M. L. Zeneroli

Natural endogenous ligands for benzodiazepine receptors in hepatic encephalopathy.

Benzodiazepines of natural origin (NBZDs) have been found in human blood and brains as well as in medicinal plants and foods. In plasma and brain tissue there are i.e. diazepam and nordiazepam equal to commercial drugs but there are also other benzodiazepine-like compounds termed “endozepines”, which act as agonists at the benzodiazepine receptors of central type (CBR). A synthetic pathway for the production of NBZDs has not yet been found, but it has been suggested that micro-organisms may synthesize molecules with benzodiazepine-like structures. Hence NBZDs could be of both endogenous and exogenous source and be considered as natural anxyolitic and sedative. Interestingly there are also natural compounds, such as the polypeptide Diazepam Binding Inhibitor (DBI) acting as an “inversive agonist” implicated in fair and panic disorders. It has been suggested that NBZDs may play a role in the pathogenesis of hepatic encephalopathy (HE). Multidirectional studies evaluated NBZDs levels (1) in the blood of normal subjects, of cirrhotic with or without HE and in commercial benzodiazepine consumers; (2) in the blood of cirrhotic treated or not with a non-absorbable antibiotic; (3) in several constituents of our diet. In conclusion, NBZDs increase sometime in cirrhotics with or without HE but they reach concentrations not higher than those found in commercial benzodiazepines consumers. Hence NBZDs must be considered as occasional precipitating factor of HE and benzodiazepine antagonists only symptomatic drugs. The finding that NBZDs may be in part synthesized by intestinal bacterial flora and in part constituent of our diet underlines the importance to feed cirrhotic patients with selected food.

Presence of benzodiazepine-like molecules in food and their implication in the nutrition of cirrhotic patients

Abstract Benzodiazepine (BDZ)-like compounds, present in trace amounts in normal subjects increase in the blood of liver cirrhotic patients. The origin of these compounds is still unknown but they are present in medicinal plants and foods. Herein we report the detection of BDZ-like molecules in fruits, vegetables, cereals, meat, milk and cheeses and in different cultivars of potatoes, tomatoes and carrots. The extracted food was separated by HPLC purification and the collected fractions were tested by radioreceptor binding assay in order to evaluate their ability to selectively bind the central benzodiazepine receptors. The mean value was 14.80 ng of diazepam equivalent (DE)/g in fruits, 4.34 ng DE/g in vegetables, 6.35 in cereals and 4.09 in meat. BDZ-like compounds are poorly present in cheeses and completely absent in olive and seeds oil. From these findings it is possible to select food with low amount of BDZ-like molecules useful for cirrhotic diet in order to prevent hepatic encephalopathy.

Ammonia and 1,4-benzodiazepines in encephalopathic patients with fulminant hepatic failure

AMMONIA AND 1,4-BENZODIAZEPINES IN ENCEPHALOPATHIC PATIENTS WITH FULMINANT HEPATIC FAILURE. M.L. Zeneroli*, I. Venturini*, L, Corsi °, R. Avallone °, F. Farina*, G. Ardizzone , M. Centanaro , A. Arrigo , L. Miglioli*, P. Schreier**, M. Kleinschnitz**, and M. Baraldi °. *Cattedra di Semeiotica e Metodologia Medica e °Dip. Scienze Farmaceutiche Universit~t di Modena; ^Centro Trapianti Universit~ di Genova, Italy; and **Lehrstuhlfur Lebensmittelchemie Universiflit Wtirzburg, Germany.