Chemical diversity and therapeutic potentialities of seaweeds and marine sponges collected from the Red Sea: An update

The marine environment is a vast and diverse ecosystem that is a valuable source of biologically active ingredients for the drug industry. For decades, natural products from marine organisms have been a major supplier of curative agents. Over 30,000 metabolites have been recorded from different marine organisms and associated microorganisms. Marine-derived compounds have diverse chemical structures, biological and pharmacological applications, making them a promising platform for drug discovery from natural sources. This review highlights a comprehensive survey of the phytochemical and biological aspects of selected seaweed and marine sponges found in the Red Sea. These organisms, such as seagrass ( Thalassia hemprichii ) and marine sponges ( Siphonochalina siphonella , Latrunculia magnifica , and Crella (Grayella) cyathophora ), have been found to contain numerous chemical ingredients with therapeutic properties. Phenolic compounds in T. hemprichii have antioxidant and anticancer properties while marine sponges contain structurally diverse amides, alkaloids, terpenes, and steroids with cytotoxic, antiviral, and antimicrobial activities. The habitats of these organisms affect both the chemical components and their biological properties. These findings are encouraging and may be used in the development of new pharmaceuticals.


INTRODUCTION
Natural products (NPs) have a long history in pharmacotherapy, especially in the management of cancer and infectious disturbances (Carroll et al., 2023;Chen et al., 2023).Naturally occurring bioactive chemicals have become an essential source of drugs since they have been used to treat a variety of diseases (Abdel-Aziz et al., 2018;Elkhouly et al., 2021aElkhouly et al., , 2021b;;Mohammed et al., 2019;Yang et al., 2023aYang et al., , 2023b;;Yeung et al., 2018).Scientists are dealing with various illnesses in our community owing to reestablished circumference and life manner.Several researchers are working on the different emerging diseases to understand and cure them by using various chemical and natural preparations; however, still, numerous topics are untouched due to inferior knowledge and technical tools (Aditi et al., 2017;Bode et al., 2002;El-Wakil et al., 2022).NPs have been utilized for the remediation of several ailments and diseases since ancient times (Dias et al., 2012;El-Demerdash et al., 2012;Ghareeb et al., 2023;Holland and Carroll, 2023;Mohammed et al., 2022;Okasha et al., 2022;Sayed et al., 2022).The earliest records of NPs used were from 8000 BC.Most of the evidences for the earliest use of NPs for medication comes from archaeologists who have explored some ancient sites such as caves (Dias et al., 2012).The Egyptian Ebers Papyrus (2900 BC) documents up to 700 plant-based drugs to create prescriptions, ointments, potions, inhalers, and pills to cure certain conditions.Opium, cannabis, and linseed oil were used (Cragg and Newman, 2005).The Chinese materia medica (1100 BC) (Wu Shi Er Bing Fang, comprises 52 prescriptions), Shennong Herbal (~100 BC, 365 drugs), and the Tang Herbal (659 AD, 850 drugs) are documented archives of the utilization of NPs (Cragg and Newman, 2005).The Greek physician Hippocrates, , the father of modern medicine and possibly the most recognized name in medicine, was born in Greece (Porter, 1998).In the 8th century, the Arabs were the first to privately own pharmacies.The poet, philosopher, pharmacist, and physician "Avicenna" participated much in the disciplines of pharmacy and medicine within works like the Canon Medicine (Cragg and Newman, 2005).Taken together, the current review aims to explore the chemical and biological aspects of some marine algae and marine sponges collected in the Red Sea, in order to build a comprehensive and intensive vision of what has been discovered in such an environment, which is considered a strategic treasure for obtaining medicines from natural sources.

MATERIALS AND METHODS
In our current study, the subsequent databases and search engines have been used to get the peer-reviewed articles: the Marin-Lit database "The Royal Society of Chemistry," Google Scholar, MDPI, Science Direct, SciFinder, and PubChem.The search keywords are "Natural products (NPs), Marine natural products (MNPs), Approved marine drugs, chemical and biological profiles of Thalassia hemprichii, Siphonochalina siphonella, Latrunculia magnifica, and Crella (Grayella) cyathophora."The search covers the period 1980-2023.The selection of topics relied on articles that give a general overview of marine organisms, including chemical and biological profiles, and then the search was focused in depth on the organisms under study from the chemical and biological aspects.Also, ChemOffice was also utilized to draw the chemical skeletons.Additionally, Excel was used to draw graphs.

CHEMISTRY AND BIOLOGICAL IMPORTANCE OF SELECTED SEAGRASS AND MARINE SPONGES COLLECTED FROM THE RED SEA
In this manuscript, we present up-to-date insights about chemical and biological diversifications of selected marine organisms, with a focus on those collected from the Red Sea coastal areas.For the handling of this documentation, all isolated MNPs are tabulated where they have been recovered along with their recorded biological potentialities whenever possible.
Chemical investigations of the ethanol extract of seagrass T. hemprichii obtained from South China led to the isolation

Marine sponge C. (Grayella) cyathophora: secondary metabolites and their bioactivities
Reviewing the literature indicates that there are inadequate previous studies related to the chemical characterization of various extracts of C. (Grayella) cyathophora.

Biological and pharmacological activities of marine sponge C. (Grayella) cyathophora extracts
The aqueous ethanol extract of marine sponge C. (Grayella) cyathophora collected from the Gulf of Aqaba, Red Sea, Egypt, showed cytotoxic activity to Vero cells with hepatitis A virus with a MIC value of 2.929 μg/ml.The extract showed antibacterial activity against P. aeruginosa.Also, it showed antioxidant activity with IC 50 value of 748 μg/ml.Moreover, the anti-inflammatory activity was 89.91% (El-Damhougy et al., 2017).
To sum up, the biological activities of some extracts and the main chemical classes as well as the biological activities of some reported compounds are summarized in Figure 10.

CONCLUSION
One of the distinguishing characteristics of marinederived compounds is the diversity of their chemical structural, biological and pharmacological applications, which makes it a promising dais for drug discovery from natural sources.This review highlights an up-to-date comprehensive survey regarding the phytochemical and biological aspects of seaweed and marine sponges.Additionally, this review delivers a sign that numerous chemical ingredients have been isolated or identified from seagrass (T.hemprichii) and marine sponges (S. siphonella, L. magnifica, and C. (Grayella) cyathophora).The dominant compounds in T. hemprichii are phenolic compounds, while the dominant compounds in marine sponges are amides, alkaloids, terpenes, and steroids.Some of the reported compounds showed a broad spectrum of biological activities including antiviral, antibacterial, cytotoxicity, anti-quorum sensing (anti-QS), antibiofilm, antiproliferative, anti-inflammatory, and antitrypanosomal activities.Moreover, it was noted that both types of chemical components and their biological properties are affected by the habitats of these organisms.These marine organisms are considered the most attractive biological targets and deserve more biological exploration due to the biological activities demonstrated by their chemical components as well as their various extracts.Moreover, this review sheds light on the enormous correlation between the chemical entities and the biological activities of marine-derived fungi.To sum up, these findings are likely to be used in the development of the pharmaceutical industry.

Figure 8 .
Figure 8.Chemical structures of polyacetylenic alcohols compounds (58-62) isolated from the chloroform-soluble fraction of the marine sponge S. siphonella, obtained from southwest of Magawish Island, Hurghada, Egypt; brominated oxindole alkaloids compounds (63, 64) isolated from the marine sponge C. siphonella collected from Hurghada, Red Sea Coast, Egypt; and a sterol compound (65) separated from the marine sponge C. siphonella obtained from the Red Sea, Egypt.

Figure 9 .
Figure 9.Chemical structures of macrolide compounds (66-68) separated from the Red Sea sponge L. magnifica; compounds (69, 70) isolated from petroleum ether extract of L. magnifica collected from Gulf of Eilat; and compounds (71-74) separated from the Red Sea sponge L. magnifica.

Figure 10 .
Figure 10.Reported biological activities for compounds isolated seaweed and marine sponge collected from Red Sea marine organisms.