Ichiro Yokoe

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Berberine iodide (IK-1) and acetoneberberine (IK-2) showed higher cytotoxicity against five human oral squamous cell carcinoma (HSC-2, HSC-3, HSC-4, NA, CA9-22) and one human promyelocytic leukemia (HL-60) cell lines, than against normal human oral tissue-derived cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF), producing(More)
o-Methoxyphenols such as eugenol and isoeugenol exhibit anti-oxidant and anti-inflammatory activities, but at higher concentrations act as oxidants and potent allergens. We recently demonstrated the eugenol dimer bis-eugenol to be an efficient inhibitor of lipopolysaccharide (LPS)-induced inflammatory cytokine expression in macrophages without cytotoxicity.(More)
To investigate the possible link between radicals and cytotoxicity of eugenol-related compounds, dimer compounds were synthesized from eugenol (4-allyl-2-methoxyphenol) or isoeugenol (4-propenyl-2-methoxyphenol): bis-eugenol (3,3'-dimethoxy-5,5'-di-2-propenyl-1,1'-biphenyl-2,2'-diol); dehydrodiisoeugenol(More)
A total of 6 newly-synthesized styrylchromones (SC-1 approximately SC-6) were compared for their cytotoxic activity against three normal oral human cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF) and four human tumor cell lines (squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG, promyelocytic(More)
The ability of nine synthetic eugenol-related compounds to scavenge O2- (generated by the hypoxanthine-xanthine oxidase reaction) was compared with their radical generation and cytotoxic activity. ESR spectroscopy showed that eugenol (4-allyl-2-methoxyphenol), 2-allyl-4-methoxyphenol, 2-allyl-4-t-butylphenol and 2,4-dimethoxyphenol efficiently scavenged O2-(More)
Butylated hydroxyanisole (BHA; a mixture of 2- and 3-BHA) is widely used as a potent antioxidant, but is reported to have adverse effects, such as carcinogenesis and pro-inflammatory activity, possibly due to the pro-oxidant property of this compound. 2-Methoxyphenol dimers derived from ferulic acid were recently demonstrated to inhibit the expression of(More)
The dimers bis-EUG, bis-MMP, bis-BHA, bis-BMP and bis-DBP were synthesized from the monomers 4-allyl-2-methoxyphenol (EUG), 2-methoxy-4-methylphenol (MMP), 2-t-butyl-4-methoxyphenol (BHA), 2-t-butyl-4-methylphenol (BMP) and 2,4-di-t-butylphenol (DBP), respectively. The stoichiometric factors (n; number of free radicals trapped by one mole of phenolic(More)
The radical intensity of BHA (4-Hydroxy-3-t-butylanisole) and its dimer (3,3'-Di-t-butyl-5,5'-dimethoxy-1,1'-biphenyl-2,2'-diol, Bis-BHA) were compared with their cytotoxic activity. ESR spectroscopy showed that BHA produced characteristic five peaks of radicals under alkaline conditions (pH > 9.5). At higher pH, BHA radical rapidly disappeared, and(More)
To clarify the radical-scavenging activity of butylated hydroxytoluene (BHT), a food additive, stoichiometric factors (n) and inhibition rate constants (kinh) were determined for 2,6-di-tert-butyl-4-methylphenol (BHT) and its metabolites 2,6-di-tert-butyl-p-benzoquinone (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHA-CHO) and(More)
UNLABELLED Selective cyclooxygenase (COX)-2 inhibitors have attracted much attention in relation to the design of non-steroidal anti-inflammatory agents (NSAIDs). The relationship between experimentally derived data on the antioxidant capacity, cytotoxicity and COX-2 inhibition for a range of 2-methoxyphenols and their calculated descriptors was(More)