Home Health Seaweeds are not only for eating

Seaweeds are not only for eating


Text and Photos by Henrylito D. Tacio

For every 100,000 Filipinos, some 189 people are afflicted with cancer, while four die of cancer every hour. That’s according to a study conducted by the Institute of Human Genetics of the University of the Philippines.

Based on recent data released by the Department of Health and the Philippine Cancer Society, Inc., nine Filipinos are diagnosed with cancer every hour.

The good news is: President Rodrigo R. Duterte recently signed Republic Act 11215 or the National Integrated Cancer Control Act. The new law pursues a national framework to fight cancer.

A few days after the president enacted the law, the Department of Science and Technology (DOST) released the findings of a study which said that a certain species of seaweed thriving in the country’s water may have anti-cancer benefits.

“Researchers from the University of Santo Tomas found that polysaccharides extracted from Codium species, locally known as ‘pukpuklo’ (a seasonally-available seaweed), are effective against cancer cells and destructive enzymes associated with cancer metastasis,” said a press statement released by DOST.

The researchers, headed by Dr. Ross Dizon Vasquez, evaluated the inhibitory potential of the polysaccharides fractions isolated from Codium species. They found that “the seaweed fights destructive enzymes that aid metastasis or spread of cancer to different parts of the body.”

Polysaccharides are carbohydrates such as starch, cellulose, or glycogen whose molecules consist of a number of sugar molecules bonded together. This kind of carbohydrates is used by the body in storing energy, sending cellular messages, or for providing support to cells and tissues.

Delicious seaweeds

The Codium species used in the study were collected in Ilocos Norte, Aklan, Iloilo, and Cagayan province.

“Pukpuklo,” a favorite Ilokano dish, is known as a good source of dietary fiber, amino acids, and minerals. However, little is known about its medicinal value, and further studies have yet to be conducted to explore its use in the field of medicine.

Last year, medical research was also in the limelight when Dr. Annabelle V. Briones shared her study showing the possibility of carrageenan as a valuable agent in gene delivery/therapy. 

Carrageenan is an indigestible carbohydrate extracted from edible seaweeds. In her study, Dr. Briones used those extracted from red seaweeds (particularly the Eucheuma variety).

Gene therapy is a method of introducing new genetic material (DNA) into the diseased cells of an individual with the intention of producing therapeutic benefits for the patient. This kind of therapy has been around for decades, but scientists have seen little success with this technology because gene transfer is a very delicate and complicated process.

In her study, Dr. Briones found that carrageenan, specifically the iota type, may be used as a potential gene delivery vehicle when it was tested as a “coating” material for DNA in cultured cells (in vitro).

According to her, the coating made from the iota carrageenan was able to protect the DNA as it remains stable and viable during the gene transfer process. She added that the iota carrageenan has the highest transfection efficiency compared to the other two types of carrageenan, the kappa, and the lambda.

The iota carrageenan has the “best release capability” of the DNA material into the target cells, said Dr. Briones, who was given an Achievement Award (Chemical Sciences Division) by the National Research Council of the Philippines in 2016.

But it’s not only in medical science that seaweeds find their other purpose. Even in agriculture, they can be of great help. Scientists from the National Crop Protection Center at the University of the Philippines Los Baños (UPLB), with innovative technology, found that seaweed extracts can boost rice yield by more than 65%.

This is good news for Filipinos since rice is a staple food. About 89% of the country’s total population of more than 100 million consume rice on a daily basis.

Some studies showed that when carbohydrate from carrageenan is reduced to tiny sizes by a safe technology process called irradiation, it can be an effective growth promoter and makes rice resistant to major pests. In fact, at very small doses, it is an effective organic fertilizer.

“As a growth enhancer, it offers an array of benefits that result in improved productivity,” the UPLB researchers said. “Used properly as prescribed, it makes the rice stem stronger thus improving rice resistance to lodging.”

But what made the seaweed extracts valuable is that it also promotes resistance to the rice ‘tungro’ virus and bacterial leaf blight, two of the worst problems rice farmers have to face. As a result, farmers can obtain increased harvest.

“This seaweed additive is that it is compatible with the traditional practice on fertilizer application, thereby allowing easy acceptance and less resistance from farmers,” explained the press statement. “It also promotes sustainable agriculture since it is environment-friendly and enhances the presence of natural enemies that fight major pests in rice fields.”

More importantly, the technique promotes more efficient absorption of plant nutrients that enables improved growth.

In a field trial conducted in Bulacan by the research team using carrageenan, rice yield was significantly increased by 63.6 – 65.4%. “This treatment provided higher grain weight (of 450 grams and 455 grams, respectively) compared to traditional farmers’ practice of applying nine (9) bags of fertilizer per hectare that yielded only 275 grams,” the study found.

Application of six bags of fertilizer per hectare plus 200 parts per million (or 20 milliliters) of carrageenan is more or less comparable with the application of just three bags of fertilizer per hectare with the same mixture.

“This innovation of applying seaweed as fertilizer empowers our farmers to have access to cheaper but highly effective plant growth enhancers that boils down to improved harvest and increased income,” the press statement said.

Seaweeds are marine plants that grow abundantly in shallow reef flats and in lagoons with a water depth of less than two meters at high tide. They differ from plants because they lack the stems, leaves, roots, and vascular systems that are common in higher plants.

Technically, seaweeds are “multicellular” forms of algae and are classified into three main divisions: brown algae, red algae, and green algae. Brown algae, commonly called “kelp,” are the largest variety. Pacific species can reach 65 meters in length and have structures that superficially resemble leaves and stems.

On the other hand, red algae are composed of several species, including the Irish moss. They are abundant in clear tropical waters. Meanwhile, green algae – which are sometimes called “sea lettuce” – are commonly seen at low tide along rocky shores in northern seas.

The Philippines is one of the pioneers in seaweed farming. Cultures of PorphyraEucheuma, and Caulerpa in the Philippine marine farms have been recorded as early as the 1960s. Through the initiative of Dr. Max Doty, a marine botanist at the University of Hawaii, and his local counterparts, the first technology for the culture of Eucheuma was introduced to the industry in 1973.

Commercial seaweed farmers first succeeded in cultivating Eucheuma in the reef areas of Mindoro, Aklan, Cuyo, Zamboanga, and Tawi-Tawi. Since then, seaweed production has gone overboard.

Ideally, the conditions for growing the seaweeds are water depths of one foot to two feet at low tide, water temperature of 27 to 30 degrees Centigrade, the salinity of 31 to 34 parts per thousand, and moderate water movement (20 to 40 meters per hour). Excessive sunlight, strong currents, and the presence of plant-eating fish like danggit (siganid) can be detrimental to seaweed growing.

In the Philippines, some 390 species have been identified as having economic value as food, animal feeds, fertilizers, diet supplement, medicines, and raw materials for industrial products.

At least 60 Philippine varieties are reportedly edible, including “gulamang dagat,” “gamet,” “pocpoclo,” “culot,” “lato,” “guso,” “barls-barls,” “bulaklak bato,” and “balbalolang.” Some of these varieties can be processed into jams, jellies, candies, pickles, baby’s food, and “gulaman” bars.

The food value of seaweeds varies in different species. Average chemical analyses of 46 species of marine algae in the Philippines show that the crude protein content (percentage of dry weight) is 7.44, 6.40, and 9.29 for the green, brown, and red seaweeds, respectively. This is about two to three times the protein content of common green leafy vegetables, which is 3.27 percent dry weight.

Four species – Halimada, Hypnea, Sargassum, and Asparagopsis – have been used as feed or fodder for livestock. Species of Cladophora, Enteromorpha, Chaetomorpha, and Gracilaria are used to supplement or substitute for fish food for cultured herbivorous fish.

Seaweeds also have some medicinal values. They are used to treat or prevent goiter, glandular troubles, stomach disorders, intestinal and bladder difficulties, unusually profuse menstrual flow, high blood pressure, and high plasma cholesterol level. Gracilaria species are used locally as pain relievers and ointments.

Commercially, seaweeds are valued for their colloids or gluey substance, particularly agar, carrageenan, and algin. Both agar and carrageenan are extracted from red seaweeds, while algin is extracted from brown seaweeds.

Agar, which derived its name from the Malay word for seaweed, “agar-agar,” is used in making jellied desserts, as a stabilizer in pie fillings, piping gels, icings, cookies, cream shells, and as a thickening and gelling agent in poultry, fish and meat canning.

In the medical and pharmaceutical industries, agar serves as a laxative, suspending agent for barium sulfate in radiology, ingredient for slow-release capsules and in suppositories and surgical lubricants, and as a disintegrating agent in tablets. It is also used as impression materials to make accurate casts in prosthetic dentistry, criminology, and tool manufacturing.

Carrageenan, on the other hand, is used in making ointments, as a stabilizing agent in frozen dairy products, as an emulsifying agent in water-insoluble drugs and herbicides, and as a texturing agent in toothpaste and powder. The Philippines is the world’s top carrageenan exporter.

Algin or alginic acid, meanwhile, is used as another stabilizing agent for several food products, as a sizing agent in paper manufacture, and as a thickening agent in print pastes and painting coatings. 

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