Effect of Opuntia humifusa supplementation and acute exercise on insulin sensitivity and associations with PPAR-γ and PGC-1α protein expression in skeletal muscle of rats

Beneficial Effects of Opuntia humifusa (Korean Cheonnyuncho) on Human Health Based on Antioxidant Properties: Systematic Review and Meta-Analysis

In this study, a systematic review and meta-analysis are conducted to evaluate the medical applications of Opuntia humifusa (OH). A total of 171 articles are peer-reviewed; however, only 15 individual studies were included after the manual screening to eliminate unnecessary studies. A comparative standardized means difference (SMD) between the OH and control groups is used as a parameter to demonstrate the beneficial effects of OH for skin aging, cancer, and diabetes treatments based on its antioxidant activities. The OH treatment exhibits positive results in improving collagen synthesis and demonstrates that it is nontoxic to normal human cells without analytical heterogeneity (SMD = 1.18 [0.11, 2.26] and I² = 0%). Moreover, the results confirm the effectiveness of OH treatment on downregulatory cancers in terms of decreased cancer cell proliferation and tumor weight and increased numbers of cancer cells in the apoptosis phase (pooled SMD = -1.17 [-1.72, -0.62]). However, this comparison does not yield a statistically significant result (I² = 69%). Additionally, the OH treatment is found to reduce the symptoms of diabetes in diabetic rats, particularly by lowering glucose and triglyceride levels and increasing high-density lipoprotein cholesterol levels. This study suggests that OH extracts are helpful for the prevention of human diseases and might be potential candidates for future medicines.

Opuntia humifusa modulates morphological changes characteristic of asthma via IL-4 and IL-13 in an asthma murine model

Asthma is a chronic pulmonary disease that affects an estimated 235 million people worldwide, but asthma drugs have many adverse effects. Opuntia humifusa (eastern prickly pear) has been used as a food and traditional medicine worldwide; however, its anti-asthmatic effects have not been reported. We evaluated O. humifusa as a potential therapeutic or preventive component of anti-asthmatic drugs. We divided ovalbumin-sensitized mice into the following groups: normal control, asthma-induced control, dexamethasone-treated group (positive control), 50 mg/kg O. humifusa-treated group, 100 mg/kg O. humifusa-treated group, and 500 mg/kg O. humifusa-treated group. Levels of Th1/Th2/Th17-related cytokines were evaluated using RT-PCR, ELISA, and immunohistochemistry. O. humifusa dose-dependently suppressed the morphological changes typically observed in asthma, such as goblet cell hyperplasia, inflammatory cell infiltration, mucous hypersecretion, and relative basement membrane thickening in the respiratory system. These results may be attributable to regulation of Th1-/Th2-/Th17-related factors, especially interleukin (IL)-4 and IL-13. We conclude that O. humifusa is a potential anti-asthmatic functional food.

Abbreviations: O. humifusa: Opuntia humifusa; Th: helper T; RT-PCR: real-time polymerase chain reaction; ELISA: enzyme-linked immunosorbent assay; IL: interleukin; WHO: World Health Organization; IFN-γ: interferon gamma; TNF-α: tumor necrosis factor-alpha; IgE: immunoglobulin E; CD: cluster of differentiation; OVA: ovalbumin; DEX: dexamethasone; BALF: bronchoalveolar fluid; H&E: hematoxylin and eosin; PAS: periodic acid-schiff; PBS: phosphate-buffered saline; BM: basement membrane; cDNA: complementary deoxyribonucleic acid; RNA: ribo nucleic acid; RIPA: radioimmunoprecipitation assay; IHC: immunohistochemistry; HPLC: high-performance liquid chromatography; SD: standard deviation; WBC: white blood cells; APCs: antigen-presenting cells

Food Ingredients That Inhibit Cholesterol Absorption

Cholesterol is a vital component of the human body. It stabilizes cell membranes and is the precursor of bile acids, vitamin D and steroid hormones. However, cholesterol accumulation in the bloodstream (hypercholesterolemia) can cause atherosclerotic plaques within artery walls, leading to heart attacks and strokes. The efficiency of cholesterol absorption in the small intestine is of great interest because human and animal studies have linked cholesterol absorption with plasma concentration of total and low density lipoprotein cholesterol. Cholesterol absorption is highly regulated and influenced by particular compounds in the food supply. Therefore, it is desirable to learn more about natural food components that inhibit cholesterol absorption so that food ingredients and dietary supplements can be developed for consumers who wish to manage their plasma cholesterol levels by non-pharmacological means. Food components thus far identified as inhibitors of cholesterol absorption include phytosterols, soluble fibers, phospholipids, and stearic acid.

Opuntia spp.: Characterization and Benefits in Chronic Diseases

Opuntia species have been used for centuries as food resources and in traditional folk medicine for their nutritional properties and their benefit in chronic diseases, particularly diabetes, obesity, cardiovascular diseases, and cancer. These plants are largely distributed in America, Africa, and the Mediterranean basin. Opuntia spp. have great economic potential because they grow in arid and desert areas, and O. ficus-indica, the domesticated O. species, is used as a nutritional and pharmaceutical agent in various dietary and value-added products. Though differences in the phytochemical composition exist between wild and domesticated (O. ficus-indica) Opuntia spp., all Opuntia vegetatives (pear, roots, cladodes, seeds, and juice) exhibit beneficial properties mainly resulting from their high content in antioxidants (flavonoids, ascorbate), pigments (carotenoids, betalains), and phenolic acids. Other phytochemical components (biopeptides, soluble fibers) have been characterized and contribute to the medicinal properties of Opuntia spp. The biological properties of Opuntia spp. have been investigated on cellular and animal models and in clinical trials in humans, allowing characterization and clarification of the protective effect of Opuntia-enriched diets in chronic diseases. This review is an update on the phytochemical composition and biological properties of Opuntia spp. and their potential interest in medicine.

PGC-1α, glucose metabolism and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a chronic disease characterized by glucose metabolic disturbance. A number of transcription factors and coactivators are involved in this process. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is an important transcription coactivator regulating cellular energy metabolism. Accumulating evidence has indicated that PGC-1α is involved in the regulation of T2DM. Therefore, a better understanding of the roles of PGC-1α may shed light on more efficient therapeutic strategies. Here, we review the most recent progress on PGC-1α and discuss its regulatory network in major glucose metabolic tissues such as the liver, skeletal muscle, pancreas and kidney. The significant associations between PGC-1α polymorphisms and T2DM are also discussed in this review.

Conjugated linoleic acid supplementation enhances insulin sensitivity and peroxisome proliferator-activated receptor gamma and glucose transporter type 4 protein expression in the skeletal muscles of rats during endurance exercise

OBJECTIVES

This study examined whether conjugated linoleic acid (CLA) supplementation affects insulin sensitivity and peroxisome proliferator-activated receptor gamma (PPAR-γ) and glucose transporter type 4 (GLUT-4) protein expressions in the skeletal muscles of rats during endurance exercise.

MATERIALS AND METHODS

Sprague-Dawley male rats were randomly divided into HS (high-fat diet (HFD) sedentary group, n = 8), CS (1.0% CLA supplemented HFD sedentary group, n = 8), and CE (1.0% CLA supplemented HFD exercise group, n = 8). The rats in the CE swam for 60 min a day, 5 days a week for 8 weeks.

RESULTS

The serum glucose and insulin contents and homeostasis model assessment of insulin resistance (HOMA-IR) value of the CS and CE were significantly decreased compared to those of the HS. The PPAR-γ protein expressions in the soleus muscle (SOM) and extensor digitorum longus muscle (EDL) were significantly higher in the CE than in the HS. In addition, the PPAR-γ protein expression in the SOM of the CS was significantly higher than that in the HS. On the other hand, the GLUT-4 protein expression of the SOM in the CE was significantly higher compared to that in the HS. However, there was no significant difference in GLUT-4 protein expression in the EDL among the groups.

CONCLUSION

CLA supplementation with/without endurance exercise has role in improvement of insulin sensitivity. Moreover, when CLA supplementation was accompanied by endurance exercise, the PPAR-γ protein expression in SOM and EDL and the GLUT-4 protein expression in SOM were enhanced compared with the control group.