BIOLOGICALLY ACTIVE COMPOUNDS FROM
PLANTS: 40 YEARS OF SEARCHING FOR A
SCIENTIFIC POT OF GOLD
Second Professor Frank Fish
Memorial Award Lecture
School of Pharmacy
University College London
October 9, 2013
Prof. A. Douglas Kinghorn
Professor and Jack L. Beal Chair
College of Pharmacy
The Ohio State University
Professor Frank Fish,
OBE
(1924-2011)
B. Pharm (London), 1946
Ph.D. (Glasgow), 1955
Established the M.Sc.
Course in Forensic
Science at the University
of Strathclyde in 1966
Dean, School of
Pharmaceutical
Sciences, University of
Strathclyde, 1977-1978
Dean, School of
Pharmacy, University of
London, 1978-1988
OUTLINE OF PRESENTATION

Continued Importance of Natural ProductDerived Drugs in the 21st Century.
The Crucial Role of Mentorship in Career
Development – a Personal Perspective.
Examples of Promising Lead Compounds from
Tropical Plants:






Hernandulcin, a Highly Sweet Sesquiterpenoid
Silvestrol, a Potential Agent to Combat B-Cell
Malignancies
“Active
Constituents”
of
Botanical
Dietary
Supplements, as Exemplified by 2-Methoxy-2,4,6trihydroxyanthraquinone from Noni and -Mangostin
from Mangosteen
Conclusions.
CONTINUED IMPORTANCE OF
NATURAL PRODUCT-DERIVED
DRUGS IN THE 21ST CENTURY
NUMBERS OF ORGANISMS FOR DRUG
DISCOVERY
Eubacteria (bacteria), cyanobacteria (blue-green algae)
Archaea (halobacteria, cyanogens)
Protoctista (e.g., protozoa, diatoms, “algae”,
algae” and “green algae”)
4,000a
Unknown
80,000
including “red
Plantae (mosses and liverworts, ferns, seed plants)b
Fungi (e.g., molds, lichens, yeasts, mushrooms)c
270,000
72,000
Animalia (e.g., mesozoa, sponges, jellyfish, corals, flatworms, 1,320,000
roundworms, sea urchins, mollusks, segmented worms,
arthropods, insects, fish, amphibians, birds, mammals)d-f
a
b
c
d
e
f
Figures are species described taxonomically to date in each group.
Plants are the second largest group of classified organisms, representing 15% of the known biodiversity.
Only a relatively small proportion (5%) of the estimated 1.5 m fungi have been classified taxonomically to date.
The largest numbers of organisms are the arthropods, inclusive of insects (ca. 950,000 species).
Of the 28 major animal phyla, 26 are found in a marine environment.
Over 200,000 species of invertebrate animals and algal species occur in the sea.
(Tan et al., Curr. Drug Targets 7, 265, 2006)
NUMBER OF DRUGS APPROVED IN
THE UNITED STATES (1981 TO 2007)
(Li and Vederas, Science 325, 161, 2009)
NATURAL PRODUCT-DERIVED DRUGS
INTRODUCED IN THE U.S. (2000-2008)
Source Organism Type
Terrestrial Plants
(apomorphine HCl, arteether, dronabinol/cannabidiol (mixture), galanthamine
HBr, lisdexamfetamine, methylnatrexone Br, nitisinone, tiotropium Br)
Terrestrial Microorganisms
(amrubicin HCl, anidulafungin, biapenem, caspofungin acetate, cefditoren
pivoxil, ceftobiprole medocaril, daptomycin, doripenem, ertapenem, everolimus,
fumagillin, gentumazumab ozogamicin, ixabepilone, micafungin Na, miglustat,
mycophenolate Na, pimecrolimus, pitavastatin, retapamulin, rosuvastatin Ca,
telithromycin, temsirolimus, tigecycline, zotarolimus)
Number
8
24
Marine Organisms
(trabectidin, ziconotide)
2
Terrestrial Animals
(bivalirudin; exenatide; synthetic versions of natural forms)
2
[Chin et al., AAPS J., 8 (2), E239-E253, (Article 28), 2006; http://www.aapsj.org; Butler, in
Natural Product Chemistry for Drug Discovery, eds. A.D. Buss and M.S. Butler, RSC:
Cambridge, U.K., 2010; p. 321]
IXABEPILONE (IXEMPRATM)
Ixabepilone R = NH
Epothilone B R = O
https://www.genetik.uni-bielefeld.de/GenoMik/cluster6.html
http://www.nature.com/nrc/journal/v2/n2/slideshow/nrc723_F2.html
 Lead compound was
epothilone B isolated
from
Sorangium
cellulosum
(a
myxobacterium).
 Anticancer
agent
(refractory
breast
cancer) (B-MS, 2007).
 Interacts with tubulin.
ECTEINASCIDIN 743: AN ANTICANCER
AGENT FROM A MARINE TUNICATE
Ecteinascidia turbinata
Ecteinascidin 743; ET-743;
trabectedin, Yondelis® [Soft
tissue sarcoma (Europe)]
www.pharmamar.com
http://www.teridanielsbooks.com/States/reptile_lizard_gila_monster.jpg
GILA MONSTER (HELODERMA SUSPECTUM)
SOURCE OF EXENATIDE – ANTIDIABETIC AGENT
PLANT NATURAL PRODUCTS AND DERIVATIVES APPROVED BY THE
U.S. FDA FROM JANUARY 2001-FEBRUARY 2013a
Year
Approved
2001
2002
2003
2004
2004
2004
2005
Generic Name
Natural Lead Compound
Galantamineb
Nitisinoneb
Miglustatb
Tiotropiumb bromide
Trospiumb chloride
Solifenacinb
Paclitaxel (protein-bound)
Galanthamine
Leptospermone
1-Deoxynojirimycin
Atropine
Atropine
Quinine
Paclitaxel (taxol)
Trade
Name
Razadyne
Orfadin
Zavesca
Spiriva
Sanctura
VESIcare
Abraxane
2006
2006d
2008
2008
2009
2009
2009
2010
2010
Green tea phenols
Δ9-Tetrahydrocannabinol
Morphine
Emetine
Artemesinin
Colchicine
Capsaicin
Paclitaxel (taxol)
Morphine and quinidine
Veregen
Cesamet
Relistor
Xenazine
Coartem
Colcrys
Qutenza
Jevtana
Nuedexta
2011
Sinecatechinsb,c
Nabiloneb
Methylnaltrexoneb bromide
Tetrabenazineb
Artemetherb and lumefantrine
Colchicined
Capsaicin
Cabazitaxelb
Dextromethorphan and
quinidine
Ioflupane I-123b
Cocaine
Datscan
2011
Gabapentin enacarbilb
-Aminobutyric acid (GABA)
Horizant
Brain imaging with
syndromes
Restless leg syndrome
Ingenol-3-angelate
Picato
Actinic keratosis
Ephedrine
Belviq
Obesity
mebutateb
Indication
Dementia associated with Alzheimer's disease
Hereditary tyrosinemia type 1
Type 1 Gaucher disease
COPD and exacerbation of COPD
Overactive bladder
Overactive bladder
Breast cancer (also approved for lung cancer in
2012 )
Genital and perianal warts
Chemotherapy-induced nausea
Opioid-induced constipation
Huntington's-associated chorea
Malaria
Gout
Postherpetic neuralgia
Hormone-refractory metastatic prostate cancer
Pseudobulbar Affect
suspected
Parkinsonian
2012
Ingenol
2012
Lorcaserinb
2012
Icosapent ethyl
Eicosapentaenoic acid (EPA) Vascepa
Hypertriglyceridemia
2012
Omacetaxine mepesuccinateb
Homoharringtonine
Synribo
Chronic myeloid leukemia
2012
Crofelemerb,c
Fulyzaq
HIV/AIDS anti-retroviral-associated diarrhea
2013
Trastuzumab emtansine
(antibody-conjugate)
Ospemifeneb
Croton lechleri oligomeric
proanthocyanidin
Maytansine
Kadcyla
Breast cancer
Phytoestrogens
Osphena
Menopause-associated dyspareunia
2013
a
hydrochloride
Information taken from Drugs@FDA (http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm) and Kinghorn, et al. J.
Nat. Prod. 74, 1539, 2011 b New molecular entity. c Approved as a mixture of compounds as a “botanical drug”. d Originally
approved in combination therapy in 1985; newly approved as a monotherapy.
INGENOL MEBUTATE FOR THE TREATMENT
OF ACTINIC KERATOSIS
Euphorbia peplus (Euphorbiaceae)
Ingenol mebutate
(Ingenol-3-angelate)
( Picato )
http://www.discoverlife.org/mp/20q?search=Euphorbia+peplus&mobile=iPhone
http://luirig.altervista.org/flora/taxa/index1.php?scientific-name=euphorbia+peplus
Approved by U.S. FDA in 2012 for the treatment of actinic keratosis, a precursor
to sun-related squamous cell carcinoma (used as a topical gel) (Lebwohl et al., N.
Engl. J. Med. 366, 1010, 2012; Mason, Pharm. J. 290, 141, 2013).
This compound was isolated from Euphorbia peplus (Hohmann et al., Planta
Med. 66, 291, 2000). New 14-step synthesis: Jorgensen et al., Science 341, 878,
2013.
DEFINITION OF A “BOTANICAL
DRUG PRODUCT”



In June 2004, the U.S. FDA issued the publication
“Guidance for Industry. Botanical Drug Products”
(http://www.fda.gov/cder/guidance/index.htm).
A “botanical drug product” is defined as containing as
ingredients vegetable materials, which may include plant
materials, algae, macroscopic fungi, or combinations
thereof, for use as a drug. It may be prepared, for example,
as a solution (e.g., tea), powder, tablet, capsule, elixir,
topical agent, or injectable.
Excluded are: fermentation products, highly purified or
chemically modified botanical substances, genetically
modified plants, allergenic extracts, and vaccines that
contain botanical ingredients.
(J. Dou, U.S. FDA, CDER)
OVERVIEW OF NDA PROCESS OF
FDA FOR “BOTANICAL DRUGS”







Purification to single active molecules is not required,
although
strict
documentation
of
“chemistry,
manufacturing, and controls” (CMC) must be carried
out.
Identification of “active principles” is not essential.
The same requirements for safety assurance and clinical
efficacy as for synthetic drugs are needed for NDA
approval.
Purification to single active molecules is not required.
The same levels of safety requirements and clinical
efficacy as non-botanical drugs are needed for NDA
approval.
Nearly 500 IND/pre-IND applications for botanical drugs
have been submitted to CDER, FDA between 1999-2012.
Most of these are in Phase 2, with a few in Phase 3.
(J. Dou, U.S. FDA, CDER)
SINECATECHINS FROM GREEN TEA (CAMELLIA
SINENSIS) AS THE FIRST “BOTANICAL DRUG”



Green tea contains mixtures of a sub-type of flavonoids (flavans)
known as “catechins”, which are esterified with a small phenolic
acid, gallic acid.
Epigallocatechin gallate (EGCG), the major flavonoid ester in
green tea, is one of the most highly studied natural product
molecules in the biomedical literature.
A mixture of green tea catechins (“sinecatechins”; Veregen)
was the first “botanical drug” approved by the U.S. FDA in 2006
(used topically to treat venereal and perianal warts) (Chen et al.,
Nature Biotechnol. 26, 1077, 2008).
CROFELEMER, THE FIRST FDA-APPROVED
“BOTANICAL DRUG” TO BE TAKEN ORALLY
J. Dou, CDER, FDA



Crofelemer is a complex
mixture of proanthocyanidins
(literally
thousands
of
compounds co-occur).
The plant of origin is called
“Dragon’s Blood”.
Crofelemer (Fulyzaq) was
approved as a “botanical drug”
by the USA FDA in 2012 as an
oral antidiarrheal agent.
THE CRUCIAL ROLE OF MENTORSHIP
IN CAREER DEVELOPMENT – A
PERSONAL PERSPECTIVE
B.PHARM. (SPECIAL IN
PHARMACOGNOSY) AT BRADFORD
(1966-1969)
Dr. Peter
A. Linley
Dr. Keith J.
Harkiss
served as
tutor and
supervised
a thee-part
undergraduate
thesis
MASTER’S IN FORENSIC SCIENCE AT
STRATHCLYDE (1969-1970)
Prof. Frank Fish, Coordinator of
the M.Sc. Course in Forensic
Science
(Thesis performed under the
supervision of Mr. Peter F.
Nelson)
TEACHING FELLOWSHIP AND PH.D.
STUDENTSHIP AT THE SQUARE (1971-1975)
Late
Prof.
Evans,
Supervisor
Fred
Ph.D.
(Dissertation carried
out on the skin-irritant
diterpene esters of
Euphorbia species)
SENIOR PHARMACOGNOSY ACADEMIC STAFF
AT “BRUNSWICK SQUARE” (1970s-1990s)
LATE PROF. JAMES W.
FAIRBAIRN
(ANTHRAQUINONES;
OPIUM POPPY;
CANNABIS SATIVA)
EMER. PROF.
J. DAVID
PHILLIPSON
(ALKALOIDS;
ANTIPROTOZOALS; TISSUE
CULTURE)
LATE PROF.
FRED J. EVANS
(PHORBOL ESTERS;
CANNABIS SATIVA;
PH.D.
SUPERVISOR)
DR. MARGARET F.
ROBERTS
(ALKALOID
BIOSYNTHESIS;
PAPAVER
ALKALOIDS)
U.K. PHARMACOGNOSISTS AT A
CELEBRATION IN THE LATE 1970S
Photograph Provided by Prof. J. David Phillipson
PRESENT PHARMACOGNOSY LEADERS AT
“BRUNSWICK SQUARE”
PROF. MICHAEL
HEINRICH
(ETHNOBOTANY,
PHYTOTHERAPY;
PHARMACEUTICAL
BIOLOGY)
PROF. SIMON
GIBBONS (ANTIINFECTIVE AGENTS
FROM PLANTS;
DRUGS OF ABUSE)
M.SC. DEGREE IN PHARMACOGNOSY
AT UCL SCHOOL OF PHARMACY
Dr. Jose Prieto-Garcia
Programme Director
Prof. Simon Gibbons
Deputy Programme Director
Invited Guest Lecturers from outside UCL include Dr. Colin Wright (University
of Bradford), Prof. Peter Houghton (King’s College London), Prof. Monique
Simmonds (RBC, Kew), and Prof. Elizabeth Williamson (University of Reading)
SABBATICAL OF PROFESSOR DAVE PHILLIPSON AT
THE OHIO STATE UNIVERSITY IN THE LATE 1960s
Late Professor Jack L.
Beal
The Ohio State
University
Emeritus Professor
Raymond W. Doskotch
The Ohio State
University
A NIGHT ON THE TOWN WITH PROFESSOR
NORMAN R. FARNSWORTH AT “TRADER VICS”
Photograph Provided by Prof. Norman R. Farnsworth
DEPARTMENT OF PHARMAGNOSY, UNIVERSITY OF
MISSISSIPPI, 1975 (HEAD: NORMAN J. DOORENBOS)
THE ARROWS SHOW PROF. DOORENBOS AND
THE FUTURE MRS. KINGHORN
Late Dr. Norman R. Farnsworth
University of Illinois at Chicago
1930-2011
Slide Provided by Professor J. David Phillipson
DRS. MONROE WALL AND MANSUKH WANI –
DISCOVERERS OF TAXOL AND CAMPOTHECIN
(Photograph by Jimmy W. Crawford, RTI)
EXAMPLES OF PROMISING
LEAD COMPOUNDS FROM
TROPICAL PLANTS
EXAMPLES OF LEAD COMPOUNDS OF
INTEREST FROM TROPICAL PLANTS
Abrusoside A
(Chem. Commun., 1989)
α-Mangostin
(Nutr. Res., 2012)
Pervilleine A
(Cancer Res., 2001)
Betulinic acid
(Nature Med., 1995)
2-Methoxy-1,3,6anthraquinone
(J. Nat. Prod., 2005)
trans-Resveratrol
(Science, 1997)
Hernandulcin
(Science, 1985)
Pentalinonsterol
(Phytochemistry, 2012)
Silvestrol
(J. Org. Chem., 2004)
TASTE AND THE TONGUE



Humans have ca. 10,000 taste buds with each taste bud
containing 50-100 taste receptor cells.
The popular taste map of the tongue taste is based on faulty
interpretation of a 1901 paper, in fact taste buds on many
areas of the tongue can detect different tastes.
Bitterness has a much lower taste threshold than sweetness
due to the biological imperative to select for nutritious foods
while avoiding toxins.
Image from Lindeman
Image from www.rickbakas.com
Lindeman, B. Nature Med., 1999, 5, 381-382.
Scott, K. Neuron, 2005, 48, 455-464
COMPARISON OF THE SWEETNESS INTENSITIES OF “LOWCALORIC” AND “REDUCED-CALORIE” NATURAL PRODUCT
SWEETENERS (ALL OF HIGHER PLANT ORIGIN)
“Low-Caloric” (“High Potency Sweeteners”)
Compound
Sweetness Intensity1
Glycyrrhizin
50-100
Lactitol
0.4
Stevioside
150-250
Isomalt
0.45-0.65
Perillartine2
370
Sorbitol
0.6
Phyllodulcin
400
Mannitol
0.7
Compound
Sweetness Intensity1
Rebaudioside A
200-300
Maltitol
0.9
Mogroside V
250-450
Xylitol
1.0
High-Fructose
Corn Syrup
(90%)
1.0
MGGR2
941
Hernandulcin
1500
Monellin
Neohesperidin
dihydrochalcone2
Thaumatin
1
“Reduced-Calorie” (“Bulk Sweeteners”)
1500-2000
1800
2000-3000
Relative to sucrose (=1). Sweetness intensity varies with concentration being tasted.
2Semi-synthetic compound.
HERNANDULCIN, A HIGHLY SWEET COMPOUND
FROM LIPPIA DULCIS (VERBENACEAE)




In Mexico, L. dulcis is used as an
emmenagogue, to induce menses, as an
abortifacient, and to treat coughs and
stomachache.
The plant was purchased in bulk at a
marketplace in Mexico City, and collected
in the field at Tlayacapan, Morelos,
Mexico in May-June, 1982 by then
graduate student Cesar M. Compadre.
The compound was determined as a
novel bisabolane sesquiterpene by
spectroscopic methods.
The structure was checked by synthesis
in
the
(±)-form
by
directed-aldol
condensation of the ketones 3-methyl-2cyclohexen-1-one (I) and 6-methyl-5hepten-2-one (II).
(Compadre et al., Science 227, 417, 1985)
Prof. Cesar M. Compadre
IDEAL PROPERTIES OF A NONCALORIC AND
NONCARIOGENIC SWEETENER FOR POTENTIAL
USE AS A SUCROSE SUBSTITUTE

Highly sweet, odorless, colorless, with taste
characteristics similar to sucrose.

Water soluble, stable.

No toxicity nor cariogenicity, from either the
parent substance or its metabolites.

Easy to synthesize or to obtain by cultivation.

Should fit existing techniques for the application
of sweeteners.

Economically
competitive
approved sweeteners.
with
currently
(Hough et al., Eds. In Developments in Sweeteners – 1;
Applied Science Publishers, London, 1979; p. v)
STRUCTURAL CHARACTERIZATION OF
SILVESTROL FROM AGLAIA FOVEOLATA
Silvestrol
X-ray Structure by
Drs.
Bernard
Santarsiero and
Andrew Mesecar
(UIC)
Drs. Bang Yeon Hwang and Baoning Su
(Hwang et al., J. Org. Chem. 69, 3350, 2004;
ibid., 69, 6156)
COLLABORATIVE PROJECTS ON NATURAL
PRODUCT ANTICANCER DRUG DISCOVERY
National Cooperative Drug Discovery Group (NCDDG) Grant
(U19 CA52956)
Program Project Grant
(P01 CA125066)
Collaboration between:
The Ohio State University, Columbus, OH;
University of Illinois at Chicago, Chicago, IL;
University of North Carolina at Greensboro, NC;
Mycosynthetix Inc., NC;
Bristol-Myers Squibb, Princeton, NJ.
Funded by the United States National Cancer Institute, NIH (1990-2006;
2007-2013)
[Most recent review: Kinghorn et al., Pure Appl. Chem. 81, 1051, 2009]
NCDDG GROUP AT THE MEDICINAL PLANT GARDEN,
UNIVERSITY OF ILLINOIS AT CHICAGO IN 2003
SHOWS LEFT TO RIGHT (UIC UNLESS STATED) MARCY BALUNAS, GEOFF
CORDELL, STEVE SWANSON, DOEL SOEJARTO, YALI FU (NCI), NORM
FARNSWORTH, GORDON CRAGG (NCI), MANSUKH WANI (RTI), DOUG
KINGHORN, WILL JONES, NICK OBERLIES (RTI), TATIANA LOBO, AIKO ITO,
YINGMEI TAN. GHEE TAN, BANG YEON HWANG, AND FAUSTO RIVERO-CRUZ
IN VITRO CYTOTOXICITY OF SILVESTROL
Compound
Silvestrol
Methyl
rocaglateb
Paclitaxelc
Camptothecinc
a
b
c
Lu1
1.2
163
2.3
28.7
Cell linea
LNCaP
MCF-7
1.5
1.5
325
Not
determined
4.7
0.7
28.7
28.7
HUVEC
4.6
203
105.5
258.6
ED50 values (nM) - Lu1 = human lung cancer; LNCaP
= hormone-dependent human prostate cancer; MCF-7
= human breast cancer; HUVEC = human umbilical
vein endothelial cells.
Isolated in our previous work (Rivero-Cruz et al., J.
Nat. Prod., 67, 343, 2004).
Used as positive control.
(Hwang et al., J. Org. Chem. 69, 3350, 2004)
EFFECT OF SILVESTROL IN THE IN VIVO HOLLOW
FIBER TEST AND IN THE MURINE P-388 LEUKEMIA
MODEL
Hollow fiber:
Murine P-388 leukemia:
 Active at maximum tolerated dose of
2.5 mg/kg/inj, given by intraperitoneal
injection daily for five consecutive
days (qd5) in ip P388 model.
 Achieved maximum lifespan increase
corresponding to T/C of 150%.
 Inactive (T/C = 100%) in iv P388 leukemia
model when administered by either the iv
or ip route using a daily times five schedule
(qd5).
 Active (T/C = 129%) in same tumor model
when injected iv on a twice-daily schedule
(2qd5) using the same cumulative dose (2
mg/kg/day).
(Hwang et al., J. Org. Chem. 69,
3350, 2004)
% Live Cells Relative to Untreated
EFFECTS OF SILVESTROL ON B AND T CELLS
IN WHOLE BLOOD FROM CHRONIC
LYMPHOCYTIC LEUKEMIA (CLL) PATIENTS
B Cells
T Cells
120
120
100
100
80
80
60
60
40
40
20
20
0
0
24
48
Incubation Time (hours)
72
80 nM Silvestrol
0
0
24
48
Incubation Time (hours)
1 µM 2-F-ara A
(Lucas et al., Blood 113, 4656, 2009)
72
SILVESTROL SIGNIFICANTLY IMPROVED
SURVIVAL IN AN ACUTE LYMPHOBLASTIC
LEUKEMIA (ALL) XENOGRAFT MOUSE MODEL
100
Median survival
difference P = 0.002
% Survival
80
Control (N=13)
60
Silvestrol (N=14)
40
1.5 mg/kg i.p. M, W, F; started 1
wk post-engraftment
20
Treatment stopped
0
0
5
10
15
20
25
30
35
40
45
85
Days Post Engraftment
The remaining three mice appeared normal 12+ weeks postengraftment, 6 weeks after the last treatment.
(Lucas et al., Blood 113, 4656, 2009)
SILVESTROL: WORK PERFORMED BY OTHER GROUPS


Silvestrol was totally synthesized by two groups in 2007, the
groups of Porco (Boston University) (Gerard et al., Angew.
Chem. Int. Ed., 46, 7831, 2007) and Rizzacasa (University of
Melbourne) (El Sous et al., ibid., 46, 7835, 2007).
Pelletier and co-workers have shown that silvestrol is a
translation inhibitor by targeting eukaryotic initiation factor
(eIF) 4A (Cencic et al., PLoS ONE 4(4), e5223, 2009).
The figure shows the translation
initiation
complex
and
known
inhibitors (Lucas et al., Curr. Drug
Targets 11, 811, 2010); based in part
on Cencic et al., 2009, as cited
above).
In
very
recent
work,
using
biotinylated
5-epi-silvestrol,
a
specific interaction was shown with
eIF4AI and eIF4AII (Chambers et al.,
Org. Lett. 15, 1406, 2013).
SILVESTROL: A POTENTIAL NEW THERAPEUTIC
AGENT FOR B-CELL MALIGNANCIES



At The Ohio State University, silvestrol has shown promising in vivo
activity in models of acute lymphoblastic leukemia, acute myeloid
leukemia, EBV-driven lymphoma, and mantle cell lymphoma (Lucas et
al., Blood 113, 4656, 2009; Alinari et al., Clin. Cancer Res. 18, 4600, 2012;
Alahkar et al., J. Hematol. Oncol. 6, 21, 2013).
Silvestrol was selected for preclinical development by NCI through the
DDG IIA mechanism in 2007, and is now in the NCI NExT program having
been subjected to additional peer and program review in August 2013.
The mechanism of antileukemic action is being further investigated
through Project 5 of a NCI/NIH SPORE (P50) award (J. C. Byrd, PI) (M.R.
Grever, D.M. Lucas) (2009-2014).
EFFECTS OF SILVESTROL ANALOGUES ON GROWTH
INHIBITORY ACTIVITY OF HUMAN CANCER CELLS
The presence of a 1,4-dioxanyloxy moiety at C-6
enhances activity dramatically
The cyclopenta[b]benzofuran moiety
and other aromatic units confer basic
cytotoxicity to this compound class
Esterification or change
in configuration of the
hydroxy group at C-1
diminishes cytotoxicity
Esterification of the hydroxy
groups at C-5''' and C-6'''
decreases resultant cytotoxicity
Inversion of configuration at C-2'''
reduces cytotoxicity much more
than when inverted at C-5'''
Methyl
ester
group
required for potency
Absence of OCH3 at C-4' diminishes
resultant cytotoxicity slightly
The natural product silvestrol is the most potent of ca. 15 close analogues investigated
(Hwang et al., J. Org. Chem. 69, 3350, 2004; Adams et al., J. Am. Chem. Soc. 131, 1607, 2009; Pan et
al., J. Nat. Prod. 73, 1873, 2010; Woodard IV et al., Unpublished results)
is
AGREEMENT FOR DEVELOPMENT OF SILVESTROL
FOR POTENTIAL TREATMENT OF B-CELL MALIGNANCIES
In June 2012, after protracted
negotiations, an agreement was
signed to jointly develop silvestrol
between The Ohio State University
and the Sarawak Biodiversity Center,
with
the
immediate
goal
of
conducting preclinical toxicology.
The U.S. NCI will be involved
through the NExT program.
This slide shows the two other
faculty participants in this work at
Ohio State, Drs. Michael Grever (top
left) and David Lucas (top right), and
Dr. Rita Manurung, Chief Operating
Officer, Sarawak Biodiversity Center,
Kuching,
Sarawak,
Malaysia
(bottom). Silvestrol will be sourced
from Aglaia stellatopilosa grown in
Sarawak.
DIETARY HEALTH SUPPLEMENT AND
EDUCATION ACT (DSHEA) (1994)






Defined terms “dietary supplement” (including
herbal remedies) and “dietary ingredient”.
These are taken orally and may be used as in forms
such as tablets, capsules, soft gels, gel liquids, and
powders.
Exempted dietary supplements marketed before
October 15, 1994 from new dietary ingredient (NDI)
review.
Established
requirements
for
new
dietary
ingredients.
A dietary supplement may be declared as a hazard
to public health or safety.
“Structure and function” claims may be made, but
most labels have a disclaimer about health benefits.
NONI AS A DIETARY SUPPLEMENT
Marketed in the U.S. by
several companies. Noni
juice is available in many
retail outlets, including
supermarkets,
healthfood
stores,
and
pharmacies.
Tahitian and Hawaiian
noni juice are both
available.
 Marketing
toward
layman primarily based
on the likely fictitious
alkaloid, “xeronine”.
(Heinecke, Pac. Trop. Bot. Gard.
Bull. 10, 15, 1985)
NONI (MORINDA CITRIFOLIA)
(RUBIACEAE)
Occurs
in
tropical
and
subtropical regions.

All parts (fruit, leaf, bark,
flower, and seed) have been
utilized medicinally.

Roots and bark are used as a
dye.

In
initial
isolation
work
performed at The Ohio State
University,
a
lignan
(americanin
A)
and
a
flavonoid
glycoside
(narcissoside)
were
isolated
as
antioxidant
constituents of noni fruits.

No trace of xeronine was
found!
(Su et al., J. Nat. Prod. 68, 592,
2005).
http://www.nps.gov/kaho/KAHOckLs/KAHOplnt/noni.htm

Dr. Alison Pawlus
(Review: Pawlus and Kinghorn, J. Pharm. Pharmacol. 59, 1587, 2007)
QUINONE REDUCTASE-INDUCING ACTIVITY OF
ISOLATED CONSTITUENTS OF NONI FRUITS
Compound
CDa, M (g/mL)
IC50b, M (g/mL)
CIc
1d
0.009 (0.0027)
>69.9 (>20)
>7770
2
1.67 (0.52)
>66.6 (>20)
>39.9
L-sulforaphane*
0.34 (0.061)
9.77 (1.73)
28.7
aCD
= Concentration required to double quinone reductase induction. bIC50 = Concentration
for 50% inhibition of cell viability. cCI = Chemopreventive Index. d Only 2 mg of 1,3,6trihydroxy-2-methoxyanthraquinone (1) isolated from ca. 9 kg dried noni fruits. * = Control.
1 (new, 2-methoxy-1,3,6,trihydroxyanthraquinone)
2
(Pawlus et al., J. Nat. Prod. 68, 1720, 2005)
INHIBITORY EFFECT OF NONI FRUITS
ON RAT ESOPHAGEAL TUMORIGENESIS




Male F344 rats were fed a diet of 5% w/w dried
powdered fruits of M. citrifolia (noni), and six other
dried fruits, including black raspberry (Rubus
occidentalis), in a comparison study.
The
standard
carcinogen,
NMBA
(Nnitrosomethylbenzylamine was used to treat rats for
five weeks, and the experiment was terminated after
35 weeks.
All seven fruits had similar effects on reducing
esophageal tumor incidence, size, and multiplicity,
and also reduced the levels of two serum cytokines.
Noni fruits have lower levels of anthocyanins and
ellagitannins than black raspberries.
(Stoner et al., Pharm. Res. 27, 1138, 2010)
GARCINIA MANGOSTANA (MANGOSTEEN)
(CLUSIACEAE)

The tropical fruit Garcinia
mangostana
L.
(Clusiaceae;
Mangosteen), has become a
major
botanical
dietary
supplement in the U.S.

Mangosteen extracts and/or their
purified xanthone constituents,
such as
-mangostin, have
antioxidant and e.g., putative
anti-inflammatory
and
antimicrobial activities.

In initial collaborative work with
Dr.
Bill
Keller,
several
mangosteen xanthones were
found to be potent antioxidants
(Jung et al., J. Agric. Food
Chem., 54, 2077, 2006).
DR. WILLIAM J.
KELLER
NATURE’S SUNSHINE
PRODUCTS, INC.
XANTHONES ISOLATED FROM THE PERICARP OF MANGOSTEEN
PROFILE OF XANTHONE CONTENT IN THE
MANGOSTEEN JUICE USED IN THE STUDY
 When analyzed by
HPLC,
the
100%
mangosteen
juice
used in the study
provided 5.3 + 0.1 mM
total xanthones, with
-mangostin being the
most
abundant
(59.9%), as indicated
in the table opposite.
-Mangostin
Xanthone
Content
in juice
(µM)
Percentage of
total xanthones
identified (%)
garcinone C
291 + 11.2
5.5
garcinone D
520 + 10.9
10.2
garcinone E
239 + 18.5
5.1
-mangostin
3190 + 123
59.9
β-mangostin
121 + 9.3
2.3
-mangostin
356 + 4.3
6.5
8-deoxygartanin
176 + 4.5
3.1
gartanin
157 + 6.9
2.8
tovophillin B
50 + 2.9
1.1
9-hydroxycalabaxanthone
193 + 7.4
3.6
Total
5290 + 166
100
Values are means + SD; n = 5 independent replicates
(Chitchumroonchokchai et al., J. Nutr. 142, 675, 2012)
DETERMINATION OF BIOAVAILABILITY IN HUMANS
OF XANTHONES FROM MANGOSTEEN JUICE
 The bioavailability of mangosteen xanthones using
human subjects is of interest, since milligram amounts
are ingested on a daily basis.
 In a preliminary study, Kondo et al. administered ca. 60
mL of a supplement (mangosteen; aloe vera; green tea;
multivitamins) to 20 fasted healthy human volunteers,
and it was concluded that -mangostin is bioavailable
(observed Cmax at tmax of ca. 1 hour) (Kondo et al. J. Agric.
Food Chem., 57, 8788, 2009).
 In a study carried out at The Ohio State University, the
bioavailability of xanthones was investigated in ten
healthy adults (five females; five males), who consumed
a single dose of 100% mangosteen juice along with a
typical fast-food (high-fat) breakfast, which was
supplemented with canola oil and soybean oil
(Chitchumroonchokchai et al. J. Nutr., 142, 675, 2012).
EFFECT OF DIETARY α-MANGOSTIN IN A MURINE
HT-29 COLON CANCER CELL XENOGRAFT MODEL
A
90
1200
a
1000
Tumor mass (mg)
80
b
70
60
50
40
30
20
Tumor mass (mg)
100
B
a
800
b
600
Values
are
means + SD; n =
12 and 6 mice
for panels A and
B, respectively
400
200
10
0
AIN-93G
AIN-93G
+ α-MG
0
AIN-93G
AIN-93G
+ α-MG
 Balb/c nu/nu mice were fed either the control diet AIN-93G or the control diet with
-mangostin (-MG; 900 mg/kg). After one week of acclimation to diet, mice were
injected sc with HT-29 cells, and then fed the same diets.
 After two weeks (panel A) or four weeks (panel B) from the initial injection of HT29 cells, the tumor masses were 27% and 41% less, respectively, in mice fed the
diet with -mangostin compared to those fed the control diet.
 Xanthones and their metabolites were found in the serum, liver, and feces.
 This work was carried out in collaboration with Professors Mark Failla and Steve
Clinton at The Ohio State University.
(Chitchumroonchokchai et al., Mol. Nutr. Food Res. 57, 203, 2013)
CONCLUSIONS: COLLABORATIVE APPROACH
TO THE DISCOVERY OF ANTICANCER AGENTS
FROM TROPICAL PLANTS
 Tropical plants are more biodiverse than
temperate plants, and thus hold the potential
of offering greater chemical diversity for
anticancer drug discovery.
 Plant collections for drug discovery must
cover the source country in terms of
intellectual property agreements.
 Efforts to harness plant compounds as
potential cancer chemotherapeutic agents
require a multidisciplinary approach with open
and frequent communications.
Photograph by Jon Gladden (April 2013)
Shown (left to right) are Tony Gromovsky, Ben Naman, Lynette Bueno, Dr. Heebyung
Chai, Dr. Li Pan, Ms. Anecie Benatrahina, Dr. Patrick Still, and Dr. Yulin Ren
Support was obtained from NIH grants N01-DE-02425, R03-07560; R01-DE08937, U19 CA52956, and P01 CA125066 and faculty start-up funding from the
Molecular Carcinogenesis and Chemoprevention Program of the OSUCCC.
Many faculty, visiting scholars, postdoctorals, and graduate students at the
University of Illinois at Chicago and The Ohio State University are thanked for
very their kind collaboration.
This is a long-running
and well-respected
book series that was
established in 1938 by
Laszlo Zechmeister.
The series has
featured contributions
by nine Nobel
laureates. The
chapters refer to the
origin, distribution,
chemistry, synthesis,
biochemistry,
functions, and uses of
naturally occurring
substances, ranging
from small molecules
to biopolymers.
College of Pharmacy and
OSU Comprehensive Cancer Center