Metabolism and Mass Balance of the Novel Nonsteroidal Androgen Receptor Inhibitor Darolutamide in Humans.

The biotransformation and excretion of darolutamide were investigated in a phase I study. Six healthy male volunteers received a single dose of 300 mg 14C-darolutamide as an oral solution in the fasted state. Plasma, urine, and feces samples were analyzed for mass balance evaluation by liquid scintillation counting (LSC). Metabolite profiling and identification were determined using liquid chromatography mass-spectrometry with off-line radioactivity detection using LSC. Complete mass balance was achieved, with mean radioactivity recovery of 95.9% within 168 hours (63.4% in urine, 32.4% in feces). The administered 1:1 ratio of (S,R)- and (S,S)-darolutamide changed to approximately 1:5, respectively, in plasma. Darolutamide and the oxidation product, keto-darolutamide, were the only components quantifiable by LSC in plasma, accounting for 87.4% of total radioactivity, with a 2.1-fold higher plasma exposure for keto-darolutamide. Aside from darolutamide, the most prominent metabolites in urine were O-glucoronide (M-7a/b) and N-glucuronide (M-15a/b), as well as pyrazole sulfates (M-29, M-24) and glucuronides (M-21, M-22) resulting from oxidative cleavage of the parent. The darolutamide diastereomers were mainly detected in feces. In vitro assays showed that darolutamide metabolism involves a complex interplay between oxidation and reduction, as well as glucuronidation. Interconversion of the diastereomers involves oxidation to keto-darolutamide, primarily mediated by CYP3A4, followed by reduction predominantly catalyzed by cytosolic reductase(s), with aldo-keto reductase 1C3 playing the major role. The latter reaction showed stereoselectivity with preferential formation of (S,S)-darolutamide. SIGNIFICANCE STATEMENT: The metabolism and excretion of darolutamide in humans revealed that oxidation (CYP3A4) and glucuronidation (UGT1A9, UGT1A1) were the main metabolic routes of elimination. Direct excretion also contributed to overall clearance. The two pharmacologically equipotent diastereomers of darolutamide interconvert primarily via oxidation to the active metabolite keto-darolutamide, followed by reduction predominantly by cytosolic reductase(s). The latter reaction showed stereoselectivity with preferential formation of (S,S)-darolutamide. Data indicate a low drug-drug interaction potential of darolutamide with inducers or inhibitors of metabolizing enzymes.

Absorption, distribution, metabolism and excretion of darolutamide (a novel non-steroidal androgen receptor antagonist) in rats.

1. Darolutamide is a novel selective androgen receptor antagonist consisting of two pharmacologically equipotent diastereoisomers. The absorption, distribution, metabolism and excretion properties of darolutamide in rats are reported.2. Non- or [14C]-labelled darolutamide, its diastereoisomers and major metabolite were studied in intact and bile duct-cannulated rats (oral and intravenous administration), and rat hepatocytes.3. Darolutamide was quickly (1 h to reach maximum plasma concentration) and completely absorbed after oral administration. Absolute bioavailability was high. Keto-darolutamide was the most abundant metabolite in rat hepatocytes and the only major one in plasma. Interconversion between diastereoisomers was observed.4. After oral administration, radioactivity distributed widely and homogeneously. Penetration into brain was low (brain/blood ratio = 0.079). Elimination was rapid from most tissues. Excretion occurred rapidly, and routes were similar irrespective of administration routes. Complete mass balance was reached by 168 h post-dose. Most radioactivity (61-64%) was excreted in faeces, while relevant amounts (30-33%) were also excreted into urine. The main clearance routes were metabolism via oxidative reactions and glucuronidation. After intravenous administration, a relevant extent of the dose (20%) underwent extrabiliary excretion as darolutamide.

Antioxidant activity of isolated ellagitannins from red raspberries and cloudberries.

Ellagitannins from red raspberries (Rubus idaeus) and cloudberries (Rubus chamaemorus) were isolated by using column chromatography and preparative HPLC. The berry phenolic isolates consisted of 80% (cloudberry) and of 60% (raspberry) of ellagitannins, with raspberries also containing anthocyanins. The main ellagitannins of both raspberries and cloudberries were identified by ESI-MS to consist of the dimeric sanguiin H-6 and the trimeric lambertianin C. Monomeric ellagitannins such as casuarictin in raspberries and pedunculagin in cloudberries were also found. The antioxidant activity of the berry phenolic isolate, ellagitannin isolate (mixture), ellagitannin main fraction (dimer and trimer), and ellagic acid was studied in bulk and emulsified methyl linoleate, in human low-density lipoprotein in vitro, and the radical scavenging activity was studied in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test. Cloudberry and red raspberry ellagitannins were highly effective as radical scavengers. Berry ellagitannins also showed significant antioxidant activity toward oxidation of both human LDL and methyl linoleate emulsions. However, only weak or moderate antioxidant activity was exhibited by ellagitannins toward oxidation of bulk oil. Thus, ellagitannins contribute significantly to the antioxidant capacity of cloudberries and red raspberries in lipoprotein and lipid emulsion environments, the latter being more relevant for food applications.

Berry phenolics: antimicrobial properties and mechanisms of action against severe human pathogens.

Antimicrobial activity and mechanisms of phenolic extracts of 12 Nordic berries were studied against selected human pathogenic microbes. The most sensitive bacteria on berry phenolics were Helicobacter pylori and Bacillus cereus. Campylobacter jejuni and Candida albicans were inhibited only with phenolic extracts of cloudberry, raspberry, and strawberry, which all were rich in ellagitannins. Cloudberry extract gave strong microbicidic effects on the basis of plate count with all studied strains. However, fluorescence staining of liquid cultures of virulent Salmonella showed viable cells not detectable by plate count adhering to cloudberry extract, whereas Staphylococcus aureus cells adhered to berry extracts were dead on the basis of their fluorescence and plate count. Phenolic extracts of cloudberry and raspberry disintegrated the outer membrane of examined Salmonella strains as indicated by 1-N-phenylnaphthylamine (NPN) uptake increase and analysis of liberation of [14C]galactose- lipopolysaccharide. Gallic acid effectively permeabilized the tested Salmonella strains, and significant increase in the NPN uptake was recorded. The stability of berry phenolics and their antimicrobial activity in berries stored frozen for a year were examined using Escherichia coli and nonvirulent Salmonella enterica sv. Typhimurium. The amount of phenolic compounds decreased in all berries, but their antimicrobial activity was not influenced accordingly. Cloudberry, in particular, showed constantly strong antimicrobial activity during the storage.

Catechins and procyanidins in berries of vaccinium species and their antioxidant activity.

The fractions of monomeric catechins and the fractions of dimeric and trimeric procyanidins were extracted and concentrated from wild berries of Vaccinium species to study their antioxidant activities. The compositions of the fractions were analyzed using high-performance liquid chromatography combined with diode-array and electrospray ionization mass spectrometric detection. Rare A-type dimers and trimers were identified as the predominant procyanidins in wild lingonberry, cranberry, bilberry, and bog whortleberry. Lingonberry and cranberry catechin and procyanidin fractions as well as bog whortleberry catechin fraction were good scavengers of radicals in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and more efficient than the respective bilberry fractions. Bog whortleberry procyanidin fraction was less active, this being mainly due to the lower content of these compounds. Fractions from lingonberry, cranberry, and bilberry were equally efficient in inhibiting the oxidation of methyl linoleate emulsion, but differences among the berries were found in their abilities to inhibit low-density lipoprotein (LDL) oxidation. Catechins, the monomers, exhibited comparable activity to the fractions containing dimers and trimers in inhibiting the oxidation of methyl linoleate emulsion and human LDL. Bog whortleberry catechins were excellent antioxidants toward the oxidation of human LDL. Radical scavenging and antioxidant activities of Vaccinium berry fractions were attributable to the their composition of catechins and procyanidins. In conclusion, Vaccinium catechins as well as dimeric and trimeric procyanidins provide substantial antioxidant protection.

Antioxidant activity of anthocyanins and their aglycons.

The antioxidant activity of the six common anthocyanidins, pelargonidin, cyanidin, delphinidin, peonidin, petunidin, and malvidin, and their glycosidic forms was evaluated in three lipid-containing models [human low-density lipoprotein (LDL) and bulk and emulsified methyl linoleate]. In addition, the radical scavenging activity of the compounds against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was studied. Most anthocyanins and their aglycons acted as strong antioxidants in emulsion and LDL. Many compounds showed an activity comparable to the well-known antioxidants alpha-tocopherol, Trolox, catechin, and quercetin. In bulk methyl linoleate, anthocyanins and anthocyanidins possessed only a weak antioxidant activity or even oxidation-promoting activity. Depending on the anthocyanidin, different glycosylation patterns either enhanced or diminished the antioxidant power. For the most part, the activities of the glycosides and the aglycons did not differ remarkably in emulsion. In LDL the aglycons showed in general higher activities than the glycosides. In bulk oil, to the contrary, the glycosides were more effective than the aglycons.