Anikó M. Sólyom

Studies on the stability of turmeric constituents

In order to investigate the stability of curcuminoids in physiological media, two samples with different composition of curcumin (CUR I), mono-demethoxycurcumin (CUR II) and bis-demethoxycurcumin (CUR III) were incubated in phosphate buffer and cell culture medium without or with fetal calf serum. The curcuminoids decomposed very rapidly (more than 90% within 12 h) when serum was omitted, but were more stable in the presence of serum. The stability differed between the curcuminoids: CUR I was the least, and CUR III was the most stable curcuminoid. Several degradation products of CUR I were detected, most of which were not yet identified; ferulic acid and vanillin were disclosed as minor products.

1,4-Disubstituted anthracene antitumor agents

Three different types of 1,4-disubstituted anthracenes were synthesized, and their cytotoxicity in a panel of tumor cells was compared with that of the corresponding 9,10-disubstituted anthracenes. The panel contained human myeloma, melanoma, colon, and lung cancer cells and sensitive and multidrug-resistant murine L1210 leukemia cells. These compounds had [[(dimethylamino)ethyl]amino]methyl, N-[(dimethylamino)ethyl]carbamoyl, and carboxaldehyde (4,5-dihydro-1H-imidazol-2-yl)hydrazone side chains. The 1,4-diamide was more potent across the tumor panel than the corresponding 9,10-isomer, but the 1,4-diamine and the 1,4-hydrazone were less potent than their 9,10-isomers. Although the 1,4-hydrazone was active against P388 leukemia in mice, it was inactive against L1210 leukemia. Within each pair of compounds, the one with greater average potency against tumor cells gave a greater increase in the transition melt temperature of DNA.

Isolation, Identification, and Quantification of Potential Defensive Compounds in the Viceroy Butterfly and its Larval Host-Plant, Carolina Willow

The viceroy–monarch and viceroy–queen butterfly associations are classic examples of mimicry. These relationships were originally classified as Batesian, or parasitic, but were later reclassified as Müllerian, or mutalistic, based on predator bioassays. The Müllerian reclassification implies that viceroy is unpalatable because it too is chemically defended like the queen and the monarch. However, unlike the queen and the monarch, the viceroy defensive chemistry has remained uncharacterized. We demonstrate that the viceroy butterfly (Limenitis archippus, Nymphalidae) not only sequesters nonvolatile defensive compounds from its larval host–plant, the Carolina willow (Salix caroliniana, Salicaceae), but also secretes volatile defensive compounds when disturbed. We developed liquid chromatography–mass spectrometry–mass spectrometry methods to identify a set of phenolic glycosides shared between the adult viceroy butterfly and the Carolina willow, and solid phase microextraction and gas chromatography–mass spectrometry methods to identify volatile phenolic compounds released from stressed viceroy butterflies. In both approaches, all structures were characterized based on their mass spectral fragmentation patterns and confirmed with authentic standards. The phenolics we found are known to deter predator attack in other prey systems, including other willow-feeding insect species. Because these compounds have a generalized defensive function at the concentrations we described, our results are consistent with the Müllerian reclassification put forth by other researchers based on bioassay results. It seems that the viceroy butterfly possesses chemical defenses different from its monarch and queen butterfly counterparts (phenolic glycosides vs. cardiac glycosides, respectively), an unusual phenomenon in mimicry warranting future study.