Structurally diverse limonoids and bio-active evaluation from Trichilia connaroides

Area of Science:

• Natural Product Chemistry
• Medicinal Chemistry
• Organic Chemistry

Background:

• Trichilia connaroides is a plant source of bioactive compounds.
• Limonoids are a class of terpenoids with diverse biological activities.
• Structural elucidation of complex natural products is crucial for understanding their function.

Purpose of the Study:

• To isolate and characterize new limonoids from Trichilia connaroides.
• To evaluate the cytotoxic and anti-inflammatory potential of isolated compounds.
• To investigate rare structural motifs in natural product chemistry.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure determination via spectroscopic analyses (NMR, MS) and X-ray diffraction.
• Computational analysis using TD-DFT-ECD calculations for absolute configuration.
• In vitro assays for cytotoxicity and anti-inflammatory activity.

Main Results:

• Four new limonoids (trichiconlide G, 2-hydroxyltrijugin F, 23-oxo-21-hydroxyltrijugin F, 21-oxo-23-hydroxyltrijugin F) and sixteen known analogues were identified.
• Trichiconlide G possesses a rare 1,2-seco phragmalin-type structure with a C-7/28 δ-lactone.
• Compounds 2, 3, and 4 feature a rare C-16/8 δ-lactone ring.
• No cytotoxicity was observed against A-549, HepG2, 5-8F, Siha, and SCC-4 cell lines at 40 μM.
• Compounds 16 and 17 exhibited moderate anti-inflammatory activity (IC50 values 28.45 ± 2.51 μM and 22.66 ± 2.01 μM, respectively).

Conclusions:

• The study expands the known diversity of limonoids from Trichilia connaroides.
• The identified compounds, particularly those with rare lactone rings, contribute to the understanding of limonoid structural variations.
• While lacking cytotoxic effects, specific isolates demonstrate potential as anti-inflammatory agents, warranting further investigation.