1.4-Naphthoquinone. physical properties

Physical Properties. - Naphtho[2,3-c][1,2,5]thiadiazol-4,9-dione and its selenium analogue have been studied by X-ray crystallography. Both show significant ir interaction of the chalcogen diimide with the it system of the naphthoquinone. ... 

Prokopenko et al described that some naphthoquinones normalized or increased the immune response in rats after intensive physical load. The naphthoquinones induced the development of immunostimulating properties in heavy red blood cells by direct action on cell membranes or indirectly through proteolytic enzymes secreted by hepatocytes [212]. Other activities described for several naphthoquinones related to lapachol are antipsoriatic [213], larvicidal and insecticidal, [214-215] molluscicidal [216], and mutagenicity in salmonella [217]. The potential use of lapachol in cosmetics has been published too [218]. 

Menaquinone-n (MK ), or vitamin K2( ), stands for 2-methyl-3-multiprenyl-1,4-naphthoquinone, where n indicates the amount of isoprene units in the side chain, a number naturally between 4 and 13. Sometimes one (or more) of the double bonds in the side chain is saturated. Physical and chemical properties of menaquinones are similar to those of VKl, with the exception of the lipohilic character, due to different design of the side chain. MK s are formed by bacteria (e.g., Escherichia coli. Staphylococcus aureus, Eubacterium lentum etc.) of the intestine, the most common configuration is -trans. Other stores of MK s were found to be animal liver (mainly MK7-13) and bone (5). 

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