Hypoglycemic activity of Nymphaea stellata leaves ethanolic extract in alloxan induced diabetic rats

Hypoglycaemic and hypolipidemic activities of total flavonoids from Nymphaea candida flowers on diabetic mice

This study aimed to investigate the hypoglycaemic and hypolipidemic activities of total flavonoids from Nymphaea candida (NCTF). The result showed that NCTF could significantly ameliorate various indicators such as FBG, OGTT, TC, TG, LDL-C, and HDL-C in ALX-induced diabetic mice compared with the model group. Meanwhile, in the therapeutical effect study of NCTF on high-fat and high-sugar diets combined with STZ-induced T2DM mice, all parameters including RBG, INS, and INSR related to diabetes were significantly improved by NCTF as well as the serum ALT, AST, ALP, CR, MDA, and IL-6 activities. NCTF could significantly increase the expression levels of SOD and PPAR-γ in T2DM. Pathological observation showed that NCTF could improve the damage to pancreatic and liver tissues in T2DM mice. In conclusion, NCTF has better hypoglycaemic and hypolipidemic effects, and its mechanism may be related to its antioxidant, PPAR-γ regulation, and inhibiting inflammatory cytokine expression.

Pancreatic regenerative potential of manuka honey evidenced through pancreatic histology and levels of transcription factors in diabetic rat model

Background

Diabetes mellitus is a commonly occurring metabolic disorder accompanied by high morbidity and alarming mortality. Besides various available therapies, induction of pancreatic regeneration has emerged as a promising strategy for alleviating the damaging effect of diabetes. Honey, a potent antioxidative and anti-inflammatory agent, has been reported in the literature archive to exhibit favourable results in the regeneration process of several organ systems.

Design

The current research work was intended to explore the potential role of manuka honey in pancreatic regeneration in alloxan-induced diabetic rats by accessing the pancreatic histology and levels of relevant transcription factors, including MAFA, PDX-1, INS-1, INS-2, NEUROG3, NKX6-1, and NEUROD. An equal number of rats were allocated to all four experimental groups: normal, negative control, positive control, and treatment group. Diabetes was induced in all groups except normal through a single intraperitoneal dose of alloxan monohydrate. No subsequent treatment was given to the negative control group, while the positive control and treatment groups were supplemented with metformin (150 mg/kg/day) and manuka honey (3 g/kg/day), respectively.

Results

Statistical comparison of glucose and insulin levels, oxidative stress indicators, changes in the architecture of pancreatic islets, and expression levels of regeneration-associated transcription factors advocated the potential role of manuka honey in ameliorating the alloxan-induced hyperglycaemia, hyperinsulinemia, oxidative stress, and necrotic changes in islets along with significant upregulation of relevant transcription factors.

Conclusion

This suggests to us the auspicious role of antioxidants in honey in pancreatic regeneration and advocates the favourable role of manuka honey in combating diabetes mellitus.

Isolation and Characterization of Flavonoid Naringenin and Evaluation of Cytotoxic and Biological Efficacy of Water Lilly (Nymphaea mexicana Zucc.)

Despite its limited exploration, Nymphaea mexicana Zucc. can be beneficial if pharmacology, isolation, and biological evaluation are given attention. It is an aquatic species that belongs to the family Nymphaeaceae. The thrust area of the work was the extraction, isolation, and biological evaluation of different extracts of the N. mexicana Zucc. plant. The primary goal of this research was to assess the antimicrobial, antioxidant, and anticancer activities of the extracts and to isolate the target naringenin compound. Comparative FT IR analysis of different extracts of this plant revealed the presence of functional groups of plant secondary metabolites, including polyphenols, flavonoids, terpenoids, esters, amines, glycosides, alkanes, alkaloids, fatty acids, and alcohols. Moderate free radical scavenging potential has been achieved for the various extracts via reducing power and DPPH assays. While cytotoxic activity was evaluated by colorimetric and lactate dehydrogenase cell viability tests on potent cancer cell lines. Lung adenocarcinoma epithelial cells (A-549), and breast cells (MC-7) were treated with MeOH extract. The antimicrobial activity against bacterial strains was evaluated using Gram-positive and -negative cultures, where maximum and minimum inhibition zones were recorded for different strains, including 1.6-25.6 μg/mL for Streptococcus aureus, using the agar well diffusion method. In addition, the anti-inflammatory activity of different extracts of N. mexicana Zucc. was evaluated in a nitrite radical scavenging assay with high concentrations of secondary metabolites, which are important against human pathogens and other diseases.

Ethnomedicinal Value of Antidiabetic Plants in Bangladesh: A Comprehensive Review

The use of conventional drugs to treat metabolic disorders and the pathological consequences of diabetes further increases the complications because of the side effects, and is sometimes burdensome due to relatively higher costs and occasionally painful route of administration of these drugs. Therefore, shifting to herbal medicine may be more effective, economical, have fewer side effects and might have minimal toxicity. The present review amasses a list of ethnomedicinal plants of 143 species belonging to 61 families, from distinctive domestic survey literature, reported to have been used to treat diabetes by the ethnic and local people of Bangladesh. Leaves of the medicinal plants were found leading in terms of their use, followed by fruits, whole plants, roots, seeds, bark, stems, flowers, and rhizomes. This review provides starting information leading to the search for and use of indigenous botanical resources to discover bioactive compounds for novel hypoglycemic drug development.

Phenolic Content and Antioxidant, Antihyperlipidemic, and Antidiabetogenic Effects of Opuntia dillenii Seed Oil

Opuntia dillenii (Ker-Gawl.) Haw. is a medicinal plant that is widely used by the Moroccan population to treat many diseases, thanks to its richness in bioactive molecules. This study aims to evaluate the total phenolic content and antioxidant, antihyperlipidemic, and antidiabetogenic activities of O. dillenii seeds oil (ODSO), in vivo. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay and the Folin–Ciocalteu method were applied in this study to determine antioxidant activity and total phenolic content of ODSO, respectively. The antihyperlipidemic effect of the ODSO (2 ml/kg) was evaluated in the high-fat diet-fed albino mice, relying on lipid profile, blood glucose, and growth performance variations. Moreover, the preventive effect of ODSO was evaluated against alloxan monohydrate-induced diabetes in albino mice. ODSO had the highest total phenolic content (518.18 ± 14.36 mg EAC/kg) and DPPH scavenging activity (IC₅₀ = 0.38 ± 0.08 mg/mL). Furthermore, ODSO showed a significant antidiabetogenic effect by reducing bodyweight loss, blood sugar level rise, and mortality rate caused by alloxan in albino mice. Then, ODSO has exhibited a significant antihyperlipidemic effect by improving the lipid profile disorder and glucose level rise in the blood, produced by the high-fat diet-fed albino mice. Results suggest that antidiabetogenic and antihyperlipidemic activities of ODSO correlate to the phenolic content and antioxidant activity of this oil. Hence, this plant could be a significant source of medically important critical compounds.

Antidiabetic and antiplatelet aggregation study of various methanol fractions of Nymphaea stellata Willd. leaves

Introduction: Nymphaea stellata Willd. (Nymphaeaceae) is traditionally used for the treatment of diabetes. Alcohol extract of N. stellata leaves has been reported for hypoglycaemic activity. Objective: The aim of this study was to further investigate the different methanol fractions of N. stellata leaves for anti-diabetic activity and anti-platelet aggregation activity. Methods: Methanol extract was fractioned in to unsaponified petroleum ether fraction of methanol extract (UPFME), chloroform fraction of methanol extract (CFME) and residual fraction of methanol extract (RFME). All fractions were evaluated for in vivo anti-diabetic activity (STZ-NAD-induced rat model), in vitro anti-diabetic activity (PTP1B inhibition study) and anti-platelet aggregation activity. Results: UPFME showed significant changes in all studied parameters, compared to the diabetic control. UPFME also showed an IC50 value of 19.30±1.1 mg/ml and 13.11±0.7 μg/ml in PTP1B inhibition study and anti-platelet aggregation study, respectively. Conclusion: The study indicates that UPFME of N. stellata leaves exhibit anti-diabetic and anti-platelet aggregation activity.

Transcriptome sequencing and metabolite analysis for revealing the blue flower formation in waterlily

Background

Waterlily (Nymphaea spp.), a perennial herbaceous aquatic plant, is divided into two ecological groups: hardy waterlily and tropical waterlily. Although the hardy waterlily has no attractive blue flower cultivar, its adaptability is stronger than tropical waterlily because it can survive a cold winter. Thus, breeding hardy waterlily with real blue flowers has become an important target for breeders. Molecular breeding may be a useful way. However, molecular studies on waterlily are limited due to the lack of sequence data.

Results

In this study, six cDNA libraries generated from the petals of two different coloring stages of blue tropical waterlily cultivar Nymphaea ‘King of Siam’ were sequenced using the Illumina HiSeq™ 2500 platform. Each library produced no less than 5.65 Gb clean reads. Subsequently, de novo assembly generated 112,485 unigenes, including 26,206 unigenes annotated to seven public protein databases. Then, 127 unigenes could be identified as putative homologues of color-related genes in other species, including 28 up-regulated and 5 down-regulated unigenes. In petals, 16 flavonoids (4 anthocyanins and 12 flavonols) were detected in different contents during the color development due to the different expression levels of color-related genes, and four flavonols were detected in waterlily for the first time. Furthermore, UA3GTs were selected as the most important candidates involved in the flavonoid metabolic pathway, UA3GTs induced blue petal color formation in Nymphaea ‘King of Siam’.

Conclusions

This study will improve our understanding of the molecular mechanism of blue flowers in waterlily and provide the basis for molecular breeding of blue hardy waterlily cultivars.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-3226-9) contains supplementary material, which is available to authorized users.

In vitro and in vivo anti-diabetic and hepatoprotective effects of edible pods of Parkia roxburghii and quantification of the active constituent by HPLC-PDA

ETHNOPHARMACOLOGICAL RELEVANCE

Parkia roxburghii G. Don. is a traditional medicinal plant and its pods are extensively used as food and medicine. It is believed by the traditional healers to have medicinal properties to treat diabetes, hypertension and urinary tract infections (Jamaluddin et al., 1994).

MATERIALS AND METHODS

The methanolic extract of pods of P roxburghii and fractions were screened for their α-glucosidase and α-amylase inhibitory activity. Anti-hyperglycemic effects were studied on streptozotocin (45mg/kg b.w.) induced diabetes in albino rats (seven groups, n=7 n=6), using different doses for 14 days. Plasma glucose concentration (HbA1c) was analysed using whole blood, while SGOT, SGPT, TG, TC and uric acid were analysed using serum, employing commercial kits. Quantitative analysis of the major active constituent was carried out by HPLC-PDA.

RESULTS

Bioactivity guided chemical investigation of the edible pods of P roxburghii identified sub-fraction EA-Fr 5 which significantly inhibited α-glucosidase (IC50 0.39±0.06 µgmL(-1)), reduced the blood glucose level to normal, and lowered the elevated levels of liver function enzymes SGOT and SGPT in STZ-induced diabetic rats. EA-Fr 5 was found to contain epigallocatechin gallate (1) and hyperin (2) which exhibited significantly higher α-glucosidase inhibitory potency with IC50 0.51±0.09 and 0.71±0.03µM respectively. EA-Fr 5 contained 379.82±2.90mg/g of EGCG, the major active constituent which manifests a broad spectrum of biological activities.

CONCLUSION

The present investigation for the first time reports the occurrence of EGCG and hyperin in P roxburghii and substantiates the traditional use of pods of P roxburghii as dietary supplement for management of diabetes with significantly promising α-glucosidase inhibitory potency and anti-hyperglycemic as well as hepatoprotective effects.

Plant-Derived Compounds Targeting Pancreatic Beta Cells for the Treatment of Diabetes

Diabetes is a global health problem and a national economic burden. Although several antidiabetic drugs are available, the need for novel therapeutic agents with improved efficacy and few side effects remains. Drugs derived from natural compounds are more attractive than synthetic drugs because of their diversity and minimal side effects. This review summarizes the most relevant effects of various plant-derived natural compounds on the functionality of pancreatic beta cells. Published data suggest that natural compounds directly enhance insulin secretion, prevent pancreatic beta cell apoptosis, and modulate pancreatic beta cell differentiation and proliferation. It is essential to continuously investigate natural compounds as sources of novel pharmaceuticals. Therefore, more studies into these compounds' mechanisms of action are warranted for their development as potential anti-diabetics.

Antioxidant plants and diabetes mellitus

The incidence of diabetes mellitus (DM) is increasing rapidly and it is expected to increase by 2030. Other than currently available therapeutic options, there are a lot of herbal medicines, which have been recommended for its treatment. Herbal medicines have long been used for the treatment of DM because of the advantage usually having no or less side-effects. Most of these plants have antioxidant activities and hence, prevent or treat hard curable diseases, other than having the property of combating the toxicity of toxic or other drugs. In this review other than presenting new findings of DM, the plants, which are used and have been evaluated scientifically for the treatment of DM are introduced.

Antidiabetic, antilipidemic, and antioxidant activities of Gouania longipetala methanol leaf extract in alloxan-induced diabetic rats

CONTEXT

Gouania longipetala Hemsl. (Rhamnaceae) is used in folkloric medicine for treating diabetes mellitus and its associated symptoms.

OBJECTIVE

This study evaluated the antidiabetic antilipidemic and antioxidant activities of the plant methanol leaf extract.

MATERIALS AND METHODS

Diabetes was induced in rats by intraperitoneal injection of alloxan monohydrate (160 mg/kg). Three test doses (50, 100, and 150 mg/kg) of G. longipetala extract (GLE) were administered orally and the effects were compared with glibenclamide (2 mg/kg). The effect of GLE on hyperglycemia and sub-acute study for 21 d were carried out using its effect on fasting blood sugar (FBS) level. Serum biochemistry and antioxidant activity were evaluated. Histopathological evaluation of the pancreas was also done.

RESULTS

The LD50 of G. longipetala was found to be >4000 mg/kg. The extract significantly (p < 0.0001) decreased the FBS levels of treated rats from 16.2 ± 2.03 to 6.5 ± 1.52 mM/L at 150 mg/kg within 24 h. The extract decreased FBS levels of rats by 62.0, 74.8, and 75.0% on day 21 at 50, 100, and 150 mg/kg, respectively. GLE reduced the level of malondiadehyde from 23.0 ± 1.34 to 10.3 ± 0.43 mg/dL, increased superoxide dismutase activities from 2.97 ± 0.34 to 5.80 ± 0.53 IU/L at 150 mg/kg, and improved the serum lipid profile of treated rats. GLE also caused restoration of the altered histopathological changes of the pancreas.

DISCUSSION AND CONCLUSION

Gouania longipetala demonstrated significant antidiabetic, antilipidemic, and antioxidant activities that may be due to its multiple effects involving both pancreatic and extra-pancreatic mechanisms.

Anti-inflammatory effects of phenolic compounds isolated from the flowers of Nymphaea mexicana Zucc

Nymphaea mexicana Zucc. is an aquatic plant species which belongs to the family Nymphaea and is commonly known as the yellow water lily. The aim of this work was to study the in vitro antiinflammatory effects of phenolic compounds isolated from the flowers of Nymphaea mexicana Zucc. Seven phenolic compounds including vanillic acid, 4-methoxy-3,5-dihydroxybenzoic acid, (2R,3R)-3,7-dihydroxyflavanone, naringenin (4), kaempferol 3-O-(3-O-acetyl-a-L-rhamnopyranoside), kaempferol 3-O-(2-O-acetyl-a-L-rhamnopyranoside), and quercetin 3-(30 0-acetylrhamnoside) (7) were isolated from the flowers of Nymphaea mexicana Zucc. These results revealed that compound 4 has the most prominent inhibitory effect on the LPS-stimulated nitric oxide (NO), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-a) production in RAW 264.7 macrophages. In addition, compound 4 also inhibited LPS-mediated induction of protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and phospho-ERK in RAW 264.7 macrophages. Thus, compound 4 from the flowers of Nymphaea mexicana Zucc. may provide a potential therapeutic approach for inflammation-associated disorders.

Histological changes and antidiabetic activities of Icacina trichantha tuber extract in beta-cells of alloxan induced diabetic rats

OBJECTIVE

To investigate the antidiabetic, hypolipidaemic activities and histopathological changes of Icacina trichantha (I. trichantha) tuber extract in alloxan induced diabetic rats.

METHODS

In the present study, 80% methanol extract of I. trichantha tuber was tested on alloxan induced diabetic rats. They were randomly grouped into control (distilled water and glibenclamide) and experimental (200, 400 and 600 mg/kg body weight). Diabetes was induced by a single intraperitoneal injection of 160 mg/kg body weight of alloxan. Blood glucose levels were measured using blood glucose test strips with AccuCheck Advantage II glucometer at 1, 3, 6, and 24 h on the first day and 1 h after treatment on Day 7, 14 and 21. Blood samples were collected and centrifuged to separate serum for estimation of lipid profile and other biochemical parameters. Histopathological changes in diabetic rats pancreas were also studied after extract treatment.

RESULTS

Daily oral administration of I. trichantha tuber extract (200, 400, and 600 mg/kg body weight) and glibenclamide (2 mg/kg) showed beneficial effects on blood glucose level (P<0.01) as well as improving liver, kidney functions and hyperlipidaemia due to diabetes. The extract had a favourable effect on the histopathological changes of the pancreas in alloxan induced diabetes.

CONCLUSIONS

I. trichantha tuber extracts posses antidiabetic activities as well as improve liver and renal profile and total lipids levels. I. trichantha tuber extracts also have favourable effects to inhibit the histopathological changes of the pancreas in alloxan induced diabetes.

A comprehensive review on Nymphaea stellata: A traditionally used bitter

Nymphaea stellata Willd. (Syn. Nymphaea nouchali Burman f.) (Nymphaeaceae) is an important and well-known medicinal plant, widely used in the Ayurveda and Siddha systems of medicines for the treatment of diabetes, inflammation, liver disorders, urinary disorders, menorrhagia, blenorrhagia, menstruation problem, as an aphrodisiac, and as a bitter tonic. There seems to be an agreement between the traditional use and experimental observations, such as, hepatoprotective, anti-inflammatory, and particularly antidiabetic activity. Nymphayol, a steroid isolated from the flowers has been scientifically proved to be responsible for the traditionally claimed antidiabetic activity; it reverses the damaged endocrine tissue and stimulates secretion of insulin in the β-cells. However, taking into account the magnitude of its traditional uses, the studies conducted are still negligible. This review is an attempt to provide the pharmaceutical prospective of Nymphaea stellata.

Hypoglycemic activity of Cassia javanica Linn. in normal and streptozotocin-induced diabetic rats

In present work, one of the ornamentals and medicinally less known plant Cassia javanica has been explored for hypoglycemic potential. It aimed to check the hypoglycemic effect of C. javanica leaves on normal and streptozotocin (STZ)-induced diabetic rats by acute and sub-acute studies. Prior to the hypoglycemic study, acute oral toxicity testing of drug was performed. Later, the effects of single and multiple doses of test drug were studied using various parameters. Dried powdered leaf material was used as an oral drug. The preliminary phytochemistry of drug was done by standard qualitative tests. Diabetes was induced in rats by single intraperitoneal injection of STZ. Single and multiple doses of test drug (0.5 g/kg body weight/day) were given to normal and diabetic rats. The parameters studied were blood glucose, serum cholesterol, serum triglycerides, and serum proteins. The results of test drug were compared with standard hypoglycemic drug-glibenclamide (0.01 g/kg/day). Statistical analysis was done by ‘Student's ‘t’ test’ and one way ANOVA test. In preliminary phytochemistry, antidiabetic compounds were detected. Unlike acute, subacute treatment of test drug showed highly significant reduction (37.62%) in blood glucose level of diabetic rats in ten days. This effect was considerably good in comparison with standard drug (63.51%). The test drug and standard drug exhibited insignificant change in the abnormal levels of serum metabolites of diabetic rats. Preclinically, C. javanica was proved to be effective hypoglycemic agent.

Preliminary study of antidiabetic activity of the methanolic leaf extract of Axonopus compressus (P. Beauv) in alloxan-induced diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Axonopus Compressus is commonly used by the people of Southern Nigeria to treat different ailment such as common cold and diabetes. This study therefore, evaluated the anti-diabetic effect of the methanolic leaf extract of the plant.

MATERIALS AND METHODS

Diabetes was induced in the rats by intraperitoneal (i.p.) injection of alloxan monohydrate at the dose of 180 mg/kg. Three test doses of the extract (250, 500 and 1000 mg/kg) administered per os through gastric gavage to the rats were used in the study. The activity was compared to a standard reference drug (glibenclamide, 2mg/kg) and a negative control. Blood from the tail snip was used to measure the effects of the extract and drug at 0, 1, 3 and 6 h using autoanalyzer (AccuCheck Active(®)) glucose kit.

RESULTS

Methanolic leaf extract of Axonopus compressus at all the doses (250, 500 and 1000 mg/kg) used caused a respective time dependent and significant (p<0.0001) reduction (by 31.5%, 19.8% and 24.5%) of the blood glucose levels in the diabetic rats when compared to the negative control group at the 6th hour. However, the reference drug (glibenclamide, 2 mg/kg) decreased the blood glucose levels by 69.9% and the tween 20 solution (negative control) increased the blood glucose level by 15.2% at the 6th hour. Moreso, the extract at the different test doses caused various degrees of reduction of the blood glucose levels of the test rats at 1st, 3rd and 6th hours when compared to the negative control rats.

CONCLUSION

The findings suggest that Axonopus compressus may possess antidiabetic property.

Intestinal alpha-glucosidase inhibitory activity and toxicological evaluation of Nymphaea stellata flowers extract

AIM OF THE STUDY

Nymphaea stellata willd. flowers (NSF) are used as a traditional medicine in India and Nepal to treat diabetic disease. Different works have demonstrated that NSF extract showed antihyperglycemic effect on alloxan-induced diabetic rats. In the present work we evaluated in vitro intestinal alpha-glucosidase inhibition as the possible mode of action of NSF extract on suppressing postprandial hyperglycemia for curing diabetic mellitus. In addition, NSF extract was studied to assess its possible acute oral toxicity and genotoxicity.

MATERIALS AND METHODS

Rat intestinal crude enzyme preparation and Caco-2 monolayer were used to evaluate alpha-glucosidase inhibitory activity of NSF extract. The main alpha-glucosidase inhibitors were detected by HPLC. For acute toxicity test, NSF extract was administered at doses of 2000, 5000 and 10,000 mg/kg body to three groups of 10 ICR mice each, and then clinical symptoms including mortality, clinical sign and gross findings were observed once a day for 14 days. In Ames test, histidine-dependent auxotrophic mutants of Salmonella typhimurium (strains TA97, TA98, TA100, TA102 and TA1535) were used and incubated in the presence and absence of S9 metabolic activation using NSF extract with concentrations of 150-5000 microg/plate. The chromosome aberration test was conducted with Chinese hamster lung (CHL) cells treated with NSF extract at doses of 150-5000 microg/ml in the presence and absence of S9 metabolic activation. In the in vivo mouse micronucleus assay, 9-week-old male and female ICR mice (n=90, 25-30 g) were administered daily by oral gavage at doses of 2.5, 5.0 and 10.0 g/kg body for 1 or 2 days. Bone marrow smears were prepared from each treatment group 24h after last administration and then polychromatic erythrocytes (PCEs) and normochromatic erythrocytes (NCEs) were identified.

RESULTS

NSF extract showed potent rat intestinal alpha-glucosidase inhibitory activity for maltose hydrolysis with ED(50) value of 0.1 mg/ml. In Caco-2 monolayer, alpha-glucosidase activity for the maltose hydrolysis was down-regulated by NSF extract at a concentration of 0.05 mg/well level, showing 74% inhibition compared to the saline treated control. NSF was rich in phenol contents and the main alpha-glucosidase inhibitor, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, was identified together with two phenolic compounds of gallic acid and corilagin. In acute toxicity test, NSF extract did not produce any toxic signs or deaths and the LD(50) value of this extract could be greater than 10,000 mg/kg body weight. These results of genotoxicity assessment showed that NSF extract did not cause genotoxic effects in Ames test, in the in vitro chromosomal aberration assay and in the in vivo micronucleus assay.

CONCLUSION

The current study shows that the extract from Nymphaea stellata flowers exhibits significant intestinal alpha-glucosidase inhibitory activity, without showing any acute toxicity or genotoxicity, which may be useful in suppressing postprandial hyperglycemia in diabetics. The results presented here suggest that the use of NSF in folk medicine as a natural antidiabetic treatment could be safe as well as beneficial.

Phytochemical characteristics and hypoglycaemic activity of fraction from mushroom Inonotus obliquus

BACKGROUND

Inonotus obliquus is a medicinal mushroom that has been used as an effective agent to treat various diseases such as diabetes, tuberculosis and cancer. In order to elucidate the active fraction and its constituents, the effects of ethyl acetate fraction from I. obliquus (EAFI) on hyperglycaemia were investigated and the main constituents of EAFI were isolated and identified.

RESULTS

EAFI treatment led to a significant decrease in blood glucose level (P < 0.05) in alloxan-induced diabetic mice. It significantly decreased the total cholesterol level in serum, increased glutathione peroxidase activity and improved the growth physiological characteristics. In addition, EAFI treatment decreased the levels of triglyceride and malondialdehyde and increased the high-density lipoprotein cholesterol level in serum and the hepatic glycogen level in liver of diabetic mice. Five compounds were isolated from EAFI and identified as lanosterol (1), 3beta-hydroxy-lanosta-8,24-diene-21-al (2), inotodiol (3), ergosterol peroxide (4) and trametenolic acid (5) by spectral methods. Inotodiol and trametenolic acid were found to have an inhibitory effect on alpha-amylase activity and a scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radicals.

CONCLUSION

EAFI showed significant antihyperglycaemic and antilipidperoxidative effects in alloxan-induced diabetic mice. Terpenoid and sterol compounds appeared to be the major active constituents of I. obliquus.