Five new phenolic compounds from Dendrobium aphyllum.

Area of Science:

• Natural Product Chemistry
• Pharmacology
• Medicinal Chemistry

Background:

• Dendrobium aphyllum is a traditional medicinal plant.
• Investigating its chemical constituents may reveal novel bioactive compounds.

Purpose of the Study:

• To isolate and characterize new chemical compounds from Dendrobium aphyllum stems.
• To evaluate the biological activities of the isolated compounds, including nitric oxide inhibition and antioxidant capacity.

Main Methods:

• Isolation of compounds using chromatographic techniques.
• Structure elucidation through extensive spectroscopic analyses (NMR, MS).
• Determination of absolute configuration via single crystal X-ray diffraction and quantum calculations.
• In vitro assays for nitric oxide production inhibition and DPPH radical scavenging activity.

Main Results:

• One new phenanthrene, aphyllone A (1), and four new bibenzyl derivatives, aphyllone B (2) and aphyllals C-D (3-5), were identified.
• Nine known compounds (6-14) were also isolated.
• Compounds 6, 8, and 14 demonstrated significant inhibition of nitric oxide production (32.48-38.50%) in LPS-stimulated RAW264.7 cells at 25 μM.
• Compound 2 exhibited strong DPPH radical scavenging activity (87.97%) at 100 μg/mL.

Conclusions:

• The chemical investigation of Dendrobium aphyllum yielded novel phenanthrene and bibenzyl derivatives.
• The isolated compounds possess notable anti-inflammatory and antioxidant properties.
• These findings support the ethnobotanical use of Dendrobium aphyllum and highlight its potential as a source for new therapeutic agents.