Nardosinane-Type Sesquiterpenoids from the Formosan Soft Coral Paralemnalia thyrsoides

Abstract

Five new nardosinane-type sesquiterpenoids, paralemnolins Q–U (1–5), along with three known compounds (6–8), were isolated from the Formosan soft coral Paralemnalia thyrsoides. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods, and the absolute configuration of 1 was determined by the application of Mosher’s method on 1. Among these metabolites, 1 and 3 are rarely found nardosinane-type sesquiterpenoids, possessing novel polycyclic structures. Compounds 1, 3, 6 and 7 were found to possess neuroprotective activity.

Parathyrsoidins A–D, Four New Sesquiterpenoids from the Soft Coral Paralemnalia thyrsoides

“…According to the aforementioned observations, the structure of parathyrsoidin A ( 1 ) was revealed to be the C-11 epimer of 2-deoxy-7- O -methyllemnacarnol. In order to rule out the possibility of 1 being an isolation artifact, a sample of 2-deoxylemnacarnol [5] obtained from Prof. Sheu laboratory was kept at room temperature for three day in the presence of RP-18 gel in MeOH. However, the formation of 2-deoxy-7- O -methyllemnacarnol was not observed.…”

“…Soft corals belonging to the genus Paralemnalia have been proved to be a rich source of sesquiterpenoids [1,2,3,4,5,6,7,8,9,10,11,12,13]. Our recent study of the chemical constituents of the soft coral P. thyrsoides has yielded a cytotoxic bisnorsesquiterpenoid, paralemnolide A [13].…”

(1R,2S,4S,4aS,8S,8aS)-4-Hydroxy-8,8a-dimethyl-10-oxo-2,3,4,7,8,8a-hexahydro-1H-4a,1-(epoxymethano)naphthalen-2-yl acetate

“…For the synthesis, see: Selaimia-Ferdjani et al (2013). For the biological activity of the natural lactone Paralemnolide A analogue of the title compound, see: Wang et al (2012) and of related nardosinane sesquiterpene derivatives, see: Bishara et al (2008); Huang et al (2011); Petit et al (2004); Lu et al (2011). For related nardosinane sesquiterpenes whose biological activity has not been investigated, see: El-Gamal et al (2005); Huang et al (2006); Wang & Duh (2007); Wang et al (2010).…”

“…Nonius KappaCCD diffractometer Absorption correction: gaussian (JANA2006; Petříček et al, 2006) T min = 0.967, T max = 0.972 12282 measured reflections 3328 independent reflections 2774 reflections with I > 2(I) Data collection: COLLECT (Nonius, 1998); cell refinement: EVALCCD (Duisenberg et al, 2003); data reduction: COLLECT (Nonius, 1998); program(s) used to solve structure: SIR2004 (Burla et al, 2005); program(s) used to refine structure: JANA2006 (Petříček et al, 2006); molecular graphics: Mercury (Macrae et al, 2006); software used to prepare material for publication: JANA2006. (Bishara et al 2008;Huang et al 2011;Lu et al 2011;Petit et al 2004;Wang et al 2012) while the potential of others remains to be explored (El-Gamal et al 2005;Huang et al 2006;Wang and Duh 2007;Wang et al 2010). In our continuing interest in the total synthesis of biologically active compounds, we have recently proposed a synthetic strategy to access such sesquiterpene derivatives.…”

(+)-Pathylactone A, a New Natural Nor-sesquiterpenoid from the Octocoral Paralemnalia thyrsoides

“…The Formosan octocoral Paralemnalia thyrsoides (Ehrenberg 1834) (family Nephtheidae, order Alcyonacea, class Anthozoa, phylum Cnidaria) comprises large quantities of sesquiterpenoid analogues, which often have complex structures and bioactivities [1][2][3][4][5][6][7][8]. Our current studies on the constituents of P. thyrosides, a new norsesquiterpenoid, (+)-pathylactone A (1) and a known analogue, napalilactoe (2) [9] (Figure 1), were isolated.…”