Pullenvalenes E-H: Triterpenyl-Aminoglycosides from an Australian Soil-Derived Fungus, sp.

Chemical profiling of soil-derived microbes collected under the auspices of the Australian citizen science initiative Soils for Science detected two fungi, sp. S4S-07771A07 and sp. S4S-14879B01, capable of producing pullenvalenes, a rare class of triterpene glycoside. Cultivation profiling followed by scaled up cultivation and fractionation of the former yielded the known pullenvalenes A-D (-) and the new analogues E-H (-), with structures secured by detailed spectroscopic analysis and biogenetic considerations. This study reveals that the pullenvalenes - are produced by several genera of fungi (, and ) recovered from different geographic locations and substrates. We also draw attention to structural and biosynthetic similarities with the known Red Sea sponge metabolites neviotines A-D (-) and abudinols A-B (-), prompting speculation that the latter may be products of sponge-associated fungi.