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Medicinal Uses of Chlorophyll: A Critical Overview
V.K. Mishra1, R.K. Bacheti2 and Azamal Husen3*
1Department of Biotechnology, Doon (P.G.) Paramedical College, Dehra Dun-248001, India
2Department of Chemistry, Graphic Era University, Dehra Dun-248001, India
3*Department of Biology, Faculty of Natural and Computational Sciences, University of Gondar
P.O. Box 196, Gondar, Ethiopia
(*Email: adroot92@yahoo.co.in)
Abstract
Reports on traditional medicinal uses of chlorophyll in alternative forms of medicine are known since
ages. Now-a-days chlorophyll has been used in the field of medicine as remedy and diagnostics.
Chlorophyll molecules are used in pharmacy as photosensitizer for cancer therapy. Their roles as
modifier of genotoxic effects are becoming increasingly important, besides these it being known to
have multiple medicinal uses. Chlorophyll has its place in modern medicine. Here, we present a
review of recent developments in medicinal uses of chlorophyll. This article enumerates therapeutic
claims of chlorophyll as drugs based on investigative findings of modern science. A brief overview of
research and developments of medicinal uses of chlorophyll will be presented in this review along
with challenges of potential applications of chlorophyll and its derivatives as chemotherapeutic agents
Keywords: Chlorophyll, medicine, genotoxity, photosensitizer
Abbreviations:
CHL: Chlorophyllin
ROS: Reactive oxygen species
PDT: Photodynamic therapy
PSMA: Prostrate-specific membrane antigen
ALA: Aminolevulinic acid
CDK: Cyclin dependent kinase
Can be cited as:
V.K. Mishra, R.K. Bacheti and Azamal Husen, 2011. Medicinal Uses of Chlorophyll: a critical overview. In: Chlorophyll: Structure,
Function and Medicinal Uses, Hua Le and and Elisa Salcedo, Eds., Nova Science Publishers, Inc., Hauppauge, NY 11788 (ISBN 978-1-
62100-015-0), pp.177-196. (https://www.novapublishers.com/catalog/product_info.php?products_id=22468)
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1. Introduction
Natural products have been the most important source of drugs. Throughout history, these products
have been used as important source of anticancer and chemopreventive agents. Many natural products
from our daily consumption of fruits, vegetables, tea beverages whose active ingredients have
potential health benefits. Recently, their uses are becoming increasingly popular as evident from the
sales of food supplements/functional foods which is growing at an amazing proportion, $4.59 billion
for 2006 and $4.79 billion for 2007 (Knasmüller et al., 2008). Despite, growing body of epidemolgical
and investigative findings supporting health claims of dietary supplements, there is urgent need to
ensure consumer concern about their efficacy and potentiality as medicine . Among several dietary
phytochemicals, chlorophyll being most ubiquitous natural pigments with physiological effects to cure
of chronic diseases, such as some forms of cancer.
The chlorophyll and its derivatives have long history in traditional medicine ((Esten and
Dannin, 1950; Kephart, 1955), and also various therapeutic uses including wound healing (Dashwood,
1997), anti-inflammatory agent (Bower, 1947; Larato et al., 1970), internal deodorant (Young et al.,
1980). Although these applications illustrate various medicinal uses of chlorophyll but interestingly
recent research works are more focused on its role as potent anti-mutagen and anti-carcinogen
(Dashwood, 1997, 2002, Egner et al., 2001, 2003), and also as photosensitizer in photodynamic
therapy (Henderson et al., 1997; Park, 1989; Li, et al., 2005). The intent of present article is aimed at
providing better understanding of science based health claims of chlorophyll.
2. Chemotherapeutic Potential of Chlorophyll
2.1. Chlorophyll and Its derivatives
Chlorophyll has a porphyrin ring similar to that of heme in hemoglobin, although the central atom in
chlorophyll is magnesium instead of iron (Figure 1). Chlorophyllin is a semi-synthetic mixture of
sodium copper salts derived from chlorophyll. During the synthesis of chlorophyllin, the magnesium
atom at the center of the ring is replaced with copper and the phytol tail is lost. Unlike natural
chlorophyll, chlorophyllin is water-soluble. Although the content of different chlorophyllin mixtures
may vary, two compounds commonly found in commercial chlorophyllin mixtures are trisodium
copper chlorin e6 and disodium copper chlorin e4 (Figure 2).
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(a)
(b)
Figure 1. Molecular structure of (a) chlorophyll and (b) red blood cell
An excellent account of structure of chlorophyll and its derivatives, stability, bioavalability and their
cancer preventing activity has been reviewed by Ferruzzi and Blakesle (2007). Chlorophyllin as been
extensively studied for its effect in animal/human, and also utilized as food grade colorant in Europe,
Asia and to a more limited and growing extent in United States (Ferruzzi and Blakesle, 2007). Some of
the important chlorophyll and its derivatives are listed in Table 1.
Table 1. Chlorophyll and its derivatives used in medicine
Natural chlorophyll
Chlorophyll a, b, c, d, e
Metal free chlorophyll derivatives
Pheophytin, Pyropheophytin
Metallochlorophyll derivatives
Zn-Pheophytin
Zn-pyropheophytin
Chlorophyllide
Pheophorbide
Cu(II)chlorin e 4
Cu-chlorin e 6
Cu-chlorin e 4 ethyl ester
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Figure 2. Structure of chlorophyll and its derivatives
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2.2. Potential Mechanism of action of Chlorophyll
Chlorophyll derivatives after release from the plant food matrix, natural chlorophyll (CHL) derivatives
are exposed to the acidity of the gastric digestion resulting in conversion to respective metal-free
pheophytins (PHE). Following digestive degration of commercial chlorophyll derivatives, they are
absorbed by intestinal cells and finally passes into blood circulation (Egner, 2000, Ferruzzi et al.,
2002). Chlorophyll and its derivatives act through variety of mechanisms which include: (i)
antioxidant activity; (ii) modifier of genotoxic effect; (iii) inhibition of cytochrome P450 enzymes;
(iv) induction of phase II enzymes; (v) increased level of gluta-thione S-transferase; (v) cell
differentiation, cell arrest and apoptosis.
2.2.1. Antioxidant Effect
The major source of reactive oxygen species (ROS) is electron leakage from the mitochondrial
electron transport chain, which then reacts with molecular oxygen forming ROS. ROS includes free
radical such as superoxide (O2·−) and hydroxyl radical (OH·) and non-radical species such as hydrogen
peroxide (H2O2). These free radicals set chain reaction of free radical formation when they interact
with another molecule. High concentration of ROS causes oxidative damage to bio-molecules such as
lipids, proteins and nucleic acids, leakage of electrolytes via lipid peroxidation, which results in the
disruption of the cellular metabolism. Antioxidants act as an electron sink that neutralizes free radicals
either through preventing free radical formation (preventive antioxidants) or preventing free radical
chain propagation. Free radicals have been implicated to play an important role in development several
diseases (Yoshikawa et al., 2000; Devasagayam et al., 2004; Knasmüller et al. 2008 ), which include
some forms of cancer, neurological disorders, inflammatory diseases, dermatitis, tissue damage and
sepsis, cardiovascular ailments (Elahi and Matata, 2006; Lefer and Granger 2000), and rheumatoid
arthritis , idiopathic infertility (Agarwal et al., 2006; Pasqualotto et al., 2001), decreased immune
function, several diseases of ageing (Von et al., 2004). There are contradictory views about ROS and
cancer-one suggesting increased level of ROS causes cancer formation and proliferation while other
opined that ROS may kill cancer cells (Schumacker, 2006).
Dietary chlorophyll derivative has ability to scavange long lived free radicals, such as 1,1-
diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS)
(Ferruzi et al., 2002; Lanfer-Marquez et al., 2005). Natural chlorophyll a and b exhibited lower
antioxidant activity than metal-free derivative (chlorins, pheophytins, and pyropheophytins), however
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metallo-derivatives (Mg-chlorophylls, Zn-pheophytins, Zn-pyropheophytins, Cu-pheophytina, and Cu-
chlorophyllins) have highest antioxidant activity (Lanfer-Marquez et al., 2005). Chlorophyll and
derivatives have potent antioxidant and radioprotective effects in vitro and in vivo. They inhibit lipid
peroxidation (Sato et al., 1983, 1984, 1985), protein oxidation, DNA damage, membrane damage
(Kamat et al., 2000; Kumar et al., 2001). A burst of free radical formation is demonstrated during
cerebral ischaemia and reperfusion induced injury. Chlorophyll salt and the aqueous extract of
Baccopa monneria and Valeriana wallichii exerts neuroprotective effects (Rehni et al., 2007).
2.2.2. Modifier of genotoxic effect
Hartman and Shankel (1990) reviewed inhibitors that directly interact with mutagen and carcinogen
and sequester so that they may not have any harmful effect on body. These inhibitors act as interceptor
molecules against mutagen and carcinogen. Interceptors are are proficient in binding to, or reacting
with, mutagenic chemicals and free radicals, and serves as a first line of defense against mutagens and
carcinogens (Hartman and Shankel, 1990). Following interception, the defense mechanism may either
involve induction of detoxification enzyme or inhibition of carcinogen activating enzyme. Data on
activity profiles of antimutagens has been reviewed in vitro and in vivo data by Waters et al. (1996).
Among the various inhibitors reviewed, chlorophyllin (CHL) was identified as almost uniformly
protective against a broad range of direct- and indirect-acting mutagens, including aflatoxins,
polycyclic aromatic hydrocarbons, heterocyclic amines, alkylating agents and several miscellaneous
compounds (Arimoto et al., 1993; Breinholt et al., 1995; Tachino et al., 1994; Negishi et al., 1997;
Dashwood et al., 1992, 1996, 1998, Dashwood, 2000).
Although chlorophyll and its compounds has potential to act anti- mutagens in vitro (Negishi et
al., 1989, Dashwood et al., 1995) however they have shown chemopreventive properties in vivo such
as chemoprevention of aflatoxin B1 (AFB1) hepatocellular carcinoma (HCC) in rainbow trout model
(Breinholt et al., 1995, Dashwood et al., 1998; Reddy et al., 1999 Pratt et al., 2006; Simonich et al.,
2008; Castro et al., 2009) and in rodent model (Guo et al.,1995; Hasegawa et al.,1995, Simonich et
al., 2007) and human intervention (Yu, 1995; Egner et al., 2001). Chlorophyllin has strong binding
capacity to acridine, more effectively than resveratrol and xanthenes (Osowski et al., 2010), which
prevents DNA-mutagen intercalation.
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2.2.3. Inhibition of Cytochrome P450 Enzymes
Cytochrome P450 enzymes are involved in the removal of carcinogenic compounds from the body.
However, in some cases they can also activate compounds consumed in food, converting
procarcinogens to carcinogens. Aflatoxin B1 is not carcinogenic until converted to the electrophilic 8,9
–epoxide, which can form adduct with DNA. The metabolic activation of AFB1 is mediated by
cytochrome p450 (Tachino et al., 1994; Yun et al., 1995). Dietary supplementation of chlorophyllin
has significantly reduced AFB-1 induced DNA damage in the liver of rainbow trout and rats
(Breinholt et al., 1995). The major pathway in metabolism of aflatoxin B1 in human is presented in
Figure 3 (Guengerich et al., 2002, Guengerich, 2008).
CYP1B1 is also implicated in tobacco smoke-related cancers in several organs. Tobacco
smoke contains several procarcinogens, including polycyclic aromatic hydrocarbons (PAHs),
nitrosamines and arylamines. PAHs can be activated into carcinogens by CYP1A1, CYP1A2 and
CYP1B1. Benzo[a]pyrene (BP) is a potent pro-carcinogen and ubiquitous environmental pollutant.
John et al. (2010) observed the induction and modulation of CYP1A1 and CYP1B1 and 10-
(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPdG) adduct formation
in DNA from primary normal human mammary epithelial cell (NHMEC) strains. Maximum percent
reductions of CYP1A1 and CYP1B1 gene expression and BPdG adduct formation were observed
when cells were pre-dosed with chlorophyllin followed by administration of the carcinogen.
Chlorophyllin is likely to be a good chemoprotective agent for a large proportion of the human
population.
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Figure 3. Metabolism of aflatoxin B1 in human (Guengerich et al., 2002, Guengerich, 2008)
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2.2.4. Induction of phase II Enzymes
Induction of phase II response is recognized as an effective strategy for protecting cells against
oxidants, electrophiles.Phase II enzyme include glutathione-S-transferase, UDP glucoronosyl
transferase, sulfotransferase, and oxidoreductase. Phase II enzymes bind to oxygenated carcinogens
making highly polar molecule that are excreted. Phase II enzymes decrease carcinogenicity by
blocking carcinogen metabolic activation and enhancing carcinogen detoxification. Although the
Brassica vegetables have long been known to contain potent inducers of mammalian phase 2 enzymes
(Dinkova-Kostova et al., 2004), chlorophyllin may also increase the activity of the phase II enzyme,
quinone reductase (Dingley et al., 2003). Chlorophylls, chlorophyllin and related tetrapyrroles are
significant inducer of mammalian phase II cytoprotective genes, inducing the phase 2 enzyme
NAD(P) H:quinone oxidoreductase 1 (NQO1) in murine hepatoma cells (Fahey et al., 2005). The
drug metabolizing enzyme comprises phase I (oxidation, reduction and hydrolysis). Physiological
balance between Phase I and Phase II enzymes, and their level of expression and genetic
polymorphism might dictate the sensitivity or risk of individual exposed to carcinogenic species
(Kensler, 1997).
2.2.5. Effect of Chlorophyll on Cell Differentiation, Cell arrest and Apoptosis of
Cancer Cells
Generally, growth rate of pre-neoplastic or neoplastic cells is fast than normal cell. Therefore,
induction of apoptosis or cell cycle arrest can be an excellent approach to inhibit the promotion and
progression of carcinogenesis. Distinct from apoptotic events in the normal physiological process,
which are mainly mediated by interaction between death receptors and their relevant ligands (Jacks
and Weinberg, 2002), many dietery supplements appear to induce apoptosis through the mitochondria-
mediated pathways. The cytotoxic effects of chemotherapeutic compounds on neoplastic cells can be
monitored by measuring their effect on mitochondria, caspases and other apoptosis –related proteins.
Chlorophyllin induced apoptosis in HCT116 human colon cancer cells, via a cytochrome c–
independent pathway (Diaz et al., 2003).
Progression through cell cycle is a sequential process that directs cells to pass through G1, S.
G2 and M. There are G1-S/ or G2-M checkpoints that halts cell division whenever necessary. Cyclin
dependent kinase (CDKs) CDK inhibitors governs the progression of the cell cycle. Cell cycle arrest
induced by chemopreventive compounds potentially affects and blocks the continuous proliferation of
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tumorogenic cells. Lower doses of CHL also were observed to induce cell-cycle arrest and strongly
altered markers of cell differentiation, such as E-cadherin (Carter et al., 2004).A recent study showed
that human colon cancer cells undergo cell cycle arrest after treatment with chlorophyllin (Chimploy,
2009). The mechanism involved inhibition of ribonucleotide reductase activity. Ribonucleotide
reductase plays a pivotal role in DNA synthesis and repair, and is a target of currently used cancer
therapeutic agents, such as hydroxyurea (Chimploy et al., 2009).
3. Applications in Cancer Chemotherapy
Cancer development is a long term process that involves initiation, promotion and progression that
ultimately leads to spread from one area of the body to another during the late metastasis stage.
Current clinical therapies which include surgery, radiotherapy and chemotherapy are limited to
particularly during metastasis phase. However, there is increasing body of evidences from
epidemiological and pathological studies that certain dietary substances may prevent or slow down
progression of cancer. Because advance metastasis stage cancer are almost impossible to cure,
therefore, cancer chemoprevention and containment at early stage is highly desirable. Dietary
chemopreventive agents seems to have variety of cellular and molecular mechanism that may inhibit
carcinogenesis (blocking agent) or suppress promotion and progression of carcinogenesis (suppressive
agent) or function as both. Many dietery substances such as retinoic acid, sulforaphane, curcumin,
EGCG, apigenin, qurecetin, chrysin, silibinin, silymarin and resveratrol acts through induction of
apoptosis. Potential mechanism underlying effectiveness of some of the dietery constituents is
presented in Table 2. Many dietary compounds including chlorophyll possess cancer protective
properties that include cellular detoxifying mechanism and antioxidant property that protects against
cellular damage caused by environmental carcinogens or endogenously generated reactive oxygen
species. These dietary substances can affect death signaling pathways which could prevent
proliferation of tumor cells.
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Table 2: Potential Mechanism of action of some of the dietery chemopreventive compounds (modified
from Chen and Kong, 2005)
Class
Function
Compounds
Source
Cancer Blocking agent
Enhanced
detoxification
of chemicals
Indole-3-Carbinol
Cruciferous vegetables
Chlorophyll and its
derivatives
Green leafy vegetables
Sulpforaphane
Cruciferous vegetables
Curcumin
Turmeric
Inhibit cytochrome
P450
Isothiocyanates
Cruciferous vegetables
Selenium
Nuts and meat
Vitamin E
Vegetable oil
Trap carcinogen
Flavonoids
Fruits and Vegetables
Chlorophyllin
Commercial preparation from
chlorophyll
Suppressive agents
Cell cycle disruption
/or induce apoptosis
Chlorophyllin
Commercial preparation from
chlorophyll
EGCG
Green tea
Quercetin
Onion and tomatoes
Resveratrol
Grapes
Curcumin
Turmeric
Sulphoraphane
Cruciferous vegetables
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Chlorophyll has a potential to act as chemopreventive agent. Clinical trials with chlorophyllin have
reduced aflatoxin-DNA adducts in individuals at high risk for liver cancer (Kensler et al, 1998, Dingley
et al., 2003). In another clinical trial on patient with fibroadenomastosis of breast cancer, the drug
mamoclam- containing mega-3 polyunsaturated fatty acids, iodine and chlorophyll derivatives, produced
from the brown sea alga laminaria, was effective in pain relief and breast cyst regression (Bezpalov et
al., 2005 ).
Chlorophyll can assist with the effects of dietary and environmental exposure to carcinogens.
Notable examples are the tobacco-related carcinogens (e.g., nitrosamines and polycyclic aromatic
hydrocarbons-PAH), heterocyclic amines produced from sustained, high-temperature cooking of meats
and the fungal food contaminants aflatoxins. Research indicates that chlorophyll reduces carcinogen
binding to DNA in the target organ by inhibition of carcinogen activation enzyme or degradation of
ultimate carcinogens with the target cells. In vitro and in vivo studies further substantiated medicinal
cures offered by chlorophyll derivatives. Elucidation of the molecular mechanisms of chemical
carcinogenesis provides insight into targets for chemoprevention. Microarray and proteonomics
analysis have shown alteration at the level gene expression and protein. Recently research
investigations showing involvement of transcriptional factors and their intervention by chlorophyll and
its derivative seems to be an attractive approach showing precise action at benefits of chlorophyll at
cellular and molecular levels.
4. Photosensitizer
Photodynamic therapy (PDT) is increasingly becoming accepted as a treatment option for a variety of
cancer which is usually based on the photosensitisation of tumour cells with subsequent light exposure
leading to death of the malignant cells. The most commonly used photosensitisers, such as the
haematoporphyrin derivatives have a number of drawbacks - poor selectivity in terms of tumour drug
accumulation and low extinction coefficients so that relatively large amounts of drug and/or light are
needed in order to obtain a satisfactory phototherapeutic response. These have led to the development
of a further generation of photosensitisers based on chlorophyll derivatives, which are characterized by
increased phototoxicity and strong absorption which allows deeper light penetration into tissues, rapid
tissue clearance and minimal extravasation from the circulation (Rosenbach-Belkin et.al., 1996).
Aminolevulinic acid (ALA), a building block of tetrapyrroles, synthesized during chlorophyll
biosynthesis, has shown photodynamic destruction of cancer cells (Reibeiz et al., 2002). It is available
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as porphyric insecticides and show photodynamic property. It can be easily taken up by transformed
cells, and is rapidly cleared from the circulatory stream within 48 hr of treatment (Reibeiz et al., 2002).
Conjugating Cp 6 with histamine can help improve the effectiveness of PDT in oral cancer cells by
enhancing its intracellular delivery (Parihar et al., 2010). "Radachlorin"(®), also known in the
Bremachlorin, a composition of 3 chlorophyll a derivatives in an aqueous solution, was introduced
into the Russian Pharmacopoeia. Iand may be commercialized as a prospective second-generation
photosensitizer (Kochneva et al., 2010). Prostate-specific membrane antigen (PSMA), a validated
biomarker for prostate cancer, has attracted considerable attention as a target for imaging and
therapeutic applications for prostate cancer. PSMA inhibitor, i.e. conjugate of pyropheophorbide has
been used for targeted PDT application and the mechanism of its mediated-cell death in prostate
cancer: inducing apoptosis via activation of the caspase-8/-3 cascade pathway (Liu et al., 2010).
5. Contraindications and Safety
Natural chlorophylls are not known to be toxic, and no toxic effects have been attributed to
chlorophyllin despite more than 50 years of clinical use in humans. Although few contraindications
have been reported by some investigators ((Chernomorsky, 1988; Gogel et al., 1989; Kephart , 1995;
Egner et al., 2003 , Hendler et al., 2008) ) but much serious ill effects are less known. There is lack of
reports about the safety of chlorophyll or chlorophyllin supplements in pregnant or lactating women.
Although there is no major contraindication reported so far as but in order to be used in modern,
pharmacological aspects the way these medicine interacts with human system needs to be further
explored so as to recommend its safe, effective and widespread use of in medicine.
6. Challenges of potential application chlorophyll and its derivatives as
chemotherapeutic agents
Dietary chemoprevetive compounds offer great potential in fight against cancer. The mechanistic
insight into chemoprevention of carcinogenesis includes regulation of cell defensive and cell-death
machineries. Though progress have been made in understating apoptosis, and cell cycle arrest in
relation to chlorophyll and its derivatives, signaling pathways and gene expression events leading to
pharmacological effects require further investigation. The ultimate goal is translation of the results of
in vitro signaling and gene expression obtained in animal cell culture system /animal model to
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beneficial pharmacological effects which have several challenges that need to be overcome. One of the
concern is induction of detoxifying enzymes by chemotherapeutic agents varies within human
population. Since the cancer development is a long term process, there is need to explore suitable
potency indicators to assess the effect of chemopreventive agents. Dietery chemopreventive agents
may not possess pharmacologically active properties to be used as drug. Studies on pharmacokinetics
and toxicity profile of chemopreventive agents are important in drug development. Synergistic effect
chemopreventive agent in association with other efficacious drug molecule might enhance the
efficacy. Ultimately to convert a dietery chemopreventive agents into a viable drug, a clear
understanding in this area will provide impetus for future developments.
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