Extraction and identification of three major aldose reductase inhibitors from Artemisia montana

1,5-Dicaffeoylquinic acid from Pseudognaphalium affine ameliorates dry eye disease via suppression of inflammation and protection of the ocular surface

PURPOSE

Pseudognaphalium affine (P. affine), a medicinal plant, has long been used to treat various diseases due to its astringent and vulnerary effects. These therapeutic benefits are largely attributed to high contents of phytochemicals, such as flavonoids and polyphenols, that have anti-inflammatory and tissue-protective activities. Herein, we investigated the potential of dicaffeoylquinic acids (diCQAs), polyphenols from P. affine, as a novel treatment for dry eye disease (DED).

METHODS

We isolated 1,5-, 3,4-, 3,5- and 4,5-diCQAs from the P. affine methanol extract, and tested the effects of diCQA isomers in cultures of human corneal epithelial cells (CECs) under desiccating hyperosmolar stress and in two mouse models for DED: desiccating environmental stress-induced DED and the NOD.B10-H2b mouse model of ocular Sjögren's syndrome.

RESULTS

Initial screening showed that, among the diCQAs, 1,5-diCQA significantly inhibited apoptosis and enhanced viability in cultures of CECs under hyperosmolar stress. Moreover, 1,5-diCQA protected CECs by promoting proliferation and downregulating inflammatory activation. Subsequent studies with two mouse models of DED revealed that topical 1,5-diCQA administration dose-dependently decreased corneal epithelial defects and increased tear production while repressing inflammatory cytokines and T cell infiltration on the ocular surface and in the lacrimal gland. 1,5-diCQA was more effective in alleviating DED, as compared with two commercially-available dry eye treatments, 0.05% cyclosporine and 0.1% sodium hyaluronate eye drops.

CONCLUSIONS

Together, our results demonstrate that 1,5-diCQA isolated from P. affine ameliorates DED through protection of corneal epithelial cells and suppression of inflammation, thus suggesting a novel DED therapeutic strategy based on natural compounds.

Umbelliferon: a review of its pharmacology, toxicity and pharmacokinetics

Coumarin, a plant secondary metabolite, has various pharmacological activities, including antioxidant stress and anti-inflammatory effects. Umbelliferone, a common coumarin compound found in almost all higher plants, has been extensively studied for its pharmacological effects in different disease models and doses with complex action mechanisms. This review aims to summarize these studies and provide useful information to relevant scholars. The pharmacological studies demonstrate that umbelliferone has diverse effects such as anti-diabetes, anti-cancer, anti-infection, anti-rheumatoid arthritis, neuroprotection, and improvement of liver, kidney, and myocardial tissue damage. The action mechanisms of umbelliferone include inhibition of oxidative stress, inflammation, and apoptosis, improvement of insulin resistance, myocardial hypertrophy, and tissue fibrosis, in addition to regulation of blood glucose and lipid metabolism. Among the action mechanisms, the inhibition of oxidative stress and inflammation is the most critical. In short, these pharmacological studies disclose that umbelliferone is expected to treat many diseases, and more research should be conducted.

Unearthing of the Antidiabetic Potential of Aqueous Extract of Solanum betaceum Cav. Leaves

Solanum betaceum Cav., commonly known as tamarillo or Brazilian tomato, belongs to the Solanaceae family. Its fruit is used in traditional medicine and food crops due to its health benefits. Despite the numerous studies involving the fruit, there is no scientific knowledge about the tamarillo tree leaves. In this work, the phenolic profile of aqueous extract obtained from S. betaceum leaves was unveiled for the first time. Five hydroxycinnamic phenolic acids were identified and quantified, including 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, chlorogenic acid, caffeic acid and rosmarinic acid. While the extract displayed no effect on α-amylase, the extract inhibited the activity of α-glucosidase (IC₅₀ = 1617 mg/mL), and it was particularly effective for human aldose reductase (IC₅₀ = 0.236 mg/mL): a key enzyme in glucose metabolism. Moreover, the extract exhibited interesting antioxidant properties, such as a potent capacity to intercept the in vitro-generated reactive species O₂^•- (IC₅₀ = 0.119 mg/mL) and ^•NO (IC₅₀ = 0.299 mg/mL), as well as to inhibit the first stages of lipid peroxidation (IC₅₀ = 0.080 mg/mL). This study highlights the biological potential of S. betaceum leaves. The scarcity of research on this natural resource underscores the need for additional studies in order to fully explore its antidiabetic properties and to promote the value of a species currently at risk of extinction.

Fishing the Targets of Bioactive Compounds from Psidium guajava L. Leaves in the Context of Diabetes

Psidium guajava L. (guava) leaves have demonstrated their in vitro and in vivo effect against diabetes mellitus (DM). However, there is a lack of literature concerning the effect of the individual phenolic compounds present in the leaves in DM disease. The aim of the present work was to identify the individual compounds in Spanish guava leaves and their potential contribution to the observed anti-diabetic effect. Seventy-three phenolic compounds were identified from an 80% ethanol extract of guava leaves by high performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry. The potential anti-diabetic activity of each compound was evaluated with the DIA-DB web server that uses a docking and molecular shape similarity approach. The DIA-DB web server revealed that aldose reductase was the target protein with heterogeneous affinity for compounds naringenin, avicularin, guaijaverin, quercetin, ellagic acid, morin, catechin and guavinoside C. Naringenin exhibited the highest number of interactions with target proteins dipeptidyl peptidase-4, hydroxysteroid 11-beta dehydrogenase 1, aldose reductase and peroxisome proliferator-activated receptor. Compounds catechin, quercetin and naringenin displayed similarities with the known antidiabetic drug tolrestat. In conclusion, the computational workflow showed that guava leaves contain several compounds acting in the DM mechanism by interacting with specific DM protein targets.

Ursonic acid from Artemisia montana exerts anti-diabetic effects through anti-glycating properties, and by inhibiting PTP1B and activating the PI3K/Akt signaling pathway in insulin-resistant C2C12 cells

Artemisia is one of the largest genera in the plant family Asteraceae and has long been used in traditional medicine for its antitussive, analgesic, antihypertensive, antitoxic, antiviral, antimalarial, and anti-inflammatory properties. However, the anti-diabetic activity of Artemisia montana has not been broadly studied. The goal of this study was to determine whether extracts of the aerial parts of A. montana and its main constituents inhibit protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase activities. We isolated nine compounds from A. montana including ursonic acid (UNA) and ursolic acid (ULA), which significantly inhibited PTP1B with IC₅₀ values of 11.68 and 8.73 μM, respectively. In addition, UNA showed potent inhibitory activity against α-glucosidase (IC₅₀ = 61.85 μM). Kinetic analysis of PTP1B and α-glucosidase inhibition revealed that UNA was a non-competitive inhibitor of both enzymes. Docking simulations of UNA demonstrated negative binding energies and close proximity to residues in the binding pockets of PTP1B and α-glucosidase. Molecular docking simulations between UNA and human serum albumin (HSA) revealed that UNA binds tightly to all three domains of HSA. Furthermore, UNA significantly inhibited fluorescent AGE formation (IC₅₀ = 4.16 μM) in a glucose-fructose-induced HSA glycation model over the course of four weeks. Additionally, we investigated the molecular mechanisms underlying the anti-diabetic effects of UNA in insulin-resistant C2C12 skeletal muscle cells and discovered that UNA significantly increased glucose uptake and decreased PTP1B expression. Further, UNA increased GLUT-4 expression level by activating the IRS-1/PI3K/Akt/GSK-3 signaling pathway. These findings clearly demonstrate that UNA from A. montana shows great potential for treatment of diabetes and its complications.

Screening inhibitory effects of selected flavonoids on human recombinant aldose reductase enzyme: in vitro and in silico study

Aldose reductase (AR) is the first enzyme of the polyol pathway that has physiological importance under hyperglycaemic conditions. The article has been focussed on AR enzyme inhibition by selected compounds. For this purpose, the in vitro inhibitory effects of various compounds on commercially available recombinant human AR (rAR) enzyme activity were investigated. The IC₅₀ values of compounds on rAR inhibition effect were found for 6-hydroxy flavone, syringic acid, diosmetin, 6-fluoroflavone, 7-hydroxy-4'-nitroisoflavone, myricetin as 2.05, 2.97, 15.75, 16.1, 49.5, and 63 µM, respectively. 6-Hydroxy flavone and syringic acid competitively inhibited rAR with respect to the NADPH with K_i values 0.509 ± 0.036 and 0.842 ± 0.012 µM. In addition, docking studies were performed to evaluate the potential enzyme binding positions of the compounds. Our in vitro and in silico results indicated that the 6-hydroxy flavone may be a good lead compound in the development of AR inhibitors to prevent diabetic complications.

Biological effects of bis-hydrazone compounds bearing isovanillin moiety on the aldose reductase

Aldose reductase (ALR2), one of the metabolically important enzymes, catalyzes the formation of sorbitol from glucose in the polyol pathway. ALR2 inhibition is required to prevent diabetic complications. In the present study, the novel bis-hydrazone compounds bearing isovanillin moiety (GY1-12) were synthesized, and various chromatographic methods were applied to purify the ALR2 enzyme. Afterward, the inhibitory effect of the synthesized compounds on the ALR2 was screened in vitro. All the novel bis-hydrazones demonstrated activity in nanomolar levels as AR inhibitors with IC₅₀ and K_I values in the range of 12.55-35.04 nM, and 13.38-88.21 nM, respectively. Compounds GY-11, GY-7, and GY-5 against ALR2 were identified as the highly potent inhibitors, respectively, and were superior to the standard drug, epalrestat. Moreover, a comprehensive ligand-receptor interactions prediction was performed using ADME-Tox, Glide XP, and MM-GBSA modules of Schrödinger Small-Molecule Drug Discovery Suite to elucidate the novel bis-hydrazone derivatives, potential binding modes versus the ALR2. As a result, these compounds with ALR2 inhibitory effects may be potential alternative agents that can be used to treat or prevent diabetic complications.

Natural Compounds as Source of Aldose Reductase (AR) Inhibitors for the Treatment of Diabetic Complications: A Mini Review

BACKGROUND

Aldol reductase (AR) is the polyol pathway's main enzyme that portrays a crucial part in developing 'complications of diabetes' involving cataract, retinopathy, nephropathy, and neuropathy. These diabetic abnormalities are triggered tremendously via aggregation of sorbitol formation (catalyzed by AR) in the polyol pathway. Consequently, it represents an admirable therapeutic target and vast research was done for the discovery of novel molecules as potential AR inhibitors for diabetic complications.

OBJECTIVE

This review article has been planned to discuss an outline of diabetic complications, AR and its role in diabetic complications, natural compounds reported as AR inhibitors, and benefits of natural/plant derived AR inhibitors for the management of diabetic abnormalities.

RESULTS

The goal of AR inhibition remedy is to stabilize the increased flux of blood glucose and sorbitol via the 'polyol pathway' in the affected tissues. A variety of synthetic inhibitors of AR have been established such as tolrestat and sorbinil, but both of these face limitations including low permeability and health problems. Pharmaceutical industries and other scientists were also undertaking work to develop newer, active, and 'safe' AR inhibitors from natural sources. Therefore, several naturally found molecules were documented to possess a potent inhibitory action on AR activity.

CONCLUSION

Natural inhibitors of AR appeared as harmless pharmacological agents for controlling diabetic complications. The detailed literature throughout this article shows the significance of herbal extracts and phytochemicals as prospective useful AR inhibitors in treating diabetic complications.

Chemical constituent with cytotoxicity from Sterculia diversifolia

One new coumarin (stercularin), along with eleven known compounds, was isolated for the first time from ethyl acetate fraction of Sterculia diversifolia. The structures of isolated compounds were characterized by spectroscopic techniques such as EIMS, ¹H-NMR and ¹³C-NMR. Compound 1 showed significant cytotoxicity by brine shrimp lethality assay (LD₅₀: 8.00 μg/ml) and PC-3 cell lines protocol (IC₅₀: 3.92 ± 0.20 μg/ml), respectively.

Phenolics Profiling of Carpobrotus edulis (L.) N.E.Br. and Insights into Molecular Dynamics of Their Significance in Type 2 Diabetes Therapy and Its Retinopathy Complication

Adverse effects associated with synthetic drugs in diabetes therapy has prompted the search for novel natural lead compounds with little or no side effects. Effects of phenolic compounds from Carpobrotus edulis on carbohydrate-metabolizing enzymes through in vitro and in silico methods were assessed. Based on the half-maximal inhibitory concentrations (IC₅₀), the phenolic extract of the plant had significant (p < 0.05) in vitro inhibitory effect on the specific activity of alpha-amylase (0.51 mg/mL), alpha-glucosidase (0.062 mg/mL) and aldose reductase (0.75 mg/mL), compared with the reference standards (0.55, 0.72 and 7.05 mg/mL, respectively). Molecular interactions established between the 11 phenolic compounds identifiable from the HPLC chromatogram of the extract and active site residues of the enzymes revealed higher binding affinity and more structural compactness with procyanidin (−69.834 ± 6.574 kcal/mol) and 1,3-dicaffeoxyl quinic acid (−42.630 ± 4.076 kcal/mol) as potential inhibitors of alpha-amylase and alpha-glucosidase, respectively, while isorhamnetin-3-O-rutinoside (−45.398 ± 4.568 kcal/mol) and luteolin-7-O-beta-d-glucoside (−45.102 ± 4.024 kcal/mol) for aldose reductase relative to respective reference standards. Put together, the findings are suggestive of the compounds as potential constituents of C. edulis phenolic extract responsible for the significant hypoglycemic effect in vitro; hence, they could be exploited in the development of novel therapeutic agents for type-2 diabetes and its retinopathy complication.

Macroporous resin-assisted enrichment, characterizations, antioxidant and anticandidal potential of phytochemicals from Trachyspermum ammi

Extract of de-oiled seeds of Trachyspermum ammi was purified using macroporous resins and the performance of three resins were evaluated to enrich major phytochemical component. A HPLC method has been developed to separate major phytochemical constituents in the crude (CTAE) and partially purified extracts (PTAE). Macroporous resin assisted enrichment and purification suggested XAD-16 as the most efficient (yield 29.8%) followed by XAD-7HP and Diaion HP-20. Concentrated PTAE was subjected to multiple preparative-TLC to afford three compounds, namely, rosmarinic acid-3-O-glucopyranoside (TA-1), kaempferol-(coumaroyl-glucosyl)-rhamnoside (TA-2) and quercetin-3-O-galactoside (TA-3). The structure of these compounds was elucidated from their corresponding spectroscopic characterizations in FT-IR, HR-MS, and partially by ¹ H NMR. Total phenolic and flavonoid contents of the extracts were determined. Antioxidant activity by DPPH and ABTS radical scavenging, CUPRAC assays indicated the highest antioxidant potential of CTAE. Among the compounds, TA-1 exhibited the highest scavenging activity in ABTS (IC₅₀ 33.41 µg/ml) and DPPH (IC₅₀ 69.23 µg/ml), however, relatively lower than CTAE. In vitro anti-candidal activity against virulent strains of Candida spp. revealed C. albicans 4718 as the most susceptible (23.9 µg/ml) to PTAE. PRACTICAL APPLICATIONS: Seeds of Trachyspermum ammi has been extensively investigated for volatile aromatic components of the essential oil. However, the de-oiled seeds have rarely been exploited for potential bioactive phenolics. The present investigation envisaged possible utilization of the de-oiled Trachyspermum seeds for its phenolic constituents, which could be used as natural antioxidant with additional benefits of anticandidal properties. Indeed, macroporous resin assisted enrichment and purification of extracts of T. ammi seeds generate valuable reference compounds, rosmarinic acid-3-O-glucopyranoside, kaempferol-(coumaroyl glucosyl)-rhamnoside, and quercetin-3-O-galactoside.

Natural Aldose Reductase Inhibitor: A Potential Therapeutic Agent for Non-alcoholic Fatty Liver Disease

Aldose reductase (AR) has been reported to be involved in the development of nonalcoholic fatty liver disease (NAFLD). Hepatic AR is induced under hyperglycemia condition and converts excess glucose to lipogenic fructose, which contributes in part to the accumulation of fat in the liver cells of diabetes rodents. In addition, the hyperglycemia-induced AR or nutrition-induced AR causes suppression of the transcriptional activity of peroxisome proliferator-activated receptor (PPAR) α and reduced lipolysis in the liver, which also contribute to the development of NAFLD. Moreover, AR induction in non-alcoholic steatohepatitis (NASH) may aggravate oxidative stress and the expression of inflammatory cytokines in the liver. Here, we summarize the knowledge on AR inhibitors of plant origin and review the effect of some plant-derived AR inhibitors on NAFLD/NASH in rodents. Natural AR inhibitors may improve NAFLD at least in part through attenuating oxidative stress and inflammatory cytokine expression. Some of the natural AR inhibitors have been reported to attenuate hepatic steatosis through the regulation of PPARα-mediated fatty acid oxidation. In this review, we propose that the natural AR inhibitors are potential therapeutic agents for NAFLD.

Valorisation of kitul, an overlooked food plant: Phenolic profiling of fruits and inflorescences and assessment of their effects on diabetes-related targets

Caryota urens L. has long been valued as a traditional food, the edible fruits being eaten raw and the inflorescences commonly used on sweet sap and flour production. In the current work, the phenolic profile of methanol extracts obtained from the inflorescences and fruits was unveiled for the first time, nine caffeic acid derivatives being identified and quantified. Since kitul products have been reported for their antidiabetic properties, extracts radical scavenging activity and α-amylase, α-glucosidase and aldose reductase inhibitory activity were assessed. The inflorescences' extract was particularly active against yeast α-glucosidase (IC₅₀ = 1.53 μg/mL), acting through a non-competitive inhibitory mechanism. This activity was also observed in enzyme-enriched homogenates obtained from human Caco-2 cells (IC₅₀ = 64.75 µg/mL). Additionally, the extract obtained from the inflorescences showed no cytotoxicity on HepG2, AGS and Caco-2 cell lines. Our data suggest that C. urens inflorescences can support the development of new functional foods with α-glucosidase inhibitory activity.

Pharmacophore based virtual screening, molecular docking, molecular dynamics and MM-GBSA approach for identification of prospective SARS-CoV-2 inhibitor from natural product databases

COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily appeared in Wuhan, China, in December 2019. At present, no proper therapy and vaccinations are available for the disease, and it is increasing day by day with a high mortality rate. Pharmacophore based virtual screening of the selected natural product databases followed by Glide molecular docking and dynamics studies against SARS-CoV-2 main protease was investigated to identify potential ligands that may act as inhibitors. The molecules SN00293542 and SN00382835 revealed the highest docking score of −14.57 and −12.42 kcal/mol, respectively, when compared with the co-crystal ligands of PDB-6Y2F (O6K) and 6W63 (X77) of the SARS-CoV-2 M^pro. To further validate the interactions of top scored molecules SN00293542 and SN00382835, molecular dynamics study of 100 ns was carried out. This indicated that the protein-ligand complex was stable throughout the simulation period, and minimal backbone fluctuations have ensued in the system. Post-MM-GBSA analysis of molecular dynamics data showed free binding energy-71.7004 +/− 7.98, −56.81+/− 7.54 kcal/mol, respectively. The computational study identified several ligands that may act as potential inhibitors of SARS-CoV-2 M^pro. The top-ranked molecules SN00293542, and SN00382835 occupied the active site of the target, the main protease like that of the co-crystal ligand. These molecules may emerge as a promising ligands against SARS-CoV-2 and thus needs further detailed investigations.

Communicated by Ramaswamy H. Sarma

Esculetin and idebenone ameliorate galactose-induced cataract in a rat model

Cataract is the principal cause of blindness. The enzyme, aldose reductase (AR) is a key player in polyol pathway. Buildup of polyols and oxidative stress are the main causes of cataractogenesis. This study investigated the cytoprotective properties of esculetin and idebenone in galactose-induced cataract. Rats were partitioned into four groups each of ten rats. Control group was fed with normal diet; group 2 rats were fed with galactose diet (50%); groups 3, 4 rats were fed with galactose diet concurrently with either esculetin (50 mg/kg BW) or idebenone (100 mg/kg BW), for 20 days. The study revealed that esculetin and idebenone significantly reduced the elevated levels of Bax/Bcl-2 ratio, malondialdehyde, and DNA fragmentation and increased total antioxidant capacity level in lenses compared to the cataract-induced group. Only esculetin decreased AR, galactitol, and advanced glycated end products levels in lenses. Histopathological examinations supported the biochemical findings. Esculetin and idebenone may have chemopreventive effects for sugar cataract. PRACTICAL APPLICATIONS: Cataract is an age-related disease that might cause blindness in older adult people. Presently, no absolute pharmacological treatment is accessible for cataract. The use of natural products or their derivatives attract particular attention in modern medicines as they are believed to be safer with few or no side effects. Esculetin is a polyphenolic compound found in many medicinal plants. Idebenone is a synthetic analogue of coenzyme Q10. The current study is an approach to explore the anticataract effects of esculetin and idebenone in galactose-induced cataract in rats. Our study proved that both agents have anticataractogenic potentials due to their antioxidant and antiapoptotic properties.

Flower Infusions FromCornus masandCornus kousaInhibit Aldose Reductase Enzyme, Without Any Effects on Lipotoxicity

Aldose reductase inhibitors are considered to be potential therapeutic agents for chronic diabetic complications. Diabetes mellitus can be accompanied by elevated blood levels of free fatty acids, which can cause lipotoxicity. Herbal extracts and their constituents are promising agents which have the potential for alleviating these complications. Our study was focused on the influence on these effects by flower infusions from Cornus mas L. and Cornus kousa F.Buerger ex Hance. Initially, phenolic compounds were quantified in the dried flowers. Next, we studied the ability of flower infusions from both plants to inhibit aldose reductase in vitro, the protective role in the cell model of lipotoxicity, and the cytotoxic action on fibroblast cell line NIH-3T3 by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide assay. Both species are rich in phenolics; C. kousa flowers contain slightly higher amounts of phenolic acids (20.8%) and flavonoids (56.1%) than C. mas (20.2%) and (47.4%), respectively. Both extracts showed effective inhibition, expressed as half-maximal inhibitory concentration (IC50) (the concentration of inhibitor required to exhibit 50% inhibition of the enzyme reaction), of aldose reductase in non-toxic low concentrations (IC50= 3.06 μg/mL for C. mas and IC50= 2.49 μg/mL for C. kousa, respectively). In contrast, these concentrations of both extracts had almost no effects in the lipotoxicity cell model. To our knowledge, this study is the first report on C. mas and C. kousa flowers’ aldose reductase inhibitory activity and influence upon lipotoxicity.

The Protective Effects of Cryptochlorogenic Acid on β-Cells Function in Diabetes in vivo and vitro via Inhibition of Ferroptosis

PURPOSE

Mulberry leaf extract has exerted better antidiabetic activities, while the effects of major active components in mulberry leaf extract are still unclear. Cryptochlorogenic acid (CCA) as the major active component in mulberry leaf extracts was investigated herein.

MATERIALS AND METHODS

Rats were treated with 50mg/kg streptozotocin for the establishment of diabetic model in vivo, and cells were treated with 33.3 mM glucose for the establishment of cell model in vitro. HE staining assay was performed for observation of pancreatic pathology and aldehyde fuchsin staining assay for examining islet cell numbers. The iron content was detected via Perls staining assay with iron assay kit (ab83366). The malondialdehyde (MDA), glutathione (GSH) and oxidized glutathione (GSSG) were detected by corresponding kits. Real-time quantitative polymerase chain reaction (RT-qPCR) was performed for assessment of gene level and Western blot for measurement of protein expression level. The cell survival was detected via CCK-8 assay.

RESULTS

The blood glucose level, iron content, accumulation of lipid peroxides and islet injury in diabetic model were all improved by CCA via a concentration-dependent manner. CCA functions via inhibition of ferroptosis by activation of cystine/glutamate transporter system (XC^-)/glutathione peroxidase 4(GPX4)/Nrf2 and inhibition of nuclear receptor coactivator 4 (NCOA4) in diabetes.

CONCLUSION

CCA exerted excellent antidiabetic effects via inhibition of ferroptosis, so it may be a promising agent for diabetes therapy, providing a new avenue for diabetes treatment.

Antidiabetic properties of dietary phenolic compounds: Inhibition effects on α-amylase, aldose reductase, and α-glycosidase

Aldose reductase (AR), α-amylase, and α-glycosidase are vital enzymes to prevent diabetic complications. Here, AR was purified from sheep kidney using elementary methods with 111.11-purification fold and with 0.85% purification yield. The interactions between some phenolic compounds and the AR, α-glycosidase, and α-amylase enzyme were determined. It was found that phenolic compounds exhibit potential inhibitor properties for these enzymes. For α-amylase, studied phenolic compounds showed IC₅₀ values in the range of 601.56-2,067.78 nM. For α-glycosidase, K_i values were found in the range of 169.25 ± 27.22-572.88 ± 106.76 nM. For AR, K_i values in the range of 8.48 ± 0.56-43.26 ± 7.63 µM. However, genistein showed the best inhibition effect toward AR and α-glycosidase, but delphinidin chloride exhibited the best inhibition effect against α-amylase enzyme. We determined that all compounds showed noncompetitive inhibition effect against AR and α-glycosidase. Also, studied phenolic compounds may be useful in the prevention or treatment of diabetic complications.

Aldose Reductase, Protein Glycation Inhibitory and Antioxidant of Peruvian Medicinal Plants: the Case of Tanacetum parthenium L. and Its Constituents

Diabetes complications, including peripheral neuropathy, cataracts, impaired wound healing, vascular damage, arterial wall stiffening and retinopathy diseases, are among the most predominant health problems facing the world's population today. The 22 Peruvian plant extracts were screened for their potential inhibitory activity against rat lens aldose reductase (RLAR) and DPPH radical scavenging. Among them, we have found that Tanacetum parthenium L. (TP) has the RLAR, AGEs and DPPH radical scavenging activities. We used for screening of active components in TP against RLAR and DPPH for the first time by ultrafiltration (UF) and DPPH. Compounds in TP were isolated by Sephadex column chromatography and their structures were established by MS and NMR spectroscopic analyses. Among the isolated compounds, ferulic acid, apigenin, luteolin-7-O-glucoside, luteolin, chrysosplenol, and kaempferol showed potent inhibition with IC50 values of 1.11-3.20 and 6.44-16.23 μM for RLAR and DPPH radical scavenging. Furthermore, these compounds suppressed sorbitol accumulation in rat lenses and ferulic acid, luteolin-7-O-glucoside, and luteolin have AGEs inhibitory activities with IC50 values of 3.43-6.73 μM. In summary, our study provides interesting plants for further study with respect to the treatment and prevention of diabetic complication of Peruvian plant and can provide the scientific base of the traditional uses.

Cataract Preventive Role of Isolated Phytoconstituents: Findings from a Decade of Research

Cataract is an eye disease with clouding of the eye lens leading to disrupted vision, which often develops slowly and causes blurriness of the eyesight. Although the restoration of the vision in people with cataract is conducted through surgery, the costs and risks remain an issue. Botanical drugs have been evaluated for their potential efficacies in reducing cataract formation decades ago and major active phytoconstituents were isolated from the plant extracts. The aim of this review is to find effective phytoconstituents in cataract treatments in vitro, ex vivo, and in vivo. A literature search was synthesized from the databases of Pubmed, Science Direct, Google Scholar, Web of Science, and Scopus using different combinations of keywords. Selection of all manuscripts were based on inclusion and exclusion criteria together with analysis of publication year, plant species, isolated phytoconstituents, and evaluated cataract activities. Scientists have focused their attention not only for anti-cataract activity in vitro, but also in ex vivo and in vivo from the review of active phytoconstituents in medicinal plants. In our present review, we identified 58 active phytoconstituents with strong anti-cataract effects at in vitro and ex vivo with lack of in vivo studies. Considering the benefits of anti-cataract activities require critical evaluation, more in vivo and clinical trials need to be conducted to increase our understanding on the possible mechanisms of action and the therapeutic effects.

Bioactive Phenolics of the Genus Artemisia (Asteraceae): HPLC-DAD-ESI-TQ-MS/MS Profile of the Siberian Species and Their Inhibitory Potential Against α-Amylase and α-Glucosidase

Artemisia genus of Asteraceae family is a source of medicinal plants known worldwide and used as ethnopharmacological remedies for the treatment of diabetes in Northern Asia (Siberia). The aim of this study was to determine the phenolic profile of 12 Siberian Artemisia species (A. anethifolia, A. commutata, A. desertorum, A. integrifolia, A. latifolia, A. leucophylla, A. macrocephala, A. messerschmidtiana, A. palustris, A. sericea, A. tanacetifolia, A. umbrosa) and to test the efficacy of plant extracts and pure compounds for antidiabetic potential. Finally, by HPLC-DAD-ESI-TQ-MS/MS technique, 112 individual phenolic compounds were detected in Artemisia extracts in a wide range of concentrations. Some species accumulated rare plant phenolics, such as coumarin-hemiterpene ethers (lacarol derivatives) from A. latifolia and A. tanacetifolia; melilotoside from A. tanacetifolia; dihydrochalcones (davidigenin analogs) from A. palustris; chrysoeriol glucosides from A. anethifolia, A. sericea, and A. umbrosa; eriodictyol glycosides from A. messerschmidtiana; and some uncommon flavones and flavonols. The predominant phenolic group from Artemisia species herb was caffeoylquinic acid (CQAs), and in all species, the major CQAs were 5-O-CQA (20.28-127.99 μg/g) and 3,5-di-O-CQA (7.35-243.61 μg/g). In a series of in vitro bioassays, all studied Artemisia extracts showed inhibitory activity against principal enzymes of carbohydrate metabolism, such as α-amylase (IC₅₀ = 150.24-384.14 μg/mL) and α-glucosidase (IC₅₀ = 214.42-754.12 μg/mL). Although many phenolic compounds can be inhibitors, experimental evidence suggests that the CQAs were key to the biological response of Artemisia extracts. Mono-, di- and tri-substituted CQAs were assayed and showed inhibition of α-amylase and α-glucosidase, with IC₅₀ values of 40.57-172.47 μM and 61.08-1240.35 μM, respectively, and they were more effective than acarbose, a well-known enzyme inhibitor. The results obtained in this study reveal that Siberian Artemisia species and CQAs possess a pronounced inhibitory activity against α-amylase and α-glucosidase and could become a complement to synthetic antidiabetic drugs for controlling blood glucose level.

Evaluation of Aldose Reductase, Protein Glycation, and Antioxidant Inhibitory Activities of Bioactive Flavonoids in Matricaria recutita L. and Their Structure-Activity Relationship

The inhibitory activities of Matricaria recutita L. 70% methanol extract were evaluated by isolating and testing 10 of its compounds on rat lens aldose reductase (RLAR), advanced glycation end products (AGEs), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. Among these compounds, apigenin-7-O-β-D-glucoside, luteolin-7-O-β-D-glucoside, apigenin-7-O-β-D-glucuronide, luteolin-7-O-β-D-glucuronide, 3,5-O-di-caffeoylquinic acid, apigenin, and luteolin showed potent inhibition, and their IC₅₀ values in RLAR were 4.25, 1.12, 1.16, 0.85, 0.72, 1.72, and 1.42 μM, respectively. Furthermore, these compounds suppressed sorbitol accumulation in rat lens under high-glucose conditions, demonstrating their potential to prevent sorbitol accumulation ex vivo. Notably, luteolin-7-O-β-D-glucuronide and luteolin showed antioxidative as well as AGE-inhibitory activities (IC₅₀ values of these compounds in AGEs were 3.39 and 6.01 μM). These results suggest that the M. recutita extract and its constituents may be promising agents for use in the prevention or treatment of diabetic complications.

Inhibition behaviours of some phenolic acids on rat kidney aldose reductase enzyme: an in vitro study

Aldose reductase (AR) inhibitors have vital importance in the treatment and prevention of diabetic complications. In this study, rat kidney AR was purified 19.34-fold with a yield of 3.49% and a specific activity of 0.88 U/mg using DE-52 Cellulose anion exchange chromatography, gel filtration chromatography and 2'5' ADP Sepharose-4B affinity chromatography, respectively. After purification, the in vitro inhibition effects of some phenolic acids (tannic acid, chlorogenic acid, sinapic acid, protocatechuic acid, 4-hydroxybenzoic acid, p-coumaric acid, ferulic acid, vanillic acid, syringic acid, α-resorcylic acid, 3-hydroxybenzoic acid and gallic acid) were investigated on purified enzyme. We determined IC50, Ki values and inhibition types of these phenolic acids. As a result, tannic and chlorogenic acid had a strong inhibition effect. On the other hand, gallic acid had a weak inhibition effect. In this study, all phenolic acids except for chlorogenic acid and p-coumaric acid showed non-competitive inhibition effects on rat kidney AR.

Anti-hypoglycemic and hepatocyte-protective effects of hyperoside from Zanthoxylum bungeanum leaves in mice with high-carbohydrate/high-fat diet and alloxan-induced diabetes

The development of diabetes mellitus (DM) is accompanied by hyperglycemia-induced oxidative stress. Hyperoside is a major bioactive component in Zanthoxylum bungeanum leaves (HZL) and is a natural antioxidant. However, the effects of HZL on DM and its mechanisms of action remain undefined. The present study evaluated the anti-hypoglycemic and hepatocyte-protective effects of HZL in mice with diabetes induced by a high-carbohydrate/high-fat diet (HFD) and alloxan. We also aimed to eludicate the underlying mechanisms. Our resutls demonstrated that the administration of HZL significantly reduced body weight gain, serum glucose levels and insulin levels in diabetic mice compared with the vehicle-treated mice. In addition, the levels of dyslipidemia markers including total cholesterol, triglyceride and low-density lipoprotein cholesterol in the HFD-treated mice were markedly decreased. Further experiments using hepatocytes from mice revealed that HZL significantly attenuated liver injury associated with DM compared with vehicle treatment, as evidenced by lower levels of alanine aminotransferase and aspartate aminotransferase in serum and by lower levels of lipid peroxidation, nitric oxide content and inducible nitric oxide synthase activity in liver tissues. Nuclear factor-κB (NF-κB) and mitogen-associated protein kinase (MAPK) signaling pathways were investigated to elucidate the molecular mechanisms responsible for the protective effects of HZL against diabetic liver injury. The results indicated that HZL inhibited the phosphorylation of p65/NF-κB, MAPK (including p38, JNK and ERK1/2) and activating transcription factor 3 protein expression, with an additional suppression of Bax, cytochrome c, caspase-9 and caspase-3 in the liver tissues of diabetic mice. Taken together, our findings suggest that HZL, which was effective in inhibiting oxidative stress-related pathways may be beneficial for use in the treatment of DM.

Inhibitory Effect of Chemical Constituents Isolated from Artemisia iwayomogi on Polyol Pathway and Simultaneous Quantification of Major Bioactive Compounds

Blocking the polyol pathway plays an important role preventing diabetic complications. Therefore, aldose reductase (AR) and advanced glycation endproducts (AGEs) formation has significant effect on diabetic complications. Artemisia iwayomogi has long been used as treatment of various diseases in Korea. However, no literatures have reported on AR and AGEs formation inhibitory activities of A. iwayomogi. For these reasons, we aimed to assess that A. iwayomogi had potential as anti-diabetic complications agents. We led to isolation of two coumarins (1 and 2), nine flavonoids (3–11), five caffeoylquinic acids (12–16), three diterpene glycosides (17–19), and one phenolic compound (20) from A. iwayomogi. Among them, hispidulin (4), 6-methoxytricin (6), arteanoflavone (7), quercetin-3-gentiobioside (10), 1,3-di-O-caffeoylquinic acid (13), and suavioside A (18) were first reported on the isolation from A. iwayomogi. Not only two coumarins (1 and 2), nine flavonoids (3–11), and five caffeoylquinic acids (12–16) but also extracts showed significant inhibitor on AR and AGEs formation activities. We analyzed contents of major bioactive compounds in Korea's various regions of A. iwayomogi. Overall, we selected Yangyang, Gangwon-do, from June, which contained the highest amounts of bioactive compounds, as suitable areas for cultivating A. iwayomogi as preventive or therapeutic agent in the treatment of diabetic complications.

Dietary flavonoid aglycones and their glycosides: Which show better biological significance?

The dietary flavonoids, especially their glycosides, are the most vital phytochemicals in diets and are of great general interest due to their diverse bioactivity. The natural flavonoids almost all exist as their O-glycoside or C-glycoside forms in plants. In this review, we summarized the existing knowledge on the different biological benefits and pharmacokinetic behaviors between flavonoid aglycones and their glycosides. Due to various conclusions from different flavonoid types and health/disease conditions, it is very difficult to draw general or universally applicable comments regarding the impact of glycosylation on the biological benefits of flavonoids. It seems as though O-glycosylation generally reduces the bioactivity of these compounds - this has been observed for diverse properties including antioxidant activity, antidiabetes activity, anti-inflammation activity, antibacterial, antifungal activity, antitumor activity, anticoagulant activity, antiplatelet activity, antidegranulating activity, antitrypanosomal activity, influenza virus neuraminidase inhibition, aldehyde oxidase inhibition, immunomodulatory, and antitubercular activity. However, O-glycosylation can enhance certain types of biological benefits including anti-HIV activity, tyrosinase inhibition, antirotavirus activity, antistress activity, antiobesity activity, anticholinesterase potential, antiadipogenic activity, and antiallergic activity. However, there is a lack of data for most flavonoids, and their structures vary widely. There is also a profound lack of data on the impact of C-glycosylation on flavonoid biological benefits, although it has been demonstrated that in at least some cases C-glycosylation has positive effects on properties that may be useful in human healthcare such as antioxidant and antidiabetes activity. Furthermore, there is a lack of in vivo data that would make it possible to make broad generalizations concerning the influence of glycosylation on the benefits of flavonoids for human health. It is possible that the effects of glycosylation on flavonoid bioactivity in vitro may differ from that seen in vivo. With in vivo (oral) treatment, flavonoid glycosides showed similar or even higher antidiabetes, anti-inflammatory, antidegranulating, antistress, and antiallergic activity than their flavonoid aglycones. Flavonoid glycosides keep higher plasma levels and have a longer mean residence time than those of aglycones. We should pay more attention to in vivo benefits of flavonoid glycosides, especially C-glycosides.

Chemical Constituents of Smilax china L. Stems and Their Inhibitory Activities against Glycation, Aldose Reductase, α-Glucosidase, and Lipase

The search for natural inhibitors with anti-diabetes properties has gained increasing attention. Among four selected Smilacaceae family plants, Smilax china L. stems (SCS) showed significant in vitro anti-glycation and rat lens aldose reductase inhibitory activities. Bioactivity-guided isolation was performed with SCS and four solvent fractions were obtained, which in turn yielded 10 compounds, including one phenolic acid, three chlorogenic acids, four flavonoids, one stilbene, and one phenylpropanoid glycoside; their structures were elucidated using nuclear magnetic resonance and mass spectrometry. All solvent fractions, isolated compounds, and stem extracts from plants sourced from six different provinces of South Korea were next tested for their inhibitory effects against advanced glycation end products, as well as aldose reductase. α-Glucosidase, and lipase assays were also performed on the fractions and compounds. Since compounds 3, 4, 6, and 8 appeared to be the superior inhibitors among the tested compounds, a comparative study was performed via high-performance liquid chromatography with photodiode array detection using a self-developed analysis method to confirm the relationship between the quantity and bioactivity of the compounds in each extract. The findings of this study demonstrate the potent therapeutic efficacy of SCS and its potential use as a cost-effective natural alternative medicine against type 2 diabetes and its complications.

Phytochemical Analysis of Agrimonia pilosa Ledeb, Its Antioxidant Activity and Aldose Reductase Inhibitory Potential

The aim of this study was to determine aldose reductase (AR) inhibitory activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity of compounds from Agrimonia pilosa Ledeb (AP). We isolated agrimoniin (AM), four flavonoid glucosides and two flavonoid glucuronides from the n-butanol fraction of AP 50% methanol extract. In addition to isolated compounds, the AR-inhibitory activity and the DPPH free radical scavenging activity of catechin, 5-flavonoids, and 4-flavonoid glucosides (known components of AP) against rat lens AR (RLAR) and DPPH assay were measured. AM showed IC₅₀ values of 1.6 and 13.0 μM against RLAR and DPPH scavenging activity, respectively. Additionally, AM, luteolin-7-O-glucuronide (LGN), quercitrin (QU), luteolin (LT) and afzelin (AZ) showed high inhibitory activity against AR and were first observed to decrease sorbitol accumulation in the rat lens under high-sorbitol conditions ex vivo with inhibitory values of 47.6%, 91.8%, 76.9%, 91.8% and 93.2%, respectively. Inhibition of recombinant human AR by AM, LGN and AZ exhibited a noncompetitive inhibition pattern. Based on our results, AP and its constituents may play partial roles in RLAR and oxidative radical inhibition. Our results suggest that AM, LGN, QU, LT and AZ may potentially be used as natural drugs for treating diabetic complications.

Xanthium strumarium as an Inhibitor of α-Glucosidase, Protein Tyrosine Phosphatase 1β, Protein Glycation and ABTS⁺ for Diabetic and Its Complication

Phytochemical investigation of the natural products from Xanthium strumarium led to the isolation of fourteen compounds including seven caffeoylquinic acid (CQA) derivatives. The individual compounds were screened for inhibition of α-glucosidase, protein tyrosine phosphatase 1β (PTP1β), advanced glycation end products (AGEs), and ABTS⁺ radical scavenging activity using in vitro assays. Among the isolated compounds, methyl-3,5-di-caffeoyquinic acid exhibited significant inhibitory activity against α-glucosidase (18.42 μM), PTP1β (1.88 μM), AGEs (82.79 μM), and ABTS⁺ (6.03 μM). This effect was marked compared to that of the positive controls (acarbose 584.79 μM, sumarin 5.51 μM, aminoguanidine 1410.00 μM, and trolox 29.72 μM respectively). In addition, 3,5-di-O-CQA (88.14 μM) and protocatechuic acid (32.93 μM) had a considerable inhibitory effect against α-glucosidase and ABTS⁺. Based on these findings, methyl-3,5-di-caffeoyquinic acid was assumed to be potentially responsible for the anti-diabetic actions of X. strumarium.

Cinnamaldehyde Attenuates Cataractogenesis via Restoration of Hypertension and Oxidative Stress in Fructose-Fed Hypertensive rats

OBJECTIVES

Several studies have revealed that systemic hypertension is strongly associated with cataractogenesis. However, the pathophysiology and treatment is often unclear. In this study, we evaluated the anti-cataractogenic effect of cinnamaldehyde (CA), a natural organic compound, in rats with fructose-induced hypertension.

METHODS

The rats were divided into six groups. For six weeks, the normal group received a suspension of 0.5% carboxy methyl cellulose (10 mL/kg/day, p.o.) while five other groups received a 10% (w/v) fructose solution in their drinking water to induce hypertension. By the end of the third week hypertension had been induced in all the animals receiving fructose. From the beginning of the fourth week to the end of the sixth week, one of those five groups (control) continued to receive only 10% (w/v) fructose solution, one group (standard) received ramipril (1 mg/kg/day, p.o.) plus 10% (w/v) fructose solution, and three groups (experimental) received CA at doses of 20, 30, and 40 mg/kg/day p.o., plus 10% (w/v) fructose solution. Blood pressure was measured weekly using a non-invasive blood pressure apparatus. After six weeks, the animals were sacrificed, and the anti-cataractogenic effects on the eye lenses were evaluated.

RESULTS

Administration of fructose elevated both the systolic and the diastolic blood pressures, which were significantly reduced by CA at all dose levels. In the control group, a significant increase in the malonaldehyde (MDA) level and decreases in the total protein, Ca(2+)adenosine triphosphate (ATP)ase activity, glutathione peroxidase, catalase, superoxide dismutase and glutathione levels, as compared to the normal group, were observed. Administration of CA at all doses significantly restored the enzymatic, non-enzymatic, antioxidants, total protein, and Ca(2+)ATPase levels, but decreased the MDA level, as compared to the control group.

CONCLUSION

The present study revealed that CA modulated the antioxidant parameters of the serum and lens homogenates in hypertension-induced cataractogenic animals.

Fabrication of Apigenin loaded gellan gum-chitosan hydrogels (GGCH-HGs) for effective diabetic wound healing

The Apigenin (APN) was isolated from ethanolic extract of M. alba leaves and screened by in-vivo wound models (Diabetic and Dead space) in rats. Apigenin loaded hydrogel (HGs) was prepared using gellan gum-chitosan (GGCH) with PEG as a cross linker and characterized for various parameter like AFM, swelling property, entrapment efficiency and drug release. Further performance of hydrogel was evaluated by wound healing activity tested against wound contraction, collagen content, dried granuloma weights and antioxidant activity. The percent entrapment efficiency of optimized hydrogel found to be 87.15±1.20. APN loaded GGCH-HGs were able to release 96.11% APN in 24h. The level of superoxide dismutase (SOD) and catalase were found increased significantly in granuloma tissue of APN treated group. APN GGCH-HGs found higher wound healing effect in diabetic as well as normal wound tissues with significant antioxidant activity. Results proven the utility of prepared hydrogel (APN loaded GGCH-HGs) seems to be highly suitable for wound healing due to its unique properties of biocompatibility, biodegradability, moist nature and antioxidant effectiveness.

Esculetin, a Coumarin Derivative, Inhibits Aldose Reductase Activity in vitro and Cataractogenesis in Galactose-Fed Rats

Naturally occurring coumarin compounds have received substantial attention due to their pharmaceutical effects. Esculetin is a coumarin derivative and a polyphenol compound that is used in a variety of therapeutic and pharmacological strategies. However, its effect on aldose reductase activity remains poorly understood. In this study, the potential beneficial effects of esculetin on lenticular aldose reductase were investigated in galactose-fed (GAL) rats, an animal model of sugar cataracts. Cataracts were induced in Sprague-Dawley (SD) rats via a 50% galactose diet for 2 weeks, and groups of GAL rats were orally treated with esculetin (10 or 50 mg/kg body weight). In vehicle-treated GAL rats, lens opacification was observed, and swelling and membrane rupture of the lens fiber cells were increased. Additionally, aldose reductase was highly expressed in the lens epithelium and superficial cortical fibers during cataract development in the GAL rats. Esculetin reduced rat lens aldose reductase (RLAR) activity in vitro, and esculetin treatment significantly inhibited lens opacity, as well as morphological alterations, such as swelling, vacuolation and liquefaction of lens fibers, via the inhibition of aldose reductase in the GAL rats. These results indicate that esculetin is a useful treatment for galactose-induced cataracts.

Simultaneous quantification and validation of new peroxynitrite scavengers from Artemisia iwayomogi

CONTEXT

Artemisia iwayomogi Kitamura (Compositae) has been very widely used for the treatment of acute or chronic hepatitis, jaundice, and gastritis. In the course of our continuing efforts to identify and quantify peroxynitrite scavengers from Compositae plants, A. iwayomogi was used in this study.

OBJECTIVE

The present study was aimed to identify and quantify the peroxynitrite scavengers of A. iwayomogi.

MATERIALS AND METHODS

Silica gel and ODS were used for column chromatography. The isolated compounds were quantified using an HPLC equipped with a Capcell Pak C18 column (5 μm, 250 mm × 4.6 mm i.d.), and the method was validated for the quality control. Peroxynitrite (ONOO(-))-scavenging activities of the compounds and extracts were evaluated on the measurement of highly fluorescent rhodamine 123 converted from non-fluorescent dihydrorhodamine (DHR)-123 under the presence of peroxynitrite.

RESULTS

Based on the spectroscopic evidences, a new compound, 2"-O-caffeoylrutin (2"-O-trans-caffeic acid ester of quercetin 3-O-α-L-rhamnopyranosyl(1 → 6)-β-D-glucopyranoside) was isolated and determined together with patuletin 3-O-glucoside, scopolin, scopoletin, rutin, 3,4-dicaffeoylquinic acid, and chlorogenic acid. All of them were potent peroxynitrite scavengers (IC50 ≤ 1.88 μg/mL).

DISCUSSION AND CONCLUSION

The peroxynitrite scavengers were mainly distributed in the EtOAc fraction rather than the ether and BuOH fractions. The 70% MeOH extract exhibited a high peroxynitrite-scavenging activity. Through the validation, the present HPLC method was verified to be sufficiently sensitive, accurate, precise, and stable. Therefore, this method can be used for the quality control of A. iwayomogi.

The multi-targets integrated fingerprinting for screening anti-diabetic compounds from a Chinese medicine Jinqi Jiangtang Tablet

ETHNOPHARMACOLOGICAL RELEVANCE

Jinqi Jiangtang Tablet is a traditional Chinese anti-diabetic formula containing three ingredients: Coptis chinensis Franch. (dried rhizome of C. chinensis Franch., Coptis deltoidea C. Y. Cheng et Hsiao and Coptis teeta Wall.), Astragalus membranaceus (Fisch.) Bunge. (dried root of A. membranaceus (Fisch.) Bge. var. mongholicus (Bge. ) Hsiao and A. membranaceus (Fisch.) Bge. ) and Lonicera japonica Thunb. (dried alabastrum or with nascent flowers of L. japonica Thunb. ). Free radicals, α-glucosidase, α-amylase, aldose reductase and lipase are different targets related with diabetes. However, there are no chromatographic methods employed in screening the anti-diabetic compounds from natural products basing on these targets simultaneously. The present study was aimed at the establishment of a multi-targets integrated fingerprinting to clarify the possible mechanism of the action of Traditional Chinese Medicines which simultaneously contained multiple chemical characteristics and effects of constitutions.

MATERIALS AND METHODS

The multi-targets integrated fingerprinting was developed and validated to screen anti-diabetic compounds from natural products by using ultra-high-performance liquid chromatography/quadruple-time-of-flight mass spectrometry, fraction collector and microplate reader. Ultra performance liquid chromatography was employed to separate the components in Jinqi Jiangtang Tablet, which were identified by quadruple-time-of-flight mass spectrometry to acquire their structural information and collected by the fraction collector. Finally the active fractions were tested for scavenging 1, 1-diphenyl-2-picrylhydrazyl radical and inhibition of α-glucosidase, α-amylase, aldose reductase, and lipase activities in vitro by microplate reader.

RESULTS

Our tests revealed that the Jinqi Jiangtang Tablet showed inhibitory activity against α-glucosidase, α-amylase, aldose reductase and lipase with IC50 values of 0.80 ± 0.02 mg/mL, 1.28 ± 0.13 mg/mL, 0.80 ± 0.02 mg/mL, 1.90 ± 0.18 mg/mL respectively and the scavenging activity with IC50 value of 1.71 ± 0.178 mg/mL. The bioactive fractions were identified to be alkaloids, flavonoids and phenolic acids. The phenolic acids possessed antioxidant activities, namely the scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl rull;). The alkaloids exhibited inhibitory activity against α-glucosidase, aldose reductase, α-amylase, and lipase. The flavonoids also showed mild inhibition on α-glucosidase, aldose reductase, α-amylase and lipase.

CONCLUSIONS

The results demonstrate that Jinqi Jiangtang Tablet can scavenge free radicals and inhibit α-glucosidase, aldose reductase, α-amylase and lipase, which may be the possible mechanism of action of Jinqi Jiangtang Tablet for the treatment of diabetes and associated complications. Compared with conventional chromatographic separation and activity assays, the multi-targets integrated fingerprinting, which simultaneously contains the chemical characteristics and multiple effects of constitutions could comprehensively and properly reveal the activity of Jinqi Jiangtang Tablet. The results also show that the multi-targets integrated fingerprinting is a novel and powerful tool for screening and identifying active ingredients from Traditional Chinese Medicines.

Diabetes mellitus: an overview on its pharmacological aspects and reported medicinal plants having antidiabetic activity

Diabetes mellitus is not a single disease but is a group of metabolic disorders affecting a huge number of population in the world. It is mainly characterized by chronic hyperglycemia, resulting from defects in insulin secretion or insulin action. It is predicated that the number of diabetes person in the world could reach upto 366 million by the year 2030. Even though the cases of diabetes are increasing day by day, except insulin and oral hypoglycemic drugs no other way of treatment has been successfully developed so far. Thus, the objective of the present review is to provide an insight over the pathophysiological and etiological aspects of diabetes mellitus along with the remedies available for this metabolic disorder. The review also contains brief idea about diabetes mellitus and the experimental screening model with their relevant mechanism and significance mainly used nowadays. Alloxan and streptozotocin are mainly used for evaluating the antidiabetic activity of a particular drug. This review contain list of medicinal plants which have been tested for their antidiabetic activity in the alloxan induced diabetic rat model. From the available data in the literature, it was found that plant having antidiabetic activity is mainly due to the presence of the secondary metabolite. Thus, the information provided in this review will help the researchers for the development of an alternative methods rather than insulin and oral hypoglycemic agents for the treatment of diabetes mellitus, which will minimize the complication associated with the diabetes and related disorder.

Skin Regeneration Effect and Chemical Composition of Essential Oil from Artemisia montana

Artemisia montana Pampan (Compositae) (AMP) contains various compounds, including phenolic acids, alkaloids, and essential oil. It has been widely used in oriental medicine due to a variety of biological effects. However, the biological activity of the essential oil from AMP (AMPEO) on skin has not been investigated. In the present study, AMPEO was evaluated for its composition and its effect on cellular events (migration and proliferation) related to skin regeneration using normal human keratinocytes (HaCats). AMPEO, which was extracted by steam distillation, contained 42 components. AMPEO increased proliferation in HaCats in a dose-dependent manner (EC 50, 8.5 ng/mL) and did not affect migration. AMPEO also enhanced the phosphorylation of Akt and ERK 1/2 and induced the synthesis of type IV collagen, but not type I collagen in HaCats. In addition, AMPEO promoted wound closure in the dorsal side skin of rat tail. These results demonstrated that AMPEO extracted by steam distillation induced proliferation and synthesis of type IV collagen in human skin keratinocytes, and may thereby exert positive effects on skin regeneration and wound healing in human skin.

Purification and characterization of flavonoids from the leaves of Zanthoxylum bungeanum and correlation between their structure and antioxidant activity

Nine flavonoids were isolated and characterized from the leaves of Zanthoxylum bungeanum. Their structures were elucidated by spectroscopic techniques as quercetin (1), afzelin (2), quercitrin (3), trifolin (4), quercetin-3-O-β-D-glucoside (5), isorhamnetin 3-O-α-L-rhamnoside (6), hyperoside (7), vitexin (8) and rutin (9). All compounds were isolated from the leaves of Z. bungeanum for the first time. Five compounds (2, 4, 5, 6 and 8) were found for the first time in the genus Zanthoxylum. To learn the mechanisms underlying its health benefits, in vitro (DPPH, ABTS, FRAP and lipid peroxidation inhibition assays) and in vivo (protective effect on Escherichia coli under peroxide stress) antioxidant activities of the nine flavonoids were measured. Quercetin and quercetin glycosides (compounds 1, 3, 5, 7, 9) showed the highest antioxidant activity. Structure-activity relationships indicated that the -OH in 4′ position on the B ring and the -OH in 7 position on the A ring possessed high antioxidant activity; B ring and/or A ring with adjacent -OH groups could greatly increase their antioxidant ability. Also, due to the different structures of various flavonoids, they will certainly exhibit different antioxidant capacity when the reactions occur in solution or in oil-in-water emulsion. These findings suggest that Z. bungeanum leaves may have health benefits when consumed. It could become a useful supplement for pharmaceutical products and functional food ingredients in both nutraceutical and food industries as a potential source of natural antioxidants.