MMP-Inhibitory Effects of Flavonoid Glycosides from Edible Medicinal Halophyte Limonium tetragonum

Abstract

Limonium tetragonum has been well-known for its antioxidative properties as a halophyte. This study investigated the antimetastasis effect of solvent-partitioned L. tetragonum extracts (LTEs) and isolated compounds on HT1080 mouse melanoma cell model with a focus on matrix metalloproteinase (MMP) activity and TIMP and MAPK pathways. Upregulation and stimulation of MMPs result in elevated degradation of extracellular matrix which is part of several complications such as metastasis, cirrhosis, and arthritis. The anti-MMP capacity of LTEs was confirmed by their MMP-inhibitory effects, regulation of MMP and TIMP expression, and suppression of MAPK pathway. Among all tested LTEs, 85% aq. MeOH and n-BuOH were found to be most active fractions which later yielded two known flavonoid glycosides, myricetin 3-galactoside and quercetin 3-o-beta-galactopyranoside. Anti-MMP potential of the compounds was confirmed by their ability to regulate MMP expression through inhibited MAPK pathway activation. These results suggested that L. tetragonum might serve as a potential source of bioactive substances with effective anti-MMP properties.

Figure 1

(a) Effect of solvent-partitioned L. tetragonum extracts (LTEs) on cell viability of HT1080 human fibrosarcoma cells. (b) Effect of LTEs on enzymatic activity of MMP-2 and MMP-9 tested by gelatin zymography. Values are mean ± SD (n = 3).

Figure 2

Effect of solvent-partitioned L. tetragonum extracts (LTEs) on protein levels of MMP-2 and MMP-9, TIMP-1 and TIMP-2, p38, JNK, and ERK observed by immunoblotting. β-Actin was used as an internal standard.

Figure 3

Basic isolation scheme and structural elucidation of two isolated flavonoid glycosides. A: myricetin 3-galactoside; B: quercetin 3-o-beta-galactopyranoside.

Figure 4

Effects of compounds A and B on enzymatic activity of MMP-2 and MMP-9 tested by gelatin zymography with cell lysates of treated HT1080 fibrosarcoma cells. A: myricetin 3-galactoside; B: quercetin 3-o-beta-galactopyranoside.

Figure 5

Effects of compounds A and B on mRNA (a) and protein (b) levels of MMP-2 and MMP-9 and TIMP-1 and TIMP-2 observed by RT-PCR and immunoblotting, respectively, in HT1080 human fibrosarcoma cells. β-Actin was used as an internal standard. A: myricetin 3-galactoside; B: quercetin 3-o-beta-galactopyranoside.

Figure 6

Effect of compounds A and B on phosphorylated (P-) and native protein levels of p38, JNK, and ERK in HT1080 human fibrosarcoma cells. β-Actin was used as an internal standard.