FTIR Analysis of Aquilaria malaccensis Plant and Callus Extracts Obtained with Various Extraction Fluids

Abstract

Aquilaria malaccensis, a highly endangered species valued for its fragrant resin, faces significant threats from over-harvesting. This study presents a conservation-oriented method for producing agarwood metabolites using a standardized in vitro callus proliferation protocol and solvent-based FTIR spectral profiling. FTIR analysis identified functional groups in ethanol, methanol, ethyl acetate, acetone, and petroleum ether extracts from both in vivo plants and in vitro callus. Callus extracts exhibited higher intensity and a greater diversity of sesquiterpenoidrelated functional groups. Ethanolic and methanolic extracts from both sources exhibited strong O–H and N–H stretches (3366 and 3400 cm^–1), while callus extracts displayed unique peaks such as C=O (1076 cm^–1), C=N (1076 cm^–1), and C=C=C (1956 cm^–1), indicating oxidized and nitrogenous sesquiterpenoids. Ethyl acetate and petroleum ether extracts demonstrated strong C–H stretching and bending vibrations at 2920, 1460, and 778 cm^–1, characteristic of long hydrocarbon chains in resinous compounds. Notably, ethyl acetate extracts from callus also indicated nitrogenous and aromatic sesquiterpenoids. Acetone extracts revealed aromatic and aminerelated peaks at 1509, 1400, and 1056 cm^–1. These findings highlight the enhanced biosynthetic potential of callus cultures. This approach reduces reliance on wild populations, preserves the product's biochemical integrity, and offers an eco-friendly alternative for pharmaceutical applications.