Impact of vinification procedure on fruit wine inhibitory activity against α-glucosidase

Anti-Diabetic Potential of Polyphenol-Rich Fruits from the Maleae Tribe-A Review of In Vitro and In Vivo Animal and Human Trials

The Maleae tribe consists of over one thousand species, including many well-known polyphenol-containing fruit crops with wide-ranging biological properties, e.g., apples (Malus), chokeberries (Aronia), pears (Pyrus), quinces (Cydonia, Chaenomeles), saskatoon (Amelanchier), loquats (Eriobotrya), medlars (Mespilus), rowans (Sorbus), and hawthorns (Crataegus). Considering the current interest in the concept of functional foods and the still-insufficient methods of diabetes management, the anti-diabetic potential of fruits has been studied intensively, including those of the Maleae tribe. This paper is the first comprehensive overview of this selected topic, covering articles published from 2000 to 2023 (131 articles in total). The first part of this review focuses on the potential mechanisms of action of fruits investigated so far (46 species), including their effects on tissue-specific glucose transport and the expression or activity of proteins in the insulin signalling pathway. The second part covers the phytocompounds responsible for particular fruits' activity-primarily polyphenols (e.g., flavonols, dihydrochalcones, proanthocyanidins, anthocyanins, phenolic acids), but also polysaccharides, triterpenes, and their additive and synergistic effects. In summary, fruits from the Maleae tribe seem promising as functional foods and anti-diabetic agents; however, their prospects for more expansive pro-health application require further research, especially more profound in vivo trials.

Comparison of the generation of α-glucosidase inhibitory peptides derived from prolamins of raw and cooked foxtail millet: In vitro activity, de novo sequencing, and in silico docking

Foxtail millet prolamin has been demonstrated to have anti-diabetic effects. In this study, we compared the generation of anti-α-glucosidase peptides derived from prolamins of raw and cooked foxtail millet (PRFM and PCFM). PRFM and PCFM hydrolysates (PRFMH and PCFMH) both exhibited α-glucosidase inhibitory activity. After ultrafiltration according to molecular weight (Mw), the fraction with Mw < 3 kDa in PCFMH (PCFMH_<3) showed higher α-glucosidase inhibitory activity than that in PRFMH (PRFMH_<3). The composition of α-glucosidase inhibitory peptides identified by de novo sequencing in PCFMH_<3 and PRFMH_<3 was compared by virtual screening, combining biological activity, net charge, grand average of hydropathicity (GRAVY), and key hydrophobic amino acids (Met, Pro, Phe, and Leu). We found that the proportion of peptides with excellent α-glucosidase binding force in PCFMH_<3 was higher than in PRFMH_<3. Overall, cooking may positively affect the generation of peptides that perform well in inhibiting α-glucosidase derived from foxtail millet prolamin.

Effective Therapeutic Verification of Crocin I, Geniposide, and Gardenia (Gardenia jasminoides Ellis) on Type 2 Diabetes Mellitus In Vivo and In Vitro

For many centuries, Gardenia (Gardenia jasminoides Ellis) was highly valued as a food homologous Chinese herbal medicine with various bioactive compounds, including crocin I and geniposide. However, the functional mechanism underlying the hypoglycemic effect of gardenia is absent in the literature. To evaluate the effect of gardenia and its different extracts on type 2 diabetes mellitus (T2DM) in in vivo and in vitro experiments, the dried gardenia powder was extracted using 60% ethanol and eluted at different ethanol concentrations to obtain the corresponding purified fragments. After that, the active chemical compositions of the different purified gardenia fragments were analyzed using HPLC. Then, the hypoglycemic effects of the different purified gardenia fragments were compared using in vitro and in vivo experiments. Finally, the different extracts were characterized using UPLC-ESI-QTOF-MS/MS and the mass spectrometric fragmentation pathway of the two main compounds, geniposide and crocin I, were identified. The experimental results indicated that the inhibitory effect of the 40% EGJ (crocin I) on the α-glucosidase was better than the 20% EGJ (geniposide) in vitro. However, the inhibitory effect of geniposide on T2DM was better than crocin I in the animal experiments. The different results in vivo and in vitro presumed potentially different mechanisms between crocin I and geniposide on T2DM. This research demonstrated that the mechanism of hypoglycemia in vivo from geniposide is not only one target of the α-glucosidase but provides the experimental background for crocin I and the geniposide deep processing and utilization.

The Leaves of Cyclocarya paliurus: A Functional Tea with Preventive and Therapeutic Potential of Type 2 Diabetes

Type 2 diabetes mellitus (T2DM) has become a universal and chronic global public health concern and causes multiple complex complications. In order to meet the rapidly growing demand for T2DM treatment, increased research has been focused on hypoglycemic drugs. Cyclocarya paliurus (Batal.) Iljinsk is the only living species of the genus Cyclocarya Iljinskaja, whose leaves have been extensively used as a functional tea to treat obesity and diabetes in China. An enormous amount of very recent pharmacological research on the leaves of C. paliurus has demonstrated that they carry out numerous biological activities, such as hypoglycemic, anti-inflammatory, and intestinal microbiota regulation. Multiple in vitro and in vivo studies have also shown that the extracts of C. paliurus leaves are innocuous and safe. This study aims to provide an up-to-date review of the botany, traditional uses, phytochemistry, pharmacological effects against diabetes, toxicology, and clinical studies of C. paliurus leaves, in hopes of promoting a better understanding of their role in the prevention and treatment of T2DM.

Identification, potency evaluation, and mechanism clarification of α-glucosidase inhibitors from tender leaves of Lithocarpus polystachyus Rehd

Lithocarpus polystachyus Rehd. known as Sweet Tea in China has attracted lots of interest for its good hypoglycemic effect and the potential as a hypoglycemic agent. Based on affinity separation-UPLC-Q-TOF-MS/MS, 54 potential α-glucosidase inhibitiors were identified and 44 were structurally determined. Out of them, 41 were identified for the first time from this plant including flavonoids, fatty acids, triterpenes, alkaloids, and coumarins. Enzyme assays revealed that flavonoids exhibited higher inhibitory activity against α-glucosidase than others with astilbin (IC₅₀ = 6.14 μg·mL^-1), morin (IC₅₀ = 8.46 μg·mL^-1), and naringenin (IC₅₀ = 10.03 μg·mL^-1) showing 2- to 4-fold higher potency than the positive control acarbose. They were proved as reversible inhibitors with mixed inhibition mechanism. K_i (K_i^') values and molecular dockings strongly supported the potency order of astilbin, morin and naringenin that showed in the enzyme assays.

Corylus avellana: A Source of Diarylheptanoids With α-Glucosidase Inhibitory Activity Evaluated by in vitro and in silico Studies

Corylus avellana hard shells, green leafy involucres, leaves, and male flowers have shown to be a source of diarylheptanoids, a class of natural products with promising biological activities. Cyclic diarylheptanoids, named giffonins, were isolated from the Italian cultivar "Tonda di Giffoni." Even if many efforts have been made to establish the chemistry of these compounds, little is known about their biological properties. Herein, the inhibitory effects of diarylheptanoids isolated from C. avellana byproducts against α-glucosidase enzyme were evaluated. Molecular docking experiments disclosed the establishment of several key interactions between all the screened diarylheptanoids and the protein counterpart, whose model was built through homology modeling procedure, thus rationalizing the detected inhibitory activities. Specifically, the most active compounds giffonin J (10), K (11), and P (16) were able to make both H-bonds and π-π stacking contacts with different residues belonging to the binding site responsible for the catalytic activity of the investigated enzyme. To highlight the occurrence of the bioactive diarylheptanoids in the extracts of C. avellana byproducts obtained by eco-friendly extractions, their LC-MS profiles were analyzed. LC-MS analysis showed how giffonin J (10), K (11), and P (16) occurred in the ethanol extract of the leaves, while in the extracts of shells and green leafy involucres only giffonin P (16) was evident. Moreover, the quantitative analysis of giffonin J (10), K (11), and P (16) in C. avellana byproducts was carried out by an analytical approach based on LC-ESI/QTrap/MS, using the Multiple Reaction Monitoring (MRM) experiment. These results prompt to evaluate C. avellana byproducts, especially the leaves, as a prospective source of bioactive diarylheptanoids for the development of functional ingredients for the treatment of diabetes.

Thermal treatment enhances the α-glucosidase inhibitory activity of bitter melon (Momordica charantia) by increasing the free form of phenolic compounds and the contents of Maillard reaction products

Inhibition of α-glucosidase can slow carbohydrate metabolism, which is known as an effective strategy for diabetes treatment. The aim of this study is to evaluate the effect of thermal treatment (50, 60, and 70℃) for 15 days on the α-glucosidase inhibitory activity of bitter melon. The results show that the bitter melon heated at 70℃ for 12 days had the best α-glucosidase inhibitory effect. However, the amount of free polyphenols, 5-hydroxymethyl-2-furfural (5-HMF), and the browning degree of bitter melon generally increased with the time (15 days) and temperature of the thermal treatment, which is positively related to their antioxidant and α-glucosidase inhibitory activities. In conclusion, aged bitter melon shows great α-glucosidase inhibitory activity, which may be related to the increased free form of the involved phenolic compounds and Maillard reaction products. This suggests that thermal processing may be a good way to enhance the application of bitter melon for diabetes treatment. PRACTICAL APPLICATION: The thermal processing of bitter melon provides an application for diabetes treatment. This study demonstrated that heat-treated bitter melon can lower the blood glucose level; therefore, it can be used as a potential anti-hyperglycemic and functional food.

Cassia auriculata leaf extract ameliorates diabetic nephropathy by attenuating autophagic necroptosis via RIP-1/RIP-3-p-p38MAPK signaling

Diabetic nephropathy (DN) is the most common manifestation of high glucose induced diabetes mellitus. In this study, we report the effects of Cassia auriculata ethanol leaf extract (CALE) on DN-associated cell toxicity and complications. The effects of CALE were screened in vitro using RGE cells. Cell viability was assessed using MTT and flow cytometry. Male Sprague-Dawley rats were divided into control, DN and treatment groups (n = 8). The DN and treatment groups received 60 mg/kg/bw of streptozotocin in citrate buffer, while the treatment group was administered 150 mg/kg/bw of CALE for 10 weeks. Biochemical analysis was conducted using spectrophotometry. Kidney tissues were analyzed using hematoxylin and eosin staining and transmission electron microscopy. CD365-KIM-1 expression was assessed using flow cytometry and signalling proteins were detected using western blotting. Treatment with 30-mM glucose reduced the viability of RGE cells in a time-dependent manner and increased the population of dead RGE cells. Cotreatment with CALE reduced cell death and glucose induced protein expression of LC3-II, RIP-1 and RIP-3 in a dose-dependent manner. In addition, CALE improved the biochemical complications, renal dysfunction and pathophysiology of rats with DN and partially or fully restored the expression of key DN-associated signalling proteins, such as KIM-1 LC3-II, RIP-1, RIP-3 and p-p38MAPK in kidney cells. CALE showed protective effects, and improved DN-associated complications in RGE cells under high glucose stress conditions, potentially by inhibiting autophagic-necroptosis signals. Additionally, CALE improved the biochemical and pathological features of kidney injury while reducing autophagic-necroptosis in rat renal cells via the LC3-II-RIP-p38MAPK pathway. PRACTICAL APPLICATIONS: Results from the current investigation will add information to the literature on glucose induced renal toxicity and the protective effects of CALE over the complications of diabetic nephropathy (DN). The mechanistic investigations of the study will add light on the autophagic/necroptosis signals in DN and open new routes of investigations to study the efficacy of CALE in diabetes-related complications.

Differences in berry skin and pulp cell wall polysaccharides from ripe and overripe Shiraz grapes evaluated using glycan profiling reveals extensin-rich flesh

Shiraz is a widely planted cultivar in many of the world's top wine regions where it is used for the production of top-quality single varietal or blended red wines. Cell wall changes during grape ripening and over-ripening have been investigated, particularly in the context of understanding berry deconstruction thereby facilitating the release of favorable compounds during winemaking. However, no information is available on cell wall changes during berry shrinkage in Shiraz. Glycan microarray technology was used to directly profile Shiraz berries for cell wall polysaccharide and glycoprotein epitopes. Skins and pulp tissues were profiled separately and revealed that whereas the skin was rich in pectins and xyloglucans, the pulp tissues were mainly composed of extensin glycoproteins. Overripe (26-28°B) berries, particularly those from the warmer region site, revealed degradation of their pectin and extensin epitopes.

The antidiabetic potential of endophytic fungi: Future prospects as therapeutic agents

Diabetes mellitus is one of the most common systemic diseases in the world, and it occurs when the body becomes resistant to insulin or does not make enough insulin. As described by the World Health Organization, diabetes mellitus of all types has exponentially grown in the past decades across the globe and it is estimated to be 629 million by 2045. Despite this alarming prevalence of diabetes mellitus, there is still the lack of harmless preventive medicines. Natural products and compounds obtained from plants, fungi, bacteria, and other living organisms have been used for many decades in folklore medicine to prepare a varied range of natural formulations to treat multiple diseases and illnesses. Endophytic fungi reside inside the plant while causing no harm to the host plant and are relatively less explored as the primary source for the bioactive metabolites such as anticancer, antioxidant, antimicrobial, antidiabetic, and industrial enzymes. This mini-review summarizes the potential of compounds and extracts from endophytic fungi against diabetes mellitus. Not much research has been dedicated in-depth understanding of the role of extracts of endophytic fungi and their effect on diabetes mellitus. Therefore, this article will focus on recent work and warrant further commentaries on the published articles.

Human clinical trial to assess the effect of consumption of multigrain Indian bread on glycemic regulation in type 2 diabetic participants

The efficacy of multigrain flatbread in regulating the lipid profile and carbohydrate homeostasis among type 2 diabetic patients was studied in 100 type 2 diabetic participants. The results revealed that the anthropometric parameters remained unaltered in both test and control groups. The fasting blood glucose levels (140.70 ± 8.43 versus 132.89 ± 5.63 mg/dl) did not significantly decrease. In contrast, the insulin levels (12.96 ± 1.06 versus 10.83 ± 1.03 μIU/ml) and HbA1c levels (8.01 ± 0.27 versus 7.40 ± 0.21%) in the test group decreased significantly, and it was associated with a decrease in insulin resistance. The LDL levels in the test group decreased after the intervention (116.0 ± 5.67 versus 98.7 ± 5.68 mg/dl), while triglycerides and VLDL increased significantly and HDL levels remained unaltered. A significant decrease in average blood pressure (systolic/diastolic) was noticed among the test group participants. The human RBP4 and hs-CRP remained unaltered. PRACTICAL APPLICATIONS: Millets are rich in fibers, has complex carbohydrate, protein, and is lower in fat content. Millets provide a wide range of nutrients, phytochemicals, and are gluten-free with low glycemic nature. Their intake can reduce factors such as insulin resistance and oxidative stress responsible for the pathogenesis of type 2 diabetes and cardiovascular diseases. Our study indicated the use of multigrain flatbreads prepared from millets helped reduce serum insulin, LDL cholesterol, HbA1c levels, and incidentally blood pressure levels with a significant increase in insulin sensitivity in type 2 diabetes participants. The results suggest using the multigrain flatbread meal as a food supplement or meal replacer in diabetic participants in terms of glucose control and insulin sensitivity.

Zanthoxylum alkylamides improve amino acid metabolism in type 2 diabetes mellitus rats

To investigate the effect of Zanthoxylum alkylamides (ZA) on amino acid metabolism of type 2 diabetes mellitus (T2DM), the present study was performed with T2DM rats model induced with high fat and sugar fodder combined with low-dose of streptozotocin. ZA were fed to rats at three different doses of 2, 4, and 8 mg/kg for 28 days and metformin was fed to rats at 135 mg/kg as positive control. The results showed that compared with the normal control, the amino acid levels and the expression of related carrier genes were disordered in T2DM rats. Compared with the model, different doses of ZA could significantly resist (p < .05) the decrease in body weight of T2DM rats and improve hyperglycemia, with the best result observed with the high dose (8 mg/kg). Different doses of ZA could ameliorate the levels of 19 kinds of amino acid in the plasma, jejunum, liver, and skeletal muscle of T2DM rats by regulating the expression of related amino acid transporters including LAT1, SNAT2, CAT1, et al. to thereby ameliorating amino acid metabolism disorder in T2DM rats. PRACTICAL APPLICATIONS: Previous studies showed that Zanthoxylum alkylamides (ZA) could promote the amino acid metabolism in the jejunum of healthy SD rats, improve protein metabolism disorder of type 1 diabetic rats, and also reduce the risk of metabolic syndrome in fat rats model. Herein, we investigated the effect of ZA on amino acid metabolism in type 2 diabetes mellitus (T2DM) rats. The results indicated that ZA could remarkably improve the abnormal expression of amino acid carriers in the jejunum, liver, and skeletal muscle, thereby ameliorating the disorder of amino acid metabolism in the plasma, jejunum, liver, and skeletal muscle of T2DM rats. Therefore, ZA are potential antidiabetic food/medicine product for the T2DM treatment.

Aspergillus nidulans: A Potential Resource of the Production of the Native and Heterologous Enzymes for Industrial Applications

Aspergillus nidulans is a filamentous fungus that is a potential resource for industrial enzymes. It is a versatile fungal cell factory that can synthesize various industrial enzymes such as cellulases, β-glucosidases, hemicellulases, laccases, lipases, proteases, β-galactosidases, tannases, keratinase, cutinases, and aryl alcohol oxidase. A. nidulans has shown the potential to utilize low-cost substrates such as wheat bran, rice straw, sugarcane bagasse, rice bran, coir pith, black gram residue, and chicken feathers to produce enzymes cost-effectively. A. nidulans has also been known as a model organism for the production of heterologous enzymes. Several studies reported genetically engineered strains of A. nidulans for the production of different enzymes. Native as well as heterologous enzymes of A. nidulans have been employed for various industrial processes.

Effect of Saccharomyces cerevisiae, Torulaspora delbrueckii and malolactic fermentation on fermentation kinetics and sensory property of black raspberry wines

Alcoholic fermentation (AF) and malolactic fermentation (MLF) both have significant influence on the production of black raspberry wine. In this study, three microbes associated with AF and MLF including S. cerevisiae, T. delbrueckii and O. oeni were used to investigate their combined effect on basic compositional, volatile and sensory property of black raspberry wine, and four fermentation trials including single S. cerevisiae inoculation plus spontaneous MLF (BSU) and controlled MLF with O. oeni (BSO), sequential culture of T. delbrueckii and S. cerevisiae plus spontaneous MLF (BTSU) and controlled MLF (BTSO) were tested and compared. Fermentation results showed MLF in BSU, BSO and BTSO were successful, with respective period of 40, 25 and 23 days, whereas a stuck MLF occurred in BTSU. Volatile compounds were determined by HS-GC-IMS method, with a total of 45 aromas identified. BTSO was distinguished by a significant higher signal intensity of many fruity esters and a lower production of several alcohols and terpenes, which was in agreement with its perception result of strong 'fruity' and slight note of 'solvent' and 'herbaceous' during quantitative descriptive analysis. On the contrary, BSU was found to reinforce the synthesis of most detected volatiles, resulting in the enhancement of both beneficial and off-flavour compounds, therefore scoring lower in the 'global aroma' descriptor. Principal component analysis showed BSU and BSO were similar in the volatile composition, whereas BTSO was quite different. Overall, BTSO had greater potential to be used in the production of black raspberry wine.

Valorization of Fruits by-products to Unconventional Sources of Additives, Oil, Biomolecules and Innovative Functional Foods

Owning to the increase in the world population as well as the consumer's awareness on the health benefits of consumption of fruits, the demand for both fresh and processed fruits has been increased. The by-product and waste streams generated from fruit processing industries are extremely diverse, owning mainly to different fruits varieties and the wide range of the processes employed towards the production of the end fruit-based products. Due to the increasing production and processing of fruits, disposal of waste and by-product streams has become a serious issue, since these materials are prone to microbial spoilage. Also, the inappropriate waste management practices pose severe environmental issues. Furthermore, the costs of drying and storage of fruit processing residues are economically limiting factors hindering their further exploitation. Therefore, fruit processing by-products such as peels, seeds and unused flesh are often utilized as fertilizers. On the other hand, plant residues contain biomolecules such as vitamins, proteins, minerals, antioxidants and aromatic oil. Recovery of bioactive compounds holds a great potential for their usage in food industry as functional ingredients and nutraceuticals or in pharmaceutical and in cosmetic applications. So, valorization of plant fruit processing by-products to high-value added compounds, constitute a promising alternative not only for addressing fruit residues management issues but also leading to the production of functional food products of high nutritional value, with several potential beneficial health effects. The aim of this paper is to highlight current trends in addressing environmental issues caused by the production of high volumes of specific categories of fruit processing waste streams by investigating their potential usage as natural raw materials for the recovery of valuable bioactive compounds (such as polyphenols, dietary fibers or aromatic oil). The extracted nutrients may be used in the industrial food sector for the production of functional foods, nutraceuticals or even as health promoting natural pharmaceutical ingredients or additives for the production of innovative enriched foods. Highlights: • Fruit processing by product streams are rich in bioactive compounds. • Integration of fruit by-products and waste streams to value added products such as additives, unconventional oil, bioactive compounds and novel functional products is a very interesting approach regarding fruit processing residues exploitation. • Recovering of biomolecules from fruit residues by non-thermal processes could lead to the efficient production of highly purified functional ingredients. • Negative-valued fruit processing residues could be recycled for the production of health promoting value added products.

Antioxidative and Hypoglycemic Effect of Ta-ermi Extracts on Streptozotocin-Induced Diabetes

INTRODUCTION

The purpose of the present study was to reveal the potential positive effect of the Ta-ermi extracts on oxidative stress and streptozotocin (STZ)-diabetic mice and rats treated with Ta-ermi water- and alcohol-extracts.

METHODS

The study was carried out using three experimental model: 1) in vitro experiments whereby Ta-ermi extracts were incubated with free radical generators such as 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to evaluate Ta-ermi's antioxidant effects; 2) testing the hypoglycemic effects of Ta-ermi extracts in streptozotocin (STZ)-induced diabetic mice; and 3) testing the beneficial effects of Ta-ermi extracts on mitochondrial complex I function using STZ-diabetic rats.

RESULTS

In vitro antioxidant experiments showed that both of the extracts could scavenge free radicals and exhibited inhibitory effects on glucosidase and aldose reductase with differential effects between water extract and alcohol extract. In the STZ mouse diabetic model, both the water- and alcohol-extracts attenuated body weight decrease, decreased blood glucose levels in a concentration-dependent manner, improved insulin sensitivity, and increased oral glucose tolerance ability. In the STZ-diabetic rat model, both the water- and alcohol-extracts were found to be able to lower blood glucose levels in the diabetic animals with no effects on body weight changes. Moreover, in the STZ-diabetic rats, both the water- and alcohol-extracts of Ta-ermi could inhibit the increase of mitochondrial NADH/ubiquinone oxidoreductase (complex I) activity in the pancreas and enhanced complex I activity in the liver but showed no effect on lung or kidney mitochondrial complex I.

DISCUSSION

The present study points to the potential medicinal value of Ta-ermi's water and alcohol extracts in lowering blood glucose and decreasing diabetic oxidative stress. One limitation of our study is that the compound or compounds that actually have this beneficial effect in the extracts remain unknown at this time. Therefore, the future studies should be focused on the identification of the components in the extracts that exhibit anti-oxidative and hypoglycemic effects.

CONCLUSION

Taken together, our studies using different experimental paradigms indicate that Ta-ermi extracts possess antioxidant and anti-diabetic properties and may be employed as functional food ingredients for the remission of diabetes.