Coffee contains potent opiate receptor binding activity

Abstract

Opiate receptor-active peptide fragments (exorphins) have been identified recently in casein and gluten hydrolysates, and morphine has been found in bovine and human milk. To determine whether similar peptides or alkaloids occur in other foodstuffs, we have screened potential sources using a rat brain homogenate assay to detect opiate receptor activity. We report here that instant coffee powders from a variety of manufacturers compete with tritiated naloxone for binding to opiate receptors in the rat brain membrane preparations, with no significant difference between normal and decaffeinated coffee. The receptor binding activity resembles that seen with opiate antagonists, in that there was no change in the half-maximal effective dose (ED50) in the presence of 100 mM Na+; on bioassay, the activity was similarly shown to be antagonistic and specific for opiate-induced inhibition of twitch. Preliminary characterization of the activity reveals that it has a molecular weight (MW) in the range 1,000-3,500, is heat-stable, ether-extractable, not modified by enzymatic digestion with papain, and clearly separable from caffeine and morphine on TLC. As its concentration in an average cup of coffee is five times the ED50, these data suggest that drinking coffee may be followed by effects mediated via opiate receptors, as well as effects of caffeine.

Reinforcing Effects of Caffeine in Coffee and Capsules

“…This extends a previous observation suggesting the reinforcing effects of decaffeinated coffee: When decaffeinated coffee was substituted for caffeinated coffee on a double-blind basis for 10 or more days, the number of cups of decaffeinated coffee showed only a 3. small, nonsignificant decrease on the first few days after substitution . The extent to which drinking of decaffeinated coffee is maintained by conditioned reinforcers established by past pairing with caffeine or, alternatively, by pharmacologically active substances in coffee other than caffeine (Boublik et al, 1983;Cohen & Booth, 1975;Spiller, 1984) cannot be determined.…”

Determinação de compostos bioativos em amostras comerciais de café torrado

“…Durante a torrefação, ao se degradarem em virtude da reação de pirólise, alguns compostos fenólicos podem produzir lactonas ou quinídeos com propriedades farmacológicas, como afinidade pelos sítios receptores de opióides, conforme verificado em experimentos in vitro 8 .…”

“…Durante as últimas décadas, estudos in vitro e in vivo levaram os pesquisadores a atribuir diferentes funções farmacológicas aos ACG, tais como a ligação a centros opióides do cérebro 8,9 ; atividade inibitória sobre as integrases que participam na replicação do vírus HIV [10][11][12][13][14] ; indução da diminuição dos níveis sanguíneos de glicose, por meio da inibição da enzima glicose-6-fosfatase [15][16][17] ; efeito indutor na replicação e na mobilidade de macrófagos de camundongos, o que acarretaria um aumento da imunidade 18 e característica anti-mutagênica [19][20][21] . Durante o processo de torrefação, esses compostos fenólicos são intensamente degradados, originando pigmentos e componentes voláteis do aroma, como fenol e vinilguaiacol 22,23 .…”

Distribuição de isômeros de ácido clorogênico e teores de cafeína e trigonelina em cafés solúveis brasileiros

“…Em verdade, o café é o único produto alimentício que gera uma vitamina (niacina) durante o processamento [6]. Lactonas de áci-dos clorogênicos apresentam afinidade de ligação em centros opióides do cérebro [1] e isômeros do grupo de ácidos dicafeoilquínicos, apresentam, in vitro, atividade inibitória de integrases na replicação de vírus HIV [9].…”