Effect of Morus alba leaf extract dose on lipid oxidation, microbiological stability, and sensory evaluation of functional liver pâtés during refrigerated storage

Mulberry (Morus alba L.), and above all the extract from the leaves of this plant, is a natural medicine that has been used in traditional medicine for hundreds of years. Mulberry leaves contains polyphenol compounds: flavonoids, coumarins, numerous phenolic acids, as well as terpenes and steroids. The antioxidant effect of these compounds may be beneficial to the fat fraction of meat products, thereby increasing their functional qualities. The aim of the study was to evaluate the effectiveness of the use of mulberry water leaf extract, as an additive limiting adverse fat changes and affecting the functionality in model liver pâtés. Pork pâtés were prepared by replacing 20% of animal fat with rapeseed oil (RO), and water extract of mulberry leaves was added in the proportion of 0.2%, 0.6% and 1.0%. It has been shown that the addition of mulberry leaf extract delayed the appearance of primary and secondary fat oxidation products. The most effective antioxidant effect during 15-day storage was observed in the sample with the addition of 0.6% and 1.0% water mulberry leaf extract. These samples also showed inhibiting activity against angiotensin-converting enzymes and cholinesterase’s. During storage, the tested pâtés had a high sensory quality with unchanged microbiological quality. Mulberry leaf extract can be an interesting addition to the production of fat meat products, delaying adverse changes in the lipid fraction and increasing the functionality of products.

The impact of the mulberry (Morus nigra L.) leaf extract on the physicochemical properties of poly(vinyl alcohol) blend films

In this work, mulberry (Morus nigra L.) leaf extract was added in poly(vinyl alcohol) (PVA)-based films and its impact on the film’s properties was evaluated. In addition, HCl and glycerol were studied for their use as additives to prepare PVA-based films. The results showed that HCl and glycerol have minimal impacts on the films’ appearance, while mulberry leaf extract imparted green colour to the films produced, mainly due to the presence of green pigments. Moreover, the results suggested that a significant interaction has occurred between the polymer matrix and leaf extract, contributing to a more compact and uniform film morphology. The tensile strengths of the films increased from 21.38 to 28.28 MPa after the addition of mulberry leaf extract. Additionally, the films were tested for their application as food wrapping films. Overall, the results showed that PVA-based films incorporated with mulberry leaf extract have higher capability to preserve the freshness of food when compared to commercial cling wraps from brands such as Diamond and Glad. Appropriate proportions of additives (mulberry leaf extract, HCl and glycerol) used in the formulation of P-GH-M20 films showed improvement in its mechanical properties and food preservation capability.

Mulberry Leaf Extract Alleviates Staphylococcus Aureus-Induced Conjunctivitis in Rabbits via Downregulation of NLRP3 Inflammaome and Upregulation of the Nrf2 System and Suppression of Pro-Inflammatory Cytokines

Mulberry leaves are widely used in traditional Chinese medicine for their antioxidant, anti-inflammatory, antibacterial, antiobesity, antidiabetic, antiatherosclerotic, and anticancer properties. The current study aimed to investigate the effect of mulberry leaf extract (MLE) on Staphylococcus aureus (S. aureus)-induced conjunctivitis (5 × 109 CFU, 0.5 mL/eye) in a rabbit model. Rabbits were treated with MLE (5 mL/kg·d-1 and 10 mL/kg·d-1), 0.9% saline, or pearl bright eye drops (PBE) for 5 days. The results showed that MLE treatment significantly reduced the clinical sign scores of conjunctivitis, alleviated clinical signs, and decreased bacterial load and histological damage in a time- and dose-dependent manner compared to that in the conjunctivitis control group. The antibacterial and anti-inflammatory activities of MLE (10 mL/kg·d-1) were equal to or greater than those of the positive control drug PBE. In addition, MLE significantly decreased the levels of pro-inflammatory cytokines, downregulated the NOD-like receptor leucine-rich pyrin domain-containing protein 3 (NLRP3) inflammasome, and upregulated the nuclear factor erythroid 2-related factor 2 (Nrf2) system. Overall, MLE is effective in alleviating S. aureus-induced conjunctivitis in rabbits and this mechanism is associated with the inhibition of the NLRP3 inflammasome and activation of the Nrf2 system to regulate pro-inflammatory signaling.

Correction to: Mulberry leaf extract improves glycaemic response and insulaemic response to sucrose in healthy subjects: results of a randomized, double blind, placebo‑controlled study

An amendment to this paper has been published and can be accessed via the original article.

Aqueous Mulberry Leaf Extract Ameliorates Alcoholic Liver Injury Associating with Upregulation of Ethanol Metabolism and Suppression of Hepatic Lipogenesis

Excessive alcohol intake is a major cause of chronic liver damage and is highly associated with the development of a spectrum of hepatic disorders, including steatohepatitis, liver cirrhosis, and liver cancer. Thus, we aimed to explore the hepatoprotective effects of an aqueous mulberry leaf extract (AME) on alcoholic fatty liver disorder (AFLD) by using a mouse model fed with excessive ethanol. Compared with the normal diet, the ethanol diet significantly increased the body weight of the mice, while the AME supplement reduced the weight gain caused by the ethanol diet. The ethanol diet also attenuated the activity of alcohol dehydrogenase and antioxidant enzymes but increased lipid peroxidation in the liver, which were reversed by AME supplementation. Additionally, AME supplementation diminished the ethanol diet-induced hepatic leukocyte infiltration and expressions of IL-6 and TNFα. Moreover, AME supplementation also reduced the ethanol-diet-induced lipid accumulation and expression of 1-acylglycerol-3-phosphate acyltransferase, acetyl-CoA carboxylase, low-density lipoprotein receptor, and sterol regulatory element-binding protein-1/2 in the liver. Collectively, AME supplementation improved liver lipid accumulation and proinflammatory response in mice induced by the ethanol diet, which was associated with the upregulation of ethanol-metabolizing enzymes and the downregulation of lipogenesis components.

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.

Mulberry leaf extract improves glycaemic response and insulaemic response to sucrose in healthy subjects: results of a randomized, double blind, placebo-controlled study

Background There are many benefits of maintaining healthy blood glucose levels, and studies have shown that lifestyle changes such as changes to diet can successfully restore normoglycaemia in participants with dysglycaemia. Significant health-related lifestyle changes are often difficult to implement and functional ingredients that can reduce glycaemic and insulaemic responses may help at risk populations. The aim of this study was to investigate whether a mulberry leaf extract could lower the glycaemic and insulinaemic responses to 75 g sucrose in healthy individuals. Methods A double-blind, randomised, placebo-controlled, crossover design trial was conducted by the Oxford Brookes Centre for Nutrition and Health. Thirty-eight participants were recruited into the trial and, after an overnight fast, were given 75 g sucrose + white mulberry leaf extract, or 75 g sucrose alone. Capillary blood samples were collected at 15-min intervals in the first hour and at 30-min intervals over the second hour to determine glucose and plasma insulin levels. Data analysis was conducted using a paired samples T test or a Wilcoxon signed rank test. Results The addition of mulberry leaf extract to sucrose resulted in a significantly lower glycaemic response and insulinaemic response compared to a matched placebo (sucrose alone). The change in blood glucose measurements were significantly lower at 15 min (p < 0.001), 30 min (p < 0.001), 45 min (p = 0.008), and 120 min (p < 0.001) and plasma insulin measurements were significantly lower at 15 min (p < 0.001), 30 min (p < 0.001), 45 min (p < 0.001), 60 min (p = 0.001) and 120 min (p < 0.001). The glucose iAUC (− 42%, p = 0.001), insulin iAUC (− 40%, p < 0.001), peak glucose (− 40.0%, p < 0.001) and peak insulin (− 41%, p < 0.001) from baseline were significantly lower for white mulberry leaf extract compared with the placebo. White mulberry leaf extract was well tolerated and there were no reported adverse events. Conclusions Mulberry leaf extract can be used as part of lifestyle changes that may lead to healthy blood glucose levels. Trial registration: ISRCTN99601810 (23 October 2020, retrospectively registered)