Effects of mulberry leaf on experimental hyperlipidemia rats induced by high-fat diet

The palliative effect of mulberry leaf and olive leaf ethanolic extracts on hepatic CYP2E1 and caspase-3 immunoexpression and oxidative damage induced by paracetamol in male rats

This study investigated the possible protective role of mulberry leaf (MLE) and olive leaf (OLE) ethanolic extracts against paracetamol (PTL)-induced liver injury in rats compared to silymarin as a reference drug. Initially, MLE and OLE were characterized using gas chromatography-mass spectrometry (GC/MS). Then, forty male Sprague Dawley rats were divided into five groups: the negative control group orally received distilled water for 35 days, the PTL-treated group (PTG) received 500 mg PTL/kg b. wt. for 7 days, the MLE-treated group (MLTG) received 400 mg MLE/kg b. wt., the OLE-treated group (OLTG) received 400 mg OLE/kg b. wt., and the silymarin-treated group (STG) received 100 mg silymarin/kg b. wt. The last three groups received the treatment for 28 days, then PTL for 7 days. The GC-MS characterization revealed that MLE comprised 19 constituents dominated by ethyl linoleate, phytol, hexadecanoic acid, ethyl ester, and squalene. Moreover, OLE comprised 30 components, and the major components were 11-eicosenoic acid, oleic acid, phytol, and à-tetralone. MLE and OLE significantly corrected the PTL-induced normocytic normochromic anemia, leukocytosis, hypercholesterolemia, and hypoproteinemia. Moreover, the MLE and OLE pretreatment considerably suppressed the PTL-induced increment in serum levels of hepatic enzymes, including alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase. Furthermore, the PTL-induced depletion in antioxidant enzymes, including glutathione peroxidase, superoxide dismutase, and catalase, and the rise in hepatic malondialdehyde content were significantly reversed by the MLE and OLE pretreatment. Besides, MLE and OLE pretreatment significantly protected the hepatic tissue against PTL-induced DNA damage, pathological perturbations, and increased caspase 3 and CYP2E1 immunoexpression. Of note, OLTG showed better enhancement of most indices rather than MLTG. Conclusively, these findings imply that OLE, with its antioxidant and antiapoptotic capabilities, is superior to MLE in protecting against PTL-induced liver injury.

The PPARα/CYP4A14 bile acid pathway is associated with lipid metabolism disorders caused by low birth weight with high-fat diet

Purpose

To investigate possible mechanisms underlying the greater susceptibility of lipid metabolism disorders in low birth weight (LBW) mice fed with high-fat diets (HFDs).

Methods

LBW mice model was established by using the pregnancy malnutrition method. Male pups were selected from LBW and normal-birth weight (NBW) offspring at random. After 3 weeks of weaning, all offspring mice were fed with HFD. Serum triglycerides (TGs), cholesterol (TC), low density lipoprotein (LDL-C), total bile acid (TAB), non-esterified fatty acid (NEFA), and mice fecal bile acid profiles were measured. Lipid deposition in liver sections was visualized by Oil Red O staining. The weight ratio of liver, muscle, and adiposity was calculated. Tandem mass tag (TMT) combined with LC-MS/MS was used to determine the differentially expressed proteins (DEPs) of liver tissue in two groups. Bioinformatics was used for further analysis of DEPs to screen key target proteins, and then Western Blot (WB) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were performed to validate the expressions of DEPs.

Results

LBW mice fed with HFD showed more severe lipid metabolism disorders in the childhood. In contrast to the NBW group, the serum bile acids and fecal ω-muricholic acid (ω-MCA) levels in the LBW group were significantly lower. LC-MS/MS analysis showed that downregulated proteins were associated with lipid metabolism, and further analysis found that these proteins are mainly concentrated in peroxisome proliferation-activated receptor (PPAR) and primary bile acid synthesis signaling pathways and are involved in cellular processes and metabolic processes through binding and catalytic functions. Bioinformatics analysis indicated that the level of Cytochrome P450 Family 46 Subfamily A Member 1 (CYP46A1), PPARα, key factors of cholesterol metabolism and bile acid synthesis, as well as downstream molecules Cytochrome P450 Family 4 Subfamily A Member 14 (CYP4A14), and Acyl-Coenzyme A Oxidase 2 (ACOX2) are markedly different in the liver of LBW individuals fed with HFD, and confirmed by WB and RT-qPCR.

Conclusion

LBW mice are more prone to dyslipidemia probably due to downregulated bile acid metabolism-related PPARα/CYP4A14 pathway, resulting in insufficient metabolism of cholesterol to bile acids, which, in turn, leads to elevated blood cholesterol.

The Effect of Hot-Melt Extrusion of Mulberry Leaf on the Number of Active Compounds and Antioxidant Activity

The aim of this study is to compare the functions of the physiologically active compounds of three types of mulberry leaf by cultivar, and to confirm the changes using hot-melt extrusion (HME-ML). The active components of mulberry leaf were analyzed using the HPLC system, and total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity were measured. Among the three varieties, the highest contents of rutin and isoquercetin were detected in Cheongil, of TPC in Cheongol, and of TFC in Cheongil. It was confirmed that this bio-accessibility was increased in HME-ML compared with the control. The DPPH radical scavenging activity of Cheongol showed greater antioxidant properties, and HME showed improvement in the antioxidant properties of all mulberry leaves. These results suggest that the application of HME technology can improve the biological activities of mulberry leaf.

Medicinal and edible plants in the treatment of dyslipidemia: advances and prospects

Dyslipidemia is an independent risk factor of cardiovascular diseases (CVDs), which lead to the high mortality, disability, and medical expenses in the worldwide. Based on the previous researches, the improvement of dyslipidemia could efficiently prevent the occurrence and progress of cardiovascular diseases. Medicinal and edible plants (MEPs) are the characteristics of Chinese medicine, and could be employed for the disease treatment and health care mostly due to their homology of medicine and food. Compared to the lipid-lowering drugs with many adverse effects, such as rhabdomyolysis and impaired liver function, MEPs exhibit the great potential in the treatment of dyslipidemia with high efficiency, good tolerance and commercial value. In this review, we would like to introduce 20 kinds of MEPs with lipid-lowering effect in the following aspects, including the source, function, active component, target and underlying mechanism, which may provide inspiration for the development of new prescription, functional food and complementary therapy for dyslipidemia.

The Hypolipidemic and Antioxidant Activity of Wheat Germ and Wheat Germ Protein in High-Fat Diet-Induced Rats

Background: So far, no articles have discussed the hypolipidemic effect of wheat germ protein in in vivo experiments. Objective: In this study, we investigated the effects of wheat germ protein (WGP, 300 mg/kg/day) and wheat germ (WG, 300 mg/kg/day) on cholesterol metabolism, antioxidant activities, and serum and hepatic lipids in rats fed a high-fat diet through gavage. Methodology: We used 4-week-old male Wistar 20 rats in our animal experiment. Biochemical indicators of fecal, serum and liver were tested by kits or chemical methods. We also conducted the cholesterol micellar solubility experiment in vitro. Results: After 28 days of treatment, our results showed that WGP significantly reduced the serum levels of total cholesterol (p < 0.05) and nonhigh-density lipoprotein cholesterol (p < 0.05), improved the enzymatic activities of cholesterol 7-α hydroxylase (p < 0.01) and low-density lipoprotein receptor (p < 0.01) and increased bile acid excretion in feces (p < 0.05). Conclusion: WG did not significantly increase bile acid excretion in feces or decrease serum levels of total cholesterol. Moreover, WGP and WG both presented significant antioxidant activity in vivo (p < 0.05) and caused a significant reduction in cholesterol micellar solubility in vitro (p < 0.001). Therefore, WGP may effectively prevent hyperlipidemia and its complications as WGP treatment enhanced antioxidant activity, decreased the concentration of serum lipids and improved the activity of enzymes involved in cholesterol metabolism.

Network pharmacology approach to evaluate the therapeutic effects of mulberry leaf components for obesity

Obesity is a chronic condition that has become a serious public health challenge globally due to the association with a high incidence of complications. Mulberry leaf is one of the most commonly used medicinal and herbal medicines that has been reported to ameliorate obesity and hyperlipidemia. However, the mechanism remains unclear. In the present study, a network pharmacology approach was used to explore the potential mechanism underlying the effects of mulberry leaf extract on obesity. First, the potential targets of mulberry leaf and obesity were predicted using SwissTargetPrediction, Online Mendelian Inheritance in Man, GeneCards and Comparative Toxicogenomics Database databases, which were then used to construct the protein-protein interaction networks. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzes were performed using R version 3.6.3. Finally, results of this network analysis were verified by using the mulberry leaf extract to treat high-fat diet-induced obese mice. In total, 24 target genes associated with obesity that could potentially be affected by mulberry leaf treatment were predicted by network pharmacology, using which top seven related pathways were determined by KEGG enrichment analysis. Triglyceride (TG) and total cholesterol (TC) levels in mice serum were detected using TG and TC assay kits. Hepatic fat accumulation was detected by H&E staining whereas liver lipid droplets were detected by Oil red O staining in mice tissues. The expression of IL-1β, NF-κB inhibitor α, inducible nitric oxide synthase, AMP-activated protein kinase (AMPK), sterol regulatory element-binding proteins and fatty acid synthase in the visceral white adipose tissues of mice was analyzed by western blotting. The expression of TNF-α, peroxisome proliferator activated receptor (PPAR)D, PPARG, fatty acid amide hydrolase (FAAH) and hydroxysteroid 11-β dehydrogenase 1 (HSD11B1) in the visceral white adipose tissues of mice was detected by reverse transcription-quantitative PCR. Mulberry leaf extract was found to reduce fat accumulation and hepatic lipid droplet formation. Mulberry leaf also alleviated inflammation and lipogenesis whilst promoting lipid catabolism and fatty acid oxidation by promoting the AMPK signaling pathway. The possible anti-obesity effects of mulberry leaf on the mice may be due to the downregulation of TNF-α, PPARD and PPARG and the upregulation of FAAH and HSD11B1. These results were consistent with the GO enrichment analysis and suggested that mulberry leaf may regulate lipid metabolism and catabolism, fatty acid metabolism and biosynthesis and the inflammatory response to reduce obesity.

Alleviative effects of total flavones of Glycyrrhiza uralensis Fisch on oxidative stress and lipid metabolism disorder induced by high-fat diet in intestines of Tilapia (Oreochromis niloticus)

Total flavones of Glycyrrhiza uralensis Fisch (GTF) are main components of Glycyrrhiza uralensis Fisch, which have anti-oxidation and lipid-lowering effects. However, its protective effects on the intestinal tissue of tilapia (Oreochromis niloticus) are unknown. The aims of the study were to evaluate the protective effects of GTF on the intestinal tissue of tilapia after high-fat diet (HFD) feeding. Tilapia (initial weight 30 ± 1 g) received diets containing four doses of GTF (0.05, 0.1, 0.5, and 1.0 g/kg diet) for 90 days. The intestinal tissues were collected to determine biochemical parameter, gene expression and protein level. The results showed that the HFD reduced antioxidant indexes and increased the fat level, lipid oxidation products in the intestinal tissue relative to the control. Adding GTF to the HFD resulted in an increase of antioxidant indexes, fat level and lipid oxidation products decreased after 60, 90 days. In the HFD group, mRNA level of fatty acid transport protein 1 (FATP1) was increased at 60 day and then decreased at 90 day. The mRNA levels of fatty acid binding protein 1 (FABP1) and sterol regulatory element binding protein 1c (SREBP 1c) were significantly increased at 60 or 90 day after HFD feeding. The mRNA levels of acetate coenzyme A carboxylase (ACCA) peroxisome proliferator-activated receptor γ (PPAR-γ) and PPAR-α were decreased significantly at 30, 60 and/or 90 days after HFD feeding. Western blotting results also showed that nuclear factor (NF)-κβ C-Rel (NF-κβ C-Rel) and mitogen-activated protein kinase 8 (MAPK8) protein expression in intestinal tissue increased after consumption of the HFD. However, adding GTF to the HFD reversed the changes of genes related to fatty acid synthesis and metabolism, and the level of NF-κβ c-Rel and MAPK8 at different degrees. Overall, these results indicated that GTF promoted decomposition and metabolism of fatty acids in intestinal tissue, alleviated oxidative stress damage caused by the HFD, and had certain protective effects on the intestinal tissue of tilapia.

High hydrostatic pressure extract of mulberry leaves ameliorates hypercholesterolemia via modulating hepatic microRNA-33 expression and AMPK activity in high cholesterol diet fed rats

Background

Mulberry leaf (Morus alba L.) contains multiple bioactive ingredients and has been used in the treatment of obesity, diabetes, inflammation, and atherosclerosis. High hydrostatic pressure (HHP) processing has been developed for the extraction of bioactive compounds from plants. However, the hypocholesterolemic effect of the HHP extract from mulberry leaves and its underlying mechanism have never been investigated.

Objective

The specific aim of the present study was to investigate the hypocholesterolemic property of a novel extract obtained from mulberry leaves under HHP in rats.

Design

Sprague–Dawley rats were divided into four groups and fed either a normal diet (NOR), a high cholesterol diet containing 1% cholesterol and 0.5% cholic acid (HC), an HC diet containing 0.5% mulberry leaf extract (ML), or a 1% mulberry leaf extract (MH) for 4 weeks.

Results

High hydrostatic pressure extract of mulberry leaves significantly reduced the HC-increased serum levels of triglyceride (TG), cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and hepatic contents of TG and TC. The HHP extraction from mulberry leaves also increased the HC-decreased fecal TC and bile acid levels without changing body weight, food intake, liver weight, and serum activities of alanine transaminase (ALT) and aspartate transaminase (AST) (P < 0.05). The mulberry leaf extract significantly enhanced the expression of hepatic genes such as cholesterol 7 alpha-hydroxylase (CYP7A1), liver X receptor alpha (LXRα), and ATP-binding cassette transporters, ABCG5/ABCG8, involved in hepatic bile acid synthesis and cholesterol efflux (P < 0.05). In addition, the HHP extraction of mulberry leaves significantly suppressed hepatic microRNA(miR)-33 expression and increased adenosine monophosphate-activated protein kinase (AMPK) activity.

Conclusion

These results suggest that the HHP extract of mulberry leaves lowers serum cholesterol levels by partially increasing hepatic bile acid synthesis and fecal cholesterol excretion through the modulation of miR-33 expression and AMPK activation in the liver.

Cis- and Trans-Palmitoleic Acid Isomers Regulate Cholesterol Metabolism in Different Ways

Hypercholesterolemia is a preventable risk factor for atherosclerosis and cardiovascular disease. However, the mechanisms whereby cis-palmitoleic acid (cPOA) and trans-palmitoleic acid (tPOA) promote cholesterol homeostasis and ameliorate hypercholesterolemia remain elusive. To investigate the effects of cPOA and tPOA on cholesterol metabolism and its mechanisms, we induced hypercholesterolemia in mice using a high-fat diet and then intragastrically administered cPOA or tPOA once daily for 4 weeks. tPOA administration reduced serum cholesterol, low-density lipoprotein, high-density lipoprotein, and hepatic free cholesterol and total bile acids (TBAs). Conversely, cPOA had no effect on these parameters except for TBAs. Histological examination of the liver, however, revealed that cPOA ameliorated hepatic steatosis more effectively than tPOA. tPOA significantly reduced the expression of 3-hydroxy-3-methyl glutaryl coenzyme reductase (HMGCR), LXRα, and intestinal Niemann-Pick C1-Like 1 (NPC1L1) and increased cholesterol 7-alpha hydroxylase (CYP7A1) in the liver, whereas cPOA reduced the expression of HMGCR and CYP7A1 in the liver and had no effect on intestinal NPC1L1. In summary, our results suggest that cPOA and tPOA reduce cholesterol synthesis by decreasing HMGCR levels. Furthermore, tPOA, but not cPOA, inhibited intestinal cholesterol absorption by downregulating NPC1L1. Both high-dose tPOA and cPOA may promote the conversion of cholesterol into bile acids by upregulating CYP7A1. tPOA and cPOA prevent hypercholesterolemia via distinct mechanisms.