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The value of amino acids and vegetable oil derivatives as raw materials for the preparation of surfactants was recognized as soon as they were discovered early in the last century. Amino acid-based surfactants, which have an amino acid residue as a hydrophilic moiety, are reviewed with respect to their synthesis, properties and some applications. The review covers three main categories of amino acid-based surfactants: N a -acyl, N-alkyl amide and O-alkyl ester derivatives among the linear or single chain amino acid-based surfactants; N a , N w -bis(N a -acylarginine)a,w-alkylendiamides, which are gemini amino acid-based surfactants; and 1-monoacyl-rac-glycero-3-O-(N a -acetyl-L-amino acid) and 1,2-diacyl-rac-glycero-3-O-(N a -acetyl-L-amino acid), both amino acid-based surfactants with glycerolipid-like structures.Scheme 1 Structures of amino acid-based surfactants: (1) Linear or single chain, (2) Dimeric or Gemini and (3) Glycerolipid-like structures. The amino acid constitutes the polar head of the surfactant. The hydrocarbon alkyl chain constitutes the hydrophobic moiety.2 3 3 G r e e n C h e m . , 2 0 0 4 , 6 , 2 3 3 -2 4 0

trans-3,5,4'-Trihydroxystilbene (trans-resveratrol) is a phytochemical present in peanuts, grapes and wine with beneficial effects such as protection against cardiovascular disease and cancer prevention. The purpose of this study was to evaluate whether high doses of trans-resveratrol have harmful effects on Sprague-Dawley rats. trans-Resveratrol was administered orally to male rats for 28 d at a dose of 20 mg/(kg x d), 1000 times the amount consumed by a 70-kg person taking 1.4 g of trans-resveratrol/d. Body weight, and food and water consumption did not differ between rats treated with trans-resveratrol and the control group. Hematologic and biochemical variables were not affected by the treatment. Histopathologic examination of the organs obtained at autopsy did not reveal any alterations. These results support the view that repeated consumption of trans-resveratrol at 20 mg/(kg x d) does not adversely affect the variables tested in rats.

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Three different sets of cationic surfactants from lysine have been synthesized. The first group consists of three monocatenary surfactants with one lysine as the cationic polar head with one cationic charge. The second consists of three monocatenary surfactants with two amino acids as cationic polar head with two positive charges. Finally, four gemini surfactants were synthesized in which the spacer chain and the number and type of cationic charges have been regulated. The micellization process, antimicrobial activity, and hemolytic activity were evaluated. The critical micelle concentration was dependent only on the hydrophobic character of the molecules. Nevertheless, the antimicrobial and hemolytic activities were related to the structure of the compounds as well as the type of cationic charges. The most active surfactants against the bacteria were those with a cationic charge on the trimethylated amino group, whereas all of these surfactants showed low hemolytic character.