ABSTRACT
Tyrosinase is a metalloenzyme involved in o-hydroxylation of monophenols and oxidation of o-diphenols to o-quinones, with formation of brown or black pigments (melanines). Tyrosinase inhibitors are of great interest in medicine and cosmetics (skin whitening compounds), but also in food and beverage industry (antibrowning agents). Here we report on the activity as mushroom tyrosinase inhibitors of a series of hydroxyphenyl thiosemicarbazones (1-5): one of them revealed an inhibitory activity stronger than kojic acid, used as reference. Enzymatic inhibition activity was confirmed by colorimetric measurements on small wheels of Fuji apples treated with the hydroxyphenyl thiosemicarbazones. The mechanism of action of compounds 1-5 was investigated by molecular modelling and by studying in solution their speciation with Cu(II) ions, the ions in the active site of the enzyme. Finally, compounds 1-5 were tested on human fibroblasts: they are not cytotoxic and they do not activate cells in a pro-inflammatory way.
Subject(s)
Agaricales/enzymology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Maillard Reaction/drug effects , Monophenol Monooxygenase/antagonists & inhibitors , Thiosemicarbazones/chemistry , Thiosemicarbazones/pharmacology , Catalytic Domain , Humans , Kinetics , Monophenol Monooxygenase/chemistry , Monophenol Monooxygenase/metabolism , Oxidation-Reduction/drug effectsABSTRACT
Although internal mammary artery pseudoaneurysms are a rare vascular abnormality, they are sometimes seen after sternotomy, diagnostic and therapeutic vascular access or penetrating chest trauma. To our knowledge, internal mammary artery pseudoaneurysm caused by pulmonary actinomycosis has not been reported previously. We report a case of pseudoaneurysm of the left internal mammary artery caused by pulmonary actinomycosis. A 50-year-old woman initially presented with clinical and radiological features of pneumonia, for which she was treated empirically with antibiotics. Later, she developed haemoptysis along with pain and swelling in the left upper chest wall. Multidetector CT (MDCT) with CT angiography showed a cavitating mass in the left upper lobe of the lung that infiltrated into the chest wall and a pseudoaneurysm of the left internal mammary artery. Imaging suggested that the lung mass resulted from pulmonary actinomycosis, which was confirmed by the histopathology of a fine-needle aspiration specimen.
