The Toxicologist - Society of Toxicology

2218 PSIDIUM GUAJAVA INHIBITS IGE-MEDIATED
ALLERGIC RESPONSES BY BLOCKING FCεRI
SIGNALING IN MAST CELLS.
J. Im 1 , E. Han 1 , J. Park 1 , J. Yang 1 , J. Seo 2 , Y. Chung 2 and H. Jeong 1 .
1 Pharmacy, Chungnam National University, Daejeon, Republic of Korea and 2 Food
Science, Korea International University, Jinju, Republic of Korea.
Psidium guajava (P. guajava) is a food and plant with antioxidant, anti-inflammatory,
and anti-allergic activities, supporting its traditional uses. However, its precise
effects remain unknown. We investigated the effects of P. guajava ethyl acetate extract
(PGEA) on allergic responses in rat mast RBL-2H3 cells. PGEA reduced
DNP-BSA (antigen)-induced release of β-hexosaminidase and histamine in IgEsensitized
mast cells. Additionally, it inhibited antigen-induced IL-4 and TNF-α
mRNA expression and protein production in IgE-sensitized mast cells. PGEA also
reduced antigen-induced COX-2 mRNA and protein expression in these cells.
Moreover, it inhibited antigen-induced activation of NF-κB and degradation of
IκB-α. To identify the mechanisms underpinning the inhibition of degranulation
and cytokine production by PGEA, we examined the activation of intracellular
FcεRI signaling molecules. PGEA suppressed antigen-induced phosphorylation of
Syk, LAT, Gab2, and PLCγ2 but not Lyn. Collectively, the anti-allergic effects of
PGEA in vitro suggest its possible therapeutic application to inflammatory allergic
diseases, in which its inhibition of inflammatory cytokine production and FcεRIdependent
signaling events in mast cells may be hugely beneficial.
2219 NOVEL PHARMACOLOGICAL ACTIONS OF NATURAL
ANTAGONISTS DERIVED FROM K. BREVIS (RED TIDE).
W. M. Abraham 1 and D. G. Baden 2 . 1 Research, Mount Sinai Medical Center,
Miami Beach, FL and 2 Marine Science, University of North Carolina Wilmington,
Wilmington, NC.
Brevenal and B-naphthoyl brevetoxin (B-Nap) are two antagonists derived from
Florida red tide organisms. We previously reported that aerosol treatment with
pMolar concentrations of these agents a) improves mucociliary clearance (MCC)
and b) prevents and reverses human neutrophil elastase (HNE)-induced slowing of
MCC, responses not seen with inhaled glucocorticosteroids. These actions suggested
that brevenal and B-Nap are potential drug candidates for the treatment of
diseases associated with MCC dysfunction. We extended our safety assessment of
these compounds by defining maximal aerosol doses that could be delivered without
causing bronchoconstriction (< 100 ug/ml ) and showing that repeat dosing
(b.i.d. 50 ug/ml for 5 days) does not cause airway hyperresponsiveness. Thus, neither
agent induces airway irritant effects at doses 50,000-fold higher than needed
to show pharmacological activity. Here we describe novel actions of both brevenal
and B-Nap, i.e. blocking histamine- and HNE-induced bronchoconstriction,
which increases their potential for drug development. Increasing concentrations of
aerosol histamine were given to sheep to generate histamine dose response curves.
Brevenal and B-Nap (20 breaths of 100 pg/ml) given 30 min before histamine
challenge reduced the histamine response by 72 and 68%, respectively. These results
compared favorably with the clinical drug clarinex (5 mg, PO) which gave
67% protection. Extending the pretreatment time to 2h before histamine challenge
gave 36% and 59% protection with brevenal and B-Nap, respectively. The same
dose of these agents given 30 min before HNE-challenge inhibited the constrictor
response by 66%. These results indicate that these naturally-derived marine products
show pharmacological activity against prominent mediators associated with
airway allergic and inflammatory responses. Their protective actions are multifaceted
and are seen at nMolar concentrations. Both characteristics are advantageous:
broad spectrum protection with a potential reduction in higher dose-induced side
effect profile.
2220 BIOACTIVATION EVALUATION OF HERBAL
INGREDIENTS.
Z. Fang, Y. Zhang, H. Ma, G. Li and L. Yang. Laboratory of Pharmaceutical
Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Scienes,
Dalian, Liaoning, China. Sponsor: P. Wells.
Elucidation of toxicological properties of herbal medicines is becoming more and
more important with the increasing application of herbal medicines for treatment
of various diseases and promotion of health. It has been widely recognized that
bioactivation of herbal components represents a critical reason for herbal toxicity
induction including direct herbal toxicity and herb-drug interaction. To date, over
20 “structural alerts” have been reported to easily undergo bioactivation and induce
toxicity. Among these toxicophores, methylenedioxyphenyl and indole groups were
476 SOT 2011 ANNUAL MEETING
often found in natural products. Therefore, the focus was given to bioactivation
evaluation of these two classes of herbal constituents in the present study.
Noscapine and rutaecarpine were selected as model compounds. In vitro chemical
trapping method was adapted. The experiment was carried out in human liver microsomes
with NADPH-generating system, reduced glutathione (GSH) and tested
compound. The adducts were detected using LC-MS/MS. Chemical inhibition
study and recombinant CYP isoforms assay were employed to identify the enzymes
involved in the formation of reactive metabolites. The results showed that the corresponding
GSH conjugate was formed, and ortho-quinone and quinone-imine
metabolites were proposed to be reactive intermediates of noscapine and rutaecarpine,
respectively. Furthermore, CYP3A4, CYP2C9 were major responsible CYP
isoforms for noscapine’s bioactivation, and CYP3A4, CYP1A2 were mainly involved
in the bioactivation of rutaecarpine. All these experiments demonstrated
that potential risk associated with herbal bioactivation might exist when these natural
products were clinically used. However, given that many other factors (e.g.
herbal complexity, variability of biological systems, etc.) might influence the explanations
of herbal bioactivation, further experiments need for the toxicity evaluation
of these natural products.
2221 CYTOTOXIC EFFECTS OF ARBUTIN IN MAMMALIAN
CELLS AFTER ACTIVATION BY HUMAN INTESTINAL
BACTERIA.
H. Kim 1 , T. Khanal 1 , H. Ha 2 , T. Jeong 2 and H. Jeong 1 . 1 Pharmacy, Chungnam
National University, Daejeon, Republic of Korea and 2 Pharmacy, Yeungnam National
University, Gyeonsgan, Republic of Korea.
Hydroquinone is present in a number of plant-derived foods such as wine, coffee,
broccoli and certain fruits, where it predominantly occurs in its glycosylated form:
Arbutin (hydroquinone-beta-D-glucopyranoside). This study was conducted to investigate
the cytotoxic responses of arbutin and its metabolites (hydroquinone) to
determine the metabolism of cytotoxic activities. Hydroquinone, arbutin metabolites,
increases strong cytotoxic effect in hepatoma cells, but not with arbutin. In
addition, hydroquinone-induced apoptosis was confirmed by apoptosis assays.
Furthermore, increased ROS generation was noted by the treatment of hydroquinone
to compare with arbutin. Following an incubation of arbutin with intestinal
bacteria for 24 hr, it was detected that arbutin was metabolized to hydroquinone.
Arbutin metabolites showed more potent cytotoxicity against mammalian
cells than arbutin control. These findings suggest that intestinal microflora may activate
the cytotoxic effect of metabolism of arbutin to hydroquinone in hepatoma
cells. [This research was supported by a grant (09172KFDA996) from Korea Food
& Drug Administration in 2010.]
2222 PREVENTION OF ADRIAMYCIN HEPATIC AND RENAL
TOXICITY IN MALE BALB/C MICE BY A NUTRIENT
MIXTURE.
M. Roomi, N. W. Roomi, M. Rath and A. Niedzwiecki. Dr. Rath Research
Institute, Santa Clara, CA.
Introduction: Adriamycin (ADR) or doxorubicin is an antineoplastic antibiotic
used in cancer therapy. However, several studies suggest that its increasing acute
and chronic use is associated with toxicity of vital organs. A unique nutrient mixture
(NM) consisting of lysine, proline, ascorbic acid and green tea extract has previously
been shown to exhibit a broad spectrum of pharmacological, therapeutic,
cardiovascular and chemopreventive properties. Objective: This study was undertaken
to determine whether NM is useful in prevention of ADR-induced hepatic
and nephric toxicity. Materials and Methods: Six week-old male BALB/c mice were
divided into four groups (A-D) of six animals each. Groups A and C were fed a regular
diet for three weeks, while groups B and D were fed a diet supplemented with
1% NM during that period. After three weeks, mice in groups C and D received
ADR 20 mg/kg body weight i.p., and those in groups A and B received saline alone.
All animals were sacrificed after 24 hrs, blood was withdrawn by cardiac puncture,
serum collected for clinical chemistry, and livers, kidneys and hearts were excised
for histology. Results: Administration of ADR to group C resulted in marked increase
in ALT, AST and gamma-GT levels, whereas in group D (NM diet) the
serum ALT, AST and gamma-GT activities were not affected, but were comparable
to the levels of the control group A and NM-fed group B. Administration of ADR
also resulted in significantly increased levels of serum markers for kidney (BUN,
creatinine and uric acid) in group C. In contrast, animals in group D exhibited similar
levels to those in groups A and B. The histological changes will be discussed in
view of their blood chemistry. Conclusions: The results indicate that NM has potential
to protect against ADR-induced hepatic and nephric damage.