Two new dihydroisocoumarins and terpenoids from Scorzonera longiana Sümbül an endemic species to Turkey and their antimicrobial activity.

Two new dihydroisocoumarins (scorzolongin I (), and scorzolongin II ()) and nine known compounds (3',5'-dimethoxy hydrangenol (scorzolongin III, ), cladantholide (), dammar-24-ene-3-ol (), taraxasterol (), -sitosterol (), mangifgerursanone (), and a mixture of α-amyrenone (), β-amyrenone (), and dammar-24-ene-3-one () in about 1:1:2 ratio) were identified from the dichloromethane fraction of . The structure of all compounds ( were elucidated by extensive 1D and 2D NMR (H, C/APT, COSY, HMBC, HSQC, and NOESY) spectroscopy, UV, FT-IR, and LC-QTOF-MS data and by comparison of their NMR data with the literature. These compounds have been isolated from for the first time. An antimicrobial assay against eight microorganisms was applied to isolated compounds -. Scorzolongin I, and scorzolongin II, and scorzolongin III showed notable activity against gram (-) ( and ) and fungi ) with 20 mm inhibition zone each. Scorzolongin II ( exhibited strong activity against , with MIC value of 33.8 μg/mL.