Outline of the classification of flowering plants (Magnoliophyta)

Phloroglucinol compounds of natural origin

A new drug screening method was devised utilizing Trypanosoma cruzi cells that express the Escherichia coli beta-galactosidase gene. Transfected parasites catalyze a colorimetric reaction with chlorophenol red beta-D-galactopyranoside as substrate. Parasite growth in the presence of drugs in microtiter plates was quantitated with an enzyme-linked immunosorbent assay reader. The assay was performed with the mammalian form of T. cruzi that requires intracellular growth on a monolayer of fibroblast cells. To determine if selective toxicity to the parasites was occurring, the viability of the host cells in the drug was assayed with AlamarBlue. The drugs benznidazole, fluconazole, and amphotericin B were shown to inhibit the parasites at concentrations similar to those previously reported. Several compounds were tested that are inhibitors of glyceraldehyde-3-phosphate dehydrogenase of the related organisms Leishmania mexicana and Trypanosoma brucei. One of these compounds, 2-guanidino-benzimidazole, had an 50% inhibitory concentration of 10 microM in our assay. Two derivatives of this compound were identified with in vitro activity at even lower concentrations. In addition, the assay was modified for testing compounds for lytic activity against the bloodstream form of the parasite under conditions used for storing blood products. Thus, an assay with beta-galactosidase-expressing T. cruzi greatly simplifies screening drugs for selective anti-T. cruzi activity, and three promising new compounds have been identified.

Efficient technique for screening drugs for activity against Trypanosoma cruzi using parasites expressing beta-galactosidase.

https://www.repositorio.ufop.br/bitstream/123456789/805/6/ARTIGO_TrioxygenatedNaturallyOccurring.pdf

Tetraoxygenated naturally occurring xanthones

Our attempt at putatively phylogenetic classifications of Angiospermae, considering our vast ignorance of more than 120 million years of evolution of the class, must be very tentative and elastic to make full use of the new approaches and new data constantly being made available to us. Some of the realignments thus required in my system of classification are here explained. Among others, the Paeoniales are recognized and include Glaucidiaceae; various shifts of families are made within Thei–florae–Violiflorae–Malviflorae; Thymelaeaceae and Simmondsiaceae are transferred to Euphorbiales; Emblingiaceae, Gyrostemonaceae and Bataceae are added to Sapindineae; Fabineae, with Connaraceae, Surianaceae and Fabaceae, are transferred to Rutiflorae; Proteiflorae are placed near Rutiflorae, especially Fabineae; the largely Australasian–African Pittosporales are explained; Cornaceae are severely pruned; Haemodoraceae and Velloziaceae are transferred to Commelinales; Arecales, Cyclanthales and Pandanales are separated into unrelated superorders; and Typhiflorae are moved into closer proximity with Commeliniflorae.

Proposed new realignments in the angiosperms

Xanthonolignoids from Kielmeyera and Caraipa species—13C NMR spectroscopy of xanthones

Transmission of Chagas disease by blood transfusion is a major health problem in Central and South America. The annual incidence of transfusion-transmitted Chagas disease in Brazil is about 20 000 cases. Crystal violet is the only trypanosomicidal agent available at present, but there are some restrictions on its use. In a search for possible new chemoprophylactic agents, several natural products of different structural types were tested in vitro against infective blood trypomastigptes of Trypanosoma cruzi . Four compounds had high activity at a concentration of 5 × 10 −4 m : the diarylpropanoids (3R)-claussequinone, (R)-4-methoxydalbergione and (S)-4,4′-dimethpxydalbergione, and 15-deoxygoyazensolide, a sesquiterpenelactone. Haemoculture and serology of mice inoculated with infected blood treated with these active compounds were negative after 3 and 6 months. The benzpquinpne moiety seemed to be important for this activity since lapachol and related naphthoquinones are known to be trypanosomicidal. 15-Deoxygoyazensolide has previously been recognized as a schistosomicide.

Screening in vitro of natural products against blood forms of Trypanosoma cruzi

/pdf/estrutura-quimica-e-atividade-biologica-de-naftoquinonas-de-roa4halxpa.pdf

Antonio A.L. Mesquita

Papers

Xanthonolignoids from Kielmeyera and Caraipa species—13C NMR spectroscopy of xanthones

Screening in vitro of natural products against blood forms of Trypanosoma cruzi

Estrutura Química e Atividade Biológica de Naftoquinonas de Bignoniáceas Brasileiras

Flavonoids from four compositae species

Anthraquinones from Vismia species