~ 312 ~ Journal of Pharmacognosy and Phytochemistry 2017; 6(2): 312-319 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2017; 6(2): 312-319 Received: 24-01-2017 Accepted: 25-02-2017 Amal A Al-Gendy Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, 44519, Zagazig, Egypt Fatma A Moharram Department of Pharmacognosy, Faculty of Pharmacy, Helwan University, 11795, Cairo, Egypt Mohamed A Zarka Department of Pharmacognosy, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), 6 th October City, Giza, Egypt Correspondence Amal A Al-Gendy Department of Pharmacognosy, Faculty of Pharmacy, Zagazig University, 44519, Zagazig, Egypt Chemical composition, antioxidant, cytotoxic and antimicrobial activities of Pimenta racemosa (Mill.) J.W. Moore flower essential oil Amal A Al-Gendy, Fatma A Moharram and Mohamed A Zarka Abstract Hydrodistilled essential oil obtained from Pimenta racemosa fresh flower was analyzed by GLC-MS. Fifty two components were identified, including 3.14% monoterpenes, 94.85% oxygenated monoterpenes and 0.42% oxygenated sesquiterpenes where 1,8-Cineole (75.4%) and linalool (9.08%) represented the major constituents. Quantification of the oil constituents was carried out using GLC-FID analysis where 1,8-cineole was detected at 428.3 μg/ml. The oil exhibited potential antioxidant activity when tested by DPPH radical scavenging assay where SC50=5.95 µg. The cytotoxic activity was evaluated using MTT assay compared with 1,8-cineole and doxorubicin. The oil showed significant activity against human carcinoma cell lines including colon (HCT-116), hepatic (HepG-2), lung (A-549) and intestinal epithelium (Caco-2) with IC50 values 1.71, 3.67, 1.35, and 2.63 µg, respectively. The oil cytotoxicity exceeded 1,8-cineole except for HepG-2. Additionally the antimicrobial activity was evaluated using agar disc diffusion and MIC where the oil exhibited the best activity against Bacillus subtilis and Geotrichum candidum with MIC=0.49 and 0.98 µg, respectively Keywords: Pimenta racemosa, essential oil, antioxidant, cytotoxic, antimicrobial 1. Introduction Essential oils are widely used for antimicrobial, antiparasitical, insecticidal and other medicinal activities. Additionally, they are used as flavour in cosmetics, pharmaceuticals and food industries [1] . Pimenta is a group of trees native throughout the Caribbean region. P. racemosa J.W. Moore is known as the “bay tree” and it has been naturalized to different African and Asian countries for its essential oil (EO) [2, 3] . Eugenol [4 -6] and 1,8-cineole [7, 8] were the main constituents identified in P. racemosa leaf EO which was recognized for its antioxidant [6, 9-11] , antimicrobial [12-18] , cytotoxic, virucidal [19] , mosquito larvicidal [20] , dysmenorrheal [21] , insecticidal [22] , nematicidal [23] and fumigant [24] activities. Although EO of P. racemosa leaf had attracted the researchers for many phytochemical and biological studies, there is only one report for flower EO composition and nothing was reported for its biological activities where Aboutabl et al., [25] stated that eugenol and isoeugenol were the major components of leaf and flower EO in P. racemosa cultivated in Egypt. The authors studied phenolic profile, anti-inflammatory, antinociceptive, anti-ulcerogenic and hepatoprotective activities of the leaves (under publication). In continuation of our work, we aim to investigate the EO composition of P. racemosa flower cultivated in Egypt, in addition to its antioxidant, antimicrobial and cytotoxic activities against different human cell lines. 2. Materials and methods 2.1. Plant material Flowers of P. racemosa (Mill.) J.W. Moore (syn. Myrtus caryophyllata, Lacq. Not L, P. acris Kostel) were collected from Zohreya garden, Giza, Egypt during the flowering stage in September 2014. Voucher specimen has been deposited at Orman botanical garden (00099CP @ 04-07-04-01). Identification was done by Dr. Trease Labib, former head specialist of plant taxonomy at Orman botanical garden, Giza, Egypt which is matching with the previous report for identification of this plant [26] . 2.2. Preparation of essential oil EO was obtained by hydro-distillation of fresh P. racemosa flowers (320 g) for 6 hours using a Clevenger-type apparatus. It was dried over anhydrous sodium sulphate and kept in sealed vial at -2 °C for analyses.