Polygonatum Odoratum Research Articles

Effects of constant low temperature on cold resistance of different strains Polygonatum odoratum

In this paper, the five strains of Polygonatum odoratum were used as the experimental materials to test the supercooling point, freezing point, the degree of supercooling, the transition stage time, cooling time and water composition of the plant tissue. The cold resistance of P. odoratum was analyzed with the Gray Correlation Method. The results showed that the cold resistances of the five strains of P. odoratum were different, and the water content of plant tissue had some relevance with freezing point and supercooling point, whereas, it could not be measured when the moisture content was too low. The order of cold resistance of the five strains of P. odoratum was ZJCY, DYYZ, XYYZ, CYYZ and JZ I.

Two New Homoisoflavanones from the Rhizome of Polygonatum odoratum

Two new homoisoflavanones (1 and 2) were isolated from the rhizome of Polygonatum odoratum. The structures of the compounds were elucidated by spectroscopic methods.

Screening of Plants with Inhibitory Activity on Cellular Senescence

In this study, the effect of plant extract on the senescence action and cell survival rate in two types of cells, in which aging was derived by adriamycin, was analyzed to find the materials for suppressing cell senescence from natural resources. The results are as follows. For human umbilical vein endothelial cells (HUVECs), the fruit of Physalis angulate L. and the aerial part of Synurus deltoides (Aiton) Nakai showed excellent cell-senescence inhibition activities in a treatment concentration-dependent manner, demonstrating the high possibility for utilization as a material for prevention and treatment for vascular diseases. The water extract from the root of Polygonatum odoratum var. pluriflorum for variegatum Y. N. Lee showed potent cell-senescence inhibitory effect for human dermal fibroblasts (HDFs). Thus it is considered that the additional study on the plant needs for elucidating the possible utilization as material for skin health improvement.

둥굴레 '건강백세'의 기내 대량번식

경상남도 농업기술원에서 육성된 둥굴레 '건강백세(Polygonatum odoratum cv. Gungangbeaksea)'를 분양받아 배양하였다. 둥굴레 지하경 절편체를 MS 배지에 BA 3.0 mg/L가 첨가된 배지에서 배양하면서 증식된 부정신초괴를 실험재료로 사용하였다. 배양 8주후, 신초의 증식은 TDZ 3.0 mg/L 첨가배지에서 2.8개로 가장 많았으며 생체중도 절편체당 2.32 g으로 가장 높게 나타났다. TDZ와 NAA가 첨가된 배지에서는 신초 및 부정신초괴의 증식이 다소 증가하였다. TDZ 3.0 mg/L와 NAA 5.0 mg/L 첨가배지, TDZ 5.0 mg/L와 NAA 3.0 mg/L 첨가배지에서 신초수 3.7개, 생체중 2.9 g으로 다소 증가하였다. MS 염류농도가 높아질수록 신초 및 부정신초괴의 증식은 저조하였다. 그러나 sucrose 농도가 3%에서 7%로 증가함에 따라 신초수, 생체중 및 부정신초괴의 형성이 증가하였다. 뿐 만 아니라 둥굴레 부정신초절편체에서 신초 및 부정신초괴의 증식은 MS 배지에 TDZ와 NAA 3.0~5.0 mg/L와 sucrose 7%가 첨가된 배지가 적합하였다. 발근율은 IBA 3.0 mg/L 또는 NAA 2.0 mg/L 첨가배지에서 80% 이상으로 높았으며, 발근된 식물체의 순화는 vermiculite 단용 또는 perlite, vermiculite 1:1 혼용처리에서 순화율 100%로 적합하였다. The Polygonatum odoratum cv. Gungangbeaksea, bred in Gyeongsangnam-Do Agricutural Research & Extension Service, was cultured in vitro for micropropagate rapidly through the culture of rhizome explants (<TEX>$5{\times}5mm$</TEX>). The <TEX>$7{\times}7mm$</TEX> explants of adventitious multi-bud clusters (AMC), obtained through the culture of rhizome explants (MS + 3.0 mg/L BA) were cultured on MS media with BA and TDZ. The shoot multiplication was favorable on the MS medium containing 3.0 mg/L TDZ with 2.8 in shoot number. But the formation of AMC was low in all media tested. The explants of AMC were cultured on MS media containing 1.0~5.0 mg/L TDZ and NAA to multiplicate AMC more. The formation of AMC was a little more stimulated on combined MS media of TDZ and NAA, than that with TDZ alone. The multiplication of shoots and AMC was favorable on MS media with 3.0 mg/L TDZ and 5.0 mg/L NAA, and 5.0 mg/L TDZ and 3.0 mg/L NAA. As the concentration of MS salts increased, the formation of AMC was decreased. But the formation of AMC was more stimulated, as the concentration of sucrose increased to 7%. Therefore, the multiplication of shoots and AMC was suitable on media containing 3.0~5.0 mg/L TDZ and NAA, and 7% of sucrose. The explants of AMC were rooted on media with 3.0 mg/L IBA, or 2.0 mg/L NAA with more than 80% in rooting ratio. The plantlets were treated at <TEX>$5^{\circ}C$</TEX> for 8 weeks, and cultured ex vitro for 8 weeks. The survival ratio of plantlets were 100% in vermiculite, and the mixed soil with perlite 1 volumn and vermiculite 1 volumn.

Polygonatum odoratum lectin induces apoptosis and autophagy via targeting EGFR-mediated Ras-Raf-MEK-ERK pathway in human MCF-7 breast cancer cells

Polygonatum odoratum lectin (POL), a mannose-binding GNA-related lectin, has been reported to display remarkable anti-proliferative and apoptosis-inducing activities toward a variety of cancer cells; however, the precise molecular mechanisms by which POL induces cancer cell death are still elusive. In the current study, we found that POL could induce both apoptosis and autophagy in human MCF-7 breast cancer cells. Subsequently, we found that POL induced MCF-7 cell apoptosis via the mitochondrial pathway. Additionally, we also found that POL induces MCF-7 cell apoptosis via EGFR-mediated Ras-Raf-MEK-ERK pathway, suggesting that POL may be a potential EGFR inhibitor. Finally, we used proteomics analyses for exploring more possible POL-induced pathways with EGFR, Ras, Raf, MEK and ERK, some of which were consistent with our in silico network prediction. Taken together, these results demonstrate that POL induces MCF-7 cell apoptosis and autophagy via targeting EGFR-mediated Ras-Raf-MEK-ERK signaling pathway, which would provide a new clue for exploiting POL as a potential anti-neoplastic drug for future cancer therapy.

Optimization and Composition of Volatile Oil from Polygonatum odoratum (Mill Druce) using Supercritical Fluid Extraction

Purpose: To determine the effects of temperature, pressure and extraction time on oil yield obtained from Polygonatum odoratum as well as the optimum processing conditions for supercritical carbon dioxide (CO2) extraction.Methods: Supercritical CO2 extraction technology was adopted in this experiment to study the process of extraction of volatile oil from Polygonatum odoratum while gas chromatograph-mass spectrometer (GC-MS) technique was employed to analyze the chemical composition of the volatile oil. Response surface methodology (RSM) was applied to optimize supercritical CO2 process conditions.Results: The determined optimal conditions were as follows: extraction pressure, 27 MPa; extraction temperature, 50 °C; and extraction time, 97.10 min. Under these conditions, the predicted yield of Polygonatum volatile oil was 2.04 % as against an actual oil yield of 2.02 % of the seeds. GC-MS analysis showed that the extract obtained by supercritical CO2 extraction was richer in fatty acids and flavoring substances than that obtained by hydrodistillation.Conclusion: Using RSM can optimize conditions of Polygonatum volatile oil. This provides a scientific basis for further research and development of healthy foods, as well as comprehensive utilization of Polygonatum odoratum.Keywords: Polygonatum odoratum, Volatile oil, Supercritical fluid, Carbon dioxide, Extraction, Gas chromatograph-mass spectrometer

Steroidal sapogenins and glycosides from the fibrous roots of Polygonatum odoratum with inhibitory effect on tissue factor (TF) procoagulant activity

Six new spirostane glycosides (1–6), named polygodosides A–F, one new furostanol glycoside, polygodoside G (7), one new cholestane glycoside, polygodoside H (8), and one new steroidal sapogenin, polygodosin A (9), together with thirteen known compounds (10–22) were isolated from a 90% MeOH extract of the fibrous roots of Polygonatum odoratum (Mill.) Druce. The structures of new compounds were elucidated by extensive 1D and 2D NMR spectroscopic analyses and mass spectrometry. The effects on TF procoagulant activity in THP-1 cells were tested for most of the compounds.

Molecular switch role of Akt in Polygonatum odoratum lectin-induced apoptosis and autophagy in human non-small cell lung cancer A549 cells.

Polygonatum odoratum lectin (POL), isolated from traditional Chinese medicine herb (Mill.) Druce, has drawn rising attention due to its wide biological activities. In the present study, anti-tumor effects, including apoptosis- and autophagy-inducing properties of POL, were determined by a series of cell biology methods such as MTT, cellular morphology observation, flow cytometry, immunoblotting. Herein, we found that POL could simultaneously induce apoptosis and autophagy in human non-small cell lung cancer A549 cells. POL initiated apoptosis through inhibiting Akt-NF-κB pathway, while POL triggered autophagy via suppressing Akt-mTOR pathway, suggesting the molecular switch role of Akt in regulating between POL-induced apoptosis and autophagy. Moreover, ROS was involved in POL-induced inhibition of Akt expression, and might therefore mediate both apoptosis and autophagy in A549 cells. In addition, POL displayed no significant cytotoxicity toward normal human embryonic lung fibroblast HELF cells. Due to the anti-tumor activities, POL might become a potent anti-cancer drug in future therapy, which might pave the way for exploring GNA-related lectins into effective drugs in cancer treatment.

English

Polygonatum odoratum is an important herbal medicine that is used in folk medicine for the treatment of various elements and its components are reported to have various biological effects. This study was conducted to evaluate the effects of topical application of ethanol leaf extract of this plant on the rate of wound healing closure and histology of healed wound. Four groups of male Sprague Dawley rats, all were experimentally wound in the posterior neck area. The animal groups were topically treated respectively with 0.4 ml of each vehicle (gum acacia), Intrasite gel, 100 and 200 mg/ml of ethanol leaf extract. Macroscopically, wound dressed with leaf extracts and Intrasite gel-treated group significantly healed earlier than those treated with vehicle, and the rate of wound healing was significantly accelerated by topical application of 200 mg/kg leaf extract. Histological analysis of healed wounds dresses with leaf extracts showed comparatively less scar width at wound closure and healed wound contained less inflammatory cells and more collagen with angiogenesis as compared to wounds dressed with vehicle. In conclusion, wounds dressed with leaf extracts significantly enhanced the acceleration of wound healing enclosure in rats. &nbsp; Key words: Polygonatum odoratum leaf, ethanol extract, wound healing, histology.

증자 둥굴레 추출물의 3T3-L1 지방세포에서 분화억제 및 지질강하 효과

Objectives : The purpose of this study was to investigate inhibitory effects of steamed Polygonatum odoratum extract (POE) on differentiation and adipogenesis in 3T3-L1 adipocytes. Methods : Polygonatum odoratum (P. odoratum) extract was extracted with ethyl acetate. Total phenolic and flavonoid contents in POE were measured for antioxidant activity. The spectrophotometric method was used to determine the DPPH and ABTS radical scavenging activity and ferric-reducing antioxidant potential (FRAP). MTT assay was examined for cell toxicity, oil red O staining was performed for intracelluar adipogenesis in differentiated 3T3-L1 adipocytes. Western blot analysis for measurement of CCAAT/enhancer-binding protein <TEX>${\alpha}$</TEX> (<TEX>$C/EBP{\alpha}$</TEX>), peroxisome proliferator-activated receptor<TEX>${\gamma}$</TEX> (<TEX>$PPAR{\gamma}$</TEX>) and AMP-activated protein kinase (AMPK) expressions were performed. Results : The results revealed that POE has antioxidant activities. Contents of total polyphenolics and flavonoids were <TEX>$50.83{\pm}1.52$</TEX> GAE mg/100g dry weight of POE and <TEX>$17.05{\pm}2.47$</TEX> RE mg/100g dry weight of POE, respectively. DPPH radical scavenging activity, and FRAP in 10 mg/ml concentration were <TEX>$92.1{\pm}0.6%$</TEX>, <TEX>$244.8{\pm}9.0{\mu}M$</TEX> Fe(II) and ABTS inhibition in 5 mg/ml concentration was <TEX>$84.8{\pm}4.1%$</TEX>. Treatment of POE in adipocytes inhibited the differentiation and adipogenesis of 3T3-L1 adipocytes compared to those of vehicle control. Additionally, protein expressions of <TEX>$C/EBP{\alpha}$</TEX> and <TEX>$PPAR{\gamma}$</TEX>, major transcription factor for the adipogenic genes, were significantly decreased compared to those of vehicle control (p<0.05). Futhermore, phosphorylation of AMPK was increased in 3T3-L1 adipocytes treated with POE compared to that of vehicle control (p<0.05). Conclusions : we demonstrate that steamed P. odoratum extract (POE) has potentiating antioxidant activities, inhibits differentiation and lipid accumulation and also induces energy expenditure in adipocytes, which may contribute to antiobesity property.

Microwave-assisted extraction technology optimization and antioxidative effect of polyphenols from Polygonatum odoratum

According to previous study of single variable test, an ultrasonic procedure for the extraction of Polygonatum odoratum ( Mill.) Druc polyphenols was established.A three- level- four- factor, Box- Behnken design ( BBD) of response surface methodology was employed in this study to optimize the factorial parameters ( micromave power, microwave time, ratio of solvents to raw material, and ethanol concentration) , and polyphenols yield was taken as the response of the design experiments. The scavenging rates of 1, 1- diphenyl- 2- picryl-hydrazil ( DPPH) radical and superoxide anion of P. odoratum polyphenols in vitro were determined. The results showed that optimal extraction conditions for extraction of P.odoratum polyphenols were found to be microwave power 329 W, microwave time 26 min, ratio of solvents to raw material 1∶34 ( g /mL) , and ethanol concentration 49%, respectively.Under these conditions, the yield of P.odoratum polyphenols was 67.40 mg /g.P.odoratum polyphenols showed excellent scavenging effect against DPPH radical and superoxide anion in vitro.The study revealed that microwave-assisted technology was suitable for extraction of P.odoratum polyphenols, which was simply and high efficient, and the regression model was reliable for yield prediction.Moreover, P.odoratum polyphenols extracted by this method exhibited strong antioxidant activity in vitro.

Optimization of Alkaline Extraction and Bioactivities of Polysaccharides from Rhizome ofPolygonatum odoratum

The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80°C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) > extraction temperature (°C, B) > NaOH concentration (M, A) > extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli.

Extracts of Rhizoma polygonati odorati prevent high-fat diet-induced metabolic disorders in C57BL/6 mice.

Polygonatum odoratum (Mill.) Druce belongs to the genus Polygonatum family of plants. In traditional Chinese medicine, the root of Polygonatum odoratum, Rhizoma Polygonati Odorati, is used both for food and medicine to prevent and treat metabolic disorders such as hyperlipidemia, hyperglycemia, obesity and cardiovascular disease. However, there is no solid experimental evidence to support these applications, and the underlying mechanism is also needed to be elucidated. Here, we examined the effect of the extract of Rhizoma Polygonati Odorati (ER) on metabolic disorders in diet-induced C57BL/6 obese mice. In the preventive experiment, the ER blocked body weight gain, and lowered serum total cholesterol (TC), triglyceride (TG) and fasting blood glucose, improved glucose tolerance test (GTT) and insulin tolerance test (ITT), reduced the levels of serum insulin and leptin, and increased serum adiponectin levels in mice fed with a high-fat diet significantly. In the therapeutic study, we induced obesity in the mice and treated the obese mice with ER for two weeks. We found that ER treatments reduced serum TG and fasting blood glucose, and improved glucose tolerance in the mice. Gene expression analysis showed that ER increased the mRNA levels of peroxisome proliferator-activated receptors (PPAR) γ and α and their downstream target genes in mice livers, adipose tissues and HepG2 cells. Our data suggest that ER ameliorates metabolic disorders and enhances the mRNA expression of PPARs in obese C57BL/6 mice induced by high-fat diet.

Isolation and structural elucidation of novel cholestane glycosides and spirostane saponins from Polygonatum odoratum

Much attention has been paid to cholestane-type steroidal glycosides because of their importance from the perspectives of both chemical diversity and significant biological activities. A phytochemical investigation of the rhizomes of Polygonatum odoratum (Liliaceae) resulted in the isolation of three novel cholestane-type steroidal glycosides (1–3) with unique Δ14,16-unsaturated D-ring structures as well as two novel spirostane-type steroidal saponins (4 and 5) and three known steroidal glycosides (6–8). Their structures were determined by various spectroscopic methods and chemical reactions. Steroidal saponin 7 showed significant antifungal activity against Candida albicans JCM1542 (MIC 3.1μg/mL) and Aspergillus fumigatus JCM1738 (MIC 6.3μg/mL).

ChemInform Abstract: A Dihydrochalcone (III) and Several Homoisoflavonoids from Polygonatum odoratum Are Activators of Adenosine Monophosphate‐Activated Protein Kinase.

ChemInformVolume 44, Issue 40 Natural Products ChemInform Abstract: A Dihydrochalcone (III) and Several Homoisoflavonoids from Polygonatum odoratum Are Activators of Adenosine Monophosphate-Activated Protein Kinase. Hong Bai, Hong Bai Inst. Mater. Med., Shandong Acad. Med. Sci., Jinan, Shandong 250062, Peop. Rep. ChinaSearch for more papers by this authoret al. et al., et al. et al. Inst. Mater. Med., Shandong Acad. Med. Sci., Jinan, Shandong 250062, Peop. Rep. ChinaSearch for more papers by this author Hong Bai, Hong Bai Inst. Mater. Med., Shandong Acad. Med. Sci., Jinan, Shandong 250062, Peop. Rep. ChinaSearch for more papers by this authoret al. et al., et al. et al. Inst. Mater. Med., Shandong Acad. Med. Sci., Jinan, Shandong 250062, Peop. Rep. ChinaSearch for more papers by this author First published: 12 September 2013 https://doi.org/10.1002/chin.201340210Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume44, Issue40October 1, 2013 RelatedInformation

A dihydrochalcone and several homoisoflavonoids from Polygonatum odoratum are activators of adenosine monophosphate-activated protein kinase

Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a major cellular energy sensor and master regulator of metabolic homeostasis; thus, AMPK plays a central role in studies on diabetes and related metabolic diseases. From the rhizomes of Polygonatum odoratum (Mill.) Druce, six homoisoflavonoids (1–6) and one dihydrochalcone (7) were isolated, and the structures of polygonatones A–D (4–7) were elucidated by various spectroscopic analyses. Compounds 1–7 were evaluated for their effect on AMPK activation. The amount of active phosphorylated AMPK and acetyl-CoA carboxylase in rat liver epithelial IAR-20 cells increased when the cells were incubated with the aforementioned compounds. Specifically, (3R)-5,7-dihydroxyl-6-methyl-8-methoxyl-3-(4′-hydroxylbenzyl)-chroman-4-one (1), (3R)-5,7-dihydroxyl-6,8-dimethyl-3-(4′-hydroxylbenzyl)-chroman-4-one (2), (3R)-5,7-dihydroxyl-6-methyl-3-(4′-hydroxylbenzyl)-chroman-4-one (3), and polygonatone D (7) exhibited significant activation effects.

Effect of Different Processing Methods on the Yield of Extracts and Antioxidant Activities of Polygonatum odoratum

In order to study the effect of different processing methods on Polygonatum odoratum,the yield and antioxidant activities of polysaccharides,ethanol extracts,crude total flavonoids and water extracts were determined and compared.The results showed that the yield of polysaccharides,ethanol extracts of alcohol-steam P.odoratum and crude total flavonoids,water extracts of honey-steam P.odoratum were the higher than un-processed one,which were improved by 43.86%,29.53%,49.46% and 34.66%,respectively.The polysaccharides and water extracts of alcohol-steam P.odoratum exhibited the best DPPH scavenging activity at the same concentration than other samples with the IC50/DPPH=0.345±0.019 and 0.441±0.022 mg·mL-1,respectively.The crude total flavonoids and ethanol extracts of honey-steam P.odoratum exhibited the best DPPH scavenging activity at the same concentration than other samples with the IC50/DPPH=0.047±0.011 and 0.199±0.036 mg·mL-1,respectively.The DPPH scavenging activity of crude total flavonoids of honey-steam P.odoratum was higher(90.29%) than other extracts at the concentration of 1 mg·mL-1,which was higher than the rutin and quercetin at the concentration of 0.05 mg·mL-1.Both processing methods improved the total reductive ability of polysaccharides,crude total flavonoids and water extracts,while reduced the total reductive ability of ethanol extracts.

Chemical composition and physicochemical properties of dietary fiber from Polygonatum odoratum as affected by different processing methods

The dietary fibers were isolated from Polygonatum odoratum processed by different methods including steam processing (DFPS) and drying in sunshine (DFDS). The physicochemical and functional properties of dietary fibers were comparatively studied. Results showed that the fiber extracts from P. odoratum had a high amount of total dietary fiber (TDF) (97.92%–98.40%) and insoluble dietary fiber (IDF) (88.12%–92.90%), which resulted in the high swelling power, water-holding capacity (WHC) and oil-holding capacity (OHC). DFPS displayed significantly higher OHC (24.17g/g) and cation-exchange capacity (CEC) (887.35mequiv/kg) than DFDS (16.48g/g for OHC and 265.46mequiv/kg for CEC, respectively). However, DFDS exhibited significantly higher WHC (23.94g/g) and swelling power (17.54ml/g) in comparison to DFPS fiber (21.14g/g for WHC and 9.81ml/g for swelling power, respectively). The monosaccharide composition of DFDS consisted of arabinose, xylose, sorbose, mannose and galactose with the molecular ratio of 1.00:1.21:9.61:2.41:4.45. The monosaccharide molecular ratio of DFPS was 1.00:1.52:13.86:2.87:5.81. The WHC, SP and OHC of DFPS and DFDS were significantly higher than those of cellulose. P. odoratum might be a good food resource for dietary fiber. Different kinds of processing methods could be selected depending on the purpose of food products.

Antioxidant activities of different extracts and homoisoflavanones isolated from the Polygonatum odoratum

The antioxidant activities of five extracts from Polygonatum odoratum rhizomes were measured by three antioxidant assays in vitro. The crude flavonoid extracts (FE) exhibited the strongest antioxidant activity among all extracts with IC50/DPPH = 0.06 ± 0.035 mg mL−1, IC50/OH = 0.68 ± 0.030 mg mL−1 and reducing power/Abs125 µg mL−1 = 0.56 ± 0.033, respectively. In order to identify functional antioxidants, two C-methylated homoisoflavanones were isolated and purified from FE and their structures were identified by spectrometric techniques as 3-(4′-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4-one (1) and 3-(4′-hydroxyl-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one (2). Based on the results, both compounds had significant antioxidant activities on DPPH radical and reducing power but no effect on hydroxyl radical. The antioxidant activity of compound 1 (IC50/DPPH = 5.90 ± 0.150 µg mL−1) was nearly twofold stronger than compound 2 (IC50/DPPH = 11.64 ± 0.296 µg mL−1), and there was no significant difference between compound 1 and rutin (IC50/DPPH = 5.79 ± 0.140 µg mL−1).

Saponin rich fractions from Polygonatum odoratum (Mill.) Druce with more potential hypoglycemic effects

AimsThe root of Polygonatum odoratum (YuZhu), also a medicinal food has long been used for the treatment of diabetes. The objective of the study was to characterize the anti-diabetic active fractions or compounds in this herb. Materials and methodsFractions with a different polarity were prepared by solvent extraction and macroporous absorptive resin (D101) column and their anti-diabetic potentials were evaluated by glucose uptake in HepG2 cells and STZ-induced diabetic rats. In addition, α-glycosidase inhibitory activities of active fractions were measured in vitro and chemical compositions including saponin, total flavonoids and total sugar in the fractions were determined. ResultsThe n-buthanol fraction, a saponin-rich fraction obtained by partitioning the ethanol extract with n-buthanol after petroleum ether and acetic ether showed the highest anti-diabetic potential in glucose uptake in HepG2 cells followed by acetic ether fraction which was rich in flavonoids. Further fractionation the saponin-rich fraction using macroporous resin column (D101), polysaccharide, flavonoid and saponin rich fractions were obtained by elution with water, 40% and 60% ethanol, respectively and their anti-diabetic potentials proved by glucose uptake test in HepG2 cells and STZ-induced diabetic rats were in the order of saponin rich fraction>flavonoid rich fraction>polysaccharide rich fraction. Long-term therapy test (60d) in severe diabetic rats indicated that saponin-rich fraction significantly ameliorated clinical symptoms of diabetes including the elevated blood glucose, body weight loss as well as the increased food and water intake while flavonoid-rich fraction was more potential than saponin-rich fraction to increase superoxide dismutase (SOD) activity and decrease malondialdehyde (MDA) level in rat plasma. Additionally, saponin-rich fraction and flavonoid-rich fraction showed α-glycosidase inhibitory activity with IC50 value of 2.05±0.32 and 3.92±0.65mg/ml, respectively. ConclusionThe results suggested that saponin in this herb was more important than flavonoid in exhibiting anti-diabetic activity and flavonoid contributed more to anti-oxidant activity in vivo.