Publications by authors named "Siupo Ip"

5 Publications

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Apoptotic activities of brusatol in human non-small cell lung cancer cells: Involvement of ROS-mediated mitochondrial-dependent pathway and inhibition of Nrf2-mediated antioxidant response.

Toxicology 2021 03 16;451:152680. Epub 2021 Jan 16.

Guangdong Provincial Key Laboratory of Clinical Research on Traditional Chinese Medicine Syndrome, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510120, P.R. China; The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510120, P.R. China; State Key Laboratory of Dampness Syndrome of Chinese Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou 510120, P.R. China.

Brusatol occurs as a characteristic bioactive principle of Brucea javanica (L.) Merr., a traditional medicinal herb frequently employed to tackle cancer in China. This work endeavored to unravel the potential anti-cancer activity and action mechanism of brusatol against non-small cell lung cancer (NSCLC) cell lines. The findings indicated that brusatol remarkably inhibited the growth of wild-type NSCLC cell lines (A549 and H1650) and epidermal growth factor receptor-mutant cell lines (PC9 and HCC827) in a dose- and time-related fashion, and profoundly inhibited the clonogenic capability and migratory capacity of PC9 cells. Treatment with brusatol resulted in significant apoptosis in PC9 cells, as evidenced by Hoechst 33342 staining and flow cytometric analysis. The apoptotic effect was closely related to induction of G0-G1 cell cycle arrest, stimulation of reactive oxygen species (ROS) and malondialdehyde, decrease of glutathione levels and disruption of mitochondrial membrane potential. Furthermore, pretreatment with N-acetylcysteine, a typical ROS scavenger, markedly ameliorated the brusatol-induced inhibition of PC9 cells. Western blotting assay indicated that brusatol pronouncedly suppressed the expression levels of mitochondrial apoptotic pathway-associated proteins Bcl-2 and Bcl-xl, accentuated the expression of Bax and Bak, and upregulated the protein expression of XIAP, cleaved caspase-3/pro caspase-3, cleaved caspase-8/pro caspase-8, and cleaved PARP/total PARP. In addition, brusatol significantly suppressed the expression of Nrf2 and HO-1, and abrogated tBHQ-induced Nrf2 activation. Combinational administration of brusatol with four chemotherapeutic agents exhibited marked synergetic effect on PC9 cells. Together, the inhibition of PC9 cells proliferation by brusatol might be intimately associated with the modulation of ROS-mediated mitochondrial-dependent pathway and inhibition of Nrf2-mediated antioxidant response. This novel insight might provide further evidence to buttress the antineoplastic efficacy of B. javanica, and support a role for brusatol as a promising anti-cancer candidate or adjuvant to current chemotherapeutic medication in the therapy of EGFR-mutant NSCLC.
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http://dx.doi.org/10.1016/j.tox.2021.152680DOI Listing
March 2021

(-)-Patchouli alcohol protects against Helicobacter pylori urease-induced apoptosis, oxidative stress and inflammatory response in human gastric epithelial cells.

Int Immunopharmacol 2016 Jun 24;35:43-52. Epub 2016 Mar 24.

School of Chinese Materia Medica, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China; Dongguan Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Dongguan 523808, ,PR China. Electronic address:

(-)-Patchouli alcohol (PA), the major active principle of Pogostemonis Herba, has been reported to have anti-Helicobacter pylori and gastroprotective effects. In the present work, we aimed to investigate the possible protective effect of PA on H. pylori urease (HPU)-injured human gastric epithelial cells (GES-1) and to elucidate the underlying mechanisms of action. Results showed that pre-treatment with PA (5.0, 10.0, 20.0μM) was able to remarkably ameliorate the cytotoxicity induced by 17.0U/mg HPU in GES-1 cells. Flow cytometric analysis on cellular apoptosis showed that pre-treatment with PA effectively attenuated GES-1 cells from the HPU-induced apoptosis. Moreover, the cytoprotective effect of PA was found to be associated with amelioration of the HPU-induced disruption of MMP, attenuating oxidative stress by decreasing contents of intracellular ROS and MDA, and increasing superoxide dismutase (SOD) and catalase (CAT) enzymatic activities. In addition, pre-treatment with PA markedly attenuated the secretion of nitric oxide (NO) and pro-inflammatory cytokines such as interleukin-2 (IL-2), interleukin-4 (IL-4) and tumor necrosis factor-α (TNF-α), whereas elevated the anti-inflammatory cytokine interleukin-13 (IL-13) in the HPU-stimulated GES-1 cells. Molecular docking assay suggested that PA engaged in the active site of urease bearing nickel ions and interacted with important residues via covalent binding, thereby restricting the active urease catalysis conformation. Our experimental findings suggest that PA could inhibit the cellular processes critically involved in the pathogenesis of H. pylori infection, and its protective effects against the HPU-induced cytotoxicity in GES-1 cells are believed to be associated with its anti-apoptotic, antioxidative, anti-inflammatory and HPU inhibitory actions.
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http://dx.doi.org/10.1016/j.intimp.2016.02.022DOI Listing
June 2016

Sonodynamic action of curcumin on foodborne bacteria Bacillus cereus and Escherichia coli.

Ultrasonics 2015 Sep 21;62:75-9. Epub 2015 May 21.

School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China. Electronic address:

Bacterial contamination is an important cause of foodborne diseases. The present study aimed to investigate sonodynamic action of curcumin on foodborne bacteria Bacillus cereus (B. cereus) and Escherichia coli (E. coli). The uptake of curcumin was measured for optimizing the concentration incubation time before ultrasound sonication, and colony forming units (CFU) were counted after ultrasound treatment. The chromosomal DNA fragmentation of bacteria was analyzed and the effect of hypoxic condition on the antibacterial efficacy of sonodynamic action of curcumin was also assessed in this study. The results showed that the maximum uptake of curcumin in B. cereus and E. coli occurred in 50min after curcumin incubation. Curcumin had sonodynamic bactericidal activity in a curcumin dose-dependent manner, and 5.6-log reduction in CFU of B. cereus was observed after curcumin treatment (2.0μM), however, only 2-log reduction in CFU of E. coli after 40μM curcumin treatment. No significant change in chromosomal DNA was found after the combined treatment of curcumin and ultrasound. The survival of B. cereus and E. coli after sonodynamic treatment in hypoxic group was significantly higher than that in normal oxygen group. These findings indicated that sonodynamic action of curcumin had significant inactivation effect on foodborne bacteria, and B. cereus was more sensitive to sonodynamic treatment of curcumin than E. coli. Sonodynamic antibacterial activity of curcumin might be dependent on the oxygen environment.
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http://dx.doi.org/10.1016/j.ultras.2015.05.003DOI Listing
September 2015

Analgesic effect of Coptis chinensis rhizomes (Coptidis Rhizoma) extract on rat model of irritable bowel syndrome.

J Ethnopharmacol 2011 Jun 12;135(3):754-61. Epub 2011 Apr 12.

School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong.

Ethnopharmacological Relevance: Coptis chinensis rhizomes (Coptidis Rhizoma, CR), also known as "Huang Lian", is a common component of traditional Chinese herbal formulae used for the relief of abdominal pain and diarrhea. Yet, the action mechanism of CR extract in the treatment of irritable bowel syndrome is unknown. Thus, the aim of our present study is to investigate the effect of CR extract on neonatal maternal separation (NMS)-induced visceral hyperalgesia in rats and its underlying action mechanisms.

Materials And Methods: Male Sprague-Dawley rats were subjected to 3-h daily maternal separation from postnatal day 2 to day 21 to form the NMS group. The control group consists of unseparated normal (N) rats. From day 60, rats were administrated CR (0.3, 0.8 and 1.3 g/kg) or vehicle (Veh; 0.5% carboxymethylcellulose solution) orally for 7 days for the test and control groups, respectively.

Results: Electromyogram (EMG) signals in response to colonic distension were measured with the NMS rats showing lower pain threshold and increased EMG activity than those of the unseparated (N) rats. CR dose-dependently increased pain threshold response and attenuated EMG activity in the NMS rats. An enzymatic immunoassay study showed that CR treatment significantly reduced the serotonin (5HT) concentration from the distal colon of NMS rats compared to the Veh (control) group. Real-time quantitative PCR and Western-blotting studies showed that CR treatment substantially reduced NMS induced cholecystokinin (CCK) expression compared with the Veh group.

Conclusions: These results suggest that CR extract robustly reduces visceral pain that may be mediated via the mechanism of decreasing 5HT release and CCK expression in the distal colon of rats.
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http://dx.doi.org/10.1016/j.jep.2011.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3100428PMC
June 2011

Antidepressant-like effect of ethanol extract from Paeonia lactiflora in mice.

Phytother Res 2008 Nov;22(11):1496-9

School of Chinese Medicine, the Chinese University of Hong Kong, Shatin, N.T., Hong Kong.

The present study investigated the antidepressant effect of ethanol extract of Paeonia lactiflora (EPL) in mice using forced swim test, tail suspension test, open-field test and reserpine test. Our results showed that intragastric administration of EPL at the doses of 250 and 500 mg/kg for seven days significantly reduced the duration of immobility in both forced swim test and tail suspension test. EPL at the dose of 500 mg/kg was as effective as the positive control (chlorimipramine, 20 mg/kg) in these tests. However, these treatments did not affect the number of crossing and rearing in the open-field test. Treating mice with EPL at the doses of 250 and 500 mg/kg significantly antagonized reserpine-induced ptosis and hypothermia. However, at the dose of 125 mg/kg, EPL antagonized only the hypothermia but not ptosis induced by reserpine. The results clearly demonstrated the antidepressant effect of Paeonia lactiflora in animal models of depression. The action of Paeonia lactiflora may be mediated via the central monoaminergic neurotransmitter system.
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http://dx.doi.org/10.1002/ptr.2519DOI Listing
November 2008
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