Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 May 15;19(5):1466.
doi: 10.3390/ijms19051466.

Cytoprotective Effect of Epigallocatechin Gallate (EGCG)-5'-O-α-Glucopyranoside, a Novel EGCG Derivative

Affiliations
Free PMC article

Cytoprotective Effect of Epigallocatechin Gallate (EGCG)-5'-O-α-Glucopyranoside, a Novel EGCG Derivative

Sang Yun Han et al. Int J Mol Sci. .
Free PMC article

Abstract

Epigallocatechin gallate (EGCG) is a well-studied polyphenol with antioxidant effects. Since EGCG has low solubility and stability, many researchers have modified EGCG residues to ameliorate these problems. A novel EGCG derivative, EGCG-5'-O-α-glucopyranoside (EGCG-5'Glu), was synthesized, and its characteristics were investigated. EGCG-5'Glu showed antioxidant effects in cell and cell-free systems. Under SNP-derived radical exposure, EGCG-5'Glu decreased nitric oxide (NO) production, and recovered ROS-mediated cell viability. Moreover, EGCG-5'Glu regulated apoptotic pathways (caspases) and cell survival molecules (phosphoinositide 3-kinase (PI3K) and phosphoinositide-dependent kinase 1 (PDK1)). In another radical-induced condition, ultraviolet B (UVB) irradiation, EGCG-5'Glu protected cells from UVB and regulated the PI3K/PDK1/AKT pathway. Next, the proliferative effect of EGCG-5'Glu was examined. EGCG-5'Glu increased cell proliferation by modulating nuclear factor (NF)-κB activity. EGCG-5'Glu protects and repairs cells from external damage via its antioxidant effects. These results suggest that EGCG-5'Glu could be used as a cosmetics ingredient or dietary supplement.

Keywords: antioxidant; apoptosis; cell survival; epigallocatechin gallate derivate; free radicals.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Structure of EGCG-5′-O-α-glucopyranoside (EGCG-5′Glu).
Figure 2
Figure 2
Antioxidant effect of EGCG-5′Glu. 250 mM DPPH solution was incubated with EGCG-5′Glu (0–25 μM), ascorbic acid (50 μM) (a, left panel), or EGCG (0–25 μM) (a, right panel) at 37 °C for 30 min. Absorbance at 517 nm was measured by spectrophotometry. Ascorbic acid was used as a positive control. Mixture of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) solution and EGCG-5′Glu (b, left panel) or EGCG (b, right panel) was reacted at 37 °C for 30 min. Scavenging of ABTS was determined by measuring absorbance at 730 nm. Ascorbic acid was used as positive control. (c) DHR123 was treated on RAW264.7 cells for 10 min, and EGCG-5′Glu or ascorbic acid were then added. Cells were incubated with sodium nitroprusside (SNP) for 20 min, and reactive oxygen species (ROS) generation was determined by fluorescence-activated cell sorting (FACS). Ascorbic acid and EGCG were used for a positive control in DPPH assay, ABTS assay, and ROS generation experiment. (d) Cytotoxicity of EGCG-5′Glu on RAW264.7 cells was tested by MTT assay. ## p < 0.01 versus a normal group (untreated group), * p < 0.05 and ** p < 0.01 versus a control group (induced group).
Figure 3
Figure 3
Anti-apoptotic effect of EGCG-5′Glu under SNP-induced apoptosis. (a) EGCG-5′Glu was applied to HaCaT cells for 24 h. Cell viability was tested by MTT assay. (b) EGCG-5′Glu was pre-treated on RAW264.7 cells for 30 min, and SNP (1.5 mM) was added for 24 h. SNP-derived NO was measured by Griess assay. (c) Under SNP treatment, cell viability of HaCaT cells with or without EGCG-5′Glu was identified by MTT assay. (d) Caspase levels of EGCG-5′Glu and SNP-treated HaCaT cells were analyzed by immunoblotting. Antibodies against total or cleaved caspase-3, -8, and -9 and β-actin were used. (e) Phosphorylated levels of PI3K, PDK1, and AKT in EGCG-5′Glu- and SNP-treated HaCaT cells were analyzed by immunoblotting. Antibodies against phospho- or total forms PI3K, PDK1, AKT, and β-actin were used. # p < 0.05 and ## p < 0.01 versus a normal group (untreated group), * p < 0.05 and ** p < 0.01 versus a control group (SNP-treated group).
Figure 4
Figure 4
Anti-oxidant effect of EGCG-5′Glu against UVB-induced damage. (a) Images of HaCaT cells treated with EGCG-5′Glu (0–25 μM) and UVB (30 mJ/cm2) irradiation for 48 h were captured with a camera attached to the microscope. (b) Under UVB irradiation, viability of HaCaT cells with and without EGCG-5′Glu was measured by MTT assay. (c) Under UVB irradiation, HaCaT cell were incubated with EGCG-5′Glu for 48 h. Phospho- and total PI3K, AKT, and PDK1 expression was detected by immunoblotting. β-Actin was used as an immunoblotting loading control. ** p < 0.01 versus a control group (UVB-treated group).
Figure 4
Figure 4
Anti-oxidant effect of EGCG-5′Glu against UVB-induced damage. (a) Images of HaCaT cells treated with EGCG-5′Glu (0–25 μM) and UVB (30 mJ/cm2) irradiation for 48 h were captured with a camera attached to the microscope. (b) Under UVB irradiation, viability of HaCaT cells with and without EGCG-5′Glu was measured by MTT assay. (c) Under UVB irradiation, HaCaT cell were incubated with EGCG-5′Glu for 48 h. Phospho- and total PI3K, AKT, and PDK1 expression was detected by immunoblotting. β-Actin was used as an immunoblotting loading control. ** p < 0.01 versus a control group (UVB-treated group).
Figure 5
Figure 5
Effect of EGCG-5′Glu on cell proliferation. (a) Proliferation of HaCaT cells treated with EGCG-5′Glu (0–25 μM) for 0–48 h was measured by MTT assay (left panel) and by Trypan blue dye exclusion assay. (b) HEK293 cells were transfected with NF-κB-Luc (left panel), AP-1-Luc (right panel), and β-gal plasmids and treated with EGCG-5′Glu (0-25 μM) for 24 h. (c) Levels of phospho- and total forms of p65 and p50 (left panel) and c-Jun and c-Fos (right panel) in whole cell lysates were determined by immunoblot analysis after treating HaCaT cells with EGCG-5′Glu (0–25 μM) for 48 h. (d, left panel) Viability of Bay11-7082-treated HaCaT cells was measured by MTT assay for 48 h. (d, right panel) Bay11-7082 (5 μM) was treated with or without EGCG-5′Glu (25 μM), and viability of HaCaT cells was measured by MTT assay. (e) With EGCG-5′Glu (25 μM) treatment, the effect of NF-κB on cell proliferation using Bay11-7082 (5 μM) was confirmed by MTT assay. * p < 0.05 and ** p < 0.01 versus a control group (normal group).
Figure 5
Figure 5
Effect of EGCG-5′Glu on cell proliferation. (a) Proliferation of HaCaT cells treated with EGCG-5′Glu (0–25 μM) for 0–48 h was measured by MTT assay (left panel) and by Trypan blue dye exclusion assay. (b) HEK293 cells were transfected with NF-κB-Luc (left panel), AP-1-Luc (right panel), and β-gal plasmids and treated with EGCG-5′Glu (0-25 μM) for 24 h. (c) Levels of phospho- and total forms of p65 and p50 (left panel) and c-Jun and c-Fos (right panel) in whole cell lysates were determined by immunoblot analysis after treating HaCaT cells with EGCG-5′Glu (0–25 μM) for 48 h. (d, left panel) Viability of Bay11-7082-treated HaCaT cells was measured by MTT assay for 48 h. (d, right panel) Bay11-7082 (5 μM) was treated with or without EGCG-5′Glu (25 μM), and viability of HaCaT cells was measured by MTT assay. (e) With EGCG-5′Glu (25 μM) treatment, the effect of NF-κB on cell proliferation using Bay11-7082 (5 μM) was confirmed by MTT assay. * p < 0.05 and ** p < 0.01 versus a control group (normal group).
Figure 6
Figure 6
Summary of the cytoprotective effect of EGCG-5′Glu. EGCG-5′Glu cleared various free radicals and downregulated caspase activities. Survival signal pathway (PI3K/AKT/NF-κB) improved with EGCG-5′Glu, and cell proliferation increased. → stimulation, ⊥ inhibition.

Similar articles

See all similar articles

Cited by 2 articles

References

    1. Pandel R., Poljšak B., Godic A., Dahmane R. Skin photoaging and the role of antioxidants in its prevention. ISRN Dermatol. 2013;2013:930164. doi: 10.1155/2013/930164. - DOI - PMC - PubMed
    1. Poljšak B., Dahmane R. Free radicals and extrinsic skin aging. Dermatol. Res. Pract. 2012;2012:135206. doi: 10.1155/2012/135206. - DOI - PMC - PubMed
    1. Circu M.L., Aw T.Y. Reactive oxygen species, cellular redox systems, and apoptosis. Free Radic. Biol. Med. 2010;48:749–762. doi: 10.1016/j.freeradbiomed.2009.12.022. - DOI - PMC - PubMed
    1. Kang S.W. Role of reactive oxygen species in cell death pathways. Hanyang Med. Rev. 2013;33:77–82. doi: 10.7599/hmr.2013.33.2.77. - DOI
    1. Kamogashira T., Fujimoto C., Yamasoba T. Reactive oxygen species, apoptosis, and mitochondrial dysfunction in hearing loss. BioMed Res. Int. 2015;2015:617207. doi: 10.1155/2015/617207. - DOI - PMC - PubMed

MeSH terms

Feedback