Pear pomace water extract suppresses hepatic lipid peroxidation and protects against liver damage in rats fed a high fat/cholesterol diet

Exploring the Bioactive Properties and Therapeutic Benefits of Pear Pomace

The fruit juice industry generates a significant amount of waste, with a strong impact on the environment and the economy. Therefore, researchers have been focusing on the characterization of resources considered as food waste. This work provides information about the lipophilic and polar metabolites of pear pomace flours (PPFs) as a tool that can shed more light on the bioactive potential of this residue. Using UPLC-PDA, UPLC-FLR, and GC-MS, the study identified and quantified PPF's polar and non-polar metabolites. Essential, conditional, and non-essential amino acids were found, with asparagine being the most abundant. Isoprenoids, including lutein, zeaxanthin, and carotene isomers, ranged from 10.8 to 22.9 mg/100 g dw. Total flavonoids and phenolic compounds were 520.5-636.4 mg/100 g dw and 536.9-660.1 mg/100 g dw, respectively. Tocotrienols and tocopherols were identified, with concentrations of 173.1-347.0 mg/100 g dw and 468.7-913.4 mg/100 g dw. Fatty acids were the major non-polar compounds. All fractions significantly reduced matrix metalloproteinase-9 (MMP-9) activity. Although PPF had lower antioxidant potential (3-6 mmol Trolox/100 g dw), it inhibited AChE and BuChE by 23-30% compared to physostigmine salicylate. These findings suggest that pear pomace waste can be repurposed into functional products with valuable bioactive properties by re-introducing it in the food chain.

Physicochemical Properties of Dried and Powdered Pear Pomace

Pear pomace, a byproduct of juice production, represents a valuable reservoir of bioactive compounds with potential health benefits for humans. This study aimed to evaluate the influence of drying method and temperature on pear pomace, specifically focusing on the drying kinetics, grinding characteristics, color, phenolic profile (LC-MS/MS), and antioxidant activities of the powder. Drying using the contact method at 40 °C with microwave assistance demonstrated the shortest duration, whereas freeze-drying was briefer compared to contact-drying without microwave assistance. Freeze-drying resulted in brighter and more easily comminuted pomace. Lyophilized samples also exhibited higher total phenolic compound levels compared to contact-dried ones, correlating with enhanced antioxidant activity. Twenty-one phenolic compounds were identified, with dominant acids being quinic, chlorogenic, and protocatechuic. Flavonoids, primarily isoquercitrin, and rutin, were also presented. Pear pomace dried via contact at 60 °C contained more quinic and protocatechuic acids, while freeze-dried pomace at the same temperature exhibited higher levels of chlorogenic acid, epicatechin, and catechin. The content of certain phenolic components, such as gallic acid and epicatechin, also varied depending on the applied drying temperature.

Pear pomace soluble dietary fiber ameliorates the negative effects of high-fat diet in mice by regulating the gut microbiota and associated metabolites

The gut microbiota and related metabolites are positively regulated by soluble dietary fiber (SDF). In this study, we explored the effects of SDF from pear pomace (PP) on the regulation of gut microbiota and metabolism in high-fat-diet-fed (HFD-fed) C57BL/6J male mice. The results showed that PP-SDF was able to maintain the HFD disrupted gut microbiota diversity with a significant increase in Lachnospiraceae_UCG-006, Akkermansia, and Bifidobacterium spp. The negative effects of high-fat diet were ameliorated by PP-SDF by regulating lipid metabolisms with a significant increase in metabolites like isobutyryl carnitine and dioscoretine. Correlation analysis revealed that gut microbiota, such as Akkermansia and Lachnospiraceae_UCG-006 in the PP-SDF intervention groups had strong positive correlations with isobutyryl carnitine and dioscoretin. These findings demonstrated that PP-SDF interfered with the host's gut microbiota and related metabolites to reduce the negative effects caused by a high-fat diet.

Agri-Food Waste from Apple, Pear, and Sugar Beet as a Source of Protective Bioactive Molecules for Endothelial Dysfunction and Its Major Complications

Endothelial damage is recognized as the initial step that precedes several cardiovascular diseases (CVD), such as atherosclerosis, hypertension, and coronary artery disease. It has been demonstrated that the best treatment for CVD is prevention, and, in the frame of a healthy lifestyle, the consumption of vegetables, rich in bioactive molecules, appears effective at reducing the risk of CVD. In this context, the large amount of agri-food industry waste, considered a global problem due to its environmental and economic impact, represents an unexplored source of bioactive compounds. This review provides a summary regarding the possible exploitation of waste or by-products derived by the processing of three traditional Italian crops-apple, pear, and sugar beet-as a source of bioactive molecules to protect endothelial function. Particular attention has been given to the bioactive chemical profile of these pomaces and their efficacy in various pathological conditions related to endothelial dysfunction. The waste matrices of apple, pear, and sugar beet crops can represent promising starting material for producing "upcycled" products with functional applications, such as the prevention of endothelial dysfunction linked to cardiovascular diseases.

Methionine strengthens anti-inflammation of rice protein via depressing NF-κB activation and stimulating Msr expression in rats fed cholesterol-enriched diets

Oxidized low-density lipoprotein (ox-LDL) is an inducer of inflammation. To elucidate the link of depression of ox-LDL accumulation and anti-inflammatory function of rice protein (RP) whether dependent on methionine availability, growing and adult rats were fed RP and methionine-supplemented RP (RM) under cholesterol-enriched dietary condition. After two weeks feeding, RP and RMs exerted the anti-inflammatory effects through up-regulating IL-10, while RP and RMs significantly reduced ox-LDL levels and effectively suppressed the expressions of inflammatory mediators (COX-2, IL-1β, IL-6, TNF-α, iNOS). The anti-inflammatory molecular mechanism was to inhibit NF-κB activation and to simulate methionine sulfoxide reductase expression. Results showed, under cholesterol-enriched dietary condition, the anti-inflammatory action can be induced by RP and enhanced by methionine in growing and adult rats. The present study reveals a link of the decreased ox-LDL accumulation with the anti-inflammatory function of RP, which is dependent on methionine availability and independent of dietary cholesterol.

Pear pomace alleviated atopic dermatitis in NC/Nga mice and inhibited LPS-induced inflammation in RAW 264.7 macrophages

BACKGROUND/OBJECTIVES

Poorly regulated inflammation is believed to be the most predominant factor that can result in a wide scope of diseases including atopic dermatitis (AD). Despite many studies on the effect of pear pomace in obesity-related disorders including dysregulated gut microbiota, the protective effect of pear pomace in AD is still unknown. This study aimed to evaluate the effect of pear pomace ethanol extract (PPE) on AD by inhibiting inflammation.

MATERIALS/METHODS

In the in vivo experiment, 2, 4-dinitrochlorobenzene (DNCB) was applied to NC/Nga mice to induce AD-like skin lesions. After the induction, PPE was administered daily by oral gavage for 4 weeks. The clinical severity score, serum IgE levels, spleen weight, histological changes in dorsal skin, and inflammation-related proteins were measured. In the cell study, RAW 264.7 cells were pretreated with PPE before stimulation with lipopolysaccharide (LPS). Nitrite oxide (NO) production and nuclear factor kappa B (NF-kB) protein expression were detected.

RESULTS

Compared to the AD control (AD-C) group, IgE levels were dramatically decreased via PPE treatment. PPE significantly reduced scratching behavior, improved skin symptoms, and decreased ear thickness compared to the AD-C group. In addition, PPE inhibited the DNCB-induced expression of inducible nitrite oxide synthase (iNOS), the receptor for advanced glycation end products, extracellular signal-regulated kinase (ERK) 1/2, and NF-κB. PPE inhibited the LPS-induced overproduction of NO and the enhanced expression of iNOS and cyclooxygenase-2. Moreover, the phosphorylation of ERK1/2 and NF-κB in RAW 264.7 cells was suppressed by PPE.

CONCLUSIONS

These results suggest that PPE could be explored as a therapeutic agent to prevent AD.

A review of pears (Pyrus spp.), ancient functional food for modern times

BACKGROUND

Pears have been world-widely used as a sweet and nutritious food and a folk medicine for more than two millennia.

METHODS

We conducted a review from ancient literatures to current reports to extract evidence-based functions of pears.

RESULTS

We found that pears have many active compounds, e.g., flavonoids, triterpenoids, and phenolic acids including arbutin, chlorogenic acid, malaxinic acid, etc. Most of researchers agree that the beneficial compounds are concentrated in the peels. From various in vitro, in vivo, and human studies, the medicinal functions of pears can be summarized as anti-diabetic,-obese, -hyperlipidemic, -inflammatory, -mutagenic, and -carcinogenic effects, detoxification of xenobiotics, respiratory and cardio-protective effects, and skin whitening effects. Therefore, pears seem to be even effective for prevention from Covid-19 or PM2.5 among high susceptible people with multiple underlying diseases.

CONCLUSION

For the current or post Covid-19 era, pears have potential for functional food or medicine for both of communicable and non-communicable disease.