Investigating the Activity Spectrum for Ring-Substituted 8-Hydroxyquinolines

Abstract

In this study, a series of fourteen ring-substituted 8-hydroxyquinoline derivatives were prepared. The synthesis procedures are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than the standards isoniazid or fluconazole. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed.

Photosynthetic Inhibitors

“…Details about the preparation of the mentioned compounds can be found in the cited references and will not be covered herein since this is not the focus of this book chapter. Several papers has been published in the last few years dealing with the synthesis of various aromatic nitrogenated compounds and their biological evaluation as photosynthetic inhibitors (Jampilek et al, 2009a,b;Musiol et al, 2007;Musiol et al, 2008;Musiol et al, 2010;Otevrel et al, 2010). The general structures and their associated most active compounds are presented in Figure 7 along with the IC 50 data.…”

“…In another series of hydroxilated derivatives, among the fourteen ring-substituted 8-hydroxyquinoline derivatives (33), two compounds (33a, 33b) showed moderate inhibitory activity (Musiol et al, 2010). The investigation of the influence of twelve ring substituted salicylanilides and carbamoylpehnylcarbamates, represented by the general structure (34), on photosynthetic apparatus afforded compounds (34a-34d) (Figure 7) with biological activities compared do diuron.…”

Preparation and Herbicidal Activity of Halogenated 8-Hydroxyquinoline-2-carboxanilides

“…In addition, according to the results reported recently, some quinoline derivatives and their analogues/isosteres also showed noteworthy herbicidal activities [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Although at present approximately 20 mechanisms of action of herbicides are known [21], over 50% of commercially available herbicides act by reversible binding to photosystem II (PS II), a membrane-protein complex in the thylakoid membranes, which catalyses the oxidation of water and the reduction of plastoquinone [22], and thereby inhibit photosynthesis [23][24][25].…”

“…Due to this interaction, interruption of the photosynthetic electron transport occurs. In the context of the previously-described azanaphtalenes and their isosteres [7][8][9][10][11][12][13][14][15][16][17][18][19][20], new simple modifications of quinoline that can possess interesting biological activity were investigated. The compounds were tested for their photosynthesis-inhibiting activity -the inhibition of photosynthetic electron transport in spinach chloroplasts (Spinacia oleracea L.).…”

“…Although at present approximately 20 mechanisms of action of herbicides are known [21], over 50% of commercially available herbicides act by reversible binding to photosystem II (PS II), a membrane-protein complex in the thylakoid membranes, which catalyses the oxidation of water and the reduction of plastoquinone [22], and thereby inhibit photosynthesis [23][24][25]. Some organic compounds, possessing an amide (-NHCO-) group, e.g., substituted anilides [11,[15][16][17][18]20], or a wide variety of compounds containing the quinoline system [9,10,[12][13][14]19] were found to interact with tyrosine radicals Tyr Z and Tyr D (or their surroundings) which are situated in D 1 and D 2 proteins on the donor side of PS II. Due to this interaction, interruption of the photosynthetic electron transport occurs.…”