The invention discloses a medicinal composition for treating diabetes and dyslipidemia obtained from the extract of Costus pictus D.Don having low oxalic acid containing hydroxycinnamic acid derivatives and flavonol mono-, di- and triglycosides along with small amounts of free flavonols. The said hydroxycinnamic acid derivatives consist of caffeic acid, p-coumaric acid, ferulic acid and sinapic acid and flavonol mono-, di- and triglycosides which includes quercetin, kaempferol and isorhamnetin with sugars glucose, galactose and rhamnose. Further it also provides a method of preparation of the same. The invention also discloses a method of treating mammals including human beings for medical conditions selected from diabetes dyslipidemia and related conditions for increasing anti oxidant potential for the regeneration of pancreatic beta cells and increasing the insulin secretogogue effect.
