Abstract
The
Condylactis
-genus anemones were examined for their proteinaceous poisons over 50 years ago. On the other hand, the current research focuses on isolating and describing the non-proteinaceous secondary metabolites from the invasive
Condylactis
anemones, which help take advantage of their population outbreak as a new source of chemical candidates and potential drug leads. From an organic extract of
Condylactis
sp., a 1,2,4-thiadiazole-based alkaloid, identified as 3,5-bis(3-pyridinyl)-1,2,4-thiadiazole (
1
), was found to be a new natural alkaloid despite being previously synthesized. The full assignment of NMR data of compound
1
, based on the analysis of 2D NMR correlations, is reported herein for the first time. The proposed biosynthetic precursor thionicotinamide (
2
) was also isolated for the first time from nature along with nicotinamide (
3
), uridine (
5
), hypoxanthine (
6
), and four 5,8-epidioxysteroids (
7
–
10
). A major secondary metabolite (−)-betonicine (
4
) was isolated from
Condylactis
sp. and found for the first time in marine invertebrates. The four 5,8-epidioxysteroids, among other metabolites, exhibited cytotoxicity (IC
50
3.5–9.0 μg/mL) toward five cancer cell lines.