*2.4. Macrolide*

There were no reported macrolides from the co-cultures of marine fungi–fungi and fungi–bacteria. Only one isolate was identified from a co-culture of marine bacteria–bacteria.

Macrolides Derived from the Co-Cultures of Different Marine Bacteria

A known compound, nonactin (**100**) (Figure 17) was isolated from the co-culture of two marine bacteria, *Saccharomonospora* sp. UR22 and *Dietzia* sp. UR66 [51]. It possessed a macrotetrolide structure integrated from nonactic acid, and exhibited antitumor and antibacterial activity, especially its inhibitory effects on the P170 glycoprotein-mediated efflux of chemotherapeutic agents in multiple-drug-resistant cancer cells [62–65].

**Figure 17.** Chemical structures of **100**.
