Chemical characterisation and biological evaluation of essential oils from selected aromatic plants

Ng, Seong Wooi (2010) Chemical characterisation and biological evaluation of essential oils from selected aromatic plants. Masters thesis, Universiti Malaysia Sabah.


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Essential oils are natural volatile substances that can be found in a variety of aromatic plants especially spices. This study was performed to provide data and compare the chemical composition, anti-oxidation, anti-microbial, mosquito repellency activities and toxicity of essential oils extracted from some common aromatic plants from the family of Lauraceae and Zingiberaceae namely Cymbopogon nardus, Cymbopogon citratus, Cinnamomum iners, Zingiber officinale, Curcuma longa, Hedychium coronarium, Alpinia galanga, Kaempferia galanga, and Etlingera punicea using a hydrodistillation method. The essential oils yielded range from 0.82 to 1.88%, and consisted of monoterpene,• monoterpenoid, sesquiterpene and sesquiterpenoid as the dominant constituents as analysed using a gas chromatography-mass spectrometry. The C. iners essential oil demonstrated the most potent anti-oxidation activity as evaluated using a DPPH free radical scavenging assay, possibly due to the present of eugenol as the major component. The anti-microbial property was evaluated against both Gram-positive bacteria [Bacillus cereus (6 43/04 6) and Staphylococcus aureus (S 277)] and Gram negative bacteria [Escherichia coli (E 91/026), Salmonella typhimurium (S 1000) and Pseudomonas aeruginosa (ATCC 10145)] using a disc-diffusion method. In general, the essential oils (C nardus, C citratus, C iners, Z officinale, A. galanga and E. punicea) containing high abundance of terpene, terpenoid, and fatty alcohols exerted potential anti-microbial effects against the Gram-positive bacteria with inhibition range from 8.72 to 22.87 mm. The essential oils of C. nardus, C. citratus and Z. officinale exhibited potential activities against adult mosquitoes compared to the effectiveness of DEET (N, N-diethyl-3-methylbenzamide) at 500 and 1000 ppm. The acute (6 hour exposure) and chronic (24 hour exposure) toxicities of the essential oils were determined using a brine shrimp lethality assay. The results showed that C. iners was distinctively toxic (77.27 to 81.66 ppm and 26.42 to 39.92 ppm respectively) while K. galanga exhibited weak toxicity (995.41 to 1169.50 ppm and 283.79 to 321.37 ppm respectively). In conclusion, the essential oils belong to the species in Laureceae family generally were more bioactive than those in the Zingiberaceae. These essential oils may be beneficent as natural ingredients for functional foods, perfumery and pharmaceutical products.

Item Type: Thesis (Masters)
Uncontrolled Keywords: essential oil, aroma plant, spice, chemical composition, anti-oxidant, anti-microbial, mosquito repellency activities, toxicity of essential oil extracted, functional food, perfumery, pharmaceutical product
Subjects: Q Science > QK Botany
Divisions: SCHOOL > School of Science and Technology
Date Deposited: 15 Jul 2013 13:56
Last Modified: 11 Oct 2017 15:11

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