1. Lan-Ting GU IUFRO Division 5 Conference
5.07 Energy and Chemicals from Forest Biomass/Chemicals from Wood
National Taiwan University

2. Lan-Ting GU*, Shang-Tzen CHANG, Hui-Ting CHANG
Antibacterial and Antioxidant Activities of Ethanolic Extract from the Bark of Michelia formosana
Lan-Ting GU*, Shang-Tzen CHANG, Hui-Ting CHANG
School of Forestry and Resource Conservation, National Taiwan University
No. 1 Section 4, Roosevelt Road, Taipei 106, Taiwan
Tel ; Fax

3. Exploiting natural bactericide and antioxidant from M. formosana bark
Purpose
Exploiting natural bactericide and antioxidant from M. formosana bark
 Materials : Ethanolic extract of bark from M. formosana
Antibacterial activities : Broth microdilution method
Antioxidant activities : Total phenolic contents
DPPH free scavenging activities
Superoxide anion scavenging effects
Reducing power assays
Trolox equivalent antioxidant capacity (TEAC)

4. Results Specimen Bioactivities Antibacterial activities
Bark extract
Antibacterial activities
Exhibiting inhibitory effects on growth of Gram-positive bacteria and one Gram-negative bacterium (E. coli).
Antioxidant activities
Exhibiting the superior DPPH radical scavenging activity with an EC50 value of μg/mL. In the total antioxidant assay, bark extract also showed excellent performance with a TEAC value of 0.61 mM.
Four fractions
EF showed better antibacterial performance than the other fractions. Minimum inhibitory concentrations (MICs) of EF were 0.125, 0.1, 0.1, 0.25, 0.5 mg/mL against E. faecalis, S. aureus, S. epidermidi, MRSA (Methicillin-resistant S. aureus), and E. coli, respectively.
EF, BF, and WF were the most effective fractions with high DPPH radical scavenging activities (EC50 = 14.58, 11.34, and μg/mL), reducing power and TEAC values (0.80, 0.73, and 0.57 mM).

5. Conclusion
Bark extract of M. formosana can be utilized as an effective source for antibacterial and antioxidant agents.