Chemical Compositions of Dialium guineense Willd. Leaf, Stem-bark and Fruit Essential Oils

Abstract

Aims: We report chemical composition of three essential oils from leaf, stem bark and fruit parts of Dialium guineense [Fabaceae], which we studied. D. guineense is a Nigerian fruity plant utilized widely in treatment of jaundice, ulcer, eye and heart problems, as antimicrobial and anti-malaria in ethno-medicine, also as dietary supplement. Its fruits, which are edible, possess sweet to sour astringent flavorings enjoyed in beverages, for quenching thirst and refreshing. Methodology: The volatile essential oils were obtained by hydro-distillation, using an all-glass apparatus adapted to British Pharmacopeia specifications and gave good yields of 0.06 to 0.10%, which we studied using GC and GC-MS.  Results: Twenty out of twenty-five compounds, representing 92.91% of the leaf oil were characterized, while eighteen and thirteen out of twenty-one and eighteen compounds were identified in stem-bark and fruit oils, representing 85.65% and 81.44% of each respectively. Most abundant compounds were cis-3-hexenyl butanoate in leaf, and trans-δ-9-octadecenoic acid in both stem-bark, and fruit essential oils. Dominant classes of compounds (%) in leaf oil were esters (56.86), terpenoids (18.27) and acids  (11.20); stem bark had mostly acids (57.41), esters (19.82) and terpenoids (3.05); most abundant in fruit oil were acids (65.79), hydrocarbons (8.56) and esters (3.42). Acids and esters dominated the 3 essential oils of D. guineense, with appreciable amounts of terpenoids and hydrocarbons in the three oils. Conclusion: We present chemical compositions of three essential oils of D. guineense Willd a Fabaceae, which has not been reported in literature. Presence of high oxygenated compounds (esters, acids, alcohols and terpenoids) in the three oils, are important quality determining factor, as well as responsible for flavoring and pharmacological properties, some of these have been highlighted here. Results of our study reveal the rich chemical compositions of D. guineense essential oils, which have long been utilized for traditional purposes.