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Ergot Alkaloids
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
The most dominant alkaloids in grain ergots (sclerotia) are ergotamine, ergocristine, ergosine, ergocornine, and ergocryptine; whereas the most common alkaloids present in forages infected by endophytic fungi are ergovaline and ergine. As alkaloids produced by endophytic fungi are in much lower concentrations than those in Claviceps sclerotia, grazing on endophyte-infected grasses often leads to less severe toxicoses than ingesting grains containing sclerotia [24].
Restricted and Banned Herbals
Published in Amritpal Singh Saroya, Reverse Pharmacology, 2018
Chemical composition: 0.15-0.5% alkaloids. Three classes of ergot alkaloids: the ergotamine group (ergotamine, ergosine and the corresponding isomers) the ergotoxine group (ergocornine, ergocristine, ergokryptine and their isomers) and ergotamine group (ergometrine and its isomer).
Adrenoceptor Antagonists
Published in Kenneth J. Broadley, Autonomic Pharmacology, 2017
The ergotoxin first extracted by Dale was in fact a mixture of ergocornine, ergocristine, α-ergocryptine and β-ergocryptine. Their structures are shown in Table 5.1, together with other ergot alkaloids including ergotamine and ergonovine (ergometrine). These alkaloids are amine derivatives of D-lysergic acid, to which they are converted when hydrolysed. The other products of hydrolysis are either amines, in the case of ergometrine (amine alkaloids), or amino acids, of which one is proline and the other is either phenylalanine, leucine, isoleucine or valine (amino acid alkaloids). The D-isomers are inactive. The amino acid alkaloids are active competitive α-adrenoceptor antagonists with a long duration of action. The amine alkaloids, which lack the amino acid side-chain, such as ergometrine, do not have a-adrenoceptor blocking properties. However, these compounds have a direct smooth muscle stimulant action on the uterus and blood vessels. This property is shared by the amino acid alkaloids and, although once thought to be independent of receptor-mediated events, it is now believed to involve activation of α- and 5-hydroxytryptamine (5-HT) receptors. The contractions of the uterus induced by ergometrine are antagonized by the 5-HT antagonist, cyproheptadine (Hashimoto et al. 1977).
Comparative study on the metabolism of the ergot alkaloids ergocristine, ergocryptine, ergotamine, and ergovaline in equine and human S9 fractions and equine liver preparations
Published in Xenobiotica, 2019
Wiebke Rudolph, Daniela Remane, Dirk K. Wissenbach, Frank T. Peters
Finally, a dealkylation of the ergoline was observed in ergovaline, ergotamine, and ergocryptine. A loss of methyl (–14.0151 Da) was observed for the protonated molecules as well as the fragments m/z 223.1229 and m/z 268.1444 resulting in fragments at m/z 209.1075 as well as m/z 254.1286 as shown for ergocryptine in Figure 4(H). As described for LSD, the demethylation must occur at position N6 of the ergoline structure (Meyer & Maurer, 2011). In accordance with Maurer et al. (1982), the formation of a nor-bromocriptine was not observed in any of the incubation approaches in the present study. Maurer et al. attributed this observation to a steric hindrance by the large neighboring bromine atom (Maurer et al., 1982). However, in the present study ergocristine also showed no N-dealkyl metabolite, although there is no steric hindrance by a bromine atom. A systematic overview of the ergopeptine metabolites is given in Figure 5 exemplified for ergocryptine. The data for each compound under study are given in the supplementary data (Figures S1–S3).