Thailandins A and B, New Polyene Macrolactone Compounds Isolated from Actinokineospora bangkokensis Strain 44EHW^T, Possessing Antifungal Activity against Anthracnose Fungi and Pathogenic Yeasts

Abstract

Two new polyene macrolactone antibiotics, thailandins A, 1, and B, 2, were isolated from the fermentation broth of rhizosphere soil-associated Actinokineospora bangkokensis strain 44EHW(T). The new compounds from this strain were purified using semipreparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds demonstrated broad spectrum antifungal activity against fungi causing anthracnose disease (Colletotrichum gloeosporioides DoA d0762, Colletotrichum gloeosporiodes DoA c1060, and Colletotrichum capsici DoA c1511) as well as pathogenic yeasts (Candida albicans MT 2013/1, Candida parasilopsis DKMU 434, and Cryptococcus neoformans MT 2013/2) with minimum inhibitory concentrations ranging between 16 and 32 μg/mL. This is the first report of polyene antibiotics produced by Actinokineospora species as bioactive compounds against anthracnose fungi and pathogenic yeast strains.

The Draft Genome Sequence of Actinokineospora bangkokensis 44EHWT Reveals the Biosynthetic Pathway of the Antifungal Thailandin Compounds with Unusual Butylmalonyl-CoA Extender Units

“…Actinokineospora bangkokensis 44EHW T produces the polyene compounds thailandin A and thailandin B [ 8 ]. Thailandin B is probably the precursor of the A-form, because thailandin A is further rhamnosylated.…”

“…Thailandin B is probably the precursor of the A-form, because thailandin A is further rhamnosylated. Both compounds show activity against pathogenic fungal strains with minimum inhibitory concentrations ranging between 16–32 μg/mL [ 8 ].…”

“…In addition, thailandin A is O -rhamnosylated at position C15, where thailandin B has only a hydroxyl group. Both compounds show significant inhibition of anthracnose fungi and pathogenic yeast strains [ 8 ].…”

The secondary metabolites of rare actinomycetes: chemistry and bioactivity

“…Additionally, the pathogenic yeasts Candida albicans MT 2013/1, Candida parasilopsis DKMU 434 and Cryptococcus neoformans MT 2013/2 also were inhibited by the compounds (MIC values ¼ 16-32 mg mL À1 ). 86 Applying an OSMAC strategy, trying different fermentation approaches, led to the isolation of two new antioxidant actinosporin analogues, actinosporin C (285) and D (286). Differently from a general culture, a culture of (Fig.…”

“…2EPS was isolated. The strain produced three known 26 A previously undescribed g-pyrone, miaolienone (79), and a new butanolide, miaolinolide (80), along with 13 known compounds (81)(82)(83)(84)(85)(86)(87)(88)(89)(90)(91)(92)(93), were obtained from Actinomadura miaoliensis BCRC 16873, which was isolated from a soil sample collected in Miaoli County, Taiwan. Compounds 79 and 80 could inhibit the production of TNF-a in U937 cells in vitro signicantly, and the IC 50 values were 0.59 and 0.76 mM, respectively.…”