methyl-caffeate and caffeic-acid-phenethyl-ester

Honeybee propolis and its bioactive component, caffeic acid phenethyl ester (CAPE), are known for a variety of therapeutic potentials. By recruiting a cell-based reporter assay for screening of hypoxia-modulating natural drugs, we identified CAPE as a pro-hypoxia factor. In silico studies were used to probe the capacity of CAPE to interact with potential hypoxia-responsive proteins. CAPE could not dock into hypoxia inducing factor (HIF-1), the master regulator of hypoxia response pathway. On the other hand, it was predicted to bind to factor inhibiting HIF (FIH-1). The active site residue (Asp201) of FIH-1α was involved in hydrogen bond formation with CAPE and its analogue, caffeic acid methyl ester (CAME), especially in the presence of Fe and 2-oxoglutaric acid (OGA). We provide experimental evidence that the low doses of CAPE, that did not cause cytotoxicity or anti-migratory effect, activated HIF-1α and inhibited stress-induced protein aggregation, a common cause of age-related pathologies. Furthermore, by structural homology search, we explored and found candidate compounds that possess stronger FIH-1 binding capacity. These compounds could be promising candidates for modulating therapeutic potential of CAPE, and its recruitment in treatment of protein aggregation-based disorders.

Topics: Caffeic Acids; Cell Hypoxia; Cell Line, Tumor; Cell Movement; Computational Biology; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mixed Function Oxygenases; Molecular Docking Simulation; Phenylethyl Alcohol; Protein Aggregates; Stress, Physiological

Transthyretin (TTR) is a homotetrameric serum protein associated with amyloidoses such as familial amyloid polyneuropathy and senile systemic amyloidosis. The amyloid fibril formation of TTR can be inhibited through stabilization of the TTR tetramer by the binding of small molecules. In this study, we examined the inhibitory potency of caffeic acid phenethyl ester (CAPE) and its derivatives. Thioflavin T assay showed that CAPE suppressed the amyloid fibril formation of TTR. Comparative analysis of the inhibitory potencies revealed that phenethyl ferulate was the most potent among the CAPE derivatives. The binding of phenethyl ferulate and the selected compounds to TTR were confirmed by the 8-anilino-1-naphthalenesulfonic acid displacement and X-ray crystallography. It was also demonstrated that Bio 30, which is a CAPE-rich commercially available New Zealand propolis, inhibited TTR amyloidogenesis and stabilized the TTR tetramer. These results suggested that a propolis may be efficient for preventing TTR amyloidosis.

Topics: Amyloid Neuropathies, Familial; Amyloidosis; Caffeic Acids; Coumaric Acids; Masoprocol; Phenylethyl Alcohol; Prealbumin; Propolis

An efficient procedure for transesterification of methyl caffeate was developed to produce caffeic acid phenethyl ester analogues with Candida antarctica lipase B using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, as a solvent. The system provided 48.8mM 2-cyclohexylethyl caffeate and 46.9 mM 3-cyclohexylpropyl caffeate with conversion yields of 97.6% and 93.8%, respectively. Reusability of the system was investigated, and the yield of 4-phenylbutyl caffeate was increased from 30.4 to 45.7 mM when the transesterification was carried out under reduced pressure to remove a by-product, methanol. Additionally, we showed that both 2-cyclohexylethyl caffeate and 3-cyclohexylpropyl caffeate exhibit strong antiproliferative activities, which are comparable to that of 5-fluorouracil by MTT assay.

Topics: Caffeic Acids; Cell Line, Tumor; Cell Proliferation; Equipment Reuse; Esterification; Fungal Proteins; Humans; Imidazoles; Ionic Liquids; Lipase; Methanol; Phenylethyl Alcohol; Pressure; Sulfonamides

Efficient replication of HIV-1 requires integration of a DNA copy of the viral genome into a chromosome of the host cell. Integration is catalyzed by the viral integrase, and we have previously reported that phenolic moieties in compounds such as flavones, caffeic acid phenethyl ester (CAPE, 2), and curcumin confer inhibitory activity against HIV-1 integrase. We now extend these findings by performing a comprehensive structure-activity relationship using CAPE analogues. Approximately 30 compounds have been prepared as HIV integrase inhibitors based on the structural lead provided by CAPE, which has previously been shown to exhibit an IC50 value of 7 microM in our integration assay. These analogues were designed to examine specific features of the parent CAPE structure which may be important for activity. Among the features examined for their effects on inhibitory potency were ring substitution, side chain length and composition, and phenyl ring conformational orientation. In an assay which measured the combined effect of two sequential steps, dinucleotide cleavage and strand transfer, several analogues have IC50 values for 3'-processing and strand transfer lower than those of CAPE. Inhibition of strand transfer was assayed using both blunt-ended and "precleaved" DNA substrates. Disintegration using an integrase mutant lacking the N-terminal zinc finger and C-terminal DNA-binding domains was also inhibited by these analogues, suggesting that the binding site for these compounds resides in the central catalytic core. Several CAPE analogues were also tested for selective activity against transformed cells. Taken together, these results suggest that the development of novel antiviral agents for the treatment of acquired immune deficiency syndrome can be based upon inhibition of HIV-1 integrase.

Topics: Animals; Antiviral Agents; Apoptosis; Base Sequence; Binding Sites; Caffeic Acids; Cell Line, Transformed; DNA; DNA Nucleotidyltransferases; Enzyme Inhibitors; HIV; Humans; Hydroxylation; Integrases; Magnetic Resonance Spectroscopy; Molecular Conformation; Molecular Sequence Data; Molecular Structure; Phenylethyl Alcohol; Rats; Structure-Activity Relationship; Tumor Cells, Cultured; Zinc Fingers