The first seco-asbestinin: A novel class of diterpene from the Caribbean gorgonian Briareum asbestinum (Pallas)

seco-Briarellinone and Briarellin S, Two New Eunicellin-Based Diterpenoids from the Panamanian Octocoral Briareum asbestinum

“…Fraction E (82.7 mg) was purified by HPLC (reverse phase Synergy-Fusion column eluted with a gradient of 60%–100% MeCN in water in 60 min at 1 mL/min) to yield 15 fractions. Fraction 10 yielded 10 mg of pure seco -asbestinin ( 3 ) [12]. Fraction F was concentrated (266.2 mg) and further chromatographed on silica gel eluted with a stepwise gradient of CHCl 3 - i PrOH (150:1, 100:1, 50:1) followed by CHCl 3 -EtOH (25:1, 10:1, 1:1) to yield 22 fractions (1–22).…”

Isolation and Structures of Sixteen New Asbestinin Diterpenes from the Caribbean Gorgonian Briareum asbestinum

“…Finally, compound 20 was isolated in trace amounts during purification of compound 9 by successive ODS-Si and normal-phase hplc. With its unprecedented stmctural features, diterpene 20 is thus far the only known representative of the secoasbestinin class of ether-cyclized diterpenes (11). crew of the R/V Isla Magueyes for their assistance during a trip to Mona Island and to Javier J. Soto for valuable assistance during the early stages of this work.…”

“…The residue obtained from the hexane extract upon sizeexclusion chromatography gave a group of fractions containing a complex mixture of several major and minor metabolites. These were separated by repeated cc and hplc to yield nine new asbestinins, asbestinins [11][12][13][14][15][16][17][18][19] [1, 3-5, 7-11}, along with the known asbestinin-6 [2} and asbestinin-7 [6} (3). When specimens of B. asbestinum collected off the east coast of Puerto Rico (Palomino Island) were subjected to identical extractive procedures, four new asbestinins were isolated, namely asbestinins 20-23 [12-15}, which were accompanied by three new 4-deoxyasbestinin diterpenes [16-18}, and the known 4-deoxyasbestinins A-D (1).…”

Novel Cytotoxic Diterpenes, Excavatolides A−E, Isolated from the Formosan Gorgonian Briareum excavatum

“…Gorgonians (order Gorgonacea, phylum Cnidaria) and soft corals (Alcyonacea, phylum Cnidaria) have been proven to be rich sources of structurally novel secondary metabolites. Previous studies on gorgonian corals of the genus Briareum resulted in the isolation of a series of novel diterpenoids, represented by briaranes, − and asbestinins. − Diterpenoids of the briarane class have also been isolated from other coelenterates such as a true soft coral, a sea pansy, and sea pens, − and continue to attract the attention of investigators because of the structural complexity and interesting biological activity (e. g., cytotoxic, ,, antiinflammatory, ,, antiviral, , and insecticidal 3 ) associated with several compounds of this type. We have also previously isolated five cytotoxic briaran diterpenes from a Formosan gorgonian Briareum sp .…”