Browsing by Author "Collins, Margaret S."
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- Anti-Pneumocystis carinii and antiplasmodial activities of primaquine-derived imidazolidin-4-onesPublication . Vale, Nuno; Collins, Margaret S.; Gut, Jiri; Ferraz, Ricardo; Rosenthal, Philip J.; Cushion, Melanie T.; Moreira, Rui; Gomes, PaulaA series of primaquine-derived imidazolidin-4-ones were screened for their in vitro activity against Pneumocystis carinii and Plasmodium falciparum W2 strain. Most compounds were active against P. carinii above 10 lg/mL and displayed slight to marked activity. The imidazolidin-4-ones most active against P. carinii were also those most active antiplasmodial agents, in the lM range. One of the tested imidazolidin-4-ones was slightly more active than the parent primaquine and may represent a lead com pound for the development of novel anti-P. carinii 8-aminoquinolines with increased stability and resistance to metabolic inactivation.
- Anti-pneumoscystis carinni activitiy of primaquine imidazolidin-4-onesPublication . Vale, Nuno; Ferraz, Ricardo; Azevedo, Joana; Araújo, Maria João; Moreira, Rui; Collins, Margaret S.; Cushion, Melanie T.; Gomes, PaulaPneumocystis pneumonia (PCP) is one of the most frequent causes of mortality among HIV-infected patients. Primaquine (PQ) is an antimalarial 8-aminoquinoline effective against PCP when given in combination with clindamycin. This has drawn the attention of Medicinal Chemists towards the anti-PCP activity of 8-aminoquinolines, not only confined to those exhibiting antimalarial activity [1]. It is thought that anti-PCP 8-aminoquinolines exert their anti-PCP activity by acting on the electronic transport and redox system of the P. carinii pathogen [1]. Recently, our research group has been developing imidazolidin-4-one derivatives of PQ (Scheme 1), targeting novel compounds with improved therapeutic action, namely, higher resistance to metabolic inactivation, lower toxicity and equal or higher antimalarial activity than that of the parent drug [2,3]. These imidazolidin-4-ones were seen to block the transmission of rodent malaria, caused by Plasmodium berghei on BalbC mice, to the mosquito vector Anopheles stephensi [3]. The anti-PCP activity of our PQ derivatives is now under study and preliminary in vitro assays [4] show that some of the compounds exhibit slight to moderate activity after a 72 h incubation period against P. carinii. In one case, the IC50 was comparable to that of parent PQ. Both these studies and forthcoming results from ongoing biological assays will be presented and discussed.
- Chloroquine Analogues as Leads against Pneumocystis Lung PathogensPublication . Gomes, Ana; Ferraz, Ricardo; Ficker, Lauren; Collins, Margaret S.; Prudêncio, Cristina; Cushion, Melanie T.; Teixeira, Cátia; Gomes, PaulaThe impact of Pneumocystis pneumonia (PcP) on morbidity and mortality remains substantial for immunocompromised individuals, including those afflicted by HIV infection, organ transplantation, cancer, autoimmune diseases, or subject to chemotherapy or corticosteroid-based therapies. Previous work from our group has shown that repurposing antimalarial compounds for PcP holds promise for treatment of this opportunistic infection. Following our previous discovery of chloroquine analogues with dual-stage antimalarial action both in vitro and in vivo, we now report the potent action of these compounds on Pneumocystis carinii in vitro Identification of chloroquine analogues as anti-PcP leads is an unprecedented finding.