Genus Litophyton: A Hidden Treasure Trove of Structurally Unique and Diversely Bioactive Secondary Metabolites

Abstract

Marine soft corals are prolific sources of various natural products that have served as a wealthy reservoir of diverse chemical scaffolds with potential as new drug leads. The genus Litophyton contains almost 100 species but only a small proportion of them has been chemically investigated, which calls for more attentions from global researchers. In the current work, 175 secondary metabolites have been discussed, drawing from published data spanning almost five decades, up to July 2023. The studied species of the genus Litophyton resided in various tropical and temperate regions and encompassed a broad range of biologically active natural products including terpenes, steroids, nitrogen-containing metabolites, lipids, and other metabolites. A wide spectrum of pharmacological effects of these compounds had been evaluated, such as cytotoxic, antiviral, antibacterial, antifungal, anti-malarial, antifeedant, anti-inflammatory, molluscicidal, PTP1B inhibitory, insect growth inhibitory, and neuroprotective activities. This review aims to offer an up-to-date survey of the literature and provide a comprehensive understanding of the chemical structures, taxonomical distributions, and biological activities of the reported metabolites from the title genus whenever available.

Keywords: Litophyton; bioactivities; cytotoxicity; secondary metabolites; soft coral; terpenes.

Figure 1

Carbon frameworks of the sesquiterpenes reported from soft corals of the genus Litophyton.

Figure 2

Chemical structure of the bicyclogermacrane sesquiterpene isolated from soft corals of the genus Litophyton.

Figure 3

Chemical structure of the sec-germacrane sesquiterpene from soft corals of the genus Litophyton.

Figure 4

Chemical structures of the guaiane sesquiterpenes from soft corals of the genus Litophyton.

Figure 5

Chemical structures of the pseudoguaiane sesquiterpenes from soft corals of the genus Litophyton.

Figure 6

Chemical structure of the himachalene sesquiterpene from soft corals of the genus Litophyton.

Figure 7

Chemical structure of the eudesmane sesquiterpene from soft corals of the genus Litophyton.

Figure 8

Chemical structure of the seco-eudesmane sesquiterpene from soft corals of the genus Litophyton.

Figure 9

Chemical structures of the tri-nor-eudesmane sesquiterpenes from soft corals of the genus Litophyton.

Figure 10

Chemical structure of the eremophilane sesquiterpene from soft corals of the genus Litophyton.

Figure 11

Chemical structures of the nardosinane sesquiterpenes from soft corals of the genus Litophyton.

Figure 12

Chemical structure of the nornardosinane sesquiterpene from soft corals of the genus Litophyton.

Figure 13

Chemical structures of the neolemnane sesquiterpenes from soft corals of the genus Litophyton.

Figure 14

Chemical structure of the seconeolemnane sesquiterpene from soft corals of the genus Litophyton.

Figure 15

Chemical structure of the kelsoane sesquiterpene from soft corals of the genus Litophyton.

Figure 16

Carbon frameworks of the bis-sesquiterpenes from soft corals of the genus Litophyton.

Figure 17

Chemical structure of the kelsoane-type bis-sesquiterpene from soft corals of the genus Litophyton.

Figure 18

Chemical structure of the eremophilane-nardosinane bis-sesquiterpene from soft corals of the genus Litophyton.

Figure 19

Carbon frameworks of the diterpenes reported from soft corals of the genus Litophyton.

Figure 20

Chemical structures of the cembrane diterpenes from soft corals of the genus Litophyton.

Figure 21

Chemical structures of the eunicellane diterpenes from soft corals of the genus Litophyton.

Figure 22

Chemical structures of the serrulatane diterpenes from soft corals of the genus Litophyton.

Figure 23

Chemical structures of the 5,9-cyclized serrulatane diterpenes from soft corals of the genus Litophyton.

Figure 24

Chemical structure of the chabrolane diterpene from soft corals of the genus Litophyton.

Figure 25

Chemical structure of the prenylbicyclogermacrane diterpene from soft corals of the genus Litophyton.

Figure 26

Chemical structure of the norditerpene from soft corals of the genus Litophyton.

Figure 27

Chemical structure of the tetraterpene from soft corals of the genus Litophyton.

Figure 28

Chemical structures of the meroterpenes from soft corals of the genus Litophyton.

Figure 29

Chemical structures of the 4α-methylated steroids from soft corals of the genus Litophyton.

Figure 30

Chemical structures of the ergostane-type and related steroids from soft corals of the genus Litophyton.

Figure 31

Chemical structures of the cholestane-type and related steroids from soft corals of the genus Litophyton.

Figure 32

Chemical structures of the pregnane-type and related steroids from soft corals of the genus Litophyton.

Figure 33

Chemical structures of the ceramides from soft corals of the genus Litophyton.

Figure 34

Chemical structures of the pyrimidines from soft corals of the genus Litophyton.

Figure 35

Chemical structures of the peptides from soft corals of the genus Litophyton.

Figure 36

Chemical structure of the prostaglandin from soft corals of the genus Litophyton.

Figure 37

Chemical structures of the γ-lactones from soft corals of the genus Litophyton.

Figure 38

Chemical structures of the fatty acids from soft corals of the genus Litophyton.

Figure 39

Chemical structures of the glycerol ethers from soft corals of the genus Litophyton.

Figure 40

Chemical structure of the selenide from soft corals of the genus Litophyton.

Figure 41

The distribution of the investigated species of the genus Litophyton.

Figure 42

Chemical profile of secondary metabolites from soft corals of the genus Litophyton.

Figure 43

Number of compounds reported from different species of the genus Litophyton.