Role of Melatonin in Cancer Treatment

Abstract Melatonin is a methoxyindole synthesized and secreted principally by the pineal gland at night under normal environmental conditions. The endogenous rhythm of secretion is generated by the suprachiasmatic nuclei and entrained to the light/dark cycle. The primary physiological function of melatonin, whose secretion adjusts tonight length, is to convey information concerning the daily cycle of light and darkness to body physiology. It is secreted during darkness and plays a key role in various physiological responses, including regulation of circadian rhythms, sleep homeostasis, retinal neuromodulation and vasomotor responses. Melatonin also enhances the antioxidant potential of the cell by stimulating the synthesis of antioxidant enzymes, including superoxide dismutase, glutathione peroxidase and glutathione reductase, and by augmenting glutathione levels. Melatonin plays a role in mammary cancer by down-regulating some of the pituitary and gonadal hormones that control mammary gland development and which are also responsible for the growth of hormone-dependent mammary tumors. Furthermore, melatonin could act directly on tumoral cells, as a naturally occurring antiestrogen, thereby influencing their proliferative rate. Key words: Melatonin; Mammary cancer; pineal gland; suprachiasmatic nuclei Introduction Melatonin is an indolic hormone mainly secreted by the pineal gland. Secondary sources are retina, gut, skin, platelets, bone marrow and probably other structures, whose systemic contribution is insignificant. This aspect and the fact that it lightens the frog skin by contracting melanophores led to the naming of this molecule as Melatoni

Toxic effect of khat (Catha edulis) on memory: Systematic review and meta-analysis

Background: People use khat (Catha edulis) for its pleasant stimulant effect of physical activity, consciousness, motor, and mental functions. Although there are reports assessing the effect of khat on memory, there was no study based on formal systematic review and meta-analysis. Objective: We have therefore conducted this meta-analysis to determine the level of evidence for the effect of khat (C. edulis Forsk) on memory discrepancy. Methods: MEDLINE, Cochrane Library, PubMed, Academic Search Complete, SPORTDiscus, ScienceDirect, Scopus, Web of Science, and Google Scholar were searched to retrieve the papers for this review. Keywords utilized across database search were khat, cat, chat, long-term memory, short-term memory, memory deficit, randomized control trial, and cross-sectional survey. The search was limited to studies in humans and rodents; published in English language. Result: Finding of various studies included in our meta-analysis showed that the effect of acute, and subchronic exposure to khat showed that short-term memory appears to be affected depending on the duration of exposure. However, does not have any effect on long-term memory. Conclusion: Although a number of studies regarding the current topic are limited, the evidenced showed that khat (C. edulis) induced memory discrepancy