title: Chemical composition of essential oils and in vitro antioxidant activity of fresh and dry leaves crude extracts of medicinal plant of Lactuca Sativa L. native to Sultanate of Oman.
abstract: OBJECTIVE
  To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L. (L. sativa).
  
  
  METHODS
  The essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L. sativa (lettuce) grown in Sultanate of Oman by hydro distillation method. The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity (DPPH) method.
  
  
  RESULTS
  About 20 chemical compounds of different concentration representing 83.07% and 79.88% respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves as α-pinene (5.11% and 4.05%), γ-cymene (2.07% and 1.92%), thymol (11.55% and 10.73%), durenol (52.00% and 49.79%), α-terpinene (1.66% and 1.34%), thymol acetate (0.99% and 0.67%), caryophyllene (2.11% and 1.98%), spathulenol (3.09% and 2.98%), camphene (4.11% and 3.65%), limonene (1.28% and 1.11%) representing these major chemical compounds. However, some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including β-pinene, α-terpinolene, linalool, 4-terpineol, α-terpineol, o-methylthymol, L-alloaromadendrene and viridiflorene.
  
  
  CONCLUSIONS
  The chemical constituents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes, sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons. Therefore, the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant, antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases.
authors: School of Pharmacy, College of Pharmacy and Nursing, University of Nizwa, P. O. Box 33, Postal Code 616, Nizwa, Sultanate of Oman.
authors: Rahma Said Salim
authors: RS
authors: Al Nomaani
authors: Mohammad Amzad
authors: MA
authors: Hossain
authors: Afaf Mohammed
authors: AM
authors: Weli
authors: Qasim
authors: Q
authors: Al-Riyami
authors: Jamal Nasser
authors: JN
authors: Al-Sabahi
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D018545:Lactuca / Q000737:chemistry*; D009822:Oils, Volatile / Q000737:chemistry* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D009822:Oils, Volatile; D010936:Plant Extracts
keywords: Antioxidant activity; Clevenger apparatus; Durenol; Essential oil; GC-MS analyses; Lactuca sativa; Omani lettuce; Organic crude extracts; Soxhlet extractor; Thymol
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