Jiang, Zheng Yi
(College of Bioengineering, Fujian Normal University, Fuzhou, Fujian 350007)
In this paper, the pharmacological active substances in microalgae, the medicinal and health value of microalgae products that have been put into the market, and the research and development status of microalgae health care and functional food are reviewed.
Keywords: microalgae; Pharmacologically active substances; Health care and functional food
China library classification number: Q949.2S986.2 document identification number: document number:1009-7791(2003) 01-0068-05.
There are more than 30,000 different kinds of microalgae on the earth, which are distributed in fresh water and oceans and also exist in various soils (including hot summer and cold and barren environment). For a long time, people only regard microalgae as direct or indirect live bait for fish, shrimp, shellfish larvae or adults. In recent decades, people have paid more and more attention to the research and development of bioactive substances from microalgae. Microalgae are rich in bioactive substances with unique structure, many of which have pharmacological activities and have great potential in the development and application of medical and health products. At present, the application of microalgae and microalgae products in pharmaceutical industry is gradually attracting people's attention.
Pharmacological active substances in 1 microalgae and their efficacy
1. 1 antibiotics
Antibiotics are antimicrobial compounds naturally produced by organisms that are toxic to microalgae, bacteria, fungi, viruses or protozoa. Most antibiotics produced by microalgae have not been clearly identified. Known antibiotics are fatty acids, other organic acids, bromophenol, phenol inhibitors, tannins, terpenoids, polysaccharides, other carbohydrates and phenols. Pratt and others were the first researchers to isolate antibiotics from microalgae. They isolated a fatty acid mixture containing chlorophyllin from microalgae, which has antibacterial and autotoxic effects. Pesando proved that the photooxidation products of eicosapentaenoic acid from diatom (Stemona) have strong antibacterial activity. Sieburth proved that acrylic acid synthesized by Chlorella is an antibacterial compound. Subsequently, some scholars screened a variety of species with antibacterial activity from microalgae, and some effective components have been identified, such as cyanobacteria in Bifidobacterium Netherlands, 2,5-dimethyldodecanoic acid in Oedogonium estuarine, indole alkaloids in Cephalosporium, phenolic compounds in Auricularia auricula and sterols in Spirulina gigantea, which are all effective anti-biomass.
1.2 toxin
Toxins produced by microalgae can cause paralysis, dysentery, botulism and hemolytic poisoning in animals and humans through fish, shrimp, crabs and shellfish. Therefore, these toxins can be divided into: (1) paralytic toxins (PSP), which are produced by several dinoflagellates in dinoflagellate and Phaeocystis in Cyanophyta, and one of them is sarcophagus toxin, which can be prevented. (2) Dysentery toxin, which is produced by some algae in Anoplophora obovata, is also called Anoplophora obovata toxin (DTX). This compound can cause symptoms of diarrhea, vomiting, exhalation and abdominal pain, also known as "diarrhea shellfish poisoning"; (3) Botulinum toxin (CTX), which is produced by Gambierdiscus toxiclls. The toxin acts on sympathetic nerve fibers and can improve the permeability of cell membrane to Na+. (4) Hemolytic toxin, produced by Chlorella, has strong hemolytic effect. Among them, tachytoxin (BTX), also called neurotoxin, produced by Chaetobacter Cardenii also has hemolytic effect.
Most toxins produced by microalgae are based on their highly specific effects on biological nervous system or cardiovascular system. Therefore, these toxins and their mechanisms of action are important guiding compounds and clues for the development of drugs for nervous system or cardiovascular system, and their applications in medicine and physiology are under study.
1.3 Cardiovascular and cerebrovascular active substances
Polyunsaturated fatty acids rich in microalgae have many pharmacological effects, among which DHA (C22: 6) can be used to prevent and treat atherosclerosis, coronary heart disease, vasodilation, anti-platelet aggregation and anti-thrombosis caused by hyperlipidemia. Porphyridium is rich in arachidonic acid, while Spirulina contains more linoleic acid and linolenic acid. In addition, carotenoids and carotenoids rich in microalgae have certain preventive and therapeutic effects on cardiovascular and cerebrovascular diseases.
1.4 anti-tumor, anti-radiation and anti-mutation active substances
Screening antitumor substances from algae and microalgae began at 1977, and cyanobacteria are an important source of effective anticancer drugs. It has long been found that the fat-soluble extract of Oedogonium giganteum has anti-leukemia activity. As early as 198 1 year, Moore tested the pharmacological activities of cyanobacteria extracts. Up to now, 67 strains of cyanobacteria with anti-tumor activity have been found from more than 1000 species of cyanobacteria, and compounds with unique structures of 12 have been identified. In addition, Prodinolactone in flagellate, glycoprotein in Chlorella and scenedesmus, and L- asparaginase in Chlamydomonas. All have anti-tumor activity. In addition, spirulina phycocyanin has a good anti-radiation effect, which can improve the production of granulocyte colony stimulating cells (CFU-GM) and obviously improve the colony stimulating activity of normal mouse serum. Polysaccharide from Spirulina platensis can significantly enhance the DNA damage caused by radiation and the excision and repair of DNA unscheduled synthesis (UDS), and also has a certain antimutagenic effect.
1.5 Active substances for enhancing immunity and fighting AIDS
Studies have shown that spirulina polysaccharide can comprehensively regulate the immune function of the body and enhance the nonspecific immunity, humoral immunity and cellular immunity of the body. At the same time, it can also eliminate or alleviate the inhibitory effect of cyclophosphamide on the immune system of the body. Phycocyanin (C-PC) can obviously enhance the immune activity of spleen lymphocytes in mice. In the screening of anti-AIDS active substances, it was found that Schizophyllum pacificum sulfate polysaccharide SAE is a specific virus reverse transcriptase inhibitor, which can inhibit not only HIV reverse transcriptase, but also other viruses. In addition, the sulfur-containing glycolipid extracted from Sphaerocyte can inhibit the replication of HIV, and has been approved by NCL (National Cancer Institute) for preclinical pharmacological and toxicological research. The structure and biological activity of thioester have been confirmed by chemical synthesis and biological detection.
Medicinal and health care value of several microalgae products
Because microalgae contain a variety of pharmacological active substances, people have developed and extracted a variety of useful and health-care components from microalgae. The following are some microalgae products that have been developed into products and entered the market with medicinal and health care values.
2. 1 phycobiliprotein
Phycobiliprotein is a water-soluble protein, which can be divided into phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (A-PC). At present, it is found that phycocyanin has certain medical value and can promote the immune system to improve its ability to resist various diseases. At the same time, spirulina phycocyanin also has inhibitory effect on some cancer cells. Morcos et al. and Cai et al. proved that phycocyanin has photosensitive effect and good anticancer effect; Zhang Chengwu proposed that phycocyanin can stimulate bone marrow hematopoiesis, and can be used for clinical adjuvant treatment of various blood diseases. Phycobiliprotein has the characteristics of stable properties, high fluorescence quantum yield, low background interference and easy cross-linking with biotin antibodies, glycoproteins and other macromolecules. As a new generation of fluorescent probes, it can replace isotopes and enzymes as markers for clinical diagnosis, immunology, cell biology, histochemistry and molecular biology. Phycobiliprotein has a very broad potential market, and many foreign companies have invested in the development of phycobiliprotein, and the product price is above 100 USD /mg.
2.2 β -carotene
Under certain conditions, Dunaliella salina can accumulate a large amount of β-carotene, and its content can reach about 10% of the dry weight, ranking first among all living things in nature. β -carotene is not only the precursor of vitamin A, but also a large number of experiments have proved that β -carotene has a strong inhibitory effect on tumor transformation, which can reduce the canceration induced by ultraviolet rays and chemical tumor promoters. β -carotene has a strong quenching effect on free radicals and can reduce the damage of peroxide to tissues. β -carotene can promote the function of phagocytes and lymphocytes, and promote cells to release some anti-tumor factors. Beta-carrots also have some protective effects on cataracts, macular degeneration and cardiovascular diseases.
β -carotene extracted from Dunaliella salina is a high-value commodity. Many manufacturers in Australia, the United States and Israel produce β -carotene at a price as high as $600/kg.
2.3 Astaxanthin (Asta, also known as Super Vitamin E)
Astaxanthin belongs to carotenoids, which has strong antioxidant function, can remove free radicals produced by ultraviolet radiation in the body, adjust and reduce the damage caused by photochemistry, and has a good therapeutic effect on skin cancer caused by ultraviolet radiation and ASTA；; Astaxanthin (super vitamin E) has higher antioxidant function than other carotenoids, and can inhibit the oxidation of biofilm. Astaxanthin (super vitamin E) can also significantly promote the production of lymph node antibodies, especially those related to T cells in vivo.
Astaxanthin has a wide range of uses, and its output is far below the market demand, and the price is 300 US dollars/kg. Haematococcus pluvialis can accumulate astaxanthin accounting for more than 65438 0% of dry weight under certain conditions, which is a natural source of pigment.
2.4 polyunsaturated fatty acids
The research on the production of polyunsaturated fatty acids by microalgae culture began in the early 1980 s, and polyunsaturated fatty acids have important physiological and health care functions for human body. Omega-3 polyunsaturated fatty acids are closely related to reducing blood lipid and the incidence of heart disease, and can also improve burn symptoms and reduce sepsis, and have the functions of anti-aging, improving memory of the elderly, organ transplantation and so on. It can replace non-steroidal anti-inflammatory drugs to treat immune abnormal diseases. Among them, DHA has the following physiological functions: (1) prevention and treatment of cardiovascular diseases. DHA in mammals is mainly used to synthesize prostaglandin, which can reduce prostaglandin A2, increase prostacyclin content, reduce vascular resistance, reduce blood viscosity and reduce platelet aggregation and adhesion. (2) Prevention and treatment of cancer. Japanese scholars found that the incidence of breast cancer, colorectal cancer and lung cancer in mice fed DHA was very low, so it was inferred that DHA was related to the prevention and treatment of cancer. (3) Regulating the function of the central nervous system. DHA mainly exists in the gray matter of the brain and is an important component of omega-3 polyunsaturated fatty acids in the human brain. The decrease of DHA content in the brain can lead to the decline of learning and memory ability; (4) Regulation of visual system, DHA is an important component of retinal tissue. If DHA content in retina decreases, electroretinogram will be abnormal.
Although fish oil is the main source of EPA and DHA, its stable supply is limited and its quality is unstable, and cultured microalgae is a reliable source of such fatty acids. At present, the price of DHA in the market is 140 USD/gram, and EPA is as high as 2000 USD/gram.
3 microalgae health functional food and its research and development status
Nowadays, health has become the theme of food development. At present, the focus and development trend of food research have focused on the research and development of health food and functional food. The so-called health functional food refers to the food that not only has the nutrition, color, smell, taste and characteristics of ordinary food, but also has obvious promotion effect on human physique, immunity and metabolism. Spirulina and Chlorella have been successfully developed. Edible microalgae such as spirulina and Chlorella are rich in protein, vitamins, biological polysaccharides, polyunsaturated fatty acids, chlorophyll, carotenoids and minerals, so they have excellent nutritional and health care functions. Spirulina has the functions of preventing cancer, inhibiting cancer, enhancing immunity and resisting aging. At the same time, it also has obvious effects on treating hypertension and gastric and duodenal ulcers, lowering cholesterol and avoiding atherosclerosis, anemia, hepatitis and diabetes. Chlorella is also effective in treating gastric ulcer, trauma, anemia, hepatitis, diabetes, infant malnutrition, psychosis, cancer, etc. It also has the effects of activating skin cells, accelerating metabolism and delaying cell aging. Spirulina and Chlorella occupy an important position in the health food market in Japan and the United States. In 1960s, there was an upsurge of Chlorella culture in China. In recent years, microalgae food, mainly spirulina, occupies a certain position in more than 3000 kinds of health food. There are many forms of microalgae health care and functional food. Here are two kinds of products with good health care performance and large market sales.
3. 1 microalgae health tablets and capsules
Microalgae health tablets (or capsules) can keep the nutrients and bioactive components of algae, so they have always been in a dominant position in the microalgae health food market. In 1970s, Japan, the United States and European countries first developed Chlorella, Spirulina and Dunaliella slice (or capsule) health food, and realized large-scale production and sales. China Yunan Spirulina Spirulina Capsule is the only microalgae health care drug in China that has won the title of pharmaceutical grade. In addition, microalgae health products include spirulina tablets, a rare Guangdong treasure, and spirulina tablets, a star health product.
3.2 Microalgae extract (nutrient solution)
Studies have proved that Chlorella cells contain a bioactive component called chlorophyll, which can improve human immunity and have health care functions. Spirulina cells and its hot water extract also have the effects of strengthening body, losing weight, building body, and preventing and treating diseases. At present, the international sales of strong green algae essence and honey green algae essence produced in Japan are relatively large. In China, Wuhan Institute of Botany of China Academy of Sciences cooperated with Wuhan Pharmaceutical Factory to develop spirulina oral liquid, and South China University of Technology cooperated with Guangdong Maoyuan Import and Export Corporation to develop spirulina health-care nutrient solution.
4 outlook
The unique pharmacological active substances contained in microalgae make microalgae have a variety of medicinal and health-care properties, and there is great potential to develop new drugs and health-care and functional foods by using microalgae. In the research and development of drugs, Pulz thinks that cyanobacteria are the most promising, which have the functions of immune promotion, anti-tumor or cytoplasmic stability. Some natural products of microalgae, such as sharmycin, may be listed as drugs. Microalgae also have the characteristics of fast growth, long cycle and strong plasticity, and are easy to breed in large quantities. However, the development of microalgae resources needs to solve several problems: (1) cost. In order to reduce the cost, it is necessary to develop algae biomass from the health care product market into a commodity and make it competitive in price; (2) Training. It is necessary to further develop suitable reactors, such as anti-pollution closed system, easy-to-maintain pure algae culture, good temperature control and high cell density, to ensure high yield; (3) Improvement of algae species. In order to make algae biotechnology economically active, it is necessary to cultivate algae strains that can meet various purposes and adapt to various culture environments, and use more kinds of microalgae. With the gradual maturity of biotechnology in the study of algae bioactive substances, it is believed that in the near future, extracting active products from microalgae will become the pillar of modern medicine and health food industry.