Melatonin is a pleotropic molecule with numerous biological activities. Epidemiological and experimental studies have documented that melatonin could inhibit different types of cancer in vitro and in vivo. Results showed the involvement of melatonin in different anticancer mechanisms including apoptosis induction, cell proliferation inhibition, reduction in tumor growth and metastases, reduction in the side effects associated with chemotherapy and radiotherapy, decreasing drug resistance in cancer therapy, and augmentation of the therapeutic effects of conventional anticancer therapies. Clinical trials revealed that melatonin is an effective adjuvant drug to all conventional therapies. This review summarized melatonin biosynthesis, availability from natural sources, metabolism, bioavailability, anticancer mechanisms of melatonin, its use in clinical trials, and pharmaceutical formulation. Studies discussed in this review will provide a solid foundation for researchers and physicians to design and develop new therapies to treat and prevent cancer using melatonin.

Introduction Macrophages constitute a heterogeneous population of functionally distinct cells involved in several physiological and pathological processes. They display remarkable plasticity by changing their phenotype and function in response to environmental cues representing a spectrum of different functional phenotypes. The so-called M1 and M2 macrophages are often considered as representative of pro-and anti-inflammatory ends of such spectrum. Metabolomics approach is a powerful tool providing important chemical information about the cellular phenotype of living systems, and the changes in their metabolic pathways in response to various perturbations. Objectives This study aimed to characterise M1 and M2 phenotypes in THP-1 macrophages in order to identify characteristic metabolites of each polarisation state. Methods Herein, untargeted liquid chromatography (LC)-mass spectrometry (MS)-based metabolite profiling was applied to characterise the metabolic profile of M1-like and M2-like THP-1 macrophages. Results The results showed that M1 and M2 macrophages have distinct metabolic profiles. Sphingolipid and pyrimidine metabolism was significantly changed in M1 macrophages whereas arginine, proline, alanine, aspartate and glutamate metabolism was significantly altered in M2 macrophages. Conclusion This study represents successful application of LC-MS metabolomics approach to characterise M1 and M2 macrophages providing functional readouts that show unique metabolic signature for each phenotype. These data could contribute to a better understanding of M1 and M2 functional properties and could pave the way for developing new therapeutics targeting different immune diseases.

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Background The relationship between smoking and coronavirus disease-2019 (COVID-19) is still topical with mixed epidemiological evidence. However, the pandemic may affect people’s beliefs toward smoking as well as their smoking behavior and quit intentions. Considering high smoking rates in Jordan, our current study aimed to assess the following domains in a community-based sample from Jordan: (i) the beliefs that surround smoking/vaping and COVID-19 and (ii) the pandemic impact on smoking behavior and quit intention. Methods A cross-sectional study was conducted in Jordan from March 9 to March 16, 2021, utilizing a web-based structured questionnaire. The questionnaire comprised 13 items on sociodemographic, health, and smoking profiles, 14 items to assess beliefs surrounding COVID-19 and the use of combustible cigarettes (CCs), waterpipe (WP), and electronic cigarettes (ECs), and 12 items to assess the pandemic impact on smoking behavior and quit intention. Results Of 2424 survey respondents who participated in our study, there were 1163 never-smokers, 1044 current smokers, and 217 ex-smokers. The mean age of participants was 35.2 years (SD: 11.06). Most participants have reported anti-smoking beliefs with around 72.9% believed that WP smoking is related to the risk of contracting COVID-19. Also, 71.7% believed that smoking CC may worsen the COVID-19 clinical course, while 74.1% of respondents believed that smoking has no protective effect against COVID-19. During the pandemic, about 28.1% and 19.3% of current smokers reported increased or reduced smoking, respectively. Besides, 459 current smokers have expressed their plans/intention to quit smoking during the pandemic, of whom 27.5% (n = 126) confirmed that the driving force for their decision is a COVID-19-related reason, such as self-protection (n = 123) and protection of family members (n = 121) which were the most cited reasons. Also, around 63 participants have successfully ceased smoking during the pandemic. However, only 22 of them reported that the main driving motivation of their successful quit attempt was the COVID-19 pandemic. Conclusion Most participants’ beliefs and attitudes were against smoking during the pandemic. Nevertheless, the double-edged effect of the pandemic on smoking habits should be carefully considered, and reliable anti-smoking measures should be strengthened and sustained in the country.