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Seven highly oxidized steroids, taccachatrones A-G ( 1 - 7 ), together with four known taccalonolides ( 8 - 11 ), were characterized from the rhizomes of Tacca chantrieri . The structures of 1 - 7 were established on the basis of spectroscopic data analysis, while the absolute configurations were determined by single-crystal X-ray diffraction. Compounds 1 - 4 may be derived from taccalonolide derivatives by the degradation of three carbon atoms. Compounds 7 , 8 , 10 , and 11 exhibited cytotoxicity to human cancer cell lines, indicating that the presence of a lactone moiety, as well as a double bond between C-22 and C-23, might play key roles in mediating their cytotoxicity.

A chemical investigation on the EtOAc extract of the endophytic fungus Eutypella scoparia SCBG-8 led to the isolation of eight new sesquiterpenes eutyscoparins A-H ( 1-8 ), one C-28 steroid eutyscoparene A ( 9 ), one triterpenoid eutyscoparene B ( 10 ), six known terpenoids, and two known steroids. Their structures including absolute configurations were established on the basis of spectroscopic data analysis, single-crystal X-ray diffraction experiments, and electronic circular dichroism (ECD) calculations. Compound 7 displayed antibacterial activity against S. aureus and MRSA (methicillin-resistant Staphylococcus aureus ) with MIC values of 6.3 μg/mL.

Swinhoeisterols C-F (1-4), four new steroids having a rearranged 6/6/5/7 ring system, were isolated from the Xisha sponge Theonella swinhoei, together with the known analogue swinhoeisterol A (5). Their structures were determined based on spectroscopic analysis, TDDFT-ECD and optical rotation calculations, and biogenetic correlations. In an in vitro assay, compound 1 showed an inhibitory effect on (h)p300 with an IC 50 value of 8.8 μM, whereas compounds 2-4 were not active.

Ten new polyhydroxysteroidal glycosides, anthenosides L-U (1-10), with rare positions of carbohydrate fragment attachments, were isolated from the starfish Anthenea aspera. The structures of 1-10 were established by NMR and ESIMS techniques as well as by chemical transformations. The unoxidized Δ 22 -24-nor-cholestane (1), (24S)-Δ 22 -24-methylcholestane (2-5), and Δ 22 -cholestane (7) side chains of the steroidal aglycons, 3-O-methyl-β-d-galactofuranosyl residue (2, 8), and 5α-cholest-8(14)-ene-3α,7β,16α-trihydroxysteroidal nucleus (9, 10) have not been found previously in starfish polar steroidal compounds. The mixture of glycosides 9 and 10 showed hemolytic activity with an EC 50 = 8 μM. Compound 4 at a dose of 10 μM exhibited a potential immunomodulatory action, decreasing by 24% the intracellular ROS content in RAW 264.7 murine macrophages, induced by pro-inflammatory endotoxic lipopolysaccharide from E. coli.

For the purpose of advancing knowledge of the structural variations available in the natural cephalostatins contained in the marine worm Cephalodiscus gilchristi, the isolation and structure of the 20th member (1) has been accomplished (10(-7) % yield). In turn cephalostatin 20 (1) proved to be enough for an initial SAR study comprising six important human cancer cell lines. A parallel objective was aimed at the possible discovery of a natural cephalostatin with a more accessible structure for total synthesis and/or synthetic modifications, but with powerful cancer cell growth inhibition.

Five new steroid glycosides, luzonicosides B-E (2-5), belonging to a rare structure group of marine glycosides, containing carbohydrate moieties incorporated into a macrocycle, and a related open carbohydrate chain steroid glycoside, luzonicoside F (6), were isolated from the starfish Echinaster luzonicus along with the previously known cyclic steroid glycoside luzonicoside A (1). The structures of compounds 2-6 were established by extensive NMR and ESIMS techniques as well as chemical transformations. Luzonicoside A (1) at concentrations of 0.01-0.1 μM was shown to be potent in lysosomal activity stimulation, intracellular ROS level elevation, and NO synthesis up-regulation in RAW 264.7 murine macrophages. Luzonicoside D (4) was less active in these biotests.

Veratrum nigrum is recognized as a medicinal plant used for the treatment of hypertension, stroke, and excessive phlegm. Chemical investigation of the roots and rhizomes led to the isolation of five new steroidal alkaloids, jervine-3-yl formate (1), veramarine-3-yl formate (2), jerv-5,11-diene-3β,13β-diol (3), (1β,3β,5β)-1,3-dihydroxyjervanin-12(13)-en-11-one (4), and veratramine-3-yl acetate (5). Compounds 1 and 5 exhibited potent inhibitory activity (11.3 and 4.7 μM, respectively) against protein tyrosine phosphatase 1B (PTP1B), which has emerged as a viable target for treatment of type 2 diabetes mellitus. On the basis of their PTP1B inhibitory activity, the compounds were evaluated for their potential to enhance glucose uptake in C2C12 skeletal muscle cells. The insulin-stimulated glucose uptake was enhanced upon treatment with compounds 1 and 5 (10 μM) by 49.9 ± 6.5% and 56.0 ± 9.7%, respectively, in a more potent manner than that with the positive control rosiglitazone (47.3 ± 3.4% at 30 μM). These results suggest that steroidal alkaloids serve as practical antidiabetes mellitus leads capable of enhancing glucose uptake.

Chemical investigation of a Korean marine sponge, Monanchora sp., led to the isolation of three new steroids (1-3). Compounds 1 and 2, designated as monanchosterols A and B, respectively, represent the first examples of steroids possessing the bicyclo[4.3.1] A/B ring system from a natural source. Compounds 1-3 were investigated for their anti-inflammatory activity by evaluating their inhibitory effects on the mRNA expression of IL-6, TNF-α, and COX-2 in the LPS-stimulated murine RAW264.7 macrophage cells. Compounds 2 and 3 exhibited significant inhibitory effects on the mRNA expression of IL-6 without notable cytotoxicity to the cells in a dose-dependent manner.

Bioinformatic analysis of data from the NCI-60 cell cytotoxicity screen revealed a subset of extracts that showed selective cytotoxic activity toward human colon carcinoma cell lines. Bioassay-guided fractionation of a colon cancer selective extract from a Philippines collection of the marine sponge Corticium niger provided two new steroidal alkaloids, plakinamines N (1) and O (2), along with two known compounds of the plakinamine class (3, 4). The structures of these compounds were elucidated by interpretation of combined MS and NMR spectroscopic data. Plakinamines N (1), O (2), and J (4) were tested for antiproliferative activity in the NCI-60 screen, and they showed enhanced inhibitory effects against all of the colon cell lines with mean GI50 values of 11.5, 2.4, and 1.4 μM, respectively.