Goondomycins\nA–H: Carbocyclic <i>ansa</i>-Polyketides from an\nAustralian Pasture <i>Streptomyces</i> with Selective Activity\nagainst <i>Dirofilaria immitis</i>

A bioassay-guided\nchemical investigation of an Australian\npasture-soil-derived <i>Streptomyces</i> sp. yielded the\nrare carbocyclic <i>ansa</i>-polyketide kendomycin (<b>1</b>) along with a series of new\nanalogues, goondomycins A–H (<b>2</b>–<b>9</b>), featuring unprecedented carbo/heterocyclic scaffolds and chromophores,\nwith structures assigned by detailed spectroscopic analysis, chemical\nand biochemical transformations, and biosynthetic considerations.\nGoondomycins B (<b>2</b>) and F (<b>7</b>) are noteworthy\nin being potent motility inhibitors of heartworm <i>Dirofilaria\nimmitis</i> microfilaria (EC<sub>50</sub> 0.3 and 0.5 μM)\nand L4 larvae (EC<sub>50</sub> 1.4 and 1.8 μM), while exhibiting\nno significant antibacterial and antifungal activity or cytotoxicity\nto mammalian cells.