**Conflict of interest**

*Plant Communities and Their Environment*

of marine alkaloids, further research and study successfully separated sufficient

Terpenes known as main algae metabolites, have chemical structure including five-carbon precursor. They are classified into, hemiterpenes, including five carbons (C5); monoterpenes, including ten carbons (C10); sesquiterpenes, including fifteen carbons (C15); diterpenes, including twenty carbons (C20); sesterterpenes, including twenty-five carbons (C25); triterpenes, including thirty carbons (C30) and polyterpenes, including above thirty carbons (>C30). It is known that some seaweeds contains terpenes. Chlorophyceae is one of them. It contains cyclic and linear sesqui-, di-, and triterpenes. The other one is Rhodophyceae and contains high structural diversity of halogenated secondary metabolites whose polyhalogenated monoterpenes show a variety of antibacterial properties (Perez et al., 2016; [68]).

In recent decades, seaweed was thought as an abundant and renewable natural resource. Especially, edible seaweeds are rich in polysaccharides, unsaturated fatty acids, protein composition, vitamins, and minerals, as well as natural bioactive compounds such as alkaloids. Their main component, polysaccharides may vary

amount of pure organic derivatives for biological testing [66].

*Indolines 8–24, including indolenine (13), isolated from F. foliacea (adapted from [66]).*

**202**

**2.3 Terpenes**

**Figure 11.**

**3. Conclusion**

The authors declare no conflict of interest.
