BIOACTIVITY GUIDED SEPARATION OF RAW TURMERIC (Curcuma longa)

The powdered dry rhizome of the plant Curcuma longa, commonly known as turmeric, has been used for centuries as a traditional medicine to treat inflammatory diseases. Identification and characterization of the active compounds of turmeric is subjective and very few official methods of analysis are available in the literature. In order to test the anti-inflammatory activity, an in vitro test system has been established. HL-60 cells were differentiated and exposed to lipopolysaccharide (LPS) from E.coli (1 μg/ml) in the presence or absence of botanical compounds for 24 hrs. Supernatants were collected and analyzed for the production of tumor necrosis factor alpha (TNF-α) and prostaglandin E 2 (PGE 2 ) by standard ELISA assays. In order to verify the amount and identity of active components in the raw turmeric samples, analytical and preparative HPLC methods were developed. Bulk raw powdered turmeric rhizomes were obtained from two different commercial sources. These samples were subjected to various aqueous and organic extractions and the resulting fractions were analyzed by HPLC. None of the aqueous extracts expressed biological activity, but the crude organic extracts were capable of inhibiting LPS induced TNF-α (IC 50 = 15 and 25 μg/ml) and PGE 2 (IC 50 = 1 μg/ ml) production. One of the crude organic extracts was subjected to further separation using preparative HPLC and each of the resulting ten fractions was tested as described previously. These fractions had differing biological activity, ranging from no activity to IC 50 < 1 μg/ml. Additional analytical methods were developed to further separate the most active fractions to test for antiinflammatory activity.