In vitro model using cytokine cocktail to evaluate apoptosis in Min6 pancreatic beta cells.

INTRODUCTION: Development of therapy options for treatment of type 1 diabetes mellitus is hampered by non-availability of appropriate experimental models that can exactly mimic the in vivo situation. Apoptosis of beta cells by T cells and cytokine action leads to loss of beta cells. We propose a simple and elegant model using cytokine cocktail of TNF-α, IFN-γ and IL-1ß, the major cytokines responsible for apoptosis in Min6 beta cell line. METHODS: A cocktail of TNF-α, IFN-γ and IL-1ß was used to induce apoptosis in Min6 beta cell line. Apoptosis was assessed by flow cytometry using CytoFLEX (Beckman Coulter). The destruction of beta cells is through production of nitric oxide (NO), oxidative stress and change in mitochondrial membrane permeability. NO was measured using Griess reagent. Oxidative stress was assessed using 2',7'-dichlorofluorescein diacetate, a cell-permeable fluorogenic dye and mitochondrial membrane potential was determined on the basis of retention of rhodamine 123 using flow cytometer. RESULTS AND DISCUSSION: Very low concentration of the cocktail viz. TNF-α 25 ng/ml, IFN-γ 25 ng/ml and IL-1ß 50 ng/ml has demonstrated effective early and late apoptosis in as short a time period as 6 h. The experimental model used demonstrated 1.5 fold higher production of NO, 1.2 fold increased oxidative stress and lower mitochondrial membrane potential as compared to the positive control used. Hence the above model can be easily used for assessment and screening of drugs that can prevent apoptosis of beta cells and stop progression of type 1 diabetes.

Biofilm inhibition mechanism from extract of Hymenocallis littoralis leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: Hymenocallis littoralis (Jacq.) Salisb. has been referred as beach spider lily and commonly known for its rich phytochemical diversity. Phytochemicals such as alkaloids, volatile constituents, phenols, flavonoids, flavonols extracted from different parts of these plants like bulbs, flowers, leaf, stem and root had been used in folk medicines from ancient times because of their excellent antimicrobial and antioxidant properties. The leaf and bulb extract of H. littoralis plant was traditionally used for wound healing. Alkaloids extracted from bulb of this plant possess anti-viral, anti-neoplastic and cytotoxic properties. However, these phytochemicals have also shown antibiofilm activity, which is considered as one of the important factor accountable for the drug resistance in microorganisms. Thus, the investigation of medicinal properties of H. littoralis could be useful to control biofilm producing pathogens. AIM OF THE STUDY: Explore antimicrobial, antibiofilm and antioxidant potentials of H. littoralis against pathogenic microorganisms using experimental and computational biology approach. MATERIALS AND METHODS: Phytochemical extraction from dried powder of H. littoralis leaves was done by solvent extraction using methanol. Antimicrobial and antibiofilm activities of leaves extract were carried out using agar well diffusion method, growth curve, minimum inhibitory concentration (MIC) and Scanning Electron Microscopy (SEM). Liquid Chromatography and Mass Spectroscopy (LCMS) technique was used for the identification of phytochemicals. Molecular docking studies of antibiofilm agents with adhesin proteins were performed using Autodock 4.2. Antioxidant activity of extract was carried out by FRAP assay. The noxious effect of extract was investigated by histological studies on rat skin. RESULTS: The preliminary phytochemical analysis of methanolic leaves extract revealed the presence of alkaloids, flavonoids, terpenoid, glycosides, terpene, terpenoids and phenolics. The various phytochemicals such as Apigenin 7-(4'', 6'' diacetylalloside)-4'- alloside, Catechin 7-O- apiofuranoside, Emodic acid, Epicatechin 3-O- ß-D-glucopyranoside, 4 - Methylesculetin, Methylisoeugenol, Quercetin 5,7,3',4'-tetramethyl ether 3-rutinoside, 4 - Methylumbelliferyl ß-D- glucuronide were extracted, characterized and recognized from the leaves extract of H. littoralis. The identification of these phytochemicals was performed using LC-MS. The antimicrobial property of H. littoralis leaf extract was investigated against different pathogenic microorganisms. Out of these tested microorganisms, promising antibiofilm and antimicrobial activities were confirmed against S. aureus NCIM 2654 and C. albicans NCIM 3466 by using growth curve and SEM analysis. MIC of this leaf extract was identified as 45 µg/ml and 70 µg/ml for S. aureus NCIM 2654 and C. albicans NCIM 3466 respectively. The leaves extract also showed good antioxidant activity due to presence of phenols and flavonoids. Molecular docking of these identified antibiofilm components interacts with the active site residues of adhesin proteins, Sortase A and Als3 from S. aureus and C. albicans respectively. Histological studies of extracted phytochemicals revealed non-noxious effects on rat skin. CONCLUSION: Thus, the present study revealed that the leaves extract of H. littoralis contains various phytochemicals having good extent of antimicrobial, antibiofilm and antioxidant properties. The in-vitro and in-silico results would be useful to design new lead compounds against biofilm producing pathogenic microorganisms.

Antidiabetic activity of Kalanchoe pinnata in streptozotocin-induced diabetic rats by glucose independent insulin secretagogue action.

CONTEXT: Kalanchoe pinnata Lam. (Crassulaceae) is used as a traditional medicine worldwide to treat several ailments, including diabetes. However, the mechanism for the antihyperglycemic action is unknown. OBJECTIVE: The present study evaluates the antihyperglycemic and insulin secretagogue potential of Kalanchoe pinnata and assessment of the probable mechanism of action. MATERIALS AND METHODS: Steam distillate of Kalanchoe pinnata leaves was subjected to solvent fractionation and antidiabetic activity was detected in dichloromethane (DCM) fraction. In the in vivo studies, rats were treated with 5 and 10 mg/kg body weight of DCM fraction for 45 days orally. Lipid profile and other biochemical parameters were estimated. The probable mechanism for insulin secretagogue action was evaluated through studies using diazoxide and nifedipine. The bioactive component from DCM fraction was studied using HPTLC, GCMS and IR. RESULTS AND DISCUSSION: Fasting blood glucose values were reduced to 116 mg/dl from 228 mg/dl on treatment with 10 mg/kg body weight of DCM fraction, while glycated hemoglobin improved to 8.4% compared with 12.9% in diabetic controls. The insulin level and lipid profile values were close to normal values. In vitro studies demonstrated a dose-dependent insulin secretagogue action. Insulin secretion was 3.29-fold higher at 10 µg/ml as compared to the positive control. The insulin secretagogue activity was glucose independent and K(+)-ATP channel dependent. The bioactive component of the DCM fraction was identified to be a phenyl alkyl ether derivative. CONCLUSION: The DCM fraction of Kalanchoe pinnata demonstrates excellent insulin secretagogue action and can be useful in treatment of diabetes mellitus.

Aegle marmelos Correa leaf extract prevents secondary complications in streptozotocin-induced diabetic rats and demonstration of limonene as a potent antiglycating agent.

OBJECTIVES: To study the antiglycating, antidiabetic and antioxidant properties of Aegle marmelos Correa leaf extract and identify the bioactive constituent. METHODS: The effect of the chloroform extract of Aegle marmelos Correa was studied in streptozotocin-induced diabetic rats through evaluation of biochemical parameters. Antiglycation activity was assessed in vitro through measurement of total and specific advanced glycation end products, protein carbonyl formation and collagen solubility tests. Antioxidant potential was evaluated using the ferric-reducing antioxidant power assay and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assays. Identification of the bioactive component was attempted through silica gel column chromatography and GC-MS analysis. RESULTS: In-vivo studies for 60 days revealed that the extract prevented kidney damage and other secondary complications. The chloroform extract at 16 µg could inhibit protein glycation by 44.33% and pentosidine formation by 59.31%, and could effectively inhibit protein carbonyl formation. It could scavenge DPPH radicals up to 85.26% (IC50: 26 µg). Bio-guided fractionation revealed limonene as the bioactive component, which could account for the antiglycating activity shown by the chloroform extract. CONCLUSION: The chloroform extract of Aegle marmelos demonstrated antidiabetic antiglycating and antioxidant activity, effectively preventing kidney damage and establishment of cataracts. Limonene is reported for the first time as possessing potent antiglycating activity and is non-toxic at the concentration used.

Insulinotropic and ß-cell protective action of cuminaldehyde, cuminol and an inhibitor isolated from Cuminum cyminum in streptozotocin-induced diabetic rats.

Cuminum cyminum, a commonly used spice, is known to have anti-diabetic action. The present study aims towards the isolation of bioactive components from C. cyminum and the evaluation of their insulin secretagogue potential with the probable mechanism and ß-cell protective action. The anti-diabetic activity was detected in the petroleum ether (pet ether) fraction of the C. cyminum distillate and studied through in vivo and in vitro experiments. Bioactive components were identified through GC-MS, Fourier transform infrared spectroscopy and NMR analysis. The isolated components were evaluated for their insulin secretagogue action using rat pancreatic islets. Further, the probable mechanism of stimulation of islets was evaluated through in vitro studies using diazoxide, nifedipine and 3-isobutyl-1-methylxanthine. ß-Cell protection was evaluated using the (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan) (MTT) assay, the alkaline comet assay and nitrite production. The administration of the pet ether fraction for 45 d to streptozotocin-induced diabetic rats revealed an improved lipid profile. Cuminaldehyde and cuminol were identified as potent insulinotrophic components. Cuminaldehyde and cuminol (25 µg/ml) showed 3·34- and 3·85-fold increased insulin secretion, respectively, than the 11·8 mm-glucose control. The insulinotrophic action of both components was glucose-dependent and due to the closure of the ATP-sensitive K (K⁺-ATP) channel and the increase in intracellular Ca²âº concentration. An inhibitor of insulin secretion with potent ß-cell protective action was also isolated from the same pet ether fraction. In conclusion, C. cyminum was able to lower blood glucose without causing hypoglycaemia or ß-cell burn out. Hence, the commonly used spice, C. cyminum, has the potential to be used as a novel insulinotrophic therapy for prolonged treatment of diabetes.

Antihyperglycemic and antihyperlipidemic effect of Santalum album in streptozotocin induced diabetic rats.

CONTEXT: Santalum album Linn (Santalaceae), commonly known as Sandalwood is used traditionally for its antihyperlipidemic and diuretic activity. OBJECTIVE: This study investigated the antihyperglycemic and antihyperlipidemic effect of long-term oral administration of the Santalum album pet ether fraction in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced by a single intraperitoneal injection of streptozotocin at 70 mg/kg body weight. Rats were treated with Santalum album pet ether fraction orally at a dose of 10 µg/kg body weight twice daily for 60 days. Metformin (30 mg/kg body weight) was used as positive control. Lipid profile and glycated hemoglobin were estimated. HPLC profiling of Santalum album pet ether fraction was carried out. RESULTS AND DISCUSSION: Treatment of diabetic rats for 60 days demonstrated reduction in blood glucose level by 140 mg/dl. Metformin treated group showed a decrease in blood glucose by 70 mg/dl, as against an increase in diabetic control group by 125 mg/dl. Total cholesterol (TC), low density lipoprotein (LDL) and triglyceride (TG) levels were decreased by 22, 31 and 44%, respectively, in treated diabetic rats whereas, cardioprotective, high density lipoprotein (HDL) increased by 46%. In case of metformin, the values were 11, 29 and 15% respectively, while HDL increased by 7%. Significant improvement in atherogenic index from 267 to 139% was observed in treated rats. CONCLUSION: Santalum album pet ether fraction has potential antihyperlipidemic activity that can help in overcoming insulin resistance.

Improvement of ethanol production using Saccharomyces cerevisiae by enhancement of biomass and nutrient supplementation.

Optimization of ethanol production through addition of substratum and protein-lipid additives was studied. Oilseed meal extract was used as protein lipid supplement, while rice husk was used as substratum. The effect of oil seed meal extract and rice husk was observed at varying concentration of medium sugar from 8% to 20%. Of the three oil seed meal extracts used, viz. groundnut, safflower, and sunflower, safflower was found to be most efficient. The use of oilseed meal extract at 4% was found to enhance ethanol production by almost 50% and enhanced sugar tolerance from 8% to 16%. A further increase of almost 48% ethanol was observed on addition of 2 g of rice husk per 100 ml of medium. An increase in cell mass with better sugar attenuation was observed. Further optimization was sought through use of sugarcane juice as the sugar source. While 8.9% ethanol yield with 75% sugar attenuation was observed at 20% sucrose concentration, it was found to increase to 12% (v/v) with almost complete utilization of medium sugar when sugarcane juice was used. Cell weight was also observed to increase by 26%.

Alpha glucosidase inhibition by stem extract of Tinospora cordifolia.

Inhibitors of alpha glucosidase have potential use in the treatment of diabetes mellitus. The stem extract of Tinospora cordifolia was evaluated for inhibition of the enzyme. The extract was also found to inhibit the salivary and pancreatic amylase and therefore can effectively reduce an increase in postprandial glucose level. The crude ethyl acetate, dichloromethane (DCM), chloroform and hexane extracts of Tinospora cordifolia were studied. 15 mg of the DCM extract was most effective in that showed 100 % inhibition of the alpha glucosidase whereas salivary amylase was inhibited to the extent of 75 % and pancreatic amylase to 83 %. On giving a maltose load of 2mg / g along with 0.3 mg / g body weight of the DCM Tinospora stem extract a decrease was revealed in the hyperglycemic shoot up in normal and diabetic animals by 50 and 58 % respectively as compared to the controls. The extract was found to inhibit alpha glucosidase in a non-competitive manner.