Recognizing the Toxicodendrons (poison ivy, poison oak, and poison sumac).
Poison ivy, poison oak, and poison sumac are now classified in the genus Toxicodendron which is readily distinguished from Rhus. In the United States, there are two species of poison oak, Toxicodendron diversilobum (western poison oak) and Toxicodendron toxicarium (eastern poison oak). There are also two species of poison ivy, Toxicodendron rydbergii, a nonclimbing subshrub, and Toxicodendron radicans, which may be either a shrub or a climbing vine. There are nine subspecies of T. radicans, six of which are found in the United States. One species of poison sumac, Toxicodendron vernix, occurs in the United States. Distinguishing features of these plants and characteristics that separate Toxicodendron from Rhus are outlined in the text and illustrated in color plates.
Toxicodendron radicans dermatitis with black lacquer deposit on the skin.
Four patients with clinical Toxicodendron dermatitis (poison ivy) presented with dramatic black lacquer-like deposits on several lesions. This black deposit was also observed at sites of injury on poison ivy plants and was reproduced on volunteers by the application of plant sap on the skin. Histologically, the observed material was identified in the stratum corneum. This little-recognized phenomenon has been mentioned in past dermatologic literature.
Antitumor agents from Agave schottii (Amaryllidaceae).
Extracts of Agave schottii Engelm. (Amaryllidaceae) were shown to be effective inhibitors of the Walker carcinoma 256 (intramuscular) tumor system of the CCNSC. The active material was shown to be saponin. By means of a Silica Gel G dry-column technique, an effective separation of the acetates of the saponins present was accomplished. Gitogenin was identified as the genin of all saponins present. While the sugar associated with the saponin showing the highest degree of activity was galactose, the sugars associated with the three other saponins were identified as a mixture of galactose and glucose.