Fatty Acid Profile, Characterization and Biological Activities of Oil from Citrus paradisi and Citrus lemon Seeds

Abstract

In this study, C. paradisi and C. lemon seed oils were extracted with five (5) litres of n-hexane using cold extraction method. Characterization of the seed oils were determined using Gas Chromatography-Mass Spectrometry (GCMS), Infrared and Ultraviolet-Visible Spectroscopy. The seed oils of C. paradisi and C. lemon were further examined for antimicrobial and antioxidant activities. Fatty acids were discovered to be abundant in the seed oils of C. paradisi and C. lemon, with cis-linoleic acid accounting for the majority (41.03% and 48.34%, respectively), followed by palmitic acid (27.99% and 16.37%) and oleic acid (21.00% and 22.34%). Stearic acid (2.98% and 3.81%) and α-linolenic acid (4.80% and 3.49%) were also found in trace levels. Key functional groups were identified by FT-IR analysis of the oils. For C. paradisi and C. lemon, they included C=O stretching at 1746 cm⁻¹ and 1744 cm⁻¹, C=C stretching at 1650 cm⁻¹ and 1640 cm⁻¹, C–O stretching at 1238 cm⁻¹ and 1236 cm⁻¹, and O–H stretching at 3424 cm⁻¹ and 3434 cm⁻¹. Both oils had two separate absorption peaks in the UV-Visible spectroscopic result, which were ascribed to the existence of carbonyl (C=O) and unsaturated (C=C) functional groups at various UV wavelengths. Both seed oils demonstrated noteworthy DPPH radical scavenging activity when compared with the standard (Ascorbic Acid) and strong antimicrobial activity against all tested microbes. According to these results, the oils from C. paradisi and C. lemon seeds have substantial antimicrobial and antioxidant qualities, which supports their possible application in the creation of natural cosmeceutical products that are safe, economical, and environmentally friendly.