Improving the Antioxidant Properties of Calophyllum inophyllum Seed Oil from French Polynesia: Development and Biological Applications of Resinous Ethanol-Soluble Extracts
Abstract
Tamanu oil (TO) from Calophyllum inophyllum L. has long been used for its numerous properties in traditional medicine. To uncover the antioxidant and pharmacological activities of the complex pool of constituents gathered in the resin part of TO, extraction with methanol and ethanol were undertaken to give MeTO and EtTO extracts, this latter being further partitioned into neutral (NTR) and acidic (ATR) fractions. Further LPLC/HPLC separations allowed identifying fifteen metabolites. For two of them contained in NTR, calanolide D and 12-oxocalanolide A, we report here their first identification from a natural source. Oil extracts, subfractions and metabolites were evaluated for their antioxidant, anti-inflammatory, antimicrobial (Staphylococcus aureus) and antimycobacterial (Mycobacterium tuberculosis H37RV) properties, and their protective and antiradical effects on tBuOOH-treated cells and UV-exposed rat skin slices. The findings demonstrated that NTR and ATR containing amounts of metabolites exhibited high antioxidant and anti-inflammatory activities as compared to crude TO and its deresinated lipid phase. Highest antimicrobial and antioxidant activities were shown in NTR, while ATR was more cytoprotective against oxidative stress in cells. All together, data suggest that ethanol-soluble TO fractions rich in phenols, flavonoids and pyranocoumarins are of great potential as antioxidant and antimicrobial materials from a natural renewable source.
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