Antioxidative dolabellanes and dolastanes from brown seaweed Padina tetrastromatica as dual inhibitors of starch digestive enzymes

Abstract

New dolabellanes {6-methoxy-dolabella-8(17),12-diene-10β,18-diol (1), 3-methoxy-dolabella-12(18)-ene-4β-ol (2), 3-methoxy-dolabella-10,18(19)-diene-5α,8β-diol (3)} and dolastanes {2,7-dimethoxy-14α-hydroxy-dolasta-1(15),9-diene (4) and 4,7-dimethoxy-9β,14α-dihydroxy-dolasta-1-ene (5)} were identified from brown seaweed Padina tetrastromatica (family Dictyotaceae), collected from the southeast coast of India. Compounds 1–3 were found to possess dolabellane skeleton with [9.3.0] cyclotetradecane framework whereas, 4–5 were composed of tricyclic diterpenes with linear arrangement of six-seven-five fused alicyclic rings. Compounds 3 and 5 registered greater antioxidative activities (IC₅₀ ≤0.63 mg/mL) than other analogues (IC₅₀ ≥0.65 mg/mL), whereas their attenuating potentials against carbolytics α-amylase and α-glucosidase (IC₅₀ ∼0.12–0.14 mg/mL) were comparable with those displayed by acarbose (IC₅₀ 0.14-0.12 mg/mL). Bioactive potentials of titled compounds were assessed by electronic and lipophilic parameters. The lesser binding energies of 3 (−9.71 kcal/mol) and 5 (−8.59 kcal/mol) through molecular docking demonstrated their effective hydrogen bonding interactions with α-amylase. Thus, dolabellanes and dolastanes might be used as anti-diabetic and antioxidant leads to reduce the risk of hyperglycaemia.

Graphical Abstract

Keywords:

• Padina tetrastromatica
• Dictyotaceae
• dolabellanes
• dolastanes
• antioxidative activity
• hyperglycaemia
• molecular docking

Acknowledgements

The authors thank the Director, Indian Council of Agricultural Research-Central Marine Fisheries Research Institute (ICAR-CMFRI), and Head, Marine Biotechnology Division, ICAR-CMFRI for guidance and support.

Conflict of interest

The authors declare no competing financial interest.

Additional information

Funding

The work was funded by Science and Engineering Research Board of the Department of Science and Technology, New Delhi, India (grant number SR/S1/OC-96A/2012).