Strychnos toxifera is a poisonous plant used by Amazon indians in the manufacture of curare poison [1]. Its toxicity is clue to indole alkaloids, which are the major constituents of this poison [2]. Endophytes are considered outstanding and underexplored sources of novel chemically diverse and bioactive compounds. These microorganisms can be detected at a particular moment within the tissues of apparently healthy plant hosts, and they have been found in all plant species examined to date [3]. As they occupy unique biological niches, the complex web of interactions with other endophytes and with the host might give rise to new chemical diversity and bioactive compounds [4]. In the course of screening for biologically active agents from Amazonian endophytic fungi [5], Penicillium chrysogenum, an endophytic fungus from the trunk of S. toxifera, was chosen for further phytochemical investigation.

The MeOH extract of the mycelial mass from P. chrysogenum was subjected to chromatographic separation to afford four steroids [6] [ergosterol (1), brassicasterol (2), ergosterol peroxide (3), and cerevisterol (4)], two aromatic acids [7] [cinnamic acid (5) and p-hydroxybenzoic acid (6)], and three mycotoxins [8] [kojic acid (7), penicillic acid (8), and patulin (9)]. These compounds were obtained and characterized by a comparison of their physical and spectral data (UV, IR, NMR and MS), with values in the literature.

S. toxifera was collected from Manaus, Brazil in July, 2008. The strain of P. chrysogenum was obtained, purified, and identified from the healthy tissues of the trunk using a previous methodology [9]. After cultivation in liquid media [5], the mycelial mass (1.1 kg) was extracted with MeOH (3 × 500 mL) at room temperature, and a MeOH extract (30.4 g) was obtained upon concentration under reduced pressure. The MeOH extract was chromatographed over silica gel (600 g, 70–230 mesh) using n-hexane containing increasing amounts of EtOAc to obtain nine fractions. Fraction 1 (321.7 mg) was purified on a silica gel column with n-hexane–CHCl3 with increasing gradient, yielding 1 (22 mg), 2 (7 mg), 3 (12 mg), and 4 (9 mg). Fraction 5 (507 mg) was subjected to silica gel chromatography with CHCl3–MeOH with increasing gradient, yielding 5 (4 mg), 6 (11 mg), 7 (89 mg), 8 (9 mg), and 9 (5 mg).

figure a