Pharmacognostic, Phytochemical, and Multi-Analytical Profiling of the Leaves and Fruit of Terminalia Catappa L Integrated with In-Silico Docking Studies

Abstract

Background

Terminalia catappa L (Indian almond), a tropical medicinal tree, has traditionally been used for its therapeutic properties. Despite its ethnopharmacological relevance, comprehensive validation of its bioactive constituents and pharmacological potential remains underexplored.

Objective

This study aimed to evaluate the pharmacological, physicochemical, phytochemical, microbial, and metabolomic attributes of T. catappa leaves and fruits, along with in silico docking, to assess its antiepileptic potential.

Methods

Pharmacobotanical studies included macroscopic, microscopic, and physicochemical analyses. Heavy metal and microbial loads were assessed using Atomic Absorption Spectroscopy (AAS). Phytochemical profiling employed Gas Chromatography-Mass Spectrometry (GC-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), and High-Performance Thin Layer Chromatography (HPTLC) to identify bioactive compounds. In silico docking (Schrödinger) targeted epilepsy-related receptors: dopamine (D2), serotonin (5-HT2A), Glutamate- N-methyl-D-aspartate (NMDA), and Gamma-aminobutyric acid (GABA_A).

Results

The medicinal potential of leaves and fruits derived from plants was evaluated through a thorough pharmacognostic and phytochemical analysis. Anatomical studies showed unique characteristics including lignified cells and trichomes. Initial analysis of phytochemicals revealed the presence of cardiac glycosides, flavonoids, and tannins. Using sophisticated analytical methods like LC-MS, important bioactive substances such punicalagin, gallic acid, ellagic acid, and quercetin were found. Their presence was further confirmed by HPTLC analysis, which showed minimal methodological deviation (< 10%) and strong spectral correlation (r = 0.824) for both leaves (ellagic acid: 0.2; gallic acid: 0.881; kaempferol: 0.073; quercetin: 0.3) and fruits (gallic acid: 0.37; ellagic acid: 0.81; rutin: 0.09). The visualisation of phenolic compounds was improved by derivatisation with 1-anilinonaphthalene-8-sulfonic acid (ANS). GC-MS profiling identified 49 phytochemicals in fruits And 42 in leaves, including a variety of terpenoids and phenolics. With the exception of trace amounts of lead (Pb) in fruits, heavy metal analysis verified safety, and microbiological contamination stayed below allowable bounds. According to molecular docking studies, rutin is a strong ligand with a high binding affinity to the NMDA (-6.227 kcal/mol) and dopamine D2 (-8.215 kcal/mol) receptors, suggesting that it has potential antiepileptic properties. The plant’s promise as a source of bioactive chemicals for neurological uses is supported by these findings.

Conclusion

A Rich bioactive substances were identified in the leaves and fruits of Terminalia catappa, with rutin demonstrating great neuroprotective potential by binding to NMDA and dopamine D2. These results provide credence to its application in the development of neurotherapeutics and nutraceuticals.

Graphical Abstract