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Cytotoxic Effects of Polymethoxyflavones Isolated from Kaempferia parviflora
Hossain, Md. Alamgir,Wongsrikaew, Natcha,Yoo, Gwi-Woong,Han, Jaehong,Shin, Cha-Gyun The Korean Society for Applied Biological Chemistr 2012 Applied Biological Chemistry (Appl Biol Chem) Vol.55 No.4
Although several studies covered anti-proliferative and cytotoxic effects of the rhizome extracts of Kaempferia parviflora Wall. Ex. Baker towards cancer cells, cytotoxicity of its pure methoxyflavone components remains undetermined. The present study was aimed to evaluate the cytotoxicity of 3,5,7,4'-tetramethoxyflavone (TeMF), 5,7,4'-trimethoxyflavone (TMF), and 5-hydroxy-3,7,3',4'-tetramethoxyflavone (5-H-TeMF) purified from its rhizome extracts on human colorectal carcinoma (HCT-15) cells. All three compounds showed a dose-dependent inhibitory effect on HCT-15 cells. Significant numbers of apoptotic nuclei and condensed chromatin were also observed. TMF produced a higher level of fragmented DNA compared to TeMF and 5-H-TeMF. In addition TMF-treated cells showed the highest levels of caspase-3 activity than those treated with the other two compounds. Caspase-3 activity was reduced when Z-VAD-FMK, a caspase inhibitor, was administered along with each compound. Furthermore, caspase-3 activity was increased by the four concentrations of TMF in a dose-dependent manner. These results strongly suggest that TeMF, TMF, and 5-H-TeMF caused cell death via an apoptotic pathway. Therefore all these compounds have the potentiality to be the novel anti-cancer drugs.
Hossain, Md. Alamgir,Ali, Md. Khadem,Shin, Cha-Gyun Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.2
We identified four basic amino acid residues as nuclear localization signals (NLS) in the C-terminal domain of the prototype foamy viral (PFV) integrase (IN) protein that were essential for viral replication. We constructed seven point mutants in the C-terminal domain by changing the lysine and arginine at residues 305, 308, 313, 315, 318, 324, and 329 to threonine or proline, respectively, to identify residues conferring NLS activity. Our results showed that mutation of these residues had no effect on expression assembly, release of viral particles, or in vitro recombinant IN enzymatic activity. However, mutations at residues 305 (R ${\rightarrow}$ T), 313(R ${\rightarrow}$ T), 315(R ${\rightarrow}$ P), and 329(R ${\rightarrow}$ T) lead to the production of defective viral particles with loss of infectivity, whereas non-defective mutations at residues 308(R ${\rightarrow}$ T), 318(K ${\rightarrow}$ T), and 324(K ${\rightarrow}$ T) did not show any adverse effects on subsequent production or release of viral particles. Sub-cellular fractionation and immunostaining for viral protein PFV-IN and PFV-Gag localization revealed predominant cytoplasmic localization of PFV-IN in defective mutants, whereas cytoplasmic and nuclear localization of PFV-IN was observed in wild type and non-defective mutants. However sub-cellular localization of PFV-Gag resulted in predominant nuclear localization and less presence in the cytoplasm of the wild type and non-defective mutants. But defective mutants showed only nuclear localization of Gag. Therefore, we postulate that four basic arginine residues at 305, 313, 315 and 329 confer the karyoplilic properties of PFV-IN and are essential for successful viral integration and replication.
An Exploratory Study of Subscribers’ Attitude toward Mobile Advertising
Alamgir Hossain,Bangwool Han,Minho Kim 전북대학교 산업경제연구소 2017 아태경상저널 Vol.9 No.2
The prompt diffusion of mobile phone has resulted in the increasing usage of mobile advertisement. A significant number of firms have invested their knowledge and resources in this field, and to develop a successful strategy they need proper understanding about advertisement and its contents. Purpose of this study was to revisit the underlying factors affecting consumer attitude toward mobile advertising in Bangladesh. Based on the empirical studies regarding attitude toward mobile advertising, a questionnaire was developed and 355 mobile subscribers were taken into considerations. Five variables i.e. personalization, credibility, incentive, informativeness and entertainment were selected and analyzed through structural equation model. Results portrait that entertainment followed by informativeness and credibility are the most dominant factors and has motivational influence on consumer attitude toward advertisement. Findings forge ahead the current state of art in mobile marketing research with substantial practical contributions for the design of operative mobile advertising.
Cytotoxic Effects of Polymethoxyflavones Isolated from Kaempferia parviflora
Md. Alamgir Hossain,Natcha Wongsrikaew,Gwi-Woong Yoo,한재홍,신차균 한국응용생명화학회 2012 Applied Biological Chemistry (Appl Biol Chem) Vol.55 No.4
Although several studies covered anti-proliferative and cytotoxic effects of the rhizome extracts of Kaempferia parviflora Wall. Ex. Baker towards cancer cells, cytotoxicity of its pure methoxyflavone components remains undetermined. The present study was aimed to evaluate the cytotoxicity of 3,5,7,4'-tetramethoxyflavone (TeMF), 5,7,4'-trimethoxyflavone (TMF),and 5-hydroxy-3,7,3',4'-tetramethoxyflavone (5-H-TeMF) purified from its rhizome extracts on human colorectal carcinoma (HCT-15) cells. All three compounds showed a dose-dependent inhibitory effect on HCT-15 cells. Significant numbers of apoptotic nuclei and condensed chromatin were also observed. TMF produced a higher level of fragmented DNA compared to TeMF and 5-HTeMF. In addition TMF-treated cells showed the highest levels of caspase-3 activity than those treated with the other two compounds. Caspase-3 activity was reduced when Z-VAD-FMK,a caspase inhibitor, was administered along with each compound. Furthermore, caspase-3 activity was increased by the four concentrations of TMF in a dose-dependent manner. These results strongly suggest that TeMF, TMF, and 5-H-TeMF caused cell death via an apoptotic pathway. Therefore all these compounds have the potentiality to be the novel anti-cancer drugs.
Md. Alamgir Hossain,Min-Ho Kim,Nusrat Jahan,Bo-Yeon Min 강원대학교 경영경제연구소 2018 Asia-Pacific Journal of Business Vol.9 No.2
As competition grows in the telecommunication service industry, understanding the origins of brand image and consumer behavioral intentions challenges practitioners to design an effective marketing strategy and branding plan. In this paper, brand image and behavioral relationships are investigated in Bangladesh, an emerging market that has a particular socio-cultural and economic context of one of the most densely populated countries of South Asia. This study employs confirmatory factor analysis and structural equation modeling to analyze the database. Empirical testing and the proposed model suggest that brand image is the prime determinant of consumer satisfaction and loyalty. The results highlight the importance of perceived value, perceived trust and price structure to project brand image and satisfaction. Additionally, confirmation exhibits a stronger total effect of brand image on customer loyalty. Empirical findings extensively contribute to the theoretical and managerial understanding of subscribers’ attitudes toward telecommunication service in an emerging market context.
Md. Alamgir Hossain,Md. Khadem Ali,신차균 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.2
We identified four basic amino acid residues as nuclear localization signals (NLS) in the C-terminal domain of the prototype foamy viral (PFV) integrase (IN) protein that were essential for viral replication. We constructed seven point mutants in the C-terminal domain by changing the lysine and arginine at residues 305, 308, 313, 315, 318, 324, and 329 to threonine or proline, respectively, to identify residues conferring NLS activity. Our results showed that mu-tation of these residues had no effect on expression assembly, release of viral particles, or in vitro recombinant IN enzymatic activity. However, mutations at residues 305 (R → T), 313(R → T), 315(R → P), and 329(R → T) lead to the production of defective viral particles with loss of infectivity, whereas non-defective mutations at residues 308(R → T), 318(K → T), and 324(K → T) did not show any adverse effects on subsequent production or release of viral particles. Sub-cellular fractionation and immunostaining for viral protein PFV-IN and PFV-Gag localization revealed predominant cytoplasmic localization of PFV-IN in defective mutants, whereas cytoplasmic and nuclear localiza-tion of PFV-IN was observed in wild type and non-defective mutants. However sub-cellular localization of PFV-Gag re-sulted in predominant nuclear localization and less pre-sence in the cytop-lasm of the wild type and non-defective mutants. But defective mutants showed only nuclear localization of Gag. Therefore, we postulate that four basic arginine residues at 305, 313, 315 and 329 confer the karyoplilic properties of PFV-IN and are essential for successful viral integration and replication.