Stereospecific analysis of lorazepam in plasma by chiral column chromatography with a circular dichroism-based detector

1. Erabutoxins, a, b and c, neurotoxic proteins of a sea snake Lacticauda semifasciata, were guanidinated with O-methylisourea. The amino groups of all the lysine residues and those at the N-termini of the toxins were modified. The lethal activity of the toxins decreased to 50% (erabutoxins a and b) or 17% (erabutoxin c) of the original value on the modification. The c.d. (circular dichroism) maximum at 227 nm of the modified toxins became lower, whereas the whole profile of the c.d. curve remained unchanged. 2. The amino groups of erabutoxin b were acetylated with acetic anhydride. All the five monoacetyl derivatives were isolated from the reaction products by CM-cellulose and Bio-Rex 70 column chromatography. [1-Nalpha-acetylarginine]-, [15-N6-acetyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b retained the toxicity of the native toxin, whereas [27-N6-acetyl-lysine] and [47-N6-acetyl-lysine]-erabutoxin b were 17 and 8% active respectively. The overall profile of c.d. spectrum of erabutoxin b remained unchanged on the monoacetylation.

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Three New Phthalide Glycosides from the Rhizomes of Cnidium officinale and Their Recovery Effect on Damaged Otic Hair Cells in Zebrafish

Molecules ◽

10.3390/molecules26227034 ◽

2021 ◽

Vol 26 (22) ◽

pp. 7034

Author(s):

Hyoung-Geun Kim ◽

Seon Min Oh ◽

Na Woo Kim ◽

Ji Heon Shim ◽

Youn Hee Nam ◽

...

Keyword(s):

Circular Dichroism ◽

Column Chromatography ◽

Hair Cells ◽

Spectroscopic Data ◽

Recovery Effect ◽

Active Fraction ◽

Chemical Structures ◽

Cnidium Officinale ◽

Circular Dichroïsm

The extract from Cnidium officinale rhizomes was shown in a prior experiment to markedly recover otic hair cells in zebrafish damaged by neomycin. The current study was brought about to identify the principal metabolite. Column chromatography using octadecyl SiO2 and SiO2 was performed to isolate the major metabolites from the active fraction. The chemical structures were resolved on the basis of spectroscopic data, including NMR, IR, MS, and circular dichroism (CD) data. The isolated phthalide glycosides were assessed for their recovery effect on damaged otic hair cells in neomycin-treated zebrafish. Three new phthalide glycosides were isolated, and their chemical structures, including stereochemical characteristics, were determined. Two glycosides (0.1 μM) showed a recovery effect (p < 0.01) on otic hair cells in zebrafish affected by neomycin ototoxicity. Repeated column chromatography led to the isolation of three new phthalide glycosides, named ligusticosides C (1), D (2), and E (3). Ligusticoside C and ligusticoside E recovered damaged otic hair cells in zebrafish.

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Characterization of Tamm-Horsfall Urinary Glycoprotein

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007254x ◽

1973 ◽

Vol 31 ◽

pp. 420-421

Author(s):

John P. Robinson ◽

J. David Puett

Keyword(s):

Electron Microscopy ◽

Circular Dichroism ◽

Secondary Structure ◽

Quaternary Structure ◽

Normal Adult ◽

Morphological Properties ◽

Adult Males ◽

Circular Dichroïsm ◽

Urinary Glycoprotein

Much work has been reported on the chemical, physical and morphological properties of urinary Tamm-Horsfall glycoprotein (THG). Although it was once reported that cystic fibrotic (CF) individuals had a defective THG, more recent data indicate that THG and CF-THG are similar if not identical.No studies on the conformational aspects have been reported on this glycoprotein using circular dichroism (CD). We examined the secondary structure of THG and derivatives under various conditions and have correlated these results with quaternary structure using electron microscopy.THG was prepared from normal adult males and CF-THG from a 16-year old CF female by the method of Tamm and Horsfall. CF female by the method of Tamm and Horsfall.

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