Isolation and structural elucidation of a peptide derived from Edam cheese that inhibits beta-lactoglobulin transport.

A peptide that inhibits beta-lactoglobulin absorption in an in vitro Caco-2 cell model was isolated from Edam cheese. By 1H-NMR and N-terminal amino acid analyses, the active compound was identified as Asp-Lys-Ile-His-Pro-Phe. The sequence of the hexapeptide is the same as the amino acid sequence of residues 47-52 of beta-casein. The hexapeptide shows remarkable inhibition of beta-lactoglobulin transport at a concentration of 10(-7)M. The possibility exists that this peptide can be applied practically to the prevention of milk-sensitive allergy.

New constituents of the leaves of Alpinia flabellata.

Two new compounds were isolated from the leaves of Alpinia flabellata. The structures of these compounds were determined by a combination of NMR techniques and HREIMS as 4-hydroxy-2-(2,4,5-trimethoxyphenyl)-2E-butenal (1) and rel-labd-12-en-15(16)-olid-7-one-8R-spiro-1'-[2S-(2,4,5-trimethoxyphenyl)-3-cyclohexene] (2).

Phenylbutanoid dimers from the leaves of Alpinia flabellata.

Three phenylbutanoid dimers, cis- and trans-1-(2,4,5-trimethoxy-E-styryl)-2-(2,4,5-trimethoxy-Z-styryl)cyclobutane and 1,2-bis(2,4,5-trimethoxy-Z-styryl)- cyclobutane, were isolated from the leaves of Alpinia flabellata Ridley, together with three known compounds (2,4,5-trimethoxybenzaldehyde, 2,4,5-trimethoxycinnamaldehyde and 3,5-dihydroxy-7,4'-dimethoxyflavone). The structures of these compounds were determined by spectroscopic analysis.

Producing a low ovomucoid egg white preparation by precipitation with aqueous ethanol.

A novel method for producing a low ovomucoid egg white preparation is proposed. Egg white powder (0.5 g) was dissolved in a 10-fold weight of distilled water and adjusted to pH 5, and ethanol was added to the solution at a final concentration of 20% (v/v). The mixture was vigorously stirred and centrifuged. The precipitate was washed three times with 20% ethanol (6.25 ml each), with about 65% of egg white proteins occurring in the precipitate. The use of ELISA demonstrated that 70% of ovomucoid was recovered from the supernatant fraction. However, functionally important proteins such as ovalbumin, ovotransferrin, and lysozyme still remained in the precipitate. These results may be due primarily to the much higher solubility of ovomucoid in this aqueous ethanol. Food quality evaluation showed that high whippability and foam stability were retained in the low ovomucoid preparation as in its material egg white. This product would thus be applicable as a new processed food for ovomucoid-sensitive allergic patients.

6-Methylsulfinylhexyl isothiocyanate and its homologues as food-originated compounds with antibacterial activity against Escherichia coli and Staphylococcus aureus.

Cruciferae plants, banana and coriander each showed antibacterial activity. The highest activity among the food-stuffs tested was found in the stems of wasabi. An ethereal extract from wasabi stems had potent antibacterial activity and we isolated the active compound from the extract. Instrumental analysis identified the compound as 6-methylsulfinylhexyl isothiocyanate. Some homologues of 6-methylsulfinylhexyl isothiocyanate were also active against Escherichia coli and Staphylococcus aureus.

4-Hydroxy-3-nitrophenylacetic and Sinapic Acids as Antibacterial Compounds from Mustard Seeds.

A methanol extract from yellow mustard seeds had antibacterial activity against Escherichia coli, Salmonella enteritidis, and Staphylococcus aureus. Two compounds with such activity were isolated from the extract. By instrumental analysis, the compounds were identified as 4-hydroxy-3-nitrophenylacetic and sinapic acids. Examination of the structure-activity relationship showed that the hydroxyl and nitro groups of the first compound were involved in the activity against all three species. The two methoxyl groups and the hydroxyl group in sinapic acid were effective against E. coli and all of the substituents of the benzene ring were effective against S. enteritidis. The presence of the propenoic group of the second compound was effective against S. aureus.

[Cross-reactivity between bromelain and soluble fraction from wheat flour].

It is revealed that patients allergic to a water-soluble fraction from wheat flour were sensitive to pineapple enzyme, bromelain. Since bromelain has a high similarity to other SH-proteases such as papain, it may imply that the patients may recognize varieties of other SH-proteases as the epitope.

Inhibition of basophil histamine release by a haptenic peptide mixture prepared by chymotryptic hydrolysis of wheat flour.

For application to the treatment of wheat-sensitive allergy, we developed a practical method for producing a haptenic peptide mixture, and evaluated its haptenic properties. Wheat flour was hydrolyzed with chymotrypsin to obtain a hydrolysate, and the diffusible fraction from the hydrolysate was subjected to gel-filtration. The resulting oligopeptide fraction could bind to wheat-specific IgE antibodies in the serum of patients allergic to wheat. Since this peptide mixture did not induce histamine release from basophils in these patients, it was concluded that the peptide mixture was composed of monovalent haptens. Histamine release from antigenstimulated basophils was almost completely inhibited when the basophils were preincubated with the haptenic peptide mixture. These results suggest that this haptenic peptide mixture can regulate the allergenic reaction in an epitope-specific manner.