Ixora parviflora Protects against UVB-Induced Photoaging by Inhibiting the Expression of MMPs, MAP Kinases, and COX-2 and by Promoting Type I Procollagen Synthesis

Abstract

Ixora parviflora with high polyphenol content exhibited antioxidant activity and reducing UVB-induced intracellular reactive oxygen species production. In this study, results of the photoaging screening experiments revealed that IPE at 1000 μg/mL reduced the activity of bacterial collagenase by 92.7 ± 4.2% and reduced the activity of elastase by 32.6 ± 1.4%. Therefore, we investigated the mechanisms by which IPE exerts its anti-photoaging activity. IPE at 1 μg/mL led to an increase in type I procollagen expression and increased total collagen synthesis in fibroblasts at 5 μg/mL. We found that IPE inhibited MMP-1, MMP-3, and MMP-9 expression at doses of 1, 5, and 10 μg/mL, respectively, in fibroblasts exposed to UV irradiation (40 mJ/cm(2)). Gelatin zymography assay showed that IPE at 50 μg/mL inhibited MMP-9 secretion/activity in cultured fibroblasts after UVB exposure. In addition, IPE inhibited the phosphorylation of p38, ERK, and JNK induced by UVB. Furthermore, IPE inhibited the UVB-induced expression of Smad7. In addition, IPE at 1 μg/mL inhibited NO production and COX-2 expression in UV-exposed fibroblasts. These findings show that IPE exhibits anti-inflammatory and anti-photoaging activities, indicating that IPE could be a potential anti-aging agent.

Figure 1

The inhibition of Ixora parviflora extract and its hydrolysates on collagenase activity (a, b) and bacterial collagenase activity by fluorometric assay (c). DC: doxycycline; PG: propylene glycol; IPH1: 85°C, 1.2 N HCl; IPH2: 85°C, 2.4 N HCl; IPH3: 100°C, 1.2 N HCl; IPH4: 100°C, 2.4 N HCl. (n = 4; **P < 0.01; ***P < 0.001).

Figure 2

The inhibition of Ixora parviflora extract on elastase activity in a dose-dependent manner. (n = 4; *P < 0.05; **P < 0.01; ***P < 0.001. PC: positive control, elastase inhibitor I).

Figure 3

Cell viability (%) of Ixora parviflora extract on human keratinocytes (HaCaT), mouse melanoma (B16) and human fibroblasts (Hs68). (n = 4).

Figure 4

Effect of Ixora parviflora extract on the UV-induced type I procollagen expression in human fibroblasts (a) and total collagen synthesis (b). IPE will upregulate type I procollagen expression and synthesis in a dose-dependent manner. (n = 4; significant difference versus control (non-UV-exposed): ***P < 0.001. Significant inhibition versus UV-exposed group: ^# P < 0.05; ^## P < 0.01; ^### P < 0.001. EGCG: (−)-epigallocatechin gallate.).

Figure 5

Effect of Ixora parviflora extract on the UV-induced Smad 3 and Smad 7 expression in human fibroblasts. (n = 4; significant difference versus control (non-UV-exposed): ***P < 0.001. Significant inhibition versus UV-exposed group: ^### P < 0.001. EGCG: (−)-epigallocatechin gallate.).

Figure 6

Effect of Ixora parviflora extract on the UV-induced MMP-1 (a), MMP-3 (b), MMP-9 (c), and TIMP-1 (d) expression in human fibroblasts. (n = 4; significant difference versus control (non-UV-exposed): ***P < 0.001. Significant inhibition versus UV-exposed group: ^# P < 0.05; ^### P < 0.001. EGCG: (−)-epigallocatechin gallate.).

Figure 7

Effect of Ixora parviflora extract on MMP-9 by gelatin zymography in the culture medium of human fibroblasts. (n = 3; significant difference versus control (non-UV-exposed): **P < 0.01. Significant inhibition versus UV-exposed group: ^# P < 0.05.).

Figure 8

Effect of Ixora parviflora extract on the UV-induced phosphorylation of MAP kinase in human fibroblasts. (n = 4; Significant difference versus control (non-UV-exposed): ***P < 0.001. significant inhibition versus UV-exposed group: ^# P < 0.05; ^## P < 0.01; ^### P < 0.001. EGCG: (−)-epigallocatechin gallate.).

Figure 9

Effect of Ixora parviflora extract on NO production in human fibroblasts (a) and the UV-induced expression of COX-2 (b). Human fibroblasts (Hs68) were treated with/without UV 40 mJ/cm² and Ixora parviflora extract (IPE) of 1, 5, 10, and 50 μg/mL. (n = 3; Significant difference versus control (non-UV-exposed): ***P < 0.001. significant inhibition versus UV-exposed group: ^# P < 0.05; ^## P < 0.01; ^### P < 0.001; EGCG: (−)-epigallocatechin gallate.).