Radioimmunoassay for the Quantitative Determination of Galanthamine

Abstract

A radioimmunoassay for the quantitation of pmol amounts of the therapeutically important Amaryllidaceae alkaloid, galanthamine, has been developed. The antiserum was raised against a conjugate of galanthamine-2-O-hemisuccinate-bovine serum albumin. The measuring range of the assay extends from 0.5 to 100 ng of galanthamine, and as little as 3.5 pmol may be detected. The antiserum is highly specific for galanthamine, showing practically no cross reactivity with different representatives of the most frequently occurring types of alkaloidal structures in Amaryllidaceae. This assay enables a rapid, sensitive and precise quantitation of galanthamine in unpurified plant extracts. The galanthamine concentration in bulbs of several Leucojum aestivum plants and the distribution of galanthamine in some Amaryllidaceae genera of South African origin have been investigated. Preliminary experiments indicate that the galanthamine-specific radioimmunoassay can be a useful tool in medicinal plant breeding as well as in tissue and cell culture studies.

The chemistry involved in the steam treatment of lignocellulosic materials

“…Finally, at exceedingly high pretreatment temperatures (220-240 °C) and residence times into the steam reactor, condensation reactions involving lignin, (hemi)cellulose-derived by-products and acid-soluble lignin begin to take place, leading to the accumulation of acid-insoluble polymeric materials that barely resemble the structure of lignin itself 48,87,88 . Therefore, steam-exploded lignins are quite extensively modified during pretreatment through mechanisms involving condensation among pretreatment by-products and radicals derived from the homolytic cleavage of arylether bonds 87,89 . This observation has two very important implications.…”

“…The effect of high pressure steaming on the structure and chemical composition of lignin has also been extensively characterized 87,[89][90][91][92][93][94] . Chemical methods aimed at the determination of lignin functional groups such as methoxyl, carboxyl, conjugated and non-conjugated carbonyl, total hydroxyl, and aromatic hydroxyl groups are helpful to characterize the influence of pretreatment on lignin chemistry 89,95 .…”

“…Chemical methods aimed at the determination of lignin functional groups such as methoxyl, carboxyl, conjugated and non-conjugated carbonyl, total hydroxyl, and aromatic hydroxyl groups are helpful to characterize the influence of pretreatment on lignin chemistry 89,95 . However, many of these methods are not only tedious but also susceptible to some interference from other chemical species 95 .…”

“…During steam explosion, lignin is primarily degraded through the homolytic cleavage of β-O-4 ether and other acid-labile linkages, producing a series of cinnamyl alcohols derivatives 89 and condensation by-products ( Figure 5). Release of these low molecular mass compounds gradually increases towards higher pretreatment severities, whose characterization is usually obtained by capillary gas chromatography using mass spectrometry as the principle for detection 89 .…”

“…Release of these low molecular mass compounds gradually increases towards higher pretreatment severities, whose characterization is usually obtained by capillary gas chromatography using mass spectrometry as the principle for detection 89 . Evidence for this pattern of lignin depolymerization has also been obtained by size exclusion chromatography 99 , where increased pretreatment severities caused a gradual decrease in lignin apparent molecular mass without much interference in polydispersity.…”