Purple sweet potato color protects against hepatocyte apoptosis through Sirt1 activation in high-fat-diet-treated mice

Anthocyanins: Potential phytochemical candidates for the amelioration of non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is described by too much hepatic fat deposition causing steatosis, which further develops into nonalcoholic steatohepatitis (NASH), defined by necroinflammation and fibrosis, progressing further to hepatic cirrhosis, hepatocellular carcinoma, and liver failure. NAFLD is linked to different aspects of the metabolic syndrome like obesity, insulin resistance, hypertension, and dyslipidemia, and its pathogenesis involves several elements including diet, obesity, disruption of lipid homeostasis, and a high buildup of triglycerides and other lipids in liver cells. It is therefore linked to an increase in the susceptibility to developing diabetes mellitus and cardiovascular diseases. Several interventions exist regarding its management, but the availability of natural sources through diet will be a benefit in dealing with the disorder due to the immensely growing dependence of the population worldwide on natural sources owing to their ability to treat the root cause of the disease. Anthocyanins (ACNs) are naturally occurring polyphenolic pigments that exist in the form of glycosides, which are the glucosides of anthocyanidins and are produced from flavonoids via the phenyl propanoid pathway. To understand their mode of action in NAFLD and their therapeutic potential, the literature on in vitro, in vivo, and clinical trials on naturally occurring ACN-rich sources was exhaustively reviewed. It was concluded that ACNs show their potential in the treatment of NAFLD through their antioxidant properties and their efficacy to control lipid metabolism, glucose homeostasis, transcription factors, and inflammation. This led to the conclusion that ACNs possess efficacy in the amelioration of NAFLD and the various features associated with it. However, additional clinical trials are required to justify the potential of ACNs in NAFLD.

Natural products in non-alcoholic fatty liver disease (NAFLD): Novel lead discovery for drug development

With changing lifestyles, non-alcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease worldwide. A substantial increase in the incidence, mortality, and associated burden of NAFLD-related advanced liver disease is expected. Currently, the initial diagnosis of NAFLD is still based on ultrasound and there is no approved treatment method. Lipid-lowering drugs, vitamin supplementation, and lifestyle improvement treatments are commonly used in clinical practice. However, most lipid-lowering drugs can produce poor patient compliance and specific adverse effects. Therefore, the exploration of bio-diagnostic markers and active lead compounds for the development of innovative drugs is urgently needed. More and more studies have reported the anti-NAFLD effects and mechanisms of natural products (NPs), which have become an important source for new drug development to treat NAFLD due to their high activity and low side effects. At present, berberine and silymarin have been approved by the US FDA to enter clinical phase IV studies, demonstrating the potential of NPs against NAFLD. Studies have found that the regulation of lipid metabolism, insulin resistance, oxidative stress, and inflammation-related pathways may play important roles in the process. With the continuous updating of technical means and scientific theories, in-depth research on the targets and mechanisms of NPs against NAFLD can provide new possibilities to find bio-diagnostic markers and innovative drugs. As we know, FXR agonists, PPARα agonists, and dual CCR2/5 inhibitors are gradually coming on stage for the treatment of NAFLD. Whether NPs can exert anti-NAFLD effects by regulating these targets or some unknown targets remains to be further studied. Therefore, the study reviewed the potential anti-NAFLD NPs and their targets. Some works on the discovery of new targets and the docking of active lead compounds were also discussed. It is hoped that this review can provide some reference values for the development of non-invasive diagnostic markers and new drugs against NAFLD in the clinic.

Inhibitory regulation of purple sweet potato polysaccharide on the hepatotoxicity of tri-(2,3-dibromopropyl) isocyanate

Tri-(2,3-dibromopropyl) isocyanate (TBC), a new emerged persistent organic pollutant, is widely used in fields of flame retardant, textile, rubber and plastic with strong hepatotoxicity. Purple Sweet Potato Polysaccharide (PSPP) has antioxidant and hepatoprotective effects. This study aims to answer the scientific question whether PSPP has a protective effect on TBC induced liver injury. The effect of PSPP on the apoptosis of HepG2 cells was detected by MTT assay, the morphological changes were observed by morphological observation, and the apoptosis rate was determined by flow cytometry. The apoptotic genes were detected by qPCR assay, the relevant protein express was detected by western blot. The correlation between proteins and genes in the apoptosis pathway of HepG2 cells was calculated. To further reveal the apoptosis mechanism of TBC hepatotoxicity in vivo, 19 target genes and 14 apoptotic related proteins of inhibiting apoptosis via death receptor and mitochondria were discussed, all the above results proved that PSPP had protective effect on liver injury induced by TBC. This study not only provided a scientific basis for clarifying the mechanism of TBC hepatotoxicity and the protective effect of PSPP, but also generated the new point and method in terms of the prevention in advance and early intervention of diseases caused by environmental pollution.

Anthocyanin from purple sweet potato attenuates lead-induced reproductive toxicity mediated by JNK signaling pathway in male mice

The present work aimed to explore the protective effect of APSP on Pb-induced reproductive toxicity and possible mechanism. APSP (100 mg/kg) was administered to Pb-intoxicated (0.2% lead acetate) male Kunming mice once daily by oral gavage for 6 weeks. Our results showed that APSP exerted male reproductive protection effects as showed by attenuated Pb-induced testicular injury, improved sperm count and motility, and reduced sperm abnormality rate. APSP also restored Pb-induced decrease in both enzymatic and non-enzymatic antioxidants, and GSH/GSSG ratio, but inhibited lipid peroxidation in serum and testes. Moreover, APSP downregulated Pb-induced Bax mRNA and protein expressions, suppressed activation of caspase-3, upregulated Bcl-2 protein expression, and prevented Pb-induced DNA damage. APSP treatment also interfered with Pb-induced testicular JNK signaling through inhibition of JNK mRNA expression and phosphorylation, resulting in inhibition of c-Jun expression. These effects of APSP were abolished by Pb. In conclusion, APSP represents a potential therapeutic agent for preventing Pb-caused reproductive toxicity, which is attributed to its antioxidant and anti-apoptotic properties, as well as, modulation of JNK signaling pathway.

Immune-Enhancing Effects of a Novel Glucan from Purple Sweet Potato Ipomoea batatas (L.) Lam on RAW264.7 Macrophage Cells via TLR2- and TLR4-Mediated Pathways

PSPP-1 was obtained from purple sweet potato, and the effects of PSPP-1 on the immune modulation on macrophage cells were investigated for the first time. PSPP-1 promoted RAW264.7 proliferation and increased the total cell percentage in DNA synthesis and mitosis phases, and the cell morphology changed in volume and appearance. Additionally, the RAW264.7 immune functions of phagocytic activity and nitric oxide, reactive oxygen species, and cytokine production were improved by PSPP-1. The western blot experiment showed that PSPP-1 could activate toll-like receptor 2 and toll-like receptor 4-mediated pathways, and the expressions of proteins in MyD88-dependent, mitogen-activated protein kinase (MAPK)-signaling, NF-κB-signaling, AP-1 signaling, and TRIF-dependent pathways were improved markedly. Molecular docking and Biolayer Interferometry study further indicated that PSPP-1 could recognize and bind TLR2 and TLR4 by targeting the binding sites with a strong affinity. It suggested that PSPP-1 could enhance immunity via TLR2- and TLR4-mediated pathways, and it could be explored as an immunomodulatory agent.

Sweet Potato Leaf Feeding Decreases Cholesterol, Oxidative Stress and Thrombosis Formation in Syrian Hamsters with a High-Cholesterol Diet

Nutritional strategies to reduce hyperlipidemia and the risk of cardiovascular disease are gaining more public favor and medical professionals’ attention. The authors of this study explored the effect of sweet potato leaf powder (SPLP) feeding on the parameters of plasma lipids, reactive oxygen species, and time to thrombosis formation in Syrian hamsters fed with high-cholesterol diets. The animals were separated into six groups: a feeding control diet, a control diet containing 0.1% cholesterol, a control diet containing 0.2% cholesterol, a control diet containing 0.1% cholesterol plus 2.5% SPLP, a control diet containing 0.1% cholesterol plus 5% SPLP, and a control diet containing 0.2% cholesterol plus 5% SPLP for six weeks. The levels of serum total cholesterol (51% increase), low-density lipoprotein cholesterol (70.6% increase), very-low-density lipoprotein cholesterol (51.3% increase), and the triglyceride and atherogenic index (LDL-C/HDL-C) significantly increased in the high-cholesterol diet groups. Concomitant 5% sweet potato leaf powder ingestion significantly decreased the lipid profiles, with a 20.6% total cholesterol reduction in the 0.1% cholesterol diet groups, a 17.2% reduction in the 0.2% group, a 48.7% LDL reduction in the 0.1% cholesterol group, and a 30.3% reduction in the 0.2% group, with a consequent decrease in the atherogenic index. SPLP feeding was found to be associated with increased fecal sterol contents, with a 188.6% increase in the 0.1% cholesterol-fed group and a 177.3% increase in the 0.2% group. The SPLP-fed groups had depressed ROS levels, elongated FeCl₃-induced times to thrombosis formation, and increased liver superoxide dismutase contents and SREBP-1 protein expression. Sweet potato leaf intake could reduce plasma total cholesterol, LDL, and oxidative stress. We suggest sweet potato leaf intake as a choice of nutritional strategy for hyperlipidemia and cardiovascular disease prevention.

Metabolic Impact of Flavonoids Consumption in Obesity: From Central to Peripheral

The prevention and treatment of obesity is primary based on the follow-up of a healthy lifestyle, which includes a healthy diet with an important presence of bioactive compounds such as polyphenols. For many years, the health benefits of polyphenols have been attributed to their anti-oxidant capacity as free radical scavengers. More recently it has been described that polyphenols activate other cell-signaling pathways that are not related to ROS production but rather involved in metabolic regulation. In this review, we have summarized the current knowledge in this field by focusing on the metabolic effects of flavonoids. Flavonoids are widely distributed in the plant kingdom where they are used for growing and defensing. They are structurally characterized by two benzene rings and a heterocyclic pyrone ring and based on the oxidation and saturation status of the heterocyclic ring flavonoids are grouped in seven different subclasses. The present work is focused on describing the molecular mechanisms underlying the metabolic impact of flavonoids in obesity and obesity-related diseases. We described the effects of each group of flavonoids in liver, white and brown adipose tissue and central nervous system and the metabolic and signaling pathways involved on them.