Secondary Metabolites with Anti-Inflammatory Activity from Laurencia majuscula Collected in the Red Sea

Abstract

The chemical investigation of the organic extract of the red alga Laurencia majuscula collected from Hurghada reef in the Red Sea resulted in the isolation of five C15 acetogenins, including four tricyclic ones of the maneonene type (1–4) and a 5-membered one (5), 15 sesquiterpenes, including seven lauranes (6–12), one cuparane (13), one seco-laurane (14), one snyderane (15), two chamigranes (16, 17), two rearranged chamigranes (18, 19) and one aristolane (20), as well as a tricyclic diterpene (21) and a chlorinated fatty acid derivative (22). Among them, compounds 1–3, 5, 7, 8, 10, 11 and 14 are new natural products. The structures and the relative configurations of the isolated natural products have been established based on extensive analysis of their NMR and MS data, while the absolute configuration of maneonenes F (1) and G (2) was determined on the basis of single-crystal X-ray diffraction analysis. The anti-inflammatory activity of compounds 1, 2, 4–8, 10, 12–16, 18 and 20–22 was evaluated by measuring suppression of nitric oxide (NO) release in TLR4-activated RAW 264.7 macrophages in culture. All compounds, except 6, exhibited significant anti-inflammatory activity. Among them, metabolites 1, 4 and 18 did not exhibit any cytostatic activity at the tested concentrations. The most prominent anti-inflammatory activity, accompanied by absence of cytostatic activity at the same concentration, was exerted by compounds 5 and 18, with IC50 values of 3.69 μM and 3.55 μΜ, respectively.

A Survey of Recently Discovered Naturally Occurring Organohalogen Compounds

“…8 The widely distributed Laurencia nipponica has furnished two new metabolites, deacetylneonipponallene (10) and neopacifenol (11), along with several known organobromines, in a collection from the Kunashiri and Etorofu Islands. The new 10-hydroxyepiaplysinol (12) is found in Laurencia tristicha, 10 and a Sri Lankan specimen of Laurencia heteroclada yielded the new nonaromatic isolaurene analogue 13. 11 A collection of Laurencia majuscula from the Red Sea identified 22 metabolites including the halogenated maneonenes F−G (14− 16), 17, and 15-bromoisolaurene (18).…”

“…A collection of Laurencia majuscula from the Red Sea identified 22 metabolites including the halogenated maneonenes F–G ( 14 – 16 ), 17 , and 15-bromoisolaurene ( 18 ). Compound 17 is the most active in a standard anti-inflammatory activity assay (IC 50 3.69 μM) …”

“…Compound 17 is the most active in a standard anti-inflammatory activity assay (IC 50 3.69 μM). 12 Marine algae are also a major producer of natural bromophenols. A Red Sea collection of the green alga Avrainvillea amadelpha contains the new avrainvilleal ( 19) and 3-iodo-4-hydroxybenzaldehyde (20), together with 10 known metabolites.…”

Rugulopteryx-Derived Spatane, Secospatane, Prenylcubebane and Prenylkelsoane Diterpenoids as Inhibitors of Nitric Oxide Production

“…In this regard, structurally diverse natural products, mostly isolated from plants, have been reported to act by inhibiting NO production [35]. In recent years, several metabolites of macroalgae, including phenolic compounds [36][37][38], fucosterol [36], fucoxanthin [39], C 15 acetogenins [40], and terpenoids [40][41][42], have been described to decrease NO levels in LPS-stimulated macrophage RAW 264.7 cells and fucosterol also in microglial cells [43]. Together with our previous report [15], this study has demonstrated the NO inhibitory activity of algal diterpenoids of four structural classes in both immune cells Bv.2 and RAW 264.7 cells, showing the potential of macroalgal terpenoids in the search for lead compounds for new anti-inflammatory agents.…”

Approaches, Strategies and Procedures for Identifying Anti-Inflammatory Drug Lead Molecules from Natural Products

“…Several reviews have been written on NPs as sources of new drugs [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], yet no in-depth discussions of biodiscovery approaches and NP isolation and characterisation techniques have been reported previously. Hence, the current review aims to discuss the approaches used in selecting the starting materials, various extraction methods and modern techniques currently available for identifying anti-inflammatory small molecules from NP.…”