Eleven New 2-Pyrones from a Fungi Imperfecti, Trichurus terrophilus, Found in a Screening Study Guided by Immunomodulatory Activity

Abstract

In our screening program on immunomodulatory constituents from fungi, many immunosuppressive metabolites have already been isolated from various Ascomycetes belonging to Gelasinospora, Diplogelasinospora, Microascus, Emericella, Eupenicillium, Chaetomium, and Zopfiella. 2) The EtOAc extract of a Fungi Imperfecti, Trichurus terrophilus SWIFT & POVAH showed an appreciable suppressive effect on the proliferation (blastogenesis) of mouse splenic lymphocytes stimulated with mitogens, concanavalin A (Con A), and lipopolysaccharide (LPS). Solvent partitions followed by repeated chromatographic fractionations of the extract, guided by immunosuppressive activity, afforded eleven new compounds tentatively named TT-1-11 (1-11). This paper deals with the structures and immunosuppressive activities of these constituents.The EtOAc extract of T. terrophilus IFM4606 3) cultivated on sterilized moistened-rice medium suppressed the Con Ainduced proliferation of mouse splenic lymphocytes by 99.6% at 50 mg/ml. The EtOAc extract was partitioned between n-hexane and water into an n-hexane layer and an aqueous suspension. The aqueous suspension was further partitioned between EtOAc and water into an EtOAc layer and an aqueous layer [yields (%) of the n-hexane, EtOAc, and aqueous layers after evaporation of the solvents from the EtOAc extract: 73.2, 17.4, and 2.3, respectively]. The IC 50 values of the n-hexane, EtOAc, and aqueous layers against the Con A-induced proliferation were 9.7, 2.5, and Ͼ50 mg/ml, respectively. Repeated chromatographic fractionations monitored by the immunosuppressive activity of the EtOAc layer afforded four components tentatively named TT-1-4 (1-4) [yields (%) of 1, 2, 3, and 4 from the EtOAc extract: 0.26, 0.0078, 0.011, and 0.0089, respectively]. It was found out that the other strain of this fungus, T. terrophilus IMI462513) also produced 1 and its homologues in good yields. Repeated chromatographic fractionations of the EtOAc layer, which was obtained from the partition of the EtOAc extract of T. terrophilus IMI46251 in the same way as described for the partition of the EtOAc extract of T. terrophilus IFM4606, gave seven new constituents tentatively named TT-5-11 (5-11) in addition to 1-4 [yields (%) of 1, 2, 3, 4, 5, a mixture of 6 and 7 (6/7), 8, 9, 10, and 11 from the EtOAc extract: 1. C-NMR spectral data of 1 (see Table 1) including the two dimensional 1 H-1 H shift correlation (COSY), 1 H-detected heteronuclear correlation through multiple quantum coherence (HMQC), and 1 H-detected heteronuclear multiple-bond correlation (HMBC) NMR data suggested a planar structure for TT-1. On acetylation with acetic anhydride in pyridine, 1 gave diacetate (12). Comparison of the 1 H-and 13 C-NMR spectral data of 1 with those of 12 (Table 1) in reference to the acetylation shift rule, 4,5) confirmed the planar structure of TT-1 (1a) (see Fig. 1 (Table 1) with those of 1 revealed that the unsaturated CϭC bond at position 3 in 1 was saturated in 2, indicating that the planar structure of TT-2 was expressed as 2 (F...

Nine Constituents Including Six Xanthone-Related Compounds Isolated from Two Ascomycetes, Gelasinospora santi-florii and Emericella quadrilineata, Found in a Screening Study Focused on Immunomodulatory Activity

“…[This method is based on the formation ratio of MTT-formazan from exogenous 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) in lymphocytes]. 1) Chemical shifts are expressed in d (ppm) values from tetramethylsilane (TMS) as an internal standard.…”

“…The eight constituents GS-3 (3), 2 (2), 4 (4), 1 (1), and EQ-4 (6), 6 (7)-8 (9) were obtained from E. quadrilineata in the following yields [yields (%) of 3, 2, 4, 1, 6, 7, 8, and 9 from the EtOAc extract: 0.060, 1.3, 0.51, 1.1, 0.77, 0.15, 0.089, and 0.025, respectively]. Among the nine constituents 1-9 from the two fungi, 1, 5, and 7 showed significantly immunosuppressive activity (IC 50 value of 1, 5, and 7 against the Con A-induced proliferation: 0.15, 6.5, and 5.1 mg/ml, respectively).…”

Gombapyrones, new α-pyrone metabolites produced by Streptomyces griseoruber Acta 3662

“…13 Furthermore, 11 a-pyrones, tentatively named TT-1-11, have been isolated from the imperfect fungus Trichurus terrophilus, from which compounds TT-1-4 exhibited considerably high immunosuppressive activities. 14 The a-pyrone derivative, 6-[(E)-hept-1-enyl]-a-pyrone, isolated from a marine Botrytis species, exhibited a tyrosinase inhibitory activity with an IC 50 value of 4.5 mM, which is more active than kojic acid showing an IC 50 value of 15.5 mM, which is currently being used as a preservative in cosmetics and food. 15 However, the most structurally related compounds are probably lehualides, which are isolated from a marine sponge of the genus Plakortis.…”

Xylanilyticolides A–C, Three New Compounds from Cultures of the Actinomycete Promicromonospora xylanilytica YIM 61515

“…The above data coupled with a literature survey indicated that compound 1 was analogous to the reported compound rasfonin, an apoptosis inducer in Ras -dependent cells isolated from the fungus Talaromyces sp. [ 10 ]. Comparing with the reported structure, the two distinct differences in compound 1 were the reduction of olefinic bond in C-3 and the substitution of a methoxy in C-4.…”