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β-carboline alkaloid-enriched extract from the amazonian rain forest tree pao pereira suppresses prostate cancer cells



Bark extracts from the Amazonian rain forest tree Geissospermum vellosii (pao pereira), enriched in alpha-carboline alkaloids have significant anticancer activities in certain preclinical models. Because of the predominance of prostate cancer as a cause of cancer-related morbidity and mortality for men of Western countries, we preclinically tested the in vitro and in vivo effects of a pao pereira extract against a prototypical human prostate cancer cell line, LNCaP. When added to cultured LNCaP cells, pao pereira extract significantly suppressed cell growth in a dose-dependent fashion and induced apoptosis. Immunodeficient mice heterotopically xenografted with LNCaP cells were gavaged daily with pao pereira extract or vehicle control over 6 weeks. Tumor growth was suppressed by up to 80% in some groups compared with tumors in vehicle-treated mice. However, we observed a striking U-shaped dose-response curve in which the highest dose tested (50 mg/kg/d) was much less effective in inducing tumor cell apoptosis and in reducing tumor cell proliferation and xenograft growth compared with lower doses (10 or 20 mg/kg/d). Although this study supports the idea that a pao pereira bark extract has activity against human prostate cancer, our in vivo results suggest that its potential effectiveness in prostate cancer treatment may be limited to a narrow dose range.
Journal of the Society for Integrative Oncology, Vol 7, No 2 (Spring), 2009: pp 59–65 59
© 2009 BC Decker Inc
bark extract is enriched for alkaloids of the B-carboline fam-
ily. These types of alkaloids have been shown to be cytotoxic
for cancer cells, and their mechanism of action may involve
the targeting of cyclin-dependent kinases (CDKs).3–5 None
of the previous studies on pao pereira bark extracts involved
human prostate cancer cell lines, so here we report our pre-
clinical studies to test whether a standardized extract of pao
pereira bark might affect the in vitro or in vivo growth of a
prototypic human prostate cancer cell line, LNCaP.
Our focus on prostate cancer derives from the predomi-
nance of this cancer as a health concern for men in Western
countries. Prostate cancer is the most frequently diagnosed
malignancy in males and a leading cause of cancer deaths in
men.6 Given the relatively high frequency with which pros-
tate cancer occurs, prevention offers the most likely means
to reduce the health risk to men posed by the disease. If pao
pereira bark extract has tumor-suppressing activity for pros-
tate cancer without overt toxicity, one can consider the pos-
sibility that it might be used as a preventive agent as a dietary
supplement. Moreover, there is a great need for better thera-
peutic agents to treat advanced (metastatic) prostate cancer.
Although hormone therapy is the standard for men with this
stage of disease, it is mainly a palliative treatment that loses
effectiveness over time. Once prostate cancer progresses to
Numerous chemotherapeutic agents used in the
treatment of cancer were originally derived from
plants. Such agents include the vinka alkaloids, extracted
from the Madagascar periwinkle; taxanes, extracted from
Pacific yew tree bark; etoposide, extracted from the may-
apple plant; and irinotecan and topotecan, extracted from
Camptotheca acuminata. In a similar manner, Beljanski and
Crochet proposed that extracts of the bark of an Amazonian
rain forest tree, Geissospermum vellosii Allemão (familiarly
known as pao pereira), used medicinally by South American
Indian tribes, might have activity against human tumors.1–3
In preliminary investigations, Beljanski and Crochet demon-
strated that pao pereira bark extract suppressed the in vitro
growth of several human cancer cell lines, including ones
derived from melanoma and glioblastoma.1–3 Pao pereira
B-Carboline Alkaloid–Enriched Extract from the
Amazonian Rain Forest Tree Pao Pereira Suppresses
Prostate Cancer Cells
Debra L. Bemis, PhD, Jillian L. Capodice, LAc, MS, Manisha Desai, PhD, Aaron E. Katz, MD, Ralph Buttyan, PhD
Bark extracts from the Amazonian rain forest tree Geissospermum vellosii (pao pereira), enriched in ]-carboline alkaloids have signifi-
cant anticancer activities in certain preclinical models. Because of the predominance of prostate cancer as a cause of cancer-related
morbidity and mortality for men of Western countries, we preclinically tested the in vitro and in vivo effects of a pao pereira extract
against a prototypical human prostate cancer cell line, LNCaP. When added to cultured LNCaP cells, pao pereira extract significantly
suppressed cell growth in a dose-dependent fashion and induced apoptosis. Immunodeficient mice heterotopically xenografted with
LNCaP cells were gavaged daily with pao pereira extract or vehicle control over 6 weeks. Tumor growth was suppressed by up to
80% in some groups compared with tumors in vehicle-treated mice. However, we observed a striking U-shaped dose-response curve
in which the highest dose tested (50 mg/kg/d) was much less effective in inducing tumor cell apoptosis and in reducing tumor cell
proliferation and xenograft growth compared with lower doses (10 or 20 mg/kg/d). Although this study supports the idea that a pao
pereira bark extract has activity against human prostate cancer, our in vivo results suggest that its potential effectiveness in prostate
cancer treatment may be limited to a narrow dose range.
pao pereira, preclinical, prostate cancerKey words:
Debra L. Bemis, Jillian L. Capodice, and Aaron E. Katz: Department of
Urology, College of Physicians and Surgeons, Columbia University Medical
Center, New York, NY; Manisha Desai: Department of Biostatistics, Mailman
School of Public Health, Columbia University Medical Center, New York, NY;
Ralph Buttyan: The Ordway Research Institute, Albany, NY.
Debra L. Bemis, PhD, Reprint requests: Ludwig Institute for Cancer Research,
605 Third Avenue, New York, NY 10158; e-mail:
DOI 10.2310/7200.2009.0009
059-065_JSIO_2009_0009.indd 59 3/29/09 1:42:55 AM
60 Journal of the Society for Integrative Oncology, Spring 2009, Volume 7, Number 2
condition). WST-1 labeling solution (WST-1 Cell Proliferation
Assay Kit, Roche Diagnostics, Indianapolis, IN) was added
at 24, 48, or 72 hours following the addition of the extract.
Three hours later, formazan product was detected at 420 nm
in a spectrophotometric plate reader (Tecan, Männedorf,
Switzerland). Each experiment was repeated in triplicate.
Cell Cycle Analysis
Cultured LNCaP prostate cancer cells were exposed to
various concentrations of pao pereira extract for 24 hours.
Adherent cells were trypsinized and pooled with the cells
in suspension, centrifuged, and washed twice with ice-
cold phosphate-buffered saline. A fraction of washed cells
was stained with trypan blue and counted. The cells were
adjusted to 1 million cells per milliliter and fixed in a 2:1
ratio (vol/vol) of chilled ethanol overnight before staining
with propidium iodide in the presence of ribonuclease. Cell
cycle distribution was analyzed on a Becton Dickinson Flow
Cytometer (BD Biosciences, San Jose, CA), and 10,000 cells
were analyzed for each experimental condition. Data analy-
sis was performed using the CellQuest cell cycle analysis
software (BD Biosciences).
Generation of Tumor Xenografts and Oral Gavage with
Pao Pereira Extract
LNCaP tumor xenografts were generated in 4- to 5-week-old
male athymic nude mice (nu/nu; Harlan Inc., Indianapolis,
IN). Mice were randomized into four groups of eight each.
Following 3-day acclimation, freshly harvested LNCaP cells
were xenografted subcutaneously over the right flank of the
mice as previously described.8 Oral gavage (0.5 mL) was ini-
tiated 48 hours following xenografting, as follows: (1) vehicle
control (0.12% DMSO); (2) 10 mg/kg pao pereira extract;
(3) 20 mg/kg pao pereira extract; or (4) 50 mg/kg pao pereira
extract. Gavage was performed 6 days per week at the same
time per day for 6 weeks. Tumor volumes were calculated
one to two times per week using caliper measurements
of length, width, and depth [volume = (Pxh) × (h2 + 3a2)/6,
a = (L + W)/4].9 Mice were injected subcutaneously with a
10 mM solution of bromodeoxyuridine (BrdU) at a dose of
15 ML/g body weight 4.5 hours prior to euthanasia. Tumors
were then removed, fixed for 24 hours in 10% formalin solu-
tion, paraffin embedded, and sectioned onto glass slides for
immunohistochemical analyses.
Immunohistochemical Analysis of Tumor Xenografts
Tumor sections were stained for BrdU incorporation using
the In Situ Cell Proliferation Kit II POD (Roche Applied
the hormone-refractory stage, few chemotherapeutic agents
are known to affect patient survival. Recently, it was shown
that a combination of docetaxel, a paclitaxel (Taxol) deriva-
tive, with estramustine does offer some therapeutic advan-
tage for hormone-refractory prostate cancer patients, but the
survival gained is limited to a few months at most.7 Therefore,
there is good reason to consider whether natural agents
that act by mechanisms different from the chemotherapeu-
tics now in use might help prostate cancer patients. In this
regard, we had previously used LNCaP cells to identify the
anti–prostate cancer activity of a B-carboline alkaloid–rich
extract of another medicinal plant, Rauwolfia vomitoria.8 In
contrast to our findings with Rauwolfia extracts, however, we
report herein results showing a striking discrepancy involv-
ing the effectiveness of escalated doses of pao pereira extract
for in vivo tumor growth inhibition. Our results suggest that
the pao pereira extract might differ fundamentally from the
B-carboline-rich extracts of other medicinal plants.
Methods and Materials
Pao Pereira Extracts
All experiments were conducted with a proprietary extract of
pao pereira bark enriched in B-carboline alkaloids (Natural
Source International, Ltd., New York, NY). A single batch
of the extract, which was determined by high-performance
liquid chromatrography analysis to contain 54% B-carboline
alkaloids, was used. The pao pereira extract was dissolved in
6% dimethyl sulfoxide (DMSO) in water and was filtered
through a 0.2 µm membrane. The final concentration of
DMSO following dilution in cell culture was 0.12%. A stock
solution of 6% DMSO was used for vehicle controls.
Cell Culture
The androgen-sensitive human prostate cancer LNCaP cells
were obtained from the American Type Culture Collection
(Manassas, VA) and were grown in RPMI-1640 medium
with L-glutamine (GIBCO Invitrogen Corp., Carlsbad, CA),
supplemented with 10% fetal bovine serum and 100 mg/L
erythromycin (Sigma-Aldrich, St. Louis, MO). The cells were
maintained at 37°C in a humidified atmosphere of 95% air
and 5% CO2.
Cell Growth Assays
LNCaP cells were seeded in 96-well plates at a density of
5,000 cells per well in a final volume of 100 µL. Twenty-four
hours later, the medium was replaced with 100 µL of fresh
medium containing different concentrations of pao pereira
extract (100, 250, and 500 µg/mL) or vehicle (n = 8 for each
059-065_JSIO_2009_0009.indd 60 3/29/09 1:42:55 AM
Bemis et al, Pao Pereira Suppresses Prostate Cancer 61
Sciences, Indianapolis, IN) and were counterstained with
methyl green. TUNEL immunostaining was conducted on
sequential sections using the In Situ Cell Death Detection Kit
POD (Roche Applied Sciences, Indianapolis, IN). Sections
were counterstained with Harris hematoxylin. Slides were
imaged under a light microscope (×200 magnification),
and images were captured using a SPOT insight color digi-
tal camera and analysis software (Diagnostic Instruments).
Positive nuclei were counted to determine the apoptotic and
proliferation indices, as previously described.8
Statistical Evaluation of Data
Statistical methods used to analyze the data consisted of the
Student t-test, analysis of variance (ANOVA) techniques,
and the Kruskal-Wallis test. All tests were two-sided and
conducted at the .05 level of significance.
For the in vitro studies, the outcomes of interest were cell
growth, cell cycle progression, and cell death. The Student
t-test was used to determine if the pao pereira extract induced
significant effects on these outcomes in comparison with
the control conditions. For the in vivo study, outcomes of
interest were rate of change in log tumor volume over time,
change in final log tumor volume from baseline, baseline
and final tumor volume, and percent positive staining nuclei
per total cells for the BrdU and TUNEL assays. Owing to the
skewed nature of some of the tumor volume–related out-
comes, the Kruskal-Wallis test was applied to assess differ-
ences among the dose groups where appropriate. Log tumor
volume measurements over time for the different treatment
groups were also presented graphically. Differences in per-
cent positive staining nuclei per total cells between control
and pao pereira–treated mice for both BrdU and TUNEL
assays were assessed using a Student t-test.
Effects of Pao Pereira Extract on LNCaP Cell Growth
and Apoptosis In Vitro
In vitro growth of LNCaP cells was significantly reduced fol-
lowing treatment with 100 or 500 µg/mL pao pereira extract
(p < .001, Student t-test) compared with vehicle-treated cells
(Figure 1). There was a striking dose-dependent difference in
growth inhibition between the 100 and 500 µg/mL doses, with
a greater than 90% suppression of growth at the 500 µg/mL
dose. Fluorescence-activated cell sorter (FACS) analysis
showed that there was no significant effect on the overall
cell cycle distribution of cells treated at 100 µg/mL; how-
ever, at 500 µg/mL, there was a significant reduction in the
percentage of cells in the S and G2/M phases of the cell cycle
and increased accumulation in the sub-G1/G0 population
(cells containing subgenomic levels of deoxyribonucleic acid
[DNA]) (Figure 2). The increased number of cells in sub-
G1/G0 indicated that the 500 µg/mL dose induced cell death that
was not observed at 100 µg/mL. To determine if the cell death
was the consequence of apoptosis, protein lysates from pao
pereira–treated (500 µg/mL) or control cells were analyzed for
the presence of cleaved poly (adenosine diphosphate [ADP]-
ribose) polymerase (PARP) by Western blot analysis. Extensive
PARP cleavage was observed in cells treated for 24 hours with
pao pereira but not in control cells (data not shown).
In Vivo Effects of Pao Pereira on LNCaP Xenograft
Volume and Tumor Cell Proliferation or Apoptosis
To determine if the pao pereira extract could suppress the
in vivo growth of LNCaP tumor xenografts, male immuno-
deficient mice were subcutaneously xenografted with 1 × 106
LNCaP cells and the mice were randomly divided into groups,
Percent of Control
0 24 48 72
Time (hr)
100 µg/mL
500 µg/mL
1.Figure Pao pereira extract suppresses in vitro cell growth
in the human prostate cancer cell line LNCaP. *p < .001,
Student t-test.
60 Control
100 µg/mL Pao
500 µg/mL Pao
Sub GO G1 S G2/M
% of Total Cell Population
Cell Cycle Phase
2.Figure Analysis of LNCaP cell cycle progression following
24-hour treatment with pao pereira extract. *p < .01, Student
059-065_JSIO_2009_0009.indd 61 3/29/09 1:42:56 AM
62 Journal of the Society for Integrative Oncology, Spring 2009, Volume 7, Number 2
each of which was gavaged daily with vehicle or with 10, 20,
or 50 mg/kg/d of the pao pereira extract. The extract did not
appear to affect the overall health of the mice as no signifi-
cant difference in weight was observed over the study period
across the treatment or control groups (ANOVA-based
F-test, p = .3852) (Figure 3). However, the tumor volumes
at the first measurement were already significantly lower
in the 10 and 20 mg/kg treated groups (Figure 4; Kruskal-
Wallis test, p = .025). Also, by the end of the experiment,
median tumor volumes in the 10 and 20 mg/kg treatment
groups were decreased by 80% and 75%, respectively, com-
pared with the vehicle control group (Kruskal-Wallis test,
p = .021). The tumor-suppressing effect of the pao pereira
extract was apparently lost at the highest dose (50 mg/kg/d)
as the distribution of tumor volume at both baseline and the
end of the study in this group was not statistically different
from that of vehicle-treated controls.
Change in tumor volume over time was evaluated by
considering both the rate of change in log tumor volume and
the difference in final log tumor volume from baseline (see
Figure 4B). There was no evidence of differences in tumor
volume behavior over time across the dosing groups for
these two outcomes (p = .792 and p = .682, respectively).
These results then suggest that the 10 mg/kg and 20 mg/kg
doses slowed the ability of the tumor cells to establish them-
selves and grow within the subcutaneous environment of the
mice compared with the control or the 50 mg/kg treatment
The effect of the extract on tumor cell proliferation was
analyzed by immunohistochemical detection of BrdU incor-
poration into tumor cell nuclei. A quantitative assessment of
Mouse Weight (g)
0 10 20 30 40
Time (days)
10 mg/kg
20 mg/kg
50 mg/kg
3.Figure Average mouse weights of the pao pereira treatment
and control groups. *p = .3852, ANOVA-based F-test.
Tumor Volume (mm3)
Dose Group (pao pereira mg/kg)
0 10 20
4.Figure Effect of pao pereira extract (10, 20, and 50 mg/kg) on
LNCaP tumor xenograft growth in immunodeficient mice A, Box
plot of baseline tumor volumes for control and pao pereira treat-
ment groups. A statistically significant difference was observed
across all dose groups (p = .025, Kruskal-Wallis test). B, Overall
tumor volume in mouse xenografts was reduced in 10 mg/kg and
20 mg/kg pao pereira–treated mice. *p = .005, ANOVA (median
log tumor volume).
50 mg/kg
* 10 mg/kg
Time (days following treatment initiation)
* 20 mg/kg
15 23 32 41
Log Tumor Volume
the average number of BrdU-positive nuclei revealed that
all treatment groups induced statistically significant reduc-
tions in overall tumor cell BrdU incorporation, as shown
in Figure 5 (Student t-test, p < .001). The 10 mg/kg and
20 mg/kg extract reduced tumor cell proliferation by 52%
and 73%, respectively. Although the 50 mg/kg dose inhib-
ited tumor cell proliferation by 46% compared with the
control group (Student t-test, p < .001), the effect was
not different from that caused by the 10 mg/kg dose, sup-
portive of a biphasic dose response. Additionally, tumor
sections from all mice were analyzed by TUNEL staining
to detect cells undergoing apoptosis (Figure 6A). As illus-
trated in Figure 6B, TUNEL-positive nuclei were signifi-
cantly increased by 1.6-fold and 2.6-fold in the 10 mg/kg
and 20 mg/kg groups, respectively, compared with con-
trol levels (Student t-test, p < .05). The 50 mg/kg dose
did not induce tumor cell apoptosis over control levels
(p > .05). Again, a trend toward a biphasic dose response
059-065_JSIO_2009_0009.indd 62 3/29/09 1:42:58 AM
Bemis et al, Pao Pereira Suppresses Prostate Cancer 63
in vitro and in vivo, and it supports the idea that other plants
rich in B-carbolines might also be natural sources of prostate
cancer preventive or therapeutic agents.
Although we do not understand the mechanism(s)
through which the pao pereira extract affects prostate can-
cer cell growth and survival, we presume that the effects
of this agent might be related to the B-carboline alkaloids.
B-Carboline alkaloids suppress CDK activity5 that is needed
to drive normal and cancerous cells through the cell cycle,
but they also bind to DNA and may cause other cellular
anomalies specific to cancer cells that suppress cell division
or induce cell death. In our previous work with R. vomitoria
extract, we used a targeted microarray analysis approach to
evaluate the effects of the extract on gene expression patterns
in LNCaP cells, especially on genes involved in DNA dam-
age repair.8 We reported that numerous genes involved in
DNA damage and repair were modulated by this extract. We
did perform a similar but preliminary (unvalidated) analysis
using the same DNA damage and repair microarray to com-
pare gene expression in pao pereira–treated (100 µg/mL)
LNCaP cells with that in control (vehicle treated) cells, but
much fewer and different genes were affected in this path-
way compared with treatment with the Rauwolfia extract.
In our assay using pao pereira–treated cell complementary
DNA, we observed particularly strong upregulation of the
DNA repair response genes BRCA1 (24.67-fold) and DDIT3
was evident, suggesting that the 50 mg/kg pao pereira was
beyond the optimal dose required to induce maximal tumor
cell apoptosis.
Prostate cancer is a problematic human disease whose bur-
den to health in the United States could be decreased by a
suitable preventive agent or treatment, especially one that
might be used as a nutritional supplement. Here we tested
whether a B-carboline-rich extract of pao pereira bark might
have any efficacy in suppressing in vitro or in vivo growth of
a prototypic human prostate cancer cell line, LNCaP. Our
results showed that this extract, when added to the medium of
cultured LNCaP cells, suppressed their growth and induced
apoptosis in a dose-dependent manner. Furthermore, when
pao pereira extract was gavaged into mice that had been
xenografted with LNCaP cells, tumor size was significantly
smaller in two of three groups of treated mice compared with
the tumor size in vehicle-treated mice over the experimen-
tal period. To some extent, this response was similar to our
previous finding that a B-carboline-rich extract of another
medicinal plant, R. vomitoria, also suppressed LNCaP growth
10 mg/kg 20 mg/kg 50 mg/kg
Pao Pereira Extract (50 mg/kg)
% TUNEL Positive/Field (Avg.)
00 10 20 30
6.Figure Six-week oral dosing of pao pereira extract–induced
apoptosis in LNCaP tumor xenografts. A, Cells undergoing apop-
tosis stained brown (TUNEL staining; ×200 magnification). B,
Quantification of apoptotic cells in LCNaP tumor xenografts from
each treatment group. Error bars indicate ± SEM; *p < .05, Student
Control 50 mg/kg
Pao Pereira Extract (mg/kg)
% Brdu Positive/Field (Avg.)
10 20 50
5.Figure Inhibition of proliferation in LNCaP tumor xeno-
grafts following 6-week gavage of pao pereira extract. A, Cells
stained dark blue represent proliferating cells (BrdU incorpo-
ration; ×200 magnification). B, Quantification of proliferating
cells in LNCaP tumor xenografts. Errors bars indicate ± SEM;
*p < .05, Student t-test.
059-065_JSIO_2009_0009.indd 63 3/29/09 1:43:00 AM
64 Journal of the Society for Integrative Oncology, Spring 2009, Volume 7, Number 2
agent(s) present and that the tumor cell–protective effect is
manifest at the higher doses of the extract.
According to the Mertz model, a U-shaped dose-response
relationship exists between essential nutrients and their bio-
logic impact; therefore, the optimal concentration of these
agents required to achieve their desired biologic effects is in
the midrange of the dose-response curve.10 Several studies
have reported that this relationship also applies to anticancer
nutritional agents,11–13 and our data using pao pereira extract
also appear to validate this idea. Regardless, our data dem-
onstrate the anti–prostate cancer activities of the pao pereira
extract in both in vitro and in vivo prostate cancer cell model
systems, and this work indicates the need for continued
exploration into its use in the prevention and/or treatment
of prostate cancer.
Financial disclosure of authors: This research was supported
by The Center for Holistic Urology at Columbia University
Medical Center, The Charles Royce Foundation, and Natural
Source International, Ltd.
Financial disclosure of reviewers: None reported.
1. Beljanski M, Crochet S. The selective anticancer
agents PB-100 and BG-8 are active against human
melanoma cells, but do not affect non malignant
fibroblasts. Int J Oncol 1996;8:1143–8.
2. Beljanski M, Crochet S. The selective anticancer agent
PB-100 inhibits interleukin-6 induced enhancement
of glioblastoma cell proliferation in vitro. Int J Oncol
3. Beljanski M. The anticancer agent PB-100, selectively
active on malignant cells, inhibits multiplication of
sixteen malignant cell lines, even multidrug resistant.
Genet Mol Biol 2000;23:29–33.
4. Beljanski M, Beljanski MS. Three alkaloids as selective
destroyers of cancer cells in mice: synergy with classic
anticancer drugs. Oncology 1986;43:198–203.
5. Cao R, Peng W, Wang W, Xu A. betal-carboline alka-
loids: biochemical and pharmacological functions.
Curr Med Chem 2007;14:479–500.
6. American Cancer Society. Cancer facts and figures
2008. Atlanta: American Cancer Society, 2008.
7. Caffo O, Sava T, Comploj E, et al. Docetaxel, with
or without estramustine phosphate, as first-line
(14.6-fold change) compared with vehicle-treated cells.
More striking, however, were the changes in the expression
of genes associated with the apoptosis pathway, where BAX
(13-fold), TNFRSF11B (a member of the tumor necrosis
factor receptor family; 12-fold), and APAF1 (9.5-fold) were
most strongly upregulated. These results, although not yet
validated by polymerase chain reaction studies, suggest that
the Rauwolfia and pao pereira extracts may have different
mechanisms of action that might even be complementary
with regard to an anticancer effect.
One of the most striking and enigmatic results of our
study, however, was the finding that the greatest effect of pao
pereira extract on in vivo tumor growth (size) occurred at the
lower doses tested (10 and 20 mg/kg/d). In these groups, pao
pereira extract treatment reduced tumor volume by 80% and
75%, respectively. In contrast, mice gavaged with a 50 mg/
kg/d dose actually had mean tumor volumes at the end of the
experiment that were similar to those of vehicle-treated mice.
These discrepant results were also reflected by our analysis
of the effects of pao pereira extract on tumor cell apoptosis
(measured by TUNEL staining). Whereas the 20 mg/kg/d
dose of pao pereira extract increased tumor cell apoptosis
in the LNCaP xenografts by > 2.5-fold, the 50 mg/kg/d dose
did not significantly increase apoptosis.
At this time, we do not understand the reason(s) for this
unusual treatment effect. All groups were gavaged daily at
the same times by the same investigators, and the doses were
made from the same stock of pao pereira extract dissolved in
6% DMSO. Although there was no difference in tumor size
in vehicle-treated versus 50 mg/kg/d extract–treated groups,
treatment at the high dose did significantly suppress prolifer-
ation of the tumor cells, so the treated mice were experienc-
ing some effects of the extract, but these were not sufficient
to influence tumor size. Other potential explanations for
this effect might include gastrointestinal consequences at the
higher dose that suppresses uptake of active agents. We note
here again that the mice did not suffer weight loss, which
might reflect a general failure of gastrointestinal absorption
at higher doses, nor did we notice other symptoms of gas-
trointestinal distress, such as diarrhea, in any treated group.
It is also possible that high concentrations of pao pereira
extract could induce metabolic enzymes, potentially altering
the chemical profile of the bioactive compounds to an inac-
tive state. The effects of the pao pereira preparation on mice
are likely a composite of the effects of the extract in multiple
organ systems, unlike single cells in cell culture. Finally, we
must consider the possibility that the complex nature of pao
pereira extract allows for the potential presence of ingre-
dients that oppose the actions of any cancer-suppressing
059-065_JSIO_2009_0009.indd 64 3/29/09 1:43:00 AM
Bemis et al, Pao Pereira Suppresses Prostate Cancer 65
chemotherapy for hormone-refractory prostate can-
cer: results of a multicentre, randomized phase II trial.
BJU Int 2008;May 15 [Epub].
8. Bemis DL, Capodice JL, Gorroochurn P, et al. Anti-
prostate cancer activity of a beta-carboline alkaloid
enriched extract from Rauwolfia vomitoria. Int J Oncol
9. Taguchi A, Blood DC, del Toro G, et al. Blockade of
RAGE-amphoterin signalling suppresses tumour
growth and metastases. Nature 2000;405:354–60.
10. Mertz W. The essential trace elements. Science 1981;
11. Waters DJ, Shen S, Glickman LT, et al. Prostate can-
cer risk and DNA damage: translational significance
of selenium supplementation in a canine model.
Carcinogenesis 2005;26:1256–62.
12. Leitzmann MF, Stampfer MJ, Wu K, et al. Zinc supple-
ment use and risk of prostate cancer. J Natl Cancer Inst
13. Nyberg F, Hou SM, Pershagen G, et al. Dietary fruit
and vegetables protect against somatic mutation in
vivo, but low or high intake of carotenoids does not.
Carcinogenesis 2003;24:689–96.
059-065_JSIO_2009_0009.indd 65 3/29/09 1:43:00 AM
... Studies with isolated indole alkaloids, extracts and fractions of different parts of Geissospermum spp. have reported antitumor pharmacological (Bastos, 2017;Bemis et al., 2009;Chang et al., 2014;Liu et al., 2019;Sajkowska-Kozielewicz et al., 2016;Yeh et al., 2019;Yu and Chen, 2014), antinociceptive, anti-inflammatory (Lima et al., 2016;Werner et al., 2009), anticholinesterase (Araújo et al., 2011;Lima et al., 2020Lima et al., , 2009, antileishmania, antitrypanosoma(da Silva e Silva et al., 2019;Reina et al., 2012), anti-HIV (Beljanski, 2005), antimicrobial (Camargo, 2011;Correia et al., 2008;Dias, 2012;Saraiva, 2012), cardiovascular (Martins, 2010;Morais, 2012), antioxidant (Sajkowska-Kozielewicz et al., 2016), and antimalarial (Bertania et al., 2005;Camargo, 2011;Mbeunkui et al., 2012;Muñoz et al., 2000;Oliveira, 2018;Steele et al., 2002). ...
... Almeida et al. 2009 Beta-carboline alkaloid-enriched extract from the amazonian rain forest tree pao pereira suppresses prostate cancer cells. Bemis et al. 2009 Geissospermum vellosii STEMBARK. Anticholinesterase activity and improvement of scopolamine-induced memory deficits. ...
... Tumor growth was suppressed by up to 80% in some groups compared to tumors in vehicle-treated control mice.Doses at the concentration of 10 or 20 mg/kg/day were best for inducing tumor cell apoptosis as opposed to higher doses. The researchers suggested that while the study demonstrated the activity of an extract of the bark of this tree against human prostate cancer, the results of their in vivo studies suggest that its potential effectiveness in treating prostate cancer may be limited to a narrow dose range(Bemis et al., 2009).The anticancer effects of the extract enriched with β-carboline alkaloids from G. velossi alone and in combination with carboplatin were investigated. The results showed a selective inhibition of ovarian cancer cell growth with IC50 values of 180-235 µg/ml compared to 537 µg/ml in normal cells. ...
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This narrative review aims to update the ethnopharmacology, phytochemistry and biological activities of Geissospermum species described in the literature, in order to contribute to the knowledge of bioactive compounds of therapeutic interest and establish directions for future research with this genus. The term “Geissospermum” was used to perform searches in different databases such as NDLTD (Digital Library Network of Theses and Dissertations), Google Scholar, PubChem, Scifinder, Web of Science, SciELO, PubMed and Science Direct. Google's National Institute of Industrial Property and Patents (INPI) was also consulted. The keywords indole alkaloids, quina-quina, Geissospermum, Geissospermum reticulatum and malaria were used in the search. Publications in Portuguese, French, Spanish and English published between 1950 and 2022 were included. Indole alkaloids are the main secondary metabolites found in this genus, and several molecules have already been isolated, which may be related to the described pharmacological activities. Extracts and isolated compounds showed antitumor, antimalarial, antinociceptive, anti-inflammatory, anticholinesterase, anti-HIV, antimicrobial and antioxidant activity. Plants of the genus Geissospermum are used in Brazil mainly by the Amazonian peoples to treat various pathologies. Biological activities reported for extracts and isolated compounds are consistent with etonopharmacological use against malaria, cancer and other diseases. Future work with Geissospermum species is needed to elucidate the mechanism of action of the isolated alkaloids, as well as their toxicological profile.
... The bark of Pao pereira shows anti-plasmodial, antinociceptive and anti-inflammatory activities 23,24 . Recent studies revealed that a β-carboline alkaloid-enriched Pao extract has inhibitory effects on two prostate cancer lines, LNCaP and PC3 by inhibiting cell proliferation and survival 25,26 . Moreover, Pao extract can also chemosensitize ovarian cancer cells to carboplatin and pancreatic cancer cells to gemcitabine, respectively [27][28][29] . ...
... Pao extract, derived from bark of Amazonian tree Pao Pereira, is commonly used in South American medicine to treat a variety of ailments including cancer 23,24 . We and others have reported that Pao extract can inhibit human prostate cancer cell proliferation and survival in vitro and in vivo 25,26 . However, there is no evidence on its effects on BPH. ...
... Since activation of AR by binding with testosterone or DHT induce cell cycle gene expression, including Cyclin D1 42 , Pao extract may inhibit Cyclin D1 expression through reducing 5α reductase level and AR activity. Consistent with the suppressive effects of Pao extract on highly proliferative cells in BPH model, we and other group have demonstrated that Pao extract induced cell growth arrest and apoptosis in LNCaP and PC3 prostate cancer cells, as well as ovarian and pancreatic cancer cells 25,26 . In addition, Pao extract has been shown to inhibit multiple signaling pathways other than hormone-related signaling, such as Wnt/β-catenin and NFκB signaling in various cancer cells 27,29 . ...
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Benign prostatic hyperplasia (BPH) is one of the most common diseases in the urinary system of elderly men. Pao extract is an herbal preparation of the bark of the Amazon rainforest tree Pao Pereira (Geissospermum vellosii), which was reported to inhibit prostate cancer cell proliferation. Herein we investigated the therapeutic potential of Pao extract against BPH development in a testosterone-induced BPH rat model. The administration of testosterone induced the prostate enlargement, compared with the sham operated group with vehicle treatment. The BPH/Pao group showed reduced prostate weight comparable with BPH/finasteride group. Notably, Pao treatment did not significantly reduce body weights and sperm number of rats, compared with the control group. Furthermore, Pao extract treatment reduced the proliferative index in prostate glands and testosterone-induced expression levels of AR, as well as androgen-associated proteins such as SRD5A1 and PSA. Moreover, Pao extract and its active component, flavopereirine, induced cytotoxicity on human prostate epithelial RWPE-1 cells in a dose- and time- dependent manner with G2/M arrest. Consistently, Pao extract and flavopereirine suppressed the expression levels of SRD5A1, AR and PSA, respectively. Together, these data demonstrated that Pao extract suppresses testosterone-induced BPH development through inhibiting AR activity and expression, and suggested that Pao extract may be a promising and relative safe agent for BPH.
... Likewise, a natural blend of Geissospermum laeve (Vell.) Miers (Pao pereira tree, containing flavopereirine) and Rauvolfia vomitoria (containing alstonine) have been proven to be effective against brain, kidney, pancreatic, skin, colon, breast, liver, and prostate cancer cells (Bemis et al., 2009;Okon et al., 2017). ...
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Alstonine is an indole alkaloid found abundantly in some traditional plants. In some parts of the world, including Nigeria and India, plants containing alstonine have been used to cure mental illness, dysentery, and typhoid, among others. The current review describes the pharmacological activities of alstonine. The search phrases "alstonine," "biological activity," and "pharmacological activity" were used to query Google Scholar, PubMed Central, Web of Science, Scopus, and Base databases. It was established that alstonine has chemotherapeutic properties by acting as an intercalating agent and inducing apoptosis and DNA damage in cancer cells. In addition, alstonine has antipsychotic properties, mostly through its ability to increase seroto-nergic transmission while simultaneously altering dopamine metabolism. Furthermore, alstonine's anxiolytic and antiplasmodial properties have been shown to involve inhibiting haloperidol-induced catalepsy and the subsequent mediation of mitochondrial apoptosis in Plasmodium falciparum. In spite of its interesting biological activities, several aspects of alstonine properties such as toxicity and pharmacokinetics are relatively underreported.
... This family of plants has been used as folk medicines in South American and Africa to treat a variety of health related conditions, such as hypertension, 22,23 fever, 24,25 gastrointestinal diseases, 26 liver diseases, 27 and cancers. 28,29 The extracts of Pao and Rau each as a mixture are used as health supplements. Extracts from Pao and Rau are enriched with β-carboline alkaloids and indole alkaloids. ...
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Ovarian cancer has an enrichment of cancer stem cells (CSCs) which contribute to the treatment resistant tumor’s high rate of recurrence and metastasis. Here we investigated 2 plant extracts from the medicinal plants Pao Pereira (Pao) and Rauwolfia vomitoria (Rau) each for their activities against ovarian CSCs. Both Pao and Rau inhibited overall proliferation of human ovarian cancer cell lines with IC 50 ranging from 210 to 420 μg/mL and had limited cytotoxicity to normal epithelial cells. Ovarian CSC population was examined using cell surface markers and tumor spheroid formation assays. The results showed that both Pao and Rau treatment significantly reduced the ovarian CSC population. Pao and Rau had similar activities in inhibiting ovarian CSCs, with IC 50 s of ~120 μg/mL for 24 hours treatment, and ~50 μg/mL for long-term tumor spheroid formation. Nuclear β-catenin levels were decreased, suggesting suppression of Wnt/β-catenin signaling pathway. Taken together, data here showed that Pao and Rau both inhibited ovarian cancer stem cells, probably in preference to the bulk of tumor cells. Further mechanistic studies and in vivo investigation validating these findings are warranted, given that inhibition of cancer stem cells holds the promise of comprehensively inhibiting cancer metastasis, drug resistance and recurrence.
... In fact, among 12 species, only six (G. argenteum, G. fuscum, G. leave, G. reticulatum, G. sericeum, and G. urceolatum) have been studied phytochemically [1,3,[5][6][7][8][9][10][11][12][13][14]. Specifically, it has been reported that these trees are a rich source of indole alkaloids [1,3]. ...
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A new alkaloid, geissospermiculatine was characterized in Geissospermum reticulatum A. H. Gentry bark (Apocynaceae). Here, following a simplified isolation protocol, the structure of the alkaloid was elucidated through GC-MS, LC-MS/MS, 1D, and 2D NMR (COSY, ROESY, HSQC, HMBC, 1H-15N HMBC). Cytotoxic properties were evaluated in vitro on malignant THP-1 cells, and the results demonstrated that the cytotoxicity of the alkaloid (30 μg/mL) was comparable with staurosporine (10 μM). Additionally, the toxicity was tested on zebrafish (Danio rerio) embryos in vivo by monitoring their development (0–72 h); toxicity was not evident at 30 μg/mL.
... Pao pereira (Geissospermum vellosii) is an Amazon rainforest tree, and its bark extract is used to treat malaria, digestive disorders and cancers. Pao extract is rich in β-carboline alkaloids [8] and exhibited antiproliferative activities against melanoma and glioblastoma, ovarian cancer and pancreatic cancer [9][10][11][12][13]. Our previous study showed that Pao extract decreased human prostate cancer cell growth via inducing apoptosis [14]. ...
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Background: Our previous study revealed the extract from the bark of an Amazonian tree Pao Pereira can suppress benign prostatic hyperplasia (BPH) in a rat model. Herein, we examined its inhibitory effects on human BPH cells and dissect its molecular mechanism. Methods: We applied Pao extract to human BPH epithelial BPH-1 and prostate myofibroblast WPMY-1 cells. Cell viability, apoptosis and immunoblotting were performed, followed by gene expression profiling and gene set enrichment analysis (GSEA) to detect the differentially expressed genes and signaling pathway induced by Pao extract. Human ex vivo BPH explant organ culture was also used to examine the effects of Pao extract on human BPH tissues. Results: Pao extract treatment inhibited viability and induced apoptosis in human BPH-1 and WPMY-1 cells. Gene expression profiling and the following validation indicated that the expression levels of pro-apoptotic genes (eg. PCDC4, CHOP and FBXO32) were induced by Pao extract in both two cell lines. GSEA further revealed that Pao extract treatment was negatively associated with the activation of NFκB signaling. Pao extract suppressed the transcriptional activity of NFκB and down-regulated its target genes involved in inflammation (CXCL5, CXCL6 and CXCL12) and extracellular matrix (ECM) remodeling (HAS2, TNC and MMP13) in both cultured cells and human ex vivo BPH explants. Conclusion: In both BPH epithelial and stromal cells, Pao extract induces apoptosis by upregulating the pro-apoptotic genes and inhibiting the inflammation-associated NFκB signaling via reducing phosphorylation of NFκB subunit RelA. Our data suggest that Pao extract may be a promising phytotherapeutic agent for BPH.
... 59,60 Besides alkaloids, several other compounds may be present on the surface of each individual sample where light is scattered and the information obtained reflects the outer layer of the material. In this work, and in several reports from the literature 1,14,25,[59][60][61][62] it has been demonstrated that the ethanolic and methanolic extractions without further treatment have furnished a mixture of alkaloids rich in indoline, indole and indoline/indole moieties. ...
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Pau-pereira (Geissospermum vellosii) is a native tree of Brazil from which a mixture of alkaloids named pereirine and the compound flavopereirine has been isolated. Preventive and curative properties have been recorded by ethnopharmacological studies performed with Geissospermum species. Pereirine has been prescribed as a herbal drug since the early 1830's and flavopereirine has shown anticancer properties. In this work, the alkaloid content produced by G. vellosii has been investigated from 20 commercial samples collected from different localities. The identification of compounds has been performed by Raman and surface-enhanced Raman scattering (SERS) spectroscopies, with the assignment of Raman bands supported by theoretical calculations. The obtained results have demonstrated that Raman and SERS techniques are suitable to detect both pereirine and flavopereirine from raw materials, infusions prepared as teas and ethanolic extracts, which is the extraction procedure to prepare tinctures. Chemometric analysis was able to discriminate the alkaloid content present in each sample type according to the extraction methodology.
... Besides alkaloids, several other compounds may be present at the surface of each individual sample where the light is scattered and the information obtained reflects the outer layer of the material. In this work, as well in several reports from literature [1,14,25,[59][60][61][62] it has been demonstrated that the ethanolic and methanolic extractions without further treatment have furnished a mixture of alkaloids rich of indoline, indole and indoline/indole moieties. ...
Pau-pereira (Geissospermum vellosii) is a native tree of Brazil from which has been isolated a mixture of alkaloids named pereirine and the compound flavopereirine. Preventive and curative properties have been recorded by ethnopharmacological studies performed with Geissospermum species. Pereirine has been prescribed as herbal drug since early 1830’s and flavopereirine has presented anticancer activities. In this work, it has been investigated from 20 commercial samples collected in different localities, the alkaloid content produced by G. vellosii. The identification of compounds has been performed by Raman and surface-enhanced Raman scattering (SERS) spectroscopies, with the assignment of Raman bands supported by theoretical calculations. The obtained results have demonstrated that Raman and SERS techniques are suitable to detect both pereirine and flavopereirine from raw materials, infusions prepared as teas and ethanolic extracts, which is the extraction procedure to prepare tinctures. The chemometric analysis was able to discriminate the alkaloids content present in each sample type according to extraction methodology.
This review is a brief treatise on some simple β-carboline alkaloids that are abundantly available in plants, animals and foodstuff. These alkaloids are well known for their pharmacological action as well as their allelopathic behaviour. The focus of this review is on sustainable use of naturally occurring compounds in safeguarding human health and protecting our environment at large i.e. the prospective applications of these molecules for Sustainable Theranostics . The review commences with an initial introduction to the β-carboline alkaloids, followed by an outlay of their geographical distribution and natural abundance, then the basic structure and building units of the simplest β-carboline alkaloids have been mentioned. This is followed by a discussion on the important methods of extraction from natural sources both plants and animals. Then the foundation for the use of these alkaloids in Sustainable Theranostics has been built by discussing their interesting photophysics, interactions with important biological molecules and an extensive survey of their therapeutic potential and allelopathic behaviour. Finally the review ends with a silver lining mentioning the future prospective applications of these alkaloids with special relevance to sustainability issues.
A number of analytical studies, started in the sixties of the last century, concerning the stem bark of Geissospermum vellosii, have documented the presence of a number of indole alkaloids whose molecular identity was defined by NMR technique. The potential bioactivity of these compounds has inspired more recent analogous studies either devoted to structural elucidation of new alkaloid molecules or to the investigation of the role of some of them in cancer therapy. Anyway, a complete fingerprinting of the bark content is still lacking. In this paper, after a suitable extraction step, we obtain a chromatographic separation showing a number of components higher than the number of alkaloids so far described. Considering the great number of substances present in the stem bark, their identification is practically impossible to reveal by NMR techniques. As we presume that there are other stem bark unidentified alkaloids with important bioactivity, we propose to characterize their molecular structures by UV–Vis Diode Array spectrophotometry and High-Resolution Multistage Mass Spectrometry. The two adopted detection techniques were first tested on the already known Geissospermum vellosii molecules, and, after an inspection of their efficacy, were applied to the substances that have not yet been described. Herewith we propose the molecular structures of 10 substances that were never previously described, and in addition we provide experimental evidence of the presence of 6 already known substances which were never reported in the Geissospermum genus. A far more detailed description of the bark constituents is therefore provided.
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The plant-derived anticancer agent PB-100 selectively destroys cancer cells, even when multidrug resistant; yet, it does not inhibit normal (non-malignant) cell multiplication. Testing of PB-100 on sixteen malignant cell lines, several multidrug resistant, as well as on five normal cell lines, confirmed our previous results. Flavopereirine and dihydroflavopereirine, the active principles of PB-100, were chemically synthesized and displayed the same selectivity for tumor cells as the purified plant extract, being active at even lower concentrations.
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The receptor for advanced glycation end products (RAGE), a multi-ligand member of the immunoglobulin superfamily of cell surface molecules, interacts with distinct molecules implicated in homeostasis, development and inflammation, and certain diseases such as diabetes and Alzheimer's disease. Engagement of RAGE by a ligand triggers activation of key cell signalling pathways, such as p21ras, MAP kinases, NF-kappaB and cdc42/rac, thereby reprogramming cellular properties. RAGE is a central cell surface receptor for amphoterin, a polypeptide linked to outgrowth of cultured cortical neurons derived from developing brain. Indeed, the co-localization of RAGE and amphoterin at the leading edge of advancing neurites indicated their potential contribution to cellular migration, and in pathologies such as tumour invasion. Here we demonstrate that blockade of RAGE-amphoterin decreased growth and metastases of both implanted tumours and tumours developing spontaneously in susceptible mice. Inhibition of the RAGE-amphoterin interaction suppressed activation of p44/p42, p38 and SAP/JNK MAP kinases; molecular effector mechanisms importantly linked to tumour proliferation, invasion and expression of matrix metalloproteinases.
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The high concentration of zinc in the prostate suggests that zinc may play a role in prostate health. We examined the association between supplemental zinc intake and prostate cancer risk among 46 974 U.S. men participating in the Health Professionals Follow-Up Study. During 14 years of follow-up from 1986 through 2000, 2901 new cases of prostate cancer were ascertained, of which 434 cases were diagnosed as advanced cancer. Supplemental zinc intake at doses of up to 100 mg/day was not associated with prostate cancer risk. However, compared with nonusers, men who consumed more than 100 mg/day of supplemental zinc had a relative risk of advanced prostate cancer of 2.29 (95% confidence interval = 1.06 to 4.95; P(trend) =.003), and men who took supplemental zinc for 10 or more years had a relative risk of 2.37 (95% confidence interval = 1.42 to 3.95; P(trend)<.001). Although we cannot rule out residual confounding by supplemental calcium intake or some unmeasured correlate of zinc supplement use, our findings, that chronic zinc oversupply may play a role in prostate carcinogenesis, warrant further investigation.
Epidemiological studies have demonstrated protective effects of vegetables and fruit on risk of cancer, but underlying mechanisms remain unclear. Intervention studies have in some cases contradicted previous epidemiological evidence, e.g. for beta-carotene supplementation and lung cancer, emphasizing the need for mechanistic data. We assessed in vivo mutagenic effects of several dietary items using the HPRT (hypoxanthine-guanine phosphoribosyl transferase) gene assay with T-lymphocytes from 312 individuals (158 lung cancer cases, 154 population controls), who provided information on diet and smoking habits. HPRT mutant frequency (MF) was significantly decreased in relation to intake of vegetables, citrus fruits and berries, respectively, as well as calculated vitamin C intake from diet. There was a significant U-shaped association with dietary carotenoid intake, with lowest MF near population average carotenoid intakes and higher mutation frequencies both at low and high intakes, and a similar borderline significant association was observed for beta-carotene. Our study is consistent with known diet-cancer associations and provides novel human in vivo mechanistic support for a cancer-protective effect of vegetables and fruit by modulation of somatic mutagenesis. Our results also provide support for the increase in lung cancer risk observed particularly in smokers in studies of beta-carotene supplementation.
The multifunctional cytokine interleukin-6 behaves as a growth factor for various malignancies. It is produced in significant amounts by glioblastoma cells. When exogenous IL-6 is added (pg/ml) to culture medium of human glioblastoma cells and normal (non malignant) astrocytes used as controls, it exerts a dose dependent and differential effect on these two cell lines. Enhancement of cell proliferation is twice as high for glioblastoma cells as for astrocytes. In vitro, the novel anticancer agent PB-100 (mu g/ml) dose dependently inhibits this stimulatory activity. In addition, increasing PB-100 concentrations finally induce death of the malignant cells, yet do not impede multiplication of normal astrocytes. PB-100 does not abolish IL-6 production by cells, but keeps its level down to physiological values. PB-100 should therefore find its place in therapies requiring control of IL-6 production.
When past the stage amenable to surgery, melanoma and its metastases are, as a rule, treated with chemotherapy, which is largely unsuccessful. In this report, experimental evidence is presented demonstrating that, in vitro, two selective anticancer agents, PB-100 and BG-8, dose dependently destroy human G-361 melanoma cells, but do not affect human non malignant CCD-974Sk fibroblasts used as controls. Trace metal compounds, present, often in abnormal amounts, in the cancer cell and/or its environment, are known to influence its proliferation. Assays were carried out using highly elevated amounts of ferritin, iron chloride or zinc chloride. Ferritin proved differentially mitogenic for melanoma cells and fibroblasts. Its activity was inhibited by both anticancer agents, which however tended to become less efficacious in its presence. FeCl3 was more moderately, but equally, mitogenic for malignant and normal cells, yet it impaired antiproliferative activity of PB-100 and inhibited that of BG-8. ZnCl2 exhibited a selective antiproliferative activity on the malignant melanoma cells; it did not compete with PB-100 or BG-8. Specific recognition and destruction of malignant cells by the two anticancer agents are discussed.
Alstonine, serpentine and sempervirine, when used at appropriate concentrations cure a relatively important proportion of BALB/C mice inoculated with transplantable YC8 lymphoma ascites cells, as well as Swiss mice bearing Ehrlich ascites carcinoma cells. The development of some solid tumors was only partially prevented. However, when one alkaloid was administered in association with either 5-FU, daunorubicin, 1-(2-chloroethyl) nitrosourea (CCNU) or cyclophosphamide (CP) to mice bearing either ascites carcinoma cells or solid tumors, a high rate of cure was obtained without toxicity. The role of the three alkaloids in the curing of mice and prevention of carcinogenesis is discussed.
Essential trace elements are required by man in amounts ranging from 50 micrograms to 18 milligrams per day. Acting as catalytic or structural components of larger molecules, they have specific functions and are indispensable for life. Research during the past quarter of a century has identified as essential six trace elements whose functions were previously unknown. In addition to the long-known deficiencies of iron and iodine, signs of deficiency for chromium, copper, zinc, and selenium have been identified in free-living populations. Four trace elements were proved to be essential for two or more animal species during the past decade alone. Marginal or severe trace element imbalances can be considered risk factors for several diseases of public health importance, but proof of cause and effect relationships will depend on a more complete understanding of basic mechanisms of action and on better analytical procedures and functional tests to determine marginal trace element status in man.