A REVIEW OF MARINE NATURAL PRODUCTS AS POTENTIAL SOURCE OF ANTIOXIDANTS

Article Highlights
- Marine Natural Products have been the most favorable source of bioactive compounds for drug discovery research.
- Many biologically active chemicals with antioxidant properties can be found in the marine environment.
- A systematic review on potential source of antioxidants linked to marine natural products was carried out.
- Algae, fungi, sponges, mollusks, and sea cucumbers were found to be abundant sources of antioxidants.
- Integrate these discoveries into practical applications for enhancing human health and well-being.

Abstract
Several diseases have been linked to oxidative stress, resulting from an imbalance between the creation of the body’s antioxidant defense mechanisms and reactive oxygen species (ROS). Due to their distinct metabolic makeup and wide range of biological adaptations, marine organisms have attracted interest as possible sources of new antioxidants. This systematic review aims to evaluate the antioxidant potential of marine natural products. To find relevant research published between 2002 and 2022, a thorough search strategy based on the PRISMA standards was used across databases, including PubMed, Google Scholar, Mendeley, and Science Direct. A total of 18 studies were extracted and included in the review. The results consistently showed that marine natural compounds had vigorous antioxidant activity. Algae, fungi, sponges, mollusks, and sea cucumbers were shown to be abundant sources of antioxidants in marine environments. Flavonoids, alkaloids, phenols, tannins, steroids, saponins, glycosides, terpenoids, and carotenoids are only a few types of marine natural products that have been discovered to possess strong antioxidant properties. This systematic review provides compelling evidence for the antioxidant potential of marine natural products. The research validates their potential as sources of novel antioxidants with various bioactive properties. Unlocking the full potential of marine natural products and integrating these discoveries into practical applications for enhancing human health and well-being calls for further research.

INTRODUCTION

It has been established that the ocean, a complex ecosystem, is an excellent chemical and biological diversity source. Compared to non-marine microorganisms and terrestrial plants, marine organisms have been regarded as the most recent source of bioactive natural compounds, including 75% of all living organisms from 36 phyla(Balakrishnan et al., 2014). In recent years, marine natural products (MNPs) are the most promising source of bioactive compounds for drug discovery research(Nie et al., 2020). Bacteria, algae, sponges, and other marine organisms make many subgroups of substances.

These mentioned organisms are extremely promising sources of fascinating compounds that might be applied to food, cosmetics, pharmaceuticals, and other compounds essential to industry.

Despite the enormous potential of MNPs, the marine ecosystem still represents an extensive undeveloped reservoir of biologically active chemicals, which has considerable potential to contribute food components towards producing new functional foods(Mishra et al., 2023). In the world’s seas, between 700,000 and one million different species can be found; however, only a small portion of all MNPs is being examined for their potential bioactivities ((Mohamed et al., 2012)&(, 2021)). Due to the growing need by the food and pharmaceutical industries to produce natural bioactive anti-carcinogenic and anti-aging substances which provide significant health benefits, antioxidant activity has become intensively discussed and the focus of significant research(Balakrishnan et al., 2014). Seaweed and sponges are among the marine organisms with the highest levels of natural antioxidants(Muthiyan et al., 2018). Bioactive substances produced by the said organisms and the bacteria that live on them have been proven to be crucial for illness prevention and health promotion. The complex blend of phytochemicals exhibiting antibacterial, antioxidant, anticancer, and antiviral action is responsible for these positive effects. Sulfated polysaccharides, Phenolic compounds, sand organic acids are responsible for these activities(Balakrishnan et al., 2014).

Thus, to increase the availability and chemical variety of functional marine constituents, more research is needed to completely comprehend the biological activities of MNPs and their potential health advantages(Mohamed et al., 2012). The use of MNPs as a potential source of bioactivity has been discussed in a few recent review publications(Fonseca et al., 2023). However, only a few systematic literature reviews have focused on its potential as a source of antioxidants(El-Shafei et al., 2021). Therefore, this review fills a gap in the existing literature by systematically reviewing the MNPs as a potential source of antioxidants.

METHODS

Study design and eligibility criteria

A review of literature conducted using a systematic search was employed using PRISMA guidelines. The following were used as inclusion criteria: (i) the study had to be focused only on primary research, such as experimental studies that looked into marine natural products as a source of antioxidants; (ii) it had to have used marine natural products, such as coral, seaweed, marine sponges, and other marine invertebrates, to look into anti-oxidant activity in humans; and (iii) the main outcome of interest was the antioxidant activity of marine natural products as measured by a recognized assay, e.g., ABTS, DPPH, FRAP, ORAC, etc., (iv) it had to be focused solely on antioxidant assays employing ethanolic and/or methanolic extracts, (v) the study had to be written in English, (vi) it had to be published between 2002 and 2022, and (v) had to be open-access, and peer-reviewed articles published in scientific journals. The study’s inclusion criteria were all met by a total of 18 papers.

Search Strategy

The search engine Science Direct, Google Scholar, PubMed, and Mendeley, were used to obtain the most relevant articles by using the words “marine natural products,” “marine natural resources,” and/or “marine products” combined with “antioxidant,” “antioxidants,” and “antioxidant activity. Only English, open-access peer-reviewed articles with full text were considered, preferably published between 2002 and 2022.

Data Extraction

The search engine Science Direct, Google Scholar, PubMed, and Mendeley, were used to obtain the most relevant articles by using the words “marine natural products,” “marine natural resources,” and/or “marine products” combined with “antioxidant,” “antioxidants,” and “antioxidant activity. Only English, open-access peer-reviewed articles with full text were considered, preferably published between 2002 and 2022.

Study Selection

After removing duplicates from a total of 1244 independently downloaded papers, 1093 published articles remained. 37 articles’ full-text versions were retrieved after their titles and abstracts were screened for further assessment. There are 19 articles with methods that still need to meet the inclusion criteria. In the end, only 18 qualified articles were used in this review, as illustrated inFigure 1.

RESULTS AND DISCUSSION

Studies of MNPs as Antioxidant according to Study Features

The analysis’s results indicate the level of distribution of MNP studies as a potential source of antioxidants in terms of (a) publication year, (b) marine sources, and (c) marine species.Figure 2below provides information on the frequency distribution of the studies based on the classified feature based on publication year.

Results revealed that out of the 18 qualified studies, only a few published studies focused mainly on the MNPs as a source of antioxidants (2002-2012, 0; 2013, 2; 2014, 2; 2015, 3; 2016, 3; 2017,0; 2018,1; 2019, 1; 2020, 2; 2021, 3; 2022, 1). These indicate that the chemistry of marine sources, in general, has yet to be fully embraced by the field of MNPs, at the expense of its potential as antioxidants based on the inclusion criteria developed for the purpose.

.....