The anthranoid skeleton is believed to be formed by octaketide synthase (OKS), a member of the type III polyketide synthase (PKS) superfamily. Recombinant OKSs catalyze stepwise condensation of eight acetyl units to form a linear octaketide intermediate which, however, is incorrectly folded and cyclized to give the shunt products SEK4 and SEK4b. Here we report in vitro formation of the anthranoid scaffold by cell-free extracts from yeast-extract-treated Cassia bicapsularis cell cultures. Unlike field- and in vitro-grown shoots which accumulate anthraquinones, cell cultures mainly contained tetrahydroanthracenes, formation of which was increased 2.5-fold by the addition of yeast extract. The elicitor-stimulated accumulation of tetrahydroanthracenes was preceded by an approx. 35-fold increase in OKS activity. Incubation of cell-free extracts from yeast-extract-treated cell cultures with acetyl-CoA and [2-14C]malonyl-CoA led to formation of torosachrysone (tetrahydroanthracene) and emodin anthrone, beside two yet unidentified products. No product formation occurred in the absence of acetyl-CoA as starter substrate. To confirm the identities of the enzymatic products, cell-free extracts were incubated with acetyl-CoA and [U-13C3]malonyl-CoA and 13C incorporation was analyzed by ESI-MS/MS. Detection of anthranoid biosynthesis in cell-free extracts indicates in vitro cooperation of OKS with a yet unidentified factor or enzyme for octaketide cyclization.

A phytochemical study of Geosmithia lavendula Pitt led to the isolation of three new anthraquinones: 1-acetyl-2,4,6,8-tetrahydroxy-9,10-anthraquinone (1), 2-acetyl-1,4,5,7-tetrahydroxy-9,10-anthraquinone (2), and 1-acetyl-2,4,5,6,7-pentahydroxy-9,10-anthraquinone (3), as well as another new compound named didodecyl thiodipropionate (propionic acid, 3,3-sulfinyl di-1,1'-didodecyl ester) (4), along with ten known compounds: 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone (rhodolamprometrin) (5), 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone (6), (22E)-ergosta-6,22-diene-3β,5α,8α-triol, p-hydroxybenzyl alcohol, oleic acid, D-mannitol, palmitic acid, stearic acid, cis-vaccenic acid and 2-decenal. The structures of the isolated metabolites were elucidated based on NMR spectroscopic and mass spectrometric data. Compound 1 exhibited moderate activity against methicillin resistant Staphylococcus aureus with an IC50 value of 16.1 μg/mL.

A phytochemical study of Geosmithia lavendula Pitt led to the isolation of three new anthraquinones: 1-acetyl-2,4,6,8-tetrahydroxy-9,10-anthraquinone (1), 2-acetyl-1,4,5,7-tetrahydroxy-9,10-anthraquinone (2), and 1-acetyl-2,4,5,6,7-pentahydroxy-9,10-anthraquinone (3), as well as another new compound named didodecyl thiodipropionate (propionic acid, 3,3-sulfinyl di-1,1'-didodecyl ester) (4), along with ten known compounds: 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone (rhodolamprometrin) (5), 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone (6), (22E)-ergosta-6,22-diene-3β,5α,8α-triol, p-hydroxybenzyl alcohol, oleic acid, D-mannitol, palmitic acid, stearic acid, cis-vaccenic acid and 2-decenal. The structures of the isolated metabolites were elucidated based on NMR spectroscopic and mass spectrometric data. Compound 1 exhibited moderate activity against methicillin resistant Staphylococcus aureus with an IC50 value of 16.1 μg/mL.

A phytochemical study of Geosmithia lavendula Pitt led to the isolation of three new anthraquinones: 1-acetyl-2,4,6,8-tetrahydroxy-9,10-anthraquinone (1), 2-acetyl-1,4,5,7-tetrahydroxy-9,10-anthraquinone (2), and 1-acetyl-2,4,5,6,7-pentahydroxy-9,10-anthraquinone (3), as well as another new compound named didodecyl thiodipropionate (propionic acid, 3,3-sulfinyl di-1,1'-didodecyl ester) (4), along with ten known compounds: 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone (rhodolamprometrin) (5), 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone (6), (22E)-ergosta-6,22-diene-3β,5α,8α-triol, p-hydroxybenzyl alcohol, oleic acid, D-mannitol, palmitic acid, stearic acid, cis-vaccenic acid and 2-decenal. The structures of the isolated metabolites were elucidated based on NMR spectroscopic and mass spectrometric data. Compound 1 exhibited moderate activity against methicillin resistant Staphylococcus aureus with an IC50 value of 16.1 μg/mL.

A phytochemical study of Geosmithia lavendula Pitt led to the isolation of three new anthraquinones: 1-acetyl-2,4,6,8-tetrahydroxy-9,10-anthraquinone (1), 2-acetyl-1,4,5,7-tetrahydroxy-9,10-anthraquinone (2), and 1-acetyl-2,4,5,6,7-pentahydroxy-9,10-anthraquinone (3), as well as another new compound named didodecyl thiodipropionate (propionic acid, 3,3-sulfinyl di-1,1'-didodecyl ester) (4), along with ten known compounds: 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone (rhodolamprometrin) (5), 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone (6), (22E)-ergosta-6,22-diene-3β,5α,8α-triol, p-hydroxybenzyl alcohol, oleic acid, D-mannitol, palmitic acid, stearic acid, cis-vaccenic acid and 2-decenal. The structures of the isolated metabolites were elucidated based on NMR spectroscopic and mass spectrometric data. Compound 1 exhibited moderate activity against methicillin resistant Staphylococcus aureus with an IC50 value of 16.1 μg/mL.

Nalidixic acid is practically insoluble in water therefore the aim of this study was to study the effect of both cosolvency and solid dispersionon its solubility. Among different cosolvents, the highest result was achieved by isopropanol (30% v/v). Through all studied solid dispersioncarriers in the ratio 1:1, sodium benzoate enhanced both the solubility and antibacterial activity of nalidixic acid and was therefore selected for further investigation. Increasing sodium benzoate ratio had significantly increased nalidixic acid solubility till a 1:8 ratio. Differential scanning calorimetry (DSC) showed a sharp endothermic peak of nalidixic acid which was slightly shifted to lower temperature accompanied by significant broadening in the case of solid dispersion. Further confirmation was obtained by X-ray powder diffraction (XRPD) whereas the peak heights were much reduced in the case of solid dispersion confirming the cause of increasing solubility.

Nalidixic acid is practically insoluble in water therefore the aim of this study was to study the effect of both cosolvency and solid dispersionon its solubility. Among different cosolvents, the highest result was achieved by isopropanol (30% v/v). Through all studied solid dispersioncarriers in the ratio 1:1, sodium benzoate enhanced both the solubility and antibacterial activity of nalidixic acid and was therefore selected for further investigation. Increasing sodium benzoate ratio had significantly increased nalidixic acid solubility till a 1:8 ratio. Differential scanning calorimetry (DSC) showed a sharp endothermic peak of nalidixic acid which was slightly shifted to lower temperature accompanied by significant broadening in the case of solid dispersion. Further confirmation was obtained by X-ray powder diffraction (XRPD) whereas the peak heights were much reduced in the case of solid dispersion confirming the cause of increasing solubility.

The aim of this work was to formulate and evaluate nalidixic acid for the first time in different topical ointment bases. Among different ointment formulations, hydrocarbon base achieved the lowest release, while water-soluble base achieved the highest release. The presence of both isopropanol as cosolvent and nalidixic acid-sodium benzoate solid dispersion in formula (W8) enhanced both the release and the antibacterial activity of nalidixic acid compared to ointment formula (W5) containing neither of them. A stability study was also performed where no significant change in pH or drug content was observed in all stored formulations (W5 and W8). Stability was further checked by thin-layer chromatography (TLC). After clinical application in impetigo, it was found that the presence of isopropanol and nalidixic acid-sodium benzoate solid dispersion in ointment formulation (W8) caused a significant reduction in the mean time of healing (only four days) in impetigo patients.

The aim of this work was to formulate and evaluate nalidixic acid for the first time in different topical ointment bases. Among different ointment formulations, hydrocarbon base achieved the lowest release, while water-soluble base achieved the highest release. The presence of both isopropanol as cosolvent and nalidixic acid-sodium benzoate solid dispersion in formula (W8) enhanced both the release and the antibacterial activity of nalidixic acid compared to ointment formula (W5) containing neither of them. A stability study was also performed where no significant change in pH or drug content was observed in all stored formulations (W5 and W8). Stability was further checked by thin-layer chromatography (TLC). After clinical application in impetigo, it was found that the presence of isopropanol and nalidixic acid-sodium benzoate solid dispersion in ointment formulation (W8) caused a significant reduction in the mean time of healing (only four days) in impetigo patients.

A new, simple, and stability indicating thin layer chromatographic (TLC) method has been developed for estimation of norfloxacin. Study was performed on precoated silica gel F254 TLC plate using environmentally safe mobile phase consisting of n-butanol : methanol : ammonia (33%) (8:1:3.5 v/v). A Camag TLC Scanner 3 set at 282 nm was used for direct determination of the chromatograms in the reflectance / absorbance mode. Method was validated according to ICH guidelines. Determination coefficient of the calibration curve was 0.9962 in the range 6–150 ng/band with limit of detection and limit of quantification of 1.01 ng/band and 3.06 ng/band, respectively. Statistical comparison of the results with those of the official HPLC method showed good agreement between the official and the proposed methods with respect to accuracy and precision. Norfloxacin was subjected to forced degradation at 150°C with 2M HCl or 2M NaOH, and the degradation rate in both cases was studied. The calculated first order rate constant for the degradation were determined at 0.056 and 0.023 hour1 and the t½ were 12.28 and 30.09 hr for acid and base degradation, respectively. The method has the potential to determine norfloxacin in different dosage forms and in quality control laboratories.