Digital Scholarship and Initiatives

The author expresses concern that plants with medicinal value have been used as folk remedies before they were evaluated scientifically, but worldwide deforestation may wipe out medicinal and novel species before they can be put to widespread use. He believes, therefore, that medicinal and novel plants should be collected and evaluated quickly so that action can be taken to prevent their loss.

Burke talked with Lumbee people and was able to identify forty plant species and one lichen genus with potential medicinal value. After performing literature searches, he narrowed the focus of his research to Hexastylis arifolia. Hexastylis arifolia, known to Lumbee healers as heartleaf, has been used for flavoring and perhaps as a curative agent in tonics to treat lung trouble, heart trouble, and earache. It is in the aristolochiaceae (birthwort) family.

Burke examined the potential medicinal value of this plant by screening root extracts for antioxidant or antibiotic activity. He performed bioassay-guided fractionation to isolate five compounds. He then purified the compounds using silica gel column chromatography, preparative thin layer chromatography, and semi-preparative HPLC. He obtained full NMR data as well as UV-Vis and IR spectra for these compounds:

• costunolide
• safrole
• asarone
• 2,4,5-trimethoxybenzaldehyde
• novel isomers

  Tables show the full NMR data for each of the above compounds.

  The GC-MS detected several additional compounds; they were identified using a NIST spectral library. High quality spectral matches were obtained for some. A table lists those compounds not previously identified in extracts of Hexastylis arifolia.

  In the following paragraph, Burke provides an overview of the findings of his research:

  In summary, two new bioactive isomers (1a and 1b) were isolated and purified from the root extract of Hexastylis arifolia. The discovery of known germacranolide costunolide (2) in the root extract of Hexastylis arifolia is the first known report of this biological source for the compound (Figure 5). The presence of known phenylpropanoids, safrole (3) and asarone (4) in Hexastylis arifolia root extracts (reported previously by Hayashi) has been confirmed by high field NMR analysis of the purified compounds. The presence of known phenylbutanoid, 2,4,5-trimethoxybenzaldehyde (5) in the root extract of Hexastylis arifolia is reported for the first time (Figure 5). The presence of this range of bioactive compounds in Hexastylis arifolia validates and perhaps explains the use of this plant in Lumbee traditional medicine. The activities exhibited by known and novel compounds are not the same as those attributed to the herb by the Lumbee, however. This is probably a reflection of the bioassays adopted in this study, but likely also indicates the presence of other as yet undiscovered compounds in these extracts. Assay systems specific to cardiovascular and muscular disease may provide evidence of the activities described by folklore. Since only a handful of the multitude of compounds present in Hexastylis arifolia root extract were purified in this study, it is possible that other compounds may be responsible for the activity described by folklore. (Quoted from pages 35 and 38).