• Journal of Pharmaceutical Investigation
• /
• v.40 no.4
• /
• pp.251-254
• /
• 2010

The formation of acylated peptide impurities in poly(lactide-co-glycolide) (PLGA) formulations is one of the major challenges to the development of successful sustained-release product. Octreotide, synthetic analogue of somatostatin, has been identified to be acylated in PLGA microsphere formulations. The purpose of this study was to investigate the pH effect on the formation of acylated octreotides by PLGA. In the incubation with PLGA in 0.1 M phosphate buffer at pH 7.4, approximately 98% of octreotide adsorbed to PLGA through 14 days and 66.3% of acylated octreotides were produced after 42 days, whereas the interaction of octreotide with PLGA was significantly inhibited in the incubation at pH 4, in which the acylated octreotides were observed to be 9.2% after 42 days. In the interaction study at pH 4.1-7.4, the production of acylated octreotides was demonstrated to be dependent on environmental pH. Below pH 5.0, the acylation of octreotide was significantly inhibited. This study indicates that the pH is the major factor for the formation of acylated octreotide in PLGA formulations.

• Preventive Nutrition and Food Science
• /
• v.2 no.3
• /
• pp.191-196
• /
• 1997

The antioxidative activity of seven different acylated anthocyanin pigments isolated from grape, sweet potato, eggplant and red cabbage was evaluated bvy using linoleic acid autoxidation and rat liver microsomal systems. The acylated anthocyanins were isolated and purified by Amberlite SAD-7, ODS and Sephadex LH-20 column omatography, and preparative HPLC. Most of acylated anthocyanisns exhibited antioxidative activity as strong as $\alpha$-tocoperol, and especially peonidin3-O--(6-O-trans-caffeyl)-2-O-(6-O-trans-feuloylglucopyranosyl)-$\beta$-D-glucopyranosyl-5-O-$\beta$-D-glucopyranoside from purple sweet potato showed the strongest activity, comparable to BHA (not significant, p<0.05) in the linoleic acid system. Meanwhile, two acylated anthocyanins from the pericarps of grape and eggplant inhibited considerably the MDA formation from rat liver microsomal lipid peroxidation induced by FeSO$_4$/$H_2O$$_2$. In particular, malvidin 3-O-(6-O-p-coumaroyl)-$\beta$-D-glucopyranosde from grape pericarps showed the strongest antioxidant activity, comparable to $\alpha$-tocopherol (not significant, p<0.05). These results suggest that the acylated anthocyanins from fruits and vegetables can be used as potential dietary ntioxidants and natural colorants.

• Archives of Pharmacal Research
• /
• v.14 no.1
• /
• pp.52-54
• /
• 1991

A new acylated monoterpene glucoside, galloylpaeoniflorin, was isolated from Paeony root. The structure was determined by chemical and spectroscopic methods.

• The Korean Journal of Food And Nutrition
• /
• v.2 no.1
• /
• pp.18-26
• /
• 1989

The objective of this study was to improved the limited functional characteristics of mungbean whole globulin. The mungbean whole globulin was acylated with succinic and acetic anhydride, and the functional properties of acylated protein were investigated, The results obtained ware as follows. 1. The UV-absorption spectra of acylated whole globulins with that of the succinylated 74% whole globulin as large blue shift of the absorption maximum and minimum wavelength from 275 nm to 269 nm, respectively. 2. The mobility of acylated whole globulin were increased on PAGE pattern, and degree of mobility was particularly remarkable in case of succinylation, 3. The water absorption capacity of whole globulin was increased by acylation. The most increased rate of whole globulin was 174,02% from succinylated 74%. The oil absorption capacity of whole globulin was increased by acylation The most increased rate of whole globulin was 165.41% from acetylated 81.77%. 4. The bulk density of whole globulin was decreased by acylation. and the greater the extent of acylation, the smaller the bulk density. 5. The foaming capacity and stability of whole globulin was increased by acylation, and remarkably high in 74% succinylated whole globulin. In contrast, however, the foaming capacity and stability of native and acylated whole globulin were decreased by heat treatment.

• Natural Product Sciences
• /
• v.9 no.4
• /
• pp.241-244
• /
• 2003

A new (2) and a known (1) acylated taurine derivatives were isolated from MeOH extract of the starfish Certonardoa semiregularis. Another new acylated taurine derivative (3) was isolated from the MeOH extract of the sponge Erylus nobilis. The structures were determined on the basis of spectral analysis.

• Archives of Pharmacal Research
• /
• v.13 no.2
• /
• pp.207-210
• /
• 1990

The position of interglycosidic linkages of two acylated flavonol glucorhamnosides from Ginkgo biloba leaves was unambiguously determined as 1 $\longrightarrow$ 2 linkages rather than 1 $\longrightarrow$ 4 ones on the basis of spectroscopic and chemical evidence.

• Korean Journal of Pharmacognosy
• /
• v.30 no.3
• /
• pp.290-294
• /
• 1999

From the legumes of Albizzia julibrissin Durazzini (Leguminosae), a mixture of long-chain alcohols, ${\alpha}-spinasterol$, a mixture of acylated sterol glycosides and ${\alpha}-spinasteryl$ $3-O-{\beta}-D-glucoside$ were isolated. Two mixtures of long-chain alcohols and acylated sterol glycosides were characterized as 1-hexacosanol (major) and 1-tetracosanol, and $3-O-[6'-O-palmitoyl-{\beta}-D-glucosyl]-{\alpha}-spinasterol$ (major) and its 6'-O-stearoyl ester. All compounds were identified on the basis of spectral data and chemical reactions.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.3
• /
• pp.703-706
• /
• 2009

• Applied Biological Chemistry
• /
• v.33 no.1
• /
• pp.52-61
• /
• 1990

Fish protein was acylated with acetic anhydride(AA), succinic anhydride(SA) and maleic anhydride(MA) in order to improve the functional properties of the protein. The surface hydrophobicity and functional properties of protein were measured to study the relationship between them. It was found that the extented acylation of nucleophilic groups such as amino and sulfhydryl groups of the amino acid residues of fish protein was higher than other groups when acylated with AA, and the degree of acylation was 89.5 % for amino groups and 72.2 % for sulfhydryl groups. The surface hydrophobicity of fish protein was decreased by succinylation and maleylation, whereas acetylation caused tittle change. The acylated fish protein concentrate(FPC) showed higher surface hydrophobicity than the acylated fish myofibrilla protein(FMP). Acylation with AA, SA and MA of fish protein resulted in a significant increase in protein solubility, emulsifier properties, foaming properties, water adsorption capacity and oil adsorption capacity. These properties of acylated FMP were more improved than those of acylated FPC. Decrease in protein hydrophobicity was highly correlated with increase in protein solubility, and emulsifier properties and foaming properties were largely dependent on the solubility as well as surface hydrophobicity. The water adsorption capacity of the protein was significantly affected by solubility. Surface hydrophobicity had greater influence on oil adsorption capacity, whereas it had tittle effect on water adsorption capacity.

• Journal of Pharmaceutical Investigation
• /
• v.41 no.2
• /
• pp.91-94
• /
• 2011

The purpose of this study was to investigate the effect of peptide charge on the interaction between peptide and poly(D,L-lactide-co-glycolide) (PLGA) for evaluating mechanism of acylated peptide formation in PLGA matrix. As a model peptide, octreotide, a synthetic somatostatin analogue and active ingredient of commercial PLGA product, was used. The disulfide group of octreotide was reduced with dithiothreitol and the sulfhydryl groups were modified with N-${\beta}$-maleimidopropionic acid (BMPA) to neutralize octreotide with positive charge in physiological conditions. The BMPA-conjugated octreotide was identified by measuring the molecular mass with liquid chromatography-mass spectrometry. In the interaction study with PLGA, native octreotide showed initial adsorption to PLGA and substantial production of acylated peptides (56% of overall peptide), whereas BMPA-conjugated octreotide showed minimal adsorption to PLGA and no acylation products for 42 days. Consequently, the neutralization of octreotide completely inhibited the peptide acylation by preventing interaction of peptide with PLGA. In conclusion, this study demonstrates that the initial polymer interaction of peptide is important step for peptide acylation in PLGA matrix and suggests the modulation of peptide charge as strategy for inhibiting the formation of acylated peptide impurities.