Algae Therapeutic Compounds — Carotenoids and Fucoidan
by Dr. Mark Edwards
lgae have served as food for plants and animals for over 2 billion years. The cellular metabolism of plants and animals evolved to take advantage of the many compounds algae provided. Today, wild stands of algae, largely seaweeds, are harvested in oceans and estuaries. The active compounds are extracted for use in food, feed, fertilizer, advanced compounds, pharmaceuticals and medicines. Tomorrow, algapreneurs will cultivate both macro and micro algae in order to produce large quantities of high-quality compounds.
Natural stand harvests pose several challenges. Seaweeds grow near coasts where considerable pollution degrades the quality of algae compounds or adds the cost of cleaning contaminants from harvested biomass. Algae bioaccumulate some heavy metals at 1,000 times ambient rates, which results in high levels of iodine, arsenic, mercury and lead. Algae cultivation can minimize or eliminate contaminants in the algae culture, producing clean, high quality medical compounds.
Seaweeds grow naturally in the ocean but farming can increase productivity by a factor of 10 or higher. Farmers can optimize at the critical factors for growth, including photons, nutrients, temperature, pH and mixing. Algae cultivation systems, microfarms, can be designed to maximize the efficiencies of biomass harvest and compound extraction.
Carotenoids are organic pigments found in the chloroplasts and chromoplasts of photosynthetic organisms such as land plants and algae. Chromoplasts are the organelle responsible for a plant’s distinctive color, which comes from the accumulation of carotenoid pigments. Carotenoids cannot be synthesized by animals but are essential as they serve as building blocks for cellular metabolism. Animals obtain carotenoids from their diets.
Over 600 carotenoids are found in nature, but only six are present in the human bloodstream and only three – lutein, zeaxanthin and meson-zeaxanthin – are found in the human eye’s macula. These three carotenoids accumulate in the macula at a concentration 10,000 times that found in the blood stream. The biochemical characteristics of lutein provide important structural components in cell membranes and act as a short-wave-length filter.
Carotenoids are divided into two classes, xanthophylls that contain oxygen, and carotenes that do not contain oxygen, and are purely hydrocarbons. Carotenoids serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect chlorophyll from photo damage. Algae use carotenoids to make retinal, (provitamin A) which allows the plant to convert light into metabolic energy.
In humans, carotenoids deposit in the macula and are vital in protecting the retina photoreceptors and retina pigment epithelium from harmful damage by ultra-violet and blue wavelength light sources. Carotenoids also enhance vision by decreasing chromatic aberration and photosentivity. These compounds improve glare recovery time and contrast sensitivity in vision acuity through a reduction in blue-light scatter.
Antioxidants protect human health with compounds that inhibit the oxidation of other molecules. They act as a modulator of redox, (reduction-oxidation) and a modulator in signal transduction pathways. Oxidation transfers electrons or hydrogen from a substance to an oxidizing agent, which often produces free radicals. Free radicals can start chain reactions that damage or kill cells. Antioxidants terminate these chain reactions by removing free radical intermediates, and prevent other oxidation reactions. Carotenoids enhance the immune system because they are efficient free-radical scavengers.
Four carotenoids act as antioxidants in humans, beta-carotene, alpha-carotene, gamma-carotene and beta-cryptoxanthin. They operate singularly or in concert to synthesize retinal, which is critical for eyesight. Other carotenoids such as lutein and zeaxanthin also help eyesight by absorbing damaging blue and near-ultraviolet light. Light absorption protects the macula of the retina, which is critical for sharp vision. Diabetics often have vision problems that may be related to their inability to produce sufficient retinal. People consuming diets rich in carotenoids are healthier and have lower mortality from a broad array of chronic illnesses, including diabetes.
Antioxidants such as beta-carotene can moderate blood sugar levels in pre-diabetics and diabetics. Antioxidants may help return blood sugar levels to their normal range in diabetes patients. Evidence suggests that the antioxidants selenium, zinc, vitamin E, vitamin B-6 and biotin help control blood sugar.
The best-known carotenoid, carotene, give carrots their bright orange color. The pink color of flamingos and salmon, and the red coloring of cooked shrimp and lobsters come from carotenoids. Flamingos, salmon, shrimp and lobsters get their pigments from algae or algae eaters. Each ounce of algae contains eight times the carotene provided by an ounce of carrots.
Epidemiologic evidence suggests that carotenoids are potent antioxidants and play a protective role in the development of chronic diseases including cancers, diabetes, cardiovascular disease and other inflammatory diseases. The role of antioxidants in the pathogenesis of diabetes mellitus may be related to the anti-inflammatory effects and the ability to reduce oxidative stress. Randomized human trials in a series of studies showed that serum carotenoids are inversely associated with type-2 diabetes and impaired glucose metabolism. Currently, it is unclear whether the biological effects of carotenoids in humans are a result of their antioxidant activity or other non-antioxidant mechanisms.
The Third National Health and Nutrition Examination Survey, (1988–1994), examined 8,808 U.S. adults aged over 20 years with and without the metabolic syndrome. People with the metabolic syndrome had lower carotenoid levels, which was probably due to their lower consumption of fruits and vegetables. Adults with the metabolic syndrome had suboptimal concentrations of several antioxidants, which partially explain their increased risk for diabetes and cardiovascular disease.
The carotenoid lycopene acts as both an anti-inflammatory and antioxidant. It has been found to be effective in the inhibition of angiotensin-converting enzyme, ACE activity, an important indicator of diabetes-related complications.
Brown seaweed, such as kelp, contain fucoidan and fucoxanthin. Fucoxanthin and fucoidan act together to help the macroalgae transform sunlight into energy. Fucoidan is a complex carbohydrate called a sulfated polysaccharide. Like alginates, focoidans offer remarkable effects in moisturizing. The compound lowers blood fat, which offers therapeutic treatments for obesity and diabetes. Fucoidan fractions significantly reduced blood glucose levels in diabetic mice.
The nutritional value of fucoidan stems largely from its native environment – the sea. Fucoidan is rich in calcium, iodine, zinc, iron, selenium and vitamin A. These nutrients are essential for proper functioning of the immune, circulatory and neurologic systems. Research shows fucoidans possess anti-cancer and anti-clotting effects. It relieves joint pain and provides support for the liver, cardiac function and digestion. Fucoidan enhances skin moisture and pliability, helps maintain healthy cholesterol levels and enhances cellular protection and regeneration. The mechanism seems to be that fucoidan facilitates improved cell signaling.
Fucoidan offers a therapeutic aid to control or reduce obesity due to bioactive compounds that are similar to dietary phytochemicals. Fucoidan exerts anti-obesity effects through the inhibition of inflammatory-related cytokines, (signaling molecules). Fucoidan also reduces the accumulation of lipids and reactive oxygen species production in adipocytes, the specialized cells that store fat.
Focoidans are used to treat nephrotic syndrome and nephritis that occur commonly in diabetics. Nephrotic syndrome is a group of symptoms associated with kidney disorders that pass too much protein in the urine, which causes low blood protein levels, high cholesterol, high triglyceride and swelling. Fucoidans improve kidney function and moderate symptoms in diabetics.
Fucoidans are used as anticoagulants, antivirals and in anti-tumor therapies. Fucoidans have been shown to resist HIV virus. These bioactive compounds have potent anti-HIV-1 activity both against WT and drug-resistant HIV-1 strains. The therapeutic mechanism seems to be that the fucoidans effectively block early events of viral replication.
Diabetics often find their kidneys do not function properly because they do not filter waste effectively. Leaky kidneys cause creatinine to accumulate in the blood. Fucoidans offer a treatment for nephrotic syndrome and early, medium or chronic renal failure with non-toxic side effects. The natural compounds improve renal function and lowering serum creatinine.
Growing algae to harvest carotenoids and fucoidan present an excellent business model for algae producers. Carotenoids and fucoidan are most likely to be coproducts for algae businesses growing algae for food, feed, nutraceuticals or other applications.