The study of the Typha species has gained attention in tropical areas due to their rapid growth, nutrient release, and contribution to detritus in lakes. Analysis of the degradation of Typha angustifolia has shown that the first stage of decomposition is marked primarily by the release of soluble compounds, indicating that microorganisms have a minor influence at this stage. In subsequent stages, microorganisms act by degrading and consuming phenolic compounds and phosphorus. The remaining compounds form humic substances and are retained in the detritus. Thus, microorganisms significantly degrade organic matter, resulting in a two-fold increase in decomposition. Different forms of phosphorus could be detected in the remaining mass by 31P NMR (nuclear magnetic resonance). By comparing the 31P NMR data between the samples with and without the antibiotic, we can better understand the slow decomposition process of Typha angustifolia.

Astilbin (5,7,3’,4’-tetrahydroxy-2,3-dihydroflavonol-3-ß-o-rhamnoside), a flavonoid with a large range of biological activities, was isolated from Dimorphandra mollis, a shrub common to the Brazilian Cerrado. The purpose of this study is to verify the effects of astilbin on myeloperoxidase (MPO) and horseradish peroxidase (HRP), and its antioxidant activity against hypochlorous acid (HOCl) and total antioxidant activity (TAC) by the 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+). Astilbin inhibited MPO and HRP activities in a concentration-dependent relationship and effectively scavenged HOCl. The TAC by ABTS•+ of astilbin (IC50 ~ 20 mM) was higher than that of uric acid, which was used as a positive control. These data demonstrate that astilbin is a potent antioxidant and that it inhibits MPO and HRP activities efficiently.

Nesta comunicação estamos reportando as propriedades tóxicas dos extratos metanólicos das flores, pedúnculos, folhas, pecíolo e casca do tronco de Dimorphandra mollis sobre as operárias de Apis mellifera. Astilbina (3-beta-O-rhamnosideo de 5,7,3',4'-- tetraidroxi-2,3-diidroflavonol) isolada dos pedúnculos e flores como o seu principal componente, apresentou atividade inseticida sobre abelhas confinadas. Os resultados obtidos indicam que a astilbina reduz a sobrevivência média das abelhas tratadas.

In this communication we have evaluated the toxic properties of methanol extracts from flowers, peduncles, leaves, petioles and stem bark of Dimorphandra mollis to Apis mellifera workers. Astilbin (5,7,3',4'-tetrahydroxy--2,3-dihydroflavonol-3-beta-O-rhamnoside) has been isolated from peduncles and flowers of this plant in large amounts. Astilbin presented insecticidal activity against confined bees. The results suggest that astilbin reduces the average survival of treated bees.