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The In Vitro Antioxidant Properties of Chinese Highland Lichens
( Heng Luo ),( Yoshikazu Yamamoto ),( Yan Peng Liu ),( Jae Sung Jung ),( Hyung Yeel Kahng ),( Young Jin Koh ),( Jae Seoun Hur ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.11
The antioxidant properties of 46 lichen species, collected from the highly UV-exposed alpine areas of southwestern China, were evaluated for their potential therapeutic utilization. The anti-linoleic acid peroxidation activity, 1,1- diphenyl-2-picryl-hydrazyl (DPPH) scavenging activity, reducing power, and total phenolic contents were all assessed in vitro in the methanol extract of the lichens. A potent reducing power was detected in a number of the lichen extracts, when compared with butylated hydroxyanisole (BHA). In general, it was found that many of the lichens, with antioxidant properties, contained large quantities of phenolic content. Extracts of Peltigera praetextata and Sticta nylanderiana were found to exhibit the most potent activity in all of the antioxidant tests. In particular, extracts of S. nylanderiana displayed a 1.37 times greater anti-linoleic acid peroxidation activity, when compared with the ascorbic acid used as the positive control. S. nylanderiana also possessed the strongest free radical scavenging activity amongst all the tested species, with an inhibition rate of 90.4% at concentration of 330 ?g/ml. Activity-guided bioautographic TLC and HPLC analyses were used to establish which compounds were responsible for the potent antioxidant activities of the S. nylanderiana extract. These analyses revealed lecanoric acid to be primarily responsible for the effective antioxidant properties of S. nylanderiana. Overall, these results have indicated that several highland lichens have the potential of being utilized as novel bioresources for naturally occurring antioxidant therapies.
Luo, Guo-Xuan,Cai, Jun,Lin, Jing-Zhi,Luo, Wei-Shi,Luo, Heng-Shan,Jiang, Yu-Yang,Zhang, Yong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12
Objective: To investigate the effects of gambogic acid (GA) on the growth of human malignant glioma cells. Methods: U251MG and U87MG human glioma cell lines were treated with GA and growth and proliferation were investigated by MTT and colony formation assays. Cell apoptosis was analyzed by annexin V FITC/PI flow cytometry, mitochondrial membrane potential assays and DAPI nuclear staining. Monodansylcadaverine (MDC) staining and GFP-LC3 localisation were used to detect autophagy. Western blotting was used to investigate the molecular changes that occurred in the course of GA treatment. Results: GA treatment significantly suppressed cell proliferation and colony formation, induced apoptosis in U251 and U87MG glioblastoma cells in a time- and dose-dependent manner. GA treatment also lead to the accumulation of monodansylcadaverine (MDC) in autophagic vacuoles, upregulated expressions of Atg5, Beclin 1 and LC3-II, and the increase of punctate fluorescent signals in glioblastoma cells pre-transfected with GFP-tagged LC3 plasmid. After the combination treatment of autophagy inhitors and GA, GA mediated growth inhibition and apoptotic cell death was further potentiated. Conclusion: Our results suggested that autophagic responses play roles as a self-protective mechanism in GA-treated glioblastoma cells, and autophagy inhibition could be a novel adjunctive strategy for enhancing chemotherapeutic effect of GA as an anti-malignant glioma agent.
Heng Luo,Yoshikazu Yamamoto,Hae-Sook Jeon,Yan Peng Liu,Jae Sung Jung,Young Jin Koh,허재선 한국미생물학회 2011 The journal of microbiology Vol.49 No.1
The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF. The extract of Nephromopsis pallescens (KOLRI-040516) exhibited the strongest anti-H. pylori activity. Bioautograghic TLC and HPLC analysis identified usnic acid as the main antibacterial substance produced by N. pallescens. The growth of N. pallescens and production of antibacterial substances produced by the fungus were then investigated under several culture conditions including the culture media, initial medium pHs, incubation temperatures, and the degree of aeration. The results indicated that culture in MY medium with an initial pH of 6.0, a temperature of 15°C and a low degree of aeration supported the largest usnic acid production of the fungus (16.4 μg usnic acid/g dry biomass). Especially, aeration was found to be an important factor that affect both growth and usnic acid production of N. pallescens.
( Luo Heng ),( Chang Tian Li ),( Jin Cheol Kim ),( Yan Peng Liu ),( Jae Sung Jung ),( Young Jin Koh ),( Jae Seoun Hur ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.2
At present, acetylcholinesterase (AChE) inhibitors are the first group of drugs to treat mild to moderate Alzheimer`s disease (AD). Although beneficial in improving cognitive and behavioral symptoms, the effectiveness of AChE inhibitors has been questioned since they do not delay or prevent neurodegeneration in AD patients. Therefore, in the present study, in order to develop new and effective anti-AD agents from lichen products, both the AChE inhibitory and the neuroprotective effects were evaluated. The AChE inhibitory assay was performed based on Ellman`s reaction, and the neuroprotective effect was evaluated by using the MTT method on injured PC12 cells. One AChE inhibitor (IC50 = 27.1 μg/ml) was isolated by means of bioactivity-guided isolation from the extract of lichen-forming fungus Cladonia macilenta, which showed the most potent AChE inhibitory activity in previous screening experiment. It was then identified as biruloquinone by MS, and 1H- and 13C-NMR analyses. The inhibitory kinetic assay suggested that biruloquinone is a mixed-II inhibitor on AChE. Meanwhile, biruloquinone improved the viability of the H2O2- and β-amyloid-injured PC12 cells at 1 to 25 μg/ml. The protective effects are proposed to be related to the potent antioxidant activities of biruloquinone. These results imply that biruloquinone has the potential to be developed as a multifunctional anti- AD agent.
ST6GALNAC1 promotes the invasion and migration of breast cancer cells via the EMT pathway
Luo Yunzhao,Cao Heng,Lei Chuqi,Liu Jun 한국유전학회 2023 Genes & Genomics Vol.45 No.11
Background A specific sialyl-transferases called ST6GALNAC1 has been proven to up-regulate abnormal O‐glycosylation, which is strongly associated with tumorigenesis and cancer progression. However, the precise pathological outcome of ST6GALNAC1 expression in breast cancer cells remains unknown. Therefore, our study aims to investigate the functional role of ST6GALNAC1 and its impact on the epithelial-mesenchymal transition (EMT) pathway in breast cancer cells. Methods Plasmids with siRNA were used to construct ST6GALNAC1 knockoff (si-ST6GALNAC1) MDA-MB-231 and MDA-MB-453 cells, while lentiviruses were used to construct ST6GALNAC1 over-expression (oe-ST6GALNAC1) MCF-7 and BT474 cells. Transfer efficiency was verified by Western Blot. Then we selected transfected cells and assessed the changes in cell proliferation, invasion, migration, and EMT markers. Results The expression of ST6GALNAC1 significantly enhanced cell migration and invasion, which was confirmed by Wound Scratch Assay and Transwell Assay. Particularly, ST6GALNAC1 expression directly induced the EMT signaling pathway. E-cadherin was markedly decreased in oe-ST6GALNAC1 cells, accompanied by an up-regulation of mesenchymal markers including N-cadherin, snail, and ZEB1. However, no significant correlation was found between ST6GALNAC1 expression and cell proliferation. All of the outcomes were reversely validated in si-ST6GALNAC1 cells. Conclusions The expression of ST6GALNAC1 promotes cell migration and invasion probably by triggering the molecular process of the EMT pathway in breast cancer cells, which may provide new clues for designing novel molecular targeted drugs in breast cancer treatment.
Luo, Hao,Li, Zheng,Qing, Yi,Zhang, Shi-Heng,Peng, Yu,Li, Qing,Wang, Dong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.3
Altered DNA repair capacity can result in increased susceptibility to cancer. The base excision repair (BER) pathway effectively removes DNA damage caused by ionizing radiation and reactive oxidative species (ROS). In the current study, we analyzed the possible relation of polymorphisms in BER genes, including 8-oxoguanine DNA glycosylase (OGG1), apurinic/apyrimidinic endonuclease 1 (APE1), and X-ray repair cross-complementing group 1 protein (XRCC1), with breast cancer risk in Chinese Han women. This case-control study examined 194 patients with breast cancer and 245 cancer-free hospitalized control subjects. Single nucleotide polymorphisms (SNPs) of OGG1 (Ser326Cys), XRCC1 (Arg399Gln), and APE1 (Asp148Glu and -141T/G) were genotyped and analyzed for their association with breast cancer risk using multivariate logistic regression models. We found that XRCC1 Arg399Gln was significantly associated with an increased risk of breast cancer. Similarly, the XRCC1 Gln allele was significantly associated with an elevated risk in postmenopausal women and women with a high BMI (${\geq}24kg/m^2$). The OGG1 Cys allele provided a significant protective effect against developing cancer in women with a low BMI (< $24kg/m^2$). When analyzing the combined effects of these alleles on the risk of breast cancer, we found that individuals with ${\geq}2$ adverse genotypes (XRCC1 399Gln, APE1 148Asp, and OGG1 326Ser) were at a 2.18-fold increased risk of breast cancer (P = 0.027). In conclusion, our data indicate that Chinese women with the 399Gln allele of XRCC1 have an increased risk of breast cancer, and the combined effects of polymorphisms of BER genes may contribute to tumorigenesis.
SELF-TUNING OCCUPANT INJURY PREDICTION ALGORITHM FOR ADVANCED AUTOMATIC CRASH NOTIFICATION SYSTEM
Ying Luo,Yuezhou Yin,Heng Wei,Na Chen 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4
In this study, the effect of discrimination threshold on velocity variation is investigated, and a self-tuning algorithm for velocity variation is proposed to improve the accuracy of an advanced automatic crash notification (AACN) system. First, after determining the factors affecting driver injury, an injury prediction model for the driver is developed. Second, the prediction accuracy affected by the discrimination threshold in the AACN system is analyzed using a finite element model for a sled crash test. Third, the self-tuning occupant injury prediction algorithm is presented based on an association model for the velocity variation error, discrimination threshold, and acceleration peak. Fourth, a vehicle terminal is designed by embedding a self-tuning algorithm into the system. Finally, a sled test and vehicle crash test are conducted to verify the reliability of the self-tuning algorithm. The test results show that the self-tuning algorithm can increase the accuracy of the probability of driver injury.