| || || Medicinal plants -- Fiji|
| || || Whitefly control and anti-microbiological activities of essential oils from medicinal plants found in Fiji Islands|
Author: Chand, Ravneel Rajneel
Institution: University of the South Pacific.
Subject: Materia medica, Vegetable -- Fiji, Essences and essential oils -- Therapeutic use -- Fiji, Medicinal plants -- Fiji
Call No.: Pac RS 185 .F5 C43 2016
Copyright:10-20% of this thesis may be copied without the authors written permission
Abstract: A variety of plant materials contain essential oils that have extensive bioactivity properties. These properties are attributed to the chemical composition of essential oils. In the current research, chemical composition, whitefly control and antimicrobiological activities of essential oils from five medicinal plants found in Fiji; Cananga odorata (Makasoi), Murraya koenigii (L) Spreng (Curry leaves), Euodia hortensis forma hortensis (Uci), Ocimum tenuiflorum L (Tulsi) and Cymbopogon citratus (Lemon grass) were investigated. Firstly, the selected essential oils were analysed using Gas Chromatography Mass Spectrometry (GC-MS). The identified compounds were classified into groups. For the biological activities, different concentrations of essential oil solutions (0.25%, 0.5% and 5% (v/v)) were subjected to whitefly (Aleurodicus dispersus Russell) control activities in the form of fumigant and repellent test. Essential oils from O. tenuiflorum L were found to be best fumigant agents (100% mortality was achieved at 3 hours after exposure). The significant differences in the mortality for all the tested time (3, 6, 9, 12 and 24 hours) were only shown by O. tenuiflorum L and C. citratus essential oils, as the p<0.05 (5% level of significance). For the repellent test, none of the essential oils obtained 100% repellency based on Repellency index (RI%), however C. citratus and M. koenigii (L) Spreng were found to show the best repelling properties (RI%= 52, 52) compared to the other studied essential oils. In addition, the essential oils exhibited a very interesting antimicrobial profile when tested against five different bacteria and fungi at different concentrations (0.25%, 0.5%, 5%, 25%, 50% and 100% (v/v)). The essential oils from O. tenuiflorum L were considered to have strong antimicrobial properties as it showed the inhibition effect to all test bacteria and fungi. The trends in the chemical constituents of essential oils revealed that the phenolic and alcoholic compounds were major groups of contributors for the tested activities. Thus, these data suggested that essential oils from selected medicinal plants found in Fiji have potential to be employed in pesticide or anti-microbiological activities.