A method of inhibiting the growth of Gram-positive bacteria comprising administering an effective amount of Tellimagrandin II, its pharmaceutically acceptable salt, enantiomer, isomer or tautomer to a subject is provided. The Gram-positive bacteria comprise methicillin-resistant Staphylococcus aureus. A method of treating sepsis comprising administering an effective amount of Tellimagrandin II, its pharmaceutically acceptable salt, enantiomer, isomer or tautomer to a subject is also provided. A method of treating leukemia comprising administering an effective amount of Tellimagrandin II, its pharmaceutically acceptable salt, enantiomer, isomer or tautomer to a subject is further provided.