Exposure to UV radiation up-regulates the synthesis of matrix metalloproteinases (MMPs), a group of matrix-degrading enzymes. MMPs are regarded as promising therapeutic targets and the development of effective inhibitors is an important research focus. The plant Pothomorphe umbellata has been shown to exert a potent antioxidant activity on the skin and to delay the onset and reduce the incidence of UVB-induced chronic skin damage. The aim of the present study was to determine the effect of P. umbellata ethanolic root extract on MMP-2 and MMP-9. The in vitro inhibition of MMP-2 and MMP-9 was measured by gelatin zymography in the presence of different concentrations of P. umbellata extract, as well as in the presence of its isolated active principle 4-nerolidylcatechol (4-NC). The inhibitory effect of the P. umbellata extract was stronger than that of 4-NC. Gelatin zymography and histological analysis revealed that P. umbellata was able to inhibit constitutive MMP-9 activity in vivo in mice sacrificed 2 h after UVB irradiation. The intensity of the MMP-2 band was unchanged. Our data contribute to the elucidation of the mechanism of prevention of photoaging by P. umbellata and may provide a rational basis for the use of this plant in prophylaxis against and treatment of skin cancer.
Background: We aimed to evaluate the ascorbic acid concentration in secondary aqueous humour (AH) from glaucomatous patients and to compare it with primary AH from primary open‐angle glaucoma patients and non‐glaucomatous patients.
Methods: Primary AH samples were prospectively obtained from clinically uncontrolled primary open‐angle glaucoma patients and senile cataract patients (controls) prior to trabeculectomy and cataract surgery. Secondary AH samples were obtained from eyes with previous intraocular surgery, prior to trabeculectomy or cataract surgery. AH (0.1 mL) was aspirated by inserting a 26‐gauge needle into the anterior chamber just before surgery and then immediately stored at −80°C. The ascorbic acid concentration was determined in a masked fashion by high‐pressure liquid chromatography.
Results: A total of 18 patients with senile cataract, 16 glaucomatous patients with primary AH (no previous intraocular surgery) and 11 glaucomatous patients with secondary AH (previous intraocular surgery) were included. There was no difference in mean age between groups (P = 0.15). The mean ± standard deviation concentration of ascorbic acid in the secondary AH from glaucomatous patients (504 ± 213 µmol/L [95% confidence interval {CI}, 383–624]) was significantly lower than the concentration of ascorbic acid found in the primary aqueous of primary open‐angle glaucoma (919 ± 427 µmol/L [95% CI, 709–1128]) and control patients (1049 ± 433 µmol/L [95% CI, 848–1249]; P < 0.01, Kruskal‐Wallis test).
Conclusions: The ascorbic acid concentration in secondary AH of glaucomatous patients was approximately twofold lower in comparison with primary AH of glaucomatous and cataract patients. The implications of a reduced concentration of ascorbic acid in the secondary AH deserve further investigation.
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