Hemi-synthetic reactions of some flavonoids and saponin isolated from the stem bark of Albizia adianthifolia (Schumach) W. Wight (Mimosaceae) and highlighting their antiradical properties of reaction products

Hemi-synthetic reactions of some flavonoids and saponin isolated from the stem bark of Albizia adianthifolia (Schumach) W. Wight (Mimosaceae) and highlighting their antiradical properties of reaction products
Kikwainoh Alphonse Panyere, University of Dschang, correspondent: apanyere@gmail.com
INTRODUCTION: Natural products and their semisynthetic derivatives continue to be an important source of potential drug leads. Antioxidant could be used for heart disease, diarrhea, urinary issues, and blood reviver/tonic. In this study, we reported four hemi synthetic reactions performed on two flavonoids: kaempferol and quercetin and a saponin adianthifolioside GS1, isolated from Albizia adianthifolia (Schumach) W. Wight, a Cameroonian medicinal plant widely used in the treatement of malaria, diarrhea, amoebiasis, and vision disturbances and highlight their antiradical properties.METHODOLOGY : Kaempferol was allylated using allylbromide to obtained two reaction products KA1 and KA2. For the prenylation on quercetin using prenyl bromide, five products coded QP1 to QP5 were obtained. The reaction products AARcH1 and AARcH2 on one hand and AARcA1 to AARcA6 on the other hand were obtained after the reaction of hypobromination using bromine water and acetylation on adianthifolioside GS1 using acetyl anhydride respectively. Structure identification was done by spectroscopic analyses and comparison with published data.RESULTS: The hypobromination product, AARcH1 was identified as 3-O-β-D glucopyranosyl)-12-bromo-13-hydroxyoleanolic acid. The antiradical tests were carried out using a solution of 2,2-diphenyl-1-picrylhydrazyl, the two products of allylation, and one product of prenylation QP5, showed showed potential actiradical activities. Kaempferol and quercetin also showed significant potentials of antiradical compound. In both cases the products were observe to have less antiradical activities compared to the substrates. For the saponin’s hemisynthetic products, none of them showed potential antiradical activities. CONCLUSION: Hemisynthetic products were obtained from, kaempferol, quercetin and, 3-O-α-L-arabipyranosyl-(1→6)-β-D-glucopyranosyl}oleanolic acid. These hemisynthetic products showed potential antiradical activities that vary from those of the substrate.
Keywords: Albizia adianthifolia, flavonoids, saponin, hemisynthesis, antiradical activities