Compositions of Thunbergia grandiflora Leaf and Root Essential Oils

Abstract

Fresh samples of leaves and roots of Thunbergia grandiflora were collected from forest- reserved area, Ibadan, Nigeria for extraction of their volatile oils. Hydro-distillation method was used in an all-glass Clevenger apparatus designed to British pharmacopeia specifications. It gave yields of 0.09% and 0.10% respectively. The oils were analyzed using gas chromatography [GC], gas chromatography-mass spectrometry [GC-MS] in University of Botswana. A total of thirty-eight compounds were identified in the leaf and root essential oils, twenty-seven compounds were identified in leaf oil, which account for 98.13% of it while seventeen identified compounds are responsible for 73.98% of root oil. Most abundant compounds in leaf oil are α-3-octanol (45.96%), 3,7 dimethyl 1,6-octadien-3-ol (13.22%) and 2- methoxy-3-(2-propenyl) phenol (8.36%). Dominant compounds in root oil are methyl salicylate (44.80%), 2,21,5,51-tetramethyl-1,11 - biphenyl (5.05%) and i-propyl hexadecanoate (2.87%). leaf oil is dominated by following classes of compounds (%); alcohols (68.58), carboxylic acid (4.01), aldehydes (12.90), ketones (5.18), esters (2.62), aromatics (0.66) and also sulphurates (0.45). Classes of compounds in root oil are esters (47.67), alcohols (2.64), carboxylic acids (0.55), aldehydes (7.69), sulphurates (1.61), aromatics (5.05) and alkane (5.02). The two oils contain alcohols and esters in good amounts. Our results indicate that alcohols, esters and aldehydes dominate Thunbergia grandiflora essential oils. We present important compounds in the leaf and root essential oils of Thunbergia grandiflora, which have not been reported earlier in literature.