Tubeimoside I, a new cyclic bisdesmoside from chinese cucurbitaceous folk medicine "Tu Bei Mu", a tuber of Bolbostemma paniculatum - Kasai, Ryoji; Miyakoshi, Masazumi; Matsumoto, Kazuhiro; Nie, Rui-Lin; Zhou, Jun; Morita, Toshinobu; Tanaka, Osamu (Chemical & pharmaceutical bulletin, 1986)