Purpose.We aimed to investigate the possible effects of melatonin on gene expressions and activities of MnSOD and catalase under conditions of oxidative stress induced by hydrogen peroxide (H₂O₂) in peripheral blood mononuclear cells (PBMCs).Materials and Methods.PBMCs were isolated from healthy subjects and treated as follows: (1) control (only with 0.1% DMSO for 12 h); (2) melatonin (1 mM) for 12 h; (3) H₂O₂(250 μM) for 2 h; (4) H₂O₂(250 μM) for 2 h following 10 h pretreatment with melatonin (1 mM). The gene expression was evaluated by real-time PCR. MnSOD and catalase activities in PBMCs were determined by colorimetric assays.Results.Pretreatment of PBMCs with melatonin significantly augmented expression and activity of MnSOD which were diminished by H₂O₂. Melatonin treatment of PBMCs caused a significant upregulation of catalase by almost 2-fold in comparison with untreated cells. However, activity and expression of catalase increased by 1.5-fold in PBMCs under H₂O₂-induced oxidative stress compared with untreated cell. Moreover, pretreatment of PBMCs with melatonin resulted in a significant 1.8-fold increase in catalase expression compared to PBMCs treated only with H₂O₂.Conclusion.It seems that melatonin could prevent from undesirable impacts of H₂O₂-induced oxidative stress on MnSOD downregulation. Moreover, melatonin could promote inductive effect of H₂O₂on catalase mRNA expression.

Background and the purpose of the study: Melatonin has recently been found in several plant tissues. Some reports show that the majority of the herbs containing the high level of melatonin have been used traditionally to treat neurological disorders or diseases associated with the generation of free radicals. Current study was undertaken to screen some medicinal plant species with historical evidence of efficacy in the treatment of neurological and antioxidant deficiency related disorders for their melatonin content. The melatonin content of boiled and alcoholic extracts were also compared. Methods: In this study, three medicinal herbs, Tanacetum parthenium (L.) Schultz. Bip. (Asteraceae), Tripleurospermum disciforme (C.A.Mey) Schultz. Bip. (Asteraceae) and Viola odorata (L.) (Violaceae) were analyzed using high performance liquid chromatography with ultraviolet detector (HPLC-UV), enzyme linked immunosorbent assay (ELISA) and thin layer chromatography (TLC). Results: Melatonin content in the dry plant powders differed with different assay methods (p < 0.001). For example, the melatonin content in T disciforme was determined as 3.073 mu g/g and 2.906 mu g/g by the HPLC and the ELISA methods, respectively. Major conclusion: The results demonstrated that a hydroalcoholic solution could extract more melatonin from flowers of the herbs than hot water (p < 0.001). The presence of melatonin in these plant tissues may provide some explanation for the anecdotal evidence of their physiological effects in humans.

Objective(s): The neuropeptide calcitonin gene-related peptide (CGRP) has long been postulated to play an integral role in the pathophysiology of migraine. Earlier studies showed that CGRP can stimulate the synthesis and release of nitric oxide (NO) and cytokines from trigeminal ganglion glial cells. The purpose of this study was to determine the effect of 17 beta-estradiol in regulation of CGRP expression, inducible nitric oxide synthase (iNOS) activity, and NO and interleukin-1beta (IL-1 beta) release in cultured peripheral blood mononuclear cells (PBMCs) from patients with pure menstrual migraine and healthy individuals. Materials and Methods: This study was performed on twelve patients with pure menstrual migraine and twelve age-and sex-matched healthy individuals. PBMCs treated with 17 beta-estradiol for 24 hr at physiological and pharmacological doses. Gene expression was evaluated by real time-PCR. CGRP and IL-1 beta proteins in culture supernatant were determined by ELISA method. Activity of iNOS in PBMCs and total nitrite in the culture supernatant were measured by colorimetric assays. Results: Treatment with 17 beta-estradiol had a biphasic effect on expression of CGRP. We found that 17 beta-estradiol treatment at pharmacological dose significantly increases mRNA expression of CGRP in both groups (P<0.001), whereas at physiological dose it could significantly decrease CGRP mRNA expression (P<0.001), CGRP protein levels, IL-1 beta release, NO production and iNOS activity only in patient groups (P<0.05). Conclusion: Collectively, it appears that 17 beta-estradiol can exert protective effect on decrease of inflammation in migraine via decrease in levels of CGRP, IL-1 beta and iNOS activity; however, more studies are necessary in this regard.