Naphthopyrones

Song YG, Li H, Ye YH, Shan GY, Yang YM, Tan RX, Endophytic naphthopyrone metabolites are co-inhibitors of xanthine oxidase, SW1116 cell and some microbial growths, FEMS Microhilogy Letters 241 67—72, 2004. 

Watanabe, A. Fujii, I. Sankawa, U. Mayaga, M.E. Timbalake, W.E. Ebizuka, Y. (1999) Re-idaitification of Aspergillus nidulans wA gene to code for a pofyketide synthase of naphthopyrone. Tetrahedron Lett., 40,91-4. 

Cassia nomame (Sieb.) Honda C. obtusifolia L. C. tora L. Jue Ming Zi (Sicklepod) (seed) Anthraquinones such as emodin, chrysophanol, physcion, rhein aurantio-obtusin, obtusifolin, chryso-obtusin, naphthopyrones, obtusin, aurantio-obtusin rubrofusarin, nor-rubrofusarin, toralacton.33 Purgative, treat ophthalmia, hypercholesterolemia, vaginitis. 

The naphthopyrone, comantherin sulfate (650) was isolated from the crinoid Comantheria perplexa [520] and three naphthopyrones (651-653) were isolated from Comanthus parcivirrus timorensis. Both species were collected off Australia [521]. 

WAS) in Aspergillus oryzae. Initially, the expression strain produced the isocoumarin 38, which indicated that WAS is a heptaketide synthase (Fig. 2b). It was then realized that the expression construct used in this experiment had a deletion that resulted in the expressed WAS missing the final 67 amino acids of the C-terminal TE domain. When the complete wA gene was expressed, however, the heptaketide naphthopyrone YWAl 39 was produced (10). A series of experiments that involve step-wise shortening of the C-terminus of WAS showed that deletion of as few as 32 amino acids resulted in production of the isocoumarin 38. Site-directed mutagenesis of a conserved... 

Isotopic feeding experiments using C-labeled acetate indicated the folding pattern shown in Fig. 2b for the naphthopyrone... 

Thus, both the isocoumarin 38 and the naphthopyrone 39 must result from the cyclization of the common intermediate... 

Figure 34 PksA deconstruction, (a) Enzymatic domain architecture of PksA. (b) PksA utilizes a starter hexanoyl-CoA and seven malonyl-CoAs to produce the covalently linked intermediate (brackets). The PT domain acts as an aromatase/cyclase facilitating the closure of the first two rings on the intermediate. In the absence of the TE/CLC domain the intermediate undergoes C-O cyclization to spontaneously form the naphthopyrone. In the presence of the TE/CLC domain, the intermediate undergoes C-C cyclization to from the norsolorinic acid anthrone, which autooxidizes to form norsolorinic acid, (c) Observed PPant ejection ions confirming the structures of the proposed intermediates bound to the active site of the PksA T domain. The first intermediate (left) was detected on the T domain active site after incubation of SAT-KS-MAT with T domain alone. Incubation of SAT-KS-MAT with PT-T results in the formation of the intermediates containing first a single-cyclization product (middle) followed by a double-cyclization product (right).

Flavoparmelia euplecta Euplectin Naphthopyrones APP Cytotoxic agent Emst-Russell et al. (2000)... 

Emst-Russell MA, Chai CLL, Wardlaw JH et al (2000) Euplectin and coneuplectin, new naphthopyrones from the lichen Flavoparmelia euplecta. J Nat Prod 63 129-131 Esimone CO, Adikwn MU (1999) Antiniicrobial activity of the cytotoxicity of Ramalina farinacea. Fitoterapia 7 428-431... 

Ogura M, Cordell GA, Farnsworth NR 1977 Quinquangulin, a new naphthopyrone from Cassia quinquangulata (Leguminosae). Lloydia 40 347-351... 

Some pigments with a naphthopyrone structure have also been discovered in crinoids. Work on the pigments of crinoids began in the early 1970s and many details are provided by Grosser (1972), Scheuer (1973), Francesconi (1980) and more recently by Folmer et al. (2008) and Bokesdi et al. (2010). 

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