17-O-Ethylnotoamide M (16), 17-hydroxynotoamide D (23) and 10-O-ethylnotoamide R (33) (Figure 4) were evaluated for their effects on the viability of human non-malignant and prostate cancer cells as well as on the colony formation of human prostate cancer cells 22Rv1, which are known to be resistant to hormone therapy including the novel second generation drugs abiraterone and enzalutamide due to the presence of androgen receptor splice variant AR-V7. Here, AR is linked to prostate cancer.