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Antioxidant Activity
of
Hypericum brachyphyllum
Tung Pham, Anita Rahman, Omar E. Christian
McNeese State University
Lake Charles, LA
1
Outline
 Introduction
 Antioxidants
 Hypericum brachyphyllum
 Objectives
 Antioxidant Activity
 Antibacterial Activity
 Future Works
2
Introduction
Importance of antioxidants:
 Reactive oxygen species (ROS) - cancer, hypertension,
neurodegenerative diseases, and aging
 Antioxidants: prevent free radicals (chemically unstable
and highly reactive) from harming healthy tissues
Fig. 1 – How antioxidants work
Fig. 2 – Antioxidant doing their job
Sayre, Lawrence M., George Perry, and Mark A. Smith: Oxidative Stress and Neurotoxicity. Chem. Res. Toxicol. 2008, 21,
172-188.
Sen, Saikat and Raja Chakraborty: The Role of Antioxidants in Human. ACS Symposium Series. Vol 1083; 2011. 1-37
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Introduction
4
Introduction
Hypericum brachyphyllum
(coastal plains St. John’s Wort):
 Used by many Native American
tribes to treat a variety of
conditions
R = H Clusianone
R = OH 18-hydroxy-clusianone
 Hypericum genus: polyphenolic
compounds (prenylated
benzophenones) - antioxidant
capacity
R = H 7-epi-clusianone
R = OH 18-hydroxy-7-epi-clusianone
Christian, Omar E.; Stewart McLean, William F. Reynolds, and Helen Jacobs: Prenylated Benzophenones from
Hypericum hypericoides. Natural Product Communications. 2008, 3, 1781-1786.
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Objectives
 Evaluate antioxidant activity of Hypericum brachyphyllum
aerial part and root extracts
 using MTT assay (3(4,5-dimethylthiazole-2-yl)-2,5diphenyltetrazolium bromide)
 Evaluate antibacterial activity of crude extracts
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Materials
7
Antioxidant Activity
Methods:
 MTT was dissolved in DMSO - 30 mg/mL
 Ascorbic acid (1 mg/mL to 30 mg/mL)
was reacted with MTT to obtain a
standard curve.
 Ascorbic acid in the solutions reacted
completely with MTT to form formazan
which absorbed at 570 nm.
 Excess MTT did not interfere with the
absorption of formazan.
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Antioxidant Activity
Ascorbic Acid
MTT
Formazan
9
Antioxidant Activity Results
Crude Extract
Root MeOH
Root EtOAc
Aerial MeOH
Aerial Acetone
Aerial Hexane
Concentration (ppm)
6,250
6,250
6,250
6,250
6,250
Absorbance (at 570 nm)
0.276
0.103
0.341
0.442
0.143
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Antioxidant Activity Results
Results and Discussion:
 Acetone extract of aerial parts displayed the most potent activity
 Hypericum genus is a rich source of benzophenones.
 Antioxidant potential of benzophenones is well known.
Dimitrina Zheleva-Dimitrova; Paraskev Nedialkov; Ulrich Girreser and Gerassim Kitanov. Benzophenones and
Flavonoids from Hypericum Maculatum and Their Antioxidant Activities. Natural Product Research. 2012, 26, 15761583.
Matsuhisa, Michiko et al. Benzoylphloroglucinol Derivatives from Hypericum scabrum. J. Nat. Prod. 2002, 65, 290-294.
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Antibacterial Activity
 Results and Discussion
 Inhibited on the Gram-positive
bacteria Staphylococcus aureus.
 The most potent: methanolic extract
of the roots
 The known metabolites of
hyperibone A to D inhibit MRSA in
S. aureus.
Crude Extract
Root MeOH
Root EtOAc
Aerial MeOH
Aerial Acetone
Aerial Hexane
Chloramphenicol
Concentration (mg/mL)
53.4
54.8
52.7
50.0
56.5
50.0
1) HBA-MeOH
2) HBA-Hexane
3) HBA- Acetone
4) HBR-ETOAc
5) HBR-MeOH
6) DMSO - Control
7) Chloramphenicol - Control
Zone of Inhibition (mm)
E. coli (Gram-)
S. aureus (Gram+)
8.0
2.0
2.5
1.5
1.5
12.0
12
Future Works
 Continue bioassay-directed purification of acetone extract
from aerial parts
 Separation and examination of methanol root extract for
antibacterial activity
H. brachyphyllum
Aerial Parts
Acetone Extract
H. brachyphyllum
Root
Methanol Extract
13
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Acknowledgement
We would like to thank
 Dr. Mark Merchant for his help and the use of his lab for
running the antibacterial bioassay
 Office of Research Services and Sponsored Programs
 McNeese State University
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