Polycyclic Hybrid Isoprenoids from a Reed Rhizosphere Soil Derived Streptomyces sp CHQ-64

Two new hybrid isoprenoids, named indotertine B (2) and drimentine H (3), along with the known analogue drimentine C (4), were isolated from the reed rhizosphere soil derived actinomycete Streptomyces sp. CHQ-64. The structures of these compounds, including absolute configurations, were elucidated by extensive NMR, MS, and CD analyses. Indotertine B (2) exists as a pair of rotamers about the N-C(O) bond with a 2:1 ratio and displays activities against HCT-8 and A549 tumor cell lines with IC50 values of 6.96 and 4.88 mu M, respectively.