Chemistry and Antimicrobial Activity of the Essential Oils from Ripe and Unripe fruits of the FijianMorinda citrifolia(noni/kura) Rubiaceae

Abstract The volatile compounds, obtained by steam distillation of the ripe and unripe fruits of the Fijian variety of Morinda citriflora, have been investigated. This species, known in Fiji as noni/kura and used in the preparation of the commercial noni beverage, gave octanoic and hexanoic acids as its major volatiles. From unripe fruit, the two principal components were octanoic acid (89.7 %) and hexanoic acid (3.6 %). From ripe fruits there was less acid; octanoic acid (60.2 %) and hexanoic acid (16.3 %). There were a series of 3-methylbut-3-en-1-yl esters (butyrate, hexanoate, octanoate and decanoate) in amounts up to 4 % in the ripe fruits. Also present were a series of methyl ester of these acids. Terpenes were virtually absent from the oils. Both the ripe and unripe fruit volatiles showed similar antimicrobial activities, when tested with five microbes signaling that the active volatile components were probably the major alkanoic acids. Key words: Fijian noni/kura Morinda citrifoliaGC-MSoctanoic acidhexanoic acid3-methylbut-3-en-1-yl estersalkanoic acids and estersBacillus subtilisEnterococcus faecalisStaphylococcus aureusSalmonella typhimuriumPseudomonas aeruginosaantimicrobial activity