Antioxidant Properties of Several Medicinal Mushrooms
JENG-LEUN MAU,*,†HSIU-CHING LIN,†AND CHIN-CHU CHEN‡
Department of Food Science, National Chung-Hsing University, 250 Kuokuang Road, Taichung 402,
Taiwan, Republic of China, and Biotechnology Center, Grape King Inc., 60 Lungkang Road, Sec. 3,
Chungli 320, Taiwan, Republic of China
Three species of medicinal mushrooms are commercially available in Taiwan, namely, Ganoderma
lucidum (Ling-chih), Ganoderma tsugae (Sung-shan-ling-chih), and Coriolus versicolor (Yun-chih).
Methanolic extracts were prepared from these medicinal mushrooms and their antioxidant properties
studied. At 0.6 mg/mL, G. lucidum, G. lucidum antler, and G. tsugae showed an excellent antioxidant
activity (2.30-6.41% of lipid peroxidation), whereas C. versicolor showed only 58.56%. At 4 mg/mL,
reducing powers were in the order G. tsugae (2.38) ∼ G. lucidum antler (2.28) > G. lucidum (1.62)
> C. versicolor (0.79). At 0.64 mg/mL, scavenging effects on the 1,1-diphenyl-2-picrylhydrazyl radical
were 67.6-74.4% for Ganoderma and 24.6% for C. versicolor. The scavenging effect of methanolic
extracts from G. lucidum and G. lucidum antler on hydroxyl radical was the highest (51.2 and 52.6%)
at 16 mg/mL, respectively. At 2.4 mg/mL, chelating effects on ferrous ion were in the order G. lucidum
antler (67.7%) > G. lucidum (55.5%) > G. tsugae (44.8%) > C. versicolor (13.2%). Total phenols
were the major naturally occurring antioxidant components found in methanolic extracts from medicinal
mushrooms. Overall, G. lucidum and G. tsugae were higher in antioxidant activity, reducing power,
scavenging and chelating abilities, and total phenol content.
power; scavenging effect; chelating effect; antioxidant components
Medicinal mushrooms; Coriolus versicolor; Ganoderma; antioxidant activity; reducing
Numerous physiological processes in living organisms oc-
casionally produce oxygen-centered free radicals and other
reactive oxygen species as byproducts. Oxidative damage caused
by free radicals may be related to aging and diseases, such as
atherosclerosis, cancer, and rheumatoid arthritis (1). Although
humans and other organisms possess antioxidant defense and
repair systems that have evolved to protect them against
oxidative damage, these systems are insufficient to totally
prevent the damage (2). However, the antioxidants in human
diets are of great interest as possible protective agents to help
human body reduce oxidative damage.
Recently, a multitude of natural antioxidants have already
been isolated from different kinds of plant materials such as
oilseeds, cereal crops, vegetables, fruits, leaves, roots, spices,
and herbs (3). Chinese herbs have been used for diet therapy
for several millennia. Some of them are alleged to exhibit
significant antioxidant activity (4, 5). Mushrooms are a tradi-
tional Chinese medicine and also commonly used as food.
Currently, three species of medicinal mushrooms are com-
mercially available in Taiwan, namely, Ganoderma lucidum
(Curtis: Fr.) Karsten (Ling-chih or reishi), Ganoderma tsugae
Murrill (Sung-shan-ling-chih), and Coriolus Versicolor (Fr.)
Quel. (Yun-chih or turkey tail).
These medicinal mushrooms are commonly used for phar-
maceutical purposes and as health foods. These medicinal
mushrooms were found to be medically active in several
therapeutic effects such as antitumor, immunomodulating, and
chronic bronchitis (6). The nutritional values and taste compo-
nents of these medicinal mushrooms were clearly studied (7).
Although research was focused on the therapeutic effects of
these medicinal mushrooms, little information is available about
their antioxidant properties. Our objective was to evaluate the
antioxidant properties of these medicinal mushrooms including
antioxidant activity, reducing power, scavenging effects on
radical, and chelating effects on ferrous ion. The contents of
potential antioxidant components of these medicinal mushrooms
were also determined.
MATERIALS AND METHODS
Mushrooms. C. Versicolor, G. lucidum, G. lucidum antler (in
varnished and forked shape), and G. tsugae were purchased, in a dried
form, at a local market in Taichung City, Taiwan. For each of four
types of mushrooms, three samples (∼50 g each) were randomly
selected and prepared for analyses. After a fine powder (20 mesh) was
obtained using a mill (Restsch Ultra centrifugal mill and sieving
machine, Haan, Germany), a subsample (5 g) was extracted by stirring
with 100 mL of methanol at 25 °C at 20g for 24 h and filtering through
Whatman no. 4 filter paper. The residue was then extracted with two
* Author to whom correspondence should be addressed (telephone 886-
4-2285-4313; fax 886-4-2483-3508; e-mail email@example.com).
†National Chung-Hsing University.
‡Grape King Inc.
6072J. Agric. Food Chem . 2002, 50, 6072−6077
10.1021/jf0201273 CCC: $22.00©2002 Am erican Chem ical Society
Published on Web 09/07/2002
additional 100 mL portions of methanol as described above. The
combined methanolic extracts were then rotary evaporated at 40 °C to
dryness. The dried extract was used directly for analyses of antioxidant
components or redissolved in methanol to a concentration of 20 mg/
mL and stored at 4 °C for further use.
Antioxidant Activity. The antioxidant activity was determined by
the 1,3-diethyl-2-thiobarbituric acid (DETBA) method (8, 9). To 50
µL of each mushroom extract (0.1-0.6 mg/mL) in methanol was added
50 µL of linoleic acid solution (Sigma Chemical Co., St. Louis, MO;
2 mg/mL in 95% ethanol). The mixture was incubated in an oven at
80 °C for 60 min and cooled in an ice bath. To the mixture were
sequentially added 200 µL of 20 mM butylated hydroxytoluene (BHT,
Sigma), 200 µL of 8% sodium dodecyl sulfate (SDS, Merck, Darmstadt,
Germany), 400 µL of deionized water, and 3.2 mL of 12.5 mM DETBA
(Aldrich Chemical Co., Milwaukee, WI) in sodium phosphate buffer
(pH 3.0). The mixture was mixed thoroughly, placed in an oven at 95
°C for 15 min, and then cooled with an ice bath. After 4 mL of ethyl
acetate was added, the mixture was mixed and centrifuged at 1000g at
20 °C for 15 min. Ethyl acetate was separated, and its fluorescence
intensity was measured in a Hitachi 650-40 spectrofluorometer with
fluorescence excitation at 515 nm and emission at 555 nm. The
antioxidant activity was expressed as the percentage of lipid peroxi-
dation with a control containing no mushroom extract being 100%. A
higher percentage indicates a lower antioxidant actiVity.
Reducing Power. The reducing power was determined according
to the method of Oyaizu (10). Each mushroom extract (0.5-4 mg/
mL) in methanol (2.5 mL) was mixed with 2.5 mL of 200 mM sodium
phosphate buffer (pH 6.6; Wako Pure Chemical Co., Osaka, Japan)
and 2.5 mL of 1% potassium ferricyanide (Sigma), and the mixture
was incubated at 50 °C for 20 min. After 2.5 mL of 10% trichloroacetic
acid (w/v; Wako) was added, the mixture was centrifuged at 200g for
10 min. The upper layer (5 mL) was mixed with 5 mL of deionized
water and 1 mL of 0.1% ferric chloride (Wako), and the absorbance
was measured at 700 nm in a Hitachi U-2001 spectrophotometer. A
solution with all reagents but the extracts was used as a blank. A higher
absorbance indicates a higher reducing power.
Scavenging Effect on 1,1-Diphenyl-2-picrylhydrazyl (DPPH)
Radical. Each mushroom extract (0.75-0.65 mg/mL) in methanol (4
mL) was mixed with 1 mL of methanolic solution containing DPPH
(Sigma) radical, resulting in a final concentration of 0.2 mM DPPH.
The mixture was shaken vigorously and left to stand for 30 min in the
dark, and the absorbance was then measured at 517 nm (11).
Scavenging Effect on Hydroxyl Radical. The hydroxyl radical
reacted with the nitrone spin trap 5,5-dimethylpyrroline-N-oxide
(DMPO, Sigma), and the resultant DMPO-OH adduct was detected
with an electron paramagnetic resonance (EPR) spectrometer. The EPR
spectrum was recorded 2.5 min after 200 µL of each mushroom extract
(4-16 mg/mL) in methanol was mixed with 200 µL of 10 mM H2O2
(Merck), 200 µL of 10 mM Fe2+(Sigma), and 200 µL of 10 mM DMPO
using a Bruker EMX-10 EPR spectrometer at the following settings:
3480 G magnetic field; 1.0 G modulation amplitude; 0.5 s time constant;
and 200 s scan period (12).
Chelating Effects on Ferrous Ion. Chelating effect was determined
according to the method of Shimada et al. (11). To 2 mL of the mixture
consisting of 30 mM hexamine (Wako), 30 mM potassium chloride
(Sigma), and 9 mM ferrous sulfate (Union Chemical Works, Hsinchu,
Taiwan) was added 2 mL of each mushroom extract (0.3-2.4 mg/mL)
in methanol and 200 µL of 1 mM tetramethyl murexide (TMM, Sigma).
After 3 min at room temperature, the absorbance of the mixture was
determined at 485 nm. A lower absorbance indicates a higher chelating
Determination of Antioxidant Components. Ascorbic acid was
determined according to the method of Klein and Perry (13). The dried
methanolic extract from medicinal mushrooms (20 mg) was extracted
with 10 mL of 1% metaphosphoric acid (Union) for 45 min at room
temperature and filtered through Whatman no. 4 filter paper. The filtrate
(1 mL) was mixed with 9 mL of 2,6-dichloroindophenol (Sigma), and
the absorbance was measured at 515 nm within 15 s. The content of
ascorbic acid was calculated on the basis of the calibration curve of
authentic L-ascorbic acid (Sigma).
?-Carotene was extracted and analyzed as described by Rundhaug
et al. (14). The dried methanolic extract from medicinal mushrooms
(20 mg) was extracted with a solution of 1% pyrogallol (Wako) in 10
mL of methanol/dichloromethane (1:1, v/v) for 45 min at room
temperature and filtered through Whatman no. 4 filter paper; the volume
was adjusted to 10 mL using the same solution. The filtrate was then
passed through a filter unit (13 mm, Lida Corp., Kenosha, WI) and
filtered using a 0.45-µm CA filter paper prior to injection onto a high-
performance liquid chromatograph (HPLC).
The HPLC system consisted of a Hitachi D-6200 pump, a Hitachi
L-5000 LC controller, a Rheodyne 7161 injector, a 20-µL sample loop,
a Hitachi D-2500 chromatointegrator, a Hitachi L-4000 UV detector,
and a Prodigy 5 ODS-2 column (4.6 × 250 mm, 5 µm, Phenomenex
Inc., Torrance, CA). The mobile phase was acetone/methanol/aceto-
nitrile, 1:2:2 (v/v/v), at a flow rate of 0.7 mL/min, and UV detection
was at 470 nm. The content of ?-carotene was calculated on the basis
of the calibration curve of authentic ?-carotene (Sigma).
Tocopherols were extracted and analyzed according to the method
of Carpenter (15). The dried methanolic extract from medicinal
mushrooms (50 mg) was suspended in 6 mL of pyrogallol (6% in 95%
ethanol) and 4 mL of 60% potassium hydroxide aqueous solution, and
the resulting mixture was saponified at 70 °C for 20 min. Deionized
water (15 mL) was added, and the mixture was extracted with 15 mL
of n-hexane. The organic layer was washed with deionized water to
neutral, dried over anhydrous sodium sulfate, and rotary evaporated to
dryness. The residue was redissolved in 5 mL of n-hexane and filtered
prior to HPLC injection in the same manner as in the ?-carotene assay.
The HPLC system was the same as for the ?-carotene assay. The
mobile phase was acetonitrile/methanol, 85:15 (v/v), at a flow rate of
1.0 mL/min, and UV detection was at 295 nm. The content of each
tocopherol was calculated on the basis of the calibration curve of each
authentic tocopherol (Sigma).
Total phenols were determined according to the method of Taga et
al. (16). The dried methanolic extract from medicinal mushrooms (20
mg) was dissolved in a solution of 5 mL of 1.3% HCl in methanol/
deionized water (60:40, v/v), and the resulting mixture (100 µL) was
added to 2 mL of 2% aqueous sodium carbonate solution. After 3 min,
100 µL of 50% Folin-Ciocalteau reagent (Sigma) was added to the
mixture. After 30 min of standing, absorbance was measured at 750
nm. The content of total phenols was calculated on the basis of the
calibration curve of gallic acid (Sigma).
Statistical Analysis. For methanolic extracts from mushrooms, three
samples were prepared for assays of every antioxidant attribute. The
experimental data were subjected to an analysis of variance for a
completely random design as described by Steel et al. (17) to determine
the least significant difference at the level of 0.05.
RESULTS AND DISCUSSION
Antioxidant Activity. Following the extraction with metha-
nol, four medicinal mushrooms had the yields of 3.97-9.16%
(Table 1). As compared to other specialty and commercial
mushrooms (18), the lower yields were consistent with their
lower amounts of water-soluble components, especially soluble
sugars and sugar alcohols (7). Using the DETBA method,
methanolic extracts from medicinal mushrooms showed two
Table 1. Yieldof Methanolic Extracts fromSeveral Medicinal
aExtractedfromdriedm edicinalm ushroom s (5.00g). Eachvalueis expressed
asm ean± standarddeviation(n) 3).bMeanswithdifferentletterswithinacolum n
are significantly different (p < 0.05).
Antioxidant Properties of Medicinal Mushroom sJ. Agric. Food Chem ., Vol. 50, No. 21, 20026073
different patterns of antioxidant activities (Figure 1). At 0.6
mg/mL, Ganoderma spp., including G. lucidum, G. lucidum
antler, and G. tsugae, showed an excellent antioxidant activity
as evidenced by the relatively low percentages of lipid peroxi-
dation (2.30-6.41%). C. Versicolor showed only 58.56% of lipid
peroxidation at 0.6 mg/mL. It could be contemplated that at
concentrations >0.6 mg/mL, C. Versicolor would show a better
antioxidant activity. However, butylated hydroxyanisole (BHA)
showed only 66.1% of lipid peroxidation at 10 mg/mL.
Huang (19) found that methanolic extracts from the medicinal
mushroom Antrodia camphorata (Chang-chih) showed excellent
antioxidant activities as evidenced by 5.32-5.78% of lipid
peroxidation at 1.0 mg/mL. Methanolic extract from another
medicinal mushroom, Agaricus blazei (Brazilian mushrooms),
showed a high antioxidant activity (26.0% of lipid peroxidation)
at 1.0 mg/mL (19). Among methanolic extracts from four
specialty mushrooms at 1.2 mg/mL, only Dictyophora indusiata
(basket stinkhorn) showed an excellent antioxidant activity
(2.26% of lipid peroxidation) (18). Grifola frondosa (maitake)
showed a relatively high antioxidant activity (29.81% of lipid
peroxidation), whereas Hericium erinaceus (lion’s mane) and
Tricholoma giganteum (white matsutake) showed moderate
antioxidant activities (48.45 and 67.02% of lipid peroxidation,
Among methanolic extracts from commercial mushrooms at
1.2 mg/mL, Flammulina Velutipes (winter mushrooms), Lentinu-
la edodes (shiitake), Pleurotus cystidiosus (abalone mushrooms),
and Pleurotus ostreatus (tree oyster mushrooms) showed
moderate to high antioxidant activities (24.71-62.30% of lipid
peroxidation) (18). Mau et al. (20) reported that methanolic
extracts from ear mushrooms, including black, red, jin, snow,
and silver ears, showed low to moderate antioxidant activities
(57.7-71.5% of lipid peroxidation) at 1.0 mg/mL.
With regard to the antioxidant activities of methanolic extracts
in the DETAB method, A. camphorata, G. lucidum, G. lucidum
antler, and G. tsugae were excellent, whereas C. Versicolor was
good as compared to other medicinal, specialty, commercial,
and ear mushrooms.
Reducing Power. Reducing powers of methanolic extracts
from medicinal mushrooms increased readily along with the
increased concentrations (Figure 2). At 4 mg/mL, reducing
powers were in the order G. tsugae (2.38) ∼ G. lucidum antler
(2.28) > G. lucidum (1.62) > C. Versicolor (0.79). Similar to
antioxidant activity, C. Versicolor showed a lower reducing
power than Ganoderma spp. However, reducing powers of BHA
and R-tocopherol at 20 mM (3.6 and 8.6 mg/mL) were 0.12
and 0.13, respectively. The reducing power of medicinal
mushrooms might be due to their hydrogen-donating ability as
described by Shimada et al. (11). Accordingly, medicinal
mushrooms might contain a higher amount of reductone, which
could react with radicals to stabilize and terminate radical chain
Huang (19) reported that the methanolic extract from A.
camphorata showed an excellent reducing power of 0.96-0.97
at 10 mg/mL, whereas that from Brazilian mushrooms showed
a reducing power of 0.86 at 10 mg/mL. Among methanolic
extracts from four specialty mushrooms, basket stinkhorn
showed an excellent reducing power of 1.96 at 6 mg/mL (18).
Reducing powers of methanolic extracts from maitake, lion’s
mane, and white matsutake were 1.18, 1.01, and 0.63 at 9 mg/
mL, respectively (18). Among methanolic extracts from com-
mercial mushrooms, abalone and tree oyster mushrooms ex-
hibited excellent reducing powers of 1.00 and 1.19 at 10 mg/
mL, respectively (18). Reducing powers of methanolic extracts
from two strains of winter mushrooms were 0.52 and 0.65 at
10 mg/mL, whereas reducing powers of 0.62 and 0.85 were
observed with extracts from two strains of shiitake at 10 mg/
mL (18). Mau et al. (20) reported that methanolic extracts from
ear mushrooms excluding silver ears showed reducing powers
of 0.67-0.82 at 5 mg/mL. The reducing power of that from
silver ears was 0.32 at 5 mg/mL (20).
Apparently, with regard to reducing powers of methanolic
extracts, A. camphorata, G. lucidum, G. lucidum antler, and G.
tsugae were excellent, whereas C. Versicolor was good as
compared to other medicinal, specialty, commercial, and ear
Scavenging Effect on 1,1-Diphenyl-2-picrylhydrazyl Radi-
cal. Scavenging effects of methanolic extracts from medicinal
mushrooms on DPPH radical increased with the increased
concentrations (Figure 3). At 0.64 mg/mL, scavenging effects
were 67.6-74.4% for Ganoderma and 24.6% for C. Versicolor.
It was anticipated that scavenging effects would be excellent
for Ganoderma and higher for C. Versicolor at concentrations
>0.64 mg/mL. However, the scavenging effects of BHA and
R-tocopherol at 20 mM (3.6 and 8.6 mg/mL) were 96 and 95%,
Excellent scavenging effects (96.3-99.1 and 97.1%) were
observed with methanolic extracts from A. camphorata and
Brazilian mushrooms at 2.5 mg/mL, respectively (19). At 6.4
mg/mL, the methanolic extract from basket stinkhorn scavenged
Figure1. Antioxidantactivityofm ethanolicextractsfromseveralm edicinal
m ushroom s. Eachvalue is expressedas m ean± standarddeviation(n
Figure 2. Reducing powerofm ethanolic extracts fromseveralm edicinal
m ushroom s. Eachvalue is expressedas m ean± standarddeviation(n
6074J. Agric. Food Chem ., Vol. 50, No. 21, 2002Mau et al.
DPPH radical by 92.1%, whereas scavenging effects of metha-
nolic extracts from other specialty mushrooms were 63.3-67.8%
(18). At 6.4 mg/mL, the methanolic extract from tree oyster
mushrooms scavenged DPPH radical by 81.8%, whereas
scavenging effects of extracts from other commercial mush-
rooms were 42.9-69.9% (18). In addition, at 1 mg/mL,
methanolic extracts from black and red ear mushrooms scav-
enged DPPH radical completely (100%), whereas those from
snow and jin ear mushrooms scavenged DPPH radical by 94.5%
at 0.4 mg/mL and 95.4% at 3 mg/mL, respectively (20).
However, silver ear mushrooms were not effective in scavenging
DPPH radical (71.5% at 5 mg/mL) (20).
These results revealed that medicinal mushrooms were free
radical inhibitors or scavengers, acting possibly as primary
antioxidants. Their methanolic extracts might react with free
radicals, particularly of the peroxy radicals, which are the major
propagator of the autoxidation chain of fat, thereby terminating
the chain reaction (21-23). The antioxidant activity of natural
antioxidants has been shown to be involved in termination of
free radical reactions and reducing power (11, 24).
Scavenging Effect on Hydroxyl Radical. The scavenging
effects of methanolic extracts from G. lucidum and G. lucidum
antler were highest (51.2 and 52.6%) at 16 mg/mL, respectively
(Figure 4). G. tsugae and C. Versicolor scavenged hydroxyl
radical by 44.7 and 38.0%, respectively. However, the scaveng-
ing effect of BHA at 20 mM (3.6 mg/mL) was 23%, whereas
that of R-tocopherol at 20 mM (8.6 mg/mL) was 34%.
At 40 mg/mL, scavenging effects were 75.0 and 69.4% for
basket stinkhorn and lion’s mane and 39.6 and 47.4% for
maitake and white matsutake, respectively (18). In addition, at
40 mg/mL, the scavenging effect of methanolic extracts from
tree oyster mushrooms on hydroxyl radical was 54.3%, whereas
other commercial mushrooms scavenged hydroxyl radical by
29.2-36.6% (18). At 5 mg/mL, scavenging effects were 10.52-
14.01% for methanolic extracts from black, snow, and silver
ear musrhooms, whereas no scavenging effect was observed
with methanolic extracts from red and jin ear mushrooms (20).
Similarly, methanolic extracts from A. camphorata and Brazilian
mushrooms did not scavenge hydroxyl radical (19).
These results indicated that many mushrooms are not good
scavengers for hydroxyl radical. In addition, Shi et al. (12)
reported scavenging activity of hydroxyl radicals of caffeine
and attributed the alleged anticarcinogenic properties of caffeine
to this activity. Accordingly, it was anticipated that the moderate
to high scavenging effects of medicinal mushrooms might be
associated with some antimutagenic properties.
Chelating Effect on Ferrous Ion. Chelating effects of
methanolic extracts from medicinal mushrooms on ferrous ion
increased with the increased concentrations (Figure 5). At 2.4
mg/mL, chelating effects were in the order G. lucidum antler
(67.7%) > G. lucidum (55.5%) > G. tsugae (44.8%) > C.
Versicolor (13.2%). Evidently, C. Versicolor was not a good
ferrous chelator. However, at 20 mM (3.6 mg/mL), the chelating
effect of BHA was 36%, whereas that of R-tocopherol at 20
mM (8.6 mg/mL) was 92%. It is contemplated that a higher
chelating effect would be observed with the concentration >2.4
mg/mL. Because ferrous ions are the most effective pro-oxidants
in the food system (25), the higher chelating effects of
methanolic extracts from medicinal mushrooms would be
Methanolic extracts from A. camphorata chelated ferrous ions
by 64.4-74.5% at 5 mg/mL, whereas that from Brazilian
mushrooms showed an excellent chelating effect of 98.6% at
2.5 mg/mL (19). Yen and Wu (26) reported that the methanolic
extract of G. tsugae chelated 95.3% of ferrous ion at 600 ppm
(0.6 mg/mL). However, Yen and Wu (26) used the method of
Decker and Welch (27) to determine the chelating effect instead
of the method of Shimada et al. (11).
Table 2. Contents of Ascorbic Acid, ?-Carotene, Tocopherols, and Total Phenols of Methanolic Extracts fromSeveral Medicinal Mushroom s
aEachvalue is expressedas m ean± standarddeviation(n) 3). Means withdifferentletters withina roware significantly different(p< 0.05).bnd, notdetected.cγ,
Figure3. Scavengingeffectofm ethanolicextractsfromseveralm edicinal
m ushroom s on 1,1-diphenyl-2-picrylhydrazyl radical. Each value is
expressed as m ean± standard deviation (n) 3).
Figure4. Scavengingeffectofm ethanolicextractsfromseveralm edicinal
m ushroom s onhydroxyl free radical. Eachvalue is expressedas m ean
± standard deviation (n) 3).
Antioxidant Properties of Medicinal Mushroom s J. Agric. Food Chem ., Vol. 50, No. 21, 20026075
The methanolic extract from maitake chelated 70.3% of
ferrous ion at 6 mg/mL, whereas at 24 mg/mL, methanolic
extracts from black stinkhorn, lion’s mane, and white matsutake
chelated ferrous ion by 46.4-52.0% (18). For commercial
mushrooms including winter, abalone, and tree oyster mush-
rooms and shiitake, their methanolic extracts chelated 45.6-
81.6% of ferrous ion at 1.6 mg/mL (18). Methanolic extracts
from ear mushrooms were good chelators for ferrous ion (85.1-
96.5% at 5 mg/mL) (20). Summarily, Ganoderma mushrooms
were good chelators for ferrous ion but C. Versicolor was not.
Antioxidant Components. Total phenols were the major
naturally occurring antioxidant components found in methanolic
extracts from medicinal mushrooms (Table 2). However,
ascorbic acid and ?-carotene were not detected, whereas
tocopherols were not found in C. Versicolor. Only γ-tocopherol
was found in small amounts (0.13-1.19 mg/g) in Ganoderma
spp. However, Ganoderma mushrooms contained much higher
amounts of total phenols (47.25-55.96 mg/g) than C. Versicolor
(23.28 mg/g). Therefore, total phenols might be responsible for
the antioxidant properties studied. Phenols such as BHT and
gallate were known to be effective antioxidants (28).
As compared to the contents of total phenols in methanolic
extracts from specialty mushrooms (7.61-16.28 mg/g) (18),
commercial mushrooms (6.27-15.65 mg/g) (18), and ear
mushrooms (3.20-8.72 mg/g) (20), the highest contents of total
phenols in Ganoderma (47.25-55.96 mg/g) might be the key
components accounting for their better results found in anti-
oxidant activity, reducing power, and scavenging and chelating
Arbitrarily at 10 mg/mL, contents of total phenols in
methanolic extracts from medicinal mushrooms were in the
range of 232.8-559.6 µg/mL, much less than BHA and
R-tocopherol used at 20 mM (3.6 and 8.6 mg/mL, respectively).
Therefore, in addition to these antioxidant components, some
other components also existed and contributed in part to the
antioxidant properties of medicinal mushrooms. To study the
antioxidant mechanisms by some other potential antioxidant
components, the fractionation of the methanolic extract and
further identification are in progress.
BHA, butylated hydroxyanisole; BHT, butylated hydroxy-
toluene; DETBA, 1,3-diethyl-2-thiobarbituric acid; DMPO, 5,5-
dimethylpyrroline-N-oxide; DPPH, 1,1-diphenyl-2-picrylhydra-
zyl; EPR, electron paramagnetic resonance; TMM, tetramethyl
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Received for review January 31, 2002. Revised manuscript received
July 22, 2002. Accepted July 22, 2002. The study was supported by
National Science Council, ROC, Project NSC88-2313-B005-093.
Antioxidant Properties of Medicinal Mushroom sJ. Agric. Food Chem ., Vol. 50, No. 21, 2002 6077