Chemical Study of Some Constituents of Albizia amara and Acacia mellifera

Abstract

The roots of Sudanese Albizia Amara were collected from the Al-Fulla forest in January, 2013 and Barks of Acacia mellifera were collected from Niala at west of the Sudan during October, 2013. Albizia Amara roots were extracted with 95% ethanol. Sequential solvent extraction using a number of solvents of varying polarity was used for the preliminary separation of flavonoids. Preliminary phytochemical screening of Albizia Amara roots indicated the presence of many phyto - components. All fractions showed positive test for alkaloids, saponins, phenolics, carbohydrate and flavonoids. The analysis of the volatiles of the crude and fractions was performed via Gas Chromatography - Mass Spectrometry (Volatile substances varied according to solvent).The ethyl acetate fraction yielded the highest amount of volatile components. In the cup plate agar diffusion assay, all fractions from Albizia Amara roots showed inhibitory activity against the Streptococcus mutans and Lacto bacillus.The ethyl acetate extract showed significant activity on Streptococcus mutans, while the n-butanol extract showed high activity on Lacto bacillus.Total antioxidant activity and total phenolic content of fractions were measured by different techniques: Ferric reduction activity potential ( FRAP),Total antioxidant capacity (TPC), 2, 2 - diphenyl-1-picrylhydrazyl (DPPH), and Cupric reducing antioxidant capacity (ORAC) methods.The results showed that the ethyl acetate fraction has significant antioxidant activity at a mean of (DPPH), 771.83 μg/g; (TPC), 3825.47 mg/g; (CUPRAC) 1902.686m μg/g. (FRAP), 538.09 μg/g .The chloroform fraction gave the lowest antioxidant activity at mean of: (DPPH) μg/g 24.28; (TPC) 719.48 μg/g, (CUPRAC)75.79 μg/g ; (FRAP) 132.35 μg/g. The ethyl acetate fraction of Albizia Amara and n-butanol fraction of Acacia mellifera were fractionated by paper chromatography and thin layer chromatography. These four compounds (three from Albizia Amara and one from Acacia mellifera ) were isolated.The structures of these IV isolates were elucidated via a combination of spectral techniques: UV, 1H-NMR and Mass speectroscopy.Furthermore, the four compounds were evaluated for their biological activity.The antibacterial activity was determined by the Well diffusion method against two human pathogens(Streptococcus mutans, Lacto bacillus).The anti-oxidant capacity was evaluated via two techniques (DPPH and FRAP) and significant results were obtained.