FTIR and UV-Visible Spectroscopic Analysis of Gmelina arborea Leaf Extract

Abstract

The present study provides the spectroscopic characterization of Gmelina arborea leaf utilizing Fourier Transform Infrared (FTIR) spectroscopy and UV-Visible spectrophotometry to understand the phytochemical elements and optical characteristics of the plant material. FTIR analysis, performed on a Shimadzu instrument, revealed nine characteristic absorption peaks in the range of 524–3378 cm⁻¹. The broad absorption band at 3378.47 cm⁻¹ is attributed to O–H stretching vibrations, indicating the presence of hydroxyl functional groups associated with phenols and alcohols. The peak at 2924.21 cm⁻¹ corresponds to C–H stretching of aliphatic hydrocarbons, while the notable peak at 2139.15 cm⁻¹ suggests the presence of C≡C or C=C=O stretching, indicative of alkynes or cumulated dienes. Peaks observed at 1631.85 cm⁻¹ and 1389.77 cm⁻¹ are associated with C=C aromatic stretching and C–H bending vibrations, respectively. Absorption bands at 1249.93 cm⁻¹ and 1091.76 cm⁻¹ confirm C–O stretching, suggesting the presence of ethers, esters, or polysaccharides. The fingerprint region peaks at 634.61 cm⁻¹ and 524.66 cm⁻¹ indicate C–X (halogen) or skeletal bending vibrations. UV-Visible spectral analysis conducted over the wavelength range of 200–1100 nm demonstrated complex and broad-spectrum absorbance patterns with multiple high-intensity absorption bands (absorbance up to ~7), particularly prominent in the 300–1000 nm region. The highly oscillatory absorbance profile suggests the presence of diverse chromophoric groups including flavonoids, terpenoids, tannins, and chlorophyll-related pigments. Collectively, the spectroscopic data confirm that Gmelina arborea leaf is rich in bioactive phytochemicals with diverse functional groups, supporting its ethnopharmacological significance and potential for further biological and pharmacological investigations.