Butyrylcholinesterase Inhibitory Guaianolides from Amberboa ramosa

Sher Bahadar Khan,Azhar-ul-Haq,Shagufta Perveen,Nighat Afza,Abdul Malik,Sarfraz Ahmad Nawaz,Muhammad Raza Shah,Muhammad Iqbal Choudhary 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.2

Phytochemical investigation of the whole plant of Amberboa ramosa led to the isolation of six sesquiterpene lactones which could be identified as 8α-hydroxy-11β−methyl-1αH, 5αH, 6βH, 7αH, 11αH-guai-10(14), 4(15)-dien-6, 12-olide(1), 3β, 8α-dihydroxy-11α−methyl-1αH, 5αH, 6βH, 7αH, 11βH-guai-10(14), 4 (15)-dien-6, 12-olide (2), 3β, 4α, 8α-trihydroxy-4β-(hydroxymethyl)- 1αH, 5αH, 6βH, 7αH-guai-10(14), 11(13)-dien-6, 12-olide (3), 3β, 4α, 8α-trihydroxy-4β- (chloromethyl)-1αH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6, 12-olide(4), 3β, 4α, dihydroxy- 4β-(hydroxymethyl)-1αH, 5αH, 6βH, 7αH-guai-10(14),11(13)-dien-6, 12-olide(5), 3β, 4α-dihydroxy- 4β- (chloromethyl)-8α-(4-hydroxymethacrylate)-1αH, 5αH, 6βH, 7αH-guai-10(14),11 (13)-dien-6,12-olide (6) by spectroscopic methods. All of them showed inhibitory potential against butyrylcholinesterase.

Isolation and Biochemical Characterization of Collagens from Seaweed Pipefish, Syngnathus Schlegeli

Sher Bahadar Khan,천충길,유보미,Se-Kwon Kim 한국생물공학회 2009 Biotechnology and Bioprocess Engineering Vol.14 No.4

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the seaweed pipefish (Syngnathus schlegeli) and partially characterized. The amount of collagens isolated in the subsequent treatments was 5.5% of ASC and 33.2% PSC on the basis of lyophilized pipefish body weight, respectively. According to the electrophoretic pattern and CM-cellulose column chromatogram, the collagens might be classified as type I collagens, containing α1 and α2 chain. The imino acid content of collagen from pipefish was lower than those of mammalian collagens as also were the denaturation temperatures (Td) of collagens were 34.8°C and 35.1°C, respectively. This study shows that there is a possibility to use pipefish collagen as the alternative source of collagen from industrial purposes and subsequently it may evaluate the economical value of the seaweed pipefish.

Assessment of antibacterial cellulose nanocomposites for water permeability and salt rejection

Sher Bahadar Khan,Khalid A. Alamry,Elham N. Bifari,Abdullah M. Asiri,Muhammad Yasir,Lassaad Gzara,Rehan Zulfiqar Ahmad 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.24 No.-

Anti-bacterial nanocomposites (NC1–NC4) based on cellulose acetate were prepared by dispersing ZnO nanofillers in the cellulose acetate matrix. Anti-bacterial nanocomposites were structurally and morphological examined by XRD (X-ray powder diffraction), FESEM (field emission scanning electron microscopy), and FT-IR (Fourier transform infrared) spectroscopy. All the spectroscopic techniques suggested that nanocomposites are successfully synthesized. All the nanocomposites showed antibacterial activity which increased as a function of zinc oxide. Further the selectivity of anti-bacterial nanocomposites was investigated toward different metal ions, including Zn2+, Cd2+, Pb2+, Mn2+, Ni2+, Fe2+, Al3+, Sb3+, and Sr3+. The selectivity data suggests that nanocomposites are more selective toward Fe2+. NC1 displayed highest uptake aptitude for Fe2+ with highest distribution coefficient of 7549.123 mL g1. Therefore, NC1 was subjected to water permeability to explore the role of antibacterial nanocomposite as membrane for water purification. The results suggest that these materials are possibly appropriate for water treatments.

Synthesis and Characterization of Novel PPC-Silica Hybrid with Improved Thermal, Mechanical, and Water Sorption Properties

Sher Bahadar Khan,한학수,서종철,장의성,Kalsoom Akhtar,김광인 한국고분자학회 2011 Macromolecular Research Vol.19 No.9

Organic-inorganic hybrids (H1-H5) based on environmentally friendly and biodegradable polymer, poly (propylene carbonate) (PPC) and tetraethoxysilane (TEOS) were synthesized using the sol-gel technique. The synthesized hybrids were characterized structurally and morphologically by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). H1-H5 were examined in term of detailed thermal, mechanical, and anti-water sorption properties using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) nanoindentation, and thin film diffusion analysis, which revealed that H4 has the highest thermal, mechanical, and anti-water sorption properties. H4 greatly increased the thermal decomposition temperature (Td10%) and glass transition temperature, which are 45 and 11 ℃ higher than that of pure PPC. Accordingly, H4 showed a high storage modulus (2.54 × 109 Pa), elastic modulus (2.601± 0.110 GPa), hardness (0.175 ± 0.013 GPa), and lowest water absorption. This improvement in the thermal, mechanical,and anti-water absorption properties of PPC shows that PPC can be used as a packaging and bio-material.

Development of electrochemical sensor based on layered double hydroxide as a marker of environmental toxin

Sher Bahadar Khan,Abdullah M. Asiri,Kalsoom Akhtar,Malik Abdul Rub 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

Zinc/vanadium layered double hydroxide (LDH) was prepared and its functional relationships withthiourea were investigated in order to develop a sensor for the recognition of this toxin. Sensortechnology is one of the major recognition methods and has shown potential applications inenvironmental monitoring, but issues of sensitivity, selectivity, and high cost related to this technologystill need to be resolved in order to allow their more extensive use. Our study therefore focused on thedevelopment of a low-cost selective and sensitive thiourea sensor. This was developed using LDH whereits sensing potential was investigated by a simple I–V technique. The developed sensor exhibited highsensitivity (1.004 mA mM cm 2), lower limit of detection (8.4 mM) and wide range of linear dynamics(10–500 mM). The selectivity was studied using different interfering agents and it was found that thedeveloped sensor is more selective toward thiourea. The sensor behavior was further optimized usingbuffers of different pH.

Synthesis of nanopartical by encapsulation of flavor molecules into layered double hydroxides for controlled release of flavor

Sher Bahadar Khan,유창지,한학수 한국고분자학회 2010 한국고분자학회 학술대회 연구논문 초록집 Vol.2010 No.4

PPC와 Organo-Clay 나노 조성물의 합성과 실리카층의 수분흡수와 열적특성에 대한 영향

Sher Bahadar Khan,Jongchul Seo,Eui Sung Jang,Joon Suk Choi,Seunghyuk Choi,Haksoo Han 한국막학회 2009 멤브레인 Vol.19 No.4

Poly propylene carbonate (PPC)와 cloisite 20B (PPC/C-20B)을 solution method를 통하여 합성하였고, 이를 통해 합성된 나노 조성물의 morphology, 열적 특성, 수분 흡수의 특성을 평가하였다. 나노 조성물의 구조는 X-ray diffraction (XRD) 로 확인하였고, 열적 특성은 thermal gravimetric analysis (TGA)와 differential scanning calorimetric (DSC)를 이용해 분석하였다. TGA와 DSC의 결과를 통해 나노 조성물은 기존의 PPC에 비해 높은 열적 안정성을 가짐을 확인할 수 있었다. DSC측정에서 5 wt%의 clay를 포함한 nanohybrid의 유리전이온도는 순수한 PPC의 21℃에서 30℃로 9℃ 증가하였고, TGA 측정을 통해 확인한 열분해온도(Td50%)는 순수 PPC에 비해 23℃가 높아졌음을 확인하였다. 또한 PPC 나노 조성물의 수분 흡수량은 기존의 PPC에 비해 상당히 감소하였다. 이는 clay의 PPC matrix 구조 내에 존재함으로 인해 수분 흡수를 감소시킨 것으로 해석할 수 있다. 수분 흡수는 코팅 막의 분해를 유발하고 물리적, 기계적 성능에 영향을 미친다. 따라서 나노 조성물로 인한 PPC의 열적 안정성, 수분흡수도 향상은 PPC의 사용과 실제 공정에 중요한 변수로 작용할 수 있다. Nanohybrid based on environmentally friendly and biodegradable polymer, poly propylene carbonate (PPC) and cloisite 20B (PPC/C-20B) have been synthesized by solution blending method and their morphology, thermal and water absorption properties have been evaluated. The structure of PPC/C-20B nanohybrid was confirmed by X-ray diffraction (XRD). The thermal property of PPC and PPC/C-20B nanohybrid were investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetric (DSC). The experimental results demonstrated that nanohybrid showed the highest thermal stability in TGA and DSC. TGA tests revealed that the thermal decomposition temperature (Td50%) of the nanohybrid increased significantly, being 23℃ higher than that of pure PPC while DSC measurements indicated that the introduction of 5 mass% of clay increased the glass transition temperature from 21 to 30℃. Further the water absorption capacity of the PPC was significantly decreased by the incorporation of clay. Water absorption cause degradation of the coating by the moistures and affect the physical and mechanical performance. This result indicates that organic modifiers have effect on thermal and water absorption capacity of PPC and are of importance for the practical process and application of PPC.

The Impact of Capital Structure on Firm Performance: Evidence from Pakistan

Hussain Muhammad,Bahadar Shah,Zia ul Islam 한국유통과학회 2014 The Journal of Industrial Distribution & Business( Vol.5 No.2

Purpose The purpose of this – study is to empirically investigate the impact of capital structure on firm performance. Research design, data, and methodology – This study examined the impact of capital structure on the performance of cement companies listed on the Karachi Stock Exchange during the period 2009-2013. The authors hypothesize that there is a negative relationship between capital structure and firm performance. To examine the association, the authors run a Pearson correlation and multiple regression analysis. Results – Results reveal a strong negative relationship between debt to asset and firm performance variables (GPM, NPM, ROA, and ROE). Further, there is a positive relationship between debt to equity and firm performance variables (GPM and NPM), anda negative relationship between debt to equity and firm performance variables (ROA and ROE). Moreover, capital structure variables significantly impact firm performance. Conclusions – This study concluded that financial analysts and managers should emphasize on the optimal level of capital structure and efficient utilization and allocation of resources to achieve the targeted level of productive efficiency in business

Protective Effect of Amphiroa dilatata on ROS Induced Oxidative Damage and MMP Expressions in HT1080 Cells

Khan, Sher Bahadar,Kong, Chang-Suk,Kim, Jung-Ae,Kim, Se-Kwon 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.1

Antioxidative and matrix metalloproteinase (MMP) inhibitory effects of methanolic extract from Amphiroa dilatata were investigated in HT1080 cells. Treatment with A. dilatata extract suppressed the intensity of electron spin resonance signal on the generation of DPPH radicals in a cell-free system and intracellular reactive oxygen species (ROS) formation by 2',7'-dichlorofluorescin diacetate (DCFH-DA). Radical simulated oxidation of membrane proteins and lipids were also inhibited by treatment with A. dilatata extract in a concentration-dependent manner. In addition, a protective effect on oxidative damage of purified genomic DNA was observed in the presence of A. dilatata extract. These results revealed that A. dilatata has an excellent scavenging ability on ROS-induced oxidative damage. Moreover, this extract reduced the expression levels of MMP-2 and -9 in gelatin zymography, and RT-PCR analysis without any cytotoxic influence. Therefore, A. dilatata has a promising potential as a valuable source to be used as ingredient in functional foods, related to oxidative damage.

Butyrylcholinesterase Inhibitory Guaianolides from Amberboa ramosa

Khan Sher Bahadar,Haq Azhar-ul,Perveen Shagufta,Afza Nighat,Malik Abdul,Nawaz Sarfraz Ahmad,Shah Muhammad Raza,Choudhary Muhammad lqbal The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.2

Phytochemical investigation of the whole plant of Amberboa ramosa led to the isolation of six sesquiterpene lactones which could be identified as $8{\alpha}$-hydroxy-$11{\beta}$-methyl-$1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H,\;11{\alpha}H-guai-10(14)$, 4(15)-dien-6, 12-olide(2), $3{\beta},\;8{\alpha}-dihydroxy-11{\alpha}-methyl-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H,\;11{\beta}H-guai-10(14)$, 4(15)-dien-6, 12-olide (2), $3{\beta},\;4{\alpha},\;8{\alpha}-trihydroxy-4{\beta}(hydroxymethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide (3), $3{\beta},\;4{\alpha},\;8{\alpha}-trihydroxy-4{\beta}-(chloromethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide(4), $3{\beta},\;4{\alpha},\;dihydroxy-4{\beta}-(hydroxymethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide(5), $3{\beta},\;4{\alpha}-dihydroxy-4{\beta}-(chloromethyl)-8{\alpha}-(4-hydroxymethacrylate)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide (6) by spectroscopic methods. All of them showed inhibitory potential against butyrylcholinesterase.