Ternifoliasaponin, a new triterpenoid saponin from the roots of Schumach & Thonn (Rubiaceae).

A new triterpenoid saponin, Ternifoliasaponin (), together with four known compounds () chikusetsusaponin IVa (), chikusetsusaponin IVa methyl ester (), bonushenricoside B ) and Dianoside C () were isolated from roots of Schumach. & Thonn (Rubiaceae). The structures of isolated compounds were elucidated on the basis of spectroscopic analysis and chemical methods. The antibacterial activities of compounds (, and ( were performed by the Muller-Hinton agar diffusion method. The antimicrobial activities of the compounds were studied on (Enterobacteriaceae), and microorganisms. Compound () at 25 mg/mL, showed moderately sensitive effect (8.0 ˂ DIZ ˂14.0 mm) on , and . Compound () at 25 mg/mL and compound () at 12.5 mg/mL exhibited moderately sensitive effect on and Compound () inhibited moderately sensitive the and colonies at 12.5 mg/mL.