Novel renin inhibitors containing a non-peptide aminoalkanoyl moiety at P1-P1' position.

Six novel potential renin inhibitors have been designed and synthesized. All these inhibitors contained an unnatural aminoalkanoyl moiety at the central position P1- P1' of the molecule, which is attacked by renin. The moiety consists of pseudodipeptidic units, transition state analogues of a natural dipeptide of the parent substance: 4-amino-3-hydroxybutanoic acid (AHBA), 4-amino-5-(4-ethoxyphenyl)-3-hydroxypentanoic acid (AEPHPA), 4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA) or 4-amino-3-hydroxynonanoic acid (AHNA). An unnatural moiety, 4-methoxyphenylalanylhistydyl (Phe(4-OMe)-His) has been introduced at the P3-P2 position of the obtained compounds. Five compounds contain isoamylamide of 6-aminohexanoic acid (epsilon-Ahx-laa) at the P2'-P3' position. One of designed inhibitors has been obtained in the form of an ethyl ester. The in vitro renin inhibitory activity of all synthesized compounds is contained within the range 10(-6) - 10(-8) M. The compound in the form of an ethyl ester has proven to be the most active (IC50 = 1.3 x 10(-8) M) but also susceptible to enzymatic degradation. The other five inhibitors were stable to chymotrypsin.

Early-effect of bariatric surgery (Scopinaro method) on intestinal hormones and adipokines in insulin resistant Wistar rat.

Bariatric surgery consists in duodenal exclusion from the food passage in obese patients with coexistent type 2 diabetes. Nowadays bariatric surgery is considered the most effective method of glycemic index normalization and insulin resistance reduction. Recent results on obese and non-obese rats showed remission of type 2 diabetes symptoms within few days after the surgery. The aim of the present work was to analyze the mechanisms of neuro-hormonal regulation responsible for early normalization of metabolic syndrome after bariatric surgery. In present study the concentration of selected intestinal hormones and adipokines in blood plasma and gastrointestinal tissues were analyzed. Study was conducted on Wistar rats. Animals were divided into three groups (each n=6): control (SH) shame-operated rats; animals in which visceral fat tissue was extracted (LP); and rats in which Scopinaro bariatric surgery was performed (BPD). Immunochemistry analysis of blood plasma showed decrease of insulin concentration in BPD and LP and increase of polypeptide YY (PYY) in BPD group as compared to the control. In duodenal mucosa homogenates the tendency to reduce insulin in LP and BPD group, and increase PYY and visfatin in BPD group was observed. Histometry analysis showed reduction of mucosa thickness in excluded segments of gastrointestinal tract in BPD group as compared to the SH and LP. Concluding, model studies on rats allowed better understanding of mechanisms important for early normalization of glycemic index and insulin resistance reduction in rats.

New renin inhibitors with hydrophilic C-terminus.

Four new peptide-based renin inhibitors, Boc-Phe(4-OMe)-MePhe-AHPPA-epsilon Ahx-EA (11), Boc-Phe(4-OMe)-MeLeu-AHP-PA-epsilon Ahx-EA (15), Boc-Phe(4-OMe)-MePhe-Sta-epsilon Ahx-EA (20) and Boc-Phe(4-OMe)-MeLeu-Sta-epsilon Ahx-EA (21) have been synthesized in search of structures with improved biological properties. They were designed as compounds with moderate hydrophobicity (5.28, 4.79, 4.79 and 4.30), respectively. All synthesized inhibitors were resistant to chymotrypsin activity, all were poorly soluble in buffers pH 2.0 and pH 7.4. The inhibitory potency of renin activity in vitro of 11, 15, 20 and 21 expressed as IC50 was 7.0 x 10(-4), 7.5 x 10(-5), 6.0 x 10(-4) and 2.5 x 10(-4) M/l, respectively.

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 2: Derivatives of Gly, Ala, Leu, Pro, Trp, Phe(4 Cl), Ala(alpha-Me).

Fourteen amides of N-substituted natural and anatural amino acids have been designed and synthesized as potential anticonvulsants. They were evaluated in the maximal electroshock seizure (MES) test, the subcutaneous Metrazol seizure threshold (sc Met) test and the rotorod neurotoxicity (Tox) test. According to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) eight of synthesized compounds received class I, two class II and four class III. One of the compounds classified in class I (18) was tested quantitatively after i.p. administration in mice. It showed MES ED50 = 67.41 mg/kg and protective index (PI) = 4.5. Conformational models of the synthesized compounds were compared to one another, as well as to models of some standard compounds.

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 1: alanine derivatives.

Fifteen amides of N-substituted D-Ala, DL-Ala and beta Ala have been designed and synthesized as potential anticonvulsants. All obtained amides as well as one intermediate (8) were evaluated in the maximal electroshock seizure (MES) test, the subcutaneous Metrazol seizure threshold (sc Met) test and the rotorod neurotoxicity (Tox) test in mice. According to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) eight compounds received class I, three class II and five class III designations. Two of the most active compounds (20, 24) were tested quantitatively. They exhibited, after i.p. administration in mice, a large protective index (PI) 3.2 for 20 and 4.3 for 24 and after oral administration in rat PI > 18 for 20 and > 14 for 24.

Renin inhibitors containing nicotinic or isonicotinic acid at the N-terminus. Part V.

Four new compounds: Nic-Phe/4-OMe/-MePhe-Sta-epsilonAhx-OMe/23/,Nic-Phe/4-OMe/-MePhe- Sta-epsilonAhx-Iaa/24/,iNic-Phe/4-OMe/-MeLeu-Sta-ep silonAhx-OMe/29/ and iNic-Phe/4-OMe/-MeLeu-Sta-epsilonAhx-Iaa/30/ have been synthesized in search after renin inhibitors of improved biological properties. Their stability against chymotrypsin activity, solubility in water at pH 7.4, 6.9 and 2.0, partition coefficient and activity in vitro were determined. All synthesized inhibitors are resistant to enzymatic degradation, all are very good soluble in water at pH 2.0, poorly soluble at pH 6.9 and insoluble at pH 7.4. Partition coefficients go up together with increase of pH worth of buffer. IC50 of obtained inhibitors 23,24,29 and 30 is 3 x 10(-4),7.5 x 10(-4),4 x 10(5) and 4 x 10(-3)M/1 respectively.

Enzymatically stable renin inhibitors containing statine and 6 aminohexanoic acid. Part IV.

Eight new peptide renin inhibitors: Boc-Phe/4-OMe/His-Sta-epsilonAhx-Iaa(13), Boc-Phe/4-OMe/-His-Sta-episilonAhx-OMe,(21),Boc-Phe/4-OMe/-MePhe-S ta-epsilonAhx-Iaa(27),Boc-Phe/4-OMe/-MePhe-Sta-epsilonAhx-++ +epsilonAhx-Iaa(32),Boc-Phe/4-OMe/-MePhe-Sta-Val-epsilonAhx- OMe (38),Boc-Phe/4-OMe/-MeVal-Sta-Val-Iaa(48),Boc-Phe/4-OMe/-Me Val-Sta-Iaa(51), Boc-Phe/4-OMe/-MeLeu-Sta-epsilonAhx-Iaa (57) have been synthesized in search after compounds of improved biological properties. All peptides were obtained by carbodimide method in solution by stepwise elongation of the peptide chain or by fragment condensation. Their potency was assayed in vitro by a spectrofluorometric method/assay of Leu-Val-Tyr-Ser released from N-acetyltetradecapeptide substrate by renin in the presence of an inhibitor/. Their resistance to enzymatic degradation was assayed by determination of stability to chymotrypsin activity. The most potent inhibitor was (13):IC50 = 7 x 10(-8)M/1. All inhibitors were stable to chymotrypsin.