Gastrointestinal digestion of food proteins: Anticancer, antihypertensive, anti-obesity, and immunomodulatory mechanisms of the derived peptides.

Food proteins and their peptides play a significant role in the important biological processes and physiological functions of the body. The peptides show diverse biological benefits ranging from anticancer to antihypertensive, anti-obesity, and immunomodulatory, among others. In this review, an overview of food protein digestion in the gastrointestinal tract and the mechanisms involved was presented. As some proteins remain resistant and undigested, the multifarious factors (e.g. protein type and structure, microbial composition, pH levels and redox potential, host factors, etc.) affecting their colonic fermentation, the derived peptides, and amino acids that evade intestinal digestion are thus considered. The section that follows focuses on the mechanisms of the peptides with anticancer, antihypertensive, anti-obesity, and immunomodulatory effects. As further considerations were made, it is concluded that clinical studies targeting a clear understanding of the gastrointestinal stability, bioavailability, and safety of food-based peptides are still warranted.

Antidiabetic and antioxidant activities of Mitragyna speciosa (kratom) leaf extract in type 2 diabetic rats.

Mitragyna speciosa is a medicinal plant with a reputation for treating pains, diabetes as well as increasing energy and sexual desires. However, there is no scientific evidence to validate the antidiabetic effect of M. speciosa. This study investigated the antidiabetic effects of M. speciosa (Krat) ethanolic extract on fructose and streptozocin (STZ)-induced type 2 diabetic rats. In vitro antioxidant and antidiabetic effects were evaluated using DPPH, ABST, FRAP and α-glucosidase inhibitory assays. Rats with fructose/STZ induced T2D were treated with Krat (100 and 400 mg/kg) or metformin (200 mg/kg) for 5 weeks via oral gavage. Krat showed good antioxidant activity and also displayed potent α-glucosidase inhibitory activity. Administration of Krat to the diabetic rats significantly improved body weight gain, restored alterations in blood glucose level, glucose tolerance, dyslipidemia (increased cholesterol, triglycerides, low-density lipoprotein-cholesterol and reduced high-density lipoprotein), hepatorenal biomarkers alterations (alanine transaminase, aspartate transaminase, alanine phosphatase, creatinine and blood urea nitrogen) and oxidative stress indices (superoxide dismutase, glutathione and malondialdehyde)in the treated diabetic rats. Furthermore, Krat also restored pancreatic histological and increased immunohistochemical aberrations in the diabetic rats. These results for the first time demonstrated the antidiabetic and antihyperlipidemic potentials of M. speciosa, thus providing scientific reinforcement for the traditional use of the plant in the treatment of diabetes.

Dehydrozingerone Alleviates Hyperalgesia, Oxidative Stress and Inflammatory Factors in Complete Freund's Adjuvant-Induced Arthritic Rats.

Purpose: Rheumatoid arthritis (RA) is a chronic autoimmune disease with severe inflammatory responses. Dehydrozingerone (DHZ) is a potent bioactive compound found in the rhizomes of Zingiber officinale, and it has been reported as an excellent anti-inflammatory and antioxidant agent. This study evaluated the anti-arthritic effects of DHZ in complete Freund's adjuvant (CFA)-induced arthritis. Methods: CFA administered rats were intragastrically treated with DHZ (100 mg/kg) for 28 days, and arthritis severity was assessed via body weight, arthritic score, paw edema and hyperalgesia. Serum inflammation biomarkers, oxidative stress markers, inflammatory cytokines and liver function enzymes were evaluated. Results: The results indicated that DHZ significantly ameliorated arthritis severity as shown by reduced arthritic score, thymus and spleen indexes, paw circumference, paw withdrawal threshold and latency as well as increased body weight gain. Furthermore, DHZ treatment persuasively reduced serum levels of alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT), rheumatoid factor (RF), C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin-1ß and 6 (IL-1ß and IL-6), malondialdehyde (MDA), vascular endothelial growth factor (VEGF) and transforming growth factor ß (TGF-ß). In addition, DHZ observably increased serum superoxide dismutase (SOD) and glutathione (GSH) levels in treated rats. Conclusion: These findings suggest that DHZ possesses anti-RA effect properties via modulating the inflammatory responses and oxidative stress.

Ameliorative potentials of the ethanolic extract from Lycium chinense leaf extract against diabetic cardiomyopathy. Insight into oxido-inflammatory and apoptosis modulation.

The prevalence of cardiovascular complications in diabetes has become one of the major cause of diabetes related morbidity/mortality. The onset and progression of diabetic cardiomyopathy (DCM) has been majorly linked to lipid alterations, oxidative stress, inflammation and apoptosis. This present study investigated the cardioprotective role of Lycium chinense leaf extract (LCME) in fructose/streptozotocin induced diabetic rats. Diabetic animals were orally gavaged with LCME (100 and 400 mg/kg) for five weeks. The results indicated that diabetic rats showed increased blood glucose concentration, serum cardiac function markers (troponin T, creatine kinase-MB, aspartate aminotransferase and lactate dehydrogenase) and lipid profile (triglycerides and cholesterol). In addition, the cardiac tissues of diabetic rats showed increased levels of nuclear factor-κB (NF-κB), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL 1ß), interleukin 6 (IL-6), caspase-3 and malondialdehyde as well as significantly reduced activities of catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase. LCME significantly ameliorated hyperglycemia and markedly decreased serum concentrations of troponin T, creatine kinase-MB, aspartate aminotransferase and lactate dehydrogenase, triglycerides and cholesterol. Furthermore, LCME notably suppressed cardiac oxido-inflammatory mediators and boosted cardiac antioxidant defense. Histopathologically, LCME restored cardiac structural alterations and also suppressed the immunohistochemical expression of collagen IV, smooth muscle alpha-actin (α-SMA) and p53, while Bcl2 expression was significantly increased. In conclusion, our result indicated that LCME protected against diabetic cardiomyopathy suppressing oxidative stress, inflammation, apoptosis and fibrosis.

Cardiorenal Protective Effect of Costunolide against Doxorubicin-Induced Toxicity in Rats by Modulating Oxidative Stress, Inflammation and Apoptosis.

Doxorubicin (DXB) is one of the most commonly used anticancer agents for treating solid and hematological malignancies; however, DXB-induced cardiorenal toxicity presents a limiting factor to its clinical usefulness in cancer patients. Costunolide (COST) is a naturally occurring sesquiterpene lactone with excellent anti-inflammatory, antioxidant and antiapoptotic properties. This study evaluated the effect of COST on DXB-induced cardiorenal toxicity in rats. Rats were orally treated with COST for 4 weeks and received weekly 5 mg/kg doses of DXB for three weeks. Cardiorenal biochemical biomarkers, lipid profile, oxidative stress, inflammatory cytokines, histological and immunohistochemical analyses were evaluated. DXB-treated rats displayed significantly increased levels of lipid profiles, markers of cardiorenal dysfunction (aspartate aminotransferase, creatine kinase, lactate dehydrogenase, troponin T, blood urea nitrogen, uric acid and creatinine). In addition, DXB markedly upregulated cardiorenal malondialdehyde, tumor necrosis factor-α, interleukin-1ß, interleukin-6 levels and decreased glutathione, superoxide dismutase and catalase activities. COST treatment significantly attenuated the aforementioned alterations induced by DXB. Furthermore, histopathological and immunohistochemical analyses revealed that COST ameliorated the histopathological features and reduced p53 and myeloperoxidase expression in the treated rats. These results suggest that COST exhibits cardiorenal protective effects against DXB-induced injury presumably via suppression of oxidative stress, inflammation and apoptosis.

Anti-Inflammatory and Antinociceptive Effects of Boesenbergia rotunda Polyphenol Extract in Diabetic Peripheral Neuropathic Rats.

Introduction: Diabetic peripheral neuropathy (DPN) is still one of the most prevailing complication of diabetes and it affects a huge diabetic population. Boesenbergia rotunda is a ginger species that has both culinary and medicinal applications. Recent studies have revealed that B. rotunda has potential applications in diabetes, pain and inflammatory related disorders. As such this study investigated the potential of B. rotunda extract (EBR) in attenuating DPN in rats. Methods: DPN was induced in male Sprague Dawley rats using a combination of 30% fructose solution and streptozotocin (40 mg/kg). Afterwards diabetic rats were treated with EBR (100 and 400 mg/kg) for 5 weeks. DPN was assessed using thermal hyperalgesia, cold and mechanical allodynia and rotarod test, while nociceptive responses were assessed by formalin and acetic acid test. In addition, serum proinflammatory cytokine levels were determined using ELISA kits. Results: EBR displayed hypoglycemic effect by significantly reducing the blood glucose concentration of treated diabetic rats, while simultaneously alleviating the reduced body weight. Furthermore, EBR markedly alleviated thermal hyperalgesia, cold and mechanical allodynic responses as well as ameliorated motor coordination in the treated diabetic rats. In addition, EBR significantly reduced nociceptive responses in the formalin and acetic acid test, as well as decreased serum levels of proinflammatory cytokines (TNF-α and IL-1ß). Conclusion: The results suggested that EBR exerted anti-inflammatory and anti-nociceptive effects, thus alleviating diabetic painful neuropathy.