Sea cucumbers, belonging to the class Holothuroidea, are marine invertebrates, habitually found in the benthic areas and deep seas across the world. They have high commercial value coupled with increasing global production and trade. Sea cucumbers, informally named as beche-de-mer, or gamat, have long been used for food and folk medicine in the communities of Asia and Middle East. Nutritionally, sea cucumbers have an impressive profile of valuable nutrients such as Vitamin A, Vitamin B1 (thiamine), Vitamin B2 (riboflavin), Vitamin B3 (niacin), and minerals, especially calcium, magnesium, iron and zinc. A number of unique biological and pharmacological activities including anti-angiogenic, anticancer, anticoagulant, anti-hypertension, anti-inflammatory, antimicrobial, antioxidant, antithrombotic, antitumor and wound healing have been ascribed to various species of sea cucumbers. Therapeutic properties and medicinal benefits of sea cucumbers can be linked to the presence of a wide array of bioactives especially triterpene glycosides (saponins), chondroitin sulfates, glycosaminoglycan (GAGs), sulfated polysaccharides, sterols (glycosides and sulfates), phenolics, cerberosides, lectins, peptides, glycoprotein, glycosphingolipids and essential fatty acids. This review is mainly designed to cover the high-value components and bioactives as well as the multiple biological and therapeutic properties of sea cucumbers with regard to exploring their potential uses for functional foods and nutraceuticals.

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High-Value Components and Bioactives from Sea Cucumbers for Functional Foods—A Review

1. The effects of the volatile oil (V.O.) of the black seed ( Nigella sativa ) on the arterial blood pressure and heart of urethane-anaesthetized rats were investigated and the effects were compared with those of its constituent thymoquinone (T.Q.). 2. Intravenous administration of V.O. in the dose range (4–32 μl kg. −1 ) or T.Q. (0.2–1.6 mg kg −1 ) to rats decreased the arterial blood pressure and the heart rate in a dose-dependent manner. 3. The effects of V.O. were significantly antagonized by treatment of the animals with cyproheptadine, hexamethonium atropine and by spinal pithing. 4. Treatment of the animals with reserpine (5 mg kg − 1 day −1 for 2 days) significantly antagonized the cardiovascular depressant effects induced by 4 and 8 μl of V.O. kg −1 but not those induced by the larger doses. 5. T.Q.-induced cardiovascular depressant effects were significantly antagonized by atropine and cyproheptadine but not by reserpine. 6. The results suggested that V.O.-induced cardiovascular depressant effects were mediated mainly centrally via indirect and direct mechanisms that involved both 5-hydroxytryptaminergic and muscarinic mechanisms. The direct mechanisms may be due to the presence of T.Q. in the V.O. The V.O. seemed to possess the potential of being a potent centrally acting antihypertensive agent.

The cardiovascular actions of the volatile oil of the black seed (Nigella sativa) in rats: elucidation of the mechanism of action

One of the most intensively studied holothurians, Holothuria scabra has been discussed in the literature since 1833. The species is important for several reasons: (1) it is abundant and widely distributed in shallow soft-bottom habitats throughout the Indo-Pacific; (2) it has a high value on the Asian markets, where it is mainly sold as beche-de-mer; and (3) it is the only tropical holothurian species that can currently be mass produced in hatcheries. Research on H. scabra continues but because of commercial exploitation, wild stocks are declining. This review compiles data from 14 these and 352 technical reports and scientific papers pertaining to the biology, ecology, aquaculture and fisheries of H. scabra . Although several references are likely to have been missed by our investigation, we present the most complete reference list to date, including obscure material published by local institutions and/or in foreign languages. Our main aim was to summarize and critically discuss the abundant literature on this species, making it more readily accessible to all those wishing to conduct fundamental research, or aquaculture and stock enhancement programmes, on H. scabra across its entire geographic range.

The sea cucumber Holothuria scabra (Holothuroidea : Echinodermata) : Its biology and exploitation as beche-de-mer

Antibacterial activity in Strongylocentrotus droebachiensis (Echinoidea), Cucumaria frondosa (Holothuroidea), and Asterias rubens (Asteroidea).

Wound healing is a complex process of recovering the forms and functions of injured tissues. The process is tightly regulated by multiple growth factors and cytokines released at the wound site. Any alterations that disrupt the healing processes would worsen the tissue damage and prolong repair process. Various conditions may contribute to impaired wound healing, including infections, underlying diseases and medications. Numerous studies on the potential of natural products with anti-inflammatory, antioxidant, antibacterial and pro-collagen synthesis properties as wound healing agents have been performed. Their medicinal properties can be contributed by the content of bioactive phytochemical constituents such as alkaloids, essential oils, flavonoids, tannins, saponins, and phenolic compounds in the natural products. This review highlights the in vitro, in vivo and clinical studies on wound healing promotions by the selected natural products and the mechanisms involved.

https://www.mdpi.com/1660-4601/15/11/2360/pdf

Wound Healing Properties of Selected Natural Products.

Fatty acid profile from crude extracts of local sea cucumber Stichopus chloronotus was determined using gas chromatography (GC) technique. The extracts were prepared separately in methanol, ethanol, phosphate buffer saline (PBS), and distilled water as part of our study to look at the affinity of these solvents in extracting the lipid from sea cucumber. The PBS and distilled water extractions indicate water-soluble components, while the organic fractions are extracted in methanol and ethanol as organic solvents. Furthermore, water extraction is the conventional method practiced in Malaysia. In our analysis the C14:0 (myristic), C16:0 (palmitic), C18:0 (stearic), C18:2 (linoleic), C20:0 (arachidic), and C20:5 (eicosapentaenoic, EPA) were significantly different (p < 0.01) in the four solvent extractions. However, the PBS extraction contained a much higher percentage of EPA (25.69%) compared to 18.89% in ethanol, 7.84% in distilled water, and only 5.83% in methanol, and variances were significantly different (p < 0.01). On the other hand, C22:6 (docosahexaenoic acid or DHA) is much higher in water extraction (57.55%), in comparison to the others where only 3.63% in PBS and 1.20 % in methanol, and this difference is significant at p < 0.01. No DHA was detected in ethanol extractions. Subsequently, C18:1 (oleic acid) was only detected in PBS (21.98%) and water extraction (7.50%). It is interesting that palmitic acid, C16:0 was higher in methanol (20.82%) and ethanol (20.18%), while 12.55% was detected in PBS and only 2.20% in water extraction; and again this was significantly different at p < 0.01. Although our results have shown that all four solvents were different in terms of their ability to extract fatty acids, the major component for tissue repair was well preserved. Probably this is one of the important precocious steps when working with a delicate sea cucumber, in both experimental and/or at the preparative stages. Freshness of the sea cucumber samples is important when undertaking this type of experiment. Finally, we believe that the local sea cucumber S. chloronotus contains all the fatty acids required to play a potential active role in tissue repair.

Fatty acid compositions in local sea cucumber, Stichopus chloronotus, for wound healing.

1. Three species of sea cucumbers found in the Sabah coastal areas were screened for the presence of antibacterial activity using three methods of extraction. Tests were conducted in vitro using the agar absorption method. 2. Both the lipid extract and the methanol-solvent extract from Holothuria atra, Holothuria scabra and Bohadshia argus were found to show no antibacterial activity. 3. Phosphate-buffered saline (PBS) from H. atra and B. argus, however, inhibited the growth of all gram-positive and gram-negative bacteria. 4. Comparisons were also made between extracts from the outer layer of H. atra and its inner part, and it was found that the extract from the outer layer showed less bacterial growth inhibition property. 5. The bacterial growth inhibition property of the PBS extract from H. atra, however, is dependent on the extract's concentration. Bacterial growth inhibition was apparent after 48 hr incubation.

Screening for antibacterial agents in three species of sea cucumbers from coastal areas of Sabah.

In a biological system the product of free-radical induced-lipid peroxidation are conjugated dienes (CDs), lipid peroxides and malondialdehyde (MDA). Its control depends on antioxidant activities. Antioxidant defend the body system by controlling the damage caused by the free radicals. This paper describes lipid peroxidation process and antioxidant activities present in three species of holothuroid obtained from the coastal waters of Terengganu, Malaysia. Among the three species studied, the coelomic fluid of Bohadschia mamorata vitiensis contained the highest level of protein (7.24 + 0.04)g/L. The coelomic fluid of Stichopus badionotus Selenka contained the highest level of superoxide dismutase (SOD) (9.46 + 0.99)X 105 IU/g protein, MDA (16.46 + 1.28)nmol/g protein and total antioxidant activities (AOA) (58.81 + 5.70) %. In Stichopus variegatus Semper the coelomic fluid only demonstrated the highest level of CDs (94.19 + 11.34) RU/g protein compared with the other two species. This preliminary study indicated that some form of antioxidant activities are present in the coelomic fluid of holothuroids.

The potential of the coelomic fluid in sea cucumber as an antioxidant.

1. 30 mg kg-1 chlorpromazine (CPZ) depleted more than half of the tissue histamine from lungs, stomach, ileum and skin of the normal guinea-pigs. However, the drug increased the tissue histamine content in scorbutic animals. 2. In contrast, reserpine depleted histamine from the four tested tissues in both normal and scorbutic animals, except those in the lungs of the control animals. 3. Ascorbic acid only depleted histamine from the stomach and ileum. 4. A 24 hr period was the time limit for CPZ to deplete the histamine in all the four tested tissues. 5. Histamine partially or completely recovered in the tissues after the next 24 hr.

B.H. Ridzwan

Papers

Fatty acid compositions in local sea cucumber, Stichopus chloronotus, for wound healing.

Screening for antibacterial agents in three species of sea cucumbers from coastal areas of Sabah.

The potential of the coelomic fluid in sea cucumber as an antioxidant.

The depletion effects of chlorpromazine, reserpine and ascorbic acid on tissue histamine of guinea-pigs.

In vitro estimation of non-specific and specific amino acid decarboxylase activities in guinea-pigs treated with chlorpromazine.