Absolute configuration and anti-tumor activity of torrubiellin B

Abstract

a b s t r a c tThe dimeric anthracene derivative torrubiellin B (1) was isolated from the endophytic fungus Acremonium sp. that had been obtained from leaves of the Mangrove plant Sonneratia caseolaris. The absolute configuration of 1 was established as (5 0 R,10 0 S,10a 0 R) for the first time on the basis of its electronic circular dichroism (ECD) spectra aided with TDDFT-ECD calculations. Torrubiellin B (1) exhibited strong anti-tumor activity when tested in vitro against several solid cancer cell lines including cells that are resistant against the widely used cytostatic drug cisplatin. The IC 50 values of 1 against cisplatin sensitive and cisplatin resistant cells were in the range of 0.2-2.6 lM depending on cell line investigated.

Exploration of Potent Cytotoxic Molecules from Fungi in Recent Past to Discover Plausible Anticancer Scaffolds

“…Bcc 28517 culture (0.46 % w/w). Compound 22 was evaluated for anti‐cancer activity against several cancerous cell lines like Cal27, Kyse510, HCC38, MDA‐MB‐231, A2780 and found potent against Cal27, HCC38, A2780 with IC 50 0.3, 0.4, 0.3 μM, respectively, in comparison to standard cisplatin, which showed IC 50 2.9, 3.5, 1.5 μM against the same cell lines [41] …”

“…Compound 22 was evaluated for anti-cancer activity against several cancerous cell lines like Cal27, Kyse510, HCC38, MDA-MB-231, A2780 and found potent against Cal27, HCC38, A2780 with IC 50 0.3, 0.4, 0.3 μM, respectively, in comparison to standard cisplatin, which showed IC 50 2.9, 3.5, 1.5 μM against the same cell lines. [41] Further, 7-Desmethylscorpinone ( 23) and 7desmethyl-6-methylbostrycoidin ( 24) from endophytic fungus Fusarium solani have shown potent cytotoxicity. The fungus was isolated from the roots of Aponogeton undulatus Roxb found in Natore, Bangladesh in 2013.…”

Synthetic Studies of the Rubellin Natural Products: Development of a Stereoselective Strategy and Total Synthesis of (+)-Rubellin C

“…Small quantities of various rubellins could be isolated from the fungi, and 13 C labeling via [U- 13 C 6 ]-glucose allowed for confirmation of an anthraquinone dimerization through isolation of the anthraquinone monomers chrysophanol ( 7 ) and helminthosporin ( 8 ) (Scheme ). An enzyme-mediated dimerization was postulated to give a bisanthraquinone species ( 17 ), which undergoes enzymatic reduction and oxidation events to provide the rubellin natural products. , Related natural products isolated from different fungi include the torrubiellins ( 13 and 14 ), melrubiellins ( 15 and 16 ), and solanrubiellins, indicating that many fungal species may have the enzymes responsible for such chemistries. − …”

“…4 A biosynthesis from R. collo-cygni was carried out by the Liebermann group in 2006. 4 Small quantities of various rubellins could be isolated from the fungi, and 13 C labeling via [U-13 C 6 ]glucose allowed for confirmation of an anthraquinone dimerization through isolation of the anthraquinone monomers chrysophanol (7) and helminthosporin (8) (Scheme 1). An enzyme-mediated dimerization was postulated to give a bisanthraquinone species (17), which undergoes enzymatic reduction and oxidation events to provide the rubellin natural products.…”

Determination of the Absolute Configuration of CN-Palladacycles by 31P{1H} NMR Spectroscopy Using (1R,2S,5R)-Menthyloxydiphenylphosphine as the Chiral Derivatizing Agent: Efficient Chirality Transfer in Phosphinite Adducts

“…In contrast to the older publications regarding the “manual conformational search”, the recent practice includes preliminary molecular mechanics (MM)-based conformational analysis followed by density functional theory (DFT) optimization of the most stable diastereomer structure in several conformations. , Most of the recent investigations directed toward the AC assignments from the chiroptical characteristics combine the experimental data with the time-dependent density functional theory (TDDFT) calculations of specific rotation values, , optical rotatory dispersion curves, electronic, , exciton-coupled, and vibrational circular dichroism spectra, , and vibrational Raman optical activity…”