Dry sesamol emulsions were synthesized from several combinations of saccharose with hydroxypropylmethylcellulose (HPMC) or sodium caseinate (SC) using spray-drying techniques at 1201 to 1801C, or freeze-drying. On the basis of physical characteristics such as droplet size distribution, residual moisture, and microscopic structure, the best material was obtained when spray-drying was applied at either 1501 or 1801C with SC or HPMC as excipients, respectively. The extent to which the antioxidant properties of free sesamol towards a set of free radicals (galvinoxyl, diphenylpicrylhydrazyl, superoxide, and hydroxyl) were altered in the starting and reconstituted liquid emulsions submitted to normal storage or pre-exposed to a flux hydroxyl radicals was investigated. Emulsions were further evaluated for their antioxidant properties in cultured 3T3 murine fibroblasts and in an ex vivo model of ultraviolet irradiated rat skin. It was found that, in the material having the best physical properties, encapsulation was decisive in: (1) improving the overall antioxidant behavior of reconstituted versus starting liquid emulsions: (2) sparing sesamol consumption due to free radical attack; and (3) significantly protecting cells and skin against free radical-or irradiation-induced enzymatic release and/or lipid peroxidation. Demonstrating a high activity at high dilutions where interactions of excipient become negligible, the new emulsions could be of great interest in sesamol-based pharmacology or topical applications. Drug Dev Res 69: 251-266, 2008.

Hydrosoluble sesame oil fatty acid transesters having enhanced antioxidant activities were synthesized in a two-step process. The key step involved the biocatalyzed (lipase from Candida antarctica) acylation of sesame oil methanolic ester with either vanillyl (VNA) or piperonyl benzylic alcohols, or 5-hydroxymethyl resorcinol (5-HMR). These substrates were selected to introduce phenolic or sesamol structurally related frameworks. The VNA and 5-HMR-derived transesters were obtained with 20-40% yields and retained the starting proportions of sesame oil linoleic, oleic, and saturated acids, these fatty acids also being the only constituents of the nonesterified fraction. The VNA-derived transester showed the best antioxidant capacity in standard assays and was processed as the unique lipid phase of spray-dried emulsions containing a high level of linoleic acid phenolic ester. These emulsions provided a high degree of protection to UV-irradiated fibroblasts, through the potential synergy between VNA antioxidant action and replenishment of damaged membranes by unsaturated fatty acids.

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