Comparative Study of Essential Oils from Tunisian Pinus Halepensis Mill. by Hydrodistillation and Microwave-Assisted Processes: Chemical Composition and Antioxidant and Cytotoxic Potential against Prostate and Cervical Cancer Cells.

Abstract

Pinus halepensis Mill. is a Mediterranean aromatic plant largely used, in addition to its nutritional value, in traditional medicine as antiseptic, antifungal, antituberculotic, and antirheumatic. Thus, the objective of this work was to appraise the antioxidant and cytotoxic activity of the essential oil (EO) of P. halepensis from Tunisia on cancer cell cultures, along with chemical composition evaluation by GC-MS. To attain the best yield and also highest quality in extraction of the EOs, conventional hydrodistillation (HD) and novel microwave-assisted extraction (MAE) methods have been performed and compared. The antioxidant activity was evaluated through the inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH)• radicals. The cytotoxic activity in prostate cancer cells (LNCaP and PC3) and cervical cancer cells (HeLa) of EO was evaluated by the MTT assay and effect on the cell cycle by flow cytometry analysis. A total of 38 and 37 components were identified from HD (HD-EO)- and MAE (MAE-EO)-extracted EOs, respectively, which were dominated by hydrocarbon compounds (HD-EO = 86.65%; MAE-EO = 77.36%), especially monoterpenes (HD-EO = 32.11%; MAE-EO = 21.55%) and sesquiterpenes (HD-EO = 44.29%; MAE-EO = 61.32%). Both extracted EOs showed significant antioxidant activity, as shown by the inhibition of DPPH• radicals [IC50 (HD-EO) = 4102.30 ± 159.73 μg mL-1 and IC50 (MAE-EO) = 3430.13 ± 78.46 μg mL-1]. Also, the EOs exhibited substantial (p < 0.001) antiproliferative activities with G0-G1 arrest on PC3, LNCaP, and HeLa cells by yielding very low IC50 values more conspicuous in MAE-EO with respective IC50 values of 25.70 ± 6.58, 14.97 ± 3.21, and 14.55 ± 2.30 μg mL-1. This finding points out for the first time that the EO of P. halepensis Mill. from Tunisia can be an effective natural antitumor agent with more pronounced activity when extracted with the MAE method that, after further in vivo studies, can be harnessed as a putative phytopharmaceutical for prostate and cervical cancer treatment.