Tumor Inhibitors. XXIII.1 The Cytotoxic Principles of

CYIWWXIC~ ' I Z I S C I P L EOF ~ Xarah wegunus H.

Bluy 1967

387

Tunior Inhibitors. XXIII.' The Cytotoxic Principles of Murah oregunus H.'

alcoholic extract of the root of .Ilumh oi'eyanucs H. wab foiiiid to show bigiiificitiit iiihibitory activity agaiiist carcinoma of the iiawpharyiix carried in cell ciiltiire (KB). Systematic fractioiiatioii of thi- extract has led to the imlatioii aiid characterization of the cytotoxic tetracyclic triterpeiies, iaocucurbitaciii B, ciiciirbitaciii B, dih?droc~icurbitaciiiB, aiid cucurbitaciii E. h i i

liiiriinii

I n the course of a continuing search for tumor inhibitors of plant origin, an alcoholic extract of the roots of J f a i u h oregunus Howell was found to show significant inhibitory activity against human carcinoma of the nasopharynx carried in cell culture (I