What is of, pertaining to, or obtained from, Polygala; specifically, designating an acrid glucoside (called polygalic acid, senegin, etc.), resembling, or possibly identical with, saponin called?

polygalic — Of, pertaining to, or obtained from, Polygala; specifically, designating an acrid glucoside (called polygalic acid, senegin, etc.), resembling, or possibly identical with, saponin. (Webster's 1913.)

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