Characterization of Gamma-Irradiated Rosmarinus officinalis L. (Rosemary)

Objectives: Rosmarinus officinalis L., a member of the family Lamiaceae, is regarded as the spice with the highest antioxidant activity. Materials and Methods: In this study, the transmission electron microscopy, X-ray diffraction, and fourier transform infrared spectroscopy (FTIR) physicochemical characteristics of the nanostructure of gamma-irradiated rosemary were investigated. Results: The particle size distribution of the gamma-irradiated rosemary prepared under irradiation at 30 kGy in a Cobalt-60 irradiator exhibited a very narrow size distribution with average size of 70 nm. The results showed that irradiated (30 kGy) and crude rosemary had similar patterns of FTIR spectra, typical of phenol compound, without any notable changes in the key bands and functional groups status. Rosemary irradiated with 50 kGy and 10 kGy showed the highest and lowest crystallinity, respectively. Rosemary crystallinity of irradiated samples was lower compared with the nonirradiated sample. Conclusion: Therefore, 30 kGy can be optimum for the synthesis of nanoparticles, average size of 70 nm, with low crystallinity and without any notable change in key bands compared to nonirradiated samples.