Novel Bioactive Compounds from Marine Algae: Promising Candidates for Natural Product-based Drug Development

Izabela Reinhardt^*
*Correspondence: Izabela Reinhardt, Department of Biological Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK, Email:

Introduction

Marine algae, a rich and diverse source of bioactive compounds, have long been explored for their potential applications in pharmaceutical and nutraceutical industries. Over the past few decades, marine algae have gained significant attention as a source of novel natural products with a wide range of biological activities, including anticancer, antimicrobial, anti-inflammatory, and antiviral properties. This review aims to provide a comprehensive overview of the novel bioactive compounds derived from marine algae and their therapeutic potential in drug development. We explore the chemical diversity of these compounds, including polysaccharides, terpenoids, peptides, fatty acids, and phenolic compounds, and highlight their pharmacological activities. Additionally, we discuss recent advancements in marine algae-derived drug discovery, the challenges involved in translating these compounds to clinical applications, and the future prospects for developing marine algal-based therapies. By identifying key bioactive molecules and mechanisms of action, this review underscores the significance of marine algae as a promising resource for novel drug development.

Marine ecosystems are a treasure trove of biodiversity, with marine algae representing one of the most prolific groups of organisms in terms of chemical diversity. Marine algae, including both macroalgae (seaweeds) and microalgae, produce a wide variety of secondary metabolites that play crucial roles in ecological interactions and survival. These compounds have evolved to serve various functions, such as defense against herbivores, UV radiation, and microbial pathogens, many of which have potential therapeutic applications for humans.

The pharmaceutical industry has recognized the immense potential of marine algae in drug discovery, particularly for the development of novel natural products. Marine algae-derived compounds have been shown to possess a broad spectrum of biological activities, making them ideal candidates for drug development in various therapeutic areas, including cancer, cardiovascular diseases, diabetes, and infections. Some of the most promising compounds are polysaccharides, terpenoids, fatty acids, peptides, and phenolic compounds, all of which exhibit diverse pharmacological properties.

This review summarizes the recent findings on bioactive compounds from marine algae, highlighting their mechanisms of action, therapeutic potential, and challenges faced in their clinical development. We also provide insights into the future directions of marine algae-based drug development. A systematic literature review was conducted to identify relevant studies on bioactive compounds from marine algae. Databases such as PubMed, Scopus, Web of Science, and Google Scholar were searched for articles published from 2000 to 2024. Key search terms included "marine algae," "bioactive compounds," "natural products," "drug development," "anticancer," "antimicrobial," and "pharmacological activity."

Description

Data extraction involved identifying the type of algae, bioactive compounds, biological activities, mechanisms of action, and potential therapeutic applications. The data were synthesized into categories based on the chemical structure of the compounds (e.g., polysaccharides, terpenoids, peptides) and their associated pharmacological properties. Polysaccharides are among the most well-studied bioactive compounds derived from marine algae. These include fucoidans, agar, carrageenans, and alginates, which are found in brown, red, and green algae, respectively. Marine algal polysaccharides have demonstrated a wide array of biological activities, including immunomodulatory, antiviral, anticoagulant, and anticancer effects.

Fucoidan, a sulfated polysaccharide primarily isolated from brown algae (Fucus vesiculosus, Undaria pinnatifida, and Laminaria spp.), has shown promising therapeutic potential. Fucoidan exhibits potent anticancer activity by inducing apoptosis, inhibiting metastasis, and enhancing immune responses. It has also been shown to reduce tumor growth and enhance the effects of chemotherapy agents. Additionally, fucoidan possesses antiviral properties, particularly against hepatitis B and C viruses, and has demonstrated anticoagulant activity [1-3].

Carrageenans, a family of sulfated polysaccharides found in red algae (Chondrus crispus, Eucheuma cottonii), are known for their immunomodulatory, anti-inflammatory, and antioxidant activities. Carrageenans have been investigated for their potential as adjuvants in cancer therapy, as they can enhance the effectiveness of chemotherapeutic agents and prevent cancer cell proliferation by modulating immune responses. Terpenoids, also known as isoprenoids, are another important class of bioactive compounds found in marine algae, particularly in red and brown algae. These compounds exhibit a wide range of pharmacological activities, including anticancer, antimicrobial, anti-inflammatory, and antioxidant effects.

Halogenated terpenoids, such as bromophenols and dibromomethylnorcarotenoids, have been isolated from various marine algae, including Corallina officinalis and Dictyota spp. These compounds exhibit strong anticancer and antimicrobial properties. For example, dibromomethylnorcarotenoids have demonstrated cytotoxic effects against various human cancer cell lines, including those from breast, lung, and colon cancers. Phlorotannins, a group of polyphenolic compounds found in brown algae (Ecklonia cava, Ascophyllum nodosum), are known for their antioxidant, anti-inflammatory, and anticancer activities. These compounds act through several mechanisms, including the inhibition of cancer cell proliferation, induction of apoptosis, and modulation of oxidative stress. Phlorotannins have also shown potential in preventing cardiovascular diseases by reducing lipid peroxidation and inflammation..

Marine algae are a rich source of bioactive peptides with various therapeutic potentials. These peptides have been isolated from both microalgae (e.g., Chlorella spp., Spirulina spp.) and macroalgae (e.g., Laminaria japonica). Several marine algal peptides have shown anticancer activity by inducing apoptosis and inhibiting metastasis. For example, a peptide isolated from Spirulina (Spirulina platensis) has demonstrated cytotoxic effects against human leukemia cells. Similarly, peptides from Laminaria japonica have exhibited selective cytotoxicity against colorectal cancer cells. Marine algal peptides also exhibit potent antimicrobial activity. For example, peptides isolated from Chlorella vulgaris have been shown to inhibit the growth of various pathogenic bacteria, including Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. These peptides can be considered as potential candidates for the development of novel antimicrobial agents, especially in the face of rising antibiotic resistance.

Marine algae are an abundant source of polyunsaturated fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid, which are known for their anti-inflammatory, anticancer, and cardiovascular protective effects. Both EPA and DHA have been investigated for their role in cancer prevention and treatment. These fatty acids exhibit anticancer properties by modulating signal transduction pathways, including the inhibition of COX- 2, NF-κB, and VEGF, thereby reducing tumor growth and angiogenesis. Furthermore, EPA and DHA have been shown to potentiate the effects of chemotherapy and radiation therapy in several cancer models. Phenolic compounds derived from marine algae, including phlorotannins, flavonoids, and stilbenes, exhibit various biological activities, including antioxidant, antiinflammatory, and anticancer effects [4,5].

As mentioned earlier, phlorotannins derived from brown algae (Ecklonia cava, Sargassum spp.) have shown significant antioxidant and anticancer activities. These compounds scavenge free radicals, reduce oxidative stress, and inhibit the proliferation of cancer cells, particularly in breast, colon, and liver cancer models.

Many marine algae-derived compounds, such as fucoidan, terpenoids, and peptides, promote apoptosis by activating caspases, modulating Bcl- 2 family proteins, and disrupting mitochondrial integrity. Compounds like EPA and DHA inhibit angiogenesis by downregulating VEGF and other proangiogenic factors, limiting tumor growth. Marine algae-derived peptides and polyphenolic compounds disrupt microbial cell membranes, inhibit bacterial growth, and prevent the formation of biofilms. Several compounds from marine algae, such as phlorotannins, inhibit inflammatory pathways by suppressing NF-κB, COX-2, and TNF-α, which are involved in the pathogenesis of cancer and other chronic diseases. extraction and purification of bioactive compounds from marine algae can be complex and costly, which limits the scalability of production.

Many marine algae-derived compounds have low bioavailability due to poor absorption, metabolism, and distribution in the body. While many algal compounds are considered safe, long-term toxicity studies and clinical trials are needed to ensure their safety in humans. The regulatory approval process for natural products is often more challenging compared to synthetic drugs, requiring extensive preclinical and clinical data. Future research should focus on optimizing extraction methods, enhancing the bioavailability of active compounds, and conducting rigorous clinical trials to evaluate the safety and efficacy of marine algae-based therapies.

Conclusion

Marine algae are a promising and largely untapped source of novel bioactive compounds with significant therapeutic potential. From anticancer agents to antimicrobial peptides, marine algae-derived compounds exhibit a diverse range of pharmacological activities that could lead to the development of new natural product-based drugs. However, challenges such as extraction techniques, bioavailability, and regulatory hurdles must be addressed to fully realize the potential of marine algae in drug development. Continued research and technological advancements in marine biotechnology will likely drive the future of marine algae-based therapeutics.

Acknowledgment

None.

Conflict of Interest

None.

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