Induction of nerve growth factor by butanol fraction of Liriope platyphylla in C6 and primary astrocyte cells

A novel exopolysaccharide-producing bacterium, Pseudescherichia liriopis sp. nov. isolated from Liriope platyphylla, enhances the growth of Daucus carota subsp. sativus under drought and salinity stress

Biological and abiotic stresses in plant growth are associated with reduced crop yields. Therefore, improving plant stress resistance can be a crucial strategy to improve crop production. To overcome these problems, plant growth-promoting bacteria are emphasized as one of the alternative tools for sustainable agriculture. This study found a novel strain (L3T) of a plant growth-promoting bacterium in fermented Liriope platyphylla fruit. Strain L3T showed the ability to promote plant growth. The L3T strain promoted plant growth of D. carota subsp. sativus, increasing the length (increase rate compared to the control group, 36.98%), diameter (47.06%), and weight of carrots (81.5%), ultimately increasing the edible area. In addition, we confirmed that plant growth was improved even in situations that inhibited plant growth, such as salinity and drought stress. Strain L3T performed indole production, siderophore production, phosphate solubilization, and nitrogen fixation, all characteristics of a strain that promotes plant growth. Genome analysis revealed genes involved in the growth promotion effects of strain L3T. Additionally, the properties of exopolysaccharides were identified and characterized using FTIR, TGA, and UHPLC. Our results demonstrated that L3 isolated from fermented L. platyphylla fruit can be used to simultaneously alleviate drought and NaCl stress.

Ethanol Extract of Liriope platyphylla Root Attenuates Non-Alcoholic Fatty Liver Disease in High-Fat Diet-Induced Obese Mice via Regulation of Lipogenesis and Lipid Uptake

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disorder that causes excess lipid accumulation in the liver and is the leading cause of end-stage liver disease. Liriope platyphylla is a medicinal herb that has long been used to treat cough, obesity, and diabetes. However, the effect of Liriope platyphylla on NAFLD has not been studied. The aim of this study was to investigate the effect of Liriope platyphylla root ethanolic extract (LPE) on hepatic lipid accumulation in high-fat diet (HFD)-induced obese mice. Six-week-old C57BL/6 male mice were fed a HFD for 8 weeks and then treated with LPE (100 or 250 mg/kg/day) by oral gavage for another 8 weeks. Body weight gain and liver weight were significantly lower in the 250 mg/kg LPE-treated HFD group than in the vehicle-treated HFD group. Histological analysis of liver sections demonstrated that LPE treatment reduced lipid accumulation compared to the vehicle treatment. The serum total cholesterol, AST, and ALT levels significantly decreased in the LPE-treated HFD group compared to those in the vehicle-treated HFD group. The LPE significantly decreases the protein expression levels of SREBP1, ACC, p-ACC, FAS, and SCD1, which are involved in lipogenesis, and PPARγ, CD36/FAT, and FATP5, which are involved in fatty acid uptake, both in vivo and in vitro. Thus, LPE may attenuate HFD-induced NAFLD by decreasing lipid accumulation by inhibiting lipogenesis and fatty acid uptake.

Natural Products for Neurodegeneration: Regulating Neurotrophic Signals

Neurodegenerative disorders (NDs) are heterogeneous groups of ailments typically characterized by progressive damage of the nervous system. Several drugs are used to treat NDs but they have only symptomatic benefits with various side effects. Numerous researches have been performed to prove the advantages of phytochemicals for the treatment of NDs. Furthermore, phytochemicals such as polyphenols might play a pivotal role in rescue from neurodegeneration due to their various effects as anti-inflammatory, antioxidative, and antiamyloidogenic agents by controlling apoptotic factors, neurotrophic factors (NTFs), free radical scavenging system, and mitochondrial stress. On the other hand, neurotrophins (NTs) including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT4/5, and NT3 might have a crucial neuroprotective role, and their diminution triggers the development of the NDs. Polyphenols can interfere directly with intracellular signaling molecules to alter brain activity. Several natural products also improve the biosynthesis of endogenous genes encoding antiapoptotic Bcl-2 as well as NTFs such as glial cell and brain-derived NTFs. Various epidemiological studies have demonstrated that the initiation of these genes could play an essential role in the neuroprotective function of dietary compounds. Hence, targeting NTs might represent a promising approach for the management of NDs. In this review, we focus on the natural product-mediated neurotrophic signal-modulating cascades, which are involved in the neuroprotective effects.

Topical Application of Liriope platyphylla Extract Attenuates Dry Eye Syndrome Induced by Particulate Matter

Particulate matter (PM) is a type of air pollutant that poses a risk to human health. In the ocular system, PM causes or aggravates dry eye syndrome (DES) by damaging the corneal and conjunctival epithelia. Liriope platyphylla has been used traditionally as an expectorant, antitussive agent, and tonic in Korea. However, the effects of Liriope platyphylla extract (LPE) on PM-induced ocular damage have not been elucidated. In this study, we evaluated the in vivo protective effect of LPE against PM-induced DES in rats. Topical administration of LPE attenuated the PM-induced decrease in tear volume and reduced corneal epithelial irregularity and damage. LPE also protected against PM-induced disruption of the corneal mucin-4 layer and reduction in the conjunctival goblet cell density. These findings suggest that LPE has protective effects against PM-induced DES.

Metabolic Analysis of Four Cultivars of Liriope platyphylla

Liriope platyphylla (Liliaceae), a medical plant distributed mainly in China, Taiwan, and Korea, has been used traditionally for the treatment of cough, sputum, asthma, and neurodegenerative diseases. The present study involved the metabolic profiling of this plant and reports spicatoside A accumulation in four different varieties of L. platyphylla (Cheongyangjaerae, Seongsoo, Cheongsim, and Liriope Tuber No. 1) using HPLC and gas chromatography time-of-flight mass spectrometry (GC⁻TOFMS). A total of 47 metabolites were detected in the different cultivars using GC⁻TOFMS-based metabolic profiling. The resulting data were subjected to principal component analysis (PCA) for determining the whole experimental variation, and the different cultivars were separated by score plots. Furthermore, hierarchical clustering, Pearson's correlation, and partial least-squares discriminant analyses (PLS-DA) were subsequently performed to determine significant differences in the various metabolites of the cultivars. The HPLC data revealed that the presence of spicatoside A was detected in all four cultivars, with the amount of spicatoside A varying among them. Among the cultivars, Liriope Tuber No. 1 contained the highest amount of spicatoside A (1.83 ± 0.13 mg/g dry weight), followed by Cheongyangjaerae (1.25 ± 0.01 mg/g dry weight), Cheongsim (1.09 ± 0.04 mg/g dry weight), and Seongsoo (1.01 ± 0.02 mg/g dry weight). The identification of spicatoside A was confirmed by comparing the retention time of the sample with the retention time of the standard. Moreover, the Cheongsim cultivar contained higher levels of phenolic compounds-including vanillic acid, quinic acid, gallic acid, chlorogenic acid, caffeic acid, and benzoic acid-than those of the other two cultivars. On the other hand, the levels of amino acids were higher in the Seongsoo cultivar. Therefore, this study may help breeders produce new varieties with improved nutraceutical and nutritional qualities.

The genus Liriope: Phytochemistry and pharmacology

Liriope (Liliaceae) species have been used as folk medicines in Asian countries since ancient times. From Liriope plants (8 species), a total of 132 compounds (except polysaccharides) have been isolated and identified, including steroidal saponins, flavonoids, phenols, and eudesmane sesquiterpenoids. The crude extracts or monomeric compounds from this genus have been shown to exhibit anti-tumor, anti-diabetic, anti-inflammatory, and neuroprotective activities. The present review summarizes the results on phytochemical and biological studies on Liriope plants. The chemotaxonomy of this genus is also discussed.

Anti-stress and neuronal cell differentiation induction effects of Rosmarinus officinalis L. essential oil

Background

Mood disorder accounts for 13 % of global disease burden. And while therapeutic agents are available, usually orally administered, most have unwanted side effects, and thus making the inhalation of essential oils (EOs) an attractive alternative therapy. Rosmarinus officinalis EO (ROEO), Mediterranean ROEO reported to improve cognition, mood, and memory, the effect on stress of which has not yet been determined. Here, the anti-stress effect of ROEO on stress was evaluated in vivo and in vitro.

Methods

Six-week-old male ICR mice were made to inhale ROEO and subjected to tail suspension test (TST). To determine the neuronal differentiation effect of ROEO in vitro, induction of ROEO-treated PC12 cells differentiation was observed. Intracellular acetylcholine and choline, as well as the Gap43 gene expression levels were also determined.

Results

Inhalation of ROEO significantly decreased the immobility time of ICR mice and serum corticosterone level, accompanied by increased brain dopamine level. Determination of the underlying mechanism in vitro revealed a PC12 differentiation-induction effect through the modulation of intracellular acetylcholine, choline, and Gap43 gene expression levels. ROEO activates the stress response system through the NGF pathway and the hypothalamus-pituitary-adrenal axis, promoting dopamine production and secretion. The effect of ROEO may be attributed to its bioactive components, specifically to α-pinene, one of its major compounds that has anxiolytic property.

Conclusions

The results of this study suggest that ROEO inhalation has therapeutic potential against stress-related psychiatric disorders.

Anti-Inflammatory Effects of Liriope platyphylla in LPS-Stimulated Macrophages and Endotoxemic Mice

In the present study, the anti-inflammatory and antisepticemic activities of a water extract of Liriope platyphylla (LP) were investigated. We first estimated the scavenging activity of DPPH and the hydroxyl radical and total phenolic contents of LP. Results indicated that LP, a rich source of phenolic compounds, showed a remarkable radical scavenging capacity. A MTT assay showed that LP treatment did not affect the toxicity against the RAW 264.7 macrophage cells, up to the concentration of 500[Formula: see text][Formula: see text]g/mL. Treatment of LP significantly attenuated the production of inflammatory mediators, such as nitric oxide (NO), interleukin-6 (IL-6), tumor-necrosis factor (TNF)-[Formula: see text] and prostaglandin (PG)E2 in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages cells. Moreover, LP contributed to the down-regulation of inducible NO synthase (iNOS) and TNF-[Formula: see text] mRNA expression, as well as cyclooxygenase-2 (COX-2) protein expression. A western blotting assay further showed that LP inhibited activation of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-[Formula: see text]B. In an animal experiment using an LPS-induced septicemia model in C57BL/6 mice, oral administration of LP (40[Formula: see text]mg/kg body weight) markedly reduced the level of TNF-[Formula: see text] and IL-6 in serum and protected against LPS-induced lethal shock in mice. Taken together, the results of treatments of LP on inhibited LPS-induced inflammatory responses in both in vitro and in vivo models and indicate it may be a promising neutraceutical or medicinal agent to prevent or cure inflammation-related disease.

Pharmacological Activities and Applications of Spicatoside A

Liriopogons (Liriope and Opiopogon) species are used as a main medicinal ingredient in several Asian countries. The Liriopes Radix (tuber, root of Liriope platyphylla) has to be a promising candidate due to their source of phytochemicals. Steroidal saponins and their glycosides, phenolic compounds, secondary metabolites are considered of active constituents in Liriopes Radix. Spicatoside A, a steroidal saponin, could be more efficacious drug candidate in future. In this review, we summarized the available knowledge on phytochemical and pharmacological activities for spicatoside A. It significantly suppressed the level of NF-κB, NO, iNOS, Cox-2, IL-1β, IL-6 and MAPKs in LPS-stimulated inflammation. The production of MUC5AC mucin was increased. MMP-13 expression was down-regulated in IL-1β-treated cells and reduced glycosaminoglycan release from IL-1α-treated cells. The neurite outgrowth activity, PI3K, Akt, ERK1/2, TrkA and CREB phosphorylation and neurotropic factors such as NGF and BDNF were upregulated with increased latency time. It also showed cell growth inhibitory activity on various carcinoma cells. From this, spicatoside A exerts anti-inflammation, anti-asthma, anti-osteoclastogenesis, neurite outgrowth, memory consolidation and anticancer activities. Further studies are needed on spicatoside A in order to understand mechanisms of action to treat various human diseases.

Antitumor Activity of Spicatoside A by Modulation of Autophagy and Apoptosis in Human Colorectal Cancer Cells

The antitumor activity of spicatoside A (1), a steroidal saponin isolated from the tuber of Liriope platyphylla, and its underlying mechanisms were investigated in HCT116 human colorectal cancer cells. Compound 1 induced autophagy and apoptotic cell death and inhibited tumor growth in a nude mouse xenograft model implanted with HCT116 cells. Treatment with 1 for 24 h enhanced the formation of acidic vesicular organelles in the cytoplasm, indicating the induction of the onset of autophagy. This event was associated with the regulation of autophagic markers including microtubule-associated protein 1 light chain 3 (LC3)-II, p62, beclin 1, lysosomal-associated membrane protein 1 (LAMP 1), and cathepsin D by inhibiting the PI3K/Akt/mTOR signaling pathway, regulating mitogen-activated protein kinase (MAPK) signaling, and increasing p53 levels. However, a prolonged exposure to 1 resulted in apoptosis characterized by the accumulation of a sub-G1 cell population and an annexin V/propidium iodide (PI)-positive cell population. Apoptosis induced by 1 was associated with the regulation of apoptotic proteins including Bcl-2, Bax, and Bid, the release of cytochrome c into the cytosol, and the accumulation of cleaved poly-ADP-ribose polymerase (PARP). Further study revealed that cleavage of beclin 1 by caspases plays a critical role in the 1-mediated switch from autophagy to apoptosis. Taken together, these findings highlight the significance of 1 in the modulation of crosstalk between autophagy and apoptosis, as well as the potential use of 1 as a novel candidate in the treatment of human colorectal cancer cells.

Phytochemicals that regulate neurodegenerative disease by targeting neurotrophins: a comprehensive review

Alzheimer's disease (AD), characterized by progressive dementia and deterioration of cognitive function, is an unsolved social and medical problem. Age, nutrition, and toxins are the most common causes of AD. However, currently no credible treatment is available for AD. Traditional herbs and phytochemicals may delay its onset and slow its progression and also allow recovery by targeting multiple pathological causes by antioxidative, anti-inflammatory, and antiamyloidogenic properties. They also regulate mitochondrial stress, apoptotic factors, free radical scavenging system, and neurotrophic factors. Neurotrophins such as BDNF, NGF, NT3, and NT4/5 play a vital role in neuronal and nonneuronal responses to AD. Neurotrophins depletion accelerates the progression of AD and therefore, replacing such neurotrophins may be a potential treatment for neurodegenerative disease. Here, we review the phytochemicals that mediate the signaling pathways involved in neuroprotection specifically neurotrophin-mediated activation of Trk receptors and members of p75(NTR) superfamily. We focus on representative phenolic derivatives, iridoid glycosides, terpenoids, alkaloids, and steroidal saponins as regulators of neurotrophin-mediated neuroprotection. Although these phytochemicals have attracted attention owing to their in vitro neurotrophin potentiating activity, their in vivo and clinical efficacy trials has yet to be established. Therefore, further research is necessary to prove the neuroprotective effects in preclinical models and in humans.

Phytochemicals and Estrogen-Receptor Agonists from the Aerial Parts of Liriope platyphylla

One new benzofuran, (2R)-(2',4'-dihydroxybenzyl)-6,7-methylenedioxy-2,3-dihydrobenzofuran (1), one new phenylisocoumarin, 3-(2'-hydroxyphenyl)-6,8-dihydroxy-7-methoxy-isocoumarin (2), and one new benzofuroisocoumarin, platyphyllarin C (3), were isolated from the ethanolic extract of Liriope platyphylla aerial parts, along with seventeen known compounds. The structures of the isolates were established by spectroscopic analysis and comparison with the literature data. The results indicated that structures 1-3 are uncommon in Nature. Benzofuroisocoumarin 4, flavonoids 9, 10, and 13-15, and homoisoflavonoids 19 and 20 exhibited significant binding activity to estrogen-receptor α and/or β as demonstrated by the SEAP reporter assay system in an MCF-7 cell-line.

Anti-viral effect of a compound isolated from Liriope platyphylla against hepatitis B virus in vitro

The compound LPRP-Et-97543 was isolated from Liriope platyphylla roots and was observed to have potential anti-viral effects in HepG2.2.15 cells against hepatitis B virus (HBV). The antiviral mode was further clarified, and the HBV-transfected Huh7 cells were used as the platform. During viral gene expression, LPRP-Et-97543 treatment had apparent effects on the viral precore/pregenomic and S/preS RNA. Promoter activity analysis demonstrated that LPRP-Et-97543 significantly reduced Core, S, and preS but not X promoter activities. Further examination showed that putative signaling pathways were involved in this inhibitory effect, indicating that NF-κB may serve a putative mediator of HBV gene regulation with LPRP-Et-97543. In addition, the nuclear expression of p65/p50 NF-κB member proteins was attenuated with LPRP-Et-97543 and augmented cytoplasmic IκBα protein levels but without affecting the expression of these proteins in HBV non-transfected cells during treatment. Moreover, LPRP-Et-97543 reduced the binding activity of NF-κB protein to CS1 element of HBV surface gene in a gel retardation analysis and inhibited CS1 containing promoter activity in HBV expressed cells. However, HBV transfection significantly enhances CS1 containing promoter activity without compound treatment in cells. Finally, transfection of the p65 expression plasmid significantly reversed the inhibitory effect of LPRP-Et-97543 on the replicated HBV DNA level in HBV positive cells. In conclusion, this study suggests that the mechanism of HBV inhibition by LPRP-Et-97543 may involve the feedback regulation of viral gene expression and viral DNA replication by HBV viral proteins, which interferes with the NF-κB signaling pathway.

The effects of Gamijinhae-tang on elastase/lipopolysaccharide-induced lung inflammation in an animal model of acute lung injury

Background

Gamijinhae-tang (GJHT) has long been used in Korea to treat respiratory diseases. The therapeutic effect of GJHT is likely associated with its anti-inflammatory activity. However, the precise mechanisms underlying its effects are unknown. This study was conducted to evaluate the protective effects of GJHT in a porcine pancreatic elastase (PPE) and lipopolysaccharide(LPS) induced animal model of acute lung injury (ALI).

Methods

In this study, mice were intranasally exposed to PPE and LPS for 4 weeks to induce chronic obstructive pulmonary disease (COPD)-like lung inflammation. Two hours prior to PPE and LPS administration, the treatment group was administered GJHT extracts via an oral injection. The numbers of neutrophils, lymphocytes, macrophages and total cells in the bronchoalveolar lavage (BAL) fluid were counted, and pro-inflammatory cytokines were also measured. For histologic analysis, hematoxylin and eosin (H&E) stains and periodic acid-Schiff (PAS) stains were evaluated.

Results

After inducing ALI by treating mice with PPE and LPS for 4 weeks, the numbers of neutrophils, lymphocytes and total cells were significantly lower in the GJHT group than in the ALI group. In addition, the IL-1β and IL-6 levels were significantly decreased in the GJHT group. The histological results also demonstrated the attenuation effect of GJHT on PPE- and LPS-induced lung inflammation.

Conclusions

The results of this study indicate that GJHT has significantly reduces PPE- and LPS-induced lung inflammation. The remarkable protective effects of GJHT suggest its therapeutic potential in COPD treatment.

Red Liriope platyphylla stimulated the insulin secretion through the regulation of calcium concentration in rat insulinoma cells and animal models

The aim of this study was to investigate the effects of Red L. platyphylla (RLP) on calcium and glucose levels during insulin secretion. To achieve this, alteration of insulin and calcium concentrations was measured in rat insulinoma-1 (INS-1) cells and animal models in response to RLP treatment. In INS-1 cells, maximum secretion of insulin was detected upon treatment with 200 µg/mL of RLP for 20 min. Nifedipine, an L-type calcium channel blocker, effectively inhibited insulin secretion from INS-1 cells. Regarding calcium levels, the maximum concentration of intracellular calcium in INS-1 cells was obtained by treatment with 100 µg/mL of RLP, whereas this level was reduced under conditions of 200 µg/mL of RLP. Further, RLP-treated INS-1 cells showed a higher level of intracellular calcium than that of L. platyphylla (LP), Korea White Ginseng (KWG), or Korea Red Ginseng (KRG)-treated cells. This RLP-induced increase in intracellular calcium was abrogated but not completely abolished upon treatment with 40 µM nifedipine in a dose-dependent manner. Furthermore, the insulin level was dramatically elevated upon co-treatment with high concentrations of glucose and RLP, whereas it was maintained at a low level in response to glucose and RLP co-treatment at low concentrations. In an animal experiment, the serum concentration of calcium increased or decreased upon RLP treatment according to glucose level compared to vehicle treatment. Therefore, these results suggest that insulin secretion induced by RLP treatment may be tightly correlated with calcium regulation, which suggests RLP is an excellent candidate for diabetes treatment.

In vitro and in vivo study of effects of fermented soybean product (chungkookjang) on NGF secretion ability and NGF receptor signaling pathway

In order to investigate the effects of a fermented soybean product (Chungkookjang, CKJ) on nerve growth factor (NGF) metabolism, NGF secretion ability and its related signaling pathway were analyzed in B35 neuronal cells and the Tg2576 mouse model of Alzheimer's disease (AD). In B35 cells, the concentration of NGF significantly increased upon treatment with Taegwang (TG)-CKJ and Shinhwa (SH)-CKJ extracts compared with vehicle. Further, a significant increase in PC12 cell length as well as the phsophorylation levels of TrkA and Akt, which are members of a high affinity NGF receptor signaling pathway, were observed after treatment with TG-CKJ and SH-CKJ conditional medium (CM). On the other hand, there was no difference in activation of the NGF receptor p75^NTR signaling pathway between vehicle and all CKJ treated groups. In Tg2576 mice showing early stage of AD, the concentrations of NGF in the serum and brain were reduced compared with those in Non-Tg mice. Treatment of Tg2576 mice with SH-CKJ, which contains high concentrations of total flavonoids and phenolic compounds, for 8 weeks dramatically recovered the NGF level to that of Non-Tg mice. Furthermore, the low phosphorylation levels of TrkA and Erk in the NGF receptor TrkA signaling pathway were rapidly recovered to those of Non-Tg mice after SH-CKJ treatment in vehicle treated Tg2576 mice, whereas the phosphorylation level of Akt was maintained at a constant level. These results suggest that CKJ may stimulate NGF secretion ability as well as the NGF receptor TrkA signaling pathway in PC12 cells and Tg2576 mice.

Toxicity of red Liriope platyphylla manufactured by steaming process on liver and kidney organs of ICR mice

Red Liriope platyphylla (RLP) produced by steaming process has been reported to enhance the secretion of insulin and nerve growth factor (NGF). However, there has been no report on the toxicity of RLP in the specific organs of mice. To investigate the toxic effect of RLP, we tried to observe a significant alteration on body weight, food/water intake, organ weight, liver pathology and kidney pathology in female ICR mice received 12.5, 25.0 and 50.0 mg/kg body weight/day of RLP via gavage for 10 days. Out of seven organs including brain, heart, lung, liver, kidney, spleen and ovary, two organs (heart and lung) showed significantly decreased weights in the medium dosage RLP-treated group, whereas weights of other organs were maintained at constant levels in all dosage groups. In the liver toxicity analysis, no significant increase of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate amino-transferase (AST) were detected in any RLP-treated group compared to vehicle-treated group. The specific pathological changes induced by most of toxic compounds were not observed in the liver in microscopic examination. Furthermore, in the kidney toxicological analysis, a significant enhancement of the blood urea nitrogen (BUN) concentration was detected in the high dosage RLP-treated group compared to the vehicle-treated group. However, the serum creatinine (CA) concentration on the serum biochemistry as well as the pathological changes in microscopic examination were not significantly different between the vehicle- and RLP-treated groups. Therefore, these results suggest that RLP does not induce any specific toxicity in liver or kidney tissues of mice, although the BUN level slightly increased in 50.0 mg/kg of RLP-treated group.

Immunomodulatory effects of Liriope platyphylla water extract on lipopolysaccharide-activated mouse macrophage

The tuber of Liriope platyphylla Wang et Tang (Liliaceae), also known as Liriopis tuber, is famous in Oriental medicine owing to its tonic, antitussive, expectorant and anti-asthmatic properties. In the present study, the effects of Liriopis tuber water extract (LP) on proinflammatory mediators secreted from lipopolysaccharide (LPS)-induced cultured RAW 264.7 mouse macrophages were investigated. Nitric oxide (NO), prostaglandin E2 (PGE2) and intracellular calcium release were measured after 24 h incubation. Various cytokines and nuclear transcription factors (NF-κB and CREB) of LPS-induced RAW 264.7 were measured by a multiplex bead array assay based on xMAP technology. LP (up to 200 μg/mL) significantly decreased levels of nitric oxide (NO), interleukin (IL)-6, IL-10, IL-12p40, interferon-inducible protein-10, keratinocyte-derived chemokine, monocyte chemotactic protein-1, vascular endothelial growth factor, granulocyte macrophage-colony stimulating factor, platelet derived growth factor, PGE2, intracellular calcium, NF-κB and CREB in LPS-induced RAW 264.7 cells (p < 0.05). The results suggest that LP has immunomodulatory activity to reduce excessive immune reactions during the activation of macrophages by LPS. Further studies are needed to verify the precise mechanism regulating immunomodulatory activities of LP.

Effects of Red Liriope platyphylla on NGF secretion ability, NGF receptor signaling pathway and γ-secretase components in NSE/hAPPsw transgenic mice expressing Alzheimer's Disease

Liriope platyphylla (LP) has long been regarded as a curative herb for the treatment of diabetes, asthma, and neurodegenerative disorders. To examine the therapeutic effects of Red LP (RLP) manufactured by steaming process on neurodegenerative disorders, significant alteration of the key factors influencing Alzheimer's Disease (AD) was detected in NSE/hAPPsw transgenic (Tg) mice after RLP treatment. The concentration of nerve growth factor (NGF) in serum increased in RLP-treated NSE/hAPPsw Tg mice compared with vehicle-treated Tg mice. However, downstream effectors of the NGF receptor signaling pathway, including TrkA and p75^NTR proteins, were suppressed in RLP-treated NSE/hAPPsw Tg mice. Especially, Tg mice showed decreased levels of TrkA, p75^NTR, and RhoA expression. Production of Aβ-42 peptides was lower in RLP-treated NSE/hAPPsw Tg mice than in vehicle-treated Tg mice. Further, analysis of γ-secretase components showed that Aβ-42 peptide expression was downregulated. Of the four components, the expression of APH-1 and Nicastrin (NCT) decreased in RLP-treated NSE/hAPPsw Tg mice, whereas expression of PS-2 and Pen-2 was maintained or increased within the same group. Overall, these results suggest that RLP can help relieve neurodegenerative diseases, especially AD, through upregulation of NGF secretion ability, activation of NGF signaling pathway, downregulation of Aβ-42 peptide deposition, and alteration of γ-secretase components.

Aqueous extract of Liriope platyphylla, a traditional Chinese medicine, significantly inhibits abdominal fat accumulation and improves glucose regulation in OLETF type II diabetes model rats

Liriope platyphylla is a medical herb that has long been used in Korea and China to treat cough, sputum, neurodegenerative disorders, obesity, and diabetes. The aims of this study were to determine the antidiabetic and antiobesity effects of aqueous extract of L. platyphylla (AEtLP) through glucose and lipid regulation in both pre-diabetes and obesity stage of type II diabetes model. Two concentrations of AEtLP were orally administrated to OLETF (Otsuka Long-Evans Tokushima Fatty) rats once a day for 2 weeks, after which changes in glucose metabolism and fat accumulation were measured. Abdominal fat mass dramatically decreased in AEtLP-treated OLETF rats, whereas glucose concentration slightly decreased in all AEtLP-treated rats. However, compared to vehicle-treated OLETF rats, only AEtLP10 (10% concentration)-treated OLETF rats displayed significant induction of insulin production, whereas AEtLP5 (5% concentration)-treated OLETF rats showed a lower level of insulin. Although serum adiponectin level increased in only AEtLP5-treated rats, significant alteration of lipid concentration was detected in AEtLP5-treated OLETF rats. Expression of Glut-1 decreased in all AEtLP-treated rats, whereas Akt phosphorylation increased only in AEtLP10-treated OLETF rats. Furthermore, the pattern of Glut-3 expression was very similar with that of Glut-1 expression, which roughly corresponded with the phosphorylation of c-Jun N-teminal kinase (JNK) and p38 in the mitogen-activated protein kinase pathway. Therefore, these findings suggest that AEtLP should be considered as a therapeutic candidate during pre-diabetes and obesity stage capable of inducing insulin secretion from pancreatic β-cells, glucose uptake in liver cells, as well as a decrease in fat and lipid accumulation.

Differential effects of the steaming time and frequency for manufactured red Liriope platyphylla on nerve growth factor secretion ability, nerve growth factor receptor signaling pathway and regulation of calcium concentration

The herb Liriope platyphylla (LP) has been considered to have curative properties for diabetes, asthma and neurodegenerative disorders. To examine the effects of steaming time and frequency of manufactured red LP (RLP) on the nerve growth factor (NGF) secretion ability and NGF receptor signaling pathway, the NGF concentration, cell differentiation, NGF signaling pathway and calcium concentration were analyzed in neuronal cells treated with several types of LPs manufactured under different conditions. The maximum NGF secretion was observed in B35 cells treated with 50 µg/ml LP extract steamed for 9 h (9-SLP) and with two repeated steps (3 h steaming and 24 h air-dried) carried out 7 times (7-SALP). No significant changes in viability were detected in any of the cells treated with the various LPs, with the exception of 0-SLP and 0-SALP. In addition, PC12 cell differentiation was induced by treatment with the NGF-containing conditional medium (CM) collected from the RLP-treated cells. The levels of TrkA and extracellular signal-regulated kinase (ERK) phosphorylation in the high affinity NGF receptor signaling pathway were significantly higher in the cells treated with 3-SLP or 1-SALP/3-SALP CM compared with those treated with the vehicle CM. In the low affinity NGF receptor pathway, the expression levels of most components were higher in the 9-, 15- and 24-SALP CM-treated cells compared with the vehicle CM-treated cells. However, this level was significantly altered in cells treated with 3-SALP CM. Furthermore, an examination of the RLP function on calcium regulation revealed that only the LP- or RLP-treated cells exhibited changes in intracellular and extracellular calcium levels. RLP induced a significant decrease in the intracellular calcium levels and an increase in the extracellular calcium levels. These results suggest the possibility that steaming-processed LP may aid in the relief of neurodegenerative diseases through the NGF secretion ability and NGF signaling pathway.

Diosgenin from Dioscorea nipponica ameliorates diabetic neuropathy by inducing nerve growth factor

Diabetic neuropathy is characterized by axonal degeneration, demyelination, and atrophy in association with failed axonal regeneration, remyelination, and synaptogenesis. Recent reports suggest that reduced levels of nerve growth factor (NGF) may play a significant role in the pathogenesis of diabetic polyneuropathy. In this study, we investigated the regulation of NGF by steroid diosgenin (DG) in a diabetic neuropathy rodent model. We found that DG, the primary spirostane-type steroid in several Dioscorea species, increased NGF levels in the sciatic nerve of diabetic rats. Additionally, DG increased neurite outgrowth in PC12 cells and enhanced nerve conduction velocities in the diabetic neuropathy mouse model. DG-treated diabetic mice showed reduced disarrangement of the myelin sheath and increased area of myelinated axons by electron microscope studies and exhibited improvement in the damaged axons. Our data further suggest that DG increased the nerve conduction velocity through induction of NGF. Thus, our findings indicate that DG, a major sapogenin obtained from Dioscorea nipponica, reverses functional and ultrastructural changes and induces neural regeneration in a diabetic neuropathy model.

Neurotrophic activity of DA-9801, a mixture extract of Dioscorea japonica Thunb. and Dioscorea nipponica Makino, in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Dioscorea japonica Thunb. has been traditionally used to treat polyuria and diabetes in Korea.

AIM OF THE STUDY

We previously report the effects of Dioscorea japonica Thunb. extract on glucose control, NGF induction, and neuroprotection in a rodent diabetic model. Since the most potent fraction, DA-9801, was identified from a mixture of Dioscorea japonica Thunb. (DJ) and Dioscorea nipponica Makino (DN) following bioactivity-guided fractionation, here, we investigated the potential mechanism of the extract activity against diabetic peripheral neuropathy (DPN).

MATERIALS AND METHODS

A 1:3 mixture of DJ and DN was extracted with ethanol (DA-9801) and further fractionated into an ethylacetate-soluble fraction (DA-9801E). Effects of these extracts on neurite outgrowth were measured in PC-12 cells and DRG neurons. Effects on cell viability and TrkA phosphorylation were evaluated in PC-12 cells. NGF induction effect was determined in primary Schwann cells as well as IMS32 cells (immortalized Schwann cells).

RESULTS

No cytotoxicity was observed in PC-12 cells at the concentration below 500 μg/ml of either DA-9801 or DA-9801E. DA-9801 and DA-9801E at 100 μg/ml and 10 μg/ml, respectively, showed a significant effect on neurite outgrowth in PC-12 cells and DRG neurons in the presence of or absence a low concentration of NGF (2 ng/ml). The Trk-A phosphorylation effect of DA9801 was confirmed in PC-12 cells. An NGF induction effect of these extracts was not detected in either IMS-32 cells, or primary Schwann cells.

CONCLUSIONS

The NGF agonistic activity of DA-9801 and DA-9801E was demonstrated, which may contribute to their neuroprotective effect against DPN. Studies of the detailed mechanism of these extracts as well as identification of the active components are warranted for the development of an anti-DPN drug from DJ and DN.

Effects of Steaming Time and Frequency for Manufactured Red Liriope platyphylla on the Insulin Secretion Ability and Insulin Receptor Signaling Pathway

In oriental medicine, Liriope platyphylla (LP) has long been regarded as a curative herb useful for the treatment of diabetes, asthma, and neurodegenerative disorders. The principal objective of this study was to assess the effects of steaming time and frequency for manufactured Red LP (RLP) on insulin secretion ability and insulin receptor signaling pathway. To achieve our goal, several types of LPs manufactured under different conditions were applied to INS cells and streptozotocin (STZ)-induced diabetic ICR mice, after which alterations in insulin concentrations were detected in the culture supernatants and sera. The optimal concentration for the investigation of insulin secretion ability was found to be 50 ug/mL of LP. At this concentration, maximum insulin secretion was observed in the INS cells treated with LP extract steamed for 3 h (3-SLP) with two repeated steps (3 h steaming and 24 h air-dried) carried out 9 times (9-SALP); no significant changes in viability were detected in any of the treated cells. Additionally, the expression and phosphorylation levels of most components in the insulin receptor signaling pathway were increased significantly in the majority of cells treated with steaming-processed LP as compared to the cells treated with LP prepared without steaming. With regard to glucose transporter (GLUT) expression, alterations of steaming time induced similar responses on the expression levels of GLUT-2 and GLUT-3. However, differences in steaming frequency were also shown to induce dose-dependent responses in the expression level of GLUT-2 only; no significant differences in GLUT-3 expression were detected under these conditions. Furthermore, these responses observed in vitro were similarly detected in STZ-induced diabetic mice. 24-SLP and 9-SALP treatment applied for 14 days induced the down-regulation of glucose concentration and upregulation of insulin concentration. Therefore, these results indicated that the steaming processed LP may contribute to the relief of diabetes symptoms and should be regarded as an excellent candidate for a diabetes treatment.

The multi-herbal medicine Gongjin-dan enhances memory and learning tasks via NGF regulation

Nerve growth factor (NGF) decreases degeneration of cholinergic neurons, improves memory loss, and increases long-term potentiation and learning tasks. Therefore, NGF mimetics or NGF inducers may be important targets for the treatment of various neurodegenerative disorders. Traditionally, Gongjin-dan (GJD) has been used clinically for the treatment of central nervous system disorders. In this study, we examined the effects of GJD on NGF mimetic activity in PC12 cells and the induction of NGF secretion in primary astrocytes. Moreover, we also measured neuron survival by MAP-2 staining in an immobilization stress rat model and induction of long-term potentiation by the MEA system in rat hippocampus slices treated with dexamethasone. The behavioral syndrome by novel object test was also performed in mice. GJD increased neurite outgrowth in PC12 cells and NGF secretion in primary astrocytes. Also, it reduced neuronal cell death and increased long-term potentiation in the rat hippocampus. Moreover, the number of entries, the time spent and the distance moved in the center area of the test region by the mice was increased by oral administration of GJD in comparison with the distance moved over the total area. These data suggest that administration of GJD may improve memory and learning tasks via NGF regulation, and that it may have a potential for multiple function neuroprotection via NGF regulation.

Liriopis tuber inhibit OVA-induced airway inflammation and bronchial hyperresponsiveness in murine model of asthma

Liriope platyphylla is one of the well-known herb used in oriental medicine for treatment asthma and bronchial and lung inflammation. Anti-asthmatic effects of Liriope platyphylla in the development of OVA-induced airway inflammation and murine asthma model have not been fully investigated in vivo. Asthma is a chronic inflammatory disease of the mucosa and is associated with excess production of Th2 cytokines and eosinophil accumulation in lung. To clarify the anti-inflammatory and anti-asthmatic effects of Liriope platyphylla, we examined the influence of liriopis tuber (LRT) on the development of pulmonary eosinophilic inflammation in murine model of asthma. Our results have shown that LRT were demonstrated on the accumulation of eosinophills into airways, with reduction of eosinophil, total lung leukocytes numbers by reduction IL-5, IL-13, IL-4 and IgE levels in the BALF and serum. Moreover, LRT decreased eosinophil CCR3 expression and CD11b expression in lung cells. These results indicate that LRT has a deep inhibitory effects on airway inflammation and hyperresponsiveness in murine model of asthma and play an crucial role as a immunomodulator which possess anti-inflammatory and anti-asthmatic property by modulating the relationship between Th1/Th2 cytokine imbalance.