CHEMICAL PROFILING OF CAJANUS CAJAN SEED ETHANOL EXTRACT USING POLARITY-BASED FRACTIONATION.

Abstract Methods : Ethanol extract from C. cajan seeds (400 g; crude extract 9.58 g) was dispersed in water and partitioned sequentially with n-hexane, ethyl acetate, and dichloromethane (100 mL × 3 each), yielding n-hexane (1.2115 g), ethyl acetate (1.8224 g), dichloromethane (1.4314 g), and aqueous (2.6188 g) fractions. TLC profiling was performed using chloroform/methanol (9:1) and hexane/chloroform (9:1) with UV visualization (256–266 nm) and Rf determination. ATR-FTIR spectra were recorded for aqueous, ethyl acetate, and dichloromethane fractions to infer dominant functional groups. GC–MS (EI, 70 eV) was used to profile the n-hexane fraction. HPLC employed external calibration (mixed standards; 20–100 µg/mL) under isocratic (Method A) and gradient (Method B) conditions for identification and quantification. Results : The crude ethanol extract yield was 2.40% (9.58 g/400 g). Fraction yields relative to seed mass were aqueous 0.65%, ethyl acetate 0.46%, dichloromethane 0.36%, and n-hexane 0.30%. TLC (chloroform/methanol 9:1) showed four UV-active spots for the ethyl acetate fraction (Rf 0.640, 0.681, 0.855, 0.913), two spots for n-hexane (Rf 0.860, 0.887), one spot for crude extract (Rf 0.905), and no detectable spot for the aqueous fraction under the stated conditions. FTIR suggested hydroxyl/carbonyl-associated features in the aqueous fraction, amine/carbonyl-related signals in the ethyl acetate fraction, and aromatic/phenolic features in the dichloromethane fraction. GC–MS of the n-hexane fraction identified nine compounds dominated by fatty-acid-related constituents; major components were octadecanoic acid (32.36%), 9,12-octadecadienoic acid (Z,Z) (29.23%), and linoelaidic acid (25.31%) (total oil content 98.85%). HPLC quantified gallic acid (221.609 µg/mL), magnoflorine (175.236 µg/mL), rutin (169.705 µg/mL), and pinostrobin (90.525 µg/mL), with calibration linearity (R² ≥ 0.9).