Abstract
Teucrium yemense, a medicinal plant commonly grown in Saudi Arabia and Yemen, is traditionally used
to treat infections, kidney diseases, rheumatism, and diabetes. Extraction of the dried aerial parts
of the plant with methanol, followed by further extraction with butanol and chromatography, gave
twenty novel neoclerodanes. Their structures, relative confgurations and some conformations were
determined by MS and 1-D and 2-D NMR techniques. Most were fairly conventional but one contained
an unusual stable orthoester, one had its (C-16)–(C-13)–(C-14)–(C-15) (tetrahydro)furan unit present as
a succinic anhydride and one had a rearranged carbon skeleton resulting from ring-contraction to give
a central octahydroindene bicyclic core, rather than the usual decalin. Mechanisms are proposed for
the biosynthetic formation of the orthoester and for the ring-contraction. Four novel neoclerodanes
increased the glucose-triggered release of insulin from isolated murine pancreatic islets by more than
the standard drug tolbutamide, showing that they are potential leads for the development of new
anti-diabetic drugs.
to treat infections, kidney diseases, rheumatism, and diabetes. Extraction of the dried aerial parts
of the plant with methanol, followed by further extraction with butanol and chromatography, gave
twenty novel neoclerodanes. Their structures, relative confgurations and some conformations were
determined by MS and 1-D and 2-D NMR techniques. Most were fairly conventional but one contained
an unusual stable orthoester, one had its (C-16)–(C-13)–(C-14)–(C-15) (tetrahydro)furan unit present as
a succinic anhydride and one had a rearranged carbon skeleton resulting from ring-contraction to give
a central octahydroindene bicyclic core, rather than the usual decalin. Mechanisms are proposed for
the biosynthetic formation of the orthoester and for the ring-contraction. Four novel neoclerodanes
increased the glucose-triggered release of insulin from isolated murine pancreatic islets by more than
the standard drug tolbutamide, showing that they are potential leads for the development of new
anti-diabetic drugs.
| Original language | English |
|---|---|
| Article number | 8074 |
| Journal | Scientific Reports |
| Volume | 11 |
| DOIs | |
| Publication status | Published - 13 Apr 2021 |
Funding
The authors acknowledge gratefully the Deanship of Scientific Research at King Saud University for funding through the research group project no. RGP-1438-043. We are thankful for support from the BBSRC Institute Strategic Programme Grant on Energy Grasses and Biorefining (BBS/E/W/10963A01) and from the European Regional Development Fund, through the Welsh European Funding Office for the BEACON project. We also thank Helen C. Phillips (Aberystwyth University) for technical support in mass spectrometry and Muhammad Yousuf (King Saud University) for helpful discussions.
