Dolabranes from the Chinese Mangrove, Ceriops tagal

Area of Science:

• Natural Product Chemistry
• Phytochemistry
• Marine Natural Products

Background:

• Mangrove plants, such as Ceriops tagal, are a rich source of diverse chemical compounds.
• Dolabranes are a class of diterpenoids with various reported biological activities.
• Previous research has explored the chemical constituents of Ceriops species, but specific dolabrane subclasses remain underexplored.

Purpose of the Study:

• To isolate and characterize new dolabrane compounds from the Chinese mangrove Ceriops tagal.
• To investigate the potential biological activities of the isolated compounds, including antifeedant and anticancer properties.
• To report the first isolation of 16-nordolabranes and 15,16-dinordolabranes from the Ceriops genus.

Main Methods:

• Extraction and isolation of compounds from Ceriops tagal stems and twigs.
• Structure elucidation using comprehensive spectroscopic data (NMR, MS, etc.).
• Comparison of spectral data with existing literature for known compounds.
• Single-crystal X-ray diffraction analysis for determining relative configurations of specific compounds.
• Bioassays to evaluate antifeedant activity against insect larvae and cytotoxicity against human cancer cell lines.

Main Results:

• Six new dolabranes, designated tagalsins P-U (1-6), were successfully isolated.
• Seven known dolabranes, an abietane, and a pimarane were also identified.
• The structures and relative configurations of tagalsins P and Q (1, 2) were confirmed via X-ray diffraction.
• Tagalsins Q (2), R (3), and U (6) exhibited moderate antifeedant activity against Brontispa longissima larvae.
• No significant anticancer activity was observed for the newly isolated dolabranes against tested human cancer cell lines.

Conclusions:

• This study reports the first isolation of 16-nordolabranes and 15,16-dinordolabranes from plants belonging to the Ceriops genus.
• The identified dolabranes from Ceriops tagal represent a novel chemical diversity within this mangrove species.
• The moderate antifeedant activity suggests potential applications in pest control, while the lack of cytotoxicity warrants further investigation into other biological activities.