Biology Reference
In-Depth Information
Drugs, Carotenoids and Other Compounds from Marine
Microalgae
The unique metabolic capabilities of microalgae offer the potential for
novel and promising natural products, which can fi ght various diseases
providing support to human life. These compounds include antioxidants,
antimicrobials, antitumor drugs, bio-adhesives, antifouling compounds,
and immuno-active agents, enzymes, polysaccharides, enzyme inhibitors,
herbicides, antimalarials, antimyotics, multi-drug resistance reverses
etc. (Kurano and Miyachi, 2004; Plaza et al., 2009).
Dunaliella
spp., for
example, contain compounds that exhibit various biological activities
such as antihypertensive, bronchodilator, analgesic and muscle relaxant
activities (Dufosse et al., 2005; FAO, 2004). The potential of cyanobacteria
as untapped sources of nutraceuticals have only recently been recognized.
Possibilities of their genetic modifi cation and mass cultivation under
controlled conditions offer scope to enhance yield of their bioactive
compounds in substantial amounts. Some of the novel compounds
isolated from cyanobacteria include plant growth regulators such as
gibberellic acid that promote re-differentiation, germination and platelet
formation, tyrosinase inhibitors, UV-absorbing compounds, sulfated
polysaccharides showing anti-HIV activity and novel antibiotics with
light-regulated activity (Otero and Vincenzini, 2003; Herrero et al., 2006).
Chlorella
(
C. vulgaris
) and
Spirulina
(S.
platensis
)
contain peptides that inhibit
angiotensin I-converting enzyme, and thereby helps control of coronary
heart disease. Oral administration of fractions of peptic digests into
spontaneously hypertensive rats at 200 mg/kg of body weight resulted
in marked antihypertensive effects (Suetsuna and Chen, 2001). Interest in
this fi eld has resulted in collection of cyanobacterial species for production
of their secondary metabolites such as dolastatins, originally isolated from
the Indian Ocean seashore. Cyanobacterial metabolites have proven to be
invaluable as tools in the dissection of signal transduction pathways in
mammalian cells and some are currently under clinical evaluation as drug
candidates. A plasmid from the marine cyanobacterium,
Synechococcus
spp., whose copy number is dependent on salinity, is being used to
develop a stable and controllable gene expression system (Otero and
Vincenzini, 2003; Burja and Radianingtylas, 2005). The red microalga of
genus
Porphyridium
is a source of biochemicals possessing nutritional and
therapeutic value. These compounds include polysaccharides (having anti-
infl ammatory and antiviral properties), long-chain polyunsaturated fatty
acids, carotenoids such as zeaxanthin and fl uorescent phycolipoproteins.
The red phycoliporoteins, phycoerythrin and the blue phycobiliproteins
and phycocyanin, are insoluble in water and can serve as natural
colorants in foods, cosmetics and pharmaceuticals. The algal pigments
have potential as natural colorants for use in food, cosmetics and
