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15,21-Cyclowithanolides from Jaborosa bergii
Viviana E Nicotra1, Roberto R Gil, Clarisa Vaccarini
1Departamento de Química Orgánica and IMBIV, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
Journal of Natural Products
|December 3, 2003
Summary
Six new withanolides were discovered in Jaborosa bergii, with five featuring a novel norbornane-type steroid structure. Compound 1 demonstrated selective phytotoxicity, impacting both monocot and dicot plant species.
Area of Science:
- Natural Product Chemistry
- Phytochemistry
- Organic Chemistry
Background:
- Jaborosa bergii is a plant source of bioactive natural products.
- Withanolides are a class of steroidal lactones with diverse biological activities.
- Previous isolation of 2,3-dehydrojaborosalactol M (7) from J. bergii.
Purpose of the Study:
- To isolate and characterize new withanolides from Jaborosa bergii.
- To elucidate the novel chemical structures of these compounds.
- To evaluate the phytotoxic potential of the isolated compounds.
Main Methods:
- Extraction of aerial parts of Jaborosa bergii.
- Spectroscopic characterization including 1D and 2D NMR and Mass Spectrometry (MS).
- Phytotoxicity assays on monocotyledonous and dicotyledonous species.
Main Results:
- Isolation and characterization of six new withanolides (1-6).
- Five compounds (1-5) possess a novel norbornane-type structure in ring D of the steroid nucleus.
- Compound 1 exhibited selective phytotoxicity against both monocot and dicot species.
- Compound 6 is a 5alpha-chloro-6beta-hydroxy analogue of a known withanolide.
Conclusions:
- Jaborosa bergii is a rich source of structurally unique withanolides.
- The novel norbornane-type steroid nucleus represents a new structural motif in withanolide chemistry.
- Compound 1 shows potential as a selective phytotoxic agent, warranting further investigation.