The hop (Humulus lupulus), a component of beer, is a sedative plant whose pharmacological activity is due principally to its bitter resins, especially to the α-acid component 2-methyl-3-buten-2-ol. The mechanism of action of the resin of hop consists of increasing the activity of the neurotransmitter γ-aminobutyric (GABA), inhibiting the central nervous system (CNS). Objectives: To analyze in an experimental model of diurnal animal the sedative effect of hop, a component of beer, on the activity/rest rhythm. Methods: Experiments were performed with common quail (Coturnix coturnix) similar to humans in the sleep-wake rhythm, isolated in 25 × 25 × 25 cm methacrylate cages, with food and water ad libitum, in a room with artificial ventilation (22 ± 1 °C) and a lighting cycle of 12L/12D (n = 5). The doses administered, close to the content of non-alcoholic beer, were 1, 2 and 11 mg extract of hop as one capsule per day, at 18:00 h for one week. A control group received capsules only with a methylcellulose excipient and a basal group received no treatment. The chronobiological analysis of the animals’ activity captured and logged by the software DAS24 was performed using the Ritme computer program (cosinor methods). Results: With the dose of 2 mg, there was a statistically significant (p < 0.05) reduction of the arithmetic mean nocturnal activity (23 ± 3.0) with respect to the basal (38.56 ± 2.79), control (38.1 ± 2.8) and other doses groups 1 mg (52.04 ± 3.65) and 11 mg (47.47 ± 5.88). This dose of 2 mg, similar to the concentration in beer, was more effective in reducing nocturnal activity than the other doses of 1 and 11 mg, as well as preserving the circadian activity/rest rhythm. Conclusion: The concentration of 2 mg of hop extract effectively decreased nocturnal activity in the circadian activity rhythm. On the basis of this investigation, administration of non-alcoholic beer would be recommended due to its hop content and consequent sedative action, which would be an aid to nocturnal sleep.
Sleep deprivation affects the homeostasis of the physiological functions in the human organism. Beer is the only beverage that contains hops, a plant which has a sedative effect. Our objective is to determine the improvement of subjective sleep quality using the Pittsburgh Sleep Quality Index (PSQI). The sample was conducted among a population of 30 university students. The study took place during a period of 3 weeks, the first 7 days were used for the Control, and during the following 14 days the students ingested beer (were asked to drink non-alcoholic beer) while having dinner. The results revealed that Subjective Sleep Quality improved in the case of those students who drank one beer during dinner compared to the Control, this is corroborated by the fact that Sleep Latency decreased (p < 0.05) compared to their Control. The overall rating Global Score of Quality of Sleep also improved significantly (p < 0.05). These results confirm that the consumption of non-alcoholic beer at dinner time helps to improve the quality of sleep at night.
The use of melatonin as antioxidant has been extensively established. But what would the antioxidant function be if one were to go one step back in the anabolism of that amine, and orally administer its precursor — the amino acid tryptophan? Diurnal animals (
) were administered orally capsules containing 125 or 300 mg L-tryptophan/kg b.w. for 7 days at the end of the light period (20
). A control group received capsules with methylcellulose. The antioxidant function was studied through the reduction of nitroblue tetrazolium (NBT) by superoxide anion, and through the levels of malonaldehyde (MDA) produced in the lipoperoxidation that occurs from the respiratory burst in response to the presence of a foreign particle in phagocytic cells (heterophils), which were extracted at 2
— at the acrophase of melatonin in the blood stream. In the heterophils extracted from the group that received 125 mg kg
b.w. tryptophan, there was less oxidative stress as determined by the NBT reduction than in those from the 300 mg kg
b.w. group. In the study of the lipoperoxidation of the membranes as determined by the levels of MDA, however, no significant variations were observed between the different groups. The lower concentration (125 mg L-tryptophan/kg b.w.), administered orally, succeeded in diminishing the free radicals produced in the heterophils for the destruction of the ingested foreign agent, but not fully or maximally. The possible solution to this prooxidant/antioxidant imbalance would be to administer a lower concentration of tryptophan to attain the perfect balance for application in nutritional treatments.
The objective of the present study was to compare differences between elderly rats and young obesity-induced rats in their activity/inactivity circadian rhythm. The investigation was motivated by the differences reported previously for the circadian rhythms of both obese and elderly humans (and other animals), and those of healthy, young or mature individuals. Three groups of rats were formed: a young control group which was fed a standard chow for rodents; a young obesity-induced group which was fed a high-fat diet for four months; and an elderly control group with rats aged 2.5 years that was fed a standard chow for rodents. Activity/inactivity data were registered through actimetry using infrared actimeter systems in each cage to detect activity. Data were logged on a computer and chronobiological analysis were performed. The results showed diurnal activity (sleep time), nocturnal activity (awake time), amplitude, acrophase, and interdaily stability to be similar between the young obesity-induced group and the elderly control group, but different in the young control group. We have concluded that obesity leads to a chronodisruption status in the body similar to the circadian rhythm degradation observed in the elderly.