GC-MS PROFILING, PHYSICOCHEMICAL CHARACTERIZATION, NMR SPECTROSCOPY AND ANTIBACTERIAL ACTIVITY OF ANACARDIUM OCCIDENTALE L. SEED OIL

This study characterized seed oil from Anacardium occidentale L. using physicochemical measurements, gas chromatography–mass spectrometry (GC-MS), proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR) spectroscopy, and antibacterial screening. The oil had an acid value of 5.4 ± 0.6 mg KOH/g, saponification value of 187.4 ± 2.7 mg KOH/g, iodine value of 78.9 ± 1.5 g I2/100 g, peroxide value of 6.0 ± 1.2 meq O2/kg, specific gravity of 0.96 ± 0.13 and refractive index of 1.481 ± 0.01 at 40°C. GC-MS profiling demonstrated a complex lipid composition comprising saturated and monounsaturated fatty-acid methyl esters together with minor phenolic, sterol and triterpenoid constituents. Prominent assignments included methyl palmitate (10.153%), methyl 6-octadecenoate (9.9453%), methyl cis-11-eicosenoate (5.0128%), methyl stearate (7.4483%) and methyl oleate. The dataset also contained phenolic lipids, 2-hydroxy-1-(hydroxymethyl)ethyl oleate, squalene, γ-sitosterol and β-amyrin. The 1H and 13C NMR spectra were consistent with a lipid-rich matrix containing long-chain aliphatic, olefinic, glycerol and ester-carbonyl environments. Antibacterial screening showed the greatest inhibition against Pseudomonas syringae (12.50 ± 1.32 mm), followed by Ralstonia solanacearum (6.50 ± 1.67 mm). The results indicate that A. occidentale seed oil is a chemically diverse plant lipid with potential nutritional, oleochemical and biological relevance.