title: Chemical composition, antimicrobial, antioxidant and cytotoxic activity of essential oils of Plectranthus cylindraceus and Meriandra benghalensis from Yemen.
abstract: The chemical composition, antimicrobial, antioxidant and cytotoxic activities of the essential oils isolated from the leaves of Plectranthus cylindraceus Hoechst. ex. Benth. (EOPC) and Meriandra benghalensis (Roxb.) Benth. (EOMB) were investigated. Sixteen compounds were identified in P. cylindraceus oil representing 94.5% of the oil content with thymol (68.5%), terpinolene (5.3%), beta-selinene (4.7%), beta-caryophyllene (4.0%), delta-cadinol (2.1%), and arcurcumene (1.7%) as the major compounds. In M. benghalensis oil, 12 compounds were identified, which made up 82.0% of the total oil. The most abundant constituents were camphor (43.6%), 1,8-cineole (10.7%), alpha-eudesmol (5.8%), caryophyllene oxide (5.8%), camphene (5.3%) and bomeol (3.4%). The antimicrobial activities of both oils were evaluated against five microorganisms with the disc diffusion test, the broth micro-dilution method and a semiquantitative bioautographic test. The most sensitive microorganisms for P. cylindraceus oil were S. aureus, B. subtilis, and C. albicans with inhibition zones of 38, 42, and 43 mm and MIC values of 0.39, 0.18, and, 0.18 microL/mL, respectively. M. benghalensis oil showed weak to moderate activity against the tested microorganisms. 2,2-Diphenyl-l-picrylhydrazyl (DPPH) assay was employed to study the potential antioxidant activities of both oils. The antioxidant activity of P. cylindraceus oil (IC50 34.5 microg/mL) appeared to be higher than that of M. benghalensis oil (IC50 935 microg/mL). At a concentration of 100 microg/mL, EOMB showed a stronger cytotoxic activity, with growth inhibition of 71% against HT29 tumor cells, than EOPC (18%).
authors.affiliation: PharmacognosyDepartment, Faculty of Pharmacy, Sana'a University, P.O. Box 13150, Sana'a, Yemen. alinasser9678@yahoo.com
authors.forename: Nasser A Awadh
authors.initials: NA
authors.lastname: Ali
authors.forename: Martina
authors.initials: M
authors.lastname: Wursterb
authors.forename: Annika
authors.initials: A
authors.lastname: Denkert
authors.forename: Norbert
authors.initials: N
authors.lastname: Arnold
authors.forename: Iman
authors.initials: I
authors.lastname: Fadail
authors.forename: Gamal
authors.initials: G
authors.lastname: Al-Didamony
authors.forename: Ulrike
authors.initials: U
authors.lastname: Lindequist
authors.forename: Ludger
authors.initials: L
authors.lastname: Wessjohann
authors.forename: William N
authors.initials: WN
authors.lastname: Setzer
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001713:Biphenyl Compounds / Q000737:chemistry; D019073:HT29 Cells; D006801:Humans; D019686:Lamiaceae / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry*; D010851:Picrates / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry*; D015006:Yemen
chemical_list: D000900:Anti-Bacterial Agents; D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D001713:Biphenyl Compounds; D009822:Oils, Volatile; D010851:Picrates; D010938:Plant Oils; C004931:1,1-diphenyl-2-picrylhydrazyl