A novel conversion of sesamolin to sesaminol by acidic cation exchange resin

Abstract

Sesame (Sesamum indicum L.) seed and its oil contain abundant lignans, including sesamin, sesamolin, sesamol, sesaminol, and their glycosides. In the present study, a novel reaction pathway, using an anhydrous solvent system, cation exchange resin catalyst, and HPLC for detection, was employed for the conversion of sesamolin into sesaminol. Under optimal conditions of 5 mL toluene, 90°C, initial sesamolin concentration of 6 mM, and catalyst dosage of 16.66 g/mmol of sesamolin, a 75.0% yield of sesaminol was achieved. The reaction mechanism was inferred to be that of a Friedel–Crafts reaction, with the catalyst showing remarkable catalytic activity and producing only slightly decreased yield after reuse in five subsequent batches. Owing to excellent reusability, low cost, and ready availability, this catalyst provides a very satisfactory option for converting sesamolin to sesaminol.

Practical applications: Sesaminol is a potential natural antioxidant for use as a food additive and in medicinal applications, but it is a naturally occurring trace compound, and could be transformed from sesamolin under proper, specific conditions. The cation exchange resin 732 provides a satisfactory option for catalyzing the conversion of sesamolin into sesaminol. This suggests encouraging prospects for practical or industrial applications utilizing its notable catalytic performance, reusability, low cost, and easy availability.