• Archives of Pharmacal Research
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• v.14 no.4
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• pp.342-345
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• 1991

Synthesis of series of 3-benzalphthalidyl-amino acids and their corresponding methyl esters, dipeptides and tripeptide methyl esters 2a-7c is decribed. All 3-benzalphthalidynamino acids 2a-g were found to possess a remarkable antimicrobial properties against a number of microorganisms and fungi.

• BMB Reports
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• v.45 no.2
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• pp.114-119
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• 2012

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) is a compound derived from dopamine metabolism and is capable of causing dopaminergic neurodegeneration. Oxidative modification of neurofilament proteins has been implicated in the pathogenesis of neurodegenerative disorders. In this study, oxidative modification of neurofilament-L (NF-L) by salsolinol and the inhibitory effects of histidyl dipeptides on NF-L modification were investigated. When NF-L was incubated with 0.5 mM salsolinol, the aggregation of protein was increased in a time-dependent manner. We also found that the generation of hydroxyl radicals (${\bullet}OH$) was linear with respect to the concentrations of salsolinol as a function of incubation time. NF-L exposure to salsolinol produced losses of glutamate, lysine and proline residues. These results suggest that the aggregation of NF-L by salsolinol may be due to oxidative damage resulting from free radicals. Carnosine, histidyl dipeptide, is involved in many cellular defense processes, including free radical detoxification. Carnosine, and anserine were shown to significantly prevent salsolinol-mediated NF-L aggregation. Both compounds also inhibited the generation of ${\bullet}OH$ induced by salsolinol. The results indicated that carnosine and related compounds may prevent salsolinol-mediated NF-L modification via free radical scavenging.

• Biomolecules & Therapeutics
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• v.16 no.4
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• pp.356-363
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• 2008

A bacterial strain with good antibacterial activities against Staphylococus aureus and Escherichia coli was isolated from a marine sponge Stelleta sp., and it was identified as a Psychrobacter sp. by comparative 16S rDNA sequence analysis. In our search for bioactive secondary metabolites from this psychrophillic and halotolerent bacterium, sixteen cyclic dipeptides (1-16) were isolated and their structures were identified on the basis of NMR analysis. In the test of the compounds for the protective effect against Vibrio vulnificusinduced cytotoxicity in human intestinal epithelial cells, cyclo-(L-Pro-L-Phe) (5) exhibited significant protective effect. Compounds 2, 6, and 11, which contain D-amino acid, were first isolated from bacteria.

• Journal of the Korean Chemical Society
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• v.19 no.3
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• pp.169-173
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• 1975

Ten previously unreported dipeptides ontaining aminobenzylphosphonic acid were prepared by carbodiimide method. These are; Glycyl-dl-1-aminobenzylphosphonic acid, alanyl-dl-1-aminobenzylphosphonic acid, L-alanyl-dl-1-aminobenzylphosphonic acid, N-phthalyl-L-phenylalanyl-dl-1-aminobenzylphosphonic acid diethyl ester, N-carbobenzoxyglycyl-dl-1-aminobenzylphosphonic acid diethyl ester, N-carbobenzoxyalanyl-dl-1-aminobenzylphosphonic acid diethyl ester, N-carbobenzoxy-L-alanyl-dl-1-aminobenzylphosphonic acid diethyl ester, glycyl-dl-1-aminobenzylphosphonic acid diethyl ester hydrobromide, alanyl-dl-1-aminobenzylphosphonic acid diethyl ester hydrobromide and L-alanyl-dl-1-aminobenzylphosphonic acid diethyl ester hydrobromide. The first six compounds were characterized, and the last four compounds were obtained in the crude state.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.409-414
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• 2009

Novel binol aldehydes derivatized at 2' hydroxy position with both uryl and acetamide groups (2), and diuryl groups (3) have been synthesized. Both were designed for streospecific binding and chirality conversion of general dipeptides with support of multiple hydrogen bonding donor sites in the receptors. The receptors, 2 and 3, converted the chirality of N-terminal amino acids of peptides such as Ala-Gly, Met-Gly, Leu-Gly and His-Gly with stereoselectivity on D-form over L-form. The stereoselectivity ratios were in the range of 5-11, somewhat higher than those of the binol receptor with mono uryl group (1). The DFT calculation at the B3LYP/6-31G$^*$//MPWB1K/6-31G$^*$ level revealed that 3-D-Ala-Gly was 2.2 kcal/mol more stable than 3-L-Ala-Gly. The considerable steric hindrance between the methyl group of the alanine and the imine CH moiety of the receptor seems to be the main contributing factor for the thermodynamic preference.

• Natural Product Sciences
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• v.29 no.2
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• pp.59-66
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• 2023

The anti-melanogenic activity of 259 actinomycete strains was tested, and based on the results for the inhibition of mushroom tyrosinase activity and the reduction in melanin content, Micromonospora sp. JCS1 and JCS7 were selected as the strains with the highest anti-melanogenic potential. The activity-guided fractionation of extracts from JCS1 and JCS7 led to the isolation of the dipeptides cyclo(ʟ-Phenyl alanine (Phe)-ʟ-Proline (Pro)) (1) and cyclo(ʟ-Tryptophan (Trp)-ʟ-Proline (Pro)) (2). These two compounds were tested for their inhibition of mushroom tyrosinase by monitoring ʟ-DOPA levels and melanin production. Cyclo(ʟ-Phe-ʟ-Pro) (1) and cyclo(ʟ-Trp-ʟ-Pro) (2) were thus confirmed to have the potential for use in functional whitening cosmetics containing actinomycete-derived secondary metabolites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.229-242
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• 2018

The effects of orally administered fermented porcine placenta (FPP) and its major dipeptides, L-Leucyl-Glycine (Leu-Gly) and Glycyl-L-Leucine (Gly-Leu), on UVB-induced wrinkle formation of the skin in hairless mice was studied. Treatment with FPP, Leu-Gly or Gly-Leu increased type I procollagen synthesis and decreased MMP-1 (matrix metalloproteinase-1) in human dermal fibroblast cells (HDF-N). Hairless mice were also exposed UVB irradiation three times a week and fermented porcine placenta extract (FPP), Leu-Gly and Gly-Leu was administered once a day for eight weeks. Daily intake of FPP, Leu-Gly and Gly-Leu for eight weeks decreased wrinkles, erythema and thickness of the skin and increased skin hydration and synthesis of collagen relative to a UVB-control. Moreover, FPP, Leu-Gly or Gly-Leu intake decreased the expression of MMP-3 and MMP-13 mRNA levels and inhibited activation of MMP-2 and MMP-9 induced by UVB irradiation in hairless mice skin. These results suggest that major dipeptides of the placenta, Leu-Gly and Gly-Leu have the potential for use as a functional food ingredient with anti-wrinkling properties.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.15-15
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• 1996

In order to investigate the conformational preferences to elicit the tastes, conformational free energy calculations using the empirical potential ECEPP/3 and the hydration shell model were carried out on the L-aspartyl dipeptide methyl esters, L-$\^$+/HAsp$\^$-/-D-Xaa-OMe, in the unhydrated state, where Xaa includes sweet (Ala, Abu, Ser, Thr, Val, and lle), bitter (Phe, Trp, and Leu), and tasteless (Tyr and Met) residues. (omitted)

• Archives of Pharmacal Research
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• v.15 no.3
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• pp.204-207
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• 1992

Glycylglycine, alanylalanine and alanylglycine were synthesized, their free carboxylic and amino groups were converted to methyl esters of N-acetylglycyglycine, N-acetylalanylglycine and N-acetylalanylalanine. The synthesized compounds were evaluated for antiepileptic activity, plasmaprotein binding, $TD_{50}$ and potentiating effect of phenobarbitone sodium.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.119-119
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• 1997

Valacyclovir is a L-valyl ester prodrug of acyclovir which is a highly effective and selective antiviral agent in the treatment of herpes virus diseases. Valacyclovir is rapidly and almost completely converted to acyclovir and increases the oral bioavailability of acyclovir three to five fold. However, the intestinal absorption mechanism of valacyclovir is not clear. If the improved absorption mechanism of valacyclovir is fully understood, it will provide a rationale of designing the amino acid ester prodrugs of polar drugs containing hydroxyl group. The main objective of our present study is to characterize the membrane transport mechanism of valacyclovir. Methods : Intestinal absorption of valacyclovir was investigated by using in-situ rat perfusion study and its wall permeability was estimated by modified boundary layer model. The membrane transport mechanism was also investigated through the uptake study in Caco-2 cells and in CHO-hPepTl cells. Results : In the rat perfusion study, the wall permeability of valacyclovir was ten times higher than acyclovir and showed concentration dependency, Valacyclovir also demonstrated a D,L stereo-selectivity with L-isomer having an approximately five-fold higher permeability than D-isomer. Mixed dipeptides and cephalexin, which are transported by dipeptide carriers, strongly competed with valacyclovir for the intestinal absorption, while L-valine did not show any competition with valacyclovir. This indicated that the intestinal absorption of valacyclovir could be dipeptide carrier-mediated. In addition, the competitive uptake study in Caco-2 cells presented that dipeptides reduced the valacyclovir uptake but valine did not. Also, in IC$\sub$50/ study, valacyclovir showed strong inhibition on the $^3$H-gly-sar uptake in CHO-hPepTl cells over-expressing a human intestinal peptide transporter. Taken together, the result from our present study indicated that valacyclovir utilized the peptide transporter for the intestinal absorption.