http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2707034/
 Mar Drugs. 2009 June; 7(2): 71–84. 
Matrix Metalloproteinase Inhibitors (MMPIs) from Marine Natural Products: the Current Situation and Future Prospects
This article has been 
cited by other articles in PMC.
 
 
Abstract
Matrix
 metalloproteinases (MMPs) are a family of more than twenty five 
secreted and membrane-bound zinc-endopeptidases which can degrade 
extracellular matrix (ECM) components. They also play important roles in
 a variety of biological and pathological processes. 
Matrix 
metalloproteinase inhibitors (MMPIs) have been identified as potential 
therapeutic candidates for metastasis, arthritis, chronic inflammation 
and wrinkle formation. Up to present, more than 20,000 new compounds 
have been isolated from marine organisms, where considerable numbers of 
these naturally occurring derivatives are developed as potential 
candidates for pharmaceutical application. Even though the quantity of 
marine derived MMPIs is less when compare with the MMPIs derived from 
terrestrial materials, huge potential for bioactivity of these marine 
derived MMPIs has lead to large number of researches.
Saccharoids, 
flavonoids and polyphones, fatty acids are the most important groups of 
MMPIs derived from marine natural products. In this review we focus on 
the progress of MMPIs from marine natural products.
 
Keywords:
 Matrix
 metalloproteinases (MMPs), 
Matrix metalloproteinase inhibitors (MMPIs), 
 Tissue inhibitors of metalloproteinase (TIMPs), 
Marine natural 
products, 
NF-κB, 
AP-1
 
1. Introduction
Matrix
 metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases
 that degrade extracellular matrix (ECM) components and play important 
roles in a variety of biological and pathological processes [
1].
 MMPs regulate the synthesis and secretion of cytokines, growth factors,
 hormone receptors, and cell adhesion molecules. They also contribute to
 the growth and development, morphogenesis, tissue remodeling, 
angiogenesis, arthritis, cardiovascular disease, stroke, multiple 
sclerosis, neurodegenerative diseases, allergies, as well as cancer and a
 series of physiological and pathological processes [
2, 
3].
 In tumor progression MMPs are important not only in invasion, 
angiogenesis, and metastasis, but also MMPs have roles in cancer cells 
transformation, growth, apoptosis, signal transduction and immune 
regulation [
4, 
5].
 Therefore, the development of matrix metalloproteinase inhibitors 
(MMPIs) to treat some important diseases, including cancers, 
neurodegenerative diseases, cardiovascular diseases and various kinds of
 inflammatory diseases have broad prospects [
3–
9].
 
Generally
 
MMPs consist of a propeptide domain having about 80 amino acids, a 
catalytic metalloproteinase domain of about 170 amino acids, a linker 
peptide of variable lengths (also called the “hinge region”) and a 
hemopexin domain of about 200 amino acids [
10].
 However, not all of these domains are essential for MMPs; some MMPs 
lack the linker peptide and the hemopexin domain.
 MMPs contain a Zn2+
 catalytic core; this zinc-binding site has a conservative HEXXHXXGXXH 
amino acid sequence. The catalytic domains of MMPs show homology, as 
their three-dimensional (3D) structure of the enzyme active site are 
highly conservative. The catalytic domain includes a pocket called 
the“S1′ pocket” located to the right of the zinc atom. This pocket is 
hydrophobic in nature, but variable in depth depending on the MMP. It is
 therefore one of the determining factors of substrate specificity of 
MMPs. Accordingly, the S1′ pocket in the catalytic domains of MMPs is 
most notable, and its depth, as well as the length and amino acid 
sequence of the peptide which around the S1′ pocket is 
important basis 
for design and synthesis of the MMPIs [11–13].
MMPs’ activities can be regulated by endogenous inhibitors, such as tissue inhibitors of metalloproteinase (TIMPs), α
2-macroglobin, heparin and the reversion-inducing cysteine-rich protein with kazal motifs (RECK) [
4, 
5].
 There are four TIMPs in humans (TIMP-1, -2, -3 and -4) with 22–29 kDa. 
TIMP-1 and TIMP-3 are glycoproteins, but TIMP-2 and TIMP-4 do not 
contain carbohydrates. They inhibit all MMPs tested so far [
14].
 These four TIMPs have different expression and distribution in the 
tissue and may be responsible for regulating the activity of a large 
number of protease families 
in vivo, including the
 
metalloproteinases of a disintegrin and
 metalloproteinases (ADAMs) 
family. However, the TIMPs and other endogenous inhibitors have 
diversity of biological functions and also the protein delivery 
techniques are not developed, the use of these endogenous inhibitors in 
clinical applications have been delayed [
4, 
5].
 
Design and synthesis of MMPIs has gone through several stages of development over the past 20 years [
13].
 Originally MMPIs was designed by simulating MMPs substrate, this is 
the
 first-generation of MMPIs. Most of them are peptides and their 
derivatives. Inhibition is occurred by chelating the Zn
2+ of the MMP by the group present in inhibitors, such as hydroxylamine, carboxyl, SH, etc.. Mainly the Zn
2+
 is chelated with the oxyammonia-base by combining the substrate analogs
 peptide, at the same time through the substrate analogs peptide combine
 with the catalytic domains of MMP, and thus plays the inhibitory 
effect.
Strong Zn
2+ chelating agents such as hydroxamate as a
 class of MMPIs have been developed, representative of these inhibitors 
are the British Biotech’s Batimastat (BB-94) and Marimastat (BB-2516), 
and they all have ideal inhibitory activity with the MMPs. Even through,
 these compounds can interact with Zn
2+; they can’t 
distinguish between different MMPs
. 
Therefore, the uses of 
first-generation of MMPIs as drugs in clinical applications were 
restricted.
Their shortcomings include: poor selectivity of MMPs, 
hydroxylamine substances have low oral bioavailability, the metabolism 
is not stable, poor solubility and the drug toxicity increase after 
amelioration. Therefore it was strongly suggested that the first 
generation of MMPIs must use another group in place of hydroxylamine 
group as a Zn
2+ chelating group, or design new non-peptide 
MMPIs.
 For these proposed MMPIs, first, 
lead (Pb)  compounds were selected 
through high-throughput screening, then these lead compounds are 
reformed with the Safety Analysis Report (SAR) guidance, finally these
 
new reagents with better effect was formed.
 The second-generation MMPIs 
also contain Zn
2+ chelating group. These drugs have 
eliminated some of shortcomings of peptide drugs with considerable 
selectivity towards MMPs. However, in clinical applications they also 
have been impeded due to effectiveness and side effects [
15, 
16].
 
Clinical
 trials for the anti-cancer and anti-arthritis effects have been carried
 out using many early MMPIs. However, only a few MMPIs were effective 
(such as Marimastat, the overall survival rate of the gastric cancer and
 pancreatic cancer patients increase). Therefore they have not been used
 in the later stages of clinical trials.
At present,
 only one MMPI 
(Periostat) is being used clinically 
for periodontitis therapy [
5, 
15].
With
 intensive studies on MMPs, the MMPs host-cell defense functions and 
physiological functions have been discovered by researchers. The early 
MMPIs whether peptide inhibitors or small molecule inhibitors, their 
activities are most dependent on the Zn
2+ chelating group and MMPs S1′ pocket combined group. However the Zn
2+
 chelating group also reduces these early MMPIs’ selectivity. In 
addition, these early MMPIs inhibit some MMPs physiological functions 
and some other metalloprotease such as DPP III and leucine 
aminopeptidase, when they inhibit the abnormal MMPs in pathology 
situation [
5, 
17].
To
 sum up the above arguments, the clinical trials of MMPIs in 
broad-spectrum, face the obstacle, as well as the normal physiological 
functions of MMPs should be further studied for the choice of drugs 
which are selectively acting on them for the MMPs relevant diseases. 
MMPs S1′ pocket determine the specificity of substrates and inhibitors 
in a large extent, therefore
 the S1′ pocket is very important for the 
design and synthesis of MMPIs. Design of MMPIs should be based on the 
unique functions of MMPs S1′ pocket, not only 
to increase the 
selectivity for this MMP, but also greatly reduce the inhibition of 
other class of metalloprotease such as ADAMs.
 At present, development of
 the new generation of MMPIs is guided by this idea. In addition, 
development of
 new type of MMPIs with different inhibiting mechanisms 
can increase the drugs’ selectivity; which may play a key role in the 
treatment of various diseases related to MMPs [
18–
21].
Broadly
 speaking, the mechanisms of inhibiting the activity of MMPs include, 
direct inhibition of the enzymes, blocking the MMPs proenzyme 
activation, suppressing the synthesis of MMPs in the gene level, and so 
on.
The MMPIs can be divided into four classes:
-  the natural MMPIs 
secreted by tissues;
-  synthetic MMPIs;
-  MMPIs screened from natural 
products
-  and the MMPIs screened from the phage display random peptide 
library and antibody library.  
The synthetic MMPIs and natural product 
derived MMPIs are the hot spots. In recent years, due to the synthetic 
small molecule inhibitors meet a variety of issues in clinical 
applications, more attention is given to the research of MMPIs derived 
from natural products.
Lots of 
successful research work have been conducted 
to identify MMPIs from land
 natural products, also got a lot of results. For instance, Kim 
et al.
 were screened for nearly 90 kinds of extracts from clinical application
 herbal medicines, and found that the extracts from 
Baicalin, Cinnamon, 
Euonymus, and Magnolia have strong inhibitory effects on MMPs [
22–
24].
 However we should not forget that the ocean is treasure house which is 
full of natural products with amazing biological and pharmacological 
activities. About 80% of the planet’s animal and plant growth in the 
ocean, and the variety of marine bacteria can reach 500–100 million. 
Therefore discovering the ideal MMPIs from marine natural products is a 
very hot topic at present.
The leitmotiv along this review is to sum up 
the progress of research work carried out on identifying MMPIs from 
marine natural products. We divided the marine derived MMPIs into three 
classes, marine saccharoid MMPIs, marine flavonoids and polyphenols 
MMPIs and marine fatty acid MMPIs, and their properties will be 
discussed in this review.
 
2. MMPIs from marine natural products
2.1. Marine saccharoid MMPIs
The
 marine saccharoid MMPIs are very popular among marine derived MMPIs 
area. The most of marine saccharoid MMPIs inhibit MMP by direct 
down-regulation of MMP-9 transcription or via inhibition of activator 
protein-1(AP-1) pathway or nuclear factor κB (NF-κB) pathway. Kim 
et al.
 report the inhibitory effect of chitooligosaccharides (COS) on 
activation and expression of matrix metalloproteinase-2 (MMP-2) in 
primary human dermal fibroblasts (HDFs) for the first time. COS with 3–5
 kDa exhibited the highest inhibitory effect on MMP-2 activity in HDFs, 
and protein expression of MMP-2 was also inhibited by COS with same 
molecular weight. This inhibition was caused by the decrease in gene 
expression and transcriptional activity of MMP-2[
25]. Quang 
et al.
 have investigated the effect of Chitooligosaccharides (COS) on activity
 and expression of MMP-9 in HT1080 cells by gelatin zymography, RT-PCR, 
gene reporter assay, and western blot analysis. They found that MMP-9 
inhibition in the presence of COS was clearly observed in gelatin 
zymography. Specifically, 1- to 3-kDa COS (COS-I) exhibited the highest 
inhibitory effect on MMP-9 activity in HT1080 cells among tested 
molecular mass fractions. It was also found that COS-I was capable of 
inhibiting both gene and protein expression of MMP-9 (P26
 
 
].
 The novel low molecular-weight carboxylated Chitooligosaccharides 
(CCOS) has been evaluated for MMP-9 inhibitory effect on human 
fibrosarcoma cell line [
27].
 A clear dose-dependent inhibition on MMP-9 mediated gelatinolytic 
activities were observed in HT1080 cells following the treatment with 
CCOS in zymography experiments. Transfection studies carried out with 
MMP-9 and AP-1 reporter constructs suggested that the observed reduction
 in MMP-9 expression was due to down-regulation of MMP-9 transcription 
which mediated via inhibition of AP-1. However, in the presence of CCOS,
 NF-κB and TIMP-1 expression levels remained constant [
27].
Adriana 
et al. investigated on the shrimp heparin-like glycosaminoglycan isolated from 
L. vannamei
 which was able to interfere on MMP-9 activity in activated human 
leukocytes. And it has the capacity to reduce 90% MMP-9 activity, either
 in a lower or higher concentrations (10 and 100 μg/mL), with pronounced
 effects [
28].
 In present studies, sulfated glucosamine (SG) has been reported to 
relieve joint pain and inflammation in many arthritis patients. Niranjan
 
et al. studied for SG inhibitory effects on MMP-2 and MMP-9 in
 human fibrosarcoma cells. Expression and activity of above MMPs studied
 suggested SG as a potent MMP inhibitor, and inhibition of MMP-2 and 
MMP-9 was due to down-regulation of transcription factor, NF-κB. 
However, expression of activator protein-1 (AP-1) was not affected by SG
 treatment. Moreover, down-regulation of NF-κB resulted in production of
 low levels of both NF-κB p50 and p65 proteins and directly affected 
activation process of MMP-2 and MMP-9 expressions [
29].
Angiogenesis
 is involved in initiating and promoting several diseases such as cancer
 and cardiovascular events. Chen et al. obtained highly sulfated 
λ-carrageenan oligosaccharides (λ-CO) by carrageenan depolymerization. 
They have demonstrated that λ-carrageenan oligosaccharides could 
effectively inhibit angiogenesis in the CAM (chick chorioallantoic 
membrane) model and human umbilical vein endothelial cells (HUVECs). 
Significant inhibition of vessel growth was observed at 200 μg/pellet. A
 histochemistry assay also revealed a decrease of capillary plexus and 
connective tissue in λ-CO treated samples. λ-CO inhibited the viability 
of cells at the high concentration of 1 mg/mL, whereas it affected the 
cell survival slightly (>95%) at a low concentration (30
].
Wang 
et al. isolated the sulfated S. maindroni ink polysaccharide (SIP-SII) from cuttlefish 
Sepiella maindroni,
 and examined the effects of SIP-SII on the expression of matrix 
metalloproteinases MMP-2 and MMP-9 as well as tumor cell invasion and 
migration. SIP-SII (0.8–500 mg/ml) significantly decreased the 
expression of MMP-2 activity in human ovarian carcinoma cells SKOV3. No 
significant decrease of MMP-9 was detected in the cell line after 
SIP-SII treatment [
31].
Fucoidan
 is a uniquely-structured sulfated polysaccharide found in the cell 
walls of several types of brown seaweed which has been recently 
evaluated for its bioactivities by Ye 
et al. [
32].
 Enzyme-digested fucoidan extracts prepared from seaweed, Mozuku of 
Cladosiphon novae-caledoniae kylin showed in vitro invasion and 
angiogenesis abilities of human tumor cells. The mechanism of 
significant inhibition of HT1080 cells invasion by fucoidan extracts, 
possibly via suppressing MMP-2 and MMP-9 activities. Further, they 
investigated the effects of the fucoidan extracts on angiogenesis of 
human uterine carcinoma HeLa cells, and found that fucoidan extracts 
suppressed expression and secretion of vascular endothelial growth 
factor (VEGF) [
32].
Marine
 saccharoid MMPIs exhibit high MMPs inhibitory activity either by direct
 inhibition of the enzyme or by inhibiting the expression of MMPs. And 
also these marine saccharoid MMPIs have shown low toxicity levels. 
However, due to high molecular weight of theses MMPIs the 
structure-activity relationship and also the mechanism of the activities
 are hard to be addressed by the researchers. If these shortcomings are 
overcome in the future, marine saccharoid MMPIs have a great potential 
to be used in clinical applications.
2.2. Marine flavonoids and polyphenols MMPIs
Flavonoid glycosides, isorhamnetin 3-O-b-D-glucosides, and quercetin 3-O-b-D-glucoside were isolated from 
Salicornia herbacea and their inhibitory effects on matrix metalloproteinase-9 and -2 were evaluated in human fibrosarcoma cell line [
31].
 These flavonoid glycosides led to the reduction of the expression 
levels and activities of MMP-9 and -2 without any significant difference
 between these flavonoid glycosides in zymography experiments. Protein 
expression levels of both MMP-9 and MMP-2 were inhibited and TIMP-1 
protein level was enhanced by these flavonoid glycosides [
33].
Kim et al., for the first time, report a detailed study on the inhibitory effects of phlorotannins in brown algae, Ecklonia cava
 (EC) on MMP activities. A novel gelatin digestion assay could visualize
 complete inhibition of bacterial collagenase-1 activity at 20 μg/ml of 
EC extract during preliminary screening studies. Sensitive fluorometric 
assay revealed that EC extract can specifically inhibit both MMP-2 and 
MMP-9 activities significantly (P34
 
].
The active compound from methanol extracts prepared from roots of 
Rhodiola sacra has been identified as 3-(3, 4-dihydroxy-phenyl)-acrylic acid phenethyl ester (caffeic acid phenethyl ester, CAPE) [
35, 
36]. And Lee 
et al. found that these active compounds can down-regulate enhanced MMP -9 activities [
37].
Joe 
et al.
 examined the inhibitory effects of 29 seaweed extracts on 
transcriptional activities of MMP-1 expression. And found that the eckol
 and dieckol from 
Ecklonia species have showed strong 
inhibition of both NF-κB and AP-1 reporter activity, which were well 
correlated with their abilities to inhibit MMP-1 expression. In 
addition, MMP-1 expression was dramatically attenuated by treatment with
 the eckol or dieckol [
38].
Matrix
 metalloproteinases (MMPs), a key component in photoaging of the skin 
due to exposure to ultraviolet A, appear to be increased by 
UV-irradiation-associated generation of reactive oxygen species (ROS). 
Ryu et al. demonstrates that the alga 
Corallina pilulifera 
methanol extract which has been shown a high phenolic content, reduced 
the expression of UV-induced MMP-2 and -9 in human dermal fibroblast by 
dose dependently manner, and has also antioxidant activity capable of 
strongly inhibiting free radicals [
39].
In murine asthma model, Kim et al. observed that MMP-9 expression was significant reduced via the administration of 
Ecklonia cava extracts. And 
Ecklonia cava
 extracts reveal Suppressor of cytokine signaling-3 (SOCS-3) expression 
and a reduction in the increased eosinophil peroxidase (EPO) activities.
 Their results indicate that 
Ecklonia cava extracts may prove to be a useful therapeutic agent for the treatment of ovalbumin -induced asthma [
40].
The
 compounds eckol, 2dieckol, 6,6′-bieckol and 1-(3′,5′-dihydroxyphenoxy) 
-7-(2″,4″,6″-trihydroxy-phenoxy)-2,4,9-trihydroxydibenzo-1,4,-dioxin 
were extracted from brown algae, 
Ecklonia cava, and Ryu et al. 
have investigated these compounds inhibited the proinflammatory 
cytokines induced expression of MMP-1, -3 and -13 [
41].
Flavonoids
 and polyphenols MMPIs have excellent MMPs inhibitory activities; 
however they show a high toxicity level. Therefore, the pharmaceutical 
applications of these MMPIs are limited. Researchers should pay 
attention to reduce their toxicity levels by altering the structure in a
 way by preserves it’s bioactivity. Then this class of MMPIs will gain a
 huge potential to be used in clinical applications
2.3. Marine fatty acid MMPIs
Researchers
 have identified that 
the long-chain fatty acids could inhibit MMPs. 
however for different MMPs the degree of inhibition is different, such 
as oleic acid, elaidic acid can inhibit MMP-2 and MMP-9 with the 
micromol Ki values, although their inhibitory effects on collagenase-1 
(MMP-1) are weak, as assessed using synthetic or natural substrates [
42].
 The fatty acid chain length and its degree of saturation is related to 
the level of inhibition, as
 the fatty acids with long carbon chains 
showed stronger inhibition than the short ones, and the
 nonsaturation 
degree showed a positive correlation to the overall inhibitory capacity 
of the fatty acid chains [42,
43].
 Fatty acids also bind to neutrophil elastase, the parinaric acids, 
fluorescent-conjugated tetraenoic fatty acids of plant origin, are 
inhibitors of neutrophil elastase. cis-Parinaric acid (cis-PA) interacts
 with the enzyme in two inhibitory modes. The high affinity interaction 
(Ki = 55 +/− 6 nM) results in partial noncompetitive inhibition of 
amidolytic activity, with 82% residual activity. A lower affinity 
interaction with cis-PA (Ki = 4 +/− 1 microM) results in competitive 
inhibition [
44, 
45].
 the fatty acids also bind to 
plasmin, such as
The ability of oleic acid
 to modulate fibrinolysis was measured by following the 
urokinase-mediated and plasminogen-dependent cleavage of 125I-labelled 
fibrin clots. Oleic acid levels within the physiological range exerted
 a
 concentration-dependent inhibition of urokinase-mediated fibrinolytic 
activity [
46, 
47], and some other serine proteinases, meanwhile modulate their catalytic activities.
It
 is well known that the marine fishes are rich in omega-3 long-chain 
polyunsaturated fatty acids (ω3 LC-PUFAs), especially eicosapentaenoic 
acid (EPA) and docosahexaenoic acid (DHA), which are active nutrients [
48]. Suzuki 
et al.
 found that the inhibition of lung metastasis of a colon cancer cell 
line by EPA and DHA was associated with a reduced activity of MMP-9, 
however MMP-2 activity was not affected by the diet containing PUFAs [
49, 
50].
 The MMP-9 activity was reduced by in uterus, placenta and liver tissues
 of rat fed diets enriched with DHA, with a decreased activity of MMP-2 [
50].
 They explained their finding by a competition of the ω3 LC-PUFAs with 
arachidonic acid for incorporation into membrane phospholipids. This 
would consequently change the production of prostaglandin PGE2 and 
thereby affect on MMP activities.
Acetylenic fatty acids isolated from marine sponges have exhibited wide range of biological activities such as cytotoxicity [
51], antimicrobial [
52] and antifouling [
53] activities, and enzyme inhibition [
54]. Callysponginol sulfate A is the first sulfated C
24 acetylenic fatty acid from marine organisms. Fujita 
et al.
 2002 extracted the sodium 1-(12-hydroxy)octadecanyl sulfate from an 
ascidian collected in western Japan, inhibited MMP-2 in 2002. And both 
natural and synthetic forms inhibited MMP-2 with an IC
50 value at 9.0 μg/mL; thus the stereochemistry of the hydroxyl group did not influence the activity [
55]. And after one year, they reported another compound, callysponginol sulfate A, a new sulfated C
24 acetylenic fatty acid, extracted from the
 marine sponge, Callyspongia truncate [
56]. This compound inhibited recombinant MT1-MMP with an IC
50
 value at 15.0 μg/mL, however the desulfated callysponginol sulfate A 
did not show any inhibitory activity against MT1-MMP. Considering this 
result as well as the similar activity of structurally unrelated 
sulfated compounds, the MT1-MMP inhibition activity is probably a 
consequence of the sulfate [
56].
 
 
2.4. Other marine natural products MMPIs
Shark cartilage extracts researches are very popular in recently [
57].
 The compounds extracted from shark cartilage (such as NeovastatÒ, 
AE-941, U-995 etc.) have been investigated on their potential use as 
MMPIs. These compounds were analyzed with regard to their 
anti-angiogenic and antimetastatic effects on the activity of several 
MMPs [
58],
 because MMPs are intimately connected with angiogenetic and metastatic 
processes. The results revealed that NeovastatÒ inhibits enzymatic 
activity of MMP-2 with minor inhibition of MMP-1, -7, -9 and -13. And 
also interestingly the western blot analysis evidenced the presence of 
TIMP-like proteins within AE-941, could be responsible for its specific 
MMP inhibitory property [
59].
 The tissue inhibitors of metalloprotease 1, 2 and 3 (TIMP-1, -2, -3) 
and tumor suppressor protein genes have been cloned and characterized 
from shark cartilage extracts [
52, 
60, 
61].
Alkaloid Ageladine A extract from the marine sponge, 
Agelas nakamurai, and Ageladine A inhibited not only MMP-2, but also MMPs-1, -8, -9, -12, and -13 with IC
50
 values of 2.0, 1.2, 0.39, 0.79, 0.33, and 0.47 μg/mL, respectively, 
while its N-methylated derivatives did not inhibit MMP-2. As we know 
that many potent MMP inhibitors are known to bind with Zn
2+ in the catalytic domain. But Ageladine A was not capable to chelate Zn
2+.
 Moreover, the kinetic analysis indicated that inhibition of MMP-2 by 
Ageladine A was not competitive when judged in the Lineweaver-Burk plot.
 Thus, the inhibition mechanism of Ageladine A was presumed to be unique
 [
62].
The
 Atlantic cod (Gadus morhua) muscle contains a 21-kDa proteinase 
inhibitor. The inhibitor had properties similar to human TIMP-2. The 
inhibitor was found to inhibit the gelatin-degrading enzymes present in 
the gelatin-bound fraction. In addition, it inhibited gelatinolytic 
activity obtained from a human macrophage cell medium rich in MMP-9 [
63].
(+)-Aeroplysinin-1,
 an antibacterial brominated compound produced by certain sponges, was 
selected during a blind high-throughput screening as new potential 
antiangiogenic compounds obtained from marine organisms. The 
concentration of MMP-2 in the medium conditioned by aeroplysinin-treated
 cells was clearly lower than that in untreated cell medium. The MMP-2 
bands in aeroplysinin-treated cell conditioned media were 60 + 4% 
compared to those of untreated cells, whereas extracts of treated cells 
yielded MMP-2 bands that were almost twofold (1.77 + 0.04) those of 
untreated cells. Thus, aeroplysinin-1 seems to affect mainly the release
 of MMP-2 to the medium [
64].
 
3. Conclusions
The
 marine environment is characterized by high biodiversity offering vast 
variety of natural products which could be used as potential drugs, 
particularly in the area of cancer chemotherapy, such like the matrix 
metalloproteinase inhibitors. Therefore continuation of finding new 
leads in this area of extracting bioactivity compounds from marine 
natural products will make much sense.
MMPIs design and
 synthesis has been done for ages and has gone through several 
development stages. Although many of the synthetic inhibitors of MMPs 
showed good inhibitory activity, however, the compounds do not have an 
ideal MMPs selectivity, combined with others limitations such as the low
 oral bioavailability, unstable metabolism, biological toxicity, and 
also these inhibitors in clinical trials show excessive side effects. 
Due to these major shortcomings this type of MMPIs failed to be used as 
drugs [
3, 
5, 
65].
With MMPIs finding of functionality of MMP’s in normal physiology functions, the development of MMPIs entered a new period [
66, 
67].
 In recent years, the non-metal chelating agent class of MMPIs reports 
has begun to appear. Isolating MMPs from marine natural products has 
been gradually gained more attention. Some marine natural products have 
been isolated with MMPs inhibitory activities and further, some 
compounds have special restraint or high selectivity [
68].
 Such as Ageladine A which inhibit MMP-2 was not competitive judging 
from the Lineweaver-Burk plot. Thus, the inhibition mechanism of 
Ageladine A was presumed to be unique [
62]. These MMPIs will be the focus of future work.
 
Acknowledgements
This
 research was supported by a grant (M2007-0) from Marine Bioprocess 
Research Center of the Marine Bio 21 Center funded by the Ministry of 
Land, Transport and Maritime, Republic of Korea.
 
 
Abbreviations
- MMPs
- matrix metalloproteinases
- ECM
- extracellular matrix
- MMPIs
- matrix metalloproteinase inhibitors
- TIMPs
- tissue inhibitors of metalloproteinase
- RECK
- reversion-inducing cysteine-rich protein with kazal motifs
- ADAMs
- a disintegrin and metalloproteinases
- SAR
- safety analysis report
- COS
- chitooligosaccharides
- HDFs
- human dermal fibroblasts
- CCOS
- carboxylated chitooligosaccharides
- SGlc
- sulfated glucosamine
- NF-κB
- nuclear factor κB
- AP-1
- activator protein-1
- λ-CO
- λ-carrageenan oligosaccharides
- HUVECs
- human umbilical vein endothelial cells
- SIP-SII
- sulfated S. maindroni ink polysaccharide
- EC
- Ecklonia cava