The Role of Bioactive Peptides in Diabetes and Obesity

Abstract

Bioactive peptides are present in most soy products and eggs and have essential protective functions. Infection is a core feature of innate immunity that affects blood pressure and the glucose level, and ageing can be delayed by killing senescent cells. Food also encrypts bioactive peptides and protein sequences produced through proteolysis or food processing. Unique food protein fragments can improve human health and avoid metabolic diseases, inflammation, hypertension, obesity, and diabetes mellitus. This review focuses on drug targets and fundamental mechanisms of bioactive peptides on metabolic syndromes, namely obesity and type 2 diabetes, to provide new ideas and knowledge on the ability of bioactive peptide to control metabolic syndromes.

Keywords: anti-inflammatory; antimicrobial; antioxidant; antiviral; bioactive peptides; diabetes; obesity.

Figure 1

Bioactive peptides and associated health benefits, where attributed to their physiological activities exerted in vitro and in vivo, these include lowering blood pressure by inhibiting the angiotensin-converting enzyme (ACE); oxidative stress reduction by neutralizing or scavenging free radicals; antimicrobial (targeting binding efficacy towards the pathogen cell wall), anticoagulant, antitumor (targeting cancer cells), and anti-inflammatory (triggering the anti-inflammatory cytokines).

Figure 2

Proposed model of the cross-talks between PPARs and bioactive peptide in obesity. The anti-obesity activity of bioactive peptide by downregulating the expression of the nuclear transcription factor PPARγ.

Figure 3

Mechanism of action of cholesterol-lowering peptides indicates the summary of the hypocholesteromic mechanisms of lupin protein-derived peptides in hepatocytes. Lupin protein represent the cholesterol-lowering effects targeting PCSK9: from clinical evidence to elucidation of the in vitro molecular mechanism using HepG2 cells.

Figure 4

Bioactive peptides exhibit antidiabetic effects for type 2 diabetes mellitus based on inhibition against α- amylase, α-glucosidase, sodium glucose co-transporter-2 inhibitors, plasma-based dipeptidyl peptidase-4 (DPP4) inhibitors (an obesity-independent parameter for glycaemic deregulation in type 2 diabetes patients), and insulin mimetic (which promote the glucose entry into the tissues, whereas the glucose either be converted into energy or stored for later use), respectively.

Figure 5

The schematic diagram indicates the anti-inflammatory activity of bioactive peptides derived from food protein occurs via inhibition of the NF-KB, MAPK, and JAK-STAT pathways. MAPK: mitogen-activated protein kinase; MAP3K: MAPK kinase; NF-κB: nuclear factor-kappa B; TGF-β: transforming growth factor β; TNF-α: tumor necrosis factor α; JAK-STAT: Janus kinase-signal transducer and activator of transcription.

Figure 6

Bioactive peptides, inhibit key enzymes involved in diabetes—DPP IV, α-amylase, and α-glucosidase, which results in the antidiabetic activity mainly by promoting insulin signaling and the AMPK signaling pathway.

Figure 7

Production of bioactive peptides based on the enzymatic hydrolysis (using proteolytic enzymes from either plants or microbes), hydrolysis with digestive enzymes (simulated gastrointestinal digestion), by fermentation using starter cultures, solvent extraction based on the precipitation of the proteins, triggering the overexpression of the peptide based on stress mechanism.

Figure 8

Structural characterization of fish-based bioactive peptides was determined initially by purification through nano-filtration, ultra-filtration, and gel-filtration; the purified peptides were further characterized based on the molecular weight using high-performance liquid chromatography mass spectrometry and the protein sequence was determined using liquid chromatography mass spectrometry.

Figure 9

Protein mixtures can be characterized in terms of their separations by capillary electrophoresis (CE). The detection of peptide in CE is usually based on the ultraviolet (UV) absorbance of the peptide bond at or near 200 nm.

Figure 10

Reversed-phase high-performance liquid chromatography (RP-HPLC) involves the separation of molecules on the basis of hydrophobicity. The separation depends on the hydrophobic binding of the solute molecule from the mobile phase to the immobilized hydrophobic ligands attached to the stationary phase. (1) The resolution achieved under a wide range of chromatographic conditions, even a closely related peptides and structurally quite distinct peptides; (2) selective chromatographic was obtained based on altering the mobile phase characteristics; (3) leads to higher level of peptide recoveries leads to increased productivity; and (4) the reproducibility on the separations were stabile under a wide range of mobile phase conditions.