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

Abstract

Two new dihydroisocoumarins (scorzolongin I (1), and scorzolongin II (2)) and nine known compounds (3′,5′-dimethoxy hydrangenol (scorzolongin III, 3), cladantholide (4), dammar-24-ene-3β-ol (5), taraxasterol (6), β-sitosterol (7), mangifgerursanone (8), and a mixture of α-amyrenone (9a), β-amyrenone (9b), and dammar-24-ene-3-one (9c) in about 1:1:2 ratio) were identified from the dichloromethane fraction of Scorzonera longiana. The structure of all compounds (1–9a–c) were elucidated by extensive 1D and 2D NMR (¹H, ¹³C/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 S. longiana for the first time. An antimicrobial assay against eight microorganisms was applied to isolated compounds 1–3. Scorzolongin I, and scorzolongin II, and scorzolongin III showed notable activity against gram (-) (Escherichia coli and Yersinia pseudotuberculosis) and fungi (Candida albicans, Saccharomyces cerevisiae) with 20 mm inhibition zone each. Scorzolongin II (2) exhibited strong activity against E. coli, Y. pseudotuberculosis, Mycobacterium smegmatis C. albicans, S. cerevisiae with MIC value of 33.8 μg/mL.

Graphical Abstract

Keywords:

• Scorzonera longiana
• dihydroisocoumarins
• sesquiterpene
• triterpenes

Acknowledgement

The authors are thankful to Karadeniz Technical University for the financial support (KTÜ-BAP-TSA-2020-8961). We also thank to Dr. Şengül Alpay Karaoğlu for the help with the antimicrobial activity test.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are thankful to Karadeniz Technical University for the financial support (KTÜ-BAP-TSA-2020-8961). We also thank to Dr. Şengül Alpay Karaoğlu for the help with the antimicrobial activity test.