Cementitious Chemical Properties in Parkia biglobosa Fruit Husk Extract: Unpacking Chemical Content in Indigenous Technology

One important non-timber forest product derived from Parkia biglobosa fruit husk is the extract used in indigenous building technology. Therefore, water and ethanol extracts of the fruit husk were assessed. Methods used were Sohxlet extraction, solubility tests, fractionation, HPLC, TLC, IR, and phytochemical screening. Water was identified as a more efficient solvent for the extraction of the husk. The average percent yield of extract was 37.77% using water, 30.83% using ethanol and 8.53% using water after ethanol extraction. The storage period (after harvest) of husk did not influence the mass of extract obtained. From the HPLC analyses, there were at least three classes of phenolic glycosides, one class of alkaloids, and two of the same or any two different classes of phenolic acids, flavonols and/or proanthocyanidins observed in the extract. The components of the extract are moderately polar, and associated together in minimum groups of two on TLC plates. A 2:1 mobile phase mixture of ethanol to water produced high Rf of 0.96 and 0.67 in the aqueous extract, and 1.0 in the strong acid fraction. 2:1 ethylacetate /chloroform mobile phase mixture produced the lowest retention factors (0.06) as well as separations. The strong acid fraction had at least three components; the weak acid fraction had four; three in the basic fraction, and four in the neutral fraction. IR spectra-based suspected species included –OH of alcohols and phenols, -NH of amines and amides, C-H of saturated hydrocarbons and aromatics, C=C of alkenes and aromatics, C=O of the carbonyls, and aromatic rings. These are also functional groups associated with polyphenols and alkaloids. The extract contained tannins, flavonoids, anthraquinones, saponins, anthraquinone glycosides and alkaloids identified in phytochemical screening. Some of the components have cementitious character and could be useful in developing mud based building technology.