Diones A. Dias

Sesquiterpene lactones and other constituents from Eremanthus seidelii, E. Goyazensis and Vanillosmopsis erythropappa

Abstract Extraction of the aerial parts of Eremanthus seidelii and reinvestigation of E. goyazensis gave four new 4,5-dihydrofuranoheliangolides and two new 4,5-dihydroeremantholides as well as some known sesquiterpene lactones. X-Ray analysis of one of the 4,5-dihydroeremantholides showed that the new lactones from E. seidelii and E. goyazensis differ in C-4 stereochemistry from isomers previously isolated from Eremanthus and related species. Criteria based on NMR spectroscopy for distinguishing between the two series are given. The C-4 stereochemistry of zexbrevin is discussed and the tentative conclusion is reached that in the earlier correlation between tagitinin A and zexbrevin C-4 epimerization took place at the oxidation stage. Reinvestigation of Vanillosmopsis erythropappa wood resulted in isolation of several lactones not previously reported from this species.

Evaluation of the antimicrobial activity of crude extracts and isolated constituents from Chresta scapigera

Crude extracts and eight isolated compounds from Chresta scapigera were evaluated for antibacterial and antifungal activities by the agar-well diffusion method. Twenty strains, including Gram-positive and Gram-negative bacteria and yeasts were used in the bioassay. Hexane extracts presented the best results while ethanol extracts did not indicate inhibition of the microbial growth. Amongst the evaluated compounds b-amyrin acetate, tiliroside and luteolin showed the strongest antimicrobial effect.

Bioactivity of crude extracts and some constituents of Blutaparon portulacoides (Amaranthaceae).

Crude extracts (aerial parts and roots, both dried), methylenedioxyflavonol, and a mixture of acyl steryl glycosides isolated from Blutaparon portulacoides, were assayed for their toxicity against Trypanosoma cruzi trypomastigotes and Leishmania amazonensis amastigotes from axenic cultures. The antimicrobial activity was also investigated, in a screening conducted using fifteen strains of Gram-positive and Gram-negative bacteria, along with the yeasts, Candida albicans and Candida tropicalis. To assess the antibacterial activity of the isolated compounds, the minimum inhibitory concentrations (MICs) were determined. There are no reports of acyl steryl glycosides in the genus Blutaparon and their biological activities are being evaluated for the first time.

Sesquiterpene lactones from Brazilian Tithonia diversifolia

Abstract Aerial parts of Tithonia diversifolia collected in Sao Paulo State afforded two new heliangolides in addition to the heliangolides tagitinin F and 1,2-epoxytagitinin C, one known guaianolide and the flavone hispidulin. Structures were established by spectroscopic studies.

Isolation and HPLC quantitative analysis of antioxidant flavonoids from Alternanthera tenella Colla.

Abstract Phytochemical analysis of the antioxidant ethanolic extract of Alternanthera tenella Colla led to the isolation of six flavonoids, acacetin 8-C-[α-ʟ-rhamnopyranosyl-(1→2)-β-ᴅ-glucopyranoside] (1), 2″-O-α-ʟ-rhamnopyranosyl-vitexin (2), 2″-O-β-d-glucopyranosyl-vitexin (3), vitexin (4), quercetin (5) and kaempferol (6). All the structures were established by ESIMS and NMR spectroscopic methods. Antioxidant capacity of extract, fractions and isolated compounds was determined using the oxygen radical absorbance capacity (ORAC) assay and extract, fractions and flavonoids isolated showed antioxidant activity in vitro. Moreover, the total soluble phenolic contents of the extract and fractions were measured using the Folin- Ciocalteau reagent and the quantitative analysis of flavone C-glycosides major constituents was performed by HPLC

Evaluation of immunomodulatory and anti-inflammatory effects and phytochemical screening of Alternanthera tenella Colla (Amaranthaceae) aqueous extracts

Alternanthera tenella Colla extracts are used in Brazilian traditional folk medicine to treat a variety of infectious diseases as well as inflammation and fever. In this work, the immunomodulatory, anti-inflammatory and potential toxic effects of cold (CAE) and hot (HAE) aqueous extracts of A. tenella were investigated in vivo. In addition, we analyzed the phytochemical properties of both extracts. BALB/c mice were immunized in vivo with sheep red blood cells and concomitantly inoculated intraperitoneally (i.p.) with each extract (50, 100 or 200 mg/kg). Specific antibody-producing cells were enumerated using plaque-forming cell assays (PFC) and anti-SRBC IgG and IgM serum levels were measured via enzyme-linked immunosorbent assay. Body and lymphoid organ weights were determined after treatments in order to evaluate toxic effects. Carrageenan-induced paw edema was employed to investigate anti-inflammatory activity in mice inoculated i.p. with CAE or HAE (200 or 400 mg/kg). Phytochemical screening was performed using spectrometric and chromatographic approaches and revealed that CAE possessed higher tannin and flavonoid levels than HAE. PFC numbers were increased after treatment with CAE (100 mg/kg) four days after immunization, as were the serum antibody titers after four and seven days, suggesting immunostimulatory activity through modulation of B lymphocyte functions. Body and organ weights did not show major changes, suggesting that extracts administered to mice did not induce significant toxicity. Both extracts had significant anti-inflammatory activity in the paw edema assay. These results suggested that aqueous extracts from A. tenella contained several chemical compounds that possess positive and/or negative modulator effects on the immune system, which appeared to correlate with tannin and flavonoid levels in those extracts. In summary, these studies provide important insight into the biological activities of A. tenella.

Trypanocidal and antimicrobial activities of Moquinia kingii

A chloroform crude extract (aerial part) and two compounds, apigenin (1) and cynaropicrin (2), isolated from Moquinia kingii were evaluated against Trypanosoma cruzi trypomastigotes in vitro. Antimicrobial activity was also screened using twenty-two strains including gram-positive and gram-negative bacteria and the yeasts Candida albicans and C. tropicalis. The chloroform crude extract, fractions and isolated compounds from M. kingii were active for both activities. The IC50 values for trypanocidal activity obtained for cynaropicrin and apigenin were 93.5 microg/ml and 181 microg/ml, respectively, while the minimum inhibitory concentrations (MICs) varied from 100 microg/ml to 2500 microg/ml, against the strains of bacteria and yeasts evaluated.

A New Heptasubstituted (E)-Aurone Glucoside and Other Aromatic Compounds of Gomphrena agrestis with Biological Activity

Abstract A new aurone 1 and two known substances, aurantiamide acetate (2) and tiliroside (3), were isolated from the ethanolic extract of Gomphrena agrestis. The structural determination of 1 was based on spectroscopic and spectrometric data. The substance was defined as (E)-3′- O-β-ᴅ-glucopyranosyl-4,5,6,4′-tetrahydroxy-7,2′-dimethoxyaurone. Biological activity of the ethanolic crude extract and isolated compounds against bacteria, fungi and Leishmania amazonensis amastigotes was evaluated. This appears to be the first report documenting aurone and aurantiamide compounds in the Amaranthaceae family. In the evaluation of biological activity the ethanolic extract of G. agrestis and compounds 1, 2, and 3 were shown to be active mainly against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa.

Analysis of Medicinal Plants and Crude Extracts by Synchrotron Radiation Total Reflection X-Ray Fluorescence

Abstract Plants and aqueous extracts of Alternanthera maritima (aerial parts and roots), Alternanthera brasiliana and Alternanthera tenella colla (total plant) were selected for analysis of metals bioaccumulation. The synchrotron radiation total reflection X-ray fluorescence (SRTXRF) was used for excitation of the samples and a Si(Li) detector for the detection of the characteristic X-rays emitted by the sample elements. The elements P, S, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, and Sr were detected in all samples. Further-more Al, Si, Cl, Ni, Br, Rb, Cd, Sn, Sb, Hg, and Pb in Alternanthera maritima samples; Si, Co, Cd, Sn, Sb, and Ce in Alternanthera brasiliana and Al, Si, Co, Ni, Br, Cd, Sn, Sb, and Ce in Alternanthera tenella colla were found. The concentration obtained in the samples for K-shell lines varied from 1.63 µg g−1 for Ni to 3.34 × 105 µg g−1for K, and for L-shell the values ranged from 1.64 x 101 µg g−1 for Cd to 6.71 × 102 µg g−1 for Sn.

Flavonoids and heliangolides from Lychnophora diamantinana

Abstract In addition to known compounds, investigation of the aerial parts of Lychnophora diamantinana afforded two new sesquiterpene lactones of the heliangolide type. Along with a flavanone and a flavonol, the first dihydroflavonol was isolated from the tribe Vernonieae.