K. KUMAR JAVARAPPA*#, SANKEERTHANA RENUKA PRASAD*, P. MALLIKARJUNA SWAMY**, A. PANCHAKSHARI*
*University Sophisticated Instrumentation Centre (USIC), JSS Academy of Higher Education and Research (JSS AHER), Mysuru, Karnataka, Indi#e-mail: komalkumar@jssuni.edu.in
**Division of Biochemistry, School of Life Sciences, JSS Academy of Higher Education and research, SS Nagar, Mysuru 570015, India
The biochemical profiles of five chosen medicinal plant leaves in both fresh and shade-dried forms were analyzed using attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spectroscopy. Major functional groups were identified, spectral variations between the medicinal plants were assessed, and the impact of drying on functional groups was analyzed. Samples were scanned in the mid-infrared range (4000–400 cm⁻¹), and spectra were processed using baseline correction, normalization, and averaging among repeats. Prominent absorption bands corresponding to hydroxyl, aliphatic, carbonyl, amide, and carbohydrate functional groups were consistently observed across the analyzed medicinal plants. Fresh samples displayed wide and powerful O–H bands due to greater moisture content, which concealed underlying biomolecular characteristics. Shade-drying considerably decreased water-associated absorptions, increasing the resolution of protein (amide I and amide II), lipid, and polysaccharide bands. The study shows that ATR-FTIR is a quick, non-destructive analytical method that can produce repeatable biochemical fingerprints for therapeutic plants. Furthermore, shade-dried leaves were shown to provide sharper spectral fingerprints than fresh material, indicating their applicability for spectroscopic authentication and phytochemical screening. These findings provide baseline FTIR spectral assignments for the investigated species and show the potential of vibrational spectroscopy for quality control.
Key words: ATR-FTIR, functional groups, medicinal plants, biomolecules, phytochemicals
Corresponding author’s e-mail: komalkumar@jssuni.edu.in