Suberin fatty acids from outer birch bark: Isolation and physical material characterization

Jyrki Heinämäki, Minni M. Pirttimaa, Sami Alakurtti, Pauliina H. Pitkänen, Heimo Kanerva, Janne Hulkko, Urve Paaver, Jaan Aruväli, Jouko Yliruusi, Karin Kogermann

    Research output: Contribution to journalArticleScientificpeer-review

    17 Citations (Scopus)


    The isolation and physical material properties of suberin fatty acids (SFAs) were investigated with special reference to their potential applications as novel pharmaceutical excipients. SFAs were isolated from outer birch bark (OBB) with a new extractive hydrolysis method. The present simplified isolation process resulted in a moderate batch yield and chemical purity of SFAs, but further development is needed for establishing batch-to-batch variation. Cryogenic milling was the method of choice for the particle size reduction of SFAs powder. The cryogenically milled SFAs powder exhibited a semicrystalline structure with apparent microcrystalline domains within an amorphous fatty acids matrix. The thermogravimetric analysis (TGA) of SFAs samples showed a good thermal stability up to 200 °C, followed by a progressive weight loss, reaching a plateau at about 95% volatilization at about 470 °C. The binary blends of SFAs and microcrystalline cellulose (MCC; Avicel PH 101) in a ratio of 25:75 (w/w) displayed good powder flow and tablet compression properties. The corresponding theophylline-containing tablets showed sustained or prolonged-release characteristics. The physicochemical and bulk powder properties of SFAs isolated from OBB are auspicious in terms of potential pharmaceutical excipient applications.
    Original languageEnglish
    Pages (from-to)916-924
    JournalJournal of Natural Products
    Issue number4
    Publication statusPublished - 28 Apr 2017
    MoE publication typeA1 Journal article-refereed


    This research was supported by the European Social Fund’s Doctoral Studies and Internationalisation Programme DoRa and GREASE Woodwisdom-ERANET (Tekes decision 40375/11). This work is part of the ETF grant project no ETF7980 and IUT34-18. The Estonian Ministry of Education and Research is acknowledged for financial support.


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