Hypoglycemic activity of Codonopsis pilosula (Franch.) Nannf. in vitro and in vivo and its chemical composition identification by UPLC-Triple-TOF-MS/MS.

Codonopsis pilosula (Franch.) Nannf. (CPN), mainly planted in the northwest region, is a traditional Chinese medicine/good health food for nourishing qi and promoting blood circulation. This study firstly evaluated the inhibitory effects of the CPN extraction (CPNE) on α-glucosidase in vitro and in vivo, and tentatively confirmed its chemical ingredients by employing UHPLC-Triple-TOF-MS/MS. The CPNE had strong inhibitory activities against mammalian α-glucosidase (sucrase and maltase) and yeast α-glycosidase with semi-inhibitory concentrations (IC50) of 0.241 mg mL-1, 0.326 mg mL-1 and 1.167 mg mL-1, respectively. In addition, the CPNE could significantly decrease the postprandial blood glucose (PBG) levels in the sucrose/maltose/starch tolerance assays of diabetic mice. Furthermore, a total of 29 compounds, including 3 alkaloids, 13 phenolic acids, 8 alcohol glycosides and 5 alkynosides, were assigned based on comparison with the standards and references, as well as the analysis of main fragments. These results demonstrated that CPN could be used as an adjuvant therapy or dietary supplements to effectively control the occurrence and development of diabetes.

Structure and inhibition of Cryptococcus neoformans sterylglucosidase to develop antifungal agents.

Pathogenic fungi exhibit a heavy burden on medical care and new therapies are needed. Here, we develop the fungal specific enzyme sterylglucosidase 1 (Sgl1) as a therapeutic target. Sgl1 converts the immunomodulatory glycolipid ergosterol 3ß-D-glucoside to ergosterol and glucose. Previously, we found that genetic deletion of Sgl1 in the pathogenic fungus Cryptococcus neoformans (Cn) results in ergosterol 3ß-D-glucoside accumulation, renders Cn non-pathogenic, and immunizes mice against secondary infections by wild-type Cn, even in condition of CD4+ T cell deficiency. Here, we disclose two distinct chemical classes that inhibit Sgl1 function in vitro and in Cn cells. Pharmacological inhibition of Sgl1 phenocopies a growth defect of the Cn Δsgl1 mutant and prevents dissemination of wild-type Cn to the brain in a mouse model of infection. Crystal structures of Sgl1 alone and with inhibitors explain Sgl1's substrate specificity and enable the rational design of antifungal agents targeting Sgl1.

Bioactive secondary metabolites from the deep-sea derived fungus Aspergillus sp. SCSIO 41029.

Two new compounds classified as one new lumazine peptide, penilumamide K (1) and one new sesquiterpene (2), were obtained from the deep-sea derived fungus Aspergillus sp. SCSIO 41029, together with eleven known compounds (3-13). The structures of 1-13 including absolute configurations were determined by detailed NMR spectroscopy, HR-ESI-MS, chemical derivatization, and optical rotation data. Among them, compound 1 represents the first lumazine peptide reported from deep-sea derived fungus. The bioactive assay exhibited that compounds 1, 3, 4, 5, 7 and 10 had significant potency against α-glucosidase with IC50 values ranging from 18.61 to 109.06 µΜ. In addition, compounds 4 and 9 showed strong antibacterial activity against Staphylococcus aureus with MIC values of 0.78 and 6.25 µg ml-1, respectively.

The inhibitory effect of the catechin structure on advanced glycation end product formation in alcoholic media.

Advanced glycation end products (AGEs) and their important intermediate products (α-dicarbonyl compounds) that are generated by the Maillard reaction are closely related to diabetes. Our study first investigated the mechanisms of the anti-glycation effects of epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), and (-)-epigallocatechin gallate (EGCG) in an alcoholic environment. The results showed that catechins played an important role in the inhibition of AGE formation, and the effect of EC was the best. Their corresponding mechanisms included total antioxidant capacity (TAOC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, trapping of methylglyoxal (MGO), protection of the protein structure, and inhibition of the activities of α-amylase, α-glucosidase, and ß-glucosidase, which were consistent with the study of molecular docking. This study will offer a theoretical basis for the applications of different types of catechins to alcoholic beverages as natural AGE formation inhibitors.

Glucitol-core containing gallotannins inhibit the formation of advanced glycation end-products mediated by their antioxidant potential.

Glucitol-core containing gallotannins (GCGs) are polyphenols containing galloyl groups attached to a 1,5-anhydro-d-glucitol core, which is uncommon among naturally occurring plant gallotannins. GCGs have only been isolated from maple (Acer) species, including the red maple (Acer rubrum), a medicinal plant which along with the sugar maple (Acer saccharum), are the major sources of the natural sweetener, maple syrup. GCGs are reported to show antioxidant, α-glucosidase inhibitory, and antidiabetic effects, but their antiglycating potential is unknown. Herein, the inhibitory effects of five GCGs (containing 1-4 galloyls) on the formation of advanced glycation end-products (AGEs) were evaluated by MALDI-TOF mass spectroscopy, and BSA-fructose, and G.K. peptide-ribose assays. The GCGs showed superior activities compared to the synthetic antiglycating agent, aminoguanidine (IC50 15.8-151.3 vs. >300 µM) at the early, middle, and late stages of glycation. Circular dichroism data revealed that the GCGs were able to protect the secondary structure of BSA protein from glycation. The GCGs did not inhibit AGE formation by the trapping of reactive carbonyl species, namely, methylglyoxal, but showed free radical scavenging activities in the DPPH assay. The free radical quenching properties of the GCGs were further confirmed by electron paramagnetic resonance spectroscopy using ginnalin A (contains 2 galloyls) as a representative GCG. In addition, this GCG chelated ferrous iron, an oxidative catalyst of AGE formation, supported a potential antioxidant mechanism of antiglycating activity for these polyphenols. Therefore, GCGs should be further investigated for their antidiabetic potential given their antioxidant, α-glucosidase inhibitory, and antiglycating properties.

ZnO Nanoparticles-Red Sandalwood Conjugate: A Promising Anti-Diabetic Agent.

With the advances in nanoscience and nanotechnology the interest of researchers has expanded to interdisciplinary domain like bio-medical applications. Among such domains, one of the most important areas explored meticulously is the development of promising solutions in diabetes therapeutics. The disease associated with metabolic disorder, is one of the major challenges, due to its ever-increasing number of patients. The adverse effects of the synthetic enzymes like α-amylase and α-glucosidase inhibitors have invited many scientists to develop promising contender with minimal side-effects. On the other hand, Zinc has strong role in insulin synthesis, storage and secretion and thus its deficiency can be related to diabetes. In this context we have explored natural extract of Red Sandalwood (RSW) as a potent anti-diabetic agent, in conjugation with ZnO nanoparticles. ZnO nanoparticles have been synthesized via soft chemistry routes and duly characterized for their phase formation with the help of X-ray diffraction technique and Field-Emission Scanning Electron Microscopy. These monodispersed nanoparticles, -20 nm in size, were further conjugated to RSW extract. The conjugation chemistry was studied via Fourier transform infrared spectroscopy, UV-visible spectroscopy. Extract loading percentage was found from thermo-gravimetric analysis. 65% of the RSW extract was found conjugated to the ZnO nanoparticles. The anti-diabetic activity was assessed with the help of like α-amylase and α-glucosidase inhibition assay with murine pancreatic and small intestinal extracts. It was observed that the conjugated ZnO-RSW nanoparticles showed excellent activity against the crude murine pancreatic glucosidase as compared to the individual ZnO nanoparticles and the RSW extract. The ZnO-RSW conjugate showed 61.93% of inhibition while the bare ZnO nanoparticles and RSW showed 21.48% and 5.90% respectively.

Alpha-glucosidase inhibitor proteins from Sesbania grandiflora flowers.

Two alpha-glucosidase inhibitors were isolated from the flowers of Sesbania grandiflora and named SGF60 and SGF90. The procedure involved extraction with phosphate buffer, precipitation with ammonium sulfate, ion-exchange chromatography on DEAE-cellulose and gel filtration on Superdex-200. These proteins were identified by using tandem mass spectrometry. The results show partial amino acid sequences of SGF60 similar to p27SJ, a protein from Hypericum perforatum found to suppress HIV-1 gene expression. SGF90 matched a beta-glucosidase from Arabidopsis thaliana.

Recent biochemical approaches to post-testicular, epididymal contraception.

Results from recent animal models with implications for putative human male contraceptives acting on the epididymis are reviewed. Inducing sterility by enhancing sperm transport through the epididymis has not been achieved. The induction of infertility in males of several species is easier to achieve by direct actions of drugs on sperm function (e.g. inhibition of sperm-specific isoenzymes of the glycolytic pathway by chloro-compounds) than by indirectly reducing amounts of epididymal secretions normally present in high concentration (e.g. alpha-glucosidase, L-carnitine). The former show promise for the clinic since human spermatozoa are susceptible to inhibition. On the other hand, the infertile male mice of the c-ros knock-out model demonstrate the influence of even a small region of the epididymis on fertility, so that targeting the as yet unknown epididymal factors presumably secreted in limiting amounts by this epididymal segment, is a new lead for a contraceptive. Targeting a specific sperm protein acquired in the testis, but depleted in the epididymis by toxicants that induce rapid infertility, may also lead to the discovery of new contraceptives, but these will require developing new means of organ-specific delivery of contraceptive drugs.

Interaction of estradiol, progesterone and corticosterone on uterine connective tissue degrading enzymes.

The impact of ovarian hormones and corticosterone acetate on uterine connective tissue degrading enzymes were studied in mature albino rats. Ovariectomy resulted in a significant increase in the activities of alpha- and beta-galactosidases and glucosidases in the uterus. Administration of estradiol to ovariectomized rats brought back the activities of alpha-galactosidase and alpha-glucosidase to normalcy. While beta-galactosidase and beta-glucosidase were significantly decreased. Administration of progesterone to ovariectomized rats resulted in the increase of alpha- and beta-galactosidases and glucosidases. Administration of corticosterone to ovariectomized rats produced a further increase in alpha- and beta-galactosidases and glucosidases in the uterus. Adrenalectomy in ovary intact rats produced a decrease in alpha-galactosidase however, beta-glucosidase was significantly increased. Administration of corticosterone to ovary intact rats significantly increased the activities of alpha- and beta-galactosidases, while alpha- and beta-glucosidases were found to be decreased. Ovariectomy resulted in a significant increase in the activities of cathepsin-D and cathepsin-E. Administration of estradiol to ovariectomized rats brought back the activity of cathepsin-D to normalcy, whereas cathepsin-E was significantly increased. Administration of progesterone as well as estradiol to ovariectomized rats significantly increased the levels of cathepsin-E, however, cathepsin-D was brought back to normalcy. Administration of corticosterone to ovariectomized rats as well as ovariectomy + adrenalectomy significantly increased the activity of cathepsin-D and cathepsin-E. Adrenalectomy significantly decreased the activity of cathepsin-D, while administration of corticosterone increased the cathepsin-D and cathepsin-E in the uterus. Therefore, these results suggest that estradiol is a potent ovarian steroid protecting the extra cellular matrix components. The effect of progesterone appears to modulate and act hand in hand with estradiol. Corticosterone appears to have an opposite effect to that of estradiol.

Treatment with acarbose, an alpha-glucosidase inhibitor, reduces increased albumin excretion in streptozotocin-diabetic rats.

1. We examined the effect of the alpha-glucosidase inhibitor acarbose on urinary albumin excretion (UAE) in streptozotocin diabetic rats. 2. Treatment with acarbose for 8 weeks after induction of diabetes prevented the significant increase in UAE observed in untreated diabetic rats relative to nondiabetic controls. 3. Acarbose significantly reduced integrated glycemia, which correlated with albumin excretion rates, and exerts a salutary effect on diabetic renal dysfunction.

Inhibitors of pig kidney trehalase.

Trehazolin, a new trehalase inhibitor isolated from the culture broth of Micromonospora, was reported to be a highly specific inhibitor for porcine and silk worm trehalases with IC50 values of 5.5 x 10(-9) and 3.7 x 10(-9) M, respectively (O. Ando, H. Satake, K. Itoi, A. Sato, M. Nakajima, S. Takashi, H. Haruyama, Y. Ohkuma, T. Kinoshita, and R. Enokita (1991) J. Antibiot. 44, 1165-1168). We also found that trehazolin is a very powerful and quite specific inhibitor against purified pig kidney trehalase, giving an IC50 value of 1.9 x 10(-8) M. Lineweaver-Burk plots showed that this compound was a competitive inhibitor of the trehalase. However, even at concentrations of 200 micrograms/ml, trehazolin did not inhibit the rat intestinal maltase or sucrase, yeast alpha-glucosidase or almond beta-glucosidase. Validoxylamine A and validamycin A, two other trehalase inhibitors, showed potent competitive inhibition against purified pig kidney trehalase, with IC50 values of 2.4 x 10(-9) and 2.5 x 10(-4) M, respectively. On the other hand, validoxylamine A was almost inactive against rat intestinal sucrase and maltase, with some inhibition being observed at millimolar concentration. A number of other glucosidase inhibitors, such as MDL 25637, castanospermine, and deoxynojirimycin were also tested against the purified trehalase and showed reasonable inhibitory activity.

Recovery of biologically active enzymes after HPLC separation.

The mass and activity recovery of eight different enzymes (two monomeric, six oligomeric) with molecular masses between 25,000 and 240,000 daltons were tested after HPLC separation on three different HPLC instruments (two with stainless steel and one with titanium flow paths). Most of the tested proteins are known to be sensitive to heavy metal ions. Eight wide pore, ion-exchange columns, two size-exclusion columns and two hydrophobic-interaction columns were used. Both stainless steel and glass column hardware were used in all three separation modes. The elution times were between 8 and 12 minutes. In almost all cases, the activity recovery was between 90% and 100% compared with a control sample incubated in the chromatographic elution buffer for the same time at the same temperature. A severe activity loss (about 30%) was observed with only one ion-exchange column and one enzyme. Neither the column hardware nor the material of the HPLC equipment had any negative effect on the activity recovery of the enzymes tested.