Synthesis, characterization, and optimization of antimicrobial biolubricant derived from Ocimum lamiifolium and lactic acid

Optimal extraction parameters were determined, yielding 12.4 % oil at 4.5 h, with a particle size of 1.375 mm and a solute-to-solvent ratio of 0.28 w/v. The extracted oil exhibited high yield (15 % moisture, 0.92 g/mL specific gravity), a volatile lubricant component (3 %), a pH of 4.2-5.91, low ash (11.5 %), high saponification value (19.7 g KOH/g) and moderate acid number (8.9 mg KOH/g), iodine value of 35.3 g/L, low viscosity (0.1160 Pa s), and high diffusion capacity (95 %). Chemical analysis using UV-Vis spectrophotometry was employed to identify the constituents present in the extract, while FTIR spectra indicated the presence of alcoholic and phenolic components, suggesting interactions with lactic acid. Through GC/MS analysis, a total of 32 phytochemicals were identified, with seven significant ones: Eugenol (Phenol), Isocaryophyllene, Elemicin (benzene), Hexadecanoic acid with methyl ester, Octadecanoic acid with methyl ester, Neophytadiene and Squalene. Evaluation against <i>E. coli, B. subtilis, S. typhimurium,</i> and <i>S. aureus</i> revealed the <i>O. lamiifolium</i> extract and biolubricants most active against <i>S. aureus</i> and <i>E. coli,</i> suggesting potential for superior antibacterial lubricants with this plant extract and lactic acid.