A Comparative Study of Phytochemical Constituents and Bioactivity of n-Hexane and dichloromethane extracts of Juniperus oxycedrus subsp. macrocarpa and J. oxycedrus subsp. Oxycedrus

The genus Juniperus (Cupressaceae) includes many native plants of the Mediterranean regions. Juniperus oxycedrus L. is a shrub or small tree native across the Mediterranean region from Morocco and Portugal east to western Caucasus, growing on a variety of rocky sites from sea level up to 1600 m altitude [1]. According to the Flora Europea, J. oxycedrus L. includes three subspecies: subsp. oxycedrus, subsp. macrocarpa (Sibth. & Sm.) Ball. and subsp. badia (H. Gay) Debeaux. The search of new molecules for cancer therapy represents an area of great interest in which plants have an important and growing role. This study assessed and compared the chemical profile and the antioxidant and anti-proliferative activities of non polar extracts of Juniperus oxycedrus subsp. macrocarpa (Sibth. & Sm.) Ball. and J. oxycedrus subsp. oxycedrus from Italy. The aerial parts of both Juniperus subspecies were subjected to exhaustive macerations with n-hexane and dichloromethane. Obtained extracts were investigated for their chemical profile by gas chromatography (CG) and gas chromatography-mass spectrometry (GC-MS) and their potential antioxidant properties using four bioassays, namely 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Activity Power (FRAP), and b-carotene bleaching assays [2]. The cytotoxic activity of extracts was evaluated using the Sulforhodamine B (SRB) assay against several cancer human cell lines (MCF-7, MDA-MB-231, A549 and COR-L23 cells) [3]. Monoterpenes and sesquiterpenes mainly characterized n-hexane extracts while diterpenes and fatty acids are the most abundant identified compounds in dichloromethane extracts. The n-hexane and dichloromethane extracts of J. oxycedrus subsp. oxycedrus showed the most promising cytotoxic activity against COR-L23 cell line with IC₅₀ values of 26.90 and 39.26 microg/ml, respectively. On the other hand, extracts of J. oxycedrus subsp. macrocarpa revealed a great radicals scavenging activity. Overall, results suggest both Juniperus subspecies as good source of potential antioxidants and anti-proliferative compounds.

[1] Orhan N., Orhan I.E., Ergun F. (2011). Insights into cholinesterase inhibitory and antioxidant activities of five Juniperus species. Food Chem. Toxicol. 49, 2307. [2] Tenuta, M.C., Brigitte Deguin, B., Loizzo, M.R., Dugay, A., Acquaviva, R., Malfa, G.A., Bonesi, M., Bouzidi, C., Tundis, R. (2020). Contribution of flavonoids and iridoids to the hypoglycaemic, antioxidant, and nitric oxide (NO) inhibitory activities of Arbutus unedo L. Antioxidants 9, 184. [3] Loizzo M.R., Tundis R., Statti G.A., Menichini F., Houghton P.J. (2005). In vitro antiproliferative effects on human tumor cell lines of extracts and jacaranone from Senecio leucanthemifolius Poiret. J. Pharm. Pharmacol. 57, 897.