Physicochemical quality assessment of various brands of paracetamol tablets sold in Freetown Municipality.

Paracetamol is a widely used over-the-counter drug for managing fever and pain, but its quality may vary among different brands, especially in low- and middle-income countries, where counterfeit and substandard medicines are prevalent. This study evaluated the physicochemical properties of fifteen brands of 500 mg paracetamol tablets sold in various pharmacies in Freetown, Sierra Leone using identification tests, friability tests, assay, dissolution tests, and mass variation. The results showed that three brands were not registered with the Pharmacy Board of Sierra Leone, and two brands did not meet the requirement for labelling (no manufacturing date).

An aryl dioxygenase shows remarkable double dioxygenation capacity for diverse bis-aryl compounds, provided they are carbocyclic.

The bacterial dioxygenation of mono- or polycyclic aromatic compounds is an intensely studied field. However, only in a few cases has the repeated dioxygenation of a substrate possessing more than a single aromatic ring been described. We previously characterized the aryl-hydroxylating dioxygenase BphA-B4h, an artificial hybrid of the dioxygenases of the biphenyl degraders Burkholderia xenovorans LB400 and Pseudomonas sp.

Flavonoid glycosides from Olax mannii: Structure elucidation and effect on the nuclear factor kappa B pathway.

Ethnopharmacological Relevance: Olax mannii Oliv. (Olacaceae) is among the many medicinal plants used in Nigeria for the ethnomedicinal management of both cancer and inflammation. Such plants represent potential sources of innovative therapeutic agents for the treatment of cancer and other malignant disorders.

Permissivity of the biphenyl-specific aerobic bacterial metabolic pathway towards analogues with various steric requirements.

It has repeatedly been shown that aryl-hydroxylating dioxygenases do not possess a very high substrate specificity. To gain more insight into this phenomenon, we examined two powerful biphenyl dioxygenases, the well-known wild-type enzyme from Burkholderia xenovorans LB400 (BphA-LB400) and a hybrid enzyme, based on a dioxygenase from Pseudomonas sp. B4-Magdeburg (BphA-B4h), for their abilities to dioxygenate a selection of eight biphenyl analogues in which the second aromatic ring was replaced by aliphatic as well as aliphatic/aromatic moieties, reflecting a variety of steric requirements.

Callyaerins from the Marine Sponge Callyspongia aerizusa: Cyclic Peptides with Antitubercular Activity.

Chemical investigation of the Indonesian sponge Callyspongia aerizusa afforded five new cyclic peptides, callyaerins I-M (1-5), along with the known callyaerins A-G (6-12). The structures of the new compounds were unambiguously elucidated on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. In addition, the structures of callyaerins D (9), F (11), and G (12), previously available in only small amounts, have been reinvestigated and revised.

Biotransformation of phloretin by amylosucrase yields three novel dihydrochalcone glucosides.

Glycosylation is one of the most important tailoring reactions for natural products. It typically exerts profound direct or indirect effects on their biological activity. The dihydrochalcone phloretin and its known sugar derivatives, particularly phlori(d)zin, have been shown to influence various cellular processes.

Flavonoid glucosylation by non-Leloir glycosyltransferases: formation of multiple derivatives of 3,5,7,3',4'-pentahydroxyflavane stereoisomers.

Flavonoids are known to possess a multitude of biological activities. Therefore, diversification of the core structures is of considerable interest. One of nature's important tailoring reactions in the generation of bioactive compounds is glycosylation, which is able to influence numerous molecular properties.

New nitrogenous compounds from a Red Sea sponge from the Gulf of Aqaba.

Chemical investigation of an unknown marine sponge, which was collected in the Gulf of Aqaba (Jordan), afforded a new brominated alkaloid 3-amino-1-(2-amino-4-bromophenyl)propan-1-one (1), as well as 7-bromoquinolin-4(1H)-one (2) which had previously only been reported as a synthetic compound. In addition, caulerpin (6), previously only known to be produced by algae, was likewise isolated. Furthermore, three known alkaloids including (Z)-5-(4-hydroxybenzylidene)-hydantoin, (Z)-6-bromo-3'-deimino-2',4'-bis(demethyl)-3'-oxoaplysinopsin, and 6-bromoindole-3-carbaldehyde (3-5), were also obtained.

Isolation of dimeric, trimeric, tetrameric and pentameric procyanidins from unroasted cocoa beans (Theobroma cacao L.) using countercurrent chromatography.

The main procyanidins, including dimeric B2 and B5, trimeric C1, tetrameric and pentameric procyanidins, were isolated from unroasted cocoa beans (Theobroma cacao L.) using various techniques of countercurrent chromatography, such as high-speed countercurrent chromatography (HSCCC), low-speed rotary countercurrent chromatography (LSRCCC) and spiral-coil LSRCCC. Furthermore, dimeric procyanidins B1 and B7, which are not present naturally in the analysed cocoa beans, were obtained after semisynthesis of cocoa bean polymers with (+)-catechin as nucleophile and separated by countercurrent chromatography.

Production, Structural Elucidation, and In Vitro Antitumor Activity of Trehalose Lipid Biosurfactant from Nocardia farcinica Strain.

The objective of this study was to isolate and identify the chemical structure of a biosurfactant produced by Nocardia farcinica strain BN26 isolated from soil, and evaluate its in vitro antitumor activity on a panel of human cancer cell lines. Strain BN26 was found to produce glycolipid biosurfactant on n-hexadecane as the sole carbon source. The biosurfactant was purified using medium-pressure liquid chromatography and characterized as trehalose lipid tetraester (THL) by nuclear magnetic resonance spectroscopy and mass spectrometry.

Trehalose lipid biosurfactants produced by the actinomycetes Tsukamurella spumae and T. pseudospumae.

Actinomycetales are known to produce various secondary metabolites including products with surface-active and emulsifying properties known as biosurfactants. In this study, the nonpathogenic actinomycetes Tsukamurella spumae and Tsukamurella pseudospumae are described as producers of extracellular trehalose lipid biosurfactants when grown on sunflower oil or its main component glyceryltrioleate. Crude extracts of the trehalose lipids were purified using silica gel chromatography.

Trimeric anthracenes from the endophytic fungus Stemphylium globuliferum.

The first naturally occurring trimeric anthracene derivatives, stemphylanthranols A and B (1 and 2), were obtained from the endophytic fungus Stemphylium globuliferum that had been isolated from Juncus actus growing in Egypt. The structures of the new compounds were unambiguously determined by 1D and 2D NMR, and by HRMS. A hypothetical biosynthetic pathway for the new trimers is proposed.

Semisynthetic preparation and isolation of dimeric procyanidins B1-B8 from roasted hazelnut skins (Corylus avellana L.) on a large scale using countercurrent chromatography.

Dimeric procyanidins B1-B8 were produced via semisynthesis from a polymeric proanthocyanidin fraction of hazelnut skins (Corylus avellana L.). This polymeric fraction was found to consist mostly of (+)-catechin and (-)-epicatechin as upper units.

Balticidins A-D, antifungal hassallidin-like lipopeptides from the Baltic Sea cyanobacterium Anabaena cylindrica Bio33.

Balticidins A-D (1-4), four new antifungal lipopeptides, were isolated from the laboratory-cultivated cyanobacterium Anabaena cylindrica strain Bio33 isolated from a water sample collected from the Baltic Sea, Rügen Island, Germany. Fractionation of the 50% aqueous MeOH extract was performed by bioassay-guided silica gel column chromatography followed by SPE and repeated reversed-phase HPLC. The main fraction containing the compounds exhibited a strong and specific antifungal activity with inhibition zones in an agar-diffusion assay from 21 to 32 mm against Candida albicans, Candida krusei, Candida maltosa, Aspergillus fumigatus, Microsporum gypseum, Mucor sp.

Structure of a novel farnesylated bilin from an insect--formation by α-cleavage of heme A of mitochondrial cytochrome c oxidases?

Biliproteins are present in almost all forms of life, and many of them play vital roles in photobiology. The bilin ligand of a recently characterized 500-kDa biliprotein from an insect has been isolated and its structure elucidated with chemical and spectroscopic techniques (UV-visible, IR, MS, NMR, and CD). This blue pigment, named CV-bilin, represents a unique high molecular mass derivative of biliverdin IXα, with an unusual 10E-configuration and a molecular mass of 852 Da, corresponding to C48H60N4O10.

Structure elucidation and characterization of microbial 2-tridecyl sophorosides (biosurfactants).

To produce novel types of sophorose lipids containing an odd number of carbon atoms in the lipophilic moiety, Candida bombicola ATCC 22214 was grown in 500-ml flask cultures with glucose as main carbon source, and additionally, 2-tridecanone as co-substrate. After solvent extraction, the crude product mixture was separated into pure fractions, and each fraction was analysed via NMR and mass spectroscopy. This effective strategy generated five new glycolipids, 2-tridecyl sophorosides, which differed in the number of glucose units, and acetyl and hydroxy groups, respectively.

Cytotoxic and protein kinase inhibiting nakijiquinones and nakijiquinols from the sponge Dactylospongia metachromia.

Chemical investigation of the sponge Dactylospongia metachromia afforded five new sesquiterpene aminoquinones (1-5), two new sesquiterpene benzoxazoles (6 and 7), the known analogue 18-hydroxy-5-epi-hyrtiophenol (8), and a known glycerolipid. The structures of all compounds were unambiguously elucidated by one- and two-dimensional NMR and by MS analyses, as well as by comparison with the literature. Compounds 1-5 showed potent cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values ranging from 1.

Identification of two novel Prodelphinidin A-type dimers from roasted hazelnut skins ( Corylus avellana L.).

Two new A-type dimeric prodelphinidins, EGC-(2β→O7, 4β→8)-C and EGC-(2β→O5, 4β→6)-C, were isolated from the skins of roasted hazelnut ( Corylus avellana L.) by low-speed rotary countercurrent chromatography (LSRCCC) and final purification by preparative HPLC. Their structures were determined by a combination of mass spectrometry (HPLC-ESI-MS(n) and HR-ESI-MS) and NMR spectroscopy that included the application of 2D methods ((1)H-(1)H COSY, HSQC, HMBC, and NOESY).