Volume 7 Number 1 2013

CONTENTS AND ABSTRACTS

Harshavardhan Reddy Arva, Jamuna J. Bhaskar, Paramahans V. Salimath, Aradhya Somaradhya Mallikarjuna (India) Anti-diabetic Effect of Elephant-foot Yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) in Streptozotocin-induced Diabetic Rats (pp 1-6)

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Original Research Paper: In the present study, the effect of the acetone extract of elephant-foot yam(Amorphophallus paeoniifolius (Dennst.) Nicolson) at 0.1 and 0.25% in the diet of streptozotocin-induced male Wistar diabetic rats was studied. The study involved a comparison between control and diabetic groups: starch-fed control/diabetic (SFC/SFD), 0.1% acetone extract fed control/diabetic (AEFC_0.1/AEFD_0.1), 0.25% acetone extract fed control/diabetic (AEFC_0.25/AEFD_0.25) and aminoguanidine fed control/diabetic (AFC/AFD). The rats were examined for water intake, diet intake, urine output, gain in body weight, urine sugar, fasting blood sugar (FBS) and glomerular filtration rate (GFR). A concentration-dependent amelioration of the diabetic status was observed with respect to all the above studied parameters. FBS of AEFD_0.1 and AEFD_0.25 groups showed a 23% and 37% reduction, respectively whereas the AFD group showed a 45% reduction relative to the SFD group. The GFR of experimental rats in AEFD_0.1 and AEFD_0.25 groups showed a 28% and 41% reduction, respectively whereas the AFD group showed a 54% reduction compared to the SFD group. The results clearly indicate that the acetone extract of elephant foot yam is an effective anti-diabetic agent for streptozotocin-induced diabetic rats.

Arumugam Madeswaran, Muthuswamy Umamaheswari, Kuppusamy Asokkumar, Thirumalaisamy Sivashanmugam, Varadharajan Subhadradevi, Puliyath Jagannath (India) Docking Studies of Aldose Reductase Inhibitory Activity of Commercially Available Flavonoids (pp 7-11)

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Original Research Paper: Molecular docking is a frequently used tool in computer-aided structure-based rational drug design. Flavonoids are a group of natural products which exhibits various biological and pharmacological activities. The primary objective of this study was to investigate the aldose reductase inhibitory activity of flavonoids using in silico docking studies. In this perspective, flavonoids like aromadedrin, eriodictyol, homoeriodictyol, isorhamnetin, okanin, pachypodol, peonidin, robinetin, tangeritin were selected. Epalrestat, a known aldose reductase inhibitor was used as the standard. In silico docking studies were carried out using AutoDock 4.2, based on the Lamarckian genetic algorithm principle. The interacting residues within the complex model and their contact types were identified. In the docking studies, three important parameters like binding energy, inhibition constant and intermolecular energy were determined. The results showed that all the selected flavonoids showed binding energy ranging between -9.20 kcal/mol to -8.02 kcal/mol when compared with that of the standard (-8.73 kcal/mol). Inhibition constant (181.13 nM to 1.32 µM) and intermolecular energy (-10.99 kcal/mol to -9.81 kcal/mol) of the flavonoids also coincide with the binding energy. All the selected flavonoids contributed aldose reductase inhibitory activity because of its structural properties. These molecular docking analyses could lead to the further development of potent aldose reductase inhibitors for the treatment of diabetes. Further investigations on the above compounds and in vivo studies are necessary to develop potential chemical entities for the prevention and treatment of diabetes.

Arumugam Madeswaran, Muthuswamy Umamaheswari, Kuppusamy Asokkumar, Thirumalaisamy Sivashanmugam, Varadharajan Subhadradevi, Puliyath Jagannath (India) Computational Drug Discovery of Potential Cyclooxygenase Inhibitors Using in Silico Studies (pp 12-15)

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Original Research Paper: New drug discovery is considered broadly in terms of two kinds of investigational activities such as exploration and exploitation. Docking of small molecules in the receptor binding site and estimation of binding affinity of the complex is a part of structure-based drug design. The current study deals with the evaluation of the cyclooxygenase inhibitory activity of flavonoids using in silico docking studies. In this perspective, flavonoids like 4-methyl esculatin, vitexycarpin, wogonin, kaempferol, acacatechin, catechin, quercetin and celecoxib were selected. Celecoxib, a known cyclooxygenase inhibitor was used as the standard. In silico docking studies were carried out using AutoDock 4.2, based on Lamarckian genetic algorithm principle. Three important parameters like binding energy, inhibition constant and intermolecular energy were determined. The results showed that all the selected flavonoids showed binding energy ranging between -7.71 and -6.09 kcal/mol when compared with that of the standard (-5.95 kcal/mol). Intermolecular energy (-9.20 to -8.18 kcal/mol) and inhibition constant (2.23 to 34.37 µM) of the ligands also coincided with the binding energy. All the selected flavonoids contributed cyclooxygenase inhibitory activity because of their structural parameters. These molecular docking analyses could lead to the further development of potent cyclooxygenase inhibitors for the treatment of inflammation.

S. Nishanth Kumar, Bala Nambisan, C. Mohandas (India) Investigation of Antifungal Activity of Stilbenes alone and in Combination with Clotrimazole against Candida albicans (pp 16-19)

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Original Research Paper: Candidiasis is a term describing infections by yeasts from the genus Candida, and the type of infection encompassed by candidiasis ranges from superficial to systemic. Treatment of such infections often requires antifungal agents such as clotrimazole, but increased use of these drugs has led to a selection of Candida sp. with increased resistance to these drugs. Antibiotics have been effective in treating infectious diseases, but resistance to these drugs has led to the emergence of new and the reemergence of old infectious diseases. In this study, we used two stilbenes [3,4',5-trihydroxystilbene (1) and 3,5-dihydroxy-4-isopropylstilbene (2)] purified from a bacterium associated with entomopathogenic nematode (EPN), to demonstrate both its intrinsic antifungal activity and its synergy with the clotrimazole, in the treatment of Candida albicans in vitro. Our results demonstrated that significant synergistic effect exists between stilbenes and Clotrimazole against C. albicans. The time kill assay also supports the synergistic activity. The cytotoxicity of stilbenes was also tested against normal human cell lines (L231 lung epithelial and folliculo-stellate (FS) normal fibroblast) and no cytotoxicity was recorded for stilbenes up to 200 µg/mL.

Rashmin B. Patel, Mrunali R. Patel, Kashyap K. Bhatt, Bharat G. Patel (India) Formulation and Evaluation of Microemulsions-Based Drug Delivery System for Intranasal Administration of Olanzapine (pp 20-27)

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Original Research Paper: This paper describes formulation considerations and in vitro evaluation of an oleic acid-based polyelectrolytic polymer-containing microemulsion drug delivery system designed for intranasal administration of a hydrophobic model drug Olanzapine. Drug-loaded microemulsions were successfully prepared by a water titration method. The microemulsion containing 4% oleic acid, 30% surfactant mixture of Labrasol: Cremophor RH 40 (1:1) : Transcutol P (3:1) and 66% (wt/wt) aqueous phase that displayed an optical transparency 99.93%, globule size 25.67 ± 1.17 nm, and polydispersity index of 0.121 ± 0.016 was selected for the incorporation of polyelectrolytic polymer (polycarbophil) as the mucoadhesive component. The mucoadhesive microemulsion formulation of Olanzapine that contains 0.5% polycarbophil (w/w) displayed higher in vitro mucoadhesive potential (19.0 ± 2.0 min) and diffusion coefficient (1.40 × 10^-6 ± 0.019 × 10^-6) than the microemulsion, followed Higuchi model, was free from nasal ciliotoxicity and stable for six months.

Rashmin B. Patel, Mrunali R. Patel, Maulik D. Chaudhari (India) Stability-Indicating High Performance Liquid Chromatographic Method for Estimation of 9-Hydroxyrisperidone in Tablet Formulation (pp 28-32)

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Original Research Paper: A stability-indicating high performance liquid chromatographic (HPLC) method for estimation of 9-hydroxyrisperidone (HRD) was developed and validated. HRD was separated and quantified on a Nucleosil C8 column (150 mm length, 4.6 mm id, 5 µm particle size) using a blend of methanol-ammonium acetate buffer pH 5.0 (95/05 v/v) as a mobile phase and at a flow rate of 1.3 mL/min. Quantification was achieved with a UV detector at 238 nm over a concentration range of 5-30 µg/mL. The applied HPLC method allowed separation and quantification of HRD with good linearity (r² – 0.999) in the studied concentration range. The limit of detection and limit of quantification were found to be 1.04 and 3.16 µg/mL, respectively. The method was validated as per the International Conference on Harmonization (ICH) guidelines. HRD stock solution was subjected to different stress conditions. The degraded product peaks were well resolved from the pure drug peak with significant differences in their retention time values. Stressed samples were assayed using the developed HPLC method. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of HRD. The method was successfully applied for the estimation of HRD in tablet dosage form.

Rashmin B. Patel, Mrunali R. Patel, Jwel B. Mehta (India) Development and Validation of HPTLC Method for Estimation of Desloratadine (pp 33-37)

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Techniques Paper: A new and rapid high-performance thin-layer chromatographic (HPTLC) method was developed and validated for quantitative determination of desloratadine. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F₂₅₄ using methanol : chloroform : toluene : ammonia (5.0+ 5.0 + 1.0 + 0.3 v/v/v/v) as mobile phase. Quantitation was achieved by densitometric analysis at 254 nm over the concentration range of 150–750 ng/mL. The method was found to give compact spot for the drug (R_f = 0.6 ± 0.01). The linear regression analysis data for the calibration plots showed good linear relationship with r² = 0.9997. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The minimum detectable amount was found to be 21 ng/spot, whereas the limit of quantitation was found to be 65 ng/spot. Statistical analysis of the data showed that the method is precise, accurate, reproducible, sensitive and selective for the analysis of desloratadine. The method was successfully employed for the estimation of desloratadine as a bulk drug and in commercially available tablet formulation.

Nitin Dubey, Ghanshyam Patil, Dinesh Kumar Jain, Subhash Chaturvedi (India) Simultaneous Estimation of Torsemide and Spironolactone in Combined Dosage Form Using Reverse Phase Liquid Chromatography (pp 38-41)

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Techniques Paper: Simple, accurate, precise, and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method for simultaneous estimation of Spironolactone (SPR) and Torsemide (TOR) in combined tablet dosage form has been developed and validated. Beer’s law was obeyed in the concentration range of 5-25 µg/mL for both drugs in methanol. The RP-HPLC method uses a Shimadzu LC 10 AT_VP system with a Luna C₁₈ column and methanol: acetonitrile: phosphate buffer, pH 3.5(60:20:20 %v/v) as the mobile phase. The detection was carried out using a diode array detector set at 238 nm. The recoveries were found to be in the range of 99.64 ± 0.04 to 100.75 ± 0.15 and 99.56 ± 0.35 to 100.33 ± 0.56 for TOR and SPR, respectively. Developed method was found to be simple, precise, sensitive and may be used for routine analysis of TOR and SPR in a pharmaceutical formulation. Results of analysis were validated statistically per ICH guidelines.

Nitin Dubey, Manju Patel, Dinesh K. Jain (India) Simultaneous Estimation of Aspirin, Atorvastatin and Clopidogrel in Combined Capsule Dosage Form Using Reverse Phase High-Performance Liquid Chromatography (pp 42-44)

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Techniques Paper: Simple, accurate and precise reversed phase high-performance liquid chromatographic (RP-HPLC) methods for simultaneous estimation of aspirin (ASP), atorvastatin (ATO) and clopidogrel (CLO) in combined capsule dosage form have been developed and validated. The RP-HPLC method uses a Shimadzu LC 10 ATVP system with a Luna C₁₈ column and acetonitrile: methanol: water (pH adjusted with ortho phosphoric acid) at pH 3.5 (50: 30: 20, v/v/v) as the mobile phase. The detection was carried out using a diode array detector set at 250 nm. Linearity of chromatographic method was found in the concentration range of 5-100, 2-24 and 5-100 µg/mL in methanol at 238, 247 and 220 nm for ASP, ATO and CLO respectively. The recoveries were in the range of 101.25 ± 0.60 for ASP, 100.34 ± 0.62 for ATO and 100.36 ± 0.60 for CLO using HPLC. These methods may be used for routine analysis of the drugs in a pharmaceutical formulation. Results of analysis were statistically validated.

Yarapa Lakshmikantha Ramachandra, Chavaan Ashajyothi, Satwadi Padmalatha Rai, Supriya Kapil Shetty Thanekar, Shirur Dakappa Shruthi (India) Antibacterial Activity of Leaf Extracts of Adhatoda vasica (pp 45-47)

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Short Communication: The present study aimed to evaluate the in vitro antimicrobial activity of pharmacologically important Adhatoda vasica plant extracts against Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Salmonella typhi.The agar well diffusion method was adopted to determine antibacterial activity against all the tested microorganisms. The selection of extracts was based on a phytochemical screening for the presence of secondary metabolites. The methanolic extract of A. vasica showed a maximum zone of inhibition (18.17 ± 0.44 mm) for S. aureus and was effective against all bacterial strains tested, thus showing antimicrobial activity. The methanolic extract of the leaves was stronger than extracts based on other solvents such as chloroform and hexane, which showed moderate to weak activity, respectively.

Harpreet Walia, Saroj Arora (India) Delineation of Antioxidant Activity of Acetone Extract/Fractions of Fruits of Terminalia chebula Using TA 102 Strain of Salmonella typhimurium (pp 48-52)

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Research Note: Antimutagenic or antioxidant properties elicited by plant species have many prospective applications in human healthcare. The fruits of Terminalia chebula are a rich source of tannins and other bioactive constituents. In Ayurveda, the plant is known as the “wonder healer” due to its extraordinary power of healing. In the present study, the Ames Salmonella histidine reversion assay was used to assess the antioxidant activity of the acetone extract of T. chebula fruits in the TA 102 strain of Salmonella typhimurium using hydrogen peroxide (H₂O₂) as a direct acting oxidant. The acetone extract was prepared by maceration and further fractionated with ethyl acetate and water. The antioxidant activity of ethyl acetate and water fractions was comparatively higher than that of the crude extract. The ethyl acetate fraction inhibited reduction of H₂O₂ by 72.48 and 72.83% in co and pre-incubation modes, respectively although there was no difference in co- and pre-incubation modes of experimentation.