Camellia Oil Antioxidant Radiation Active Ingredient And Its Mechanism

Camellia oil, oil from seeds of camellia (Camellia oleifera Abel, Theaceae), has been enjoyed for centuries in China and used extensively in the orient for cooking oil, inks, lubricants, cosmetic and medical products. Experimental evidences have shown that camellia oil possess a wide array of therapeutic properties including detoxicating, antiseptic, antimicrobial, antioxidant, anticancer, antithrombotic, and heart and blood vessel disease preventing effects. However, many researches have focused on the physicochemical properties and general composition of camellia oil, especially its fatty acid profiles, whereas little effort is devoted to identify and isolate the minor potential chemopreventive agents present in camellia oil and assess their properties.The objective of this study was to isolate and identify the bioactive compounds from methanol extract of camellia oil (ME) and to characterize the antioxidant acticivities and the protective properties against UV radiation of these compounds. Some of the conclusions are as follows:1. The antioxidant porperties of camellia oil were evaluated by scavenging ? OH produced by Vc-Cu²⁺-H₂O₂-yeast polysaccharides system and the stable DPPH free radical. Results showed that the refined camellia oil is capable to scavenge the·OH free radicals with an IC₅₀ of 0.7165μ1/mL equivalent to that of 5.31 μg/mL quercetin. The crude camellia oil exhibited stronger antioxidant activity than the refined one in the DPPH assay, which indicated different antioxidants present in the oil.2. The crude methanol extract from camellia oil was either extracted by serial benzene, ether, EtOAc and n-BuOH, then isolated using silica gel column chromatography or fractionated using polyamide resin column chromatography. The obtained fractions (designated as SF1-5 and P1-5) as well as ME were evaluated for their antioxidant activities using DPPH assay. Results showed that the content of total phenolics (TPs) of ME, determined by the Folin-Ciocalteu method, was estimated to be 79.5 mg of p-hydroxibenzoic acid equivalent/kg oil, while that of the total flavonoids was 8.98 mg of rutin equivalent/kg oil. ME exhibited pronounced radical scavenging activity against the stable DPPH radical (with antioxidant capacity IC₅₀ value of 52.37 μg/mL), and three subfractions (SF1-3) separated from ME contributed the most significant activity with IC₅₀ of 28.41, 17.42, and 43.17 ug/mL, respectively. The antioxidant capacity of fractions by Polyamide column chromatography wasP2>P1>P4>P5>P3.3. Consistent with the different capacity of scavenging DPPH, the subtractions from ME showed different compositions and contents as detected by TLC, HPLC-DAD-MS, GC-MS. Kamepferol, as well as some phenolic compounds were first identified from camellia oil. Results showed that the presence of phenolic compounds and flavonoids in each extracts may be responsible for its individual antioxidant activity, and the lipophilic phenolic fractions would likely account for a great part of the antioxidant properties of the oil.4. HPLC analysis of the composition of ME was carried out after exposed to Ultraviolet radiation for 0, 20, 40, 60 min. Results showed that the level of the bioactive compounds tended to decrease, which indicated a possible response to the UV expostion. The different changing patterns of certain compounds in ME to the UV treatment reflected other mechanisms of the UV radition protective effects of ME in the oil.