Lipophilic and polar extracts in the cork-rich bark of the Miombo species Parinari curatellifolia

Abstract

AbstractThe Miombo species Parinari curatellifolia has a bark with a cork-rich rhytidome that was studied here for the first time regarding extract yields and composition, using the complete rhytidome and also the separated cork fraction. The objective was to analyse their potential as sources of extracts with antioxidant activities aiming at increasing the species’ valorization and our knowledge on cork-rich barks.The content in total extractives was 6.1% and 8.4% in rhytidome and cork, respectively, with the lipophilic extracts soluble in dichloromethane corresponding to 23% and 38% of the total extracts, respectively. In cork, triterpenes and sterols were the main families of lipophilic components (58.9% and 20.8% of all compounds, respectively) while the rhytidome lipophilic extracts had a much higher content of long-chain lipids, including alkanoic acids and ɑ,ω-diacids (28.8% and 7.0%, respectively), with terpenes representing 27.7% and sterols 8.4% of all compounds. Aromatics were also present in significant amounts of 12.1%. Triterpenes included compounds known for various therapeutic properties, e.g. betulinic acid, corosolic acid, maslinic acid and ursolic acid, thereby explaining the use of P. curatellifolia in traditional medicine. Ethanol-water extracts contained phenolics, flavonoids, and tannins, and showed low (cork) or good (rhytidome) antioxidant properties. The outerbark of P. curatellifolia is therefore a potential source of bioactive compounds.