Phenanthrenes: A Promising Group of Plant Secondary Metabolites

Abstract

Although phenanthrenes are considered to constitute a relatively small group of natural products, discovering new phenanthrene derivatives and evaluating their prospective biological activities have become of great interest to many research groups worldwide. Based on 160 references, this review covers the phytochemistry and pharmacology of 213 naturally occurring phenanthrenes that have been isolated between 2008 and 2016. More than 40% of the 450 currently known naturally occurring phenanthrenes were identified during this period. The family Orchidaceae is the most abundant source of these compounds, although several new plant families and genera have been involved in the search for phenanthrenes. The presence of certain substituent patterns may be restricted to specific families; vinyl-substituted phenanthrenes were reported only from Juncaceae plants, and prenylated derivatives occur mainly in Euphorbiaceae species. Therefore, these compounds also can serve as chemotaxonomic markers. Almost all of the newly isolated compounds have been studied for their biological activities (e.g., potential cytotoxic, antimicrobial, anti-inflammatory, and antioxidant effects), and many of them showed multiple activities. According to the accumulated data, denbinobin, with a novel mechanism of action, has great potential as a lead compound for the development of a new anticancer agent.

Cytotoxic Phenanthrene, Dihydrophenanthrene, and Dihydrostilbene Derivatives and Other Aromatic Compounds from Combretum laxum

“…Given the known antineoplastic potentialities of phenanthrene, dihydrophenanthrene and dihydrostilbenoid derivatives, particularly those obtained from members of the Combretaceae and Orchidaceae [ 7 , 39 , 40 ], compounds 1 - 6 were further assessed for their in vitro antiproliferative effects against five human neoplastic cell lines (except for 1 and 3 , which were tested against four cell lines due to insufficient material), based on the SRB (sulforhodamine B) assay and using cisplatin as a positive control.…”

“…The foregoing results also revealed that callosin ( 6 ), despite exhibiting the strongest DPPH-scavenging activity, was the least cytotoxic compound, indicating that, at least for the cell lines tested, antioxidant potential is unrelated to antiproliferative activity. Several phenanthrene and dihydrophenathrene derivatives are known for their DPPH scavenging properties [ 39 ]. However, literature data reveal that, as observed for compounds 2 – 6 , no relevant structure-activity relationships could clearly be established within these chemical classes, being postulated that the antioxidant capacity seemed to be related with the number of phenolic hydroxyl groups, either alone or together with methoxy groups, among other particular structural characteristics [ 45 , 48 , 49 ].…”

Phenanthrene Antibiotic Targets Bacterial Membranes and Kills Staphylococcus aureus With a Low Propensity for Resistance Development

“…Thousands of phytochemicals have been reported as antibacterial compounds and belong to different classes, such as alkaloids, terpenoids, polyphenols, tannins, and phenanthrenes. Among of them, phenanthrenes are a relatively uncommon class of aromatic metabolites in the plant kingdom, and are mainly found in the Orchidaceae and Juncaceae ( Kovács et al, 2008 ; Tóth et al, 2018 ). As typical phytoalexins of these plants, phenanthrenes have been shown to possess antimicrobial activities against various pathogens including drug-resistant strains ( Kovács et al, 2008 ; Tang et al, 2008 ; Yoshikawa et al, 2014 ; Qian et al, 2015 ; Tóth et al, 2018 ).…”

“…Among of them, phenanthrenes are a relatively uncommon class of aromatic metabolites in the plant kingdom, and are mainly found in the Orchidaceae and Juncaceae ( Kovács et al, 2008 ; Tóth et al, 2018 ). As typical phytoalexins of these plants, phenanthrenes have been shown to possess antimicrobial activities against various pathogens including drug-resistant strains ( Kovács et al, 2008 ; Tang et al, 2008 ; Yoshikawa et al, 2014 ; Qian et al, 2015 ; Tóth et al, 2018 ). Correspondingly, some phenanthrene-containing plants have been used in traditional medicine for the treatment of infectious diseases ( Sun et al, 2010 ; Namukobe et al, 2011 , 2014 ).…”

Antibacterial Activity of the Ethanolic Extracts Derived from Leaves and Pseudobulbs of Some Orchids Belonging to Coelogyne Genus Against Enterobacter Cloacae Strain

“…A wide range of phytochemicals has been reported as antibacterial compounds, belonging to different classes, such as alkaloids, terpenoids, polyphenols, tannins, and phenanthrenes. It was emphasized that among them, phenanthrenes are a relatively uncommon class of aromatic metabolites in the plant kingdom, which are mainly found in the Orchidaceae and Juncaceae (Kovács et al, 2008;Chen et al, 2018;Tóth et al, 2018).…”