Gamma irradiation-assisted degradation of rosmarinic acid and evaluation of structures and anti-adipogenic properties.

Radiation is a promising technique for improving the safety and shelf-life of processed foods. In the present investigation, the degradation mechanism and bioactivity improvement of rosmarinic acid (RA) were studied in response to various gamma irradiation doses (10, 20, and 50 kGy). RA exposed to gamma irradiation at 50 kGy was completely degraded and showed an increased inhibitory effect against 3 T3-L1 preadipocyte compare to the parent compound. Structures of the newly generated compounds 2-4 from irradiated RA at 50 kGy were elucidated based on spectroscopic methods, including 1 H nuclear magnetic resonance (NMR) and mass spectrometry (MS). Interestingly, compounds 2 and 5 exhibited significantly enhanced anti-adipogenic properties in 3 T3-L1 cells compared to the original compound. These results provide evidence that structural changes in RA induced by gamma irradiation might enhance biological efficacy.