**4. Conclusions**

In this review, we presented the chemical constituents of the mangrove-associated ecosystem and showcased the diversity of the chemical structures, biological activities, chemical syntheses, and (proposed) biosynthetic pathways.

Structurally diverse secondary metabolites play a crucial role in the discovery campaigns for new NP drug pharmacophores. The mangrove ecosystem is producing various

structurally novel compounds that could provide a potent compound library for the identification of lead compounds. Herein, we presented a comprehensive review of 134 mangrovederived NPs with new carbon skeletons, unique ring systems, or uncommon structural moieties. The majority of them were produced by mangrove-associated microorganisms, and more than 70% were isolated from endophyte fungus, indicating remarkable chemical diversity and interesting bioactivity of the microbial community. The structural novelty and diversity of these metabolites result from the enormous variety of mangrove ecosystems in combination with their potential biosynthetic capabilities. In addition, they display diverse and remarkable biological activities and are frequently reported as antimicrobial and cytotoxic compounds (Tables 1 and 2), which might attract researchers for further investigations toward chemical synthesis and biosynthesis. Mangrove ecosystems are a rewarding source for producing bioactive substances with novel carbon frameworks and discovering drug lead compounds, attracting pharmaceutical scientists for more in vivo and preclinical studies on these compounds.

**Table 1.** Structurally unusual secondary metabolites from mangrove flora.


a NR: not reported in references.

**Table 2.** Structurally unusual secondary metabolites from mangrove-associated microorganisms.


