New triterpenoidal saponins from Koelreuteria paniculata.

Bioassay guided fractionation and chemical investigation of the ethanolic extract of the aerial parts of Koelreuteria paniculata Laxm. (Sapindaceae), resulted in the isolation and identification of three new triterpenoid saponins 1-3 named Paniculatosoid A-C, along with eleven known compounds. The structures of the isolated compounds were elucidated using 1D and 2D NMR experiments, HRESIMS, and comparison with literature data. The occurrence of tridesmosidic saponin is reported for the first time from family Sapindaceae, as well as it is rarely found in natural saponins. Compounds 4-13 were evaluated for their antibacterial, antifungal, antimalarial and antileishmanial activities. Compound 12 showed weak antibacterial activity against Escherichia coli with an IC50 value of 101 µM. Compounds 12 and 13 showed antimalarial activity against chloroquine-sensitive (D6) Plasmodium falciparum protozoan with IC50 values of 6.46 and 6.95 µM, and against chloroquine-resistant (W2) Plasmodium falciparum protozoan with IC50 values of 9.34 and 4.18 µM.

Asphodosides A-E, anti-MRSA metabolites from Asphodelus microcarpus.

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm. et Viv. (Xanthorrhoeaceae or Asphodelaceae) resulted in isolation of five compounds identified as asphodosides A-E (1-5). Compounds 2-4 showed activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 1.62, 7.0 and 9.0µg/mL, respectively. They also exhibited activity against Staphylococcus aureus (non-MRSA) with IC50 values of 1.0, 3.4 and 2.2µg/mL, respectively. The structure elucidation of isolated metabolites was carried out using spectroscopic data (1D and 2D NMR), optical rotation and both experimental and calculated electronic circular dichroism (ECD).

Antileukemic α-pyrone derivatives from the endophytic fungus Alternaria phragmospora.

Four new (1-4) and two known (5 and 6) α-pyrone derivatives have been isolated from Alternaria phragmospora, an endophytic fungus from Vinca rosea, leaves. The isolated compounds were chemically identified to be 5-butyl-4-methoxy-6-methyl-2H-pyran-2-one (1), 5-butyl-6-(hydroxymethyl)-4-methoxy-2H-pyran-2-one (2), 5-(1-hydroxybutyl)-4-methoxy-6-methyl-2H-pyran-2-one (3), 4-methoxy-6-methyl-5-(3-oxobutyl)-2H-pyran-2-one (4), 5-(2-hydroxyethyl)-4-methoxy-6-methyl-2H-pyran-2-one (5), and 5-[(2E)-but-2-en-1-yl]-4-methoxy-6-methyl-2H-pyran-2-one (6). Compounds 2 and 4 showed moderate antileukemic activities against HL60 cells with IC50 values of 2.2 and 0.9 µM and against K562 cells with IC50 values of 4.5 and 1.5 µM, respectively.

Nigrosphaerin A a new isochromene derivative from the endophytic fungus Nigrospora sphaerica.

Nigrosphaerin A, a new isochromene derivative (1), was isolated from the endophytic fungus Nigrospora sphaerica and chemically identified as 3-(3,4-dihydroxyphenyl)-4,6,8-trihydroxy-1H-isochromen-1-one-6-O-ß-d-glucopyranoside. In addition nineteen known compounds (2-20) were isolated from the same fungus and chemically identified. Compounds (1-3, 5, and 7-16) were isolated for the first time from this fungus. In vitro antileukemic, antileishmanial, antifungal, antibacterial and antimalarial activities of (1-20) were examined. Compounds 5, 7, 9 and 10 showed good antileukemic activity against HL60 cells with IC50 values of 0.03, 0.39, 0.2 and 0.4 µg/mL, respectively and against K562 cells with IC50 values of 0.35, 0.35, 0.49 and 0.01 µg/mL, respectively. Compounds 3, 4 and 6 showed moderate antileishmanial activity with IC50 values of 30.2, 26.4 and 36.4 µg/ml, respectively. Compound 7 showed moderate antifungal activity against Cryptococcus neoformans with IC50 value of 14.8 µg/mL.

Isolation and characterization of new secondary metabolites from Asphodelus microcarpus.

Phytochemical study of the ethanolic extract of Asphodelus microcarpus Salzm. et Viv. (Asphodelaceae) resulted in the isolation of two new compounds, methyl-1,4,5-trihydroxy-7-methyl-9,10-dioxo-9,10-dihydroanthracene-2-carboxylate (1), and (1R) 3,10-dimethoxy-5-methyl-1H-1,4-epoxybenzo[h]isochromene (2) as well as three known compounds; 3,4-dihydroxy-methyl benzoate (3), 3,4-dihydroxybenzoic acid (4), and 6-methoxychrysophanol (5). Compound 1 showed a potent activity against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus aureus with IC50 values of 1.5 and 1.2 µg/mL, respectively. Compound 3 showed antileishmanial activity with an IC50 value of 33.2 µg/mL. Compound 2 is the first isochromene possessing a highly strained 1,4-epoxy moiety. The structure elucidation of isolated metabolites was carried out using spectroscopic data, the absolute configuration of 2 based on optical rotation and electronic circular dichroism experiments and calculations.

Biologically active secondary metabolites from Asphodelus microcarpus.

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm.et Vivi (Asphodelaceae) resulted in the isolation of one new metabolite, 1,6-dimethoxy-3-methyl-2-naphthoic acid (1) as well as nine known compounds: asphodelin (2), chrysophanol (3), 8-methoxychrysophanol (4), emodin (5), 2-acetyl-1,8-dimethoxy-3-methylnaphthalene (6), 10-(chrysophanol-7'-yl)-10-hydroxychrysophanol-9-anthrone (7), aloesaponol-III-8-methyl ether (8), ramosin (9) and aestivin (10). The compounds were identified by 1D and 2D NMR and HRESIMS. Compounds 3, 6 and 10 were isolated for the first time from this species. Compounds 3 and 4 showed moderate to weak antileishmanial activity with IC50 values of 14.3 and 35.1 microg/mL, respectively. Compound 4 exhibited moderate antifungal activity against Cryptococcus neoformans with an IC50 value of 15.0 microg/mL, while compounds 5, 7 and 10 showed good to potent activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 6.6, 9.4 microg/mL and 1.4 microg/mL respectively. Compounds 5, 8 and 9 displayed good activity against S. aureus with IC50 values of 3.2, 7.3 and 8.5 microg/mL, respectively. Compounds 7 and 9 exhibited a potent cytotoxic activity against leukemia LH60 and K562 cell lines. Compound 10 showed potent antimalarial activities against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum with IC50 values in the range of 0.8-0.7 microg/mL without showing any cytotoxicity to mammalian cells.