Meroditerpenoids from the Brown Alga Sargassum siliquastrum

Abstract

Eleven new meroditerpenoids (7-11, 14-17, 19, 20) and nine known compounds (1-6, 12, 13, 18) were isolated from the brown alga Sargassum siliquastrum. Combined chemical and spectroscopic analyses revealed a common tetraprenyl hydroquinone structure; these compounds belonged to the nahocol, isonahocol, and sargahydroquinoic acid classes. The dihydroquinone moiety of 20 was unique and unprecedented in a brown alga. Stereochemical assignments were made for several of the known compounds based on their chemical reactivity. These compounds exhibited moderate to significant radical-scavenging activity as well as weak inhibitory activities against sortase A and isocitrate lyase.

Chromanols from Sargassum siliquastrum and Their Antioxidant Activity in HT 1080 Cells

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23] The brown alga S. siliquastrum is commonly found in the coastal area of the Korean peninsula. Recently, some studies have addressed that S. siliquastrum possesses a number of meroditerpenoids of the chromene and related structural class [24][25][26][27] and some of these meroditerpenoids exhibit biological activities such as cytotoxicity, antioxidant capacity, vasodilatation, inducement of the larval settlement of the hydrozoan, and inhibition of butylcholine esterase. [28][29][30] In the course of our countinuing search for bioactive compounds from marine algae, the brown alga S. siliquastrum was collected along the offshore of Jeju Island, Korea.…”

Secondary Metabolites and Biological Activity of Invasive Macroalgae of Southern Europe

“…we can also find various compounds [48,54,56,61,78,79,80,81,82]. Their structures are in Figure 12 and occurrences are in Table 4.…”

“…[54,55,56,57,58,59,60,61,62,63,64,65]. Their structures are in Figure 10 and occurrences are in Table 2.…”

“…From S. serratifolium [60], 68 and 80 were isolated and from S. siliquastrum [61], 96 and 97 were isolated. Compound 96 showed radical-scavenging activity in DPPH assays.…”

“…From S. siliquastrum [61], compounds 143 – 159 were isolated. They showed moderate to significant radical-scavenging activity in DPPH assays.…”