The aim of this special issue on "Bioactive Compounds of Food: Their Role in the Prevention and Treatment of Diseases" is to provide a representation of the new trends of bioactive compounds of food involved in different pathologies. Food bioactive compounds are extranutritional constituents that typically occur in small quantities in foods. In summary, numerous bioactive compounds appear to have beneficial health effects. Much scientific research needs to be conducted before we can begin to make science-based dietary recommendations. Despite this, there is sufficient evidence to recommend consuming food sources rich in bioactive compounds. From a practical perspective, this translates to recommending a diet rich in a variety of fruits, vegetables, whole grains, legumes, oils, and nuts. Therefore, the current issue will be focused on identifying as well as understanding the mechanistic role of food bioactive compounds in a range of human pathologies. This issue is logically divided into four main areas: (a) bioactive compounds and inflammation, (b) functional food in chronic diseases, (c) bone health and polyphenols, and (d) neuroprotective effects of bioactive compounds. Forty-four papers were selected through our routine rigorous double-blind external peer review by qualified experts. Due to the capacity limitation, some papers have already appeared earlier in the last issue (volume 2019, No. 2019). Some papers are briefly introduced below.

Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound’s action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines.

Colorectal cancer is a major cause of morbidity and mortality throughout the world. Issues related to the role of diet in cancer prevention and treatment are featured each year, and, in this context, consumption of hydroxycinanmic acids is associated with reduced risk of chronic diseases including cancer. Therefore, the aim of this study was to evaluate the cellular uptake of caffeic and 5-caffeoylquinic acids and their effects on cell viability, cell cycle, and apoptosis in human colon adenocarcinoma cells (HT-29). HT-29 cells were incubated with different concentrations of caffeic and 5-caffeoylquinic acids (1.25 µM to 80.0 µM) from 0.5 to 96 h. Cellular uptake was analyzed by HPLC and LCMS. Cell viability, cell cycle, and apoptosis was measured, respectively, using MTT method and flow cytometry. Caffeic and 5-caffeoylquinic acids are absorbed, isomerized, and metabolized by HT-29 cells. Both compounds were able to reduce HT-29 cell viability, promoting specific changes in the cell cycle and increased the apoptosis rate. Caffeic acid and 5-caffeoylquinic acid showed inhibitory effects on cell growth, suggesting a modulation of the cell cycle with an increase in apoptosis in human colon adenocarcinoma cells.

Hydroxycinnamic acid compounds are an important source of antioxidants due to their ubiquitous occurrence in the plant kingdom and their characteristic activities. Due to their antioxidant activity, several researchers have attributed a probable role of these compounds in the prevention of various diseases associated with oxidative stress, such as cancer and cardiovascular diseases. Recent evidence suggests that these compounds may also act by other mechanisms in addition to the antioxidant capacity as modulating the activity of some specific enzymes and inhibit cell proliferation. This paper is a comprehensive review of the effects of hydroxycinnamic acids on cancer. The review encompasses the occurrence and bioavailability of these compounds evidences for their effects on cancer and the various mechanisms by which may exert their effects. There are several common mechanisms by which these chemicals exert their effects that could be conducive to additive, synergistic, or antagonistic interactions. These include effects on cellular differentiation, proliferation, and apoptosis; effects on proteins and enzymes that are involved in these processes at a molecular level, and other various effects through altered immune function and chemical metabolism.