Terpenoids from Curcuma wenyujin increased glucose consumption on HepG2 cells.

Thirty four terpenoids, including two new cadinane-type sesquiterpenoids containing conjugated aromatic-ketone moieties, curcujinone A (1) and curcujinone B (2), were isolated from 95% ethanol extract of the root tubers of Curcuma wenyujin. Their structures were determined by spectroscopic methods, especially 2D NMR and HRMS techniques. The relative and absolute configurations of 1 and 2 were identified by quantum chemical DFT and TDDFT calculations of the 13C NMR chemical shifts, ECD spectra, and specific optical rotations. All compounds and extracts were evaluated for their anti-diabetic activities with a glucose consumption model on HepG2 Cells. The petroleum fraction CWP (10µg/mL) and compounds curcumenol (4), 7α,11α-epoxy-5ß-hydroxy-9-guaiaen-8-one (5), curdione (17), (1S, 4S, 5S 10S)-germacrone (18), zederone (20), a mixture of curcumanolide A (25) and curcumanolide B (26), gajutsulactone B (27), and wenyujinin C (30) showed promising activities with over 45% increasing of glucose consumption at 10µM.

Effects and molecular mechanisms of the antidiabetic fraction of Acorus calamus L. on GLP-1 expression and secretion in vivo and in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: The radix of Acorus calamus L. (AC) is widely used in diabetes therapies in traditional folk medicine from America and Indonesia, and we have previously reported that the ethyl acetate fraction of AC (ACE) acts as an antidiabetic through insulin sensitizing, insulin releasing and alpha-glucosidase inhibitory activities. The present study is designed to investigate the effects and molecular mechanisms of ACE on glucagon-like peptide-1 (GLP-1) expression and secretion related to its hypoglycemic effects. MATERIALS AND METHODS: The hypoglycemic effect of ACE (100mg/kg, i.g.) was confirmed by testing blood glucose levels or via oral glucose tolerance test (OGTT) in streptozotocin (STZ) induced hyperglycemic mice, db/db diabetic mice and diet-induced obese (DIO) mice. Plasma insulin, GLP-1 levels and intestinal GLP-1 related gene expression were determined in STZ-induced and db/db diabetic mice. The in vitro effects of ACE (12.5µg/ml) on the expression and secretion of GLP-1 were detected in NCI-H716 intestinal L-cells, and the correlation between ACE and molecules in the Wnt signaling pathway was further explored. RESULTS: ACE (100mg/kg) significantly lowered fasting blood glucose in STZ-induced and db/db diabetic mice and improved the OGTT in DIO mice. Insulin releasing and islet protective effects, along with the increased secretion of GLP-1, were observed. The expression of proglucagon gene (gcg) and post-translational processing gene prohormone convertase 3 (pc3) and the GLP-1 content in the culture medium of L-cells notably increased after the ACE treatment (12.5µg/ml). At the same time, ß-catenin nuclear translocation occurred, and its downstream protein cyclin D1 was activated, showing the involvement of Wnt signaling. CONCLUSIONS: ACE might activate Wnt signaling to increase the gene expression of gcg and pc3 and exert incretin effects, including insulinotropic and islet protection, to lower blood glucose levels via elevated GLP-1 secretion either directly or indirectly.

Insulin releasing and alpha-glucosidase inhibitory activity of ethyl acetate fraction of Acorus calamus in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: The radix of Acorus calamus L. (AC) is widely used in the therapy of diabetes in traditional folk medicine of America and Indonesia, and we previously reported the insulin sensitizing activity of the ethyl acetate fraction of AC (ACE). AIM OF THE STUDY: To investigate the insulin releasing and alpha-glucosidase inhibitory activity of ACE in vitro and in vivo. MATERIALS AND METHODS: Insulin releasing and alpha-glucosidase inhibitory effects of different fractions from AC were detected in vitro using HIT-T15 cell line and alpha-glucosidase enzyme. Furthermore, effects of ACE orally on serum glucose were detected in fasted and glucose/amylum challenged normal mice. RESULTS: AC and ACE increased insulin secretion in HIT-T15 cells as gliclazide did. As in vivo results, ACE (400 and 800 mg/kg) significantly decreased fasting serum glucose, and suppressed the increase of blood glucose levels after 2g/kg glucose loading in normal mice. In addition, ACE as a mixed-type inhibitor inhibited alpha-glucosidase activity in vitro with an IC(50) of 0.41 microg/ml, and 100mg/kg of it clearly reduced the increase of blood glucose levels after 5 g/kg amylum loading in normal mice. CONCLUSIONS: Apart from its insulin sensitizing effect, ACE may have hypoglycemic effects via mechanisms of insulin releasing and alpha-glucosidase inhibition, and thus improves postprandial hyperglycemia and cardiovascular complications.

Insulin sensitizing activity of ethyl acetate fraction of Acorus calamus L. in vitro and in vivo.

UNLABELLED: Acorus calamus L. (AC), family Araceae, have been used in the Indian and Chinese systems of medicine for hundreds of years. The radix of AC is widely used in the therapy of diabetes in traditional folk medicine of America and Indonesia. AIM OF THE STUDY: To investigate the insulin sensitizing activity and antidiabetic effects of the ethyl acetate fraction of AC (ACE). MATERIALS AND METHODS: Glucose consumption mediated by insulin was detected in L6 rat skeletal muscle cells. Diabetes and its complications related indexes were monitored after orally administrating to genetically obese diabetic C57BL/Ks db/db mice daily for 3 weeks. RESULTS: ACE (12.5 and 25 microg/ml) increased glucose consumption mediated by insulin in L6 cells (p<0.05 and p<0.01). In db/db mice, ACE (100 mg/kg) significantly reduced serum glucose, triglyceride, reinforce the decrease of total cholesterol caused by rosiglitazone (at least p<0.05), and markedly reduced free fatty acid (FFA) levels and increased adiponectin levels (p<0.01 and p<0.05) as rosiglitazone did (p<0.05 and p<0.001). Serum insulin was decreased but not significantly. In addition, ACE decreased the intake of food and water, and did not increase body weight gain whereas rosiglitazone did. CONCLUSIONS: Owing to the ability of insulin sensitizing, ACE has the potential to be useful for the treatment of diabetes and cardiovascular complications without body weight gain.

A fraction of Acorus calamus L. extract devoid of beta-asarone enhances adipocyte differentiation in 3T3-L1 cells.

The effects of fractions partitioned from the ethanol extract of Acorus calamus L. (AC) on adipocyte differentiation were investigated using cultured mouse 3T3-L1 preadipocytes. The degree of differentiation was evaluated by measuring the cellular triglycerides and protein expression of the glucose transporter GLUT4 in 3T3-L1 cells. The ethyl acetate fraction of the AC extract (ACE) was found to enhance adipocyte differentiation as did rosiglitazone. The results of further fractionation of ACE indicated that the active fraction does not consist of beta-asarone, which is a toxic component of this plant. This finding suggests that ACE has potential insulin-sensitizing activity like rosiglitazone, and may improve type 2 diabetes.

[Studies on anti-hyperglycemic effect and its mechanism of Dendrobium candidum].

OBJECTIVE: To study the anti-hyperglycemic effect and its mechanism of Dendrobium candidum (DC). METHOD: Normal mice, adrenaline-induced hyperglycemic mice, streptozotocin-induced diabetic (STZ-DM) rats were used. The mechanisms of the anti-hyperglycemic action were studied with radio-immunoassay, immunohistochemical HRP-SPA stain, etc. RESULT: DC could not obviously decrease the serum glucose concentrations and insulin levels in normal mice. It could increase serum insulin levels and decrease serum glucagons concentrations in STZ-DM rats. The results of immunohistochemical stain demonstrated that the number of islet beta cells was increased and that of islet a cells was decreased in STZ-DM rats. It could also decrease the serum glucose concentrations and increase liver glucogen contents in adrenaline-induced hyperglycemic mice. CONCLUSION: DC has obvious anti-hyperglycemic effects in adrenaline-induced hyperglycemic mice and STZ-DM rats. Its mechanisms are stimulating the secretion of insulin from beta cells and inhibiting the secretion of glucagons from a cells, and it can probably decrease the decomposition of liver glucogen and increase the synthesis of liver glucogen.