A new naphthoquinone from Ceiba pentandra

Area of Science:

• Natural Product Chemistry
• Organic Chemistry
• Phytochemistry

Background:

• Ceiba pentandra (Kapok tree) is a tropical tree known for its diverse phytochemical constituents.
• Naphthoquinones are a class of organic compounds with a wide range of biological activities.
• Isolation and structural elucidation of novel natural products are crucial for discovering new bioactive compounds.

Purpose of the Study:

• To isolate and characterize chemical constituents from the heartwood of Ceiba pentandra.
• To identify and elucidate the structure of a new naphthoquinone derivative.
• To confirm the structure of a known naphthoquinone isolated concurrently.

Main Methods:

• Extraction of compounds from Ceiba pentandra heartwood.
• Chromatographic separation techniques for isolating individual compounds.
• Extensive 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy for structural determination.

Main Results:

• Isolation of a new naphthoquinone, 2,7-dihydroxy-8-formyl-5-isopropyl-3-methyl-1,4-naphthoquinone (1).
• Isolation of a known naphthoquinone, 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthoquinone (2).
• Complete structural elucidation of compounds 1 and 2 using comprehensive NMR data.

Conclusions:

• The heartwood of Ceiba pentandra is a source of structurally diverse naphthoquinones.
• The identification of compound 1 expands the known naphthoquinone chemical space.
• Advanced NMR techniques are essential for the unambiguous characterization of complex natural products.