Branca M. Silva

White Tea (Camellia Sinensis (L.)): Antioxidant Properties and Beneficial Health Effects

Tea is one of the most widely consumed beverages in the world, next to water. It can be categorized into three major types, depending on the level of fermentation, i.e., green and white (unfermented), oolong (partially fermented) and black (fermented) tea. Each type of tea has a dis- tinct composition, dependent on how the leaves are processed, as well as maturation, geographical location and agricultural practices. White tea (WT), the least processed tea, is one of the less studied and is ascribed to have the highest content of phenolic compounds. Tea polyphenols, especially catechin derivatives, are potent antioxidant agents, with positive effects on human health. Antioxidant components have aroused great interest because of their ability to scavenge free radicals, thereby inhibiting oxidative stress. During the past years, oxidative damage induced by reactive species has been linked to the development of several human diseases such as cardiovascular diseases, diabetes mellitus, neurodegenera- tive disorders and certain types of cancer. Therefore, tea antioxidants may be of great value in preventing the onset and/or the progression of oxidative stress mediated diseases, when endogenous defences are insufficient against reactive species. The possible beneficial health effects of WT are being investigated and have received considerable attention in recent years. In this review, we aim to explore the new findings concern- ing WT effects on health.

Bioactive compounds of citrus as health promoters

Different chestnut species can be cultivated for fruit production, the most valorised part for nutritional purposes. However Castanea sativa Mill., the “European chestnut”, is one of the most valorised worldwide. Its fruits are consumed either raw or after processing, being boiling and roasting the most usual ones. The nutritional composition of fresh chestnut is variable, with interesting amounts of carbohydrates and fibre, together with low fat content, with differences between cultivars and producing regions. In respect to the presence of bioactive compounds, such as phenolic compounds, vitamins, fatty acids, among others, some studies had focused on the fruit benefits to human health but few reported the effect of processing in those compounds. In this context, this chapter intended to review the current knowledge on chestnut composition, together with the influence of diverse post-harvest technologies, such as refrigeration, flame peeling, freezing with CO2, irradiation, boiling and roasting on the bioactive compounds of chestnut.

Pineal Gland and Regulatory Function

The pineal gland controls the biological rhythms dependent of the light/dark cycle mainly through the levels of melatonin released into the blood during that cycle. This multitasking molecule has a key role in reproduction and reproductive processes of males and females and interacts with hypothalamic–pituitary–ovarian and the hypothalamic–pituitary–testis axes. Thus, pineal gland has emerged as a relevant regulatory organ of several physiological functions. Herein we discuss the pineal gland regulatory functions, with emphasis on reproductive events.

Pineal Gland and Melatonin Biosynthesis

The anatomical features of the pineal gland show that it has a central role in the individuals health. The most remarkable function of this gland is melatonin biosynthesis, which is a very complex process. Melatonin carries the information concerning photoperiod that is then differently used by the cells, tissues and even has a species-dependent action. Herein we discuss pineal gland physiology and the process of melatonin biosynthesis, with emphasis on how it mediates the several known biological actions for melatonin.