Optimization of Microwave-Assisted Extraction Process of Callicarpa candicans (Burm. f.) Hochr Essential Oil and Its Inhibitory Properties against Some Bacteria and Cancer Cell Lines

Callicarpa candicans (Burm. f.) Hochr. (Callicarpa cana L.) is a medicinal plant that is distributed mainly in the tropics and subtropics of Asia and finds a wide range of uses in traditional medicine. In this study, we attempted and optimized the microwave-assisted hydro-distillation (MAHD) process to obtain essential oil from the leaves of C. candicans. In addition, the obtained oil was analyzed for volatile composition by gas chromatography–mass spectrometry (GC-MS) and assayed for bioactivity against several bacteria and cancer cell lines. To optimize the extraction process, response surface methodology (RSM) in combination with central composite design (CCD) was adopted. Experimental design and optimization were carried out with respect to three experimental factors including the ratio of water to raw material, extraction time, and microwave power. The optimal extraction conditions were obtained as follows: water to raw material ratio of 6/1 (v/w), extraction time 42 min, and microwave power 440 W. Composition determination of the obtained C. candicans essential oil indicated the presence of predominant components including caryophyllene <b-> (10.45%), cadinene <d-> (10.28%), gurjunene <a-> (8.95%), muurolene <g-> (8.92%), selinene <a-> (7.06%), selinene <b-> (5.59%), and copaene <a-> (5.40%). In comparison with the essential oils obtained via traditional hydro-distillation method, the essential oil extracted by MAHD exhibited superior anti-proliferative activity on all tested cancer cell lines. Current results imply that the MAHD is capable of recovering biologically-active natural products of greater quantity than that recovered by the conventional distillation