Studies on the chemical composition and biological activity of essential oils and extractive of cymbopogon nardus

Norzahir, Sapawe (2008) Studies on the chemical composition and biological activity of essential oils and extractive of cymbopogon nardus. [Final Year Project Report] (Unpublished)

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Abstract

Extractive and essential oils isolated from Cymbopogon nardus have been studied. Leaves, stems and roots of Cymbopogon nardus was extracted using solvent in order of increasing polarity starting with hexane, followed by dichloromethane, chloroform, ethyl acetate and methanol. The hexane crude extracts of leaves gave the highest yield (5.30% w/w) while ethyl acetate of stem gave lowest yield (0.28%). Further purification using column chromatography on the hexane and dichloromethane partition attended four semi-pure compounds. All the semi-pure compound were subjected to FTIR, GC-FID, GC-MS and melting point. Based on the analyses, none of the compounds was pure. The essential oils from the leaves, stems and roots of Cymbopogon nardus were isolated using hydrodistillation method and analyzed by GC-FID. The percentage yield of the essential oils ranged between 1.86 - 5.54 % and leaves oil gave the highest yield. The major composition of Cymbopogon l1ardus leaves were borneol (29.4%), isopulegyl acetate (19.2%), benzothiazole (9.3%) and a-curcumene (7.6%), while the major constituent of stems were nonadienol (13.7%), phenyl cyanide (7.8%), oxo-B-ionne (7.5%), butyl laurate (6.6%), B-elemene (6.3%) and 1O-epi-y-eudesmol (5.1%). The roots oil of Cymbopogon nardus was rich in 12-methyltridecanal (13.9%), B-sesquiphellandrene (9. 1 %) and B-bisabolol (8.0%). Toxicity test against larvae of Artemia salina showed that none of the crude extract was toxic. Meanwhile, the essential oil showed significant toxicity at concentration of 100 ppm. Based on the bioassay, the stems oil gave LC50 of 100 ug/mL, roots oil LC50 of 100 ug/mL while the leaves oil with LC50 >100 ug/mL. Insecticidal activity against termite, Nasutitermes spp. showed that the crude hexane of the roots gave highest termiticidal activity against termite with LC50 <0.1%. The essential oils of the Cymbopogon nardus showed strong termiticidal activity in a short time about 2 - 4 hours with LC50 <0.1 %.

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