New steroidal saponins from the sponge Erylus lendenfeldi

Abstract

Our search for biologically active marine natural products has led to the isolation of two new steroidal saponins, eryloside K (2) and eryloside L (3) together with the known antitumor and antifungal glycoside eryloside A (1) from the organic extract of the sponge Erylus lendenfeldi (Geodiidae) collected in the Red Sea. The structures of the new compounds were elucidated on the basis of comprehensive spectral analyses ( 1 H, 13 C, COSY, HMQC, HMBC and TOCSY NMR) as well as GC/MS analysis to infer the absolute stereochemistry of the sugar moieties. Eryloside K (2) is the 24,25-didehydro congener of 1, while eryloside L (3) features an unusual 8α,9α-epoxy-4α-methyl-8,9-secocholesta-7,9(11),14-triene skeleton which appears to be unprecedented in nature. Eryloside A (1) displayed antibacterial activity against Bacillus subtilis and Escherichia coli together with antifungal activity against Candida albicans.

Glycosides from Marine Sponges (Porifera, Demospongiae): Structures, Taxonomical Distribution, Biological Activities and Biological Roles

“…The containing 24(25)-double bond in its aglycone eryloside K ( 45 ) was independently and almost simultaneously isolated by Fouad et al . [ 29 ] at the studies on the same sponge, collected off the Jordan coast in the Gulf of Aqaba, the Red Sea. Eryloside L ( 46 ) was structurally identified by Sandler et al .…”

A new lanostane-type triterpene and sesquiterpene lactones fromVernonia leopoldiiand theirin vitrocytotoxicity

“…Careful comparison of the 1 H and 13 C chemical shift values of similar partial structures within the side chain of 3 with data published for both possible isomers (R & S) for which Mosher esters and NOE experiments have been carried out, revealed that the carbon atom bearing a-configured hydroxyl group and its proton are always shielded by . 3 -6 and 0.38-0.39 ppm, respectively over the b-isomer (Fouad et al 2004;Liu & Abreu 2006;Wang et al 2008;Nakata et al 2009;Sultana & Sultana 2009). This placed the hydroxyl group as (a) and suggested the configuration at C-23 as (S).…”

Bioactive Sesterterpenes and Triterpenes from Marine Sponges: Occurrence and Pharmacological Significance

“…Eryloside A ( 118 ) was the first eryloside congener isolated from the Red Sea sponge Erylus lendenfeldi (class Demospongiae; order Choristida; family Geodiidae) [ 107 ]. Twenty eight additional erylosides (A–F, F 1 –F 7 , G–V) have been reported from different species of the genus Erylus including E. goffrilleri [ 109 , 114 ], E. formosus [ 110 , 113 ], E. nobilis [ 111 ], in addition to another collection of E. lendenfeldi [ 112 ].…”

“…Erylosides K ( 123 ) and L ( 124 ) have been obtained together with 118 from another collection of the Red Sea marine sponge Erylus lendenfeldi [ 112 ]. While 123 was identified as the 24,25-didehydro congener of eryloside A, eryloside L ( 124 ) incorporated a naturally unprecedented 8 α ,9 α -epoxy-4 α -methyl-8,9-secocholesta-7,9(11),14-triene skeleton [ 112 ]. Erylosides A ( 118 ) and K ( 123 ) led to a 50% mortality rate in the brine shrimp assay at a concentration of 0.14 mM.…”

“…Erylosides A ( 118 ) and K ( 123 ) led to a 50% mortality rate in the brine shrimp assay at a concentration of 0.14 mM. Whereas, eryloside L ( 124 ) was inactive at the same concentration [ 112 ].…”