The study of algae, called phycology or algology,
encompasses large and diverse groups of simple organisms
ranging from unicellular to multicellular forms. Many are
useful product sources for medicinal and nutritional
compounds. The largest algal seaweed forms are plant-like,
but lack distinct organs found in higher plants, such as leaves,
roots and vascular tissues. In Western countries seaweeds are
harvested for their soluble fibre, non-digestable
polysaccharides including agars, carrageenans and alginates
(Kirkwood, 1974). Natural carrageenan biopolymers are now
available as replacements for animal gelatins in the nutritional
supplement industry for softgel encapsulation (Source-Omega product innovations). With broad utility as thickening agents
for various industrial applications, seaweed polysaccharides
have also long been used in toothpastes, soaps, shampoos,
cosmetics, ice creams, processed foods and many other items
of commercial value. Yet seaweeds are still only beginning to
be used for their medicinal and chemical properties.
Though traditionally seaweeds are collected from
natural wild stocks, certain ecosystem resources are becoming
depleted or polluted, so cultivation techniques have been
developed as either open run ponds or enclosed bioreactors. In
general, culture harvests provide polysaccharides and dietary
fibers (both soluble and insoluble) that may constitute 35-60%
of dry weight, protein at 5-15% of dry weight and lipids at 1-
5% of dry weight, including fatty acids, carotenoids and
vitamins. In oriental countries such as Japan, China, Korea
and others, seaweeds are dietary superfood staples (Tab. 1). In
Japan, Porphyra tenera “Nori” and Palmaria palmate“Dulse”, for instance, are richer in protein content (35 - 47%
of dry weight) than even soybeans.
Table 1: Algae used for human consumption.
All true algae have a nucleus enclosed within a
membrane and have chloroplasts bound in one or more
membranes, which distinguishes them from nonphotosynthetic
protozoa. Like land plants, seaweeds have
distinct photosystem pigments and use carbon di-oxide, trace
nutrients and sunlight to make exclusive energy products de
novo. Unlike land plants, however, and particularly important
to human nutrition is the fact that essential long chain
polyunsaturated fatty acids (PUFAs) are made by algal species only, not by plants.
Of the two classes of essential long chain
polyunsaturated fatty acids (PUFA), called omega-6s and
omega-3s, only microalgae (phytoplankton) and macroalgae
(seaweeds) synthesize these polyunsaturated fatty acids
needed by the human body. Fundamentally, omega-6s
arachidonic acid (ARA) (C20:4 n-6) and docosapentaenoic
acid (DPA) (C22:5 n-6), especially the omega-3s
eicosapentaenoic acid (EPA) (C20:5 n-3) and
docosahexaenoic acid (DHA) (C22:6 n-3) are vital to brain
and organs through all stages of life. Since algae are the basis
of food chain for most marine ecosystems, mankind also has
the opportunity to utilize these source producers through
mariculture technologies. In recent years, variety of algal
species rich in PUFA have been screened using standard
methodologies and validated for their efficiency.
DHA as a drug candidate
Currently, difficulties in obtaining sufficient dietary
omega-3 docosahexaenoic acid (DHA) levels coupled with
inefficiencies in human omega-3 metabolism prevents alpha-linolenic acid (ALA) precursor omega-3 bioconversion
and subsequent docosahexaenoic acid (DHA) utilization at
levels necessary for medical treatments. Unless
docosahexaenoic acid is obtained directly from concentrated
supplement sources, dietary sources are not sufficient to deliver
a medicinal effect. Docosahexaenoic acid rich golden
microalgae oil qualifies as a source of slow cognitive decline
and onset of Alzheimer’s/dementia (Kalmijn et al., 1997; Lim
et al., 2005).
For measurable benefits in cholesterol tests, high dose
docosahexaenoic acid (DHA) treatments lower the high
triglyceride levels upto 10-20% within 3 months. Other areas
of importance include help in the diabetic dislipidemias and
protection against arrhythmia, atherosclerosis, high blood
pressure and other risk factors associated with cardiovascular
diseases (Mori and Woodman, 2006).
Since docosahexaenoic acid (DHA) is 90% of the
human body’s omega-3 content and 97% of the omega-3
content is in the brain, only edible algal oils can provide
docosahexaenoic acid (DHA) at the medicinal concentrations
needed to counter high fat dietary imbalances and omega-3
deficiencies. Worldwide measurements associated with modern dietary trends suggest that departure from traditional
fresh diets can lead to metabolic decline and deficiency in
docosahexaenoic acid (DHA) omega-3 levels. By harvesting
selective algal species for docosahexaenoic acid (DHA) and for
other food properties, the relatively untapped biodiversity of
the marine algal kingdom can help provide sustainable
medicinal omega-3 resources for our planet.
Bioinformatics can be used to probe the biodiversity
of algal resources. The validation of drug likenesses using
instructive in silico tools like Molinspiration
(www.molinspiration.com) for screening candidate compounds
against the Lipinski “Rule of 5” (Lipinski et al., 1997),
qualified docosahexaenoic acid (DHA) omega-3 as a potential
drug compound. The method demonstrates how predictive
chemical criteria mirrors functionality, where docosahexaenoic
acid’s (DHA’s) small molecule properties fit with its predefined
clinical benefits, making it a candidate for future
research and development. Notably, the medicinal and nutritional value of both arachidonic acid (ARA) and
docosahexaenoic acid (DHA) are important for human welfare.
Kalmijn, S., Launer, L. J., Ott, A., Witteman, J. C., Hofman, A.
and Breteler, M. M. (1997) Dietary fat intake and the
risk of incident dementia in the Rotterdam Study.
Ann. Neurol. 42 (5), 776-82.
Kirkwood, S. (1974) Unusual polysaccharides. Ann. Rev.
Biochem. 43: 401-17.
Lim, G., Calon, F., Morinara, T., Yang, F., Teter, B., Ubeda,
O., Salem N. Jr., Ashe, K. H., Frautschy, S. A. and
Cole, G. M. (2005) A diet enriched with the omega-3
fatty acid docosahexaenoic acid reduces amyloid
burden in an aged Alzheimer mouse model. J.
Neurosci. 25 (12), 3032-40.
Lipinski, C. A., Lombardo, F., Dominy B. W. and Feeney, P. J.
(1997) Experimental and computational approaches to
estimate solubility and permeability in drug discovery
and development settings. Adv.Drug Deliv. Rev. 23,
Mori, T. A. and Woodman, R. J. (2006) The independent effects of eicosapentaenoic acid and docosahexaenoic
acid on cardiovascular risk factors in humans. Curr.
Opin. Clin. Nutr. Metab. Care. 9, 95-104.
Microbes mutated in outer space become
far more dangerous
Salmonella typhimurium, a food poisoning
bacteria sent into outer space for 12 days by
researchers responded to the altered gravity
(microgravity conditions) by becoming more
virulent with changed expression of 167 different
genes. The finding may be significant not only for
those who travel in space, but also in terms of
microbes astronauts are bringing back.
CENTRE Newsletter Vol.7,Issue 4 October 2009