Antifungal and antibacterial metabolites from an endophytic Aspergillus sp. associated with Melia azedarach

Seven known metabolites, dianhydro-aurasperone C (1), isoaurasperone A (2), fonsecinone A (3), asperpyrone A (4), asperazine (5), rubrofusarin B (6) and (R)-3-hydroxybutanonitrile (7), were isolated from the culture of Aspergillus sp. KJ-9, a fungal endophyte isolated from Melia azedarach and identified by spectroscopic methods. All isolates were evaluated in vitro against several phytopathogenic fungi (Gibberella saubinetti, Magnaporthe grisea, Botrytis cinerea, Colletotrichum gloeosporioides and Alternaria solani) and pathogenic bacteria (Escherichia coli, Bacillus subtilis, Staphyloccocus aureus and Bacillus cereus). Compounds 3 and 7 were active against almost all phytopathogenic fungi tested with minimum inhibitory concentration (MIC) range of 6.25–50 μM. Moreover, compound 3 was active against all pathogenic bacteria with MIC in the range of 25–100 μM. Compound 7 is a rare new natural product isolated from a natural source for the first time, and the detailed NMR data of 1 were first assigned.