Polyhydroxylated alkaloids isolated from mulberry trees (Morusalba L.) and silkworms (Bombyx mori L.)

Intestinal Absorption and Tissue Distribution of Aza-Sugars from Mulberry Leaves and Evaluation of Their Transport by Sugar Transporters

Mulberry leaves are rich in aza-sugars, particularly 1-deoxynojirimycin (DNJ), fagomine, and 2-O-α-d-galactopyranosyl-1-deoxynojirimycin (GAL-DNJ), which have antidiabetes and antiobesity properties. To help us understand the mechanisms of action of aza-sugars, pharmacokinetic studies are necessary. Therefore, in this study, we evaluated and compared the absorption and organ distribution of these aza-sugars in rats. Following oral intake, DNJ exhibited the highest plasma concentration followed by fagomine and GAL-DNJ. Meanwhile, similar amounts of DNJ and fagomine were present in organs, while GAL-DNJ was hardly detected, suggesting the diversity in absorption and distribution characteristics of these aza-sugars. We then investigated the role of the sodium-glucose cotransporter and the glucose transporter (GLUT) in the transport of aza-sugars and found that both are involved in DNJ transport, while transport of fagomine is solely facilitated by the GLUT. These findings provide insight into the bioavailability and bioactive mechanisms of these aza-sugars.

Flavonoids from Mulberry Leaves Alleviate Lipid Dysmetabolism in High Fat Diet-Fed Mice: Involvement of Gut Microbiota

Here, we investigated the roles and mechanisms of flavonoids from mulberry leaves (FML) on lipid metabolism in high fat diet (HFD)-fed mice. ICR mice were fed either a control diet (Con) or HFD with or without FML (240 mg/kg/day) by oral gavage for six weeks. FML administration improved lipid accumulation, alleviated liver steatosis and the whitening of brown adipose tissue, and improved gut microbiota composition in HFD-fed mice. Microbiota transplantation from FML-treated mice alleviated HFD-induced lipid metabolic disorders. Moreover, FML administration restored the production of acetic acid in HFD-fed mice. Correlation analysis identified a significant correlation between the relative abundances of Bacteroidetes and the production of acetic acid, and between the production of acetic acid and the weight of selected adipose tissues. Overall, our results demonstrated that in HFD-fed mice, the lipid metabolism improvement induced by FML administration might be mediated by gut microbiota, especially Bacteroidetes-triggered acetic acid production.

A common strategy towards the synthesis of 1,4-dideoxy-1,4-imino-l-xylitol, deacetyl (+)-anisomycin and amino-substituted piperidine iminosugars

A strategy towards the synthesis of three different target molecules, namely 1,4-dideoxy-1,4-imino-l-xylitol, deacetyl (+)-anisomycin and amino-substituted piperidine iminosugars, molecules of potential biological and medicinal significance, is reported from a common amino-vicinal diol intermediate derived from tri-O-benzyl-d-glucal. Construction of the key pyrrolidine ring present in 1,4-dideoxy-1,4-imino-l-xylitol and (+)-anisomycin was a consequence of thermodynamically driven concomitant intramolecular nucleophilic addition reaction of the amino group to the resultant aldehyde obtained by oxidative cleavage of the amino-vicinal diol. Alternatively, double nucleophilic substitution on an amino-diol, after mesylation, with various amines delivered amino-substituted piperidine iminosugars in good yields.

Anti-diabetic potential of plant alkaloids: Revisiting current findings and future perspectives

Diabetes mellitus (DM) is a chronic metabolic disease which causes millions of death all over the world each year, and its incidence is on increase. The most prevalent form, type 2 DM, is characterized by insulin resistance and β-cell dysfunction, whereas type 1 DM is due to insulin deficiency as a result of β-cell destruction. Various classes of synthetic drugs have been developed to regulate glucose homeostasis and combat the development of late-diabetic complications. However, several of these chemical agents are either sub-optimal in their effect and/or may have side effects. Biologically, alkaloids unveiled a wide range of therapeutic effects including anti-diabetic properties. The chemical backbones of these compounds have the potential to interact with a wide range of proteins involved in glucose homeostasis, and thus they have received increasing attention as reliable candidates for drug development. This review sets out to investigate the anti-diabetic potential of plant alkaloids (PAs), and therefore, scientific databases were comprehensively screened to highlight the biological activity of 78 PAs with a considerable anti-diabetic profile. There are not enough clinical data available for these phytochemicals to follow their fingerprint in human, but current studies generally recommending PAs as potent α-glucosidase inhibitors. Except for some classes of monoterpene alkaloids, other compounds showed similar features as well as the presently available anti-diabetic drugs such as amino sugars and other relevant drugs. Moreover, the evidence suggests that PAs have the potential to be used as alternative additives for the treatment of DM, however, further in vitro and in vivo studies are needed to validate these findings.

Multiple In vitro biological effects of phenolic compounds from Morus alba root bark

ETHNOPHARMACOLOGICAL RELEVANCE

Morus alba L. is used in traditional Chinese medicine for the treatment of various diseases, including bacterial infections and inflammation. As a rich source of phenolic compounds, the plant is an object of many phytochemical and pharmacological studies.

AIM OF THE STUDY

The aim of the study was to isolate and evaluate possible parallel antiviral, antibacterial, and anti-inflammatory activities of phenolic mulberry compounds.

MATERIALS AND METHODS

Extensive chromatographic separation of mulberry root bark extract and in vitro biological screening of 26 constituents identified promising candidates for further pharmacological research. Selected compounds were screened for anti-infective and anti-inflammatory activities. Antiviral activity was determined by the plaque number reduction assay and by the titer reduction assay, antibacterial using broth microdilution method, and anti-inflammatory activity using COX Colorimetric inhibitor screening assay kit. One compound was evaluated in vivo in carrageenan-induced paw-edema in mice.

RESULTS

Five prenylated compounds 1, 2, 8, 9, and 11, together with a simple phenolic ester 13, exhibited inhibitory activity against the replication of herpes simplex virus 1 (HSV-1) or herpes simplex virus 2 (HSV-2), with IC₅₀ values ranging from 0.64 to 1.93 μg/mL, and EC₅₀ values 0.93 and 1.61 μg/mL. Molecular docking studies demonstrated the effects of the active compounds by targeting HSV-1 DNA polymerase and HSV-2 protease. In antibacterial assay, compounds 1, 4, 11, and 17 diminished the growth of all of the Gram-positive strains tested, with MIC values of 1-16 μg/mL. The anti-inflammatory ability of several compounds to inhibit cyclooxygenase 2 (COX-2) was tested in vitro, and compound 16 displayed greater activity than the indomethacin, positive control. Mulberrofuran B (11) showed anti-inflammatory activity in vivo against carrageenan-induced paw-edema in mice.

CONCLUSIONS

Experimental investigation showed promising antiviral, antibacterial, and/or anti-inflammatory activities of the phenolic mulberry constituents, often with multiple inhibitory effects that might be used as a potential source of new medicine.

iTRAQ-Based Quantitative Proteomic Analysis of Digestive Juice across the First 48 Hours of the Fifth Instar in Silkworm Larvae

The silkworm is an oligophagous insect for which mulberry leaves are the sole diet. The nutrients needed for vital activities of the egg, pupal, and adult stages, and the proteins formed in the cocoon, are all derived from the larval stages. The silkworm feeds and grows quickly during the larval stages. In particular, the amount of leaf ingested and digested quickly increases from the ecdysis to the gluttonous stage in the fifth instar period. In this study, we used the iTRAQ proteomic technique to identify and analyze silkworm larval digestive juice proteins during this period. A total of 227 proteins were successfully identified. These were primarily serine protease activity, esterase activity, binding, and serine protease inhibitors, which were mainly involved in the digestion and overcoming the detrimental effects of mulberry leaves. Moreover, 30 genes of the identified proteins were expressed specifically in the midgut. Temporal proteomic analysis of digestive juice revealed developmental dynamic features related to molecular mechanisms of the principal functions of digesting, resisting pathogens, and overruling the inhibitory effects of mulberry leaves protease inhibitors (PIs) with a dynamic strategy, although overruling the inhibitory effects has not yet been confirmed by previous study. These findings will help address the potential functions of digestive juice in silkworm larvae.

Assessment of mulberry leaf as a potential feed supplement for animal feeding in P.R. China

OBJECTIVE

Mulberry (Morus alba L.) is a cultivated shrub grown widely in the sub-tropical and tropical areas. It has been shown that mulberry leaf contains high levels of protein while having polyphenols as phytonutrients. Therefore, it is important to conduct an experiment to assess potential toxic level from mulberry on behavior, blood hematological and coagulation parameter using Sprague-Dawley (SD) rats.

METHODS

Both male and female SD rats were given an intragastric administration of respective treatments of mulberry leaf intakes (control, low and high levels). Parameters of feed intake, hematological and coagulation of blood parameters, as well as liveweight changes were taken during the 7 d of adaptation, 28 d of treatment exposure, and 14 d of recovery periods, respectively. All treatment data were statistically analyzed using analysis of variance of SPSS17.0 for Windows Statistical Software following the Randomized complete block design with sex as a block.

RESULTS

Most of the parameters of the physical symptoms of the SD rats, were not significantly different (p>0.05) when compared with that of the control group. Those which remain unchanged in each dose group were, body weight (BW) gain, feed intake, the hematology and coagulation indexes. Although, there were a few individual indicators that were abnormal, but the overall physiological appearance of the rats were normal.

CONCLUSION

Results under this experiment revealed that most hematological and coagulation parameters of the SD rats in both male and female were normal, although the weight gain of female rats in high-dose group was significantly reduced than those of the male rats. Under this study, the use of mulberry leaf up to 2 g/kg BW did not result in abnormal phenomenon in the SD rats. These findings would offer useful information for further in vivo feeding trials in animals to extensively use of mulberry leaf to improve animal production, particularly in P.R. China.

Nutraceutical Properties of Mulberries Grown in Southern Italy (Apulia)

In this work, for the first time, were analyzed mulberry genotypes grown in Apulia (Southern Italy, Salento region) were analyzed. Two local varieties of Morus alba (cv. Legittimo nero and cv. Nello) and one of Morus nigra were characterized for content in simple sugars, organic acids, phenols, anthocyanins; fruit antioxidant activity (AA) was also evaluated by three different methods (2,2-Diphenyl-1-picrylhydrazyl, DPPH; 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS; and Ferric reducing antioxidant potential, FRAP test). The results showed that the sugars amount ranged between 6.29 and 7.66 g/100 g fresh weight (FW) while the malic and citric acids content was low, at about 0.1–1 g/100 g FW. Mulberries are a good source of phenols which are present in higher values in M. nigra and M. alba cv. Legittimo nero (485 and 424 mg Gallic Acid Equivalent (GAE)/ 100 g FW, respectively). The high performance liquid chromatography/diode array detector/mass spectrometry (HPLC/DAD/MS) analysis identified 5 main anthocyanin compounds present in different concentrations in each variety of mulberry: cyanidin 3-sophoroside, cyanidin 3-glucoside, cyanidin 3-rutinoside, pelargonidin 3-glucoside, pelargonidin 3-rutinoside. The highest concentration of anthocyanins was determined in Morus alba Legittimo (about 300 mg/100 g FW) while the lowest content (about 25 mg/100 g FW) was measured in M. alba cv. Nello. Morus nigra showed a good AA in comparison with the different M. alba genotypes with all the used methods; its AA was equal to 33, 26 and 21 μmols Trolox/g FW when using DPPH, ABTS and FRAP tests, respectively. All genotypes showed an anti-inflammatory activity (measured by cyclooxygenase (COX) inhibitory assay) which was also compared with two commercial anti-inflammatory drugs. The data obtained support the high biological qualities of mulberry fruits and their diffusion in human nutrition.

Morus alba (mulberry), a natural potent compound in management of obesity

Obesity is defined as body mass index, higher than 30 kg/m², which are associated with diverse diseases including type 2 diabetes, hypertension, coronary diseases, certain cancers, osteoarthritis and dyslipidemia. The subject of this review article was to evaluate the potency of Morus alba or "mulberry" as natural potent anti-obesity agent in management of obesity. For writing this manuscript, we searched in all accessible international databases, electronic resources (PubMed, Science Direct, Springer, Wiley and Google), unpublished data (R&D reports, thesis and dissertation). The inhibitory effects of mulberry on digestive enzymes and adipocyte differentiation, and its stimulatory effects on energy expenditures, and lipid metabolism are responsible mechanisms for management of obesity in obese patients. Furthermore, the results of these preclinical studies and its related mechanisms should be evaluated in large clinical trials.

Chiral separation, absolute configuration, and bioactivity of two pairs of flavonoid enantiomers from Morus nigra

An undescribed isoprenylated flavonol racemate, nigranol C, with an unprecedented 7/6/6 ring system, was isolated from the twigs of Morus nigra L. The structure was assigned through a comprehensive analysis of HRMS, IR, and NMR data. Chiral separation of nigranol C was successfully carried out to yield a pair of enantiomers, nigranol C-a and nigranol C-b, whose absolute configurations were determined by ECD calculation. A plausible biogenetic pathway for nigranol C was proposed. A previously isolated sanggenon-type flavonone racemate, nigragenon E, was also well resolved by chiral HPLC to offer another pair of enantiomers, nigragenon E-a and nigragenon E-b, whose stereo configurations were determined by ECD data. All of the isolated compounds showed prominent α-glucosidase inhibitory activities with IC₅₀ values ranging from 9.79 to 30.21 μM, while only the sanggenon-type flavonones exhibited tyrosinase inhibitory effects comparable to that of the positive control, kojic acid, the IC₅₀ value of which was 27.14 μM. In addition, it was found that the stereo configurations of these compounds seemed to play a negligible role in their inhibitory activities towards the two enzymes.

Protective effect of mulberry crude extract against nonylphenol-induced thyroid disruption by inhibiting the activity of deiodinase in rats

Nonylphenol (NP) is an endocrine-disrupting chemical (EDC) that can lead to thyroid disruption. We explored NP-induced toxicity in the rat thyroid and evaluated the mitigating effects of mulberry crude extract (MCE) on NP toxicity. First, we aimed to evaluate NP-induced thyroid disruption by dosing Sprague-Dawley (SD) rats with NP (0, 30, 90, or 270 mg/kg body weight) daily for 28 days. Second, we aimed to determine whether MCE had a detoxifying effect on NP-induced thyroid disruption by dosing SD rats with NP (270 mg/kg body weight) or/and MCE (30, 60, or 120 mg/kg body weight) daily for 28 days. We found that NP significantly inhibited free triiodothyronin (FT₃) and free thyroxine (FT₄) activity in rat serum (P < 0.05), but MCE intervention significantly increased FT₃ and FT₄ serum levels (P < 0.05). It is possible that changes in hormonal composition might trigger the TRH-TSH-TH automatic feedback loop. The activity of the three iodothyronine deiodinases increased significantly after NP-dosing (P < 0.05), but only deiodinase3 (D3) was downregulated after MCE treatment (P < 0.05). Therefore, MCE might be an effective NP-detoxification agent against thyroid disruption because it regulates D3 activity.

Transcriptomic analysis of key genes involved in chlorogenic acid biosynthetic pathway and characterization of MaHCT from Morus alba L

Mulberry leaves (Morus alba L.) are of high medicinal value in traditional Chinese medicine with chlorogenic acid (CGA) as its major biologically active constituent. Mulberry leaves require that they be harvested after frost; previous studies have shown CGA accumulation significantly increased after frost. However, the molecular mechanism of how frost changes the CGA content in mulberry leaves is unclear. Additionally, the mechanism of CGA biosynthesis and key genes in mulberry leaves are not well-understood. In this study, transcriptome sequencing was performed on two mulberry leaf samples with different CGA contents (before and after frost). Fifty-eight genes were annotated in the CGA biosynthetic pathway. Compared to those in pre-frost mulberry leaves, 12 and 5 genes were upregulated and downregulated, respectively, in post-frost leaves. Correlation analysis showed that the expression levels of four genes were significantly positively correlated with CGA content, including those encoding phenylalanine ammonia-lyase, 4-coumarate-CoA ligase, hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyltransferase (HCT), and coumaroyl quinate/shikimate 3'-hydroxylase, and may be key genes in the CGA biosynthetic pathway. We cloned MaHCT4 (GenBank accession no. MH476577) from mulberry leaves. Multiple sequence alignment suggested that MaHCT4 contains the conserved domains HXXXD and DFGWG. Enzymatic assays indicated that MaHCT4 catalyzes the formation of p-coumaroyl shikimic acid, p-coumaroyl quinic acid, and CGA. The K_m values of quinic acid and shikimic acid were 10 ± 1.0 and 31 ± 1.7 μM, respectively, suggesting that MaHCT4 favored quinic acid over shikimic acid as its acyl acceptor. Using quinic acid as an acyl acceptor, MaHCT4 showed a preference for p-coumaroyl-CoA over caffeoyl-CoA. Our results provide insight into the molecular mechanism of how frost alters the CGA content and roles of key genes involved in the CGA biosynthetic pathway in mulberry leaves.

A Systematic Review of the Medicinal Potential of Mulberry in Treating Diabetes Mellitus

Diabetes mellitus (DM) is a serious metabolic disorder which has reached epidemic proportions all over the world. Despite tremendous developments in medicinal chemistry, traditional medicine is still commonly used for the prevention and treatment of DM. Traditional herbal medicines have played a major role in the management of DM in Asian countries. In particular, mulberry has commonly been utilized in China for the treatment of DM for thousands of years. In the last decade, numerous preclinical findings have suggested that mulberry is a promising therapeutic agent for the treatment of DM, and the polyhydroxylated alkaloids, flavonoids and polysaccharides from mulberry may be the potential active components. The present review systematically summarizes the chemical composition of mulberry and the pharmacological effects of different medicinal parts on DM; these effects include influences on glucose absorption, insulin (INS) production/secretion, anti-oxidation and anti-inflammation processes. After summarizing our research findings, we will discuss the challenges and opportunities and explore the direction of future research and the potential for developing mulberry into pharmaceuticals for the widespread treatment of DM.

Microbial oil production from solid-state fermentation by a newly isolated oleaginous fungus, Mucor circinelloides Q531 from mulberry branches

In this study, a newly isolated oleaginous fungus, Mucor circinelloides (M. circinelloides) Q531, was able to convert mulberry branches into lipids. The highest yield and the maximum lipid content produced by the fungal cells were 42.43 ± 4.01 mg per gram dry substrate (gds) and 28.8 ± 2.85%, respectively. The main components of lignocellulosic biomass were gradually reduced during solid-state fermentation (SSF). Cellulose, hemicellulose and lignin were decreased from 45.11, 31.39 and 17.36% to 41.48, 28.71, and 15.1%, respectively. Gas chromatography analysis showed that the major compositions of the fermented products were palmitic acid (C16:0, 18.42%), palmitoleic acid (C16:1, 5.56%), stearic acid (C18:0, 5.87%), oleic acid (C18:1, 33.89%), linoleic acid (C18:2, 14.45%) and γ-linolenic acid (C18:3 n6, 22.53%) after 2 days of SSF. The fatty acid methyl esters contained unsaturated fatty acids with a ratio of 75.95%. The composition and content obtained in this study are more advantageous than those of many other biomass lipids. Meanwhile, the oleaginous fungus had a high cellulase activity of 1.39 ± 0.09 FPU gds^-1. The results indicate that the enzyme activity of the isolated fungus was capable of converting the cellulose and hemicelluloses to available sugar monomers which are beneficial for the production of lipids.

Partial-least-squares and canonical-correlation analysis of chemical constituents and active ingredients of new types of Chinese mulberries

OBJECTIVE

To investigate the correlation between chemical constituents and active ingredients of 13 types of Chinese mulberry fruits.

METHODS

Thirteen types mulberry fruits were harvested. The correlation between chemical constituents and active ingredients (primarily anthocyanins and rutins) of 13 new types of Chinese mulberries was assessed using partial-least-squares, principle-component and canonical-correlation analyses.

RESULTS

Vitamin C and titratable acid in the mulberry fruits were critical components that affected the active ingredients, especially anthocyanins and rutins. The content of titratable acid content was related to the fruit flavor and maintained the balance of anthocyanins, vitamin C and rutins. Mineral elements, such as Zn and Cu, also played a vital role in these processes. Low contents of sugar, crude protein, crude fat and pectin were significantly correlated with the mineral elements.

CONCLUSION

Chemical constituents and mineral elements can mutually affect the concentration. It provides a novel method for any changes in the quality of new types of Chinese mulberries, which can identify the sources of new types of natural antioxidants.

The Chemical Synthesis and Applications of Tropane Alkaloids

Tropanes are an important class of alkaloid natural products that are found in plants all over the world. These compounds can exhibit significant biological activity and are among the oldest known medicines. In the early 19th century, tropanes were isolated, characterized, and synthesized by notable chemical researchers. Their significant biological activities have inspired tremendous research efforts toward their synthesis and the elucidation of their pharmacological activity both in academia and in industry. In this chapter, which addresses the developments in this field since 1994, the focus is on the synthesis of these compounds, and several examples of sophisticated synthetic protocols involving both asymmetric and catalytic approaches are described. In addition, the structures of more than 100 new alkaloids are included as well as the applications and pharmacological properties of some tropane alkaloids.

Mulberry leaf extract reduces the glycemic indexes of four common dietary carbohydrates

BACKGROUND

1-Deoxynojirimycin (DNJ), a component of mulberry leaf extract (MLE), reduces postprandial hyperglycemia by inhibiting intestinal a-glycosidase. The aim of this exploratory study was to investigate the effects of MLE on the glycemic indexes (GI) of common dietary carbohydrates.

METHODS

This single-center, randomized, open-label, 7-cycle self-controlled crossover study enrolled 15 healthy volunteers at the National Drug Clinical Trial Institution, Second Affiliated Hospital of Tianjin University of Traditional Chinese Medicine (June 2014 to December 2014). The participants were randomized to receive glucose (3 occasions), glucose+MLE, sucrose+MLE, maltose+MLE, and maltodextrin+MLE orally during 7 visits (every 3 days). Blood glucose level was tested at 15 minutes before and at 15, 30, 45, 60, 90, and 120 minutes after carbohydrate intake. The GI of each carbohydrate relative to glucose (GI = 100) was calculated using the incremental area under the curve method. Safety was assessed at each visit.

RESULTS

All participants completed the protocol. After carbohydrate ingestion, blood glucose level peaked at 30 minutes (glucose, glucose+MLE, sucrose+MLE, and maltose+MLE) or 45 minutes (maltodextrin+MLE) before returning to preprandial levels at 120 minutes. At 30 minutes, the change in blood glucose level was lower for sucrose+MLE, maltose+MLE, and maltodextrin+MLE than for glucose or glucose+MLE (P < .05). GI was lowest for sucrose+MLE (43.22 ± 17.47) and maltose+MLE (49.23 ± 22.39), intermediate for maltodextrin+MLE (75.90 ± 26.01), and higher for glucose+MLE (91.88 ± 27.24). MLE reduced the GIs for maltose, sucrose, maltodextrin, and glucose by 53.11%, 33.51%, 31.00%, and 8.12%, respectively. MLE was well tolerated.

CONCLUSIONS

Coconsumption of MLE with sucrose, maltose, or maltodextrin can reduce the GI values of these carbohydrates.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Platform, no. ChiCTR-IPR-15006484. Registered on May 28, 2015.

Characterization of the PLP-dependent transaminase initiating azasugar biosynthesis

Biosynthesis of the azasugar 1-deoxynojirimycin (DNJ) critically involves a transamination in the first committed step. Here, we identify the azasugar biosynthetic cluster signature in Paenibacillus polymyxa SC2 (Ppo), homologous to that reported in Bacillus amyloliquefaciens FZB42 (Bam), and report the characterization of the aminotransferase GabT1 (named from Bam). GabT1 from Ppo exhibits a specific activity of 4.9 nmol/min/mg at 30°C (pH 7.5), a somewhat promiscuous amino donor selectivity, and curvilinear steady-state kinetics that do not reflect the predicted ping-pong behavior typical of aminotransferases. Analysis of the first half reaction with l-glutamate in the absence of the acceptor fructose 6-phosphate revealed that it was capable of catalyzing multiple turnovers of glutamate. Kinetic modeling of steady-state initial velocity data was consistent with a novel hybrid branching kinetic mechanism which included dissociation of PMP after the first half reaction to generate the apoenzyme which could bind PLP for another catalytic deamination event. Based on comparative sequence analyses, we identified an uncommon His-Val dyad in the PLP-binding pocket which we hypothesized was responsible for the unusual kinetics. Restoration of the conserved PLP-binding site motif via the mutant H119F restored classic ping-pong kinetic behavior.

Effect of different planting areas on the chemical compositions and hypoglycemic and antioxidant activities of mulberry leaf extracts in Southern China

Guangdong, Guangxi and Chongqing are emerging sericulture areas in China where the production of mulberry leaves is huge. In order to identity high quality mulberry leaves that are suitable for healthy products to expand planting, 24 samples from three regions (Guangdong, Guangxi, Chongqing) in the south of China were quantified for two alkaloids (1-deoxynojirimycin and fagomine) and five phenols (chlorogenic acid, rutin, isoquercitrin, etc.) using high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Additionally, the total phenolic and total flavonoid contents, antioxidant and glycosidase inhibitory activities (hypoglycemic activity) were tested using different assays (DPPH, ABTS, FRAP) to comprehensively evaluate the quality of the mulberry leaves. The contents of DNJ and fagomine ranged from 0.401±0.003 to 5.309±0.036 mg/g and from 0.279±0.031 to 2.300±0.060 mg/g, respectively. The main phenolic constituents were chlorogenic acid, rutin and isoquercitrin, with chlorogenic acid present in the highest concentrations, ranging from 3.104±0.191 to 10.050±0.143 mg/g. The antioxidant activity exhibited a tendency as follows: Guangxi > Guangdong > Chongqing, except for two samples from Chongqing, which showed the highest antioxidant activity. Based on our study, mulberry leaves from Guangdong and Guangxi could be future sources of natural hypoglycemic and antioxidant products.

Protein Tyrosine Phosphatase 1B Inhibition and Glucose Uptake Potentials of Mulberrofuran G, Albanol B, and Kuwanon G from Root Bark of Morus alba L. in Insulin-Resistant HepG2 Cells: An In Vitro and In Silico Study

Type II diabetes mellitus (T2DM) is the most common form of diabetes and has become a major health problem across the world. The root bark of Morus alba L. is widely used in Traditional Chinese Medicine for treatment and management of diabetes. The aim of the present study was to evaluate the enzyme inhibitory potentials of three principle components, mulberrofuran G (1), albanol B (2), and kuwanon G (3) in M. alba root bark against diabetes, establish their enzyme kinetics, carry out a molecular docking simulation, and demonstrate the glucose uptake activity in insulin-resistant HepG2 cells. Compounds 1–3 showed potent mixed-type enzyme inhibition against protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase. In particular, molecular docking simulations of 1–3 demonstrated negative binding energies in both enzymes. Moreover, 1–3 were non-toxic up to 5 µM concentration in HepG2 cells and enhanced glucose uptake significantly and decreased PTP1B expression in a dose-dependent manner in insulin-resistant HepG2 cells. Our overall results depict 1–3 from M. alba root bark as dual inhibitors of PTP1B and α-glucosidase enzymes, as well as insulin sensitizers. These active constituents in M. alba may potentially be utilized as an effective treatment for T2DM.

BmSUC1 is essential for glycometabolism modulation in the silkworm, Bombyx mori

Sucrose is the most commonly transported sugar in plants and is easily assimilated by insects to fulfill the requirement of physiological metabolism. BmSuc1 is a novel animal β-fructofuranosidase (β-FFase, EC 3.2.1.26)-encoding gene that was firstly cloned and identified in silkworm, Bombyx mori. BmSUC1 was presumed to play an important role in the silkworm-mulberry enzymatic adaptation system by effectively hydrolyzing sucrose absorbed from mulberry leaves. However, this has not been proved with direct evidence thus far. In this study, we investigated sucrose hydrolysis activity in the larval midgut of B. mori by inhibition tests and found that sucrase activity mainly stemmed from β-FFase, not α-glucosidase. Next, we performed shRNA-mediated transgenic RNAi to analyze the growth characteristics of silkworm larvae and variations in glycometabolism in vivo in transgenic silkworms. The results showed that in the RNAi-BmSuc1 transgenic line, larval development was delayed, and their body size was markedly reduced. Finally, the activity of several disaccharidases alone in the midgut and the sugar distribution, total sugar and glycogen in the midgut, hemolymph and fat body were then determined and compared. Our results demonstrated that silencing BmSuc1 significantly reduced glucose and apparently activated maltase and trehalase in the midgut. Together with a clear decrease in both glycogen and trehalose in the fat body, we conclude that BmSUC1 acts as an essential sucrase by directly modulating the degree of sucrose hydrolysis in the silkworm larval midgut, and insufficient sugar storage in the fat body may be responsible for larval malnutrition and abnormal petite phenotypes.

Role of Plant-Derived Flavonoids and Their Mechanism in Attenuation of Alzheimer's and Parkinson's Diseases: An Update of Recent Data

Neurodegeneration is a progressive loss of neuronal cells in certain regions of the brain. Most of the neurodegenerative disorders (NDDs) share the communal characteristic such as damage or reduction of various cell types typically including astrocytes and microglial activity. Several compounds are being trialed to treat NDDs but they possess solitary symptomatic advantages along with copious side effects. The finding of more enthralling and captivating compounds to suspend and standstill the pathology of NDDs will be considered as a hallmark of present times. Phytochemicals possess the potential to alternate the synthetic line of therapy against NDDs. The present review explores the potential efficacy of plant-derived flavonoids against most common NDDs including Alzheimer's disease (AD) and Parkinson's disease (PD). Flavonoids are biologically active phytochemicals which possess potential pharmacological effects, including antiviral, anti-allergic, antiplatelet, anti-inflammatory, anti-tumor, anti-apoptotic and anti-oxidant effects and are able to attenuate the pathology of various NDDs through down-regulating the nitric oxide (NO) production, by reducing the tumor necrosis factor-α (TNF-α), by reducing the excitotoxicity of superoxide as well as acting as tyrosine kinase (TK) and monoamine oxidase (MAO) inhibiting enzyme.

Proteomic-Based Approach to the Proteins Involved in 1-Deoxynojirimycin Accumulation in Silkworm Bombyx mori (Lepidoptera: Bombycidae)

1-Deoxynojirimycin (DNJ) is the most abundant poly-hydroxylated alkaloid in the latex of mulberry leaves and it protects mulberry from insect predation. However, silkworms can survive the poisoning effect of DNJ and accumulate DNJ by consumption of the mulberry leaves. In order to determine the molecular mechanism of DNJ accumulation in silkworm, comparative proteomic analysis was employed to evaluate protein expression in two groups of silkworm bodies (the third instar silkworm bodies had the maximum content of DNJ throughout life, and the newly hatched silkworm bodies had no DNJ). Our results indicated some differentially expressed proteins in the third instar silkworm involved in material metabolism, energy metabolism, oxidation-reduction, detoxification, immune, and transport regulation may correspond to the accumulation of DNJ. Furthermore, the expression levels of five selected differentially expressed protein-encoding genes namely heat shock cognate protein (Hsp 70), glutathione S-transferase sigma 1 (GST), serine protease precursor (Ser), hemolymph protein (30K), and thiol peroxiredoxin (TPx) were investigated by quantitative real-time PCR and the accumulation of DNJ was measured by HPLC. Correlation analysis showed that the expression levels of Hsp70 and Ser were negatively correlated to DNJ accumulation with weak correlation, while 30K, GST, and TPx genes had positive correlation with DNJ accumulation. The findings suggested that these three proteins were probably important in the physiological process of DNJ accumulation in silkworm.

Ethnopharmacological implications of quantitative and network analysis for traditional knowledge regarding the medicinal use of animals by indigenous people in Wolchulsan National Park, Korea

ETHNOPHARMACOLOGICAL RELEVANCE

The purpose of this study was to record, analyze, and identify ethnopharmacological implications for oral traditional knowledge regarding the medicinal use of animals by indigenous people living in Wolchulsan National Park, Korea.

MATERIALS AND METHODS

Data were collected through interviews, informal meetings, open and group discussions, and observations guided by semi-structured questionnaires. Data were analyzed via quantitative analysis of informant consensus factor and fidelity level, and network analysis, including centrality and clustering analysis.

RESULTS

A total of 46 families, 59 genera, and 60 species of animals, as well as 373 methods of usage, were recorded. Fish comprised 31.7% of the total animal species recorded, followed by mammals at 20.0%, arthropods at 18.3%, and mollusks at 11.7%. Of these animals, 48.0% were utilized as food and 46.1% for medicinal use. Quantitative analysis showed that the category with the highest degree of consensus from informants was veterinary ailments (informant consensus factor value, 0.96). This was followed by poisonings (0.93), pains (0.92), genitourinary system disorders (0.91), cuts and wounds (0.89), and other medical conditions. The lowest degree of consensus was for skin diseases and disorders (0.57). There were 8 species of animals with a fidelity level of 100%, after eliminating from the animals analyzed that were mentioned only once. Finally, using network analysis, Gallus gallus domesticus and Gloydius brevicaudus were defined as species with meaningful medicinal use, while lack of vigor and lung diseases were defined as significant ailments in the study area.

CONCLUSION

This study validates that local communities use animals not only for food but also for medicinal purposes as crucial therapeutic measures. Therefore, the conservation of fauna and preservation of traditional knowledge need to be seriously considered to maintain the health and well-being of the local communities. Network analysis clarified the series of ailments for which each animal species is preferentially used and helped confirm the order of priority when prescribing animal components for medicinal use. The traditional knowledge recorded in the present study will provide the basic data to develop new medicines for the bioindustry.

Role of ethanolic extract of Morus alba leaves on some biochemical and hematological alterations in irradiated male rats

PURPOSE

The present study aimed to evaluate the protective role of "Morus alba Linn (Family: Moraceae) commonly known as mulberry" leaves extract against hazardous effects of gamma rays in male rats.

MATERIALS AND METHODS

Thirty six male albino rats were divided into six groups (six rats/group); (1) control group received 1 ml distilled water, (2) low dose of extract (100 mg/kg) group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg body weight (b.wt.)) for 21 consecutive days, (3) high dose of extract (200 mg/kg) group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for the same period, (4) irradiated group rats were subjected to whole body gamma irradiation at a shot dose of 7 Gy, (5) low dose of extract + irradiated group treated daily with low oral dose of ethanolic extract of mulberry leaves (100 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy, (6) high dose of extract + irradiation group treated daily with high oral dose of ethanolic extract of mulberry leaves (200 mg/kg b.wt.) for 21 consecutive days then rats were exposed to gamma irradiation at a single dose of 7 Gy. Rats were sacrificed 1, 7, 15 days post gamma irradiation in all groups. Blood samples were taken at three intervals time in the six groups.

RESULTS

The results showed that whole body irradiation of rats induced significant decrease (p < 0.05) in red blood cells (RBCs), hemoglobin (Hb), hematocrit percentage (HCT%), platelet, white blood cells (WBCs), lymphocytes, neutrophils, serum glucose-6-phosphate dehydrogenase (G-6-PD) and insulin. The data also showed significant increase (p < 0.05) in serum total lipids, phospholipids, cholesterol, triglycerides, lactate dehydrogenase (LDH), creatine kinase (CK), and plasma glucose. Administration of mulberry leaves extract, either low or high concentrations to rats prior to irradiation caused significant improvement in the studied parameters.

CONCLUSIONS

Mulberry leaves extract prior to exposure to gamma irradiation has radio protector against hazardous effect of irradiation in male rats.

Seasonal variations of iminosugars in mulberry leaves detected by hydrophilic interaction chromatography coupled with tandem mass spectrometry

A rapid, sensitive, and validated method was developed for the simultaneous determination of four iminosugars, 1-deoxynojirimycin (DNJ), d-fagomine (FAG), 2-O-a-d-galactopyranosyl-DNJ (Gal-DNJ), and 4-O-β-d-glucopyranosyl-fagomine (Glu-FAG), in mulberry leaves. The method used hydrophilic interaction chromatography coupled with tandem mass spectrometry. Based on this method, the seasonal variations of iminosugars in the leaves of different mulberry species (Morus alba, Morus multicaulis Perr, Morus atropurpurea Roxb. and Morus wittiorum Hand-Mazz.) collected in Guangzhou, China, during 10 consecutive months in 2013 were investigated. The results indicated that the maximum content of DNJ in the leaves of all four species occurred in summer (June or July). The highest FAG level was found in spring (April or May). The highest levels of Gal-DNJ and Glu-FAG were recorded in autumn (September or October).

Distinguishing Six Edible Berries Based on Metabolic Pathway and Bioactivity Correlations by Non-targeted Metabolite Profiling

Berries have been used as valuable sources of polyphenols for human health; however, injudicious uses of berries are widespread without regard to the specific metabolite constituent of each berry. We classified 6 different edible berries (honeyberry, blueberry, mandarin melonberry, mulberry, chokeberry, and Korean black raspberry) based on their metabolite distributions in biosynthetic pathways by non-targeted metabolite profiling and bioactive correlation analysis. Principal component analysis revealed a distinct clustering pattern of metabolites for each berry. Metabolic pathway analysis revealed different biosynthetic routes of secondary metabolites in each berry. Mandarin melonberry contains a relatively higher proportion of genistein, genistein glycoside, and genistein-derived isoflavonoids and prenylflavonoids than the other berries. Various anthocyanin glycosides, synthesized from dihydroquercetin and cyanidin, were more abundant in chokeberry and honeyberry, whereas high levels of flavonoid-and anthocyanins-rutinoside forms were observed in Korean black raspberry. The levels of anthocyanins derived from dihydromyricetin were high in blueberry. The highest anti-oxidant activity was observed in chokeberry and Korean black raspberry, which is positively related to the proportional concentration of flavonoids, phenolics, and anthocyanins. The lowest sugar contents were observed in Korean black raspberry, highest acidity in honeyberry, and lowest acidity in mandarin melonberry, which were specific characteristics among the berries. Taken together, biosynthetic pathway and physicochemical characteristics analyses revealed that the different synthesized routes of flavonoids and anthocyanins and associated bio-activities may be distinct features in each berry and explain their phenotypic diversity at the molecular level.

Mulberry leaf alleviates streptozotocin-induced diabetic rats by attenuating NEFA signaling and modulating intestinal microflora

Improvement of hyperglycemia through dietotherapy/herbal remedy is an effective approach to treating diabetes. In this study, mulberry leaf, famous for silkworm’s special food and therapeutic value without any side effects, alleviated diabetes by attenuating NEFA signaling and modulating intestinal microflora. Mulberry leaf treatment significantly reduce fasting blood-glucose and HbA1c, ameliorate the blood lipid profile and improve insulin resistance in streptozotocin-induced diabetic rats. Mechanistically, we found that mulberry leaf inhibited NEFA signaling by reducing downstream signaling in the NEFA pathway, further verified by reduced PKC and improved cellular energy homeostasis based on restored expression of PGC-1α, AK2, OXPHOS and adiponectin. Mulberry leaf treatment also restored the phyla Bacteroidetes and Proteobacteria and class Clostridia, which were associated with insulin resistance and diabetes. Our findings reveal that mulberry leaf is an edible with therapeutic potential for diabetes and may provide a novel dietotherapy/herbal remedy to the treatment of diabetes.

Mulberry leaf extract decreases digestion and absorption of starch in healthy subjects-A randomized, placebo-controlled, crossover study

PURPOSE

Mulberry (Morus alba L.) leaf tea has recently received much attention as a dietary supplement due to the wide range of putative health benefits, such as antidiabetic effects. Nevertheless, data evaluating its influence on carbohydrate metabolism in humans are scarce. The present study aims to investigate the effect of mulberry leaf extract supplementation on starch digestion and absorption in humans.

MATERIALS AND METHODS

The study comprised of 25 healthy subjects, aged 19-27 years. In all subjects, a starch 13C breath test was performed twice in a crossover and single blind design. Subjects were initially randomized to ingest naturally 13C-abundant cornflakes (50g cornflakes+100ml low fat milk) either with the mulberry leaf extract (36mg of active component-1-deoxynojirimycin) or the placebo and each subject received the opposite preparation one week later.

RESULTS

The cumulative percentage dose recovery was lower for the mulberry leaf extract test than for the placebo test (median [quartile distribution]: 13.9% [9.9-17.4] vs. 17.2% [13.3-20.6]; p=0.015). A significant decrease was detectable from minute 120 after the ingestion.

CONCLUSIONS

A single dose of mulberry leaf extract taken with a test meal decreases starch digestion and absorption. These findings could possibly be translated into everyday practice for improvement of postprandial glycemic control.

1-Deoxynojirimycin: Sources, Extraction, Analysis and Biological Functions

1-Deoxynojirimycin (DNJ), a natural polyhydroxylated piperidine alkaloid, is attracting growing attention due to its important biological functions. This paper introduces the discovery and origins of DNJ, its extraction, purification, and physiological functions in the treatment of diabetes. The mechanisms of DNJ in the inhibition of fat accumulation and tumor cell metastasis are also discussed. In addition, the prospects and challenges of DNJ for practical production are proposed. This work aims to provide technical advice on obtaining DNJ and a fuller understanding of its biological activities.

Accumulation of Flavonoid Glycosides and UFGT Gene Expression in Mulberry Leaves (Morus alba L.) before and after Frost

In order to determine the molecular mechanism underlying the influence of frost on chemical changes in mulberry leaves, the UFGT activity, expression level, and accumulation of flavonoid glycosides in mulberry leaves (Morus alba L.) were studied. The expression of UFGT gene was investigated by quantitative real-time PCR (qRT-PCR) and the UFGT activity, accumulation of flavonoid glycosides was studied by high performance liquid chromatography. Then, the correlation between the expression level of UFGT, the UFGT activity, and the flavonoid glycosides accumulation with temperature was explored. The accumulation of isoquercitrin and astragalin is significantly positively correlated with UFGT gene expression and UFGT activity. On the contrary, the average temperature was significantly negatively correlated with the level of UFGT gene expression and UFGT activity. The results show that after frost, low temperature can induce the expression of UFGT gene in mulberry leaves, resulting in the accumulation of flavonoid glycosides.

Constituent analysis of the ethanol extracts of Chimonanthus nitens Oliv. leaves and their inhibitory effect on α-glucosidase activity

The ethanol extracts of Chimonanthus nitens Oliv. leaves were prepared sequentially by ethanol gradient elution and tested for their α-glucosidase inhibitory. The fraction of 50% ethanol eluate (EE) exhibited the notable inhibition with IC50 of 0.376mg/mL. Also, 50% EE was chemically characterized by liquid chromatography-mass spectrometry (LC-MS) analysis. Eight compounds including rutin (1), hyperin (2), isoquercitrin (3), luteoloside (4), astragalin (6), quercetin (13), naringenin (14), kaempferol (15) were identified by compared with standard substances as well as proper luteolin-5-O-glucoside (5), kaempferol-7-O-rhamnoside (9), 5,7,8-trihydroxy-2-methoxyl-flavone-7-O-glucoside (10), kaempferol-7-O-acetyl-galactoside (11). The experiments of ultra-filtration combined with liquid chromatography-mass spectrometry (UF-LC-MS) guided quercetin and kaempferol as the key factors for 50% EE showing highly inhibitory activity on α-glucosidase. Quercetin and kaempferol inhibited yeast α-glucosidase in a mixed-type manner with IC50 of 66.8 and 109μg/mL, respectively. These results would provide theoretical underpinning for the C. nitens Oliv. leaves ethanol extracts used as nutraceutical health supplement in the management of type 2 diabetes.

Comparison of Different Strains of Agrobacterium rhizogenes for Hairy Root Induction and Betulin and Betulinic Acid Production in Morus alba

Three Agrobacterium rhizogenes strains were tested for their ability to transform the plant Morus alba L. and to induce production of the secondary metabolites betulin and betulinic acid. All the tested strains of A. rhizogenes (R1601, LBA9402 and R1000) were able to induce hairy root formation in leaf tissue explants. Strain LBA9402 had the highest rate of infection (92.7% ± 8.8%), whereas strain R1601 had the lowest rate (87.4% ± 9.3%). The highest number of hairy roots per explant (5.6 ± 0.5) and the greatest root length (2.4 ± 0.2 mm) were obtained with strain LBA9402. We also evaluated dry weight (a measure of growth) and betulin and betulinic acid production in hairy roots and found that the highest growth (167.8 ± 14.5 mg/flask) occurred after infection with strain LBA9402. Furthermore the highest production of betulin (5.4 ± 0.4 mg/g dry weight) and betulinic acid (2.3 ± 0.2 mg/g dry weight) was noted using strain LBA9402. Among three elicitors, yeast extract showed the highest induction of betulin production (8.7 ± 0.4 mg/g) and silver nitrate induced the highest yield of betulinic acid (4.1 ± 0.2 mg/g). Our study showed that A. rhizogenes strain LBA9402 was the most effective of the three tested strains for production of transformed root cultures and betulin and betulinic acid.