DES/Extraction and Process Optimization of Callistemon citrinus (Curtis) Skeels Essential Oil

Area of Science:

• Phytochemistry
• Natural Product Chemistry
• Analytical Chemistry

Background:

• Callistemon citrinus essential oil is a complex natural product.
• Extraction efficiency and chemical profile are influenced by process parameters.
• Metal ion pretreatment effects on essential oil composition are not fully understood.

Purpose of the Study:

• To optimize ultrasonic-assisted hydrodistillation for Callistemon citrinus essential oil extraction.
• To investigate the impact of metal ion pretreatment on the essential oil's chemical profile.
• To identify optimal extraction conditions and analyze compositional variations.

Main Methods:

• Systematic optimization using steepest ascent and response surface methodology (RSM).
• Extraction parameter optimization: heating time, heating power, and ultrasonic treatment time.
• Chemical analysis using Gas Chromatography-Mass Spectrometry (GC-MS) and Principal Component Analysis (PCA).

Main Results:

• Optimized conditions: 57 min heating, 563 W power, 23 min ultrasonic treatment, yielding 0.8 mL/kg essential oil.
• Metal ion pretreatment (Sr²⁺, Ca²⁺) increased relative abundance of monoterpenoids.
• PCA confirmed distinct chemical profiles based on ion pretreatment.

Conclusions:

• Ultrasonic-assisted hydrodistillation can be effectively optimized for Callistemon citrinus essential oil.
• Divalent metal ions selectively influence the extraction of volatile compounds.
• Ion-assisted extraction offers a method to modulate essential oil composition.