Toxicological and anatomical study of vegetative organs of Anthurium maricense Nadruz and Mayo (Araceae)

Among other taxa of Araceae, the genus Anthurium is the largest of the family and one of the most important taxa. Some species of this genus have been used as a condiment, and its plants as ornaments and medicines for over a century. Anthurium maricense is an endemic species from "restingas" of Rio de Janeiro, Brazil, and it is used as ornamental and medicinal plant. This paper aimed an anatomical and toxicological study of its vegetative organs. A. maricense has subterraneous rhizome, adventitious roots and complete leaves. The anatomical features of vegetative organs are similar to other species of Araceae and genus Anthurium, especially the velamen in roots and calcium oxalate crystals in all organs. Under scanning electron microscopy (SEM), longitudinal grooves were observed in the raphides. For toxicological analyses, whole (with crystals) and centrifuged (free from crystals) fractions of the juices of each organ were administered via mouthwash and plantar inoculation to groups of five mices. The formation of edema was observed at 1, 3, 6, 24 and 96 hours and 7, 14, 21 and 28 days. The oral inoculations presented negative results for all groups, without edema. The plantar inoculations showed differing results: with centrifuged juices, mild edema formed but regressed; with whole juices, some animals presented severe edema. Our results indicated distribution and morphology of raphides and diverse chemical substances were related to the edematogenic process. A. maricense may potentially induce more chronic edema if compared to other species of Araceae.