analysis of Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and molecular docking studies. Materials and Methods: During the experimental procedures, extracts from the fruit, stem, and leaves of 3 Capsicum species were prepared using methanol, hexane, and distilled water (aquadest) as solvents. The chemical composition of these extracts was profiled and classified through Fourier-transform infrared (FTIR) spectroscopy combined with cluster analysis. Subsequently, the analgesic activity of the samples was assessed in vivo using the hot plate test in mice. Gas chromatography-mass spectrometry (GC-MS) was used to identify the bioactive compounds present in both the most potent and least potent extracts. Molecular docking studies were then conducted to predict the interactions between these compounds and specific analgesic protein targets, namely 5IKQ, 4TLM, and 4EJ4. Results: The results showed that the aquadest fruit extract of CC had the highest analgesic activity, while extracts from CF and CA had minimal effects. GC-MS analysis showed that the extract with minimal effects contained terpenoids, sterols, vitamins, hydrocarbons, and fatty acids. However, CC was rich in alkaloids capsaicin (4.38%) and dihydrocapsaicin, O-acetyl- (2.26%), terpenoids (nerolidyl acetate) (11.32%), phenolics (2-methoxy-phenol) (1.37%), and fatty acid derivatives. Molecular docking studies confirmed that capsaicin and dihydrocapsaicin, O-acetyl- exhibited strong binding affinities with analgesic protein targets 5IKQ (-8.0 kcal/mol), 4TLM (-5.3 and -4.9 kcal/mol), and 4EJ4 (-7.3 and -6.5 kcal/mol) outperforming the reference drug sodium diclofenac (-8.3, -5.9, and -6.6 kcal/mol). Conclusion: This study described the significant analgesic potential of CC extracts, particularly the aquadest fruit extract, as a promising candidate for developing new pain management therapies.