Inhibition of tumour promoter-induced Epstein- Barr virus activation by diospyrin, a plant-derived antitumour compound, and its synthetic derivatives

Abstract

Inhibition of tumour promotion by diospyrin, a plant‐derived bioactive bisnaphthoquinonoid compound, and its two derivatives was examined by an in vitro assay utilizing the activation of Epstein–Barr virus (EBV) early antigen (EA) expression in EBV‐ genome‐ carrying human lymphoblastoid cells. Synthetic modifications of diospyrin resulted in positive improvement of its activity against tumour promotion by inhibiting EBV EA expression in Raji cells induced by 12‐o‐tetradecanoylphorbol‐13‐acetate (TPA). © 1997 John Wiley & Sons, Ltd.

Anti-cancer activities of diospyrin, its derivatives and analogues

“…The bioactivity of derivative 4 of diospyrin [32] was proposed to act via a one-electron reduction mechanism. Similar results regarding the anti-cancer activity of diospyrin have also been reported [37]. Enzymatic two-electron reduction is catalyzed mainly by DT-diaphorase (NADPH quinone oxidoreductase) resulting in the formation of hydroquinone which undergoes auto-oxidation in aerobic conditions to give H 2 O 2 , which in turn further reacts with Fe (II) to generate reactive oxygen species (OH À ) via the Fenton reaction (Fig.…”

“…Certain serum enzymes (lactate dehydrogenase, alkaline phosphatase and glutamate oxaloacetate transaminase) were also reported to recover to close to normal levels. In 1997, the activity of diospyrin and synthetic derivatives 2 and 3 were tested on the Raji cell line, an EpsteineBarr virus (EBV)-genome-carrying human lymphoblastoid cell line [37]. Total inhibition of expression of EBV was noted with 3 (concentration 10 mg/ml), whereas compound 2 was less active at a concentration of 40 mg/ml.…”

Reviews on 1,4-naphthoquinones fromDiospyrosL.

“…The bioactivity of diospyrin is supposed to act via an one-electron reduction mechanism [97]. Isodiospyrin showed cytotoxic activity in tumor cell lines.…”

Separation methods of quinonoid constituents of plants used in Oriental traditional medicines

“…The leaves of D. melanoxylon have great commercial value for wrapping country cigarettes (bidi) in India. The pharmacological and biocidal studies on crude extracts and quinonoids from this genus are: piscicidal and molluscicidal [118][119][120], anti-inflammatory [121][122][123][124], antibacterial [125,126], anti-cancer [127][128][129], anti-tumour promoter [130] and anti-tubercular activities [131].…”