Bioactive compounds from Cornus officinalis fruits and their effects on diabetic nephropathy

Evaluation of biosynthesis parameters, stability and biological activities of silver nanoparticles synthesized by Cornus Officinalis extract under 365 nm UV radiation

Since silver nanoparticles (AgNPs) synthesized by using plant extracts revealed varied biological activities, the green synthesis of AgNPs has attracted considerable attention. Although the green synthesis of AgNPs have been accomplished by using the extracts of Cornus Officinalis, which is a traditional Chinese medicine and exhibits a wide spectrum of phytochemicals. The effects of biosynthesis parameters on reducing reaction, stability and more broad biological activities of so-prepared AgNPs did not been evaluated. In this paper, we firstly assessed the effects of UV radiation, pH, material proportion and radiation times on the green synthesis of AgNPs under 365 nm UV radiation by UV-visible spectrum and dynamic light scattering (DLS) analysis. The results showed that UV radiation could accelerate the formation of AgNPs and influence the average size below pH 7.0, and the size of so-prepared AgNPs were sensitive to the pH and material proportion, but no obvious changes to UV radiation times, offering a size-controlled synthetic method for AgNPs. The further X-ray diffraction (XRD), transmission electron microscopy (TEM) and DLS studies showed AgNPs synthesized at pH 7.0, extract: AgNO₃ = 1 : 1 and after 4 h UV radiation were a face-centered cubic (fcc) structure and both spherical and polygonal in shape with average particle size of 64.5 ± 0.3 nm existed in a monodispersed form. Subsquently, the stability of AgNPs was analyzed by zeta potential (-24.8 mV) and the average size measurement after 30 days storage (63.3 ± 0.4 nm), revealing a high degree of stability. Lastly, the investigation of biological activities showed that the biosynthesized AgNPs had potent antioxidant activity, antimicrobial activity against both S. aureus and E. coli as well as anticancer activity against HCT116 and HepG2 cell lines but negligible cytotoxicity against SW620. And the internalization of biosynthesized AgNPs inside the bacterial cell was evaluated by flow cytometric analysis, where the SSC values have significant increase after treating with nanoparticles. These results confirmed that the biosynthesis parameters on the green synthesis of AgNPs by using Cornus Officinalis extract also played pivotal roles and so-prepared AgNPs would be useful for the development of new alternative antioxidant, antimicrobial and anticancer agents in biomedicine.

Loganin and catalpol exert cooperative ameliorating effects on podocyte apoptosis upon diabetic nephropathy by targeting AGEs-RAGE signaling

BACKGROUND/AIMS

Rehmanniae Radix (RR) and Cornus officinalis (CO) are a typical herbal pair used to treat diabetic nephropathy (DN) in clinical practice. DN can be effectively treated by catalpol (Cat) and loganin (Log), the main active components of RR and CO respectively, through combating apoptosis, oxidative stress and inflammation. Herein, a spontaneous DN and podocyte injury model induced by advanced glycation end products (AGEs), i.e. KK-Ay mice, was used to explore the cooperative effects of Log and Cat on DN and the mechanism targeting the AGEs-RAGE (receptor for AGE) pathway.

METHODS AND KEY FINDINGS

Log and Cat alone or in combination mitigated diabetic symptoms, decreased the level of fasting blood glucose, and increased that of serum insulin. The two drugs alone or in combination protected renal function from damage, prevented extracellular matrix hyperplasia and glycogen deposition, as well as alleviated the loss of podocytes detected by histological assay and immunohistochemistry. Flow cytometry revealed that Log and Cat alone or in combination relieved the apoptosis of AGEs-induced podocytes in vitro. Silencing RAGE by RNA interference played a protective role in podocyte apoptosis, whereas overexpression of it worked oppositely. Western blot exhibited that Log and Cat alone or in combination inhibited the activation of RAGE/p38 MAPK/p65 NF-κB and RAGE/Nox4/p65 NF-κB pathways in podocytes. The inhibitory effects of drug combination were more evident than those of individual treatments.

SIGNIFICANCE

Log and Cat cooperatively resisted the apoptosis of podocytes upon DN by targeting AGEs-RAGE and its downstream pathways p38 MAPK and Nox4.

Kampo medicines, Rokumigan, Hachimijiogan, and Goshajinkigan, significantly inhibit glucagon-induced CREB activation

The pathophysiology of type 2 diabetes mellitus (T2DM) is characterized by not only insulin resistance, but also the abnormal regulation of glucagon secretion, suggesting that antagonizing the glucagon-induced signaling pathway has therapeutic potential in the treatment of T2DM. Although various Kampo medicines (traditional herbal medicines) are often utilized to ameliorate the symptoms of T2DM, their effects on glucagon signaling have not yet been clarified. In the present study, we examined the effects of nine types of representative Kampo formulations prescribed for T2DM on glucagon-induced CREB activation in HEK293T cells stably expressing glucagon receptor (Gcgr) and a hepatic cell line HepG2. Among these Kampo medicines, Rokumigan, Hachimijiogan, and Goshajinkigan significantly suppressed the glucagon-induced transactivation of the cAMP-responsive element (CRE)-binding protein (CREB) by inhibiting its interaction with CREB-binding protein (CBP), which led to a reduction in the expression of phosphoenolpyruvate carboxykinase (PEPCK) mRNA. Furthermore, among the crude drugs commonly contained in these three Kampo medicines, Rehmannia Root (Jio), Moutan Bark (Botampi), and Cornus Fruit (Shanzhuyu) exerted inhibitory effects on glucagon-induced CREB activation. Collectively, the present results provide a novel mechanism, the inhibition of glucagon signaling, by which Rokumigan, Hachimijiogan, and Goshajinkigan improve the symptoms of T2DM.

Undescribed morroniside-like secoiridoid diglycosides with α-glucosidase inhibitory activity from Corni Fructus

Corni Fructus, also known as the fruit of Cornus officinalis Sieb. et Zucc., has long been used as a traditional Chinese medicine and is widely consumed as a nutritional food in the form of function drink and wine. Recently, Corni Fructus has attracted considerable interest because of its anti-diabetic effects. A systematic phytochemical investigation of Corni Fructus was performed to find anti-diabetic components, which led to the isolation of 10 unreported iridoid glycosides, cornusdiglycosides A-J (1-8, 9a/9b and 10a/10b). Their chemical structures were determined through spectroscopic analysis (ultraviolet [UV], infrared [IR], high-resolution electrospray ionisation mass spectroscopy [HRESIMS], one-dimensional [1D] and two-dimensional [2D] nuclear magnetic resonance [NMR]). Such morroniside-type diglycosides were first reported from natural sources, and all isolates were evaluated for α-glucosidase inhibitory activity. The results showed that all compounds (1-10) exhibited α-glucosidase (from Saccharomyces cerevisiae) inhibitory activities with IC₅₀ values ranging from 78.9 ± 4.09 to 162.2 ± 9.17 μM, whereas acarbose, the positive control, displayed α-glucosidase inhibitory activity with IC₅₀ value of 118.9 ± 7.89 μM.

Extract of Cornus officinalis Protects Keratinocytes from Particulate Matter-induced Oxidative Stress

The skin is one of the large organs in the human body and the most exposed to outdoor contaminants such as particulate matter < 2.5 µm (PM_2.5). Recently, we reported that PM_2.5 induced cellular macromolecule disruption of lipids, proteins, and DNA, via reactive oxygen species, eventually causing cellular apoptosis of human keratinocytes. In this study, the ethanol extract of Cornus officinalis fruit (EECF) showed anti-oxidant effect against PM_2.5-induced cellular oxidative stress. EECF protected cells against PM_2.5-induced DNA damage, lipid peroxidation, and protein carbonylation. PM_2.5 up-regulated intracellular and mitochondrial Ca²⁺ levels excessively, which led to mitochondrial depolarization and cellular apoptosis. However, EECF suppressed the PM_2.5-induced excessive Ca²⁺ accumulation and inhibited apoptosis. The data confirmed that EECF greatly protected human HaCaT keratinocytes from PM_2.5-induced oxidative stress.

Compositional analysis and biological characterization of Cornus officinalis on human 1.1B4 pancreatic β cells

Type 1 diabetes (T1D) is an autoimmune disease resulting from the loss of pancreatic β cells and subsequent insulin production. Novel interventional therapies are urgently needed that can protect existing β cells from cytokine-induced death and enhance their function before symptomatic onset. Our initial evidence is suggesting that bioactive ingredients within Cornus officinalis (CO) may be able to serve in this function. CO has been extensively used in Traditional Chinese Medicine (TCM) and reported to possess both anti-inflammatory and pro-metabolic effects. We hypothesize that CO treatment may provide a future potential candidate for interventional therapy for early stage T1D prior to significant β cell loss. Our data demonstrated that CO can inhibit cytokine-mediated β cell death, increase cell viability and oxidative capacity, and increase expression of NFATC2 (Nuclear Factor of Activated T Cells, Cytoplasmic 2). We have also profiled the bioactive components in CO from multiple sources by HPLC/MS (High Performance Liquid Chromatography/Mass Spectrometry) analysis. Altogether, CO significantly increases the energy metabolism of β cells while inducing the NFAT pathway to signal for increased proliferation and endocrine function.

Application of Traditional Chinese Herbal Medicine By-products as Dietary Feed Supplements and Antibiotic Replacements in Animal Production

BACKGROUND

Misuse of synthetic antibiotics in livestock leads to the transfer of antibiotic resistant pathogens into humans and deposits toxic residues in meat and milk. There is therefore an urgent need for safe and viable alternative approaches to improve the nutrition and wellbeing of farm animals. An alternative source that has been widely exploited is Traditional Chinese Herbal Medicine (TCHM). These herbs contain several but less toxic bioactive compounds which are generally regarded as biodegradable. Recently, advances in the knowledge of the importance of TCHM have led to a rapid increase in its production and hence, increasing the amount of by-products generated. Such by-products have become a serious environmental challenge because producers regard them as industrial waste and discard them directly. This review summarizes scientific findings on the bioactive compounds in TCHM and TCHM by-products, discusses functional dietary patterns and outlines challenges that may hinder full utilization of TCHM by-products in animal production.

METHODS

Information for this review was obtained through scientific databases and websites such as Pubmed and Google scholar from 2004 to 2017 using experimental studies on bioactive compounds in TCHM and their effects in animal production.

RESULTS

Studies have shown that TCHM by-products contain high amounts of bioactive compounds which confer several nutritional and health benefits to animals and thus could be incorporated as feed additives.

CONCLUSION

The findings for this review indicate that TCHM by-products apart from being a good alternative for synthetic antibiotics could also minimize the current environmental challenges associated with its disposal.

Therapeutic Potential of Iridoid Derivatives: Patent Review

Iridoids belong to a family of monoterpenoids comprising the cyclopentan[c]-pyran system; this class of compounds offers a wide range of biological effects, namely antileishmanial, anticancer, antiplasmodial, and anti-inflammatory potency. To date, a large number of biologically active iridoid derivatives have been reported from various plant families, including Rubiaceae, Plantaginaceae, Scrophulariaceae, and Verbenaceae. Furthermore, iridoids have the potential to form conjugates with other anticancer, antidiabetic, antileishmanial, and antimalarial drugs which synergistically have the potential to increase their effects. Additionally, future research should focus on the synthesis of halo analogs as well as preparing homo dimers or heterodimers of iridoids, since these might quite conceivably possess an increased bioactivity.

Simultaneous high-performance liquid chromatography with tandem mass spectrometry quantification of six bioactive components in rat plasma after oral administration of Yougui pill

Yougui pills are a classic Chinese medicine that shows significant effects on nerve regeneration and neuroprotection in modern pharmacological studies. With a complex formula, Yougui pills have faced significant challenges in the fields of bioanalysis and pharmacokinetics in animals and human studies. In the present study, a specific and accurate high-performance liquid chromatography with tandem mass spectrometry method was developed and validated for the quantitative determination of the six bioactive components in rat plasma after oral administration of Yougui pills. Chromatographic separation was performed on a C18 column with a gradient elution system. Samples were analysed using positive ion mode with multiple reaction monitoring mode. The assay showed good linearity for all six bioactive components in the dynamic range of 0.50 to 50 ng/mL with acceptable intra- and inter-batch accuracy and precision. The lower limits of quantification were 0.50 ng/mL for all six bioactive components. The method was successfully applied to rat pharmacokinetics after oral administration of Yougui pills. All six bioactive components were detected in rat plasma, including songorine, benzoylhypaconitine, benzoylmesaconitine, neoline, karacoline, and sweroside, while some other target compounds were not detected, such as rhmannioside A, loganin, and cornuside I. After oral administration of Yougui pills at a dose of 2500 mg/kg, all six bioactive components were rapidly absorbed, resulting in t_max values less than 1 h and relative lower C_max values. The t_1/2 values for songorine, benzoylhypaconitine, benzoylmesaconitine, neoline, karacoline, and sweroside were calculated to be 2.62 ± 0.67, 2.11 ± 0.45, 1.94 ± 0.35, 1.88 ± 0.31, 2.07 ± 0.44, and 1.59 ± 0.30 h, which indicated that Yougui pills should be taken in multiple oral doses over a relatively short period.

The natural drug DIAVIT is protective in a type II mouse model of diabetic nephropathy

There is evidence to suggest that abnormal angiogenesis, inflammation, and fibrosis drive diabetic nephropathy (DN). However, there is no specific treatment to counteract these processes. We aimed to determine whether DIAVIT, a natural Vaccinium myrtillus (blueberry) and Hippophae Rhamnoides (sea buckthorn) extract, is protective in a model of type II DN. Diabetic db/db mice were administered DIAVIT in their drinking water for 14 weeks. We assessed the functional, structural, and ultra-structural phenotype of three experimental groups (lean+vehicle, db/db+vehicle, db/db+DIAVIT). We also investigated the angiogenic and fibrotic pathways involved in the mechanism of action of DIAVIT. Diabetic db/db mice developed hyperglycaemia, albuminuria, and an increased glomerular water permeability; the latter two were prevented by DIAVIT. db/db mice developed fibrotic glomeruli, endothelial insult, and glomerular ultra-structural changes, which were not present in DIAVIT-treated mice. Vascular endothelial growth factor A (VEGF-A) splicing was altered in the db/db kidney cortex, increasing the pro-angiogenic VEGF-A₁₆₅ relative to the anti-angiogenic VEGF-A₁₆₅b. This was partially prevented with DIAVIT treatment. Delphinidin, an anthocyanin abundant in DIAVIT, increased the VEGF-A₁₆₅b expression relative to total VEGF-A₁₆₅ in cultured podocytes through phosphorylation of the splice factor SRSF6. DIAVIT, in particular delphinidin, alters VEGF-A splicing in type II DN, rescuing the DN phenotype. This study highlights the therapeutic potential of natural drugs in DN through the manipulation of gene splicing and expression.

New Iridoid Derivatives from the Fruits of Cornus officinalis and Their Neuroprotective Activities

Three previously undescribed iridoids, cornusfurals A–C, were isolated from the ethanolic extracts of fruits of Cornus officinalis. Their structures were elucidated by spectroscopic methods, including one-dimensional and two-dimensional nuclear magnetic resonance, ultraviolet spectroscopy, infrared spectroscopy, and mass spectrometry. The neuroprotective activity was evaluated by measuring corticosterone-induced damage in PC12 cells. The results showed that cornusfural B decreased corticosterone-induced PC12 cell damage compared with that in model cells.

Effect of Korean Herbal Formula (Modified Ojayeonjonghwan) on Androgen Receptor Expression in an Aging Rat Model of Late Onset Hypogonadism

Purpose

Testosterone replacement therapy is an effective treatment for late-onset hypogonadism (LOH) despite a few contraindications and side-effects. The aim of this study was to determine whether modified Ojayeonjonghwan (KH-204, Korean herbal formula) improved LOH. KH-204 is a strong antioxidant herbal formula. We evaluated the effect of Korean herbal prescription on androgen receptor (AR) expression in an aged rat model of LOH.

Materials and Methods

Eighteen-month-old rats were used as aged LOH rat models. Eighteen Sprague-Dawley rats were randomly divided into three equal groups of six animals each and treated with one of the following: 1) normal control group (oral administration with distilled water, n=6), 2) KH-204 200 group (oral administration with 200 mg/kg of KH-204, n=6), and 3) KH-204 400 group (oral administration with 400 mg/kg of KH-204, n=6). After four weeks of treatment (once daily, distilled water or KH-204), serum testosterone levels, changes in testicular and epididymal weight, Western blotting analysis of AR expression and measurement of oxidative stress were examined.

Results

Treatment with the herbal formulation KH-204 200 mg/kg and 400 mg/kg (1) increased the weights of testis and epididymis; (2) increased the level of serum testosterone; (3) increased the level of superoxide dismutase and reduced the level of 8-hydroxy-20-deoxyguanosine; and (4) upregulated AR expression in testicular tissue.

Conclusions

KH-204 might be an effective alternative for LOH. It improves antioxidant mechanisms and increases testicular AR expression without side-effects.

Elucidation of the Intestinal Absorption Mechanism of Loganin in the Human Intestinal Caco-2 Cell Model

Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (PappAB) of loganin, which ranged from 12.17 to 14.78 × 10-6cm/s, was high at four tested concentrations (5, 20, 40, and 80μM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.

Corn silk (Zea mays L.), a source of natural antioxidants with α-amylase, α-glucosidase, advanced glycation and diabetic nephropathy inhibitory activities

The oxidative stress plays a critical role in the progression of diabetes mellitus (DM) and its complications. Corn silk is a traditional medicine used to treat DM. The aim of this study is to investigate the antioxidant capacity of corn silk, as well as its inhibitory potential on DM and diabetic nephropathy (DN). The ethanol extract of corn silk (CS) was liquid-liquid fractionated to get petroleum ether fraction (PCS), ethyl acetate fraction (ECS), n-butanol fraction (BCS) and water fraction (WCS). The Folin-Ciocalteu and AlCl₃ assay showed that silk corn contained considerable amount of phenolics and flavonoids, ECS and BCS were the two phenolic-enriched fractions with highest TPC and TFC values. The ECS and BCS showed the highest total antioxidant activity and reducing power, as well as the strongest scavenging activity against DPPH and hydroxyl radicals, compared to CS and other fractions. The ECS and BCS displayed appreciable anti-hyperglycaemic effect indicated by the significant inhibition on α-amylase and α-glucosidase in enzymatic assays. In BSA-glucose model, ECS and BCS effectively inhibited the formation of advanced glycation end products (AGEs). In addition, the anti-diabetic nephropathy activity assay displayed that CS, ECS and BCS significantly inhibited the production of Col IV, FN and IL-6 in high-glucose stimulated mesangial cells at 200 μg/mL. These findings suggested the antioxidant activities of corn silk could contribute, at least in part, to its traditionally claimed therapeutic benefits on DM and DN. The phenolic-enriched CS fractions could be considered as a source of natural antioxidants and further developed for the prevention and treatment of DM and its complications including DN.

Cornus mas and Cornus Officinalis-Analogies and Differences of Two Medicinal Plants Traditionally Used

Among 65 species belonging to the genus Cornus only two, Cornus mas L. and Cornus officinalis Sieb. et Zucc. (Cornaceae), have been traditionally used since ancient times. Cornus mas (cornelian cherry) is native to southern Europe and southwest Asia, whereas C. officinalis (Asiatic dogwood, cornel dogwood) is a deciduous tree distributed in eastern Asia, mainly in China, as well as Korea and Japan. Based on the different geographic distribution of the closely related species but clearly distinct taxa, the ethnopharmacological use of C. mas and C. officinalis seems to be independently originated. Many reports on the quality of C. mas fruits were performed due to their value as edible fruits, and few reports compared their physicochemical properties with other edible fruits. However, the detailed phytochemical profiles of C. mas and C. officinalis, in particular fruits, have never been compared. The aim of this review was highlighting the similarities and differences of phytochemicals found in fruits of C. mas and C. officinalis in relation to their biological effects as well as compare the therapeutic use of fruits from both traditional species. The fruits of C. mas and C. officinalis are characterized by the presence of secondary metabolites, in particular iridoids, anthocyanins, phenolic acids and flavonoids. However, much more not widely known iridoids, such as morroniside, as well as tannins were detected particularly in fruits of C. officinalis. The referred studies of biological activity of both species indicate their antidiabetic and hepatoprotective properties. Based on the available reports antihyperlipidemic and anticoagulant activity seems to be unique for extracts of C. mas fruits, whereas antiosteoporotic and immunomodulatory activities were assigned to preparations of C. officinalis fruits. In conclusion, the comparison of phytochemical composition of fruits from both species revealed a wide range of similarities as well as some constituents unique for cornelian cherry or Asiatic dogwood. Thus, these phytochemicals are considered the important factor determining the biological activity and justifying the use of C. mas and C. officinalis in the traditional European and Asiatic medicine.

Hypoglycemic, hypolipidemic and antioxidant effects of iridoid glycosides extracted from Corni fructus: possible involvement of the PI3K-Akt/PKB signaling pathway

Iridoid glycosides (CIG) are the major component of Corni fructus. In this work, we researched the antioxidative, hypoglycemic and lowering blood lipids effects of CIG on diabetic mice induced by a high-fat diet (HFD) and streptozotocin (STZ). Furthermore, to investigate the molecular mechanism of action, the phosphorylation and protein expression of phosphoinositide 3-kinase (PI3K) and its downstream proteins, such as insulin receptor (INSR), protein kinase B (Akt/PKB) and glucose transporter 4 (GLUT4) have been detected. The results showed that CIG significantly improved oral glucose tolerance in diabetic mice. Biochemical indices also revealed that CIG had a positive effect on lipid metabolism and oxidative stress. In addition, CIG can significantly enhance the expression level of the PI3K-Akt/PKB pathway related proteins in skeletal muscle, which is the key pathway of insulin metabolism. These findings show that CIG can improve the hyperglycemia and hyperlipidemia of HFD-STZ-induced diabetic mice through the PI3K-Akt/PKB signaling pathway, and CIG might be a potential medicine or functional food for type 2 diabetes mellitus remedies.

Corni Fructus attenuates testosterone-induced benign prostatic hyperplasia by suppressing 5α-reductase and androgen receptor expression in rats

BACKGROUND/OBJECTIVES

Benign prostatic hypertrophy (BPH) is a major cause of abnormal overgrowth of the prostate mainly in the elderly. Corni Fructus has been reported to be effective in the prevention and treatment of various diseases because of its strong antioxidant effect, but its efficacy against BPH is not yet known. This study was designed to evaluate the therapeutic efficacy of Corni Fructus water extract (CF) in testosterone-induced BPH rats.

MATERIALS/METHODS

To induce BPH, rats were intraperitoneal injected with testosterone propionate (TP). Rats in the treatment group were orally administered with CF with TP injection, and finasteride, which is a selective inhibitor of 5α-reductase type 2, was used as a positive control.

RESULTS

Our results showed that the increased prostate weight and histopathological changes in BPH model rats were suppressed by CF treatment. CF, similar to the finasteride-treated group, decreased the levels of testosterone and dihydrotestosterone by TP treatment in the serum, and it also reduced 5α-reductase expression and concentration in prostate tissue and serum, respectively. In addition, CF significantly blocked the expression of the androgen receptor (AR), AR co-activators, and proliferating cell nuclear antigen in BPH rats, and this blocking was associated with a decrease in prostate-specific antigen levels in serum and prostate tissue.

CONCLUSIONS

These results suggest that CF may weaken the BPH status through the inactivation of at least 5α-reductase and AR activity and may be useful for the clinical treatment of BPH.

Corni Fructus: a review of chemical constituents and pharmacological activities

Cornus officinalis Sieb. et Zucc. is part of the genus Cornus of the family Cornaceae. Ripening and dry fruits (Corni Fructus) are recognized as an essential herb medicine in the traditional Chinese medicine (TCM) and have been widely used for over 2000 years. This review provides a comprehensive summary of Corni Fructus (CF), including the botany, phytochemistry, traditional use, and current pharmacological activities. According to the basic theory of TCM, CF usually participates in various Chinese medicinal formulae to exert the essential roles in replenishing liver and kidney, arresting seminal emission and sweat. Based on modern pharmacological studies, about 90 compounds have been isolated and identified from CF. In vivo and in vitro experimental studies indicate that CF exhibits extensive pharmacological activities including hypoglycemic, antioxidant, anti-inflammatory, anticancer, neuroprotective, hepatoprotective, and nephroprotective activities. However, only about 18% of chemical constituents in CF were tested. It means the potential pharmacological activities and clinical values of CF need to be further investigated.

Kaempferol attenuates hyperglycemia-induced cardiac injuries by inhibiting inflammatory responses and oxidative stress

PURPOSE

Suppression of inflammation and oxidative stress is an attractive strategy to against diabetic cardiomyopathy (DCM). Kaempferol (KPF) exerts both anti-inflammatory and antioxidant pharmacological properties. However, little is known about the effect of KPF on protecting myocardial injury in diabetes. The present study aimed to investigate the effect of KPF on DCM and underlying mechanism.

METHODS

Anti-inflammation and anti-oxidative stress activities of KPF were evaluated in H9c2 cells or primary cardiomyocytes by real-time quantitate PCR, immunoblotting, immunofluorescence, ELISA, and FACS. Streptozotocin (STZ)-induced type 1 diabetes mellitus mice were constructed. Corresponding to experiments in vitro, the therapeutic effect of KPF was also assessed using heart tissues from mice.

RESULTS

KPF significantly inhibited high glocose (HG) induced expression of inflammatory cytokines and generation of ROS, leading to reduced fibrotic responses and cell apoptosis in vitro. KPF mediated DCM protective effects through inhibiting nuclear factor-κB (NF-κB) nucleus translocation and activating nuclear factor-erythroid 2 p45-related factor-2 (Nrf-2). In STZ-induced type 1 diabetic mouse model, KPF prevented diabetes-induced cardiac fibrosis and apoptosis. These changes were also accompanied by reducing inflammation and oxidative stress in diabetic mice hearts.

CONCLUSION

KPF is a potential therapeutic agent for the treatment of DCM, mechanically linked to inhibition of NF-κB and Nrf-2 activation.

Ethnopharmacology, phytochemistry, and pharmacology of Cornus officinalis Sieb. et Zucc

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis (Cornaceae), known in Chinese as "Shanzhuyu," is a frequently used traditional Chinese medicine. It tastes sour and is astringent and slightly warm in nature. Its fruits have long been used to treat kidney deficiency, high blood pressure, waist and knee pain, dizziness, tinnitus, impotence, spermatorrhea, menorrhagia, and other diseases in China. The main distribution areas are Shanxi and Gansu.

AIM OF THE STUDY

This review focused on the ethnopharmacological uses of the herb. We also focus on the phytochemical, pharmacological, and toxicological studies on C. officinalis. The recent analytical methods developed for the quality control of the herb's constituents are also reviewed. Additionally, future trends and prospects in the study of this herb are proposed.

MATERIALS AND METHODS

Information on C. officinalis was gathered by searching the internet (PubMed, ScienceDirect, Wiley, ACS, CNKI, Scifinder, Web of Science, Google Scholar, and Baidu Scholar) and libraries.

RESULTS

This review compiled the ethnopharmacological uses, including the classic prescriptions and historical applications. Approximately 300 chemical compounds have been isolated and identified from C. officinalis. The major active components of the plant are organic acids and iridoids, among which morroniside and loganin have been extensively investigated. The fruit of the plant has been used in treating many diseases in traditional medicine. Scientific studies indicated the herb's wide range of pharmacological activities, such as hepatic and renal protection, antidiabetes activity, cardioprotection, antioxidation, neuroprotection, antitumor activity, anti-inflammation, analgesic effects, antiaging activity, antiamnesia, antiosteoporosis, and immunoregulation. The analytical methods developed for the quantitative and qualitative determination of various compounds in the herb were further reviewed.

CONCLUSIONS

In this paper, we reviewed various studies conducted on C. officinalis, especially in areas of its ethnopharmacological use, as well as on its phytochemistry, pharmacology, and modern analytical methods used. Some of the herb's ethnomedical indications have been confirmed by the herb's pharmacological effects, such as its hepatic and renal protection and the antidiabetic effects. In particular, the crude extract and its chemical composition have exerted good therapeutic effect in diabetic treatment. C. officinalis entails additional attention on its pharmacological effects and drug development to expand its effective use clinically. Many advanced technologies are used for quality testing, but the detection component is exceedingly scarce for synthetically evaluating the quality of C. officinalis herbs. Thus, further research is necessary to investigate the quality control and toxicology of the plant, to further elucidate its clinical use, and to control herbal quality.

Cornusides A-O, Bioactive Iridoid Glucoside Dimers from the Fruit of Cornus officinalis

Fifteen new and rare iridoid glucoside dimers, cornusides A-O (1-15), and 10 known iridoid glucosides (16-25) were isolated from the fruit of Cornus officinalis. These new chemical structures were established through spectroscopic analysis (UV, IR, HRESIMS, 1D and 2D NMR). Compounds 1-25 were tested for their inhibitory activities by measuring IL-6-induced STAT3 promoter activity in HepG2 cells, and 3, 12, 17, 22, and 23 showed inhibitory effects, with IC₅₀ values of 11.9, 12.2, 14.0, 7.0, and 6.9 μM, respectively.

Synthesis, characterization and evaluation cytotoxic activity of silver nanoparticles synthesized by Chinese herbal Cornus officinalis via environment friendly approach

Cornus officinalis has been widely used as a precious herb and as the tonic food to improve kidney function in China. Its fruits have been used in many traditional Chinese medicine prescriptions to treat kidney diseases, diabetes, cancer and shock. In this study, a new eco-friendly approach for green synthesis of silver nanoparticles (AgNPs) by using the fruits of Cornus officinalis aqueous extract as a reducing and stabilizing agent. The so-synthesized AgNPs showed quasi-spherical in shape with uniform dispersal and an average mean size of 11.7nm. Water soluble biomolecules such as flavonoids and/or anthocyanins from the extract played important roles in the nanoparticles formation. The AgNPs displayed distinctive cytotoxicity activities against human prostate cancer (PC-3) and human liver cancer (HepG2) cell lines. The results provided a low cost, nontoxic and eco-friendly approach for synthesizing metal nanoparticles to explore alternative anticancer agents on the way fighting against cancer in future.

Preparative Separation and Purification of Four Glycosides from Gentianae radix by High-Speed Counter-Current Chromatography and Comparison of Their Anti-NO Production Effects

Secoiridoid and iridoid glycosides are the main active components of Gentianae radix. In this work, one iridoid and three secoiridoid glycosides from Gentianae radix have been purified by high-speed counter-current chromatography in two runs using different solvent systems. Ethyl acetate–n-butanol–water (2:1:3, v/v/v) was the optimum solvent system to purify ca. 4.36 mg of loganic acid, 3.05 mg of swertiamarin, and 35.66 mg of gentiopicroside with 98.1%, 97.2% and 98.6% purities, respectively, while 31.15 mg of trifloroside with 98.9% purity was separated using hexane–ethyl acetate–methanol–water (1:3:1:3, v/v/v/v). The structures of the glycosides were identified by mass spectrometry and NMR. After separation, the anti-nitric oxide production effects of the compounds on lipopolysaccharide-induced BV-2 murine microglial cells were also evaluated. All of the compounds inhibited the production of nitric oxide in lipopolysaccharide-induced BV-2 cells with high cell viabilities in a concentration-dependent manner, which demonstrated that were able to be used as a nitric oxide inhibitor.

Variation of loganin content in Cornus officinalis fruits at different extraction conditions and maturation stages

Efficient preparation of loganin from Cornus officinalis fruits was investigated. First, effect of extraction conditions on loganin yield was measured. The loganin content in C. officinalis extract was greatly affected by ethanol concentration and extraction time whereas extraction temperature exerted relatively little effect. Response surface methodology with Box-Behnken design suggested optimized extraction condition for maximum loganin yield as ethanol concentration, 32.0%; temperature 46.2 °C and extraction time, 46.7 min, which yielded 10.4 μg loganin/mg dried fruit. Next, the effect of maturation stage of C. officinalis fruits on loganin content was investigated. The loganin content in the extract of C. officinalis fruits was decreased as the maturation process. The loganin content in the unripe fruits was 18.0 μg/mg extract whereas reduced to 13.3 μg/mg extract for ripe fruits. Taken together, our present study suggested the importance of extraction condition and maturation stages for efficient preparation of loganin from C. officinalis fruits.

Four new iridoid glucosides containing the furan ring from the fruit of Cornus officinalis

Four new and rare iridoid glucosides, cornusfuroside A-D (1-4), containing the furan ring were identified from water extract of the fruit of Cornus officinalis. These new chemical structures were determined through extensive spectroscopic analysis, including 1D and 2D NMR, IR, HRESIMS, experimental and calculated electronic circular dichroism (ECD). Notably, this study is the first report on the isolation of four iridoid glucoside structures with acetal functions in the sugar moiety. The neuroprotective effects of these compounds were also evaluated in vitro.

Iridoids, Phenolic Compounds and Antioxidant Activity of Edible Honeysuckle Berries (Lonicera caerulea var. kamtschatica Sevast.)

Iridoid and polyphenol profiles of 30 different honeysuckle berry cultivars and genotypes were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ion modes and quantified by HPLC-PDA. The 50 identified compounds included 15 iridoids, 6 anthocyanins, 9 flavonols, 2 flavanonols (dihydroflavonols), 5 flavones, 6 flavan-3-ols, and 7 phenolic acids. 8-epi-Loganic acid, pentosyl-loganic acid, taxifolin 7-O-dihexoside, and taxifolin 7-O-hexoside were identified in honeysuckle berries for the first time. Iridoids and anthocyanins were the major groups of bioactive compounds of honeysuckle constituents. The total content of quantified iridoids and anthocyanins was between 128.42 mg/100 g fresh weight (fw) (‘Dlinnoplodnaya’) and 372 mg/100 g fw (‘Kuvshinovidnaya’) and between 150.04 mg/100 g fw (‘Karina’) and 653.95 mg/100 g fw (‘Amur’), respectively. Among iridoids, loganic acid was the dominant compound, and it represented between 22% and 73% of the total amount of quantified iridoids in honeysuckle berry. A very strong correlation was observed between the antioxidant potential and the quantity of anthocyanins. High content of iridoids in honeysuckle berries can complement antioxidant properties of phenolic compounds.

Iridoid glycoside from Cornus officinalis ameliorated diabetes mellitus-induced testicular damage in male rats: Involvement of suppression of the AGEs/RAGE/p38 MAPK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus officinalis (CO) has been widely used as a traditional Chinese medicine for treating diabetes mellitus (DM) and its complications. Iridoid glycoside from C. officinalis (IGCO) can resist apoptosis, hyperglycemia, oxidation and so on. The aim of this study was to investigate the therapeutic effects of IGCO on DM-induced testicular damage through inhibition of the AGEs/RAGE/p38 MAPK signaling pathway.

MATERIALS AND METHODS

A DM model of male Wistar rats was induced with streptozotocin injection (30mg/kg, i.p.) and high-fat diet. The DM rats were administrated with IGCO at low and high doses (15 and 30mg/kg, p.o.) for 12 weeks. Testicular damage was evaluated by estimating relative testicular weights, testicular pathohistology, sperm count, live sperm rate, endogenous sex hormone level and activity of testicular marker enzymes. Besides, general diabetic symptoms, renal function, oxidative stress parameters and testicular apoptosis marker were also determined. Finally, the mechanism was explored based on the AGEs/RAGE/p38 MAPK pathway.

RESULTS

IGCO effectively mitigated the general symptoms of DM rats including weight loss, polydipsia, polyphagia, polyuria, elevated blood glucose level and low serum insulin level. Nourishing the kidney evidently, IGCO reduced serum creatinine, urea nitrogen and urine protein excretion, and also markedly protected against DM-induced testicular damage by increasing testis/body weight ratio and live sperm rate, improving the histomorphology of testes, upregulating testosterone, LH, FSH and GnRH levels and preventing the decrease of testicular marker enzymes LDH, ACP and γ-GT. Moreover, IGCO showed considerable anti-oxidative and anti-apoptotic effects, which downregulated the increase of ROS and MDA levels, restored SOD and CAT activities, and decreased spermatogenic cell apoptosis and Bax/Bcl-2 ratio. In the end, the increased AGEs, RAGE and p-p38 MAPK protein levels in DM rats were also reversed by IGCO significantly.

CONCLUSIONS

The kidney tonic IGCO well protected DM rats from testicular damage, which may be related to suppression of the AGEs-RAGE-p38 MAPK pathway.

Cornus mas L. (cornelian cherry), an important European and Asian traditional food and medicine: Ethnomedicine, phytochemistry and pharmacology for its commercial utilization in drug industry

ETHNOPHARMACOLOGICAL RELEVANCE

Cornus mas L. (cornelian cherry) fruits have been used for centuries as traditional cuisine and folk medicine in various countries of Europe and Asia. In folk medicines, the fruits and other parts of the plant have been used for prevention and treatment of a wide range of diseases such as diabetes, diarrhea, gastrointestinal disorders, fevers, rheumatic pain, skin and urinary tract infections, kidney and liver diseases, sunstroke, among others. This review provides a systematic and constructive overview of ethnomedicinal uses, chemical constituents and pharmacological activities of this plant as well as future research need for its commercial utilization as nutraceutical food supplement and medicine.

MATERIALS AND METHODS

This review is based on available literature on ethnomedicinal uses, phytochemical, pharmacological, toxicity and clinical studies on Cornus mas L. (cornelian cherry) fruits and other organs that was collected from electronic (SciFinder, PubMed, Science Direct and ACS among others) and library searches of books and journals.

RESULTS

Versatile ethnomedicinal uses of the plant in different European and Asian countries have been reported. Phytochemical investigations on different parts of this plant have resulted in the identification of 101 compounds, among which anthocyanins, flavonoids and iridoids are the predominant groups. The crude extracts of fruits and other parts of the plant and their pure isolates exhibit a broad spectrum of pharmacological activities such as anti-microbial, anti-diabetic, anti-atherosclerotic, cyto-, hepato-, neuro- and renalprotective, antiplatelet and antiglaucomic activities. Anthocyanins, flavonoids, iridoids and vitamin C are the major bioactive constituents of the fruits. Fruits are non-toxic and safe food on acute toxicity studies in rat and human models. Clinical trials in diabetic type2 and hyperlipidemic patients showed significant trends of amelioration in sugar level, insulin secretion in diabetic patients and amelioration of lipid profile, apolipoprotein status and vascular inflammation in hyperlipidemic patients.

CONCLUSION

Based on our review, Cornus mas L. (cornelian cherry) fruits and leaves can be used mainly in the treatment of diabetes, obesity, atherosclerosis, skin diseases, gastrointestinal and rheumatic problems. Some indications from ethnomedicines have been validated by pharmacological activities of the fruits and its extracts/pure isolates. The reported data reveal that the fruits are a potential source for treatment of diabetes, obesity, hyperlipidemia and gastrointestinal disorders. Unfortunately, the pharmacological studies in these areas are still insufficient to substantiate these preventive effects in confirmatory trials on the mass-scale clinical settings. Future studies on mechanisms of action, bioavailability, pharmacokinetics and adverse effects of the extracts and their bioactive constituents as well as their effective doses and long term toxic effects in humans are needed for commercial applications of these extracts/isolates in modern medicines. The available literature showed that most of the activities of the extracts are due to their constituents, anthocyanins, flavonoids and other phenolics, iridoids and vitamins for their antioxidant and other properties.

Iridoids are natural glycation inhibitors

Glycation of amino acid residues in proteins leads to the eventual formation of advanced glycation end products (AGEs). AGE formation significantly influences human health and the aging process. AGE accumulation rates may be slowed by modifications to lifestyle or by pharmacological strategies. But the use of therapeutic drugs is not an appropriate means of controlling AGEs within the general population. However, phytochemical constituents in plant-based foods exhibit anti-glycation activities and may be more appropriate for general consumption. Among these phytochemicals are iridoids. The anti-AGE potential of iridoids has been demonstrated in vitro and in vivo, while also revealing possible mechanisms of action. Inclusion of iridoid food sources in the diet may be a useful component of strategies intended to mitigate AGE accumulation within the body.

Effect of morroniside on glomerular mesangial cells through AGE-RAGE pathway

Diabetes mellitus is an endocrine and metabolic disease characterized by high blood glucose. Diabetic nephropathy (DN) is one of the most typical diabetic complications. Cornus officinalis is a type of traditional Chinese medicine that replenishes the liver and kidney. Morroniside is one of the main characteristic components of C. officinalis. In this study, an in vitro model for simulating DN damage was established by stimulating rat glomerular mesangial cells by the advanced glycation end products. The protective mechanism and effect of morroniside in regulating receptor for advanced glycation end products signaling pathway in DN was investigated to provide experimental evidence for the prevention and treatment of DN.

The Hypoglycemic and Synergistic Effect of Loganin, Morroniside, and Ursolic Acid Isolated from the Fruits of Cornus officinalis

Hypoglycemic activity-guided separation of ethanol extracts from the fruits of Cornus officinalis Sieb. et Zucc (CO) led to the isolation of loganin, morroniside, and ursolic acid. The antidiabetic capacity of CO extracts and related compounds was further investigated in diabetes mellitus mice. The results suggested that both CO extracts and pure compounds could ameliorate diabetes-associated damages and complications. Oral administration of loganin and morroniside decreased fasting blood glucose levels in diabetes mellitus mice. Ursolic acid exhibited the highest reactive oxygen species scavenging activity and α-glucosidase inhibitory activity. Notably, we noticed an interesting synergistic effect between loganin and ursolic acid. Given these favorable hypoglycemic properties, C. officinalis, a food and medicinal plant in China, may be used as a valuable food supplement for the treatment of diabetes mellitus.

Review of Herbal Traditional Chinese Medicine for the Treatment of Diabetic Nephropathy

Diabetic nephropathy (DN) is the most serious chronic complications of diabetes; 20-40% of diabetic patients develop into end stage renal disease (ESRD). However, exact pathogenesis of DN is not fully clear and we have great difficulties in curing DN; poor treatment of DN led to high chances of mortality worldwide. A lot of western medicines such as ACEI and ARB have been demonstrated to protect renal function of DN but are not enough to delay or retard the progression of DN; therefore, exploring exact and feasible drug is current research hotspot in medicine. Traditional Chinese medicine (TCM) has been widely used to treat and control diabetes and its complications such as DN in a lot of scientific researches, which will give insights into the mechanism of DN, but they are not enough to reveal all the details. In this paper, we summarize the applications of herbal TCM preparations, single herbal TCM, and/or monomers from herbal TCM in the treatment of DN in the recent 10 years, depicting the renal protective effects and the corresponding mechanism, through which we shed light on the renal protective roles of TCM in DN with a particular focus on the molecular basis of the effect and provide a beneficial supplement to the drug therapy for DN.

Comparative pharmacokinetics of the main compounds of Shanzhuyu extract after oral administration in normal and chronic kidney disease rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pharmacokinetic studies on traditional Chinese medicine are useful to evaluate and predict the drug efficacy and safety. The renal impairment may affect drug clearance and other pharmacokinetic processes which can increase toxicity and drug to drug interactions or cause ineffective therapy. Pharmacokinetic studies in pathological status rats might be meaningful for revealing the action mechanism and improving clinical medication of the herb medicine.

MATERIALS AND METHODS

A highly sensitive and rapid ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method with multiple-reaction monitoring (MRM) mode was developed and validated for simultaneous quantitation of morroniside and loganin in normal and doxorubicin-induced chronic kidney disease (CKD) rat plasma after oral administration of Shanzhuyu (fruit of Cornus officinalis) extract.

RESULTS

Both calibration curves gave satisfactory linearity (r>0.99) at linear range of 1.96-1962.5ngmL(-1) for morroniside, 1.53-1531.25ngmL(-1) for loganin. The precision and accuracy of the in vivo study were assessed by intra-day and inter-day assays. The percentages of relative standard deviation (RSD) were all within 9.58% and the accuracy (RE) was in the -6.02% to 8.11% range. The extraction recoveries of morroniside, loganin and internal standard (IS) were all >67.62% and the matrix effects ranged from 95.07% to 102.75%.

CONCLUSIONS

The pharmacokinetic behavior of morroniside and loganin in normal and CKD rat plasma was determined in this paper. The significant different pharmacokinetic parameters might partly result from the changes of P-glycoprotein and metabolic enzymes in the pathological state. The pharmacokinetic research in the pathological state might provide more useful information to guide the clinical usage of the herb medicine.

Application of Cornelian Cherry Iridoid-Polyphenolic Fraction and Loganic Acid to Reduce Intraocular Pressure

One of the most common diseases of old age in modern societies is glaucoma. It is strongly connected with increased intraocular pressure (IOP) and could permanently damage vision in the affected eye. As there are only a limited number of chemical compounds that can decrease IOP as well as blood flow in eye vessels, the up-to-date investigation of new molecules is important. The chemical composition of the dried Cornelian cherry (Cornus mas L.) polar, iridoid-polyphenol-rich fraction was investigated. Loganic acid (50%) and pelargonidin-3-galactoside (7%) were found as the main components. Among the other constituents, iridoid compound cornuside and the anthocyans cyanidin 3-O-galactoside, cyanidin 3-O-robinobioside, and pelargonidin 3-O-robinobioside were quantified in the fraction. In an animal model (New Zealand rabbits), the influence of loganic acid and the polyphenolic fraction isolated from Cornelian cherry fruit was investigated. We found a strong IOP-hypotensive effect for a 0.7% solution of loganic acid, which could be compared with the widely ophthalmologically used timolol. About a 25% decrease in IOP was observed within the first 3 hours of use.