João Máximo de Siqueira

Atividade antioxidante e captora de radicais livres dos extratos de Achyrocline alata (Kunth.) DC. em comparação com extratos de Achyrocline satureioides (Lam. ) DC

Achyrocline alata (Kunth.) DC. and Achyrocline satureioides (Lam.) DC. are species belonging to the family Asteraceae widely used in the folk medicine of Campo Grande, Mato Grosso do Sul, being considered substitute plants. The present work aimed to compare the obtained extracts of these species to simple chemical assays, in order to test the antioxidant activity and free radical scavenging, using β-carotene and DPPH as reference, respectively. With these assays it was observed that the obtained extracts of Achyrocline satureioides were more active, as free radical scavenging, than the same obtained extracts of Achyrocline alata. These chemical assays were compared to a known patterned, quercetin, and and they were dealt under triplicate basis.

An azafluorenone alkaloid and a megastigmane from Unonopsis lindmanii (Annonaceae)

The azafluorenone alkaloid 5,8-dimethoxy-7-hydroxy-1-methyl-4-azafluoren-9-one and the megastigman (–)-(5R*, 6S*)-megastigman-3-one-10,7-olide were isolated from aerial parts of Unonopsis lindmanii (Annonaceae), along with the known compounds (3S*, 5S*, 8R*)-3,5-dihydroxymegastigma-6,7-dien-9-one (grasshopper ketone), N-trans-feruloyltyramine, (–)-anonaine, (–)-asimilobine, liriodenine and (–)-syringaresinol. This is the first description of the presence of megastigmanes in Annonaceae. The structures of the compounds were elucidated based on spectroscopic data.

Anti-inflammatory effects of the butanolic fraction of Byrsonima verbascifolia leaves: Mechanisms involving inhibition of tumor necrosis factor alpha, prostaglandin E2 production and migration of polymorphonuclear leucocyte in vivo experimentation

The leaves of Byrsonima verbascifolia (Malpighiaceae) are traditionally used to treat various diseases including inflammatory conditions. The main goal of this study was to evaluate the in vivo anti-inflammatory activity of the polar constituents from the butanolic fraction of B. verbascifolia leaves (BvBF), as well as to investigate the mechanisms involved in the anti-inflammatory activity. The polar constituents were identified by liquid chromatography coupled to diode array detector and mass spectrometry (LC-DAD–MS) and matrix-assisted laser desorption/ionization – time-of-flight mass spectrometry (MALDI-TOF MS) to obtain a complete chemical profile of the fraction. Forty-five compounds were detected in the BvBF by LC-DAD–MS/MS, including condensed tannins, phenolic acids, flavonoids (flavones and flavonols) and other compounds. In addition, several condensed tannins were identified by MALDI-MS/MS, which are composed predominantly by procyanidin units (PCY) and up to six flavan-3-ol units. The BvBF exhibited significant antioxidant and anti-inflammatory activities. The BvBF inhibited paw edema and polymorphonuclear (PMN) leukocyte migration to the footpad and pleural cavity induced by carrageenan. Furthermore, a minor dose (12.50 mg/kg) of BvBF effectively decreased tumor necrosis factor alpha (TNF-α) and prostaglandin E2 (PGE2) levels in the footpad. These findings suggest that the mechanism of the anti-inflammatory action in the BvBF is linked to the inhibition of the production of inflammatory mediators such as TNF-α and PGE2 and the PMN cell migration.

CONSTITUINTES QUÍMICOS E ATIVIDADE FITOTÓXICA DAS FOLHAS DE Annona nutans

The phytochemical investigation and evaluation of the phytotoxic effect of the extract and fractions obtained from the leaves of Annona nutans(R. E. Fr.) R. E. Fr. were performed. Phytotoxic activity was assessed on radicle and hypocotyl of Allium cepa and Lactuca sativa, where chloroform and ethyl acetate fractions proved active. Phytochemical investigation of the chloroform fraction was allowed identification of polyketides derivatives: triacontanal, 16-hentriacontane, octacosanol and triacontanol, using the 1H NMR technique associated with data from GC/MS. Using ethyl acetate fraction, with low activity, flavonoids 3-O-β-D-galactopyranosyl-isorhamnetin, 3-O-β-D-galactopyranosyl-quercetin and 3-O-β-D-apiofuranosyl-(1→2)-galactopyranosyl-quercetin were identified, determined by spectrometric techniques one and two-dimensional NMR, combined with mass spectral data. All substances are being reported for the first time in Annona nutans. The phytotoxic activity of chloroform fraction may be related to the presence of triacontanol and similar substances. Triacontanol stimulates growth at very low concentrations, but can have an inhibitory effect at higher concentrations, such as those reported for auxin analogs. The toxicity assay using Artemia salina (BST) was also performed, with the chloroform fraction showing a negligible lethal dose, LD50 = 500 mg mL-1, while the other fractions and extracts showed no activity. Thus, the presence of acetogenins was ruled out.

Chemical characterization and bioherbicidal potential of the essential oil from the leaves of Unonopsis guatterioides (A.DC.) R.E.Fr. (Annonaceae)

Abstract The chemical composition and the phytotoxicity potential of the essential oil from leaves of Unonopsis guatterioides (A.DC.) R.E.Fr. (Annonaceae) was investigated. Gas chromatography/mass spectrometry analyses revealed 16 constituents representing 99.50% of the total essential oil, composed mainly of sesquiterpenes. α-copaene, bicyclogermacrene and trans-caryophyllene were the major components (15.7% each), followed by α-humullene, allo-aromadendrene and (+)-spathulenol (9.0, 8.4 and 7.3%, respectively). The essential oil inhibited seed germination and growth in both monocotyledon (Allium cepa) and dicotyledon (Lactuca sativa) models, pointing to a promising application of this oil obtained from the leaves of U. guatterioides as a new bioherbicide.