Alternaria is a well-known genus of plant pathogenic fungi distributed widely in soil and air. Some of them such as A. mali, A. kikuchiana, and A. solani exhibit high pathogenicity towards apple, pear, tobacco, and potato plants . Alternaria species produce different classes of fungal toxins, which play important roles in the course of plant diseases , 

Thus, CIB researchers pointed out that as part of our ongoing investigations on the secondary metabolites of pathogenic fungi, a new 2H-pyran-2-one derivative, 3-butyryl-6-[rel-(1S, 2S)-1,2-dihydroxypropyl]-4-hydroxy-2H-pyran-2-one (1), together with three known compounds, deoxyradicinin (2) , 3-epiradicinol (3),and 3-epideoxyradicinol (4) , was isolated from the solid fermented rice culture of A. sp. CIB 108. Their structures were determined by spectroscopic analyses.

Also, the structure of 1 was confirmed by the single crystal X-ray diffraction. Compound 1 is the first 2H-pyran-2-one metabolite from the genus Alternaria with ring opened between C-9 and C-4. n addition, compounds 1–4 were tested for cytotoxicity and antibacterial activity.

CIB researchers isolated a new compound, 3-butyryl-6-[rel-(1S, 2S)-1,2-dihydroxypropyl]-4-hydroxy-2H-pyran-2-one (1), from the solid fermented rice culture of Alternaria sp. CIB 108, along with three known ones, deoxyradicinin (2), 3-epiradicinol (3), and 3-epideoxyradicinol (4). Their structures were elucidated on the basis of spectroscopic data. The single crystal X-ray diffraction was applied to further clarify the structure of 1. Furthermore, compounds 1–4 possessed no cytotoxicity against several cell lines (HeLa, HepG2, and Ros) and showed no antibacterial activity at 40 μmol/L.

CAS Chengdub Institue of Biology Prof. LI Guoyou's team studied this job, and got grants from NSFC and  Chinese Academy of Sciences. More details have been published in CHINESE CHEMICAL LETTERS.