 Likewise, (S) 2-amino-4-oxo-5-hydroxypentanoic acid (RI-331), another amino acid analog, has also been shown to inhibit HSD.Both of these compounds are effective against "Cryptococcus neoformans" and "Cladosporium fulvum", among others.In addition to amino acid analogs, several phenolic compounds have been shown to inhibit HSD activity.