Avaliação da correlação de íons metálicos e compostos fenólicos em plantas medicinais

Abstract

The use of medicinal plants has become an alternative therapy of great acceptance by the population and the medical community. Physicians prescribe medicinal plants and phytotherapics whose biological activities, effectiveness and safety have been scientifically investigated and proved (CECHINEL & YUNES,1998; KINGHORN,2001). Plants are also resources of active principles used as models in the synthesis of modified compounds with improved activity and lesser toxic effects. This research aimed to determine by flame atomic absorption spectrometry the concentration of essential and no essential metals in aqueous infusions, in roasted plant samples and in 70% and 95% v/v ethanolic extracts. The quantity of total phenols and flavonoids in the aqueous infusions and in the ethanolic extracts were further determined through UV-vis spectrometry at 760 and 425 nm, respectively. Additionally, the antimicrobial activity of the ethanolic extracts and aqueous infusions was assayed by the diffusion technique in agar. The appraised plants were the marigold (Calendula officinalis L.), the grass lemon (Cymbopogon citratus (DC) Stapf) and the "espinheira-santa" (Maytenus ilicifolia Mart. ex. Reissek) cultivated and marketed in Guarapuava - PR region. The obtained results showed that metals extraction in the infusions varied among 6,2 to 68,2% of the total amount found in each plant; the poisonous metals were just found in the roasted samples. The 70% ethanolic extract of grass lemon presented the largest amount of total phenols and flavonoids. The 70% and 95% espinheira santa and grass lemon extracts and 95% marigold extracts showed important antimicrobial activity against Klebsiella sp.