Optimization of diosgenin extraction from Dioscorea deltoidea tubers using response surface methodology and artificial neural network modelling.

INTRODUCTION: Dioscorea deltoidea var. deltoidea (Dioscoreaceae) is a valuable endangered plant of great medicinal and economic importance due to the presence of the bioactive compound diosgenin. In the present study, response surface methodology (RSM) and artificial neural network (ANN) modelling have been implemented to evaluate the diosgenin content from D. deltoidea. In addition, different extraction parameters have been also optimized and developed. MATERIALS AND METHODS: Firstly, Plackett-Burman design (PBD) was applied for screening the significant variables among the selected extraction parameters i.e. solvent composition, solid: solvent ratio, particle size, time, temperature, pH and extraction cycles on diosgenin yield. Among seven tested parameters only four parameters (particle size, solid: solvent ratio, time and temperature) were found to exert significant effect on the diosgenin extraction. Moreover, Box-Behnken design (BBD) was employed to optimize the significant extraction parameters for maximum diosgenin yield. RESULTS: The most suitable condition for diosgenin extraction was found to be solid: solvent ratio (1:45), particle size (1.25 mm), time (45 min) and temperature (45°C). The maximum experimental yield of diosgenin (1.204% dry weight) was observed close to the predicted value (1.202% dry weight) on the basis of the chosen optimal extraction factors. The developed mathematical model fitted well with experimental data for diosgenin extraction. CONCLUSIONS: Experimental validation revealed that a well trained ANN model has superior performance compared to a RSM model.

Comparison of ultrasound and microwave assisted extraction of diosgenin from Trigonella foenum graceum seed.

From the recent market trend, there is a huge demand for the bioactive compounds from various food matrices that could be capable enough to combat the emerging health effects in day-to-day life. Fenugreek is a well-known spice from ancient times for its medicinal and health benefits. In the present study, two methods of green extraction microwave (MAE) and ultrasound (UAE) assisted were studied in regard of extraction of fenugreek diosgenin. In this study, solvent type (acetone, ethanol, hexane and petroleum ether), solvent concentration (40, 60, 80 and 100%) and treatment time (1.5, 3.0, 4.5 and 6.0 min and 30, 40, 50 and 60 min for MAE and UAE method respectively) was varied to observe the effect of these parameters over extract yield and diosgenin content. The results of this study revealed that treatment time, type of solvent and its concentration and method adopted for extraction of diosgenin has significant effect. In relation with better yield extract and diosgenin content, the yield of fenugreek seed extract was 7.83% with MAE and 21.48% with UAE of fenugreek seed powder at 80% ethanol concentration at 6 and 60 min respectively. The content of diosgenin was observed in fenugreek seed powder extract was 35.50 mg/100 g in MAE and 40.37 mg/100 g in UAE with 80% ethanol concentration at 6 and 60 min respectively. The overall range of yield of fenugreek extract was varied from 1.04% to 32.48% and diosgenin content was 15.82 mg/100 g to 40.37 mg/100 g of fenugreek seed powder including both extraction methods. This study revealed that UAE would impose better ways for preparing fenugreek extract and observing diosgenin content from fenugreek seeds.

Influence of Soil Variation on Diosgenin Content Profile in Costus speciosus from Indo-Gangetic Plains.

Costus speciosus is a rich source of commercially important compound Diosgenin, distributed in different regions of India. The present investigation was aimed to quantify diosgenin through High Performance Thin Layer Chromatography in 34 germplasms of Costus speciosus and also to identify the superior sources and to correlate the macronutrients of rhizospheric soil. The starch content varied in microscopic examination and correlated inversely (r=-0.266) with diosgenin content. Findings revealed that the extraction process with acid hydrolysis yielded higher diosgenin content (0.15-1.88 %) as compared to non-hydrolysis (0.009-0.368 %) procedure. Germplasms from Uttar Pradesh (NBCS-4), Jharkhand (NBCS-39) and Bihar (NBCS-2) were identified as elite chemotypes based on hierarchical clustering analysis. The phosphorous content of respective rhizospheric soil correlated positively (r=0.742) with diosgenin content. Findings of present study are useful to identify the new agrotechniques. The elite germplasms can also be used as quality planting material for large scale cultivation in order to assure a sustained supply to the herbal drug industry.

Evaluation of antioxidant, anti-inflammatory and anticancer activities of diosgenin enriched Paris polyphylla rhizome extract of Indian Himalayan landraces.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional medicinal plants have gained attention as a potential therapeutic agent to combat cancer and inflammation. Diosgenin rich fresh extracts of Paris polyphylla rhizome from Indian Himalaya is traditionally used as wound healing, anti-bleeding, anti-inflammatory and anti-cancer agent by the folk healers. AIM OF THE STUDY: Present study was aimed to prepare two types of extracts from Paris polyphylla rhizome of Indian Himalayan landraces - 1. ethanolic extract of Paris polyphylla rhizome (EEPPR) and 2. Diosgenin enriched Paris polyphylla rhizome extract (DPPE), quantification of diosgenin content, and to evaluate their in vitro anti-oxidant, in vivo anti-inflammatory and in vitro cytotoxicity and anti-cancer activities of the DPPE. MATERIALS AND METHODS: Diosgenin content of EEPPR was quantified through GC-MS while diosgenin content of DPPE was quantified through HPTLC, and the diosgenin yield from EEPPR and DPPE were compared. In vitro antioxidant activities of DPPE were performed using DPPH, NOD, RP and SOD assay while in vivo anti-inflammatory activity of DPPE were evaluated in dextran induced hind paw edema in rats. In vitro cytotoxicity and anti-cancer activities of DPPE were evaluated in human breast cancer cell lines (MCF-7, MDA-MB-231), cervical cancer cell lines (HeLa) and Hep-2 cell lines. RESULTS: EEPPR obtained through cold extraction method using 70% ethanol showed maximum diosgenin content of 17.90% quantified through GC-MS while similar compounds pennogenin (3.29%), 7ß-Dehydrodiosgenin (1.90%), 7-Ketodiosgenin acetate (1.14%), and 7 ß-hydroxydiosgenin (0.55%) were detected in low concentration, and thus confirmed diosgenin as major and lead phytochemical. However, DPPE obtained through both cold and repeated hot extraction with the same solvent (70% ethanol) showed diosgenin content of 60.29% which is significantly higher (p < 0.001) than the diosgenin content in EEPPR. DPPE demonstrated significant in vitro antioxidant activities by dose-dependently quenched (p < 0.001) SOD free radicals by 76.66%, followed by DPPH (71.43%), NOD (67.35%), and RP (63.74%) at a max concentration of 2 µg/µl of ascorbic acid and test drugs with remarkable IC50 values (p < 0.01). Further, DPPE also showed potent anti-inflammatory activities by dose-dependently suppressed dextran induced paw edema in rats (p < 0.01) from 2 h to 4 h. DPPE suppressed the proliferation of MCF-7, MDA-MB-231, Hep-2 and HeLa cell lines. Maximum activity was observed in MCF-7 cells. The DPPE also induced apoptosis in MCF-7 cell lines as measured by AO/PI and DAPI staining, as well as DNA laddering, cell cycle analysis and phosphatidylserine externalization assay. The growth-inhibitory effect of DPPE on MCF-7 breast cancer cells was further confirmed from the colony-formation assay. DPPE upregulated expression of Bax and downregulated Bcl-2 and survivin mRNA transcripts. CONCLUSION: DPPE obtained through both cold and repeated hot extraction using ethanol showed significantly higher content of diosgenin than the diosgenin content detected in EEPPR. However, diosgenin yield of both the extracts (EEPPR & DPPE) clearly confirmed diosgenin as major and lead phytochemical of Paris polyphylla rhizome of Indian Himalayan landraces. Further, DPPE also demonstrated potent in vitro anti-oxidative and in vivo anti-inflammatory activities and showed in vitro cytotoxicity and significant anti-cancer (apoptosis) effects in MCF-7 breast cancer cells.

Methyl protodioscin from Polygonatum sibiricum inhibits cervical cancer through cell cycle arrest and apoptosis induction.

Methyl protodioscin (MPD) is a steroid saponin which has been well known for its pharmacological properties. Herein, we evaluated the anti-cancer activity of MPD for proliferation inhibition and apoptosis induction in Hela cells. MPD was purified from the rhizoma of Polygonatum sibiricum primarily and identified by HPLC, UPLC-TOF-MS/MS and NMR analysis, respectively. Results showed that MPD repressed cell proliferation at IC50 of 18.49 µM, altered cell morphology, arrested the cell cycle in G2/M phase, facilitated the generation of intracellular ROS and led to cell apoptosis in a concentration-dependent manner. Furthermore, MPD treatment promoted death receptor pathway and mitochondrial pathway efficiently. The inhibition of Caspase-8 and Caspase-9 proteins in these pathways abolished the apoptosis significantly, further demonstrated the mechanism of MPD-induced apoptosis. These findings offer novel information that MPD may be considered as a possible natural anti-cancerous agent in the form of functional foods or medicinal products.

Dioscin, a Steroidal Saponin Isolated from Dioscorea nipponica, Attenuates Collagen-Induced Arthritis by Inhibiting Th17 Cell Response.

Dioscin, a steroidal saponin isolated from Dioscorea nipponica Makino, has previously been shown to possess antiarthritic effects. However, the underlying mechanism is still elusive. Herein, we investigated the therapeutic effects of dioscin on collagen-induced arthritis (CIA) in DBA/1 mice and related mechanism. Cytokine production in CII-specific immune responses were measured by enzyme-linked immunosorbent assay (ELISA); Th17 cell-related gene expression, including IL-17A, ROR γτ and IL-23p19, were detected by qPCR analysis; Surface marker, T regulatory (Treg) cells and intracellular cytokines (IL-17A and IFN- γ ) were evaluated by flow cytometry. We performed Th17 cell differentiation assay in vitro. Results showed that, in vivo, dioscin treatment significantly reduced the severity of CIA, which was accompanied by decreased Th17 response, but not Th1 and Treg response; dioscin-treated mice also showed lower percentage of CD11b + Gr-1 + neutrophils; In vitro, dioscin treatment suppressed the differentiation of naive CD4 + T cells into Th17 cell and decreased IL-17A production. Collectively, our results indicate that dioscin exerts antiarthritic effects by inhibiting Th17 cell immune response.

Validation of a method for diosgenin extraction from fenugreek (Trigonella foenum-graecum L.).

BACKGROUND: Diosgenin is a very important plant secondary metabolite and raw material for the drug indus- try. Plant sources rich in diosgenin include yam (Dioscorea spp.) and fenugreek (Trigonella foenum-graecum L.). A method for diosgenin extraction from yam extracts has previously been validated, but its extraction from fenugreek plants still requires validation. In addition, all available methods require time-consuming additional purification steps. The present study was aimed at developing a low cost, less time-consuming single-step method for diosgenin extraction from fenugreek. METHODS: This study represents a method developed for diosgenin extraction from fenugreek plants without any additional/supportive purification methods such as chromatography or thin-layer chroma- tography. Diosgenin yield estimation and purity analysis by HPLC method, along with accuracy and preci- sion analysis, is presented. RESULTS: Five different fenugreek varieties were subjected to a newly developed diosgenin extraction method, and an HPLC chromatogram showed a single peak corresponding to diosgenin. Yield was determined by the standard curve method. Limit of detection (LOD) and limit of quantification (LOQ) for the assay were found to be 0.0312 and 0.102 μg, respectively; tcalculated for slope and other statistical parameters were found to be significant (P value < 0.001) for this method. CONCLUSIONS: We have developed a fast, accurate and low cost method for diosgenin extraction from fenu- greek. Although the authors have studied this method only in fenugreek plants, it could be applied to the extraction of a few other plant secondary metabolites, which will help researchers to save time and effort.

Molecular mechanism and inhibitory targets of dioscin in HepG2 cells.

Dioscin has been known for its anti-cancer activity; however, its detailed molecular mechanisms have not been studied so far. Herein, we evaluated the anti-cancer activity of dioscin for proliferation inhibition and apoptosis in HepG2 cancer cells. Initially, dioscin was purified and identified from Polygonatum sibiricum by HPLC, MS, and NMR analysis, respectively. Dioscin inhibited the cell multiplication at IC50 of 8.34 µM, altered the cell morphology, arrested the cell cycle in G2/M phase and led to considerable programmed cell death. Furthermore, it has efficiently promoted the mitochondrial pathway and death receptor pathway. The inhibition of Caspase-8 and Caspase-9 proteins in these pathways abolished the dioscin induced apoptosis significantly; while dioscin inhibited the PI3K/Akt/mTOR pathway. Moreover, dioscin exposure led to enhanced intracellular ROS generation and the mRNA expression of JNK gene which emphasized their involvement in the apoptosis process in HepG2 cells.

Influence of Nutritional Status on the Absorption of Polyphyllin I, an Anticancer Candidate from Paris polyphylla in Rats.

BACKGROUND AND OBJECTIVES: Protein-calorie malnutrition (PCM) is one of the most suffered complications in cancer patients. Polyphyllin I (PPI), a saponin isolated from rhizome of Paris polyphylla, is a potential candidate in cancer therapy. In this study, the influence of nutritional status on the absorption of PPI in rats was explored after oral administration. METHODS: PCM rats, namely mal-nourished (MN) rats, were induced from well-nourished (WN) rats by caloric restriction protocol. Intestinal absorption of PPI in WN and MN rats was evaluated by pharmacokinetic and intestinal perfusion methods. The potential mechanisms between two groups were investigated on the basis of intestinal permeability, intestinal efflux and PPI's depletions in vivo. The intestinal permeability was analyzed by determining the concentration of paracellular marker transport in serum and the expression of junction proteins in intestine. The intestinal efflux was evaluated through comparing the protein level of P-glycoprotein (P-gp) in intestine, and the depletions of PPI and/or generation of its metabolites in liver and intestines were analyzed by liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS) method. RESULTS: Compared to WN rats, the oral systemic exposure of PPI was significantly increased in MN rats, evidenced by significant enhancement of maximum plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC0-60h) by more than 2.51- and 3.71-folds as well as terminal elimination half-life (t1/2) prolonged from to 7.3 to 14.1 h. Further studies revealed that the potential mechanism might be associated with combined contribution of improved intestinal absorption and depressed deglycosylation of PPI in MN rats. Furthermore, enhanced intestinal absorption of PPI was benefited from increased intestinal permeability and decreased intestinal efflux in MN rats. Meanwhile, the former manifested as increased transport of paracellular marker and decreased junction proteins levels, while the later evidenced by reduced P-gp expression. CONCLUSIONS: The oral exposure of PPI was enhanced in MN rats, which suggested that nutritional status alters the absorption of PPI, and thus the dosage of PPI should be modified during the treatment of cancer patient with PCM.

Effect and mechanism of dioscin from Dioscorea spongiosa on uric acid excretion in animal model of hyperuricemia.

ETHNOPHARMACOLOGY RELEVANCE: Dioscin, a spirostane glycoside, the rhizoma of Dioscorea septemloba (Diocoreacea) is used for diuresis, rheumatism, and joints pain. Given the poor solubility and stability of Dioscin, we proposed a hypothesis that Dioscin's metabolite(s) are the active substance(s) in vivo to contribute to the reducing effects on serum uric acid levels. AIM OF THE STUDY: The aim of this study is to identify the active metabolite(s) of Dioscin in vivo and to explore the mechanism of its antihyperuricemic activity. MATERIALS AND METHODS: After oral administration of Dioscin in potassium oxonate (PO) induced hyperuricemia rats and adenine-PO induced hyperuricemia mice models, serum uric acid and creatinine levels, clearance of uric acid and creatinine, fractional excretion of uric acid, and renal pathological lesions were determined were used to evaluate the antihyperuricemic effects. Renal glucose transporter-9 (GLUT-9) and organic anion transporter-1 (OAT-1) expressions were analyzed by western blotting method. Renal uric acid excretion was evaluated using stably urate transporter-1 (URAT-1) transfected human epithelial kidney cell line. Intestinal uric acid excretion was evaluated by measuring the transcellular transport of uric acid in HCT116 cells. RESULTS: In hyperuricemia rats, both 25 and 50mg/kg of oral Dioscin decreased serum uric acid levels over 4h. In the hyperuricemia mice, two weeks treatment of Dioscin significantly decreased serum uric acid and creatinine levels, increased clearance of uric acid and creatinine, increased fractional excretion of uric acid, and reduced renal pathological lesions caused by hyperuricemia. In addition, renal GLUT -9 was significantly down-regulated and OAT-1 was up-regulated in Dioscin treated hyperuricemia mice. Dioscin's metabolite Tigogenin significantly inhibited uric acid re-absorption via URAT1 from 10 to 100µM. Diosgenin and Tigogenin increased uric acid excretion via ATP binding cassette subfamily G member 2 (ABCG2). CONCLUSION: Decreasing effect of Dioscin on serum uric acid level and enhancing effect on urate excretion were confirmed in hyperuricemia animal models. Tigogenin, a metabolite of Dioscin, was identified as an active substance with antihyperuricemic activity in vivo, through inhibition of URAT1 and promotion of ABCG2.

Anti- trachea inflammatory effects of diosgenin from Dioscorea nipponica through interactions with glucocorticoid receptor α.

Asthma is a heterogeneous disease characterized by symptoms of chronic inflammation and airway structural and functional changes. It affects about 300 million people worldwide and causes 250 000 deaths annually, but its symptoms can be greatly relieved by regular use of inhaled glucocorticoids (GCs). GCs exert their function through interacting with glucocorticoid receptors (GRs). Diosgenin is a naturally occurring steroidal saponin abundantly present in many medicinal plants, including Dioscorea nipponica, which shares a similar steroidal structure with GC. In this study, ovalbumin (OVA)-induced asthmatic mice and primary tracheal epithelial cells (TECs) were used as research models. ELISAs were applied to measure the secretion of TNF-α, IL-1ß, and IL-6, while quantitative PCR and western blotting were applied to evaluate expression of GRs SLPI, TTP, GILZ, MKP-1, and NF-κB. Our data demonstrated that diosgenin suppressed the secretion of TNF-α, IL-1ß, and IL-6 by enhancing the expression of GRs, SLPI, GILZ, and MKP-1, and inhibiting the expression of HSP70. These data provide some evidence on the molecular mechanism of diosgenin, which might facilitate its clinical applications.

Dioscin alleviates dimethylnitrosamine-induced acute liver injury through regulating apoptosis, oxidative stress and inflammation.

In our previous study, the effects of dioscin against alcohol-, carbon tetrachloride- and acetaminophen-induced liver damage have been found. However, the activity of it against dimethylnitrosamine (DMN)-induced acute liver injury remained unknown. In the present study, dioscin markedly decreased serum ALT and AST levels, significantly increased the levels of SOD, GSH-Px, GSH, and decreased the levels of MDA, iNOS and NO. Mechanism study showed that dioscin significantly decreased the expression levels of IL-1ß, IL-6, TNF-α, IκBα, p50 and p65 through regulating TLR4/MyD88 pathway to rehabilitate inflammation. In addition, dioscin markedly up-regulated the expression levels of SIRT1, HO-1, NQO1, GST and GCLM through increasing nuclear translocation of Nrf2 against oxidative stress. Furthermore, dioscin significantly decreased the expression levels of FasL, Fas, p53, Bak, Caspase-3/9, and upregulated Bcl-2 level through decreasing IRF9 level against apoptosis. In conclusion, dioscin showed protective effect against DMN-induced acute liver injury via ameliorating apoptosis, oxidative stress and inflammation, which should be developed as a new candidate for the treatment of acute liver injury in the future.

Low pressure steam expansion pretreatment as a competitive approach to improve diosgenin yield and the production of fermentable sugar from Dioscorea zingiberensis C.H. Wright.

Development of efficient pretreatment methods which can disrupt the peripheral lignocellulose and even the parenchyma cells is of great importance for production of diosgenin from turmeric rhizomes. It was found that low pressure steam expansion pretreatment (LSEP) could improve the diosgenin yield by more than 40% compared with the case without pretreatment, while simultaneously increasing the production of fermentable sugar by 27.37%. Furthermore, little inhibitory compounds were produced in LSEP process which was extremely favorable for the subsequent biotransformation of fermentable sugar to other valuable products such as ethanol. Preliminary study showed that the ethanol yield when using the fermentable sugar as carbon source was comparable to that using glucose. The liquid residue of LSEP treated turmeric tuber after diosgenin production can be utilized as a quality fermentable carbon source. Therefore, LSEP has great potential in industrial application in diosgenin clean production and comprehensive utilization of turmeric tuber.

Antifungal activity of secondary plant metabolites from potatoes (Solanum tuberosum L.): Glycoalkaloids and phenolic acids show synergistic effects.

AIMS: To study the antifungal effects of the potato secondary metabolites α-solanine, α-chaconine, solanidine and caffeic acid, alone or combined. METHODS AND RESULTS: Resistance to glycoalkaloids varied among the fungal species tested, as derived from minimum inhibitory concentrations assays. Synergistic antifungal activity between glycoalkaloids and phenolic compounds was found. Changes in the fluidity of fungal membranes caused by potato secondary plant metabolites were determined by calculation of the generalized polarization values. The results partially explained the synergistic effect between caffeic acid and α-chaconine and supported findings on membrane disruption mechanisms from previous studies on artificial membranes. LC/MS analysis was used to determine variability and relative amounts of sterols in the different fungal species. Results suggested that the sterol pattern of fungi is related to their resistance to potato glycoalkaloids and to their taxonomy. CONCLUSION: Fungal resistance to α-chaconine and possibly other glycoalkaloids is species dependent. α-Chaconine and caffeic acid show synergistic antifungal activity. The taxonomic classification and the sterol pattern play a role in fungal resistance to glycoalkaloids. SIGNIFICANCE AND IMPACT OF THE STUDY: Results improve the understanding of the antifungal mode of action of potato secondary metabolites, which is essential for their potential utilization as antifungal agents in nonfood systems.

A new quantitation method of protodioscin by HPLC-ESI-MS/MS in rat plasma and its application to the pharmacokinetic study.

A specific high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS method) was established for determining the concentration of protodioscin (PG) in rat plasma after intragastric administration of its standard form. Ginsenoside Rb1 was selected as the internal standard (IS). The plasma sample was prepared using one-step deproteinization procedure by adding three parts of acetonitrile to precipitate proteins. The chromatographic separation was accomplished on an Inersil ODS-3 C18 column (250 × 4.6 mm, 5 µm) with a mobile phase composed with acetonitrile and water containing 0.1% formic acid under a gradient elution mode at a flow rate of 1 mL min(-1). A 3:1 portion of the eluent after a microsplit was detected on a triple quadrupole tandem mass spectrometer coupled with electrospray ionization (ESI) in positive ion and multiple reaction monitoring (MRM) scanning modes. The mass transitions were selected as 888.1 → 1050.2 for PG and 948.2 → 1110.3 for IS, respectively. After careful validation, the plasma samples were always stable under different storage conditions. These analytical results rendered sensitive, selective, and reliable values by this established method which displayed high accuracy, adequate extracted recoveries, and almost negligible matrix effects. This method was applied to the pharmacokinetic studies on PG level in the rat plasma and its pharmacokinetic effect. The results of our studies suggest that the present method may be a useful tool for further clinical study of PG.

Anti-inflammatory, antioxidant and antiangiogenic activities of diosgenin isolated from traditional medicinal plant, Costus speciosus (Koen ex.Retz.) Sm.

Costus speciosus is an important medicinal plant widely used in several indigenous medicinal formulations. The present study was conducted to evaluate the in vitro anti-inflammatory, antioxidant and antiangiogenic activities of diosgenin isolated from C. speciosus. The diosgenin was isolated from C. speciosus by HPTLC and its biological activities were studied by different protocols. The results demonstrated that LPS stimulated TNF-α generation in RAW 264.7 macrophage culture supernatant up to 3.7-fold of the control and that sample treatment (50 µg/mL) resulted in a highly significant inhibitory effect on LPS-stimulated TNF-α (p < 0.01) in a similar manner to methotrexate inhibitory effect. The tested sample possessed an effective antioxidant scavenging affinity against DPPH radicals as compared with the standard antioxidant activity of vitamin C. The results presented here may suggest that diosgenin isolated from C. speciosus possess anticancer, apoptotic and inhibitory effects on cell proliferation.

Inhibition of dioscin on Saprolegnia in vitro.

As one of the most serious pathogens in the freshwater aquatic environment, Saprolegnia can induce a high mortality rate during the fish egg incubation period. This study investigated the anti-Saprolegnia activity of a total of 108 plants on Saprolegnia parasitica in vitro and Dioscorea collettii was selected for further studies. By loading on an open silica gel column and eluting with petroleum ether-ethyl acetate-methanol, dioscin (C45H72O16) was isolated from D. collettii. Saprolegnia parasitica growth was inhibited significantly when dioscin concentration was more than 2.0 mg L(-1). When compared with formalin and hydrogen peroxide, dioscin showed a higher inhibitory effect. As potential inhibition mechanisms, dioscin could cause the S. parasitica mycelium morphologic damage, dense folds, or disheveled protuberances observed by field emission scanning electron microscopy and the influx of Propidium iodide. The structural changes in the treated mycelium were indicative of an efficient anti-Saprolegnia activity of dioscin. The oxidative stress results showed that dioscin also accumulated reactive oxygen species excessively and increased total antioxidant and superoxide dismutase activity. These situations could render S. parasitica more vulnerable to oxidative damage. Additionally, when dioscin concentration was less than 2.0 mg L(-1), the survival rate of embryos was more than 70%. Therefore, the use of dioscin could be a viable way of preventing and controlling saprolegniasis.

Molecular mechanisms of Polyphyllin I-induced apoptosis and reversal of the epithelial-mesenchymal transition in human osteosarcoma cells.

Osteosarcoma is a most common highly malignant bone tumor in children and adolescents. Polyphyllin I (PPI) is an ethanol extraction from Paris polyphylla Smith var.yunnanensis (Franch.) Hand.-Mazz, which belongs to antipyretic-detoxicate family and has been used as a natural medicine in the treatment of infectious disease and cancer in China for centuries. The proteasome activity inhibitory and anti-osteosarcoma effects of PPI have not been known. Here we found PPI exhibited a selective inhibitory effect on proteasomal chymotrypsin (CT)-like activity, both in purified human proteasome and in cultured osteosarcoma cellular proteasome, and caused an accumulation of ubiquitinated proteins. PPI also inhibited viability, proliferation, migration, and invasion of MG-63, Saos-2, and U-2 OS osteosarcoma cells and resulted in S phase arrest and apoptosis. Furthermore, we explored the molecular targets involved. Exposure of osteosarcoma cells to PPI caused an inactivation of the intrinsic nuclear factor κB (NF-κB) and activation of unfolded protein response (UPR)/endoplasmic reticulum (ER) stress signaling cascade in osteosarcoma cells, followed by down-regulation of anti-apoptotic proteins, with up-regulation of pro-apoptotic proteins. We also demonstrated down-regulation of c-Myc, Cyclin B1, Cyclin D1, and CDK1, which are involved in the cell cycle and growth. Finally, we identified down-regulation of Vimentin, Snail, Slug, and up-regulation of E-cadherin, which are integral proteins involved in epithelial-mesenchymal transition (EMT). Taken together, our data provide insights into the mechanism underlying the anticancer activity of PPI in human osteosarcoma cells.

An Efficient Purification Method for Quantitative Determinations of Protodioscin, Dioscin and Diosgenin in Plasma of Fenugreek-Fed Mice.

An efficient purification method for simultaneous recovery of polar saponins, protodioscin (PD) and dioscin (DC), and non-polar aglycon, diosgenin (DG), from plasma of mice fed diets containing seed flours of fenugreek (Trigonella foenum-graecum) was established for subsequent quantitative analysis by LC-ESI-MS/MS. Mice plasma samples were first deproteinated by addition of acetonitrile, and the supernatant was applied to a carbon-based solid phase extraction tube. After successive washing with methanol and 35% chroloform/methanol (v/v), PD, DC and DG were eluted simultaneously with 80% chroloform/methanol (v/v). The eluate was evaporated to dryness, and re-dissolved in 80% methanol (v/v). The filtered sample was analyzed with an LC-ESI-MS/MS system. After the purification procedure, recovery rates between 89.3 to 117.4% were obtained without notable ion suppression or enhancement. The use of internal standards was therefore not necessary. The utility of the method was demonstrated by analyzing plasma of mice from a fenugreek feeding study.

Efficacy of natural diosgenin on cardiovascular risk, insulin secretion, and beta cells in streptozotocin (STZ)-induced diabetic rats.

Costus igneus, has been prescribed for the treatment of diabetic mellitus in India for several years. The aim of this study is to investigate the effects of plant derived diosgenin on cardiovascular risk, insulin secretion, and pancreatic composition through electron microscopical studies of normal and diabetic rats. Diosgenin at a dose of 5 or 10mg/kg per body weight (bw) was orally administered as a single dose per day to diabetic induced rats for a period of 30 days. The effect of diosgenin on blood glucose, HbA1c, PT, APTT, Oxy-LDL, serum lipid profile, electron microscopical studies of pancreas, antioxidant enzymes (in liver, kidney, pancreas) and hepatoprotective enzymes in plasma and liver were measured in normal and diabetic rats. The results showed that fasting blood glucose, PT, APTT, Oxy-LDL, TC, TG, LDL, ALT, AST, ALP, glucose-6-phosphatase, fructose-1,6-bisphosphatase and LPO levels were significantly (p<0.05) increased, whereas HDL, SOD, CAT, GSH and the glycolytic enzyme glucokinase levels were significantly (p<0.05) decreased in the diabetes induced rats and these levels were significantly (p<0.05) reversed back to normal in diabetes induced rats after 30 days of treatment with diosgenin. Electron microscopical studies of the pancreas revealed that the number of beta cells and insulin granules were increased in streptozotocin (STZ) induced diabetic rats after 30 days of treatment with diosgenin. In conclusion, the data obtained from the present study strongly indicate that diosgenin has potential effects on cardiovascular risk, insulin secretion and beta cell regeneration in STZ induced diabetic rats, these results could be useful for new drug development to fight diabetes and its related cardiovascular diseases.