Supervisors info:
Μητάκου Σοφία, καθηγήτρια, Φαρμακευτική, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Summary:
The oil deriving from rice bran, namely rice bran oil (RBO), is one of the major by-product of the rice milling industry. RBO represents a rich source of ω-6 FFA and bioactive phytochemicals with pharmaceutical and cosmetic interest such as γ-oryzanol (γOR). γ-Oryzanol is of particular significance because it is abundant in RBO compared to other vegetable oils. Although RBO is considered to be one the healthiest oils in the world, it does not reach its full production potential. RBO is more expensive than other vegetable oils due to its complex refining process. However, the correct management of the wastes in the rice industry can reduce that cost. The exploitation and recycling of the main rice byproducts and residues is an economical opportunity that has benefits for the environment as well. Apart from the commercial part of the matter, the scientific community is interested more and more about the beneficial for the human health activities of RBO’s constituents, and especially γOR.
The aim of the present study is, on the one hand, the determination and quantification of both γOR and PγOR components in rice bran and rice husk and on the other hand, the isolation and structural elucidation of their individual constituents.
Initially, 12 different samples of rice bran and rice husk, of different varieties (Gladio and Ronaldo) obtained throughout the various steps of the milling process, with or without the parboiling technique (PB), were extracted independently twice via ultrasonic extraction using EtOAc. EtOAc was the optimum solvent for the extraction of both γOR and PγOR. The obtained RBO extracts yielded up to 25% (w/w). Additionally, a targeted HPLC-UV method was developed for the separation and quantification of γOR & PγOR in bran/husk (w/w). Taking into accounts the results of the quantification, Gladio parboiled 1st step bran (Gpb1) was chosen for the isolation of γOR’s & PγOR’s individual constituents, which is the second goal of the present study. The fractionation of PγOR and its separation from γOR was succeeded via CPC. The isolation of γOR’s & PγOR’s constituents demands the implementation of more than one chromatographic techniques. γOR’s individual constituents were isolated via semi prep-HPLC whereas PγOR’s individual constituents were isolated via prep- SFC-MS. Their structural elucidation was accomplished by combining LC-HRMSn and NMR (1D& 2D) data.
Keywords:
polar γ-oryzanol, γ-oryzanol, rice bran, rice bran oil, RBO
