*2.3. Prioritization—Metabolic Fingerprinting*

Results from metabolic fingerprinting and bioactivity screening were combined to allow prioritization of samples and are summarized in Figure 3. The detailed grouping results with pairwise similarities are presented in Table S1. While a total of 45 distinct metabolic groups was generated, extracts sharing the same activity pattern (KOL\_8, KOL\_16, KOL\_18, and ULU\_13) were assigned to the same group (Figure 3), strongly suggesting a similar metabolite composition of the extracts (see also Figure 4). Similarly, extracts ULU\_11 and ULU\_17 formed one group, while extracts PEHE\_5, PANIKI\_4, and ULU\_16 appeared to consist of unique metabolite mixtures. From each metabolic group containing bioactive extracts, one representative was selected for microfractionation. Samples selected for microfractionation are marked.

**Figure 3.** Cosine similarity heatmap of all 76 extracts. Blue color indicates a high degree of similarity among compared extracts (see color key histogram). Flags in sidebar mark selected samples for microfractionation (black) and screening results (red = active, orange = weak activity, white = inactive) of the respective extract against the indicator strains (CALB = *C. albicans*, STRI = *S. tritici*, SAUR = *S. aureus*, PAER = *P. aeruginosa*, ECOL = *E. coli*).

**Figure 4.** Base peak chromatogram (BPC) of the extracts KOL\_08, KOL\_16, KOL\_18, and ULU\_13 obtained from different *Agelas nakamurai* organisms. Most intense peaks within the similar BPCs correspond to the agelasines groups (box, top right) and agelasidine A (box, top left).
