*Article* **New Angucycline Glycosides from a Marine-Derived Bacterium** *Streptomyces ardesiacus*

**Cao Van Anh 1,2, Joo-Hee Kwon 3, Jong Soon Kang 3, Hwa-Sun Lee 1, Chang-Su Heo 1,2 and Hee Jae Shin 1,2,\***


**Abstract:** Chemical investigation of the ethyl acetate extract from the culture broth of the marinederived actinobacterium *Streptomyces ardesiacus* 156VN-095 led to the isolation of three hitherto undescribed angucycline glycosides, including urdamycins W and X (**1** and **2**) and grincamycin U (**9**), as well as their seven known congeners. The structures of the new compounds were elucidated by means of spectroscopic methods (HRESIMS, 1D and 2 D NMR) and comparison of their experimental data with literature values. Compounds **1**–**3** and **9** were evaluated for their anti-Gram-positive bacterial effect and cytotoxicity against six cancer cell lines. Compound **1** displayed significant cytotoxicity against all the tested cell lines with GI50 values of 0.019–0.104 μM. Collectively, these findings highlight the potential of angucycline glycosides as leading structures for the development of new anti-cancer drugs.

**Keywords:** *Streptomyces ardesiacus*; urdamycin; grincamycin; anti-bacterial; cytotoxicity
