Modern epidemiological and interventional studies have demonstrated that various bioactivities including antioxidant, antiproliferative, immune-regulatory, hormonal-regulation abilities and neuro-/hepato-/cardioprotective effects result from consumption of a phenolic-rich diet. The health benefits of ingesting phenolics are greatly dependent on their bioaccessibility and bioavailability in the digestive tract and circulatory system. This contribution attempts to review the bioaccessibility and bioavailability of phenolic compounds by focusing on the body’s internal mechanism including digestion, absorption, transport, modification, excretion, and colonic fermentation. The bioaccessibility and bioavailability of different phenolics vary depending on the physical condition of an individual, including digestive/absorptive/metabolic/response capability and effective dose. External factors such as processing methods and interaction with various food matrices also play a vital role on the bioavailability of dietary phenolic compounds. On the other hand, some novel phenolics have been synthesized to enable them rendering new bioactivities. The key internal factors influencing the bioaccessibility and bioavailability are also reviewed in this contribution. In addition, suggestions have been made for future measurement and assessment of bioavailability, together with prospects for food/nutraceutical/pharmaceutical application of novel phenolics.

Phenolic compounds constitute a large and diverse group of secondary metabolites derived from phenylalanine and tyrosine and are widely distributed throughout the plant kingdom. They could be divided into different classes such as simple phenol, phenyl acetic acid, hydroxybenzoic acid, hydroxycinnamic acid, and other phenylpropanoids as well as condensed tannins (proanthocyanidins) and hydrolysable tannins, among others, depending on their basic carbon skeleton structure. Phenolic compounds in plant-based foods have been suggested to have a number of beneficial health effects including prevention of cancer, cardiovascular disease, diabetes, immune disorders, neurogenerative disease and others. These properties are largely attributable to the antioxidant activity of the phenolic compounds as well as other mechanisms of action. Therefore, nutraceuticals of plant origin may evolve to be considered a vital aspect of dietary-disease preventive food components. Agri-food industries generate substantial quantities of phenolic rich by-products, which could serve as an attractive and commercially viable source of nutraceuticals. This contribution mainly summarizes the occurrence of phenolic compounds and some other bioactives in various Agri-food by-products, their bioavailability and health benefits.

Lentils contain a plethora of bioactive phytochemicals such as extractable and insoluble-bound phenolics, carotenoids, tocopherols, saponins, phytic acid, and phytosterols, which have been increasingly attributed to the health benefits of lentil consumption in the diet. The concentration and stability of these phytochemicals in lentils may be affected by several processing parameters including different thermal processing, exogenous enzyme treatment and germination. Consumption of lentils has been associated with the risk reduction of many diseases due to the potential antioxidant activity and anti-inflammatory potential of phytochemicals in lentils. This mini review is intended to provide most current information on the phytochemical composition of lentils, and the potential antioxidant and anti-inflammatory properties of these compounds.