Anti-diabetic activity-guided screening of aqueous-ethanol Moringa oleifera extracts and fractions: Identification of marker compounds

Purpose: To explore the anti-diabetic effects of Moringa oleifera extracts and  fractions, and to identify their active/marker compounds.Methods: Five different aqueous ethanol extracts (95, 75, 50, 25 %v/v and 100 % water) of Moringa oleifera were given orally to normal rats to assess their hypoglycemic activities and effect on intraperitoneal glucose tolerance test (IPGTT) data. Rats with streptozotocin-induced diabetes were used to assess acute and sub-chronic anti-hyperglycemic activities. The most active extract was further subjected to liquid-liquid fractionation into hexane, chloroform, ethyl acetate,  butanol, and water; these fractions were screened for anti-diabetic activities. The most active extract, and fractions thereof, were then subjected to qualitative and quantitative phytochemical analysis. Standardization was achieved via thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC), and used to identify marker compounds.Results: Of all the extracts and fractions, 95 % (v/v) ethanol extract (at 1,000 mg/kg) and the butanol fraction thereof (at 500 mg/kg) were the most active,  reducing blood glucose concentration after onetime (acute) administration to  diabetic rats (p < 0.01). No significant hypoglycemic activity was apparent, and the materials had no effect on IPGTT performance by normal rats. TLC and HPLC  identified quercetin 3-β-D-glucoside, kaempferol-3-O-glucoside, and cryptochlorogenic acid.Conclusion: An M. oleifera leaf extract exhibited anti-hyperglycaemic activity in diabetic rats only. This effect was likely attributable to cryptochlorogenic acid, quercetin 3-β-D-glucoside, and kaempferol 3-Oglucoside. Keywords: Anti-diabetic, Moringa oleifera, Cryptochlorogenic acid, Quercetin 3-β-D-glucoside, Kaempferol 3-O-glucoside, Streptozotoci

6-Meth­oxy-1-(4-meth­oxy­phen­yl)-1,2,3,4-tetra­hydro-9H-β-carbolin-2-ium acetate

In the title compound, C19H21N2O2 +·C2H3O2 −, the 1H-indole ring system is essentially planar [maximum deviation = 0.0257 (14) Å] and forms a dihedral angle of 87.92 (7) Å with the benzene ring attached to the tetra­hydro­pyridinium fragment. The tetra­hydro­pyridinium ring adopts a half-chair conformation. In the crystal, cations and anions are linked by inter­ionic N—H⋯O, C—H⋯O and C—H⋯N hydrogen bonds into chains along the a axis

Erythromycin B: conformational analysis and antibacterial activity

Erythromycin B, an acid-stable co-metabolite of the important antibiotic erythromycin A, differs from erythromycin A only in the absence of a hydroxyl group at C12, yet it has never been licensed for clinical use. We describe an NMR-based analysis of the conformation of erythromycin B, both free in aqueous solution and when weakly bound to bacterial ribosomes and show that it is conformationally similar to erythromycin A. The antibacterial activity of erythromycin B is shown to be similar to that of erythromycin A, but after acid-treatment, resembling exposure to the stomach, erythromycin B substantially retains antibacterial activity, whereas erythromycin A does not

Flavonoids-Rich Orthosiphon stamineus Extract as New Candidate for Angiotensin I-Converting Enzyme Inhibition: A Molecular Docking Study

This study aims to evaluate the in vitro angiotensin-converting enzyme (ACE) inhibition activity of different extracts of Orthosiphon stamineus (OS) leaves and their main flavonoids, namely rosmarinic acid (RA), sinensetin (SIN), eupatorin (EUP) and 30-hydroxy-5,6,7,40-tetramethoxyflavone (TMF). Furthermore, to identify possible mechanisms of action based on structure–activity relationships and molecular docking. The in vitro ACE inhibition activity relied on determining hippuric acid (HA) formation from ACE-specific substrate (hippuryl-histidyl-leucine (HHL)) by the action of ACE enzyme. A High Performance Liquid Chromatography method combined with UV detection was developed and validated for measurement the concentration of produced HA. The chelation ability of OS extract and its reference compounds was evaluated by tetramethylmurexide reagent. Furthermore, molecular docking study was performed by LeadIT-FlexX: BioSolveIT’s LeadIT program. OS ethanolic extract (OS-E) exhibited highest inhibition and lowest IC50 value (45.77 � 1.17 �g/mL) against ACE compared to the other extracts. Among the tested reference compounds, EUP with IC50 15.35 � 4.49 �g/mL had highest inhibition against ACE and binding ability with Zn (II) (56.03% � 1.26%) compared to RA, TMF and SIN. Molecular docking studies also confirmed that flavonoids inhibit ACE via interaction with the zinc ion and this interaction is stabilized by other interactions with amino acids in the active site. In this study, we have demonstrated that changes in flavonoids active core affect their capacity to inhibit ACE. Moreover, we showed that ACE inhibition activity of flavonoids compounds is directly related to their ability to bind with zinc ion in the active site of ACE enzyme. It was also revealed that OS extract contained high amount of flavonoids other than RA, TMF, SIN and EUP. As such, application of OS extract is useful as inhibitors of ACE

Bis(6-meth­oxy-1-methyl-2,3,4,9-tetra­hydro-1H-β-carbolin-2-ium) tetra­chloridozincate(II) dihydrate

The asymmetric unit of the title compound, (C13H17N2O)2[ZnCl4]·2H2O, contains two tetra­hydro­harmine cations, one tetra­chloro­zincate(II) anion and two water mol­ecules. In the cations, the two 1H-indole ring systems are essentially planar, with maximum deviations of 0.016 (2) and 0.018 (2) Å, and both tetra­hydro­pyridinium rings show a half-chair conformation. The ZnII complex anion has a distorted tetra­hedral geometry. In the crystal, inter­molecular N—H⋯O, N—H⋯Cl, O—H⋯O, O—H⋯Cl and C—H⋯O hydrogen bonds link the components into a three-dimensional network. A π–π inter­action with a centroid–centroid distance of 3.542 (14) Å is also observed

In Vitro and in Vivo Effects of Three Different Mitragyna speciosa Korth Leaf Extracts on Phase II Drug Metabolizing Enzymes—Glutathione Transferases (GSTs)

In the present study, we investigate the effects of three different Mitragyna speciosa extracts, namely methanolic, aqueous and total alkaloid extracts, on glutathione transferase-specific activity in male Sprague Dawley rat liver cytosol in vitro and in vivo. In the in vitro study, the effect of Mitragyna speciosa extracts (0.01 to 750 µg/mL) against the specific activity of glutathione transferases was examined in rat liver cytosolic fraction from untreated rats. Our data show concentration dependent inhibition of cytosolic GSTs when Mitragyna speciosa extract was added into the reaction mixture. At the highest concentration used, the methanolic extract showed the highest GSTs specific activity inhibition (61%), followed by aqueous (50%) and total alkaloid extract (43%), respectively. In in vivo study, three different dosages; 50, 100 and 200 mg/kg for methanolic and aqueous extracts and 5, 10 and 20 mg/kg for total alkaloid extract were given orally for 14 days. An increase in GST specific activity was generally observed. However, only Mitragyna speciosa aqueous extract with a dosage of 100 mg/kg showed significant results: 129% compared to control

Synthesis and Crystal Structure Analysis of 9-Phenyl-β-carboline

<div><p>An efficient method is described for the synthesis of 9-phenyl-9H-pyrido[3,4-b]indole and 9-(4-chlorophenyl)-9H-pyrido[3,4-b]indole by employing a catalytic amount of CuI (10 mole%) without any ligand. The single crystal of 9-phenyl-9H-pyrido[3,4-b]indole was produced by crystallization from hexane and ethyl acetate mixture that was investigated by single X-ray diffraction (XRD). The compound crystallizes in monoclinic P21/c space group with unit cell dimensions a = 11.3132(5) Å, b = 12.0061(5) Å, c = 9.2498(4) Å, α = 90°, β = 103.187(3)°, γ = 90°. ¹H and ¹³C NMR, IR, and mass spectroscopic methods of the compounds are also discussed.</p></div

In Vitro Antioxidant and Xanthine Oxidase Inhibitory Activities of Methanolic Swietenia mahagoni Seed Extracts

This study examines the in vitro antioxidant activities of the methanol extract of Swietenia mahagoni seeds (SMCM seed extract). The extract was screened for possible antioxidant activities by free radical scavenging activity (DPPH), xanthine oxidase inhibition (XOI), hydrogen peroxide scavenging activity (HPSA) and ferric-reducing antioxidant power (FRAP) assays. The total phenolic and flavonoid contents were also determined. The extract exhibits antioxidant activity of 23.29% with an IC50 value of 2.3 mg/mL in the DPPH radical scavenging method, 47.2% in the XOI assay, 49.5% by the HPSA method, and 0.728 mmol/Fe(II)g in the FRAP method at the concentration tested. The amount of total phenolics and flavonoid contents was 70.83 mg gallic acid equivalent (GAE) and 2.5 ± 0.15 mg of catechin equivalent per gram of dry extract, respectively. High Performance Thin Layer Chromatography (HPTLC) screening indicates the presence of phenolic compounds in the SMCM seed extract. The results indicate that the extract has both high free radical scavenging and xanthine oxidase inhibition activity. The antioxidant activity of SMCM seed extract is comparable with that of other Malaysian tropical fruits and herbal plants