Photobiological properties of a new tetramethylfuroquinolinone

Can a mixed damage interfere with DNA‐prottein cross‐links repair?

“…marins, it is incapable of inducing ISC [1]. Therefore, using FQ and the double irradiation, we can selectively induce DPC and analyze their biological consequences.…”

“…Now we report some preliminary data obtained comparing FQ to a well-known and very active linear furocoumarin, 4,5',8-trimethylpsoralen (TMP). Both TMP and FQ can photobind to DNA by UVA irradiation to a high and very similar extent; on the other hand, only TMP shows a strong capacity of inducing ISC [1,5]. As a reference compound we chose 8-methoxypsoralen (8-MOP).…”

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Studying the damage induced into DNA by furocoumarin sensitization, particularly covalent DNA-protein cross-links (DPC), we have observed that an angelicin isoster, namely 1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one (FQ), can selectively induce DPC [1,2] when used by means of the wellknown method called double irradiation. This method was introduced studying furocoumarin interstrands cross-links (ISC), which are formed by a biphotonic reaction [3].

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Photochemical and photobiological properties of furocoumarins and homologues drugs

“…A monofunctional furocoumarin can be obtained by several ways: blocking one of its two photoreactive sites by insertion of a suitable group, as for 3-carbethoxypsoralen [15], or by cumulating a fourth nucleus, e.g., the pyridopsoralens having a pyridine condensed at 3,4 positions [16] and benzopsoralens in which the fourth nucleus is a benzenic one at 4 , 5 position [17]. We also studied several new angelicin derivatives, which, for the geometric parameters of their angular molecular structure, can hardly induce ISC [18]. Thus, we obtained various active and interesting angelicins; the best one is certainly 4, 6, 4 -trimethylangelicin [18].…”

“…We also studied several new angelicin derivatives, which, for the geometric parameters of their angular molecular structure, can hardly induce ISC [18]. Thus, we obtained various active and interesting angelicins; the best one is certainly 4, 6, 4 -trimethylangelicin [18]. Recently we also studied some homologues drugs which can be considered angelicin isosters; the most interesting compounds are two angular furoquinolinones, FQ (1,4,6,8-tetramethyl-2H-furo[2,3-h]quinolin-2-one, according to JUPAC) [19] and HFQ (4,6,8,9-tetramethyl-2H-furo[2,3-h]-quinolin-2-one) having a nitrogen atom replacing the oxygen at 1 position; the main difference between these two derivatives is the presence or the absence of a methyl group at the nitrogen atom.…”