Bioactive peptides (BAPs), derived through enzymatic hydrolysis of food proteins, have demonstrated potential for application as health-promoting agents against numerous human health and disease conditions, including cardiovascular disease, inflammation, and cancer. The feasibility of pharmacological application of these peptides depends on absorption and bioavailability in intact forms in target tissues, which in turn depends on structure of the peptides. Therefore, production and processing of peptides based on important structure-function parameters can lead to the production of potent peptides. This article reviews the literature on BAPs with emphasis on strategic production and processing methods as well as antihypertensive, anticancer, anticalmodulin, hypocholesterolemic, and multifunctional properties of the food protein-derived peptides. It is recommended that future research efforts on BAP should be directed toward elucidation of their in vivo molecular mechanisms of action, safety at various doses, and pharmacological activity in maintaining homeostasis during aberrant health conditions in human subjects.

The amino acid composition and antioxidant activities of peptide fractions obtained from HPLC separation of a pea protein hydrolysate (PPH) were studied. Thermolysin hydrolysis of pea protein isolate and ultrafiltration (3 kDa molecular weight cutoff membrane) yielded a PPH that was separated into five fractions (F1-F5) on a C(18) reverse phase HPLC column. The fractions that eluted later from the column (F3-F5) contained higher contents hydrophobic and aromatic amino acids when compared to fractions that eluted early or the original PPH. Fractions F3-F5 also exhibited the strongest radical scavenging and metal chelating activities; however, hydrophobic character did not seem to contribute to reducing power of the peptides. In comparison to glutathione, the peptide fractions had significantly higher (p < 0.05) ability to inhibit linoleic acid oxidation and chelate metals. In contrast, glutathione had significantly higher (p < 0.05) free radical scavenging properties than the peptide fractions.

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Simulated gastrointestinal hydrolysis of hemp seed proteins using pepsin and pancreatin followed by membrane ultrafiltration fractionation yielded fractions with peptide sizes of\1, 1-3, 3-5, and 5-10 kDa. Analysis of in vitro antioxidant properties showed that the hemp seed protein hydrolysate (HPH) exhibited a significantly weaker (p \ 0.05) scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals when compared to the fractionated peptides. Metal chelation activity of the HPH was significantly greater (p \ 0.05) than the activities of fractionated peptides. Fractionation of the HPH led to significant (p \ 0.05) improvements in ferric reducing power, DPPH, and hydroxyl radical scavenging radical activities but decreased metal chelation capacity. Peptide fractions with longer chain lengths (3-5 and 5-10 kDa) had better metal chelation and ferric reducing power than the \1, and 1-3 kDa fractions. HPH and all the peptide fractions significantly inhibited (p \ 0.05) linoleic acid oxidation when compared to the control. Glutathione (GSH) had significantly greater (p \ 0.05) ferric reducing power, and scavenging of hydroxyl and DPPH radicals when compared to HPH and fractionated peptides. In contrast, HPH and peptide fractions [3 kDa had significantly higher (p \ 0.05) metal chelation activity than GSH. The results show the potential use of HPH and peptide fractions of defined size for the treatment of oxidative stress-related diseases.

The contributions of individual amino acid residues or groups of amino acids to antioxidant activities of some food protein hydrolysates were investigated using partial least squares (PLS) regression method. PLS models were computed with amino acid composition and 3-z scale descriptors in the X-matrix and antioxidant activities of the samples in the Y-matrix; models were validated by cross-validation and permutation tests. Based on coefficients of the resulting models, it was observed that sulfur-containing (SCAA), acidic and hydrophobic amino acids had strong positive effects on scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2 radicals in addition to ferric reducing antioxidant power. For superoxide radicals, only lysine and leucine showed strong positive contributions while SCAA had strong negative contributions to scavenging by the protein hydrolysates. In contrast, positively-charged amino acids strongly contributed negatively to ferric reducing antioxidant power and scavenging of DPPH and H2O2 radicals. Therefore, food protein hydrolysates containing appropriate amounts of amino acids with strong contribution properties could be potential candidates for use as potent antioxidant agents. We conclude that information presented in this work could support the development of low cost methods that will efficiently generate potent antioxidant peptide mixtures from food proteins without the need for costly peptide purification.

Phytochemicals present in food have shown significant prospects in the treatment and management of a vast array of human diseases. Resveratrol is a stilbene-type aromatic phytoalexin predominantly found in grapes, peanuts, berries, turmeric, and other food products. Resveratrol has been reported to exhibit several physiological activities including anticancer and anti-inflammatory activities in vitro and in experimental animal models, as well as in humans. Anticancer activity of this compound is mainly due to induction of apoptosis via several pathways, as well as alteration of gene expressions, all leading to a decrease in tumor initiation, promotion, and progression. Resveratrol exhibits anti-inflammatory activity through modulation of enzymes and pathways that produce mediators of inflammation and also induction of programmed cell death in activated immune cells. Resveratrol has been shown to produce no adverse effects, even when consumed at high concentrations. Hence, resveratrol possesses good potential to be used as an adjunctive or alternative therapy for cancer and inflammatory diseases.

The aim of this study was to determine the antihypertensive effects of enzymatic hemp seed protein hydrolysate (HPH) and its peptide fractions. Hemp seed protein isolate was digested by the sequential action of pepsin and pancreatin to mimic gastrointestinal digestion in human beings. The resultant HPH was separated by membrane ultrafiltration into peptide fractions with different sizes (\1 and 1-3 kDa). The HPH led to significantly higher (P \ 0.05) in vitro inhibition of the activities of angiotensin I-converting enzyme (ACE) and renin, the two main enzymes involved in abnormal blood pressure elevation (hypertension). Kinetic studies showed that HPH and peptide fractions inhibited renin and ACE activities in a mixed-type pattern, indicating binding to areas other than the active site. Oral administration of HPH (200 mg/kg body weight) to spontaneously hypertensive rats led to significant reductions (P \ 0.05) in systolic blood pressure (SBP) that reached a maximum of -30 mmHg after 8 h. In contrast, the hypotensive effects of peptide fractions (\1 and 1-3 kDa) had a maximum value of about -15 mmHg after 6-8 h post oral administration. The results suggest a synergistic antihypertensive effect of the peptides present within HPH; this effect was reduced significantly (P \ 0.05) upon separation into peptide fractions.

Various kinds of vesicles have been produced from plant, animal and inorganic materials for use as delivery vehicles especially in functional food formulation. However, major drawbacks associated with most of them include issues with sustainability, safety, biocompatibility, biorecognition, stability, bioavailability, bioadhesion, generation of reactive species, inefficient encapsulation and protection, and inability to release the bioactive compounds at target regions of the gastrointestinal tract. The use of vesicles innately formed in plant and animal cells as delivery agents would potentially solve most problems associated with the existing nanodelivery systems. Underutilized vesicles, known as exosomes, exist in plant and animal cells, where they play roles in cell communication and nutrient delivery. To date, exosomes have proven to be stable, biocompatible and able to withstand the activity of digestive enzymes until they reach their target locations. However, there is a need to explore better ways of inducing exosome production, to elucidate their physiological roles, and understand their biogenesis in plants, to discover sustainable methods of isolation of high yields of the vesicles. There is also a need to clarify the digestibility and interaction of the exosomes with blood and gastrointestinal fluids. This review highlights the isolation techniques and delivery potential of exosomes, and equally presents research gaps for enhancing the use of the natural vesicles for delivery purposes.