Litoarbolide A: an undescribed sesquiterpenoid from the Red Sea soft coral Litophyton arboreum with an in vitro anti-malarial activity evaluation

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

“…In the anticancer bioassays, sesquiterpene 5 displayed no cytotoxic activities against the cell lines A549, MCF-7, and HepG2 (all IC 50 > 100 µmol/mL). The co-existence of alismol (3) and alismoxide (5) as well as an undescribed sesquiterpene, litoarbolide A (7), and three known analogues 4α,7β,10αtrihydroxyguai-5-ene (8), leptocladol B (9), and nephthetetraol (10) (Figure 4) in another Egyptian Red Sea L. arboreum specimen from Neweba, was revealed by Ahmed et al's work [33]. Viewing from the perspective of their structures, litoarbolide A (7) was supposed to be the biosynthetic precursor to other sesquiterpenes, which could be generated via further post-translational modifications.…”

“…Ahmed et al also made an Egyptian collection of L. arboreum from Neweba. Chemical investigation of this sample led to isolation of previously reported 4α-methylated steroids 98, 99, and 103 [33] (Figure 29). Anti-malarial activities against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of P. falciparum, together with the cytotoxic effect against the Vero cell line, were evaluated for these three isolates.…”

“…Very recently, Ahmed et al [33] carried out chemical investigation of the Red Sea specimen L. arboreum, which was collected at Neweba, Egypt. The acyclic sesquiterpene (2E,6E)-3-isopropyl-6-methyl-10-oxoundeca-2,6-dienal (2) was found from this sample, which possessed a sec-germacrane nucleus (Figure 3).…”

“…A study on the chemical constituents of the Chinese soft coral L. nigrum yielded three new sesquiterpenes lineolemnenes A-C (31)(32)(33), which possessed the neolemnane carbon framework, together with the related known compound 4-acetoxy-2,8-neolemnadien-5-one (34) [14] (Figure 13). It might be worth pointing out that the absolute configuration of 34 was unambiguously determined to be 1S,4S,12S by X-ray diffraction analysis for the first time.…”

“…Chemical study of Egyptian Red Sea collection L. arboreum from Neweba afforded steroids 110, 111, 3β,7β-dihydroxy-24-methylenecholesterol (115), and chabrolosteroid I (116) [33] (Figure 30). Anti-malarial bioassays indicated that compound 115 displayed weak activity against chloroquine-resistant strain P. falciparum W2 with IC 50 of 4.0 mg/mL, but was inactive against chloroquine-sensitive strain P. falciparum D6 at the concentration of 4.76 mg/mL.…”