*3.1.2. Labdanes*

The labdane-related diterpenoids are a special group, consisting of over 7000 members, which are distinguished by their unique biosynthesis. Gibberellin phytohormones as well as antibiotics such as some of phytoalexins and phytoanticipins fall into this family [34]. Labdanolic acids have been identified as biomarkers for the botanical origin of French ambers [35], while copalic acid and its relatives have been associated with the biological activity of the resins from *Copaifera* species. The lanceolatins are a group of **labdanes** and **abietanes** which were obtained [40] from *Cephalotaxus lanceolata* (Cephalotaxaceae). Some of the abietanes were described in this chapter as well (**Figure 4**).

*3.2.1.1.1. Abietic acid*

**Figure 5.** Classification of tricyclic abietane diterpenes.

*3.2.1.1.2. Dehydroabietic acid*

Abietic acid was extensively studied in various organisms for its biological activities. Current data also suggest that abietic acid is an important compound for synthesis of novel metabolites. They contribute to the body of knowledge related to compound 1 and deepen the under-

Diterpenes from Different Fungal Sources and Their 13C-NMR Data

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Dehydroabietic acid displays not only antiulcer and antimicrobial properties but also antitumor and anti-inflammatory effects (compound 2). Antimicrobial effects of DHA have been

Biological activity: It also showed activity against other Gram-positive organisms such as *Salmonella* sp., *Bacillus subtilis*, and *E. coli* [44]. This latter study also described the inhibition of nitric oxide (NO) production by DHA, which was reported by other researchers as well [49]. Kawada et al. [45] have reported in relation with the inhibition of pro-inflammatory cytokines

studied, specifically against methicillin-resistant strains of *Staphylococcus aureus* [43].

standing of the potential and properties of 1 and its derivatives (**Figure 7**).

that DHA is useful for treating obesity-related diseases.

**Figure 6.** Abietane skeleton with some standard compounds [41].
