Chemical Profile of the Stem Extract of Costus afer (Bush Cane) from Imo State in Nigeria

Aim: The aim of the study was to investigate the chemical profile of the stem extract of Costus afer (Bush cane).

Methodology: Fresh stems of Costus afer were obtained from Obizi in Ezinihitte Mbaise Local Government Area of Imo State. The stem extract of Costus afer a medicinal important plant of the Costaceae were extracted with hot water (aqueous extraction) and proximate composition were determine through AOAC method. Fatty acids were determined through saponification and fatty acid methyl esters were thrice extracted from the mixture with redistilled n-hexane. The phytochemicals of the stem extract were determined by GC/MS analysis.

Results: Proximate composition of stems of Costus afer showed that it contained moisture (22.15%), crude fat (1.15%), ash (4.60%), crude protein (7.72%), crude fibre (9.40%) and carbohydrate (54.98%) while its calorific value is 261.15 kcal/100 g. Phytochemical analyses revealed the presence of alkaloids (70.59 mg/100 g) ranging from papaverine (44.72%) to narcotine (14.11%). Total flavonoids (28.29 mg/100 g) consisted mainly of myricetin (69.79%), quercetin (14.88%) and kaemferol (9.78%). The saponins (2.87 mg/100 mg) consisted mainly of sapogenin (39.20%), saponine (22.12%) and diosgenin (26.13%) while the glycosides (22.35 mg/100 mg) consisted mainly of costugenin (65.60%), digitoxin (18.73%), digoxin (6.28%) and salicin (4.76%). The fatty acid composition showed moderate concentrations of linolenic acid (32.27%), linoleic acid (25.90%), palmitic acid (25.48%) and low concentrations of oleic acid (7.11%) and stearic acid (6.37%).

Conclusion: Chemical studies on Costus afer have reported the presence of alkaloids, saponins, glycosides and flavonoids as the main constituents and were confirmed by phytochemical screening. As a rich source of bioactive compound coupled with the presence of the nutrients the stem of Costus afer studied can be seen as a potential source of food, drugs, fodder and a good source of important nutrients for livestock.