Abstract

CHARACTERIZATION OF ESSENTIAL OIL OF GRAPEFRUIT (CITRUS PARADISI) BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY (GC-MS) AND ITS ANTIOXIDANT ACTIVITY BY 2,2-DIPHENYL-1-PICRYL-HYDRAZYL FREE RADICAL

Amna Shaheen, Aisha Naz, Zafar Iqbal*, Mian Habib ur Rehman Mahmood, Muhammad Khalid Saeed, Abeera Zafar, Shamaim Zafar

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Abstract

The essential oil from the fresh peels of grapefruit (Citrus paradisi) was extracted through the hydro-distillation method by using Dean Stark apparatus. The extracted essential oil was dried by using anhydrous sodium sulfate, resulting in a 0.2% yield. Gas Chromatography-Mass Spectrometry (GC-MS) analysis was conducted to identify the constituents present in the essential oil. The study showed presence of Limonene 88.15%, 5-Caranol,(1S,3R,5S,6R)-(-) 3.04%, 2-Furanmethanol 5-ethenyltetrahydro-α,α,5-trimethyl-,cis- 1.44%, 1,6-Octadien- 3-ol3,7-dimethyl- 1.43%, Caryophyllene 1.03%, 2-Isopropenyl- 5-methylhex-4-enal 0.98%, Terpinen-4-ol 0.94%, Naphthalene1,2,4a,5,8,8a-hexahydro-4,7-dimethyl-1-(1- methylethyl)-,[1S-(1a,4aβ,8aα)]- 0.60%, ethyl2-(5-methyl-5- vinyltetrahydrofuran-2-yl)propan-2-yl 0.57%, 2- Naphthalenemethanol 1,2,3,4,4a,5,6,7-octahydro-α,α,4a,8- tetramethyl-,(2R-cis)- 0.52%, n-Hexadecanoic acid 0.51%, alfa-Copaene 0.31%, 9,12-Octadecadienoic acid (Z,Z)- 0.27% and D-Limonene 0.11%. The antioxidant activity of essential oil was determined by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical and it was concentration dependent. The antioxidant activity of 56.5% was observed at a concentration of 100 μL of essential oil.

Keywords: Grapefruit; Peel; Hydrodistillation; Essential oil; GC-MS; Antioxidant; DPPH.