CP-arene oxides: the ultimate, active mutagenic forms of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs)

Abstract

The bacterial mutagenic response (Ames-assay, Salmonella typhimurium strain TA98 ± S9-mix) of a series of monocyclopentafused polycyclic aromatic hydrocarbons (CP-PAHs) identified in combustion exhausts, viz. cyclopenta[cd]pyrene (1), acephenanthrylene (2), aceanthrylene (3) and cyclopenta[hi]chrysene (4), is re-evaluated. The mutagenic effects are compared with those exerted by the corresponding partially hydrogenated derivatives, 3,4-dihydrocyclopenta[cd]pyrene (5), 4,5-dihydroacephenanthrylene (6), 1,2-dihydroaceanthrylene (7) and 4,5-dihydrocyclopenta[hi]chrysene (8). It is shown that the olefinic bond of the externally fused five-membered ring of 1, 3 and 4 is of importance for a positive mutagenic response. In contrast, whilst CP-PAH 2 is found inactive, its dihydro analogue (6) shows a weak metabolism-dependent response. The importance of epoxide formation at the external olefinic bond in the five-membered ring is substantiated by the bacterial mutagenic response of independently synthesized cyclopenta[cd]pyrene-3,4-epoxide (9), acephenanthrylene-4,5-epoxide (10), aceanthrylene-1,2-epoxide (11) and cyclopenta[hi]chrysene-4,5-epoxide (12). Their role as ultimate, active mutagenic forms, when CP-PAHs 1, 3 and 4 exhibit a positive mutagenic response, is confirmed. Semi-empirical Austin Model 1 (AM1) calculations on the formation of the CP-arene oxides (9-12) and their conversion into the monohydroxy-carbocations (9a-12a and 9b-12b) via epoxide-ring opening support our results. For 2 and 4, which also possess a bay-region besides an annelated cyclopenta moiety, the calculations rationalize that epoxidation at the olefinic bond of the cyclopenta moiety is favoured.

Identification of acephenanthrylene and aceanthrylene in aerosol and its environmental implication

“…Hence, it is likely that acephenanthrylene and aceanthrylene in aerosol undergo chemical changes during the sediment process, and transform to other compounds. As well, since the decay life of acephenanthrylene and aceanthrylene is relatively short, its double bonds can be easily oxidized to cycleoxygen products [11] . There are no acephenanthrylene and aceanthrylene detected in aerosol from desert areas, indicating that chemical changes took place during the long distant immigration of acephenanthrylene and aceanthrylene.…”

“…Cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) are generally considered with enhanced bioactivity (mutagenic and carcinogenic effects) compared to PAHs without the cyclopenta moiety [9] . Aceanthrylene was more mutagenic than its isomer, acephenanthrylene [10] , but the epoxide of the latter exhibits direct-acting mutagenic response [11] . Acephenanthrylene can isomerize to more mutagenic fluoranthene [12] .…”

Gas phase adiabatic electron affinities of cyclopenta-fused polycyclic aromatic hydrocarbons

“…strong oxidants. In addition, the AEAs of CP-PAHs warrant further investigations of the properties of their radical anions in connection with their possible occurrence in the interstellar medium [6] and as an aid for the identification of bio-active representatives [7,11,12]. …”

“…facile (consecutive) one-electron reduction processes [3], anomalous fluorescence [4] and deviant aromatic character [5], and, their alleged presence (in charged form) in the interstellar medium [6]. In addition, CP-PAHs were found to possess bio-activity [7]. This is of interest since CP-PAHs have been identified as prevalent environmental pollutants that are invariably generated during incomplete combustion processes [8].…”

Determination of polycyclic aromatic hydrocarbons in water by a novel mesoporous‐coated stainless steel wire microextraction combined with HPLC

“…The analysis of polycyclic aromatic hydrocarbons (PAHs) in environmental samples has become an increasingly important topic in analytical chemistry because of the carcinogenic and mutagenic properties of these compounds [1,2]. Of the 21 most often found PAHs, the US Environmental Protection Agency has promulgated 16 PAHs in its list of 129 priority pollutants.…”