**7. Meroterpenes**

**6. Triterpenes**

8 Terpenes and Terpenoids

**Figure 6.** Structure of triterpenes.

A major class of secondary metabolites are known as triterpenes and it usually contains 30 carbon atoms consisting of 6 isoprene units (**Figure 6**). It is derived from the squalene biosynthetic pathway. Triterpenes have many methyl groups and it can be oxidized into alcohols, aldehydes, and carboxylic acids, which make it complex and differentiate it biologically. Triterpenes have many active sites for the glycosylation which converts it into another big class of compounds, namely, saponins (triterpene glycoside). Herein, we are

discussing some recently published bioactive triterpenes (**Table 5**).

Meroterpenes are the secondary metabolites with partial terpenoid skeleton. Meroterpenoids were partially derived from mevalonic acid pathways and widely derived from animals, plants,

**Figure 7.** Structures of meroterpenes.


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0.1021/acs.jnatprod.7b00698

**Table 6.** Source and biological activities of some meroterpenes.

bacteria, and fungi [21] (**Figure 7**). Meroterpene biosynthesis expands the diversity available to isoprenoid pathways alone and allows for the assembly of natural products with highly unique structural attributes. Organisms belonging to the fungal kingdom have become proficient at exploiting this broad chemical synthesis platform for complex metabolite production. Herein, we are discussing some of the recently published bioactive meroterpenes (**Table 6**).
