bark unclassified drug 18 Article 15 plant extract 14 drug isolation 13 controlled study 12 Plant Bark 11 chemistry 11 nonhuman 11 drug structure 10 IC50 9 plant stem 8 Acetylcholinesterase 7 Molecular Structure 7 isolation and purification 7 proton nuclear magnetic resonance 7 antiinflammatory activity 6 antioxidant 6 cholinesterase inhibitor 6 heteronuclear multiple bond correlation 6 human 6 nuclear magnetic resonance spectroscopy 6 Anti-inflammatory 5 Antioxidant 5 Plant Stems 5 antiinflammatory agent 5 antioxidant activity 5 article 5 carbon nuclear magnetic resonance 5 chemical structure 5