A series of pyrazine-2-carboxylic acid hydrazide derivatives were synthesized and screened for their activity against Mycobacterium tuberculosis. The results show that pyrazine-2-carboxylic acid hydrazide-hydrazone derivatives 3a-l were less active than pyrazinamide. In contrast, the N4-ethyl-N1-pyrazinoyl-thiosemicarbazide 4 showed the highest activity against M. tuberculosis H37Rv (IC90 = 16.87 µg/ mL). Details of the structure-activity and structure-cytotoxicity relationships are discussed.

We previously reported potent BACE1 inhibitors KMI-420 and KMI-570 possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. Acidic moieties at the P'1 and P4 positions of KMI inhibitors are thought to be unfavorable in terms of membrane permeability across the blood-brain barrier. Herein, we replaced acidic moieties at the P4 position with hydrogen bond accepting groups and acidic moieties at the P'1 position with less acidic and similar molecular-size moieties (carboxylic acid or tetrazole bioisosteres). These inhibitors exhibited improved BACE1 inhibitory activities and a thorough quantitative structure–activity relationship study was performed.

A new long chain fatty alcohol acetate identified as 17-hydroxypentacosanyl acetate (1), together with a new xanthone identified as 1,8-dihydroxy-3,6-dimethoxy-xanthone-5-O-[-L-rhamnopyranosyl-(1"2')]--D-glycopyranoside (3), as well as two new lignans identified as (+)-lyoniresinol-3a-O-[-L-rhamnopyranosyl-(1"'6")]--D-glucopyranoside (4) and (+)-isolariciresinol-3a-O-[-L-rhamnopyranosyl-(1"'2")--L-rhamnopyranosyl-(1""6")--D-glucopyranoside (5), in addition to -sitosterol-3-O-acetate (2) were isolated from the methanolic extract of the aerial parts of Polygonum bellardii growing in Egypt. Their structures were elucidated on the basis of different chemical and spectroscopic evidences. The total extract and its fractions, in addition to compounds (3, 4 and 5) showed significant antioxidant potential by DPPH• scavenging activity technique.

A new long chain fatty alcohol acetate identified as 17-hydroxypentacosanyl acetate (1), together with a new xanthone identified as 1,8-dihydroxy-3,6-dimethoxy-xanthone-5-O-[-L-rhamnopyranosyl-(1"2')]--D-glycopyranoside (3), as well as two new lignans identified as (+)-lyoniresinol-3a-O-[-L-rhamnopyranosyl-(1"'6")]--D-glucopyranoside (4) and (+)-isolariciresinol-3a-O-[-L-rhamnopyranosyl-(1"'2")--L-rhamnopyranosyl-(1""6")--D-glucopyranoside (5), in addition to -sitosterol-3-O-acetate (2) were isolated from the methanolic extract of the aerial parts of Polygonum bellardii growing in Egypt. Their structures were elucidated on the basis of different chemical and spectroscopic evidences. The total extract and its fractions, in addition to compounds (3, 4 and 5) showed significant antioxidant potential by DPPH• scavenging activity technique.

The chloroformic fraction of the roots of Centaurium spicatum L. afforded one new xanthone named 1,5,8-trihydroxy-3,6,7-trimethoxyxanthone (1) together with six known xanthones (2–7), one of them isolated for the first time from a plant source (2). One secoiridoid glucoside (8) was also isolated. The structures of the isolated compounds were established based on 1D and 2D (1H–1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated compounds were tested for their antimicrobial and antiprotozoal activities. Compound 6 displayed moderate antifungal activity against Candida krusei and Cryptococcus neoformans with IC50 values of 12.8 and 17.9 g/ml respectively.

Two new acetylated flavonol glycosides, quercetin 3-O-[(2,4-diacetyl--L-rhamnopyranosyl)-(16)]-2,4-diacetyl--D-galactopyranoside (1) and quercetin 3-O-[(2,4-diacetyl--L-rhamnopyranosyl)-(16)]-3,4-diacetyl--D-galacto-pyranoside (2), in addition to two known acetylated quercetin glycosides quercetin 3-O-[(2,3,4-triacetyl--L-rhamnopyranosyl)-(16)--D-galactopyranoside (3) and quercetin 3-O-[(2,3,4-triacetyl--L-rhamnopyranosyl)-(16)-3-acetyl--D-galactopyranoside (4), were isolated from the aerial part of Centaurium spicatum (L.) Fritsch (Gentianaceae). Structure elucidation, especially the localization of the acetyl groups, and complete 1H- and 13C-NMR assignments of these biologically active compounds were carried out using one- and two-dimensional NMR measurements, including 1H- and 13C-NMR, DEPT-135, H–H COSY, HMQC and HMBC, in addition to HR-FAB/MS experiments.

The current work is concerned with synthesis of new 1,2,4-traizoles, 1,3,4-thiadiazoles, and 1,3,4-thiadiazines derivatives. Derivatives 3a-i were obtained by condensation of 4-amino-3-(4-pyridine)-5-mercapto-1,2,4-triazole 1 with the appropriate aldehyde. Compounds 4a-i were synthesized in a one pot reaction involving compounds 3a-i, formaldehyde and morpholine. Condensation of compound 1 with the appropriate acids 4-substituted phenacyl bromide gave compounds 6a-d and 8a-f respectively. The chemical structures of the newly synthsized derivatives were elucidated using different spectral and elemental methods of analyses. All compounds were evaluated for their anti-inflammatory activity and the most potent derivatives were tested for their analgesic activity using indomethacin as a reference drug. In addition, ulcerogenicity and LD50 for the most active compounds were evaluated. Moreover, The antibacterial activities of the newly synthesized derivatives were investigated.

A series of 1,4-disubstituted octahydroquinoxaline-2,3-dione derivatives was prepared through two steps reaction. The latter involves the formation of N,N-disubstituted cyclohexane-1,2-diamine derivatives (1a-j) through reductive alkylation of 1,2-cyclohexanediamine with different aldehydes in presence of sodium cyanoborohydride. Fusion of compounds (1a-j) with diethyl oxalate affording the target compounds (2a-j). Elucidation of structures of compounds (2a-j) was based upon different spectral data as well as the elemental methods of analyses. In addition, mass spectrometry and X-ray diffraction analyses were carried out. Moreover, the lipophilicity of the target compounds as expressed from the Clog P. Most of the test compounds (2a-j) showed weak to moderate antibacterial and antifungal activities against most of the used bacterial and fungal strains in comparison to chloramphenicol and clotrimazole as reference drugs respectively.

Introduction: Earthworms are the major biomass in soil. They have been widely used in traditional Chinese medicine for a long time. However, in the past few decades with the development of biochemical technologies the research on the pharmaceutical effects of earthworms has been commencement. Aims: Experiments were conducted to recognize the therapeutic properties such as anti-inflammatory, antipyretic and antioxidant activities of biologically active extract isolated from two species of earthworm (Pheretima hawayana Rosa and Allolobophora caliginosa Savigny). Materials and methods: Inflammation in the hind paw of albino rat (Rattus rattus) was induced by histamine, pyrexia was induced by Escherichia coli in rats and liver damage was induced by injection of rats with CCl4. Anti-inflammatory drug - indomethacin, anti-pyretic drug - paracetamol and antioxidant drug - silymarin plus were used as standard drugs for comparison. Results: Administration of earthworms extract (100 mg/kg) and indomethacin (10 mg/kg), paracetamol (150 mg/kg), silymarin plus (150 mg/kg) as standard drugs reduced and restored to normal the changes that induced by histamine, Escherichia coli and CCl4 in rats. Conclusions: The present study conclude that both extracts of earthworms gave result as anti-inflammatory and anti-pyretic similar to the standard drugs. The extract of the two species showed various responds as antioxidants against CCl4 induced hepatotoxicity.