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A key perception of energy homeostasis is the recognition of a mutual regulation between biological clock and cell metabolism. For instance, the regular occurrences of appetite and satiety is not incessant over 24 h, but is instead organized temporally over the 24 h and the light/dark cycle. In mammals, the temporal regulation of metabolism, physiology and behaviour about 24 h is regulated by a complex system of manifold cellular clocks, synchronized via neuronal and hormonal cues by a master clock situated in the suprachiasmatic nuclei of the hypothalamus. Chronic disturbance of circadian rhythms, as seen in human shift-workers (up to 20% of the dynamic populace), has been linked with the advancement of numerous unfavourable mental and metabolic disturbances, suggesting that metabolic processes and biological clock are tightly linked with each other. Comprehension of the functional associations among circadian desynchronization and general health in animal model systems and humans, nevertheless, is still meagre. To sum up, this research topic covers a broad assortment of functional connections amid circadian rhythms and metabolism at molecular, cellular, tissue, organ and organism level. [ABSTRACT FROM AUTHOR]

Rhythmicity is observed in transcriptional expression of a wide range of clock-controlled genes which regulate a variety of normal cell functions like cell division and proliferation. The human circadian timing system functions to co-ordinate humoral, physiological, and behavioral mechanism to promote sleep and waking behavior. The rhythms are generated by neural structures in the hypothalamus that function as a biological clock. Modern lifestyle is also turning to be a relevant factor promoting desynchrony, especially in individuals staying for long hours awake during the night and with disturbed sleep patterns. Chronotherapeutics is relatively new concept in medicine. The main goal of chronotherapeutics is the enhancement of the desired effects of medications and control of their adverse effects. This review addresses the role of circadian rhythms in tumorigenesis. [ABSTRACT FROM AUTHOR]

Cancer is still one of the major causes of mortality in both developing and developed countries. At present, in spite of intensive interventions, a large number of patients suffer from poor prognosis. Also, regarding some phytochemicals, only beneficial effects on cancer-related symptoms or on quality of life have been reported and no positive results exist for their antitumor actions. This review was focused on the phytochemicals whole beneficial effects on various types of cancer have been supported by clinical trials. This review discusses how a disruption of the "biological clock" or circadian rhythms could be involved in the development of these diseases as circadian rhythms control multiple physiological processes such as wake/sleep cycles, hormonal levels, body temperature, metabolism, and immune system. [ABSTRACT FROM AUTHOR]

Sleep-wake cycle is the predominant example of circadian rhythms. Melatonin is commonly used to treat insomnia and in additional neurodevelopmental disorders in which sleep disturbance is frequent. In mammals, melatonin receptors are present in the membrane and cell nucleus of many tissues and systems where it exhibits various actions, including the regulation of circadian rhythms. The rhythmic pattern of melatonin secretion is imperative since it endows with vital information to the organism concerning time, which permits for alterations of a number of physiological functions consistent with daily and seasonal variations. Melatonin as well has sleep promoting effects demonstrated in changes in brain activation patterns and tiredness generation. The SCN's (suprachiasmatic nuclei) function and melatonin production capability turns down with age consequently depriving the brain from an important time cue and sleep regulator. [ABSTRACT FROM AUTHOR]

Disorganized redox homeostasis is a main factor causing a number of diseases and it is imperative to comprehend the orchestration of circadian clock under oxidative stress in the organism, Drosophila melanogaster. This investigation analyses the influence of hesperidin on the circadian rhythms of lipid peroxidation products and antioxidants during rotenone-stimulated oxidative stress in fruit fly. The characteristics of rhythms of thiobarbituric acid reactive substances (TBARS), antioxidants (superoxide dismutase (SOD) and catalase (CAT)) were noticeably decreased in rotenone administered flies. Supplementation of hesperidin to rotenone-treated flies increased the mesor and modulated the amplitudes of antioxidants and conspicuously decreased the mesor values of TBARS. In addition, delays in acrophase in rotenone-induced flies were reversed by hesperidin treatment. Thus, treatment of hesperidin caused normalization of the altered rhythms. Disorganization of 24 h rhythms in markers of redox homeostasis was observed during rotenone treatment and the impairment is severe in circadian clock mutant (Cryb) flies. Reversibility of rhythms was prominent subsequent to hesperidin treatment in wild-type flies than (Cryb) flies. These observations denote a role of circadian clock in redox homeostasis and the use of Drosophila model in screening putative antioxidative phytomedicines prior to their usage in mammalian systems. [ABSTRACT FROM PUBLISHER]