Two new alkaloids from Melodinus hemsleyanus Diels.

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Pharmacology

Background:

• Melodinus hemsleyanus Diels is a plant source of bioactive compounds.
• Monoterpenoid indole alkaloids represent a significant class of natural products with diverse biological activities.
• Protein Tyrosine Phosphatase 1B (PTP1B) and Dual Specificity Kinase 2 (Drak2) are implicated in various diseases, making them attractive therapeutic targets.

Purpose of the Study:

• To isolate and characterize new monoterpenoid indole alkaloids from Melodinus hemsleyanus Diels.
• To evaluate the potential inhibitory effects of the isolated compounds on PTP1B and Drak2.

Main Methods:

• Phytochemical investigation of the aerial parts of Melodinus hemsleyanus Diels.
• Structure elucidation of new compounds using 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy and Mass Spectrometry (MS).
• In vitro assays to assess the inhibitory activity against PTP1B and Drak2.

Main Results:

• Two new monoterpenoid indole alkaloids, 14,15-dihydro-14β,15β-epoxy-10-hydroxyscandine (1) and 15α-hydroxy-meloscandonine (2), were identified.
• Twelve known compounds were also isolated from the plant extract.
• Neither of the new compounds exhibited significant inhibitory activity against PTP1B or Drak2.

Conclusions:

• The study successfully identified novel monoterpenoid indole alkaloids from Melodinus hemsleyanus Diels.
• The isolated new compounds did not demonstrate inhibitory effects on the targeted enzymes PTP1B and Drak2.
• Further research may explore other biological activities of these alkaloids or investigate different plant sources for PTP1B/Drak2 inhibitors.