Diterpenoids from Sauropus spatulifolius Leaves with Antimicrobial Activities.

As a plant used in both food and medicine, Sauropus spatulifolius is consumed widely as a natural herbal tea, food source, and Chinese medicine. Inspired by its extensive applications, we conducted a systematic phytochemical study of the leaves of S. spatulifolius . Thirteen new diterpenoids, sauspatulifols A-M ( 1 - 13 ), including four ent -cleistanthane-type diterpenoids ( 1 - 4 ), eight 15,16-di- nor - ent -cleistanthane-type diterpenoids ( 5 - 12 ), and one 17- nor - ent -pimarane-type diterpenoid ( 13 ) as well as one known diterpenoid, cleistanthol ( 14 ), were isolated. All of these diterpenoids feature a 2α,3α-dihydroxy unit within the A ring, and their structures were elucidated by spectroscopic data analysis, electronic circular dichroism calculations, and single-crystal X-ray diffraction analysis. Compound 14 displayed moderate inhibitory activity against Staphylococcus aureus , Staphylococcus epidermidis , Bacillus subtilis , and Shigella flexneri with the same minimum inhibitory concentration value of 12 μg/mL as well as activity against vesicular stomatitis virus and influenza A virus.