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Biol. Pharm. Bull. 26(2) 271—273 (2003)
Anti-tumor Promoting Effect of Glycosides from Prunus persica Seeds
Toshiyuki FUKUDA,a Hideyuki ITO,a Teruo MUKAINAKA,b Harukuni TOKUDA,b Hoyoku NISHINO,b and
Takashi YOSHIDA*,a
a Faculty of Pharmaceutical Sciences, Okayama University; Tsushima, Okayama 700–8530, Japan: bKyoto Prefectural
University of Medicine; Kamigyo-ku, Kyoto 602–0841, Japan. Received August 26, 2002; accepted November 15, 2002
Four minor components, along with the major cyanogenic glycosides, amygdalin and prunasin, were isolated
from Prunus persica seeds (Persicae Semen; Tounin), and characterized as mandelic acid glycosides ( b-gentiobioside
and b-D-glucoside) and benzyl alcohol glycosides ( b-gentiobioside and b-D-glucoside). The anti-tumor
promoting activity of these compounds was examined in both in vitro and in vivo assays. All of the compounds
significantly inhibited the Epstein-Barr virus early antigen activation induced by tumor promoter. In addition,
they produced a delay of two-stage carcinogenesis on mouse skin that was comparable in potency to (2)-epigallocatechin
gallate from green tea. Structure–activity relationships indicated that a substituent at the benzylic position
with glycosidic linkage affected the in vitro and in vivo activities with an order of enhancing potency,
CN,COOH,H.
Key words: Prunus persica seed; cancer chemoprevention; amygdalin-related glycoside; benzyl b-gentiobioside; EBV-EA induction;
mouse skin two-stage carcinogenesis
Prunus persica (L.) BATSCH (Rosaceae) seeds are well
known as a traditional medicine (Persicae Semen; Tounin,
Taoren in Chinese) in Japan, China, and other Asian countries.
They are frequently used as an ingredient in a variety of
Kampo (Chinese medicine) prescriptions, particularly those
used to treat women’s diseases. The chemical constituents of
the herb include the cyanogenic glycosides, amygdalin (1)
and prunasin (2) as major components,1) along with glycerides,
2,3) sterols,4) and emulsin.5) Amygdalin is also abundant
in the seeds of bitter almond and apricots of the Prunus
genus, and other rosaceous plants.6) Amygdalin (1), sometimes
referred to as vitamin B17, and nitriloside was previously
thought to be synonymous with laetrile, a drug used to
treat cancer.7) However, studies now show that laetrile, an
acronym for laevorotatory nitriloside, is ineffective as a cancer
treatment, and is structurally different from amygdalin.
Thus, the antitumor effect of 1 remains ambiguous. In our
phytochemical investigation of Persicae Semen, we isolated
and characterized four minor components that were structurally
related to 1 and 2, and examined their function and
antitumor properties. Here we report the inhibitory effect of
purified constituents from Persicae Semen on the induction
of Epstein-Barr virus early antigen (EBV-EA) in Raji cells,9)
a convenient in vitro assay for assessing anti-tumor promoting
activity. In vivo anti-tumor promoting activity was also
evaluated using two-stage mouse skin carcinogenesis test.
MATERIALS AND METHODS
Isolation and Characterization of Minor Constituents
Persicae Semen (500 g), purchased from Uchida Wakanyaku
Co., Ltd., Tokyo, was homogenized in 70% aqueous ethanol
(5 l). The concentrated homogenate was extracted with nhexane
(3 l), ethyl acetate (3 l) and 1-butanol (3 l), successively.
The 1-butanol extract (5.0 g) was chromatographed
over a porous polymer gel, Diaion HP-20 (Mitsubishi Chemical
Co.) with H2O, 10% ethyl alcohol (EtOH), 20% EtOH
and EtOH. Eluates with 10% EtOH (0.98 g) and 20% EtOH
(0.48 g) were used for preparative HPLC [Waters m-Bondasphere
C-18 (5 m) 100 Å, i.d. 193150 mm; CH3CN–H2O
(13 : 87, 10 : 90 or 5 : 95) or MeOH–H2O (15 : 85)], and six
constituents, 1 (671.8 mg), 2 (173.7 mg), 3 (32.5 mg), 4 (37.0
mg), 5 (74.4 mg), and 6 (13.8 mg), were isolated. Four minor
constituents (3 to 6) were identified by comparison of their
physicochemical data with those reported in the literature
as amygdalinic acid (mandelic acid b-gentiobioside) (3),8)
[high resolution (HR)-MS: m/z 499.1451 (M1Na)1: Calcd
for C20H28O131Na, 499.1428, [ a]D 2108° (c50.6, MeOH)],
mandelic acid b-D-glucopyranoside (4)10) [HR-MS: m/z
337.0899 (M1Na)1: Calcd for C14H18O81Na, 337.0899,
[ a]D 283° (c50.5, C5H5N)], benzyl b-gentiobioside (5)11)
[HR-MS: m/z 450.1932 (M1NH4)1: Calcd for C19H28O111
NH4, 450.1975, [ a]D 258.3° (c51.0, MeOH)], and benzyl
b-D-glucopyranoside (6)12) [HR-MS: m/z 288.1475 (M1
NH4)1: Calcd for C13H18O61NH4, 288.1447. [ a]D 256° (c5
0.5, MeOH)], respectively.
Assay for Inhibition of EBV-EA Activation EBV-EApositive
serum from a patient with nasopharyngeal carcinoma
(NPC) was a gift from the Department of Biochemistry,
Oita Medical University. EBV genome-carrying lymphoblastoid
cells (Raji cells derived from Burkitt’s lymphoma)
were cultured in 10% fetal bovine serum (FBS) in
RPMI-1640 medium (Nissui). Spontaneous EBV-EA activation
in our Raji cell subline was less than 0.1%. Inhibition of
EBV-EA activation was assayed using Raji cells (virus nonproducer
type) as described previously.9,12) Indicator cells
(Raji, 13106 cells/ml) were incubated at 37 °C for 48 in 1ml
of medium containing 0.5 M n-butyric acid [8 ml, 4 mmol (coinducer)]
and 12-O-tetradecanoylphorbol 13-acetate (TPA)
[32 pmol520 ng in dimethylsulfoxide (DMSO), 2 ml] as an
inducer, with or without various amounts of test compounds
in 5 ml DMSO. Smears were made from the cell suspension,
and activated cells that were stained by EBV-EA-positive
serum from the NPC patient were detected by an indirect immunofluorescence
technique.14) At least 500 cells were
counted in each assay, and the number of stained (positive)
cells was recorded. Triplicate assays were performed for each
compound. The average EBV-EA induction of the test compounds
was expressed as the relative ratio to the control experiment
(100%), which was carried out with only n-butyric
acid (4 mmol) plus TPA (32 pmol). EBV-EA induction was
typically around 35%. The viability of treated Raji cells was
assayed by Trypan Blue staining.
Assay for Anti-tumor Promoting Activity in Two-Stage
Mouse Skin Carcinogenesis Assays were performed according
to a previously described method.15) Specific
pathogen-free female ICR mice (six weeks old) were obtained
from Japan SLC Inc., Shizuoka, Japan. The animals
were housed, five per polycarbonate cage, in a temperaturecontrolled
room at 2462 °C and given food and water ad libitum
throughout the experiment. Animals were divided into
three experimental groups containing 15 mice each. The
back of each mouse was shaved with surgical clippers, and
the mice were treated topically with 7,12-dimethylbenz[a]anthracene
(DMBA) (100 mg, 390 nmol) in acetone (0.1 ml) as
an initiating treatment. One week after initiation, papilloma
formation was promoted twice weekly by applying 12-Otetradecanoylphorbol-
13-acetate (TPA) (1 mg, 1.7 nmol) in
acetone (0.1 ml) to the skin. One hour before each treatment,
mice were treated with the samples (85 nmol) in acetone
(0.1 ml). Papilloma incidence was examined weekly over a
period of 20 weeks.
RESULTS AND DISCUSSION
Besides the major cyanogenetic glycosides 1 and 2, we
found four minor glycosides in Persicae Semen, characterized
as amygdalinic acid (3), mandelic acid b-D-glucopyranoside
(4), benzyl b-gentiobioside (5) and benzyl b-D-glucopyranoside
(6). Of these compounds, 6 has also been
found in P. mume fruits, and was reported to have hypotensive
diuretic properties.16) In addition, compound 3 was reported
to have anticancer property upon oral administration
to mice having inoculated tumor cells (AC755).17) On the
other hand, Okuyama et al. reported that Kampo prescriptions
such as Toukaku-johki-to (Taone-chengqi Tang) including
Persicae Semen as an ingredient, which are employed
for an Oketsu syndrome (stagnation of blood circulations),
showed a relatively strong anti-tumor promoting effect.18)
These findings may imply that Persicae semen contributes to
the effect. As a part of investigation to develop the function
of the Persicae Semen constituents, we examined their suppressive
effects on the tumor-promotion stage during multistage
chemical carcinogenesis.
The inhibitory TPA-induced EBV-EA activation test in
Raji cells was examined first for 1—6, and the results are
shown in Table 1. Amygdalinic acid (3), benzyl b-gentiobioside
(5) and benzyl b-D-glucopyranoside (6) produced remarkable
inhibition (65—80%) of EBV-EA activation at a
concentration of 500 mol ratio/TPA, without exhibiting cytotoxicity.
Their potencies were either comparable to, or much
stronger than the positive control, (2)-epigallocatechin gallate
(EGCG), which is a well known anti-tumor promoting
polyphenol from green tea.19) In both the gentiobiosides and
the glucosides, the inhibitory effect was dependent on a substitutent
at the benzylic position of the aglycone with an
order of potency, CN,COOH,H. Gentiobiosides showed
stronger activity than the glucoside series with the same substituent,
i.e., 1.2, 3.4, and 5.6.
The isolated compounds were then subjected to an in vivo
two-stage mouse skin carcinogenesis assay using DMBA as
an initiator and TPA as a promoter. The results are shown in
Fig. 1. The control animals exhibited a 100% papilloma incidence
10 weeks after initiation. However, treatment with the
tested compounds (85 nmol), along with initiator and promoter,
reduced the percentage of tumor-bearing mice by between
13.3—33.3% after 10 weeks (Fig. 1A). Structure–activity
relationships in this assay were similar to those in the
in vitro EBV-EA activation assay, although the in vivo test for
6 could not be examined owing to insufficient amounts available.
Thus, benzyl b-gentiobioside (5) had the most potent
activity, reducing the incidence to 86.6% over 20 weeks. In
the treated animals, the average number of papillomas per
mouse was reduced to about 44.0% to 59.3% relative to the
control group by week 20 (Fig. 1B). It is noteworthy that the
potency of 5 and 3 was almost comparable to that of EGCG
at the same concentration (85 nmol) (Fig. 1).
Chemoprevention is an efficient strategy for cancer prevention,
and extensive efforts have been made in recent years
to find natural and synthetic products that prevent the tumorpromoting
stage, which is a long and reversible process during
multi-stage carcinogenesis in humans. In the present
study, some structurally simple glycosides were found to
have significant anti-tumor promoting activity. It should be
noted that amygdalinic acid (3) might be effective agent not
only for inhibition of the growth of tumors (AC755) inoculated
in mice7) but also for chemoprevention of cancer. These
compounds, as well as the Persicae Semen extract, would be
a promising source of possible cancer chemopreventive
agents, and valuable to be further studied.
Acknowledgement This work was supported by grants
from the Ministry of Education, Science, Sports and Culture
of Japan and also in part by a grant from the National Cancer
Institute (CA 17625).
Prijava
FAQ
Pretraživač
), suncokret, u susam, u kombinaciju malteksa koji je bogat sa B vitamine skoro sve vrste.(LAN u najvecu kolicinu a vidim da je on nabrojan u produkte koje sadrze B17). Dalje pila sam Zelenu Magmu koja ovde se navodi da je bogata vitamina B17,neko je to naveo u postova mada na deklaraciju zelene magme ne pishe nigde da ima B 17, a sudeci po raspravije mozda i ne sme da stoji da ima?!?! 
