Rapid and Direct Synthesis of Fatty Acid Methyl Esters and Macro-Micro Elemental Analysis of Iris barnumiae Foster & Baker

Abstract

A simplified and rapid protocol to direct synthesis of fatty acid methyl esters (FAMEs) and elemental contents from Iris barnumiae. The production of fatty acid methyl ester from Iris barnumiae (roots) through trans-esterification by using hydrochloric acid/methanol was conducted by microwave-assisted irradiation and compared with conventional heating (reflux). These results show that microwave irradiation is a fast and efficient method for FAME synthesis. Fatty acids or their derivatives FAMEs were identified and quantified by using GC–MS/MS. The classical method highlights prominent compounds such as methyl tetradecanoate (28.66%), palmitic acid methyl ester (18.96%), 9,11-octadecadienoic acid methyl ester (7.38%), and 9-octadecenoic acid methyl ester (14.27%). In contrast, the microwave method demonstrates an enriched profile, with notable components such as methyl tetradecanoate (24.27%), myristic acid (23.59%), palmitic acid methyl ester (21.39%), and n-hexadecanoic acid (11.28%). Unique compounds like 3-(3,4-dimethoxyphenyl)-8-methoxychromen-2-one (8.04%) were detected exclusively in the microwave-assisted extraction. The elemental composition of Iris barnumiae highlights its significant medicinal and nutritional potential, with essential macro- and microelements distributed across its flowers, leaves, and roots. ICP-MS analysis revealed high concentrations of potassium in flowers (30,200 mg/kg), and calcium and magnesium in leaves (28,300 and 3230 mg/kg respectively). In contrast, some toxic elements were found in low concentration. For example, cadmium (Cd) was detected at 0.349 ppm in flowers and 0.347 ppm in leaves. In addition, arsenic (As) and lead (Pb), known for their toxic effects, were present in low concentrations, suggesting that the plant is generally safe.