(Poly)phenolic compounds and antioxidant activity of white (Morus alba) and black (Morus nigra) mulberry leaves: Their potential for new products rich in phytochemicals

Fortification of yogurt with mulberry leaf extract: Effects on physicochemical, antioxidant, microbiological and sensory properties during 21-days of storage

Mulberry leaves are medicinal and edible, with many physiological functions. To improve the potential function of yogurt, the effects of mulberry leaf extract (MLE) incorporation on the fermentation kinetics, physicochemical, antioxidant properties, and sensory parameters of yogurt were evaluated. The results showed that 0.1-0.3 % MLE improved the acidification rate and shortened the fermentation process. The addition of MLE significantly increased the values of total titratable acids, water holding capacity (WHC), total phenolic content and antioxidant capacities of the yogurt (p＜0.05). Specifically, the WHC values of 0.1 % MLE added yogurt were 1.33-1.41 times that of the control over 21 days of storage. In addition, MLE changed the texture and sensory quality of yogurt, resulting in light green, more stable products. Compared to the control, the yogurt with an appropriate concentration of MLE (0.1 % and 0.2 %) showed stable microbiological properties, and the survival of lactic acid bacteria in the yogurt was able to maintain a stable probiotic count of 108 CFU/g over 21 days of shelf life. The yogurt containing 0.1 % MLE achieved a good balance between the physicochemical and sensory qualities of the yogurt, and the use of MLE as an ingredient in yogurt production was a step towards the development of healthier dairy products.

Effects of in vitro simulated digestion and fecal fermentation on the structure and regulating the glucose and lipid activity of a polysaccharide from Mori Folium

Mori folium, as a homologous drug-food, has hypoglycemic and lipid-lowering activity. Polysaccharides are the main bioactive ingredient of the Mori folium that exhibit diverse biological activities. In this study, a homogeneous polysaccharide (MP4) was purified and characterized from Mori folium. The changes of MP4 affected by saliva, simulated gastrointestinal juice, and human fecal fermentation, including physicochemical property or its bioactivity, were systematically investigated. Meanwhile, the influence of fermentation on the bioactivity were evaluated. The results showed that the backbone of MP4 is mainly composed of →4)-α-D-GalpA-(1→ residues. The molecular weight, the levels of reducing sugar content and free monosaccharides of MP4 exhibited no significant differences indicating that gastrointestinal digestion has a minimal effect on the physicochemical characteristics of MP4. However, during in vitro gut microbiota fermentation, MP4 are significantly degraded and utilized by gut microbiota, showing increased the production of short-chain fatty acids, notably acetic acid and propionic acid. The relative abundance of beneficial bacteria such as Bacteroidetes and Actinobacteria were significantly increased, whereas the levels of pathogenic bacteria such as Fusobacteria and Megamonas were significantly decreased, which changed the composition of the gut microbiota. The Firmicutes/Bacteroides ratio was also decreased significantly. Interestingly, after in vitro fermentation, the α-glucosidase inhibitory activity was increased, the lipase inhibitory activity and cholesterol adsorption activity was decreased. Correlation analysis showed that the relative abundance of some bacteria was significantly correlated with the bioactivities. These results provide a basis for the development of Mori folium polysaccharides as functional probiotic products.

Biological potential, chemical profiling, and molecular docking study of Morus alba L. extracts

Morus alba L. is a plant with a long history of dietary and medicinal uses. We hypothesized that M. alba possesses a significant biological potential. In that sense, we aimed to generate the chemical, antimicrobial, toxicological, and molecular profile of M. alba leaf and fruit extracts. Our results showed that extracts were rich in vitamin C, phenols, and flavonoids, with quercetin and pterostilbene concentrated in the leaf, while fisetin, hesperidin, resveratrol, and luteolin were detected in fruit. Extracts exhibited antimicrobial activity against all tested bacteria, including multidrug-resistant strains. The widest inhibition zones were in Staphylococcus aureus ATCC 33591. The values of the minimum inhibitory concentration ranged from 15.62 μg/ml in Enterococcus faecalis to 500 μg/ml in several bacteria. Minimum bactericidal concentration ranged from 31.25 μg/ml to 1000 μg/ml. Extracts impacted the biofilm formation in a concentration-dependent and species-specific manner. A significant difference in the frequency of nucleoplasmic bridges between the methanolic extract of fruit (0.5 μg/ml, 1 μg/ml, 2 μg/ml), as well as for the frequency of micronuclei between ethanolic extract of leaf (2 μg/ml) and the control group was observed. Molecular docking suggested that hesperidin possesses the highest binding affinity for multidrug efflux transporter AcrB and acyl-PBP2a from MRSA, as well as for the SARS-CoV-2 Mpro. This study, by complementing previous research in this field, gives new insights that could be of great value in obtaining a more comprehensive picture of the Morus alba L. bioactive potential, chemical composition, antimicrobial and toxicological features, as well as molecular profile.

Effects of Fermentation with Eurotium cristatum on Sensory Properties and Flavor Compounds of Mulberry Leaf Tea

Mulberry leaf tea (MT) is a popular Chinese food with nutrition and medicinal functions. Solid-state fermentation with Eurotium cristatum of MT (FMT) can improve their quality. Differences in chromaticity, taste properties, and flavor characteristics were analyzed to evaluate the improvements of the sensory quality of FMT. After fermentation, the color of the tea infusion changed. The E-tongue evaluation results showed a significant decrease in unpleasant taste properties such as sourness, bitterness, astringency, and aftertaste-bitterness, while umami and saltiness taste properties were enhanced post-fermentation. Aroma-active compounds in MT and FMT were identified and characterized. A total of 25 key aroma-active compounds were screened in MT, and 2-pentylfuran showed the highest relative odor activity value (ROAV). A total of 26 key aroma-active compounds were identified in FMT, and the newly formed compound 1-octen-3-one showed the highest ROAV, which contributed to FMT's unique mushroom, herbal, and earthy flavor attributes. 1-octen-3-one, (E)-2-nonenal, trimethyl-pyrazine, 2-pentylfuran, and heptanal were screened as the potential markers that contributed to flavor differences between MT and FMT. E. cristatum fermentation significantly altered the sensory properties and flavor compounds of MT. This study provides valuable insights into the sensory qualities of MT and FMT, offering a theoretical basis for the development of FMT products.

Biosynthesis and Pharmacological Activities of the Bioactive Compounds of White Mulberry (Morus alba): Current Paradigms and Future Challenges

Traditional natural products have been the focus of research to explore their medicinal properties. One such medicinally important plant is the white mulberry, Morus alba, widely distributed in the Asian subcontinent. It is one of the most cultivated species of mulberry tree and has attracted more focus from researchers because of its abundance in phytochemicals as well as multipurpose uses. The leaves, fruits and other parts of the white mulberry plant act as a source of valuable bioactive compounds like flavonoids, phenolic acids, terpenoids and alkaloids. These secondary metabolites have manifold healthy uses as they possess antioxidant, anti-inflammatory, antidiabetic, neutrotrophic, and anticancer properties. Despite the increasing scientific interest in this plant, there are very few reviews that highlight the phytochemistry and biological potential of white mulberry for biomedical research. To this end, this review elaborates the phytochemistry, biosynthetic pathways and pharmacological activities of the glycoside flavonoids of Morus alba. A comprehensive analysis of the available literature indicates that Morus alba could emerge as a promising natural agent to combat diverse conditions including diabetes, cancer, inflammation and infectious diseases. To achieve such important objectives, it is crucial to elucidate the biosynthesis and regulation mechanisms of the bioactive compounds in white mulberry as well as the multifaceted pharmacological effects attributed to this plant resource. The present review paper is intended to present a summary of existing scientific data and a guide for further research in the phytochemistry and pharmacology of white mulberry. Further, a biosynthetic pathway analysis of the glycoside flavonoid in mulberry is also given. Lastly, we discuss the pros and cons of the current research to ensure the prudent and effective therapeutic value of mulberry for promoting human and animal health.

Mulberry leaf and its effects against obesity: A systematic review of phytochemistry, molecular mechanisms and applications

BACKGROUND

Obesity and hyperlipidemia can induce a variety of diseases, and have become major health problems worldwide. How to effectively prevent and control obesity has become one of the hot-spots of contemporary research. Mulberry leaf is the dried leaf of Morus alba L., which is approved by the Ministry of Health as a "homology of medicine and food", rich in diverse active constituents and with a variety of health effects including anti-obesity and anti-hyperlipidemia activities.

PURPOSE

The review attempts to summarize and provide the molecular basis, mechanism, safety and products for further exploration and application of mulberry leaf on the treatment on the control of weight gain and obesity.

METHODS

This review is conducted by using ScienceDirect, PubMed, CNKI and Web of Science databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Based on the research progress of domestic and foreign scholars, the effective phytochemicals, molecular mechanisms and product applications of mulberry leaf in the prevention and treatment of obesity and related metabolic diseases were summarized.

CONCLUSION

Mulberry leaf has excellent medicinal and health care value in obesity treatment. However, its pharmacodynamic substance basis and molecular mechanisms need to be further studied.

Exploring Phenolic Compounds in Crop By-Products for Cosmetic Efficacy

Phenolic compounds represent a group of secondary metabolites that serve essential functions in plants. Beyond their positive impact on plants, these phenolic metabolites, often referred to as polyphenols, possess a range of biological properties that can promote skin health. Scientific research indicates that topically using phenolics derived from plants can be advantageous, but their activity and stability highly depend on storage of the source material and the extraction method. These compounds have the ability to relieve symptoms and hinder the progression of different skin diseases. Because they come from natural sources and have minimal toxicity, phenolic compounds show potential in addressing the causes and effects of skin aging, skin diseases, and various types of skin damage, such as wounds and burns. Hence, this review provides extensive information on the particular crops from which by-product phenolic compounds can be sourced, also emphasizing the need to conduct research according to proper plant material storage practices and the choice of the best extracting method, along with an examination of their specific functions and the mechanisms by which they act to protect skin.

Bioactivity, phytochemistry studies and subacute in vivo toxicity of ethanolic leaf extract of white mulberry (Morus alba linn.) in female mice

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional uses of Morus alba L. leaf extracts (MLE) have been reported for treating hyperglycaemia and diabetes. Phytochemical compounds in the leaves demonstrated the ability to enhance insulin sensitivity and β-cell secretory function, suggesting their potential value in reducing blood glucose and treating diabetes. However, the phytochemical constituents and safety of the herbal medicines need to be verified in each experimental field from different growing areas. Studies on the phytochemistry and toxicity of Morus alba leaves in Southeast Asia, especially in Brunei, have never been investigated.

AIM OF THE STUDY

This study aimed to investigate the bioactivity and phytochemistry of Morus alba ethanolic leaf extract from Brunei Darussalam and its subacute toxic effects in the Institute of Cancer Research (ICR) female mice.

MATERIALS AND METHODS

The phenolic yield and antioxidant of the extract were analysed. Meanwhile, liquid chromatography-mass spectrometry and high-performance liquid chromatography were utilised to determine the phenolic compound of the MLE. In the subacute toxicity study, twenty-five female mice were randomly divided into five groups: the control group, which received oral gavage of 5% dimethyl sulfoxide solvent (DMSO), and the MLE treatment group, which received the extract at a dose of 125, 250, 500 and 1000 mg/kg. Physiology, haematology, biochemistry, and histology were evaluated during the study.

RESULTS

Morus alba leaf depicted total phenolic 10.93 mg gallic acid equivalents (GAE)/g dry weight (DW), flavonoid 256.67 mg quercetin equivalents (QE)/g DW, and antioxidant bioactivity content of 602.03 IC50 μg/mL and 13.21 mg Fe2+/g DW. Twenty compounds in the Morus alba ethanolic leaf extract were identified, with chlorogenic acid (305.60 mg/100 g DW) as the primary compound. As for subacute toxicity in this study, neither mortality nor haematological changes were observed. On the other hand, administration of 500 and 1000 mg/kg MLE resulted in mild hepatocellular injury, as indicated by a significant (p < 0.05) increase in liver enzyme activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The histopathological score showed mild hepatocellular necrosis in administering 250, 500, and 1000 mg/kg of MLE. The parameters of renal injury were within normal limits, with the increase in eosinophilic cytoplasm observed in the histological scoring at 1000 mg/kg of MLE.

CONCLUSIONS

Morus alba leaf extract showed abundant polyphenols. In a study on subacute toxicity, MLE caused mild hepatotoxicity in mice. The toxic effect of the extract may be due to kaempferol and chlorogenic acid compounds. The 125 mg/kg MLE dose was safe with no adverse effects.

Morusacerane: A new gammacerane triterpenoid from the trunk of Morus Alba linn. with α-glucosidase inhibitory activity

This phytochemistry investigation on the trunk of Morus alba L. resulted in the isolation of three triterpenoids, including a new gammacerane triterpenoid - morusacerane (1); along with two known compounds of betulinic acid (2) and ursolic acid (3). The structure elucidation was thoroughly conducted based on 1D, 2D-NMR and HRESIMS spectra, followed by a comparison with existing literatures. The evaluation on α-glucosidase inhibitory exhibited the great potential of the application of these isolated compounds in diabetes treatments. The results show that morusacerane (1), betulinic acid (2), and ursolic acid (3) demonstrate the strong inhibitory with the IC50 values of 106.1, 11.12, and 7.20 μM, respectively. All of these compounds interacted well with the allosteric site enzyme α-glucosidase MAL32 through H-bonds and hydrophobic interaction.

How Does In Vitro Digestion Change the Amount of Phenolics in Morus alba L. Leaf? Analysis of Preparations and Infusions

The application of Morus alba L. in traditional oriental medicine and cuisine has resulted in numerous studies on its health-promoting effects. However, if the process is not monitored by the manufacturers, the processing of the leaves alters the obtained health-promoting properties and results in different health qualities in the final composition of dietary supplements. This article aims to analyze changes (using the HPLC/DAD method) in the proposed conditioned mulberry leaves in terms of key compounds (phenolic acids and flavonols) responsible for antioxidant activity after being digested in in vitro conditions. The analyzed material was leaves of white mulberry (Morus alba L.) cv. Żółwińska wielkolistna, conditioned (1-4 h) and non-conditioned. The conditioning process of mulberry proposed here, e.g., for industry production, resulted in variable transformations of polyphenols during in vitro digestion. For many polyphenols, especially those shown in the highest amounts, significant correlations were found between their content and conditioning, as well as the stage of digestion. In the case of mulberry infusions, the amounts of individual polyphenols were several times lower than in the preparations, which was due to the degree of dilution. Their amounts tended to decrease in the course of digestion. Taking this into account, it seems justified to continue research on the in vivo bioavailability of bioactive components from conditioned Morus alba L. leaves.

The influence of ambient temperature and polyphenols from plant leaves on growth and the response to oxidative and nitrosative stress in African nightcrawler earthworm, Eudrilus eugeniae (Kinberg, 1867)

Earthworms are one of the organisms that may be affected by climate change. Finding ways to help them deal with this problem is, therefore, important and necessary. The objective of this experiment was to understand the influence of ambient temperature and polyphenols from mulberry (Morus alba L.), almond (Terminalia catappa L.) and cassava (Manihot esculenta (L.) Crantz) leaves on growth, ferric reducing antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and nitric oxide (NO) concentration of the African night crawler, Eudrilus eugeniae (Kinberg, 1867) earthworm. The earthworms were cultured in 2 different conditions of ambient temperature, and in 4 types of substrate i.e. dairy cow faeces (BS), dairy cow faeces + mulberry leaves (BS + MA), almond leaves (BS + TC), and cassava leaves (BS + ME), respectively. At week 2 of the experiment, body weight, FRAP, MDA, H₂O₂ and NO were measured in the earthworms. It was found that the body weight gain (BWG) of the earthworms cultured in BS at cyclical temperature (26 + 1^oC - 34 + 1^oC - 26 + 1^oC, CyT) was higher than the constant temperature (26 ± 1 °C, CoT) (P < 0.05). FRAP of earthworms cultured in BS + TC was higher than in other groups (P < 0.05). MDA of earthworms cultured at CyT was higher than ambient temperature at CoT (P < 0.05). At CyT, the MDA of earthworms cultured in BS + MA was higher than that of those cultured in BS, BS + TC and BS + ME (P < 0.05). NO of earthworms at CoT was higher than at CyT(P < 0.05). At CoT, the NO of earthworms cultured in BS + TC was lower than that of those cultured in BS + MA and BS + ME (P < 0.05). H₂O₂ of earthworms at CoT was higher than those at CyT (P < 0.05). The level of H₂O₂ of the earthworms cultured in BS + ME at CoT was higher than at CyT (P < 0.05). In addition, the H₂O₂ of earthworms cultured in both ambient temperatures and cultured in BS + MA was higher than the other groups (P < 0.05). These phenomena indicated that low and high ambient temperatures induced nitrosative and oxidative stress in earthworms, respectively. Mulberry leaves are toxic to earthworms. On the other hand, almond leaves could reduce nitrosative stress in earthworms. While at the CoT, cassava leaves induced the production of H₂O₂ in the earthworms.

Morus alba fruit diet ameliorates cognitive deficit in mouse model of streptozotocin-induced memory impairment

Mounting evidence shows that dietary intake of fruits with polyphenols is beneficial to improve impaired memory functions. This study explored the preventive as well as therapeutic effects of diet enriched with Morus alba fruits extract (DEMA) in streptozotocin (STZ) induced mouse model of memory impairment. The study consisted of two facets: one aspect consisted of pretreatment of animals with DEMA for two weeks followed by STZ (i.c.v) intervention and the second phase involved induction of dementia with STZ (i.c.v) followed by treatment with DEMA for 14 days. Cognitive functions of animals were measured by Morris Water Maze test and to delineate the associated mechanism of action, brain biochemical estimations (acetyl-cholinesterase activity, myeloperoxidase activity, thiobarbituric acid reactive species, superoxide dismutase activity, reduced glutathione and nitrite/nitrate) and histopathological studies (haematoxylin and eosin staining) were performed. Pre- and post- treatment with DEMA significantly prevented and attenuated, respectively, the detrimental effects of STZ on mice brain. The results demonstrated that dietary modification, by incorporation of M. alba fruits, reduces the incidence and aids in treatment of memory disorder in mice by reducing central cholinergic activity, decreasing oxidative stress and preventing neurodegeneration.

The phenolic components extracted from mulberry fruits as bioactive compounds against cancer: A review

In Asia, mulberry has long been used to treat various infectious and internal ailments as a traditional medication. The compounds found in it have the potential to improve human health. Because there is no approved and defined evaluation procedure, it has not been formally or scientifically recognized. As a result of these investigations, a new frontier in traditional Chinese medicine has opened up, with the possibility of modernization, for the interaction between active components of mulberry and their biological activities. These studies have used current biotechnological technologies. For ages, mulberry has been used as an herbal remedy in Asia to cure various diseases and internal disorders. It has a high concentration of bioactive chemicals that benefit human health. The most abundant phenolic components extracted from white mulberry leaves are flavonoids (Kuwanons, Moracinflavans, Moragrols, and Morkotins), phenolic acids, alkaloids, and so forth. Flavonoids, benzofurans, chalcones, and alkaloids have been discovered to have cytotoxic effects on human cancer cell lines. There is growing evidence that mulberry fruits can potentially prevent cancer and other aging-related disorders due to their high concentration of bioactive polyphenolic-rich compounds and macro and micronutrients. Anthocyanins are rapidly absorbed after eating, arriving in the plasmalemma within 15-50 min and entirely removed after 6-8 hr. Due to a lack of an approved and consistent technique for its examination, it has yet to be formally or scientifically recognized. The mulberry plant is commercially grown for silkworm rearing, and less attention is paid to its bioactive molecules, which have a lot of applications in human health. This review paper discusses the phenolic compounds of white mulberry and black mulberry in detail concerning their role in cancer prevention.

Identification of geographic origins of Morus alba Linn. through surfaced enhanced Raman spectrometry and machine learning algorithms

The leaves of Morus alba Linn., which is also known as white mulberry, have been commonly used in many of traditional systems of medicine for centuries. In traditional Chinese medicine (TCM), mulberry leaf is mainly used for anti-diabetic purpose due to its enrichment in bioactive compounds such as alkaloids, flavonoids and polysaccharides. However, these components are variable due to the different habitats of the mulberry plant. Therefore, geographic origin is an important feature because it is closely associated with bioactive ingredient composition that further influences medicinal qualities and effects. As a low-cost and non-invasive method, surface enhanced Raman spectrometry (SERS) is able to generate the overall fingerprints of chemical compounds in medicinal plants, which holds the potential for the rapid identification of their geographic origins. In this study, we collected mulberry leaves from five representative provinces in China, namely, Anhui, Guangdong, Hebei, Henan and Jiangsu. SERS spectrometry was applied to characterize the fingerprints of both ethanol and water extracts of mulberry leaves, respectively. Through the combination of SERS spectra and machine learning algorithms, mulberry leaves were well discriminated with high accuracies in terms of their geographic origins, among which the deep learning algorithm convolutional neural network (CNN) showed the best performance. Taken together, our study established a novel method for predicting the geographic origins of mulberry leaves through the combination of SERS spectra with machine learning algorithms, which strengthened the application potential of the method in the quality evaluation, control and assurance of mulberry leaves.

Comprehensive Analysis of Antioxidant and Hepatoprotective Properties of Morus nigra L

The framework of this study was a comprehensive investigation of Morus nigra L. extracts, with the aim to establish the correlation between chemical composition and antioxidant/hepatoprotective activity of a series of black mulberry extracts obtained from aerial parts of the plant. Black mulberry leaf (MLEE), bark (MBEE), juice (MJ) and fresh fruit (MFEE) extracts were obtained using the conventional Soxhlet extraction, while the supercritical CO₂ extraction procedure was employed for preparation of the seed oil (MSO). Analysis of the chemical composition was performed using spectrophotometric, HPLC and GC methods. For the evaluation of antioxidant activity, in vitro FRAP and DPPH assays were applied. In Haan strain NMRI mice with streptozotocin-induced oxidative stress, in vivo antioxidant activity and liver tissue integrity were examined. The content of polyphenolic compounds was the highest in MBEE (68.3 ± 0.7 mgGAE/g) with the most abundant compounds being polyphenolic acids, followed by MLEE (23.4 ± 0.5 mgGAE/g) with the flavonoids isoquercetin and rutin being present in a significant amount. An analysis of MSO revealed a high content of γ-linoleic acid. The highest antioxidant activity in vitro (FRAP and DPPH) was observed for MLEE, MBEE and MSO. Beneficial effects were confirmed in vivo, with lower values of hepatosomatic index, potentiation of the activity of the enzymes superoxide dismutase and catalase, a lower rate of lipid peroxidation and reduced positivity for the P450 enzyme in animals treated with MLEE, MBEE and MSO. Black mulberry leaf and bark extracts as well as seed oil exhibited significant antioxidant activity. Apart from the confirmed biological properties of the fruit and leaf extracts, the observed activities of black mulberry seed oil and bark extract imply its importance as a sustainable source of phytochemicals.

Analysis of White Mulberry Leaves and Dietary Supplements, ATR-FTIR Combined with Chemometrics for the Rapid Determination of 1-Deoxynojirimycin

Diabetes mellitus is a metabolic disease affecting more people every year. The treatment of diabetes and its complications involve substantial healthcare expenditures. Thus, there is a need to identify natural products that can be used as nutraceuticals to prevent and treat early-stage diabetes. White mulberry (Morus alba L.) is a plant that has been used in traditional Chinese medicine for thousands of years due to its many beneficial biological properties. White mulberry leaves are a source of 1-deoxynojirimycin (DNJ), which, due to its ability to inhibit α-glucosidase, can be used to regulate postprandial glucose concentration. In addition to consuming dried white mulberry leaves as herbal tea, many functional foods also contain this raw material. The development of the dietary supplements market brings many scientific and regulatory challenges to the safety, quality and effectiveness of such products containing concentrated amounts of nutraceuticals. In the present study, the quality of 19 products was assessed by determining the content of DNJ, selected (poly)phenols and antioxidant activity (DPPH^• assay). Nine of these products were herbal teas, and the other samples were dietary supplements. These results indicate the low quality of tested dietary supplements, the use of which (due to the low content of nutraceuticals) cannot bring the expected beneficial effects on health. Moreover, a method for determining the content of DNJ (the essential component for antidiabetic activity) based on ATR-FTIR spectroscopy combined with PLS regression has been proposed. This might be an alternative method to the commonly used chromatographic process requiring extraction and derivatization of the sample. It allows for a quick screening assessment of the quality of products containing white mulberry leaves.

Hydroethanolic Extract of Morus nigra L. Leaves: A Dual PPAR-α/γ Agonist with Anti-Inflammatory Properties in Lipopolysaccharide-Stimulated RAW 264.7

Inhibition of systemic inflammation has been a beneficial strategy in treating several non-communicable diseases, which represent one of the major causes of mortality in the world. The Peroxisome Proliferator-Activated Receptors (PPAR) are interesting pharmacological targets, since they can act both through the metabolic and anti-inflammatory pathways. Morus nigra L. has flavonoids in its chemical composition with recognized anti-oxidant activity and often associated with anti-inflammatory activity. Therefore, this study aimed to evaluate the hydroethanolic extract of M. nigra leaves' ability to activate PPAR and promote anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated murine macrophage cells. The leaf extract was prepared by cold maceration, and the chemical profile was obtained by HPLC-DAD. Activation of PPAR α and γ was evaluated by the luciferase reporter assay. The anti-inflammatory activity was assessed by measuring the reactive oxygen species (ROS), nitric oxide (NO), and Tumor Necrosis Factor-α (TNF-α) in RAW 264.7 cells after stimulation with LPS from Escherichia coli. The HPLC-DAD analysis identified two major compounds: rutin and isoquercitrin. The extract showed agonist activity for the two types of PPAR, α and γ, although its major compounds, rutin and isoquercitrin, did not significantly activate the receptors. In addition, the extract significantly reduced the production of ROS, NO, and TNF-α. Treatment with the specific PPAR-α antagonist, GW 6471, was able to partially block the anti-inflammatory effect caused by the extract.

Phytochemical characterization of Morus nigra fruit ultrasound-assisted ethanolic extract for its cardioprotective potential

The current work investigated the phytochemical profile of ultrasound-assisted ethanolic extract of Morus nigra (M. nigra) fruit. FTIR analysis of M. nigra fruit extract revealed the presence of alcohols (O-H), alkanes (C-H stretch), alkenes (C=C), and alkynes (C≡C). The HPLC analysis quantified the quercetin, gallic acid, vanillic acid, chlorogenic acid, syringic acid, cinnamic acid, sinapic acid, and kaempferol. Furthermore, the cardioprotective activity of ethanolic extract of M. nigra fruit was investigated. Cholesterol supplementation (2%) in the daily diet and exposure to cigarette smoke (2 cigarettes twice a day) were to induce hypertension in rats. The experimental animals were categorized into four groups: G0 (negative control), G1 (positive control), G2 (standard drug), and G3 (M. nigra fruit). The fruit extract administration at 300 mg/kg BW/day orally for 2 months significantly (p < .001) enhanced the activities of serum and cardiac tissue antioxidants in hypertensive rats. Meanwhile, the fruit extract reduced the elevated serum lipid profile while significantly increasing the high-density lipoproteins in G3 than G1 and G2. The increase in blood pressure, liver transaminases, and serum lactate dehydrogenase also reduced significantly in M. nigra fruit extract-treated rats. Histopathological findings revealed mild normalization of cardiac myocytes with central nuclei, branching, and cross-striations. Consequently, the M. nigra fruit extract exerted the cardioprotective potential via increasing the antioxidant enzymes and reducing the lipids, lactate dehydrogenase, liver transaminases, and blood pressure. The therapeutic potential of M. nigra fruit can be due to flavonols and phenolic acids. PRACTICAL APPLICATIONS: The present work quantified the Morus nigra fruit phytochemicals and its significant role in reducing lipid markers and blood pressure and improving antioxidant status in rats fed a hypercholesterolemic diet and exposed to cigarette smoke. Conclusively, the inclusion of M. nigra fruit in daily diet could improve the cardiac health of the individuals. Furthermore, the therapeutic potential of M. nigra fruit and its isolated constituents in modulating the gene expression against cardiac problems can explore after clinical trials and standardization in higher animals.

Identification and Antioxidant Capacity of Free and Bound Phenolics in Six Varieties of Mulberry Seeds Using UPLC-ESI-QTOF-MS/MS

Mulberry seeds are a byproduct of juice processing and may be an important resource for its abundant compounds. In this study, we analyzed the qualitative composition of free and bound phenolics from six varieties of mulberry seeds using UPLC-ESI-QTOF-MS/MS. Free phenolics (FPs) and bound phenolics (BPs) were measured using the Folin–Ciocalteu method; antioxidant capacity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, using the ferric reducing antioxidant power assay. A total of 28 free and 11 bound phenolics were extracted and identified, wherein five free phenolics were found in mulberry matrices for the first time. The six varieties of mulberry seeds exhibited higher content of FPs than BPs, and there was a correlation between the phenolic content and antioxidant capacity. Consequently, three varieties were selected for their high phenolic content and antioxidant capacity. This study might offer a theoretical basis for the utilization of mulberry seed.

Combination of mulberry leaf active components possessed synergetic effect on SD rats with diabetic nephropathy by mediating metabolism, Wnt/β-catenin and TGF-β/Smads signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Mulberry leaf has attracted much attention due to its excellent curative effect on diabetes and its complications, whether the combination of its effective components have protective and synergistic effect on diabetic nephropathy (DN) in vivo remain unclear.

AIM OF THE STUDY

The aim of this study was to investigate the protective and synergistic effect of the combination (MAF_1:1 and MAF_1:5) of mulberry leaf alkaloids (MA) and flavonoids extract (MF) on DN.

MATERIALS AND METHODS

A step by step method consisted of network pharmacological prediction, animal in vivo validation and metabolic mechanism research was used to construct the multi-component-target-pathway network of mulberry leaf against DN. Firstly, the potential components and mechanism of mulberry leaf against DN was explored by network pharmacology analysis. Secondly, DN animal model was established to validate the anti-DN activity of these potential compounds. Thirdly, the metabolomics of serum and urine samples from animal experiments was analyzed to explore the anti-DN mechanism of these potential compounds.

RESULTS

The results of network pharmacology demonstrated that a total of 7 compounds detected in MA and MF exhibited anti-DN activity, their mechanism were strongly in connection with metabolic pathways, arachidonic acid metabolism, sphingolipid signaling pathway, etc. The results of animal experiment indicated that MAF_1:1 and MAF_1:5 significantly relieved metabolic disorders through regulating Wnt/β-catenin and TGF-β/Smads signaling pathway, just like MF or MA alone. Metabolomics suggested they could regulate 16 serum and 7 urine endogenous metabolites through arachidonic acid metabolism, phenylalanine metabolism and sphingolipid metabolism, thus alleviated DN. Significantly, MAF_1:1 and MAF_1:5 might possess synergistic effect considering their therapeutic effects on DN rats were superior to the single use of MA or MF.

CONCLUSIONS

MAF_1:1 and MAF_1:5 possessed protective and synergistic effect on DN rats through multi-target and multi-pathways. These findings were of great scientific significance and application value to reveal the advantage of mulberry leaf in preventing and treating DN.

Anticancer and Neuroprotective Activities of Ethyl Acetate Fractions from Morus macroura Miq. Plant Organs with Ultraperformance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry Profiling

Column chromatography afforded the isolation of seven secondary metabolites (1-(2,4,6-trihydroxy phenyl)-ethanone-4-O-β-d-glucopyranoside, naringenin-7-O-β-d-glucopyranoside, kaempferol-3-O-α-l-rhamnoside, kaempferol-3-O-β-d-glucopyranoside, quercetin-3-O-β-d-glucopyranoside, quercetin-3-O-β-d-galactopyranoside, rutin) from the ethyl acetate (ET) fractions of Morus macroura Miq. stems (S), leaves (L), and fruits (F). Their identification based on ultraviolet (UV), electron ionization (EI), electrospray ionization-mass spectrometry (ESI-MS), and 1D and 2D NMR data. In addition, profiling of ET fractions using ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) resulted in the identification of 82 compounds belonging to different classes, mainly polyphenolic constituents. Chemical profiling as well as molecular docking directed us to biological evaluation. Interestingly, the ET-L fraction exhibited a robust cytotoxic activity against HepG-2, MCF-7, and HELA cell lines. Also, it displayed a neuromodulatory activity against cisplatin neurotoxicity in rats by ameliorating the neurobehavioral dysfunction visualized in the open field and Y-maze test and modulating the neurochemical parameters such as brain amino acid levels (glutamate, aspartate, serine, and histidine), oxidative stress markers (GSH, MDA, and 8-hydroxy-2'-deoxyguanosine), and purinergic cell energy (adenosine triphosphate (ATP) and adenosine monophosphate (AMP)). In conclusion, the isolated compounds (kaempferol-3-O-β-glucoside and quercetin-3-O-β-glucoside) from the ET-L fraction could serve as potent anticancer agents due to their strong antioxidant, in vitro cytotoxicity, and in vivo neuroprotective activity.

LC-MS Characterization and Quantification of Known and Unknown (Poly)phenol Metabolites-Possible Pitfalls and Their Avoidance

This review focuses on the LC-MS characterization and quantification of dietary (poly)phenols and their metabolites. It draws attention to errors, omissions, and misunderstandings that appear frequently in published papers, and suggests strategies for their avoidance. Aspects covered include the use of authentic standards and surrogate reference materials, the importance of collecting and archiving Total Ion Current MS data, the limitations of using on-line compilations of accurate mass MS data to assign unknown components when multiple isomers are possible, and the often understated magnitude of person-to-person variation that may significantly impact at population level any potential health benefit.

In vitro bioactivity evaluation of mulberry leaf extracts as nutraceuticals for the management of diabetes mellitus

There is an increasing need for new options to treat diabetes mellitus at its early stage and natural remedies have been recently reassessed as potential candidates owing to their low-cost and effectiveness. Genus Morus plants contain many active compounds with hypoglycaemic, hypolipidemic, and antioxidant effects. Current research on mulberry chemical composition and bioactivity has been generally carried out only on Asian cultivation, where this plant has been traditionally used in the form of leaf infusion for decades. In this work, twelve Italian mulberry cultivars were fully characterised to fill this gap of knowledge, since a strong correlation among composition, genetics and growing area was proven. Antiglycative and hypoglycaemic effects of leaf extracts were evaluated using different in vitro models. The results indicate that the inhibitory effect on carbohydrate digestive enzymes was likely mediated by 1-deoxynojirimycin, kaempferol, quercetin, and chlorogenic acid, acting in a synergistic way. Besides, the combined antiglycative and carbonyl trapping capacities, tested here for the first time, may help in preventing long-term complications related to AGEs in diabetic patients.

The Establishment of Ultrasonic-Assisted Extraction for the Recovery of Phenolic Compounds and Evaluation of Their Antioxidant Activity from Morus alba Leaves

Phenolic compounds of Morus alba leaves are bioactive compounds with beneficial properties for human health. Therefore, in this study, an optimization of ultrasonic assisted extraction by Box–Behnken design was used for the first time to optimize factors such as the percentage of ethanol, ratio solvent/sample (v/w) and extraction time to reach the highest phenolic compound amounts (evaluated by HPLC-MS) while also evaluating in vitro antioxidant activity using DPPH, ABTS and FRAP assays. The optimal extraction conditions were 40% ethanol, 1/400 (w/v) and 35 min. Applying these optimal conditions, which were identified and quantified by HPLC-MS, resulted in the extraction of 21 phenolic compounds. According to these results, the main phenolic compounds in Morus alba leaves are the phenolic glycoside and phenolic acid named protocatechuic acid-glucoside and caffeoylquinic. In addition, Morus alba leaf extract contains flavonols such quercetin-3-O-6-acetylglucoside and rutin, which represent more than 7% of its total phenolic content.

Phytochemical Composition of Different Botanical Parts of Morus Species, Health Benefits and Application in Food Industry

In recent years, mulberry has acquired a special importance due to its phytochemical composition and its beneficial effects on human health, including antioxidant, anticancer, antidiabetic and immunomodulatory effects. Botanical parts of Morus sp. (fruits, leaves, twigs, roots) are considered a rich source of secondary metabolites. The aim of our study was to highlight the phytochemical profile of each of the botanical parts of Morus tree, their health benefits and applications in food industry with an updated review of literature. Black and white mulberries are characterized in terms of predominant phenolic compounds in correlation with their medical applications. In addition to anthocyanins (mainly cyanidin-3-O-glucoside), black mulberry fruits also contain flavonols and phenolic acids. The leaves are a rich source of flavonols, including quercetin and kaempferol in the glycosylated forms and chlorogenic acid as predominant phenolic acids. Mulberry bark roots and twigs are a source of prenylated flavonoids, predominantly morusin. In this context, the exploitation of mulberry in food industry is reviewed in this paper, in terms of developing novel, functional food with multiple health-promoting effects.

Comprehensive characterization of naturally occurring antioxidants from the twigs of mulberry (Morus alba) using on-line high-performance liquid chromatography coupled with chemical detection and high-resolution mass spectrometry

INTRODUCTION

The mulberry tree (Morus alba L.) is a prolific source of biologically active compounds. There is considerable growing interest in probing M. alba twigs as a source of disruptive antioxidant lead candidates for cosmetic skin care product development.

OBJECTIVE

An integrated approach using high-performance liquid chromatography (HPLC) coupled with either chemical detection (CD) or high-resolution mass spectrometry (HRMS) was applied to the hydroalcoholic extract of M. alba to detect and identify lead antioxidant compounds, respectively.

MATERIAL AND METHODS

The twigs were weighed, powdered and homogenized using a mill and the extract was prepared using 70% aqueous ethanol. The antioxidant metabolites were detected with HPLC coupled with CD (based on the ORAC assay) and their structural identification was carried out using a Q-Exactive Orbitrap MS instrument.

RESULTS

Using this approach, 13 peaks were detected as overall contributors to the antioxidant activity of M. alba, i.e. mulberrosides (A & E), oxyresveratrol & its derivatives, moracin & its derivatives and a dihydroxy-octadecadienoic acid, which together accounted for >90% of the antioxidant activity, highlighting the effectiveness of the integrated approach based on HPLC-CD and HPLC-HRMS. Additionally, a (3,4-dimethoxyphenyl-1-O-β-D-apiofuranosyl-(1″ → 6')-O-β-D-glucopyranoside was also discovered for the first time from the twig extract and is presented here.

CONCLUSION

To our knowledge, this is the first report from M. alba twigs using HPLC-CD and HPLC-HRMS that identifies key compounds responsible for the antioxidant property of this native Chinese medicinal plant.

Hepatoprotective effect of different mulberry leaf extracts against acute liver injury in rats by alleviating oxidative stress and inflammatory response

This study investigated the hepatoprotective effect of various mulberry (Morus alba L.) leaf extracts (MLEs), including mulberry ethanol extract (MEE), aqueous extract (MAE) and combination extract (MCE) against D-galactosamine (D-GalN)...

A comprehensive review on the production, pharmacokinetics and health benefits of mulberry leaf iminosugars: Main focus on 1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ

Mulberry leaves are rich in biologically active compounds, including phenolics, polysaccharides, and alkaloids. Mulberry leaf iminosugars (MLIs; a type of polyhydroxylated alkaloids), in particular, have been gaining increasing attention due to their health-promoting effects, including anti-diabetic, anti-obesity, anti-hyperglycemic, anti-hypercholesterolemic, anti-inflammatory, and gut microbiota-modulatory activities. Knowledge regarding the in vivo bioavailability and bioactivity of MLIs are crucial to understand their role and function and human health. Therefore, this review is aimed to comprehensively summarize the existing studies on the oral pharmacokinetics and the physiological significance of selected MLIs (i.e.,1-deoxynojirimycin, d-fagomine, and 2-O-ɑ-d-galactopyranosyl-DNJ). Evidence have suggested that MLIs possess relatively good uptake and safety profiles, which support their prospective use for oral intake; the therapeutic potential of these compounds against metabolic and chronic disorders and the underlying mechanisms behind these effects have also been studied in in vitro and in vivo models. Also discussed are the biosynthetic pathways of MLIs in plants, as well as the agronomic and processing factors that affect their concentration in mulberry leaves-derived products.

Submerged fermentation improves bioactivity of mulberry fruits and leaves

Objective

Mulberry (Morus spp.) fruits and leaves have been proven to possess nutraceutical properties. Due to its fast and easy growing characteristics, mulberry fruits (MF) and leaves (ML) potentially emerge as a great source of functional foods. This study aims to enhance bioactivities (antioxidant, anti-inflammation, and hypoglycemic activity) of MF and ML via submerged fermentation using bacteria (Lactobacillus plantarum TAR 4), yeast (Baker’s yeast and red yeast) and fungi (Tempeh and Tapai starter).

Methods

In this study, 25% (mass to volume ratio) of MF and ML were fermented (48 h) with 1% (mass to volume ratio) of different microbial cultures, respectively. Effects of different fermentations on MF and ML were determined based on the changes of total phenolics (TPC), flavonoids (TFC), anthocyanins, total sugar, DPPH activity, ferric reducing antioxidant power (FRAP), albumin denaturation inhibition activity (ADI), anti-lipoxygenase activity and α-amylase inhibition activity (AI).

Results

Generally, ML had higher AI than MF. However, MF exhibited higher DPPH, FRAP and anti-lipoxygenase activity than ML. After all forms of fermentation, DPPH and AI activity of MF and ML were increased significantly (P < 0.05). However, the effects of fermentation on TPC, FRAP, ADI and anti-lipoxygenase activity of MF were in contrast with ML. TPC, FRAP and anti-lipoxygenase activity of ML were enhanced, but reduced in MF after fermentation. Although the effects exerted by different microorganisms in MF and ML fermentation were different, the bioactivities of MF and ML were generally improved after fermentation. Fermentation by Tempeh starter enhanced TPC (by 2-fold), FRAP (by 2.3-fold), AI (at 10% increment) and anti-lipoxygenase activity (by 5-fold) of ML, whereas Tapai fermentation effectively enhanced the DPPH (at 17% increment) and ADI (by 2-fold) activity of MF.

Conclusion

Findings of this study provide an insight into the future process design of MF and ML processing into novel functional foods.

Effects of enzymatic hydrolysis on physicochemical property and antioxidant activity of mulberry (Morus atropurpurea Roxb.) leaf protein

To improve the antioxidant efficiency of mulberry leaf protein (MLP), alcalase, protamex, papain, flavourzyme, neutrase, and trypsin were used to hydrolyze MLP. The yield of soluble peptides, secondary structures, molecular weight distributions, and antioxidant activities of MLP hydrolysates (MLPHs) were investigated. Results showed that the native MLP was rich in the fraction above 6.5 kDa and was mainly composed of β-sheets, while MLPHs were abundant in the fractions of 0.3-0.6 kDa and 0.6-6.5 kDa and were mainly composed of disordered coils and β-folds. Limited hydrolysis of MLP could lead to better antioxidant activity than extensive hydrolysis. After enzymatic hydrolysis, the content of total sugar and total phenol in MLP increased significantly. MLP hydrolysates prepared with neutrase, alcalase, and protamex were preferable to other enzymes. Meanwhile, an enzyme to substrate level of 1% and a hydrolysis time of 2 hr were the optimum conditions to obtain higher antioxidant hydrolysates using neutrase.

Effects of mulberry leaf silage on antioxidant and immunomodulatory activity and rumen bacterial community of lambs

Background

Rumen is a natural fermentation system and the microorganisms inside can effectively utilize plant bioresource and interact with host metabolism. Here, analysis of rumen microbiome, together with animal performance and serum metabolism in a lamb model were performed to identify the potential use of mulberry leaf silage (MS) to replace alfalfa silage (AS) as a new functional feed resource and to mining the novel specific mulberry leaf associated rumen bacteria interact with host metabolism.

Results

The lambs fed with MS diet showed improved antioxidant capacity and immune function compared to those fed AS diet. The MS diet significantly altered rumen microbiota α- and β-diversity and taxonomic composition. Microbial analysis revealed that Bifidobacterium, Lactobacillus and Schwartzia were enhanced, and Ruminococcaceae UCG-010 and Lachnospiraceae_XPB1014_group were down-regulated in the rumen of MS group. A strong association was also found between these rumen microbial taxa and host antioxidant and immunomodulatory capacity.

Conclusion

These findings indicated that mulberry leaf silage can be a high-quality feed source or bioactive pharmaceutical that is responsible for ruminant’s health benefits. The modified rumen microbial community by mulberry leaf silage were associated with the enhanced antioxidant capacity and immunomodulatory of lambs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02311-1.

Comparison of free and bound phenolic compositions and antioxidant activities of leaves from different mulberry varieties

Mulberry leaves are used in traditional Chinese medicine and contain numerous active substances that are known to be beneficial for human health. The aim of this study was to investigate the phenolic compositions and antioxidant activities of the leaves from 23 mulberry cultivars. Qualitative LC-ESI-QTOF analysis revealed the presence of 11 phenolic compounds in the free phenolic extracts and 10 phenolic compounds in the bound fractions. Chlorogenic acid and caffeic acid were the major components in the free and bound fractions, respectively. The results revealed that the changguosang cultivar from Taiwan contained the greatest content of phenolic compounds as well as the highest antioxidant activity among the 23 cultivars examined, as determined using three separate antioxidant assays. The isoquercitrin, chlorogenic acid, and rutin contents of the free phenolic extracts displayed significant correlations with the antioxidant activities, while syringic acid and rutin were the main contributors to the antioxidant activities of the bound phenolic fractions. The obtained results demonstrate that mulberry leaves contain a variety of beneficial phenolic substances and may be suitable for further development as a herbal medicine.

Morus alba L. Plant: Bioactive Compounds and Potential as a Functional Food Ingredient

Morus alba L. (M. alba) is a highly adaptable plant that is extensively incorporated in many traditional and Ayurveda medications. Various parts of the plant, such as leaves, fruits, and seeds, possess nutritional and medicinal value. M. alba has abundant phytochemicals, including phenolic acids, flavonoids, flavonols, anthocyanins, macronutrients, vitamins, minerals, and volatile aromatic compounds, indicating its excellent pharmacological abilities. M. alba also contains high nutraceutical values for protein, carbohydrates, fiber, organic acids, vitamins, and minerals, as well as a low lipid value. However, despite its excellent biological properties and nutritional value, M. alba has not been fully considered as a potential functional food ingredient. Therefore, this review reports on the nutrients and bioactive compounds available in M. alba leaves, fruit, and seeds; its nutraceutical properties, functional properties as an ingredient in foodstuffs, and a microencapsulation technique to enhance polyphenol stability. Finally, as scaling up to a bigger production plant is needed to accommodate industrial demand, the study and limitation on an M. alba upscaling process is reviewed.

The Effects of Morus alba L. Fortification on the Quality, Functional Properties and Sensory Attributes of Bread Stored under Refrigerated Conditions

Mulberry is one of the most beneficial plant of our planet for sustainable development. White mulberry (Morus alba L.) is widely recognized for its health-promoting properties. It is characterized by a high content of bioactive compounds, mainly flavonoids, and has a strong antioxidant effect, and thus can have a beneficial effect on health. The aim of the study was to evaluate the effect of freezing storage of bread with the addition of extract from mulberry leaves and fruits on the content of polyphenols, antioxidant activity and sensory properties. The stored bread with mulberry addition was characterized by high content of phenolic compounds, reducing and chelating activity and antiradical activity. The addition of mulberry had greater effect on the increase in the content of protocatechuic and chlorogenic acids, and isoquercetin among the flavonols. Bread enriched with mulberry was microbiologically clean and sensory accepted both after baking and after 30 days of storage under refrigerated conditions. White mulberry is a raw material which can be used as an addition to enrich refrigerated bread. The use of the extract and mulberry fruit to fortify bread is consistent with the principle of sustainable development due to the use of raw materials which are a good source of compounds contributing to the improvement of the well-being of the population.

Novel Protein Tyrosine Phosphatase 1B Inhibitor-Geranylated Flavonoid from Mulberry Leaves Ameliorates Insulin Resistance

Mulberry leaf is a common vegetable with a variety of beneficial effects, such as hypoglycemic activity. However, the underlying mechanism of its hypoglycemic effect have not been fully revealed. In this study, two flavonoid derivatives were isolated from mulberry leaves, a new geranylated flavonoid compound (1) and its structural analogue (2). The structures of compounds 1 and 2 were elucidated using spectroscopic analysis. To study the potential hypoglycemic properties of these compounds, their regulatory effects on protein tyrosine phosphatase 1B (PTP1B) were investigated. In comparison to oleanolic acid, compounds 1 and 2 showed significant inhibitory activities (IC₅₀ = 4.53 ± 0.31 and 10.53 ± 1.76 μM) against PTP1B, the positive control (IC₅₀ = 7.94 ± 0.76 μM). Molecular docking predicted the binding sites of compound 1 to PTP1B. In insulin-resistance HepG2 cell, compound 1 promoted glucose consumption in a dose-dependent manner. Furthermore, western blot and polymerase chain reaction analyses indicated that compound 1 might regulate glucose consumption through the PTP1B/IRS/PI3K/AKT pathway. In conclusion, geranylated flavonoids in mulberry leaves inhibite PTP1B and increase the glucose consumption in insulin-resistant cells. These findings provide an important basis for the use of mulberry leaf flavonoids as a dietary supplement to regulate glucose metabolism.

Functional Properties and Antioxidant Activity of Morus alba L. Leaves var. Zolwinska Wielkolistna (WML-P)-The Effect of Controlled Conditioning Process

This study evaluated the effect of adding a new step, termed conditioning, to the traditional processing of leaves from Morus alba var. zolwinska wielkolistna grown in Poland (WML-P). This step, modeled on tea leaves processing, was conducted in a controlled environment on a semi-technical scale. The primary goal was to evaluate the effect of the WML-P conditioning for 1–4 h at 32–35 °C on the content of bioactive compounds (total phenolics, phenolic acids, flavonols, 1-deoxynojirimycin) and antioxidant activity (radical scavenging against DPPH, antioxidant capacity, chelating activity and ferric reducing antioxidant potential) of the lyophilized extracts. For the first time WML-P extracts content was comprehensively characterized by assessing dietary fiber fractions, fatty acids, amino acids, macro- and microelements and chlorophyll content. Compared to the traditional process, adding the conditioning step to WML-P processing resulted in an increased total phenolics content, radical scavenging capacity, ability to quench 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) and iron-chelating ability in the lyophilized extracts. The beneficial effect depended on conditioning time. The highest flavonols and phenolic acids content were found after 2-h conditioning. We concluded that adding a 2-h conditioning step to traditional WML-P processing results in getting WML-P lyophilized extract with increased bioactive compounds content and high antioxidant activity.

Anti-Inflammatory Effects of Neochlorogenic Acid Extract from Mulberry Leaf (Morus alba L.) Against LPS-Stimulated Inflammatory Response through Mediating the AMPK/Nrf2 Signaling Pathway in A549 Cells

Neochlorogenic acid (nCGA) is a phenolic compound isolated from mulberry leaf (Morus alba L.), which possesses multiple pharmacological activities containing antioxidant and anti-inflammatory effects. However, the role of nCGA in the treatment of acute pneumonia and the underlying molecular mechanism are still unclear. Hence, the aim of study is to investigate the anti-inflammatory properties of nCGA on LPS-stimulated inflammation in A549 cells. In the present study, results reported that nCGA without cytotoxicity significantly reduced the production of TNF-α, IL-6, and NO, and further suppressed the proteins of iNOS, COX2, TNF-α, IL-6 expression. Furthermore, nCGA also inhibited NF-κB activation and blocked MAPKs signaling pathway phosphorylation. In addition, we found nCGA significantly increased the expression of HO-1 via activating the AMPK/Nrf2 signaling pathway to attenuate the inflammatory response, whereas this protective effect of nCGA was reversed by pre-treatment with compound C (C.C, an AMPK inhibitor). Therefore, all these results indicated that nCGA might act as a natural anti-inflammatory agent for the treatment of acute pneumonia.

Antioxidant evaluation-guided chemical profiling and structure-activity analysis of leaf extracts from five trees in Broussonetia and Morus (Moraceae)

Morus and Broussonetia trees are widely used as food and/or feed. Among 23 phenolics identified from leaves of five Moraceae species using UPLC–QTOF–MS/MS, 15 were screened using DPPH/ABTS-guided HPLCs, including seven weak (flavonoids with one hydroxyl on B-ring) and eight strong (four caffeoylquinic acids and four flavonoids, each with a double hydroxyl on B-ring) antioxidants. We then determined the activity and synergistic effects of individual antioxidants and a mixture of the eight strongest antioxidants using DPPH-guided HPLC. Our findings revealed that (1) flavonoid glucuronide may have a more negative effect on antioxidant activity than glucoside, and (2) other compounds in the mixture may exert a negative synergistic effect on antioxidant activity of the four flavonoids with B-ring double hydroxyls but not the four caffeoylquinic acids. In conclusion, the eight phenolics with the strongest antioxidant ability reliably represented the bioactivity of the five extracts examined in this study. Moreover, the Morus alba hybrid had more phenolic biosynthesis machinery than its cross-parent M. alba, whereas the Broussonetia papyrifera hybrid had significantly less phenolic machinery than B. papyrifera. This difference is probably the main reason for livestock preference for the hybrid of B. papyrifera over B. papyrifera in feed.

Roots and Leaf Extracts of Dipsacus fullonum L. and Their Biological Activities

The aim of the study was to identify and evaluate the content of iridoids and phenolic compounds in the leaves and roots of Dipsacus fullonum L. They were identified and quantified by UPLC-PDA-MS/MS. Five iridoid compounds (loganic acid, loganin, sweroside, cantleyoside, and sylvestroside III) were identified in Dipsacus fullonum L. leaves and roots. Seven phenolic acids and three flavones were identified in the leaves, and seven phenolic acids were detected in the roots. The leaves contained more iridoids and phenolic compounds than the roots. We also evaluated the antimicrobial (anti-bacterial and anti-yeast), antioxidant (ORAC methods), and antiacetylcholinesterase (AChE) activities of Dipsacus fullonum L. leaves and roots. Leaf extract demonstrated the strongest antioxidant activity, but roots showed stronger antiacetylcholinesterase activity than leaves. The study also confirmed antibacterial activity of root-derived compounds against Staphylococcus aureus DSM 799 and Escherichia coli ATCC 10536.

Development and evaluation of an automated multi-channel multiplug filtration cleanup device for pesticide residue analysis on mulberry leaves and processed tea

An automated multi-channel multiplug filtration cleanup (m-PFC) device was designed and developed. m-PFC columns were suitably installed in the device. The cycle times, speed and nitrogen pressure parameters of the m-PFC column were optimized. The device was utilized to analyze the 82 pesticide residues in fresh mulberry leaves and processed tea with GC-MS/MS detection. Method validation was performed on 82 pesticide residues in fresh mulberry leaves and processed tea at spiked levels of 0.01, 0.05 and 0.5 mg kg⁻¹. The fortified recoveries of 82 pesticides were 72–115% and the relative standard deviations were 1–15%, except for diniconazole and clodinafop-propargyl in mulberry leaves. The automated multi-channel m-PFC device was successfully applied to detect the pesticide residues in fresh mulberry leaves and processed tea samples. With comparison to the conventional QuEChERS method, the current method using this device did not need additional vortex or centrifugation steps, and could process 48–64 samples in about one hour. The automated m-PFC method saved labor and improved the precision and was shown to be efficient and practical in pesticide residue analysis.

An automated device based on QuEChERS cleanup was developed, which is simple, fully automated, highly precise and highly efficient.

Identification of Bioactive Phytochemicals in Mulberries

Mulberries are consumed either freshly or as processed fruits and are traditionally used to tackle several diseases, especially type II diabetes. Here, we investigated the metabolite compositions of ripe fruits of both white (Morus alba) and black (Morus nigra) mulberries, using reversed-phase HPLC coupled to high resolution mass spectrometry (LC-MS), and related these to their in vitro antioxidant and α-glucosidase inhibitory activities. Based on accurate masses, fragmentation data, UV/Vis light absorbance spectra and retention times, 35 metabolites, mainly comprising phenolic compounds and amino sugar acids, were identified. While the antioxidant activity was highest in M. nigra, the α-glucosidase inhibitory activities were similar between species. Both bioactivities were mostly resistant to in vitro gastrointestinal digestion. To identify the bioactive compounds, we combined LC-MS with 96-well-format fractionation followed by testing the individual fractions for α-glucosidase inhibition, while compounds responsible for the antioxidant activity were identified using HPLC with an online antioxidant detection system. We thus determined iminosugars and phenolic compounds in both M. alba and M. nigra, and anthocyanins in M. nigra as being the key α-glucosidase inhibitors, while anthocyanins in M. nigra and both phenylpropanoids and flavonols in M. alba were identified as key antioxidants in their ripe berries.

Randomized double-blind placebo-controlled trial of the effect of Morus nigra L. (black mulberry) leaf powder on symptoms and quality of life among climacteric women

OBJECTIVE

To test the efficacy of Morus nigra L. (MN) leaf powder for treating climacteric symptoms by comparison with hormone therapy (HT) and placebo.

METHODS

A randomized controlled trial among 62 climacteric women attending Hospital of the Federal University of Maranhão, Brazil. Women were divided into MN, HT, and placebo groups, and received 250 mg of MN leaf powder, 1 mg of estradiol, or placebo for 60 days. Primary outcomes were the Blatt-Kupperman index (BKI) for climacteric symptoms and SF-36 health questionnaire scores.

RESULTS

Baseline sociodemographic variables, BKI scores, symptoms, and SF-36 domains did not differ among the groups. There was a reduction in mean BKI in the MN (17.5 vs 9.7, P<0.001), HT (15.4 vs 8.6, P=0.001), and placebo (16.1 vs 12.4, P=0.040) groups. Analysis of quality of life (QoL) showed that functional capacity (P=0.006), vitality (P=0.031), mental health (P=0.017), and social aspect (P<0.01) improved after treatment in the MN group. The HT group showed improvement in emotional limitation (P=0.040), and the placebo group showed better functional capacity (P=0.030) after treatment.

CONCLUSIONS

Climacteric symptoms and QoL improved after administration of 250 mg of MN leaf powder for 60 days, similar to the effects of HT. The trial is registered in the Brazilian Registry of Clinical Trials (REBEC) under registration number RBR-9t4xxk.