Simple or Cyclized Oroidin-like Dimers

The fungicidal activity of sceptrin at 10 ppm was found to be 65 % inhibition of Phytophthora infestans (potato late blight) [103]. In addition to its antimicrobial, antiviral [104], antimuscarinic [22], and antihistaminic [30] properties, sceptrin was shown to be the first and most potent nonpeptide somatostatin inhibitor in the submicromolar range [105]. 

Despite its potent biological activity, sceptrin remained a prominent unanswered synthetic challenge until 2004. Although upon cursory inspection it appears to be a photodimer of hymenidin, synthetic strategies involving the dimerization of 2 have been futile. The first short total synthesis of sceptrin in its racemic form was 

Sceptrin has also been found in several different sponges, co-occurring vith related compounds. Oxysceptrin (67), previously found by Rinehart et al. in a sample of Agelas conifera [109], vas re-isolated by Kobayashi et al. together vith sceptrin from the Okinawan sponge Agelas cf nemoechinata [110]. Its activity as an actimyosin-ATPase activator has been reported [110]. 

Numerous antiviral and antibacterial sceptrin/oxysceptrin derivatives (68-72), along with the diacetate salts of sceptrin and oxysceptrin, were isolated from Agelas conifera [104,111,112]. 

Dibromosceptrin (69), tested together with other brominated pyrrole alkaloids for interaction with cellular calcium homeostatis, was shown to reduce voltage-dependent calcium elevation in PC12 cells [113]. 

---