tivc pharmacological action leading to the stimulation of 

 diuresis was not demonstrated. 



V. As an antimalarial, various preparations (decoction, tinc- 

 ture, and fhiid extract) of the roots administered orally 

 showed negatixe results, except in one case. 



\i. Toxic effects in humans included nausea, vomiting and 

 diarrhea, at a daily dose of 200 g of a 10% decoction, in 



more sensitive indi\iduals. 



3. I'hytochemical basis of ethnomedical uses 



The diverse folk medicinal uses o{ Stevia species perhaps stem 

 from the bitter taste of its members (Soejarto et al., 1983), a 

 property often associated with medicinal virtues. This bitter 

 taste is probably due to the presence of sesquiterpene lactones 

 (Rodriguez ct al.. 1976; Rodriguez, 1977) or to certain diter- 

 penes (Cocker, 1966; Sticher. 1977). Sesquiterpenes appear to be 

 characteristic in plants oi the Compositae (Hcgnauer, 1977; 

 Herz, 1977), and ha\e been isolated previously from several spe- 

 cies o^ Sicvia (Rios et a!., 1967; Salmon et al., 1973; Rodriguez 

 ct al., 1976; Salmon et al, 1977; Bohlmann et al., 1979, 1982). 

 The extent to which these principles are responsible for alleged 

 therapeutic activities in members of Stcvia remains to be 

 in\estigated. 



Many species oi Stcvia exhibit a pungent to pleasantly aro- 

 matic odor, which in certain species has been referred to by 

 Grashoff (1972) as a goat's smell. Strong and aromatic odors 

 from plants are due to the presence of essential oils, which pos- 

 sess rubefacient, irritant and antimicrobial properties (Harvey, 

 1975). Montes (1969) and Fujita et al. (1977) have demonstrated 

 the presence of volatile constituents in Sievia saiureifolia and S. 

 Rchaudiana, respectively. This attribute may be responsible for 

 certain alleged therapeutic uses, such as antipyretics, anti- 

 rheumatics, diaphoretics, and to treat burns, scratches, and skin 

 diseases. 



For other therapeutic activities, for which species of Stcvia 

 have been allegedly used, as antidiarrheals, uterine relaxants 

 (antids smenorrheics), in the prevention of hair from falling, and 

 in cardiac treatments, to mention only a few, the phytochemical 

 basis is not known at present. 



20 



