Phytochemical and Potential Properties of Seaweeds and Their Recent Applications: A Review

Abstract

Since ancient times, seaweeds have been employed as source of highly bioactive secondary metabolites that could act as key medicinal components. Furthermore, research into the biological activity of certain seaweed compounds has progressed significantly, with an emphasis on their composition and application for human and animal nutrition. Seaweeds have many uses: they are consumed as fodder, and have been used in medicines, cosmetics, energy, fertilizers, and industrial agar and alginate biosynthesis. The beneficial effects of seaweed are mostly due to the presence of minerals, vitamins, phenols, polysaccharides, and sterols, as well as several other bioactive compounds. These compounds seem to have antioxidant, anti-inflammatory, anti-cancer, antimicrobial, and anti-diabetic activities. Recent advances and limitations for seaweed bioactive as a nutraceutical in terms of bioavailability are explored in order to better comprehend their therapeutic development. To further understand the mechanism of action of seaweed chemicals, more research is needed as is an investigation into their potential usage in pharmaceutical companies and other applications, with the ultimate objective of developing sustainable and healthier products. The objective of this review is to collect information about the role of seaweeds on nutritional, pharmacological, industrial, and biochemical applications, as well as their impact on human health.

Keywords: antioxidant activity; functional foods; health benefits; seaweeds; secondary metabolites.

Figure 1

Three example species of brown (a) red (b) and green (c) seaweeds. Adapted from ref. [14] obtained from mdpi journals.

Figure 2

Main bioactive compounds from marine seaweeds.

Figure 3

Chemical structures of different types of polysaccharides in seaweeds.

Figure 4

Chemical structures of different types of pigments in seaweeds.

Figure 5

Several seaweeds synthesize phenolic substances. Adapted from ref [194] obtained from mdpi journals. (A)—Ascophyllum nodosum (P); (B)—Bifurcaria bifurcata (P); (C)—Fucus vesiculosus (P); (D)—Leathesia marina (P); (E)—Lobophora variegata (P); (F)—Macrocystis pyrifera (P); (G)—Asparagopsis armata (R); (H)—Chondrus crispus (R); (I)—Gracilaria sp. (R); (J)—Kappaphycus alvarezii (R); (K)—Neopyropia sp. (R); (L)—Palmaria palmata (R); (M)—Dasycladus vermicularis (Chl); (N)—Derbesia tenuissima (Chl); (O)—Ulva intestinalis (Chl); P—Phaeophyceae, R—Rhodophyta; Chl—Chlorophyta.

Figure 6

Chemical structures of different types of phenols in seaweeds.

Figure 7

Damage caused via reactive oxygen species (ROS). Adapted from ref. [233] obtained from mdpi journals.

Figure 8

Reactive oxygen species and neutralization by several biomolecules.

Figure 9

Demonstrate the ability of algal polysaccharide (SP)-based customized signals produced from sea algae to cause tumor cell death (apoptosis). Adapted from ref. [233] obtained from mdpi journals.

Figure 10

Illustration demonstrating beneficial effects of seaweed extracts on the entire soil-plant system. Such impacts include increased fruit quality and phytohormone content in plants, increased soil enzymatic activity, improved roots system, and overall physiological properties of plants. Adapted from ref. [315] obtained from mdpi journals.

Figure 11

A summary for the bioactive compounds that have different biological activities and used in different applications. Adapted from ref. [384] obtained from mdpi journals.