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Antioxidant biomarkers from Vanda coerulea stems reduce irradiated HaCaT PGE-2 production as a result of COX-2 inhibition.

Simmler C, Antheaume C, Lobstein A - PLoS ONE (2010)

Bottom Line: Dihydro-phenanthropyran (1) and dihydro-phenanthrene (2) displayed the best DPPH/(•)OH radical scavenging activities as well as HaCaT intracellular antioxidant properties (using DCFH-DA probe: IC(50) 8.8 µM and 9.4 µM, respectively) compared to bibenzyle (3) (IC(50) 20.6 µM).Major antioxidant stilbenoids (1-3) from Vanda coerulea stems displayed an inhibition of UV(B)-induced COX-2 expression.Imbricatin (1) and methoxycoelonin (2) were also able to inhibit COX-2 activity in a concentration-dependent manner thereby reducing PGE-2 production from irradiated HaCaT cells.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy, University of Strasbourg, Illkirch, France. charlotte.simmler@pharma.u-strasbg.fr

ABSTRACT

Background: In our investigations towards the isolation of potentially biologically active constituents from Orchidaceae, we carried out phytochemical and biological analyses of Vanda species. A preliminary biological screening revealed that Vanda coerulea (Griff. ex. Lindl) crude hydro-alcoholic stem extract displayed the best DPPH /(•)OH radical scavenging activity and in vitro inhibition of type 2 prostaglandin (PGE-2) release from UV(B) (60 mJ/cm(2)) irradiated HaCaT keratinocytes.

Principal findings: Bio-guided fractionation and phytochemical analysis led to the isolation of five stilbenoids: imbricatin (1) methoxycoelonin (2) gigantol (3) flavidin (4) and coelonin (5). Stilbenoids (1-3) were the most concentrated in crude hydro-alcoholic stem extract and were considered as Vanda coerulea stem biomarkers. Dihydro-phenanthropyran (1) and dihydro-phenanthrene (2) displayed the best DPPH/(•)OH radical scavenging activities as well as HaCaT intracellular antioxidant properties (using DCFH-DA probe: IC(50) 8.8 µM and 9.4 µM, respectively) compared to bibenzyle (3) (IC(50) 20.6 µM). In turn, the latter showed a constant inhibition of PGE-2 production, stronger than stilbenoids (1) and (2) (IC(50) 12.2 µM and 19.3 µM, respectively). Western blot analysis revealed that stilbenoids (1-3) inhibited COX-2 expression at 23 µM. Interestingly, stilbenoids (1) and (2) but not (3) were able to inhibit human recombinant COX-2 activity.

Conclusions: Major antioxidant stilbenoids (1-3) from Vanda coerulea stems displayed an inhibition of UV(B)-induced COX-2 expression. Imbricatin (1) and methoxycoelonin (2) were also able to inhibit COX-2 activity in a concentration-dependent manner thereby reducing PGE-2 production from irradiated HaCaT cells. Our studies suggest that stilbenoids (1-3) could be potentially used for skin protection against the damage caused by UV(B) exposure.

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Reactive Oxygen Species (ROS) neutralization in H2O2 stressed HaCaT cells by stilbenoids 1–3.Results are expressed as percentages of total ROS neutralization in HaCaT cells calculated by comparison with the positive control (H2O2 stressed cell). Intracellular antioxidant properties of stilbenoids 1–3, considered as stem biomarkers, were evaluated on intracellular ROS neutralization. IC50 were calculated with more points than those represented on the graph. α-Tocopherol at 25 µM was used as a positive reference. (*) set at p<0.05, gigantol (3) effect was statistically different from those of imbricatin (1) and methoxycoelonin (2).
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pone-0013713-g003: Reactive Oxygen Species (ROS) neutralization in H2O2 stressed HaCaT cells by stilbenoids 1–3.Results are expressed as percentages of total ROS neutralization in HaCaT cells calculated by comparison with the positive control (H2O2 stressed cell). Intracellular antioxidant properties of stilbenoids 1–3, considered as stem biomarkers, were evaluated on intracellular ROS neutralization. IC50 were calculated with more points than those represented on the graph. α-Tocopherol at 25 µM was used as a positive reference. (*) set at p<0.05, gigantol (3) effect was statistically different from those of imbricatin (1) and methoxycoelonin (2).

Mentions: The probe 2′,7′-dichlorofluorescin is used as an indicator of ROS formation in H2O2 (100 µM) stressed HaCaT. The intracellular fluorescence measurement using this probe mainly reflects the ability of stilbenoids to inhibit intracellular •OH radical [37]. In this assay, we have compared the ROS scavenging activities of stem biomarkers. According to our previous cell viability analyses, the first higher concentration tested on HaCaT cells was not cytotoxic. Imbricatin (1) (IC50 8.8 µM) and methoxycoelonin (2) (IC50 9.4 µM) showed better ROS neutralization than gigantol (3) (IC50 20.6 µM) and even than quercetin (IC50 13.8 µM). (Figure 3, Table 2) These results were in accordance with our results obtained previously on •OH radicals, with chemiluminescence. Consequently, we have demonstrated the intracellular ROS scavenging activities of these three stilbenoids on immortalized keratinocytes. Best intracellular antioxidant activities were obtained with the dihydro-phenanthropyran (1) and the dihydro-phenanthrene (2).


Antioxidant biomarkers from Vanda coerulea stems reduce irradiated HaCaT PGE-2 production as a result of COX-2 inhibition.

Simmler C, Antheaume C, Lobstein A - PLoS ONE (2010)

Reactive Oxygen Species (ROS) neutralization in H2O2 stressed HaCaT cells by stilbenoids 1–3.Results are expressed as percentages of total ROS neutralization in HaCaT cells calculated by comparison with the positive control (H2O2 stressed cell). Intracellular antioxidant properties of stilbenoids 1–3, considered as stem biomarkers, were evaluated on intracellular ROS neutralization. IC50 were calculated with more points than those represented on the graph. α-Tocopherol at 25 µM was used as a positive reference. (*) set at p<0.05, gigantol (3) effect was statistically different from those of imbricatin (1) and methoxycoelonin (2).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2965657&req=5

pone-0013713-g003: Reactive Oxygen Species (ROS) neutralization in H2O2 stressed HaCaT cells by stilbenoids 1–3.Results are expressed as percentages of total ROS neutralization in HaCaT cells calculated by comparison with the positive control (H2O2 stressed cell). Intracellular antioxidant properties of stilbenoids 1–3, considered as stem biomarkers, were evaluated on intracellular ROS neutralization. IC50 were calculated with more points than those represented on the graph. α-Tocopherol at 25 µM was used as a positive reference. (*) set at p<0.05, gigantol (3) effect was statistically different from those of imbricatin (1) and methoxycoelonin (2).
Mentions: The probe 2′,7′-dichlorofluorescin is used as an indicator of ROS formation in H2O2 (100 µM) stressed HaCaT. The intracellular fluorescence measurement using this probe mainly reflects the ability of stilbenoids to inhibit intracellular •OH radical [37]. In this assay, we have compared the ROS scavenging activities of stem biomarkers. According to our previous cell viability analyses, the first higher concentration tested on HaCaT cells was not cytotoxic. Imbricatin (1) (IC50 8.8 µM) and methoxycoelonin (2) (IC50 9.4 µM) showed better ROS neutralization than gigantol (3) (IC50 20.6 µM) and even than quercetin (IC50 13.8 µM). (Figure 3, Table 2) These results were in accordance with our results obtained previously on •OH radicals, with chemiluminescence. Consequently, we have demonstrated the intracellular ROS scavenging activities of these three stilbenoids on immortalized keratinocytes. Best intracellular antioxidant activities were obtained with the dihydro-phenanthropyran (1) and the dihydro-phenanthrene (2).

Bottom Line: Dihydro-phenanthropyran (1) and dihydro-phenanthrene (2) displayed the best DPPH/(•)OH radical scavenging activities as well as HaCaT intracellular antioxidant properties (using DCFH-DA probe: IC(50) 8.8 µM and 9.4 µM, respectively) compared to bibenzyle (3) (IC(50) 20.6 µM).Major antioxidant stilbenoids (1-3) from Vanda coerulea stems displayed an inhibition of UV(B)-induced COX-2 expression.Imbricatin (1) and methoxycoelonin (2) were also able to inhibit COX-2 activity in a concentration-dependent manner thereby reducing PGE-2 production from irradiated HaCaT cells.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Pharmacy, University of Strasbourg, Illkirch, France. charlotte.simmler@pharma.u-strasbg.fr

ABSTRACT

Background: In our investigations towards the isolation of potentially biologically active constituents from Orchidaceae, we carried out phytochemical and biological analyses of Vanda species. A preliminary biological screening revealed that Vanda coerulea (Griff. ex. Lindl) crude hydro-alcoholic stem extract displayed the best DPPH /(•)OH radical scavenging activity and in vitro inhibition of type 2 prostaglandin (PGE-2) release from UV(B) (60 mJ/cm(2)) irradiated HaCaT keratinocytes.

Principal findings: Bio-guided fractionation and phytochemical analysis led to the isolation of five stilbenoids: imbricatin (1) methoxycoelonin (2) gigantol (3) flavidin (4) and coelonin (5). Stilbenoids (1-3) were the most concentrated in crude hydro-alcoholic stem extract and were considered as Vanda coerulea stem biomarkers. Dihydro-phenanthropyran (1) and dihydro-phenanthrene (2) displayed the best DPPH/(•)OH radical scavenging activities as well as HaCaT intracellular antioxidant properties (using DCFH-DA probe: IC(50) 8.8 µM and 9.4 µM, respectively) compared to bibenzyle (3) (IC(50) 20.6 µM). In turn, the latter showed a constant inhibition of PGE-2 production, stronger than stilbenoids (1) and (2) (IC(50) 12.2 µM and 19.3 µM, respectively). Western blot analysis revealed that stilbenoids (1-3) inhibited COX-2 expression at 23 µM. Interestingly, stilbenoids (1) and (2) but not (3) were able to inhibit human recombinant COX-2 activity.

Conclusions: Major antioxidant stilbenoids (1-3) from Vanda coerulea stems displayed an inhibition of UV(B)-induced COX-2 expression. Imbricatin (1) and methoxycoelonin (2) were also able to inhibit COX-2 activity in a concentration-dependent manner thereby reducing PGE-2 production from irradiated HaCaT cells. Our studies suggest that stilbenoids (1-3) could be potentially used for skin protection against the damage caused by UV(B) exposure.

Show MeSH
Related in: MedlinePlus