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The effects of several flavonoids and other known antioxidants on the thermal autoxidation of refined, bleached and deodorized (RBD)‐palm oil were studied. The lipid peroxidation was indexed by measuring the malonyldialdehyde (MDA) production using the 2‐thiobarbituric acid (TBA) test. The antioxidative action decreased in the order of morin > kaempferol > myricetin > quercetin > vitamin A > α‐tocopherol > apigenin > (+)‐catechin > chrysin > datiscetin > luteolin > naringin > taxifolin > rutin > butylated hydroxytoluene (BHT) > naringenin.The flavonoid aglycones were more potent in their antiperoxidative action than their corresponding glycosides. Structure‐activity revealed that the flavonoid molecule with polyhydroxylated substitutions on rings A and B, a 2–3 double bond, a free 3‐hydroxyl substitution and a 4‐keto moiety, would confer potent antiperoxidative properties upon the compound. The flavonols, namely morin, myricetin, kaempferol and quercetin, would be suitable potential antioxidants for use in the stabilization of RBD‐palm oil and its fractions against thermal autoxidation. The structural activity of the flavonoids on the RBD‐palm oil was similar to those observed for these compounds in animal tissue or enzyme systems.

SummaryBackground. The increasing use of long-lasting nail aesthetic products has led to a growing number of cases of allergic contact dermatitis (ACD) caused by (meth)acrylates in recent years. Objectives. To provide information on ACD caused by (meth)acrylates related to nail cosmetic products. Methods. We retrospectively reviewed files of patients with ACD caused by (meth)acrylates related to nail cosmetic products, who were patch tested between January 2011 and December 2015 in 13 departments of dermatology in Portugal. Results. Two-hundred and thirty cases of ACD caused by (meth)acrylates (55 technicians, 56 consumers, and 119 with mixed exposure) had been documented, mostly as chronic hand eczema (93%). The most common sensitizers were: 2-hydroxyethyl methacrylate (HEMA), which was positive in 90% of the tested patients, 2-hydroxypropyl methacrylate (HPMA), which was positive in 64.1%, and ethyleneglycol dimethacrylate, which was positive in 54.5%. Conclusion. HEMA and HPMA were the most frequent positive allergens. HEMA, which identified 90% of cases, can be considered to be a good screening allergen. The high number of cases of ACD caused by (meth)acrylates in nail cosmetic products certainly warrants better preventive measures at the occupational level, and specific regulation in the field of consumer safety.

Treatment of the thiosemicarbazone ligands 4‐MeC6H4C(Me)=NN(H)C(=S)NHMe (a), 4‐MeC6H4C(Me)=NN(H)C(=S)NHEt (b), and 4‐MeC6H4C(Me)=NN(H)C(=S)NHPh (c) with K2[PdCl4] produced the tetranuclear palladium(II) compounds [Pd{4‐MeC6H3C(Me)=NNC(=S)NHMe}]4 (1a), [Pd{4‐MeC6H3C(Me)=NNC(=S)NHEt}]4 (1b), and [Pd{4‐MeC6H3C(Me)=NNC(=S)NHPh}]4 (1c) with deprotonation of the NH group. Treatment of thiosemicarbazones 4‐MeOC6H4C(H)=NN(Me)C(=S)NH2 (d) and 3‐MeOC6H4C(H)=NN(Me)C(=S)NH2 (e) with K2[PdCl4] gave the mononuclear palladium(II) compounds [Pd{4‐MeOC6H3C(H)=NN(Me)C(=S)NH2}(Cl)] (1d) and [Pd{3‐MeOC6H3C(H)=NN(Me)C(=S)NH2}(Cl)] (1e). Treatment of the Schiff base 4‐MeOC6H4C(H)=N[2‐(SMe)C6H4] (f) with Li2[PdCl4] afforded [Pd{4‐MeOC6H3C(H)=N[2‐(SMe)C6H4]}(Cl)] (1f). All the ligands are terdentate through the [C,N,S] atoms and the Pd−S bond formed is sufficiently strong to tolerate treatment with nucleophiles without bond cleavage. Treatment of 1a, 1b, and 1c with triphenylphosphane gave the mononuclear species 2a, 2b, and 2c, which upon treatment with hydrochloric acid resulted in the 1:1 electrolytes 3a, 3b, and 3c, with NH and C=S groups. Coordination of PPh3 to Pd in 1f was achieved by treatment of the compound with sodium perchlorate, followed by the nucleophile in a 1:1 molar ratio, to yield 2f. The crystal structures of compounds 2a and 1f are described.

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