RAI-III and VI, Conformational Isomers of Antitumor Cyclic Hexapeptides, RA-III and VI from Rubia cordifolia

RAI-III and VI, Conformational Isomers of Antitumor Cyclic Hexapeptides, RA-III and VI from <i>Rubia cordifolia</i> New antitumor bicyclic hexapeptides, RA-VI and -VIII from rubia cordifolia ; Conformation-activity relationship II Studies on antitumor cyclic hexapeptides RA obtained from Rubiae Radix, Rubiaceae. VI Minor antitumor constituents. New antitumor bicyclic hexapeptides, RA-XI, -XII, -XIII and -XIV from Rubia cordifolia. Isolation and antitumor activity of cyclic hexapeptides isolated from Rubiae radix. Two antitumour bicyclic hexapeptides from Rubia cordifolia New Cytotoxic Bicyclic Hexapeptides, RA-XXIII and RA-XXIV, from Rubia cordifolia L. Isolation, structural elucidation, and synthesis of RA-XVII, a novel bicyclic hexapeptide from Rubia cordifolia, and the effect of side chain at residue 1 upon the conformation and cytotoxic activity Structures of cytotoxic bicyclic hexapeptides, RA-XIX, -XX, -XXI, and -XXII, from Rubia cordifolia L. RA-dimer A, a novel dimeric antitumor bicyclic hexapeptide from Rubia cordifolia L.