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Publications (10)5.54 Total impact

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    ABSTRACT: The present invention relates to exploiting the interaction of chromogenic/germinogenic substrate(s) with marker enzymes to develop assay for detection of L. monocytogenes in a milk sample. The said assay detects chromogenic / fluorogenic signal, which in turn indicates the presence or absence of target microorganism. The invention enables the rapid detection of L. monocytogenes in two stages. The stage -1 involves development of selective enrichment medium LSEM which ensures presumptive detection of Listeria spp., thus enabling the detection of target microorganism at genus level. The developed medium proves to be selective as growth of potential contaminants like L. fermentum, L. casei, B. cereus, S aureus and E. faecalis were significantly inhibited. The growth of L. monocytogenes is selectively enhanced which is evident from remarkable increase in its enumeration counts from 5.3 log counts to 9.12 log counts within 13.15 ±0.20h of incubation at 37°C. In stage -2, after pre-enrichment cells harvested from stage -1 and target organism i.e. L. monocytogenes can be detected up to species level following two different approaches. In first approach i.e. chromogenic assay cells were allowed to react with chromogenic substrate mixture for different marker enzymes(s), thus enabling confirmation at species level based on color change. In another approach i.e. spore based assay, enriched cells were incubated with specific combination of germinogenic substrates and B. megaterium spores. The spore based assay detects presence of target organism on the basis of characteristic and unique fluorogenic signals for different germinogenic substrates. The signals arise from spore germination triggered by enzymatic action of specific marker enzymes of L. monocytogenes on combination of germinogenic substrates. The assay is highly rapid and sensitive as the said assay enables the detection of target microorganism i.e. L. monocytogenes 10±2.0 cfu/mL in 4.30±0.30h and 3.30±0.30 h after pre-enrichment in LSEM up to a period of 24.0±1.0h and 16.0 ± 1.0 h in chromogenic assay and spore based assay respectively. The current innovation has immense industrial importance in view of enhanced food safety concern globally and legislation for L. monocytogenes in milk and milk products.
    Ref. No: 1357/DEL/2013, Year: 10/2013
  • International Orthopaedics 01/2012; · 2.02 Impact Factor
  • Indian Journal of Biotechnology 07/2011; 10(3):274-284. · 0.51 Impact Factor
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    ABSTRACT: Nature gifted us with oxygenated steroids 3, 6, 17-trihydroxy stigmasta-4,7, 24(28)-triene (A) and 14, 15, 18, 20-diepoxyturbinarin (B) to quench our thirst of isolating steroids from the highest antimicrobial active cyclohexane soluble extract of Turbinaria conoides (family: Sargassaceae), which were characterized by spectral analyses. Cytotoxic oxygenated fucosterols have been reported from the ethyl acetate extract of Turbinaria conoides. The purpose of this investigation was to evaluate the isolated steroids for their response to acetylcholine induced contraction on frog rectus abdominus muscle by in vitro standard method as certain steroids have been reported for cholinergic, anticholinergic activity as well. Compound A significantly inhibited acetylcholine induced contraction with EC50 (50% effective concentration) of 16 μg/mL (P<0.05) and produced a shift to the right on the dose response curve as exhibited by Pancuronium a positive control. The potency and affinity were exhibited by significant increase (P<0.05) in the mean EC50 values of 1.66±0.02 M (acetylcholine alone) to 2.52±0.15 M (acetylcholine with compound A) and decrease in the mean pA2 values of 0.82±0.08 M (acetylcholine alone) to 0.47±0.11 M (acetylcholine with compound A) respectively. Compound B potentiated acetylcholine response by 2 fold at EC50 level of 20 μg/mL, signifying estrogenic nature of cholinergic activity. Hence Turbinaria conoides has joined the band of elite species that possess both cholinergic and anticholinergic activities, thus proving to be an exquisite treasure chest for further research.
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    ABSTRACT: Nature gifted us with oxygenated steroids 3, 6, 17-trihydroxy stigmasta-4,7, 24(28)-triene (A) and 14, 15, 18, 20-diepoxyturbinarin (B) to quench our thirst of isolating steroids from the highest antimicrobial active cyclohexane soluble extract of Turbinaria conoides (family: Sargassaceae), which were characterized by spectral analyses. Cytotoxic oxygenated fucosterols have been reported from the ethyl acetate extract of Turbinaria conoides. The purpose of this investigation was to evaluate the isolated steroids for their response to acetylcholine induced contraction on frog rectus abdominus muscle by in vitro standard method as certain steroids have been reported for cholinergic, anticholinergic activity as well. Compound A significantly inhibited acetylcholine induced contraction with EC50 (50% effective concentration) of 16 μg/mL (P<0.05) and produced a shift to the right on the dose response curve as exhibited by Pancuronium a positive control. The potency and affinity were exhibited by significant increase (P<0.05) in the mean EC50 values of 1.66±0.02 M (acetylcholine alone) to 2.52±0.15 M (acetylcholine with compound A) and decrease in the mean pA2 values of 0.82±0.08 M (acetylcholine alone) to 0.47±0.11 M (acetylcholine with compound A) respectively. Compound B potentiated acetylcholine response by 2 fold at EC50 level of 20 μg/mL, signifying estrogenic nature of cholinergic activity. Hence Turbinaria conoides has joined the band of elite species that possess both cholinergic and anticholinergic activities, thus proving to be an exquisite treasure chest for further research.
    Planta Medica 08/2010; 76(12):1356. DOI:10.1055/s-0030-1264933 · 2.34 Impact Factor
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    ABSTRACT: Brown alga, Turbinaria conoides was successively extracted with n-hexane, cyclohexane, methanol and ethanol:water (1:1). The extracts were evaluated for antibacterial and antifungal activities by disc diffusion method. Minimal inhibitory concentration was determined for active extracts by broth dilution method. The antiviral activity and cytotoxicity of the extracts were tested in human embryonic lung (HEL) cells (herpes simplex virus-1, herpes simplex virus-2, vaccinia virus, vesicular stomatitis virus and herpes simplex virus-1 TK- KOS ACVr), human epithelial (HeLa) cells (vesicular stomatitis virus and coxsackie virus B4) and Vero cells (parainfluenza-3 virus, reovirus-1, sindbis virus coxsackie virus B4 and punta toro virus). The results revealed that extracts exhibited cytotoxicity ranged from 20 to >100 μg/mL. Moderate activity was demonstrated by n-hexane and cyclohexane extracts against viruses, whereas methanol and ethanol:water (1:1) extracts were not active. Ethanol:water (1:1) presented neither antibacterial nor antifungal activity against tested organisms. Cyclohexane extract possessed a broad array of antibacterial activity and exhibited remarkable antifungal property. It is noteworthy that minimal inhibitory concentration of cyclohexane extract against Aspergillus niger is comparable with that of clotrimazole. This potentiality demonstrates that it could be used to treat bacterial and fungal infections.
    Iranian journal of pharmaceutical research (IJPR) 01/2010; 9(4):411-416. · 0.51 Impact Factor
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    ABSTRACT: Scientific documentation of cytotoxicity and traditional claims as an antibacterial prompted an in-depth study of the brown alga Turbinaria conoides (family: Sargassaceae). By activity-guided fractionation of cyclohexane extract, a bioactive steroid was identified as fucosterol. The structure was confirmed unambiguously by comparing with the reported physical and spectral data of the compound. Further the compound was subjected to comprehensive pharmacological screening. It exhibited moderate antibacterial and significant antifungal activity against Candida albicans at MIC value of 8 µg/ml, possessed anti-Feline Corona virus and anti-Feline Herpes virus activity at >4 µg/ml with CC50 of 16.1 µg/ml in Cradell-Rees Feline kidney cells assessed by colorimetric formazan-based MTS assay. This compound also showed significant antihistaminic and anticholinergic properties with EC50 values of 8 µg/ml and 20 µg/ml, respectively. Hence, fucosterol proved to be a treasure trove for pharmacological research.
    The 50th Anniversary meeting of the American Society of Pharmacognosy; 06/2009
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    ABSTRACT: In the Indian system of medicine, Dikamali has been used as an antispasmodic, anthelmintic, expectorant and antiseptic. However, very little is known regarding the scientific documentation of gardenin B of Dikamali. The aim of this present study was to explore antihistaminic property of various derivatives of gardenin B using a semisynthetic approach. Gardenin B (5-hydroxy 6, 7, 8, 4’-tetramethoxy flavone) was eluted with chloroform-ethyl acetate (9:1) from the ether extract of Dikamali resin, whose source species is Gardenia gummifera L. (family: Rubiaceae). Derivatives of gardenin B include phenylhydrazone and benzoylated compounds. Gardenin B and its derivatives were characterized by spectral analyses. They exhibited a broad array of antibacterial activity. Preparation of phenylhydrazone of gardenin B abolished the antihistaminic activity. Gardenin B and its benzoate possessed significant antihistaminic activity on guinea pig ileum, with gardenin B benzoate being the most active, with an EC50 value of 16 µg/ml. This approach demonstrated that gardenin B benzoate was a novel analogue with potent antihistaminic activity.
    The 50th Anniversary meeting of the American Society of Pharmacognosy; 06/2009
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    ABSTRACT: Fucosterol (Stigmasta-5,24(28)-dien-3-ol) was isolated from cyclohexane extract of Turbinaria conoides (J.Agardh) Kutzing. The structure was identified by comparing with the reported physical and spectral data of the compound. The antihistaminic and anticholinergic activities have been evaluated using in vitro standard animal models in comparison to chlorpheniramine maleate and pancuronium respectively. Evaluation of the potency (EC50), affinity (pA2) of the fucosterol and the maximal response (Emax) to the Histamine and acetylcholine were determined in the absence and presence of fucosterol. Antiviral activity and cytotoxicity were performed in human embryonic lung, human epithelial and Vero cells. Fucosterol showed antiviral activity against tested viruses with EC50 values ranging from >4 μg/mL to >20 μg/mL in the cells. Fucosterol inhibited histamine (97%) and acetylcholine (94%) induced contractions at 20 μg/mL, which were comparable to that of 10 μg/mL of chlorpheniramine maleate and pancuronium respectively. Thus Fucosterol springs up to be potent antihistaminic and anticholinergic compound.
    Pharmacologyonline 04/2009; 1:1104-1112. · 0.16 Impact Factor
  • Khan, Shah Alam
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    ABSTRACT: Thesis (M. S.)--Cornell University, May, 1973. Bibliography: l. 89-92.