Sentence:  Around 1970, Japan approved <WSD>stevia</WSD> as a sweetener and flavor enhancer, and, in the last 35 years of Japanese employment, not a single case of toxic or deleterious effect has been brought to light. 
Meaning of the word marked with <WSD> tags:  A sweetener, many times sweeter than an equal amount of sugar, extracted from (ver=161102), that can be substituted for sugar for some purposes.