Provectus' intellectual property (IP) includes a family of US and international patents that protect the process by which pharmaceutical grade RB and related xanthenes
are produced, reducing the formation of previously unknown transhalogenated impurities that exist in commercial grade RB in uncontrolled amounts.
Provectus is a clinical-stage biotechnology company developing a new class of drugs for oncology and dermatology based on a wholly-owned family of chemical small molecules called halogenated xanthenes
This plant also causes kidney damage due to elevated hepatic and renal Xanthenes
' Oxidase activities due to Lantadine, the phytotoxin present in this plant (Sharma et al., 1981).
Yoon, "Fluorescent chemosensors based on spiroring-opening of xanthenes
and related derivatives," Chemical Reviews, vol.
Table 1 shows the phototoxicity and dark toxicity of the xanthenes
in HEp-2 after 6 h incubation with the dye.
The high quantum yield of fluorescence was reported for laser organic dyes (xanthenes
, oxazines, 7-aminocoumarins) .
These compounds or phytochemical constituents incorporate terpenes, flavonoid, bioflavonoid, benzophenones, xanthenes
and also a few metabolites, for example, tannins, saponins, cyanates, oxalate and anthrax-quinones .
The activity of hepatoprotective plants has been related to certain secondary metabolites, such as alkaloids, coumarins, carotenoids, flavonoids, glycosides, lignans, xanthenes
, lipids, monoterpenes, and organic acids (Oh et al., 2004; Yan et al., 2009).
Oncology company Provectus Biopharmaceuticals (NYSE MKT:PVCT) disclosed on Tuesday the receipt of the US patent covering additional aspects of its process for synthesizing halogenated xanthenes
, which is part of the family of compound of rose bengal.
Compound 1 displayed profound inhibition of xanthenes
oxidase with IC50 values of 11.920.01 u M, followed by compounds 2 and 3 with IC50 values of 73.74 u M and 97.120.01 u M respectively.
Patent 8,530,675, Process for the Synthesis of 4,5,6,7-tetrachloro-3',6'- dihydroxy-2',4',5',7'-tetraiodo-3H-spiro[isobenzofuran-1,9- xanthen]-3-one (Rose Bengal) and Related Xanthenes
. The application details a new process for the manufacture of Rose Bengal and related iodinated xanthenes
in high purity.
Several methods have been reported for the synthesis of xanthenes
which includes by using poly(4-vinyl pyridinium) perchlorate , task specific acidic ionic liquid [NMP] [H.sub.2]S[O.sub.4] , nano silica phosphoric acid , HCl[O.sub.4]-Si[O.sub.2] , proline triflate in water , Iodine , In[Cl.sub.3] , Sr[(OTf).sub.2]  and p-TSA .