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The polyion complex-based supramolecular self-assembly of hexagonal nanosheets was achieved via the complexation of a PEGylated block catiomer with ATP and other polyphosphate-containing small molecules. The formation of hexagonal nanosheets required the presence of a polyethylene glycol block and α-helix formation in the catiomer block, which was induced by complexation with the polyphosphate moiety. [ABSTRACT FROM AUTHOR]

Developing nanovehicles for delivering antibiotics is a promising approach to overcome the issue of antibiotic resistance. This study aims to utilize a polyion complex (PICs) system for developing novel nanovehicles for polymyxin‐type antibiotics, which are known as last resort drugs. The formation of antibiotic‐based PIC nanostructures is investigated using colistimethate sodium (CMS), an anionic cyclic short peptide, and a series of block catiomers bearing different amounts of guanidinium moieties on their side chains. In addition, only the modified catiomer, and not the unmodified catiomer, self‐assembles with CMS, implying the importance of the guanidine moieties for enhancing the interaction between the catiomer and CMS via the formation of multivalent hydrogen bonding. Moreover, micellar and vesicular PIC nanostructures are selectively formed depending on the ratio of the guanidine residues. Size‐exclusion chromatography reveals that the encapsulation efficiency of CMS is dependent on the guanidinium modification ratio. The antimicrobial activity of the PIC nanostructures is also confirmed, indicating that the complexation of CMS in the PICs and further release from the PICs successfully occurs. [ABSTRACT FROM AUTHOR]

Abstract: Lactic acid bacterium isolated from fermented durian (tempoyak) was investigated for its potentials as a probiotic strain. Bacterial tolerance toward gastrointestinal environment, adhesion, and cytotoxic activity in human colon adenocarcinoma cell line HT‐29 was evaluated. 16S rRNA sequencing identified the lactic acid bacterium as Lactobacillus plantarum. The bacterium demonstrated good tolerance toward gastrointestinal pH 2.0 and 0.3% bile salts. It showed strong adhesive capacity in human intestinal cell line, HT‐29, with an adhesion index of 159 ± 10. Cytotoxicity of L. plantarum was investigated using both live bacterial cells (BC) and cell‐free supernatant (CFS). Findings showed that both BC and CFS of L. plantarum reduced proliferation of HT‐29 colon adenocarcinoma cells using MTT assay. The results imply potential probiotic properties of L. plantarum isolated from tempoyak. [ABSTRACT FROM AUTHOR]

Hibiscus sabdariffa Linn. or also known as roselle which is rich in polyphenols, has been demonstrated to cause lowering of blood pressure in animal and clinical settings. However its exact mechanism of action particularly from polyphenolic compounds is not clearly understood. Therefore, we aimed to determine the effects of H. sabdariffa polyphenol extract (HPE) towards vascular reactivity and its mechanism of action. The HPE was studied on isolated thoracic aortic rings from normal Sprague-Dawley rats, suspended in a 15-ml organ chambers containing Krebs-Henseleit solution. The changes in tension were recorded by isometric transducer connected to data acquisition. HPE relaxed the contraction induced by phenylephrine (PE, 1µM) in similar pattern for both endothelium-intact and endothelium denuded aortic rings in dose-dependent manner 0.1 ~ 0.9 mg/ml. The pretreatment with atropine (1µM), a competitive muscarinic antagonist, and propranolol (1µM), a non-selective beta- blocker did not alter HPE vasorelaxation response. In addition, HPE did not inhibit the contraction induced by extracellular Ca2+ precontracted by PE (1 µM) or KCl (60 mM), in Ca2+ -free solution, suggesting that the relaxation effect of HPE was not via inhibition of calcium channels. In conclusion, HPE demonstrated vasorelaxation effects on rat thoracic aorta although the underlying mechanism is still unknown. The vasorelaxation effect could be via angiotensin type 1 receptor inhibition in the vascular smooth muscle cells or the activation of hyperpolarizing K+ channel. [ABSTRACT FROM AUTHOR]

Mutagenic and antimutagenic activities of lactic acid bacteria (LAB) Lactobacillus plantarum isolated from the local fermented durian (tempoyak) was determined by Ames test (Salmonella/microsome mutagenicity assay). Our study also involved pre-incubation assay against Salmonella typhimurium TA 98 and TA 100 bacterial strain in the presence and absence of metabolic activator S9 system. It was found that the L. plantarum showed no mutagenic activity on both S. typhimurium strain TA 98 and TA 100 in the presence and absence of metabolic activator. Significant antimutagenic activity (p < 0.05) was observed in both cell-free supernatant and bacterial cell suspension of L. plantarum as compared to the mutagenicity induced by 2-Aminoanthracene in the presence of metabolic activator. Meanwhile, in the absence of metabolic activator, only the bacterial cells of L. plantarum showed antimutagenicity acitivity against Sodium Azide and 2-Nitrofluorene. In conclusion, L. plantarum could play a vital role as chemopreventive agent by binding to mutagens and suppressing mutagenesis. Thus, L. plantarum could be consider as a good candidate for functional food development as a supplement product to prevent development of colon cancer. [ABSTRACT FROM AUTHOR]

Hibiscus sabdariffa Linn. or also known as roselle which is rich in polyphenols, has been demonstrated to cause lowering of blood pressure in animal and clinical settings. However its exact mechanism of action particularly from polyphenolic compounds is not clearly understood. Therefore, we aimed to determine the effects of H. sabdariffa polyphenol extract (HPE) towards vascular reactivity and its mechanism of action. The HPE was studied on isolated thoracic aortic rings from normal Sprague-Dawley rats, suspended in a 15-ml organ chambers containing Krebs-Henseleit solution. The changes in tension were recorded by isometric transducer connected to data acquisition. HPE relaxed the contraction induced by phenylephrine (PE, 1 μM) in similar pattern for both endothelium-intact and endothelium denuded aortic rings in dose-dependent manner 0.1 ~ 0.9 mg/ml. The pretreatment with atropine (1 μM), a competitive muscarinic antagonist, and propranolol (1 μM), a non-selective beta- blocker did not alter HPE vasorelaxation response. In addition, HPE did not inhibit the contraction induced by extracellular Ca2+ precontracted by PE (1 μM) or KCl (60 mM), in Ca2+ -free solution, suggesting that the relaxation effect of HPE was not via inhibition of calcium channels. In conclusion, HPE demonstrated vasorelaxation effects on rat thoracic aorta although the underlying mechanism is still unknown. The vasorelaxation effect could be via angiotensin type 1 receptor inhibition in the vascular smooth muscle cells or the activation of hyperpolarizing K+ channel. [ABSTRACT FROM AUTHOR]

Mutagenic and antimutagenic activities of lactic acid bacteria (LAB) Lactobacillus plantarum isolated from the local fermented durian (tempoyak) was determined by Ames test (Salmonella/microsome mutagenicity assay). Our study also involved pre-incubation assay against Salmonella typhimurium TA 98 and TA 100 bacterial strain in the presence and absence of metabolic activator S9 system. It was found that the L. plantarum showed no mutagenic activity on both S. typhimurium strain TA 98 and TA 100 in the presence and absence of metabolic activator. Significant antimutagenic activity (p < 0.05) was observed in both cell-free supernatant and bacterial cell suspension of L. plantarum as compared to the mutagenicity induced by 2-Aminoanthracene in the presence of metabolic activator. Meanwhile, in the absence of metabolic activator, only the bacterial cells of L. plantarum showed antimutagenicity acitivity against Sodium Azide and 2-Nitrofluorene. In conclusion, L. plantarum could play a vital role as chemopreventive agent by binding to mutagens and suppressing mutagenesis. Thus, L. plantarum could be consider as a good candidate for functional food development as a supplement product to prevent development of colon cancer. [ABSTRACT FROM AUTHOR]

Drug Metabolizing Enzyme (DME) has been a target of natural chemopreventive agents to inhibit, retard and reverse the process of carcinogenesis. Pterostilbene, an analog to resveratrol has been reported to possess various pharmacological benefits including chemoprevention. In our study, benzo[a]pyrene-induced HT-29 colorectal cell line was used as the DME model. The activity of phase I enzyme CYP1A as determined by the 7-ethoxyresorufin O-deethylation (EROD) assay was found to be inhibited significantly by pterostilbene at 50 µM, 75 µM and 100 µM (p ≤ 0.01, p ≤ 0.05, p ≤ 0.01 respectively) compared to the benzo[a]pyrene treated group. Meanwhile, pterostilbene induced glutathione-S-transferase (GST) activity significantly (p ≤ 0.01) at 50 µM as compared to the untreated. In addition, However, the protein expression of CYP1A1 and GST in pterostilbene treated group was not significantly affected compared to untreated. On the other hand, pterostilbene at 25 and 75 µM were able to increase the protein expression of transcription factor Nrf2 significantly (p ≤ 0.01). Results indicated that pterostilbene could reduce metabolic activation of procarcinogens and increase the detoxification process which can be potentially developed as chemopreventive agent. [ABSTRACT FROM AUTHOR]

Pesticides and chemical fertilizers are widely used in agriculture to increase crop productivity among farmers. However, exposure to pesticides will give potential risk to human health. The aim of this study was to analyze the frequency of micronucleus (MN) and binucleus (BNu) formation in buccal cells from farmers who were exposed to pesticides using the MN assay. Buccal swabs were collected from the farmers in Tanjung Karang (n = 32) and Kelantan (n = 43) using wooden tongue depressor. A structured questionnaire was used to obtain demographic data of the farmers. Cytogenetic analysis was carried out by Acridin Orange (AO) staining 0.0025% (w/v). The frequency of MN and BNu as the biomarkers for cytogenetic damage was observed by using a fluorescence microscope. Comparison of frequency of MN and BNu is conducted in two areas namely Tanjung Karang, Selangor and Kelantan because of the agricultural activity and the type of pesticides used are different. Results showed that the frequencies of both MN and BNu among farmers in Tanjung Karang were significantly higher (p < 0.05) compared to farmers in Kelantan. Meanwhile, for the socio-demographic factors (age, smoking status, working period), MN and BNu frequencies among farmers in Tanjung Karang were also significantly higher (p < 0.05) as compared to farmers in Kelantan. While in the aspect of pesticide exposure, the frequencies of MN and BNu showed no significant difference between the frequency of pesticide spraying (p > 0.05) and the practices of PPE (Personal Protective Equipment) (p > 0.05). This may suggests that cytogenetic changes were not influenced by these factors. In addition, correlation study shows positive correlation between the frequency of MN with the pesticide exposure of farmers in Tanjung Karang (p > 0.05, r = 0.015) and Kelantan (p > 0.05, r = 0.0158). Besides, the frequency of BNu also has a positive correlation with the pesticide exposure among farmers in Tanjung Karang (p > 0.05, r = 0.036) and farmers in Kelantan (p > 0.05, r = 0.013). Hence, this present study demonstrated that exposure to pesticides increased the formation of MN and BNu among farmers and the prolonged use of pesticides may induce genotoxicity and DNA damage to human. [ABSTRACT FROM AUTHOR]

Drug Metabolizing Enzyme (DME) has been a target of natural chemopreventive agents to inhibit, retard and reverse the process of carcinogenesis. Pterostilbene, an analog to resveratrol has been reported to possess various pharmacological benefits including chemoprevention. In our study, benzo[a]pyrene-induced HT-29 colorectal cell line was used as the DME model. The activity of phase I enzyme CYP1A as determined by the 7-ethoxyresorufin O-deethylation (EROD) assay was found to be inhibited significantly by pterostilbene at 50 μM, 75 μM and 100 μM (p ≤ 0.01, p ≤ 0.05, p ≤ 0.01 respectively) compared to the benzo[a]pyrene treated group. Meanwhile, pterostilbene induced glutathione-S-transferase (GST) activity significantly (p ≤ 0.01) at 50 μM as compared to the untreated. In addition, However, the protein expression of CYP1A1 and GST in pterostilbene treated group was not significantly affected compared to untreated. On the other hand, pterostilbene at 25 and 75 μM were able to increase the protein expression of transcription factor Nrf2 significantly (p ≤ 0.01). Results indicated that pterostilbene could reduce metabolic activation of procarcinogens and increase the detoxification process which can be potentially developed as chemopreventive agent. [ABSTRACT FROM AUTHOR]

Pesticides and chemical fertilizers are widely used in agriculture to increase crop productivity among farmers. However, exposure to pesticides will give potential risk to human health. The aim of this study was to analyze the frequency of micronucleus (MN) and binucleus (BNu) formation in buccal cells from farmers who were exposed to pesticides using the MN assay. Buccal swabs were collected from the farmers in Tanjung Karang (n = 32) and Kelantan (n = 43) using wooden tongue depressor. A structured questionnaire was used to obtain demographic data of the farmers. Cytogenetic analysis was carried out by Acridin Orange (AO) staining 0.0025% (w/v). The frequency of MN and BNu as the biomarkers for cytogenetic damage was observed by using a fluorescence microscope. Comparison of frequency of MN and BNu is conducted in two areas namely Tanjung Karang, Selangor and Kelantan because of the agricultural activity and the type of pesticides used are different. Results showed that the frequencies of both MN and BNu among farmers in Tanjung Karang were significantly higher (p < 0.05) compared to farmers in Kelantan. Meanwhile, for the socio-demographic factors (age, smoking status, working period), MN and BNu frequencies among farmers in Tanjung Karang were also significantly higher (p < 0.05) as compared to farmers in Kelantan. While in the aspect of pesticide exposure, the frequencies of MN and BNu showed no significant difference between the frequency of pesticide spraying (p > 0.05) and the practices of PPE (Personal Protective Equipment) (p > 0.05). This may suggests that cytogenetic changes were not influenced by these factors. In addition, correlation study shows positive correlation between the frequency of MN with the pesticide exposure of farmers in Tanjung Karang (p > 0.05, r = 0.015) and Kelantan (p > 0.05, r = 0.0158). Besides, the frequency of BNu also has a positive correlation with the pesticide exposure among farmers in Tanjung Karang (p > 0.05, r = 0.036) and farmers in Kelantan (p > 0.05, r = 0.013). Hence, this present study demonstrated that exposure to pesticides increased the formation of MN and BNu among farmers and the prolonged use of pesticides may induce genotoxicity and DNA damage to human. [ABSTRACT FROM AUTHOR]