In vitro availability of kaempferol glycosides from cream formulations of methanolic extract of the leaves of Melilotus elegans

In Ethiopian traditional medicine, Melilotus elegans Salzm. ex Ser. (Leguminosae) is used for the treatment of haemorrhoids and lacerated wounds. In view of its wide spread use and proven anti-inflammatory activity, 80% methanolic extract of the leaves was formulated into creams. HPLC/UV and MS studies revealed the presence of flavonoids, of which kaempferol was the major aglycone. Quantitative estimation of kaempferol in the hydrolyzed extract as determined by HPLC/UV was found to be 16.3±0.93 μg/mg (n=6, range) of extract. The in vitro release profiles of kaempferol glycosides (quantified as kaempferol equivalent) from the cream formulations in a multilayer membrane system indicated that a lipophilic cream of the extract provides higher release of kaempferol glycosides than hydrophilic and amphiphilic ones. Over a study period of 4 h, the lipophilic cream released 66±5.70% of kaempferol glycosides, while the hydrophilic and amphiphilic creams resulted in 55±2.77 and 38±2.30% release, respectively.