Synthesis and evaluation of fluorimetric and colorimetric chemosensors for anions based on (oligo)thienyl-thiosemicarbazones

A family of heterocyclic thiosemicarbazone dyes (3a-d) containing thienyl groups has been synthesized, characterized and their chromo-fluorogenic response in acetonitrile in the presence of selected anions studied. Acetonitrile solutions of 3a-d show absorption bands in the 338-425 nm range which are modulated by the groups attached to the thiosemicarbazone moiety. The fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulfate, nitrate, acetate and anions were used in the recognition studies. Only sensing features were observed for fluoride, cyanide, acetate and dihydrogen phosphate anions. Two different chromogenic responses were found, (i) a small shift of the absorption band due to coordination of the anions with the thiourea protons and (ii) the appearance of a new red shifted band due to deprotonation of the receptor. For the latter process changes in the color solutions from pale-yellow to orange-red were observed. Fluorescence studies showed a different emission behavior according to the number of thienyl rings in the π-conjugated bridges. Stability constants for the two processes (complex formation + deprotonation) for receptors 3a-d in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec program. The interaction of 3d with fluoride was also studied through 1H NMR titrations. Semiempirical calculations to evaluate the hydrogen-donating ability of the receptors were also performed.Fundação para a Ciência e a Tecnologia (FCT) , Acções Integradas Luso-Espanholas/CRUP, Generalitat Valenci

Synthesis and evaluation of thiosemicarbazones functionalized with furyl moieties as new chemosensors for anion recognition

A family of heterocyclic thiosemicarbazone dyes (3a-f and 4) containing furyl groups were synthesized in good yields, characterized and their response in acetonitrile in the presence of selected anions was studied. Acetonitrile solutions of 3a-f and 4 show absorption bands in the 335-396 nm range which are modulated by the electron donor or acceptor strength of the heterocyclic systems appended to the thiosemicarbazone moiety. Fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulphate, nitrate, acetate and cyanide anions, were used in recognition studies. From these anions, only sensing features were seen for fluoride, cyanide, acetate and dihydrogen phosphate. Two clearly different chromo-fluorogenic behaviours were observed, (i) a small shift of the absorption band due to the coordination of the anions with the thiourea protons and (ii) the appearance of a new red shifted band due to deprotonation. For the latter effect, a change in the colour solution from pale yellow to purple was observed. Fluorescence studies were also in agreement with the different effects observed in the UV/Vis titrations. In this case, hydrogen bonding interactions were visible through the enhancement of the emission band, whereas deprotonation induced the appearance of a new red-shifted emission. Logarithms of stability constants for the two processes (complex formation + deprotonation) for receptors 3a-f in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec V1.1.18 program. Semi-empirical calculations to evaluate the hydrogen-donating ability of the receptors and a prospective electrochemical characterization of compound 3b in the presence of fluoride were also performed.Fundação para a Ciência e a Tecnologia (FCT), Acções Integradas Luso-espanholas/CRUP, Generalitat Valenciana

Everything That Glitters is Not Gold

Syphilis is a great imitator. A high index of suspicion for infectious etiology of optic neuropathy in HIV patients is essential even if they are well controlled

Analysis of Geographic Variation among Sixteen African Provenances of Faidherbia albida using PCRBased ITS And RAPD Techniques

PCR analysis based on ITS and RAPD were carried out on sixteen provenances of Faidherbia albida currently growing in a provenance trial in semi-arid Baringo district, Kenya. The objectives of the study were: 1. Determination of the phylogenetic relationship among the 16 provenances in order to establish the species centre of origin 2. Determination of extent of genetic diversity in F. albida using PCR markers. ITS data did not produce any consistent regional or geographic pattern. RAPD data produced a dendrogram clearly grouping the provenances into Western, Southern and Eastern African regions. The study revealed the utility of RAPD markers in understanding geographic variation and phylogenetic relationships among Faidherbia albida populations in Africa. Keywords: DNA, Faidherbia albida, genetic diversity, ITS, PCR, provenance, RAPD Discovery and Innovation Vol. 19 (2) 2007: pp. 108-11

The Benefits of East Coast Fever Immunization (Ecfim) in East Coast Fever Disease (EFC) Control in Kenya

East Coast fever immunization (ECFiM) using infection and treatment method (ITM) was done in Kiambu District between 1994 and 1996.an impact assessment was study on ECFiM using a structured questionnaire was carried out in 1998. On 230 farms immunized and 40 control farms, the response by farmers was analysed Using EPI-INFO version 6. A total of 84.3 % of the farmers considered ECFiM to be safe. In ECF immunized farms, spraying of cattle using acaricide has been relaxed from once a week to twice a month. 90.8 % of the farmers who had ECFiM technology and integrated tick control and tick borne disease control will make it possible for the introduction of superior breeds in areas where ECF was a major constraint in Kenya. The Kenya Veterinarian Vol. 22 2001: pp. 63-6

Comparative Genomics, Phylogenetics, Biogeography, and Effects of Climate Change on <i>Toddalia asiatica</i> (L.) Lam. (Rutaceae) from Africa and Asia

In the present study, two samples of Toddalia asiatica species, both collected from Kenya, were sequenced and comparison of their genome structures carried out with T. asiatica species from China, available in the NCBI database. The genome size of both species from Africa was 158, 508 base pairs, which was slightly larger, compared to the reference genome of T. asiatica from Asia (158, 434 bp). The number of genes was 113 for both species from Africa, consisting of 79 protein-coding genes, 30 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes. Toddalia asiatica from Asia had 115 genes with 81 protein-coding genes, 30 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes. Both species compared displayed high similarity in gene arrangement. The gene number, orientation, and order were highly conserved. The IR/SC boundary structures were the same in all chloroplast genomes. A comparison of pairwise sequences indicated that the three regions (trnH-psbA, rpoB, and ycf1) were more divergent and can be useful in developing effective genetic markers. Phylogenetic analyses of the complete cp genomes and 79 protein-coding genes indicated that the Toddalia species collected from Africa were sister to T. asiatica collected from Asia. Both species formed a sister clade to the Southwest Pacific and East Asian species of Zanthoxylum. These results supported the previous studies of merging the genus Toddalia with Zanthoxylum and taxonomic change of Toddalia asiatica to Zanthoxylum asiaticum, which should also apply for the African species of Toddalia. Biogeographic results demonstrated that the two samples of Toddalia species from Africa diverged from T. asiatica from Asia (3.422 Mya, 95% HPD). These results supported an Asian origin of Toddalia species and later dispersal to Africa and Madagascar. The maxent model analysis showed that Asia would have an expansion of favorable areas for Toddalia species in the future. In Africa, there will be contraction and expansion of the favorable areas for the species. The availability of these cp genomes will provide valuable genetic resources for further population genetics and biogeographic studies of these species. However, more T. asiatica species collected from a wide geographical range are required

Traditional Uses, Phytochemistry, and Pharmacological Properties of the Genus <i>Blechnum</i>—A Narrative Review

Blechnum L. is a genus belonging to the Blechnaceae family with 236 accepted species that grow in intertropical, subtropical, and southern temperate regions. Several species of the genus have long been used in folk medicines to treat a broad spectrum of ailments, including typhoid, urinary infections, influenza, wounds, pulmonary complaints, blisters, boils, and antihelmintic-related complications. So far, about 91 chemical compounds have been isolated from different parts of 20 Blechnum species. Among these metabolites, phenolic compounds, sterols, and fatty acids are the main constituents. Modern pharmacological investigations revealed several isolated compounds and extracts to exhibit exceptional biological properties including the antioxidant, antimicrobial, anti-inflammatory, anticancer, insecticidal, antitrematocidal and wound healing. In various tests, both quercetin-7′,3′,4′-trimethoxy and phytol metabolites showed potential antioxidant and antitrematocidal properties, while ponasterone exhibited insecticidal activity. Despite having a broad range of traditional medicinal benefits and biological properties, understanding the scientific connotations based on the available data is still challenging. This article presents a comprehensive review of the traditional uses, phytochemical compounds, and pharmacological aspects of the Blechnum species

A review on the traditional uses, phytochemistry, and pharmacology of the genus Veronicastrum (Plantaginaceae)

Ethnopharmacological relevance: Veronicastrum Heist. ex Fabr. (Plantaginaceae) is a multifunctional plant in China and other parts of the continent. It has traditionally been used in the treatment of ascites, edema, blood stasis, pain relief, chronic nephritis injury, fever, cough, headache, arthritis, dysentery, rheumatism, pleural effusion, liver damage, and other disorders. Although research has confirmed that the genus Veronicastrum contain many active compounds, no review of its traditional uses, phytochemistry or pharmacology has been conducted to date. Aim: This review aims to systematically evaluate the traditional uses, phytochemistry, and pharmacology of the genus Veronicastrum, discuss its medicinal potential, modern scientific research, and the relationship between them, and put forward some suggestions to promote further development and utilization of Veronicastrum. Materials and methods: The traditional uses, phytochemical and pharmacological data related to the genus Veronicastrum from 1955 to date was compiled by surveying the ethnomedicinal books and published papers, and searching the online databases including Google Scholar, China National Knowledge Infrastructure (CNKI), Science Direct, Web of Science and World Flora Online. Results: Species of the genus Veronicastrum are widely used in folkloric medicine and some of their uses have been confirmed in modern pharmacological activities. A total of 89 chemical constituents have been isolated from the genus Veronicastrum, including flavonoids, carbohydrates, iridoids, terpenoids, phytosterols, phenolic acids, and other constituents. Among the compounds isolated, iridoids, flavonoids, and terpenoids are responsible for the biological activities of this genus with significant pharmacological activities both in vitro and in vivo. The extracts and compounds isolated from this genus have been reported to contain a wide range of pharmacological activities such as immunosuppressive, antioxidant, anti-cancer, anti-inflammatory, gastro protective, and antimicrobial activity. Conclusion: The genus Veronicastrum is not only a great herbal remedy, but also has numerous bioactive chemicals with potential for new drug discovery. In the literature, phytochemical investigations have been undertaken on five species. Detailed scientific research is still needed to fully understand this genus. Furthermore, its bioactive chemicals\u27 structure-activity connection, in vivo activity, and mechanism of action ought to be investigated further