Polycyclic xanthone natural products: structure, biological activity and chemical synthesis

Abstract

Polycyclic xanthone natural products are a family of polyketides which are characterized by highly oxygenated, angular hexacyclic frameworks. In the last decade, this novel class of molecules has attracted noticeable attention from the synthetic and biological communities due to emerging reports of their potential use as antitumour agents. The aim of this article is to highlight the most recent developments of this subset of the xanthone family by detailing the innate challenges of the construction of this class of natural products, new synthetic approaches, and pharmacological data.

Xantholipin B produced by the stnR inactivation mutant Streptomyces flocculus CGMCC 4.1223 WJN-1

“…17 In this work, we report an alternative XAN producer, S. flocculus CGMCC 4.1223 WJN-1, and isolated a new XAN analog, xantholipin B. Our results indicate that both compounds possess potent cytotoxicity against a wide range of human cancer cell lines, whereas xantholipin B exhibits greater cytotoxicity than XAN.…”

“…Several similar xanthone antibiotics have been reported, including lysolipin I, 10 albofungine, 11 actinoplanones, 12,13 cervinomycins [14][15][16] and LL-D42067α. 17 Polycyclic xanthone family members generally exhibit powerful antimicrobial and antitumor activities. XAN itself possesses potent cytotoxicity against the leukemia cell line HL-60 (IC 50 o0.3 μM) and the oral squamous carcinoma cell line KB (IC 50 o2 nM).…”

Enantioselective Halolactonization Reactions using BINOL-Derived Bifunctional Catalysts: Methodology, Diversification, and Applications

“…19 Collectively, compounds belonging to this class possess an array of potentially useful biological activities that include low nanomolar GI 50 ’s against a panel of human cancer cell lines as well as potent antibacterial and nematocidal properties. The promising biological activity of 65 coupled with its complex polycyclic architecture sparked considerable interest in the synthetic community, culminating in two successful enantioselective syntheses, (+)-kibdelone C completed by Porco, 20 and (−)-kibdelone C completed by Ready. 21 A key challenge for both groups was the synthesis of the chiral polyhydroxylated F ring (Scheme 3).…”

“…Toward this end, for his synthesis of (+)-kibdelone C, Porco utilized 66a , which was prepared in 13 steps and 15% overall yield. 20 Hudlicky subsequently reported an enzymatic approach that provided the related F ring precursor 66b in three steps, albeit in only 2.2% overall yield. 22 Ready’s approach to (−)-kibdelone C required the use of fragment 67 , which was in prepared in seven steps and 30% overall yield.…”

Total synthesis of Sparstolonin B, a potent anti-inflammatory agent

“…Xanthones [14][15][16][17][18] and isocoumarins [19][20][21][22] are key structural motifs in numerous important natural compounds with various biological activities and great attentions have been focused on the synthesis of their derivatives, but, to the best of our knowledge, the total synthesis of SsnB has not yet been achieved. Herein, we wish to report two routes for the rst total synthesis of SsnB.…”