Vegetable and mammalian milk as a source of benzodiazepine-like molecules

One of the challenging questions till facing benzodiazepine (BDZ) researchers is the identification of endogenous BDZ ligands in the brain, which could modulate -aminobutyric acid (GABAA) neurotrasmission. Several substances with benzodiazepine-like activity were found in food. In particular their amount was particularly high in milk. Different type of milk of animal or vegetal origin were analysed by HPLC analysis. The serum obtained by acid precipitation of milk was chromatographed at 0.8 ml/min on a LiChrospher 100 RP-18 column (250x4.0 mm; 5 m) equilibrated with 80% water/0.1% TFA and 20% acetonitrile. The sample was analysed using a water/0.1% TFA and acetonitrile gradient at 0.5% from 20 to 58% acetonitrile. 75 fraction were collected, lyophilised and tested for their ability to inhibit [3H]RO 15-1788 specific binding to central BDZ binding site or [3H]PK 11195 specific binding to peripheral BDZ binding site (PBR). The results are reported in figure. Thermic treatments, like UHT, or the biological procedures do not change the BDZ-like molecules concentration. Since the PBR is involved in cell proliferation the fractions active on PBR were tested on the ability to modulate cell proliferation of hepatocellular carcinoma cell lines (T1). The chronic treatment with the active fraction showed a significant dose-dependent inhibition of T1 cell proliferation indicating a potential use of milk as functional food.