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Thermal analysis of pharmaceutical compounds

III. Characterization of sulphonamides by thermal analysis

Authors: F. I. Khattab, N. Y. M. Hassan and M. M. Amer

Fourteen sulphonamides have been thermally analyzed using thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). Their thermal reactions and stabilities have been thoroughly studied. It was found that the sulphonamides are first transformed into sulphanilamide. The melting points of these sulphonamides have been determined through their DTA curves and by the Kofler microscope, the results agreeing with those reported in the literature. The amount of water of crystallization has been calculated from the TG and DTG curves. Analysis of mixtures of some sulphonamides has been achieved by thermal analysis and by thin-layer chromatography using different solvent systems.

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The space available to plants affects the available resources and hence modifies the growth habits and yield potential of plants. The effect of four seeding densities (250, 500, 750 and 1000 viable seeds/m2) and three row spacings (12, 15 and 20 cm) were evaluated at Morfa Mawr field station at the University of Wales, Aberystwyth, UK during the 1993 and 1994 growing seasons. Number of capsules per plant, number of seeds per capsule, thousand-seed weight and seed yield were examined during the study. Capsule index (CI) and harvest index (HI) were calculated from the observed data. During the first year, capsules per plant, seeds per capsule and capsule index were increased by decreasing the seed density, while the maximum seed yield of 3.9 t/ha was recorded at the highest seed density of 1000 seeds/m2. An increase in row spacing led to an almost linear increase in most of the yield attributes of the crop. During the second year, the response of yield and yield attributes to seeding densities was similar to that recorded during the first year. Seed yield increased with decreasing row spacing, while the rest of the components did not show any consistent response. During the first year, the overall performance and production of the crop was higher than in the second year because of the better weather conditions, with mild temperature and high rainfall during the season.

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The laelapid mites Cosmolaelaps keni and Laelaspis astronomicus beside the rhodacarid mite Protogamasellopsis denticus are biological control agents and being native predators in Egypt. In order to raise active population of above species, the biology and demographic parameters, of the three tested species were observed under laboratory conditions with eggs of Ephestia kuhniella. All predatory species were developed and reproduced with E. kuhniella eggs. The mean developmental and oviposistion periods of L. astronomicus females were the longest from the other tested species. The mean longevity of C. keni was longer than that of P. denticus. Cosmolaelaps keni consumed more E. kuhniella eggs during the oviposition and adult longevity periods than other species did. Protogamasellopsis denticus fed on E. kuhniella food gave the most rate of oviposition as shown by the maximum fertility, net reproductive rate and gross reproductive rate. Laelaspis astronomicus preying on E. kuhniella eggs gave the longest generation time, lowest rate of fecundity and all life table parameters compared to other tested species; therefore E. kuhniella eggs was appropriate for the oviposition of P. denticus and C. keni rather than L. astronomicus.

This study is the first to report that E. kuhniella eggs were an acceptable factitious food for P. denticus, L. astronomicus and C. keni.

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The predatory mites Neoseiulus barkeri, Amblyseius swirskii and Cydnoseius negevi are native phytoseiid mites in Egypt. The biology of these predators was studied using Achroia grisella eggs as food source. Tested phytoseiids were succeeded to develop to adulthood and sustain oviposition on A. grisella eggs. For Cydnoseius negevi, the development was slower and fecundity was lower than for Neoseiulus barkeri and Amblyseius swirskii. The predation rate during immature stages of Cydnoseius negevi was higher than those of Neoseiulus barkeri and Amblyseius swirskii. During oviposition period, N. barkeri consumed more eggs than other phytoseiids did. The higher mean fecundity was recorded for Neoseiulus barkeri and Amblyseius swirskii as opposed to the lower mean for Cydnoseius negevi. When Amblyseius swirskii fed on Achroia grisella eggs, the oviposition period, female longevity and mean generation time were longer than for Cydnoseius negevi and Neoseiulus barkeri. Feeding on eggs of Achroia grisella resulted in the lowest mean fecundity, net reproductive rate, intrinsic rate of natural increase, finite rate of increase and gross reproductive rate for Cydnoseius negevi. The sex ratio of all predators' progeny was in female-biased. Consequently, the moth egg was alternative food for Neoseiulus barkeri and Amblyseius swirskii, while it considers as survival prey for Cydnoseius negevi.

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Authors: Omar M. Khalaf, Mosad A. Ghareeb, Amal M. Saad, Hassan M. F. Madkour, Ahmed K. El-Ziaty and Mohamed S. Abdel-Aziz

Different solvent extracts of the aerial parts of Senna italica (Mill.) were investigated for their chemical constituents and biological activities. Moreover, bio-guided fractionation led to isolation and identification of six compounds, namely: physcion (1), emodin (2), 2-methoxy-emodin-6-O-β-d-glucopyranoside (3), 1-hydroxy-2-acetyl-3-methyl-6-hydroxy-8-methoxynaphthalene (tinnevellin) (4), quercetin 3-O-α-l-rhamnopyranosyl-(1→6)-β-d-glucopyranoside (rutin) (5), and 1,6,8-trihydroxy-3-methoxy-9,10-dioxo-9,10-dihydroanthracene (6). The chemical structures of these compounds were established via 1D and 2D 1H- and 13C-NMR spectroscopy. Ethyl acetate and n-butanol extracts as well as compound 3 were evaluated for their anticancer activity against tumor cell lines. The tested extracts showed a moderate to weak activity, while compound 3 showed a moderate activity against human liver cancer (Hep G2) and breast cancer (MCF-7) cell lines with IC50 values of 57.5 and 42.3 μg/mL, respectively. Both ethyl acetate and n-butanol extracts exhibited antimicrobial activities with different strengths, i.e., ethyl acetate exhibited antimicrobial activity against seven test microbes while n-butanol extract showed antimicrobial activity against all tested microbes. This is the first report for the isolation of compound 3 as a new compound from S. italica growing in Egypt.

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