Antiprotozoal activity

Metronidazole — see also Imidazole, 1-(2-hydroxy-ethyl)-2-methyl-5-nitro-antiprotozoal activity, 1, 180 veterinary use, 1, 208 mode of action, 1, 208 Metyrapol metabolism, 1, 234 Metyrapone... 

Many nitroimidazoles possess antiprotozoal activity. One of these is bamnidazole (29). Synthesis involves reaction of imidazole carbonate 28 with ammonia. 

Keywords Antibacterial activity Antimycotic activity Antiprotozoal activity Antiviral activity Cathechins Proanthocyanidins... 

In a similar way, several studies have been devoted to the study of antiprotozoal activity of catechins occurring in green tea extracts. The trypanocidal... 

Only a few studies have reported the antiprotozoal activity of proantho-cyanidins. Bioassay-guided fractioning of the extract of Geranium niveum led to the isolation of two new A-type proanthocyanidins epf-afzelechin-(4j6 8,2j6 0 7)-afzelechin and EC-(4/l 8,2/1 0 7)-afzelechin... 

Imidazoles devoid of the nitro group no longer show useful antiprotozoal activity, however, several... 

Singh SB, Zink DL, Liesch JM, Mosley RT, Dombrowski AW, Bills GF, Darkin-Rattray SJ, Schmatz DM, Goetz MA. (2002) Structure and chemistry of apicidins, a class of novel cychc tetrapeptides without a terminal a-keto epoxide as inhibitors of histone deacetylase with potent antiprotozoal activities. J Org Chem 67 815-825. 

Galal AM, Gul W, Slade D, Ross SA, Feng S, Hollingshead MG Alley MC, Kaur G ElSohly MA. (2009) Synthesis and evaluation of dihydroartemisinin and dihydroartemisitene acetal dimers showing anticancer and antiprotozoal activity. Bioorg Med Chem 17 741-751. 

Replacing the electrophilic epoxy ketone moiety in TPX by a reversible zinc chelator such as a hydroxamic acid was carried out by Yoshida et al. (Fig. 6) [51]. This modification led to a low nanomolar reversible inhibitor of the HDACl enzyme. Several other cyclic tetrapeptides containing the epoxyketone feature, such as chlamydocin, were converted into their hydroxamic acid coimterparts as well [52]. Additionally, the introduction of reversed hydroxamic acids (-N(OH)COR, with R = H or Me) onto the structure of Cyl-1 was reported to give potent HDAC inhibitors as illustrated in Fig. 6 [53]. Generally, the most potent inhibitors were the examples with R = H and m = 2. Apicidin, a cychc peptide more remotely related to TPX, exhibits potent antiprotozoal activity via HDAC inhibition in parasites [54]. 

Mechanism of Action An ant iparasiticthat interferes with the body s reaction to pyruvate ferredoxin oxidoreductase, an enzyme essential for anaerobic energy metabolism. Therapeutic Effect Produces antiprotozoal activity, reducing or terminating diarrheal episodes. 

Cultures of Streptomyces rimosus var paromomycinus characteristically develop UV absorption at 240 and 278 nm due to formation of malonomicin (22), a compound that shows antiprotozoal activity towards Trypanosoma congolense, the causative agent of sleping sickness in cattle [42]. Malonomicin contains an unique aminomalonic acid unit that, on brief heating in water, undergoes decarboxylation and results in a compound devoid of biological activity [43]. Hydrolysis of the compound yielded L-serine and racemic aspartic acid. The structure was elucidated by chemical and spectroscopic methods [43,44] and was confirmed by total synthesis [45]. 

Many patents describe the preparation of 1,3-oxazine derivatives as antibacterials and antifungals.21-22-27-69-81-87-89-90-129-300,301 Strong antiprotozoal activity of 5-bromo-5-nitrotetrahydro-l,3-oxazines, e.g., 126, was also registered.302-303 N-Nitroso derivatives were found to be... 

Encamacion DR, Franzblau SG, Tapia CA, Cedillo-Rivera R (2000) Screening of Marine Organisms for Antimicrobial and Antiprotozoal Activity. Pharm Biol 38 379... 

Of interest is a recently described yeast-based, nutrient-dependent viability screen for inhibitors of protozoal dihydrofolate reductase (DHFR) [43,44], Antiprotozoal activity of DHFR inhibitors is well known, and DHFR- yeast complemented with the DHFR gene derived from the malaria parasite P. falciparum have been used to characterize the molecular pharmacology of resistance to the antimalarial DHFR inhibitors pyrimethamine and cycloguanil [45,46], The subsequent development of a screen was based on the demonstration that the protozoal... 

Because of such extensive application in folk medicine, it is easy to understand the interest that the lapachol, the related naphthoquinones a-lapachone, P-lapachone and other naphthoquinones derivatives, have aroused as potential drugs. In fact, a broad variety of biological activities have been described for this kind of compounds. Some examples are antitumor promoting activities [11-12], inactivators of human cytomegalovirus protease [13], antiprotozoal activity [14], trypanocidal activity [15], anticancer activity [16], and antibacterial and antifungal activities [17]. 

Pentavalent arsenic compounds such as tryparsamide appear to require reduction to the trivalent state for antiparasitic activity (Figure 10.9C). Various arsenicals containing pentavalent arsenic have only slight in vitro antiprotozoal activity, whereas compounds containing trivalent arsenic are highly active. 

A-(nitrobenzimidazol-2-yl)pyridinium derivatives have been synthesized in order to study their antiprotozoal activity [693-695], A H and 13C NMR study has been carried out for structural determination of these compounds (S13C in Table 3.25). Quantitative structure-activity relationships (QSAR) between the in vitro antileish-manial activity of /V- ben zazolylpyridinium salts and their 13C NMR chemical shifts have been studied in order to determine the influence of benzimidazole substituents upon antileishmanial activity [695],... 

Antibiotics with antiprotozoal activity are not included in this chapter. These include clindamycin, co-trimoxazole-trimethoprim, dapsone, doxycycline and... 

This section consists of antiprotozoal drugs. Note that antimalarials are also antiprotozoals but have been described in a separate section Antibiotics with antiprotozoal activity are not included in this chapter. These include clindamycin, co-trimoxazole/trimethoprim, dapsone, doxycydine and metronidazole ... 

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