Phytochemical profiling, fatty acids composition and antioxidant potential of oyster nut (Telfairia pedata) oil

Oyster nut (Telfairia pedata (Sims) Hook) is a nutrient-dense nut widely consumed in East Africa, particularly among lactating mothers, due to its reported lactogenic properties. Its nutritional and phytochemical composition is influenced by ecological conditions, which may affect its ethnopharmacological potential. This study evaluated the phytochemical profile, fatty acid composition, and antioxidant activity of Oyster nut oil obtained from Njombe, Tanzania. Gas chromatography–mass spectrometry (GC–MS) was employed to identify bioactive compounds, while fatty acid composition was determined using Fourier-transform near-infrared spectroscopy (FT-NIR). Antioxidant activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide scavenging assays. GC–MS analysis revealed the presence of seven compounds: 1-isopropylidene-4-methylcyclohexane, oct-5-en-2-yn-4-ol, 3,7,11,15-Tetramethyl-hexadeca-2,6,10,14-tetraen-1-ol, 4-Allyl-2,6-dimethoxy-phenol, 4-Hydroxy-3,5-dimethoxy-benzaldehyde, elemicin and squalene. Among these, only squalene has previously been reported in Oyster nut; the remaining are reported here for the first time. The oil was composed of a high proportion of unsaturated fatty acids (54.7%) while the saturated fatty acids constituted (45.3%). This overall fatty acid composition of the oil was dominated by linoleic acid (45.6%), followed by palmitic acid (32.4%), stearic acid (13.2%), oleic acid (8.5%), and linolenic acid (0.3%). Antioxidant assays demonstrated concentration-dependent activity, with the half-maximal inhibitory concentration (IC₅₀) values of 12.99 µg/mL (DPPH) and 99.40 µg/mL (H₂O₂), higher than that of ascorbic acid (11.39 µg/mL). These findings highlight the potential of Oyster nut oil as a functional food with promising health-promoting properties.