Genus Chloranthus: A comprehensive review of its phytochemistry, pharmacology, and uses

Chemistry and bioactivity of lindenane sesquiterpenoids and their oligomers

“…The carbon skeletons and plausible biosynthetic pathways of LS oligomers indicate that [4 + 2] cycloaddition, 28,29 [2 + 2] cycloaddition, 30 [6 + 6] cycloaddition, 30 oxygen-involved [2 + 2 + 2] cycloaddition, 34,36,37 C linear linkage from Micheal addition, 66 and O linear linkage from ether or ester bonds 67 are the main polymerization patterns in these homo-and heterooligomers (Fig. 2), which can be explained by the presence of highly conjugated units (D 15(4),5(6),7 (11) , D 15(4),5 (6) , D 11, (13) , D 7(11),8(O) , D 7(11),13(O) , D 6 (7) , D 7 (11) , and D 8 (9) ) in LSs. [28][29][30]52 Taking the most abundant and classical [4 + 2] cycloaddition homo-dimer as an example, it is formed by the intermolecular Diels-Alder reaction between D 15(4),5 (6) and D 8 ′ (9 ′ ) .…”

“…Although LSs have been discovered for 100 years and 354 natural LSs with 50 diverse carbon skeletons have been reported; [5][6][7][8][9][10][31][32][33][34][35][36][37] however, a clear and rational structural clas-sication for LSs and their oligomers is lacking. Thus, a classi-cation based on the basic framework and plausible biogenetical pathways of LSs will be proposed in this review.…”

“…Compounds 64-82 are characteristic LS monomers with an a,b-unsaturated g-lactone and additional D 8 (9) enolic double bond. In this group, chloranthalactone A (64), 119 chlojaponilactone B (65), 114 onoseriolide B (66), 120,121 sibirolide B (67) 18 and onoseriolide senecioate (68) 19 possess D 15(4) , D 7 (11) , and D 8 (9) double bonds, whereas sarcandralactone D (69) 116 has an isomerized D 4 (5) .…”

“…[5][6][7][8][9][10] Since the rst identication of lindeneol from L. strychnifolia in 1925, 5,11 354 natural LS analogs have been discovered in plants from the Lauraceae, 5,6,12,13 Chloranthaceae, [6][7][8]10,[14][15][16][17] Asteraceae, [18][19][20][21][22][23] and Cyperaceae 24 families, and also the marine animal gorgonian corals. 25,26 Due to the highly conjugated double bonds in LSs, 6,7,27 188 LSs exist as homo-oligomers with different skeletons through diverse addition and rearrangement reactions, [5][6][7][8][9][10] such as Diels-Alder [4 + 2] cycloaddition, 28,29 [2 + 2] cycloaddition, 30 and [6 + 6] cycloaddition. 30 It is worth noting that LS and non-LS units (e.g., monoterpene and geranylbenzofuranone) can form heterooligomers with unprecedented structural diversity, which have remarkable differences compared with that of other sesquiterpenoids.…”

“…[47][48][49][50] In particular, 13 ′ -Omethyl succinylshizukaol C has been reported to show about 1000-fold stronger antimalarial activity than that of artemisinin. 48,50 Considering their diverse skeletons and strong bioactivities, [5][6][7][8][9][10]44,45,[47][48][49][50] the total synthesis of LSs and their oligomers has also attracted signicant interest from organic chemists, and thus far, complex and bioactive oligomers with seven types of skeletons have been synthesized by several groups. [51][52][53][54] The aforementioned information indicates that signicant progress has been achieved in the last 100 years regarding the chemistry and bioactivity of LSs and their oligomers.…”