INTERNATIONAL JOURNAL OF ONCOLOGY 14: 713-719, 1999
Anti-tumor effects of PC-SPES an herbal formulation in prostate cancer
R.K. T'IWARI' , J. GELIEBTER , V.P.S. GARIKAPATY', S.P.K. YEDAVELLI', S. CHEN and A. MITTELMAN
Departments of 1 Microbiology and Immunology, 2 Medicine, Division of Oncology, New York Medical College, Valhalla, NY 10595, USA
Received January 7, 1999; Accepted February 8, 1999
Abstract:
Prostate cancer is the most common cancer amongst males in developed countries. Surgical removal of the prostate effectively cures the primary disease but the metastatic disease is refractory to most forms of chemotherapy. There is a clinical need to develop novel treatment strategies that exploit the mode of action of both conventional and alternative drugs/medicinal plants. We have been investigating the antiproliferative and anti-tumor effects of an herbal preparation termed PC-SPES (patent pending, US serial number 08/697, 920) which is a refined powder of eight different medicinal plants. PC-SPES administered as a food supplement caused a dramatic decrease in prostate specific antigen levels in some prostate cancer patients with advanced disease. These preliminary clinical findings laid the foundation for a program to examine the in vitro and in vivo effects of PC-SPES, and identify the active component in this mixture so that a standardized treatment regimen can be formulated. In this communication, we report the anti-tumor effects of PC-SPES incorporated in the diet utilizing a well studied Dunning R3327 rat prostate cancer model. Dietary PC-SPES at levels of 0.05% and 0.025% did not exhibit any toxicity and no significant difference in food intake was noted at the end of six weeks. Dose dependent inhibitory effect of dietary PC-SPES was observed on both tumor incidence (P=0.01) and rate of tumor growth when tumors were induced in syngeneic Copenhagen rats by intradermal injections of MAT-LyLu cells that are known to metastasize in the lung and lymph nodes. The number of pulmonary metastases in animals on PC-SPES that showed no primary tumor growth had no metastatic lesions in the lung, however, in animals that did not respond to PC-SPES, the number of pulmonary metastases was not significantly different from the nontreated controls. The significant anti-tumor effects of PC-SPES on MAT-LyLu induced tumorigenesis and metastasis in Copenhagen rats, in general refractory to most conventional therapy, suggests a therapeutic benefit of this herbal food supplement and may be a useful adjuvant to conventional therapeutic modalities.
Correspondence to: Dr Raj K. Tiwari, Department of Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
Key words: rat model, anti-tumor effects, PC-SPES, toxicity, pulmonary metastases
Introduction
Prostate cancer accounts for over 180,000 new cases with approximately 40,000 deaths among
American men every year. Removal of the prostate is curative for the primary disease with a
substantial decline in the quality of life but metastatic prostate cancer is refractory to most
prevalent forms of radiation and chemotherapy (1,2). Furthermore, conventional treatments that
employ physical or chemical hormone deprivation leads to a more aggressive, rapidly
proliferating subset of prostate cancer cells that are hormone independent and presumably
acquire a distinct set of growth factors that mediate androgen-independent proliferation (3,4).
Specific therapy that targets the functional activity of the epidermal growth factor receptor
(EGFR) and the oncogene product HER-2/neu are in clinical evaluation but a combination
treatment schedule that can target all the subsets of prostate cancer cells is still elusive. Since
regulation of cell cycle, induction of apoptosis and steroid hormone induced signal transduction
pathways and invasion of the extracellular matrix by enhanced tumor vasculature are all involved
in the growth, maintenance and spread of prostate cancer, it is imperative that successful
treatment strategy needs to target all or several of the growth regulating pathways simultaneously.
A multi-targeted approach to prostate cancer can be promulgated in several ways. Combination
chemotherapy with drugs that target the cell cycle and angiogenesis, or radiation and
chemotherapy, or anti-hormone therapy with growth factor/signal transduction inhibitors have
shown promise but the success of each novel approach depends on its toxicity, morbidity and
nature of the prostate cancer (5-8). Since it is not always possible to examine the phenotypic
characteristics of prostate cancer cells by non-invasive procedures, the treatment options are
postponed until the appearance of overt clinical or pathological symptoms. At this point potential
treatment benefits are significantly reduced. It is therefore important to focus research attention
on the prevention of progression of benign disease utilizing a non-toxic,
multi-targeted approach.
We have been investigating the anti-tumor and antiproliferative effect Of PC SPES, a
combination of eight different medicinal plants each having a distinct clinical effect (9-11). A
dramatic drop in the prostate specific antigen (PSA) levels was observed in some advanced
prostate cancer patients. PC-SPES is a refined powder containing Ganodermab lucidium Karst.
Dendranthema morifolium Tzvel, Glycyrrhiza glabra L, Isatis indigotica, Panax pseudo-ginseng
Wall, Rabdosia rubescens, Scutellaria baicalensis Georgi, and Serenoa repens ( 11 ,12). Several
of these components exert significant biological effects for e.g. Ganoderma lucidium Karst exerts
a strong immunomodulatory effects and the immunomodulatory protein LZ-8 has been identified
(12); Baicalein a flavonoid derived from Scuttellaria baicalensis has anti-proliferative and
lipooxygnesase-inhibitory activity (13); Serenoa repens is a potent phytoestrogen and its lipid
extracts is an inhibitor of both type I and type 2 5a-reductase, the enzyme that converts
testosterone to dihydrotestosterone, the active androgen in the prostate (14); Rg 1, a saponin
derived from Panax ginseng has mitotic activity towards T cells similar to Concanavalin A
(15,16) and ginseoside-Rb2 inhibits angiogenesis in a transplantable tumor model; extracts of
Glycyrrhiza glabra has been shown to have anti-mutagenic activity (17,18). It is the combination
of several such potent medicinal plants that presumably exert a synergistic anti-proliferative
effects by acting on multiple targets simultaneously.
We examined the effect of PC-SPES in the R3327 syngeneic Copenhagen rat model using
MAT-LyLu cells. The advantage of this model is that several cell lines have been developed from
a spontaneous tumor that arose in the Copenhagen rats with varied properties. The parental G
subcell line is androgen responsive and grows slowly and is not known to metastasize. A variant
of this cell line termed as MAT-LyLu is rapidly proliferating, is androgen unresponsive and
metastasizes to the lung and lymph nodes (19). Mat-LyLu cells have a doubling time of 8 to 10 h
and have a 100% tumor take in syngeneic Copenhagen rats and are in general refractory to most
conventional forms of therapy.
In the present study we examined the effect of dietary PC-SPES at concentrations of 0.025%
and 0.05% on MATLyLu cell line induced tumorigenesis in Copenhagen rats. End-points of
investigation included tumor incidence, rate of tumor growth, pulmonary metastasis, tumor
histology and toxicity and palatability of PC-SPES containing diet. The concentration of PC-SPES have
been
computed based on the doses used in the clinic and doses that can be achieved by dietary
supplementation. Our results suggest that PC-SPES affects tumor incidence, rate of tumor
growth and pulmonary metastasis. Animals may be classified as responders and nonresponders
with complete resistance to tumors in the responders. Animals that showed no tumor were free
of metastasis suggesting that both processes of lodging at the primary site and at metastatic site
are affected by PC-SPES treatment.
Materials and Methods
Growth Of MAT-LyLu cells in vitro and in vivo. MAT-LyLu cells (a gift from John Isaacs
Laboratory, Johns Hopkins, Baltimore, MD) were grown in RPMI-1640 containing 10% fetal
bovine serum (FBS) supplemented with penicillin (50 IU/ml), streptomycin (50 ug/ml) 2 mM L-glutamine
and 2.5 mM dexamethasone. Cells were fed twice a week and were trypsinized with
0.05% trypsin-EDTA at 80 to 90% cell confluency. Since the cells are rapidly growing, care is
taken that the cells do not reach 100% confluency. Cells injected for growth in Copenhagen rats
were Generally taken from flasks that were between and 50 and 75% confluent. MATLyLu cells
were washed twice with phosphate buffered saline (PBS) and then trypsinized and suspended in
PBS at a concentration of 100,000 cells per ml. Each animal was injected with 0.1 ml of cell
suspension with an effective dose of 10,000 live MAT-LyLu cells per rat. Cell viability was
always determined by the trypan blue exclusion test and samples that exhibited less than 98%
viability were discarded. Cells were injected into the right flank of the animal which has been
shaved prior to the injection. All injections were intradermal (i.d.), using an insulin syringe. Cells
were kept at 4'C at all times prior to injections. This method of injections with MAT-LyLu, in
our experience, yields 100% tumor incidence. All experimental groups and the control animals
were injected at the same time with the same batch of cells.
Animal experiments.
Four- to five-week old Copenhagen rats were purchased from Harlan Sprague Dawley,
Indianapolis, IN, and allowed to acclimate for one week, feeding on Purina 5001 rat chow. At
the end of one week the rats were randomized into three groups of seven rats. Groups were fed
either Purina 5001 rat chow (control) or Purina 5001 rat chow containing 0.05% or 0.025%
PC-SPES. The rats were allowed to continue on the experimental diet for two weeks and their
food intake and body weight monitored. Food intake was determined by giving pre-measured
amount of food and monitoring consumption of food by weighing the remaining food every
alternate day. Body weights of the animals were measured twice a week. Average food
consumption per animal per day from each group was compared. This computation also took
into account the food wastage of each
animal in each of the groups that was in the range of 4.2-4.4 g per rat per day. Live MATLyLu
(10,000 cells/rat) were injected in all animals on day 14 after randomization into groups. All
animals were individually housed in hanging cages and had ad libitum access to food and drinking
water and were kept on twelve hour diurnal cycle. All injections and tumor measurements were
performed under light anesthesia (metofane inhalation). Experimental end point measurements
included, dietary intake, body weight gain, tumor incidence, rate of tumor growth, number
animals with pulmonary metastases and number of visible metastatic nodules per lung of the
tumor bearing animal and histopathological examination of the tumors. Tumor diameter was
measured using vernier caliper.
Dietary formulation.
PC-SPES was obtained from BotanicLab. (Brea, CA) and was incorporated into rodent chow
5001 by Purina Labs. (10). Three different concentrations 2.5 g (0.25%), 0.5 g (0.05%), 0.25 g
(0.025%) of PC-SPES per kg, were formulated. The concentration of 0.05% corresponded to
the supplementation to prostate cancer patients. In a separate experiment (not shown here) diets
containing 0.25% PC-SPES was found to be non-palatable in the case of Copenhagen rats as
50% of the animals were found to be malnourished due to refusal of food. Taste was not an issue
in the case of prostate cancer patients as they received PC-SPES in capsules. These experiments
formed the rationale for the use of 0.05% and 0.025% of PC-SPES in our experimental group.
Statistical analysis. Data was analyzed using a two-tailed Student's t-test and mean values
differing from each other at P=0.05 was considered significant.
Results
Effect of PC-SPES on the body weight of Copenhagen rats. Four to five week old Copenhagen
rats were maintained for two weeks on Purina 5001 rodent chow containing PC-SPES at 0.05%
and 0.025%, for acclimatization. Change of mean body weight per group (control, 0.05% and
0.025%) is presented in Fig. 1. The mean food intake per group in grams in the different groups
is also given in Fig. 2. It is clear that animals on PC-SPES had a decrease in the amount of food
ingested both at 0.025% and 0.05% groups as compared with the control (P=0.002) in the first
four weeks of the start of the dietary treatment. The lowered food intake is also reflected in the
body weight of the animals that is lower in the PC-SPES treated group in a dose dependent
manner. The animals on
PC-SPES were found to exhibit normal activity with no hyperactive behavior when compared
with the animals on normal diet that contained no PC-SPES. Animals on PC-SPES at 0.05%
ingested doses of PC-SPES similar to prostate cancer patients on three 333 mg capsules three
times a day. No reports of weight loss was reported in these patients (personal communication,
manuscript in preparation), on the contrary some patients had either a significant weight gain or
had maintained a steady body weight. This reflects the effect of PC-SPES on the general well
being of the prostate cancer patients on this supplement. It should be mentioned that on a dose
as high as 0.25% PC-SPES (unpublished observations and data not shown), the animals were
malnourished as they refused the supplemented food. It is presumed that such a high
concentration of PC-SPES interfered with the palatability of the chow to Copenhagen rats. The
fact that 0.05% dose was well tolerated by these animals with no significant overt toxicities as
determined by hair loss, loss of appetite, lack of locomotion suggests that supplementation of
PC-SPES at this dose assuming similar metabolism in rats and humans should not produce any
toxicities in humans. In fact supplementation Of PC-SPES at this dose in human patients is well
tolerated by prostate cancer patients.
Effect Of PC-SPES on tumor incidence in Copenhagen rats. Results presented in Fig. 3
shows the dose dependent effect of PC-SPES on tumor incidence in Copenhagen rats, when
tumor was induced by i.d. injections of 10,000 live MAT-LyLu cells. PC-SPES incorporated in
the diet at 0.025% resulted in a 20% decrease in palpable tumors in animals, whereas, when the
dose Of PC-SPES in the diet is increased to 0.05% tumor incidence was decreased by more
than 40% (P=0.05). Similar observations were obtained earlier in another experiment with five
animals per group. Thus the observations presented here are reproducible and seem to reflect the
biological effect of ingested PC-SPES. Dose dependent effect of PC-SPES on tumor incidence
suggests that there appears to be responders and non-responders even in inbred strain of
experimental animals. Copenhagen rats on PC-SPES diet with no evidence of primary tumor
showed no pulmonary metastasis. All the animals in the control
showed primary tumor as well as pulmonary metastases. The effect on tumor induction as
observed in reduction of tumor incidence at both 0.05% and 0.025% PC-SPES together with
the observation that animals that did not have primary tumor lacked pulmonary metastases has
significant implication in the preventive use of this herbal supplement provided long term use of
PC-SPES does not have in vivo toxicity or any side effects. It is also clear from our experiments
that doses below 0.025% PC-SPES may not have any significant impact on tumor incidence and
hence pulmonary metastasis suggesting an optimal threshold cellular concentration prior to
manifestation of its biological effect.
Effect of PC-SPES on the rate of tumor growth and pulmonary metastases in
Copenhagen rats. Dose dependent decrease in the tumor burden was noted in animals that
were administered PC-SPES. The reduction was noted three weeks after tumor injection with
increasing difference in rate of tumor growth inhibition. The mean values were lower than the
control as much as 50% [compare mean values of 0.05% treated animals 1.35 to 2.98 in control
(Fig. 4)]. A wide range in the tumor sizes was observed in the experimentally treated animals and
as such the values did not attain statistical significance. Nevertheless the wide difference in the
mean values together with the observation that some animals were devoid of tumors suggests a
differential action of this herb and in animals which are responders or partial responders an
antitumor effect is observed. Animals that received 0.05% PCSPES showed a plateau in the
growth rate, however animals that were scored positive for the primary tumor also showed lung
metastasis. Statistically significant decrease (P=0.05) in pulmonary metastasis was observed in
the PC-SPES treated (0.05%) when compared with the untreated controls (Fig. 5). It should be
noted that 20% of the animals in 0.025% and 40% of the animals in the 0.05% PC-SPES
treated animals did not exhibit any lung metastasis. Similar to the effect of PC-SPES on tumor
growth the number of macroscopically visible lung metastases showed considerable variation,
however, the mean values in the PC-SPES treated control were found to be statistically different
from the control group of animals.
Discussion.
Effect of PC-SPES on the growth of Copenhagen rats. PC-SPES at doses of 500 and 250
parts per million was well tolerated by Copenhagen rats with no overt toxicity symptoms. A
difference in the mean amount of food consumed can be attributed to peripheral rodent
identifiable factors such as taste, odor or texture. These results are contrary to results obtained
with PC-SPES supplementation in a capsular form in prostate cancer patients where either a
weight gain or stabilization but no weight loss was observed. Since palatability and taste was not
a factor in the human
population, it is presumed that taste was the major determinant in lowered food intake.
Anti-tumor effects of PC-SPES. Our studies using Copenhagen rats and the transplantable,
rapidly proliferating, highly metastatic cell line, MAT-LyLu indicates that dietary supplementation
with the Chinese herbal preparation of PC-SPES can modulate tumor incidence, rate of tumor
growth and pulmonary metastases. These results are of special significance in the MAT-LyLu
model as growth of these cells are in general refractory to most forms of treatment. Decrease in
tumor incidence in a dose dependent manner suggests that some animals respond to the anti-tumor effect
of PC-SPES better than others and that even in genetically identical inbred strains of
rats we may be able to identify PC-SPES responders and non-responders. This is reminiscent of
the human experience with PC-SPES where some patients showed dramatic response or were
partial responders, while others were completely refractory (Mittelman A, et al, manuscript in
preparation). Although the precise mechanism for such an action is elusive, one can speculate
that since PC-SPES is a mixture of several different medicinal plants, each with its target of
action, induction of a synergistic response may be host dependent (11). While published data on
the biological effects of PC-SPES suggests that specific ethanol extracts of PC-SPES induces
apoptosis and cell cycle deregulation predominantly a prolongation of the G1 phase of the cell
cycle, immunological modulation by induction of tumor specific cytolytic T cells by specific
component(s) Of PC-SPES in its in vivo effect cannot be ruled out (11).
The anti-tumor effect of a non-toxic dietary supplement of combination of medicinal plants
suggests the relevance of the use of combination therapy that is capable of utilizing multiple
targets. These multiple targets consist of biochemical intermediaries that mediate the cell cycle
transition by ethanol extracts of PC-SPES (11). Components of PC-SPES can target specific
biochemical targets e.g. Glycerrhiza can reverse mutations (20), Serenoa repens, a
phytoestrogen lowers estrogen levels and affects androgen receptor binding with its ligand (
14,21,22), Scuttelaria baicalensis that contains baicalin inhibits
lipooxygenase and DNA topoisomerase activity (23,24), extracts of Ganoderma lucidum have
potent immunomodulatory effects (12), Panax ginseng, probably the most studied herb, has anti-carcinogenic
effects on spontaneous and carcinogen induced tumor model systems as well as can
affect tumor metastases (11,25). Thus, while most of the active components individually have
anti-tumor effects, several different herbs in a mixture in the Chinese and Japanese traditional
medicine has been found to be more efficacious. The Generation and success of popular mixtures
such as 'sho-saiko-to' and 'juzentaihoto' for hepatocellular diseases and enhancement of drug
induced anti -neoplastic effects in China and Japan relates to the effectiveness of combination
therapy. Each individual component, though potent in their individual effects cannot compare with
the effect of the combination preparation (25,26). These anecdotal observations support the
hypothesis that preparation that contain mixtures of individually potent drugs have enhanced
efficacies that may be related to either synergism of the individual components or the
simultaneous hit on multiple cellular and biochemical targets that not only eliminates existing
malignant cells but can also prevent the clonal expansion of neoplasms and their further
differentiation and thus prevention of secondary metastasis. A recent report f the use of PC-SPES examined
the estrogenic effect of PCSPES in an animal model and in eight patients (27).
While the substantial decrease in prostate specific antigen correlated with our observations, the
doses used were 'too high' and thus the validity of the estrogenic effect was questioned.
Standardized treatment using PC-SPES. The long-term goal of our studies is to identify
the
active component(s) of herbal preparations that have shown anti-tumor effects. PC-SPES is one
such preparation that has similarities with other Chinese and Japanese preparations from
medicinal plants but is unique in other respects. Evaluation of the water soluble and ethanol
extracts of PC-SPES in in vitro and in vivo studies, and separation of the active components
using high performance liquid chromatography (HPLC) and examination of the cellular and
molecular effects will help development of a standardized drug-like treatment procedures. These
studies will help alternative medicinal plant based therapy to enter into the field of molecular
medicine. Furthermore, identification of the cellular and molecular targets of the active
component of PC-SPES will provide an intermediate biomarker that can presumably evaluate
the efficacy of the treatment and or compliance to a treatment schedule.
Acknowledgements
These studies were supported by grants from AICR (94B66), USARMY (DAMD 17-98-1-8534) and Granoff Foundation
to R.K.T., Zita Spiss Foundation to R.K.T. and J.G., AICR
(97AO72) to J.G. and Zalmin A. Arlin Cancer Fund to A.M.
References
1. Landis SH, Murray T, Bolden S, Wingo PA: Cancer statistics. Cancer J Clin 48: 6-29, 1998.
2. Parker SL, Tong T, Bolden S and Wingo PA: Cancer statistics. Cancer J Clin 46: 5-27, 1996.
3. Scher SL: Prostate cancer: improving the therapeutic index. Semin Oncol 21: 688-693, 1994.
4. Visakorpi T, Hyytinen E, Koivisto P, et al: In vivo amplificat;on of the androgen receptor -ene and
progression of human prostate cancer. Nat Genet 9: 401-407, 1995.
5. Scher HI, Zhang ZF and Kelly WK: Hormone and Anti hormone withdrawal therapy: implication for
management of androaen independent prostate cancer. Urology 47: 6i-69, 1996.
6. Steiner MS: Role of peptide -rowth factors in the prostate: a review. Urology 42: 99-110, 1993.
7. Peehl DM, Wong ST and Stamey TA: Cytostatic effects of suramin on prostate cancer cells cultured
from
primary tumors J Urol 145: 624-630, 1991.
8. Eisenberger MA, Sinibaidi VJ, Reyno LM, et al: Phase 1 clinical evaluation of a pharmacologically
guided
regimen of suramin in patients with hormone refractory prostate cancer. I Clin Oncol 13: 2174-2186,
1995
9. Fan S and WaniZ X: Composition of herbal extracts SPES, United States patent number 5,417979, issued
May 1995
10. Fan S and Wang X: Herbal composition for treating prostate cancer. PC-SPES, pending United States
patent number 08/697920.
11. Halicke DH, Ardel B, Juan G, Mittelman A, Chen S, Traganos F and Darzynkiewicz Z: Apoptosis and
cell
cycle effects induced by extracts of the Chinese herbal preparations PCSPES. Int J Oncol 11: 437-448,
1997.
12. Murasu.-i A, Taneka S, Komiyama N, lwata N, Kino K, Tsumo H and Sakuna S: Molecular cloning of a
CDNA and a gene encodino- an immunomodulatory protein ling zhi-8 from a fungus Ganodenna lucidum. J
Biol Chem 266: 2486-2493, 1991.
13. Hung HL, Wang HL and Hseih LM: Antiproliferative effect of baicalein, a flavonoid from a Chinese
herb
on vascular smooth muscle. Eur J Pharmacol 251:
91-93, 1994.
14. lehle C, Delos S, Guitou 0, Tate R, Raynaud JP and Martin PM: Human prostatic steroid 5a reductase
isoforms - a comparative study of selective inhibitors. J Steroid Biochem Mol Biol 54: 273-279, 1995.
15. Liu J, Wang S, Liu H and Yang LNG: Stimulatory effect of saponin from Paiiax ginseng on immune
function of lymphocytes in the elderly. Mech Ageing Dev 83: 43-53, 1995. .
16. Mizuno M, Yamada J, Teri H, Kozukue N, Lee YS and Tsuchida H: Differences in immunoblotting effects
between wild and cultured Panax ginseng. Biochem Beefiest Res Common 200: 1672-1678, 1994.
17. Stencil DM and Clarke CH: Specificity of antimutagens against chemical mutagens in microbial systems.
Basic Life Sci 52: 457-460,1990.
18. Zani F, Cuzzoni MT, Daglia M, Benvenuti S, Vampa G and Mazza P: Inhibition of mutagenicity in
Sabnonella typhimuriwn by Glycrrhiza galbra extract glycrrhizinic and 18a and 188 alycerrhetinic acids.
Planta
Med-5-9: 502-507, 1993.
19. Isaacs JT, Isaacs WB, Feitz WFJ and Scheres J: Establishment and characterization of seven Dunning
rat
prostate cancer cell lines and their use in developing methods for predicting metastatic abilities of
prostate
cancer. Prostate 9: 261-281, 1986.
20. Chen X and Han R: Effect of glycyrrhetinic acid on DNA damage and unscheduled DNA synthesis
induced by benzo(cL)pyrene. Chin Med Sci J 10: 16-19, 1995.
21. Delos S, Carsol JL,.Ghazarossian E, Raynaud J and Martin PM: Testosterone metabolism in primary
cultures of human prostate epithelial cells and fibroblasts. J Steroid Biochem Mol Biol 55: 375-383,
1995.
22. Carilla E, Briley M, Fauran F, Sultan C and Duvillius C: Binding of permixon, a new treatment for
prostatic
benign hyperplasia to the cytostatic androgen receptor in the rat prostate. J Steroid Biochem 20: 521-523,
1984.
23. Austin CA, Patel S, Ono K, Nakane H and Fisher LM: Site specific DNA cleavage by mammalian DNA
topoisomerase 11 induced by novel flavone and catechin derivatives. Biochem J 282: 883-889, 1992.
24. Matsuzaki Y, Kuokawa N, Terai S, Matsumura Y, Kobayashi N and Okita K: Cell
death induced by baicalein in human hepatocellular carcinoma cell lines. Jpn J Cancer Res 87: 170-177,
1996.
25. Huan KC: The Pharmacology of Chinese Herbs - CRC Press,1993.
26. Yano H, Mizoguchi A, Fukuda K, Haramaki M, Ocasawa S, Momosaki S and Kojiro M: The herbal
medicine sho-saiko-to inhibits proliferation of cancer cell lines by inducing apoptosis and arrest at
the GO/G I
phase. Cancer Res 54: 448-454, 1994.
27. Di Paola RS, Zhang H, Lambert GH, Meeker R, et al: Clinical and biologic activity of an estrogenic
herbal
combination (PC-SPES) in prostate cancer. N Engi J Med 339: 785-791, 1998.
|