Isopropyl(ene)-type Cembrane Diterpene an Important Chemotaxonomical Marker in Bornean Soft Coral Genus Sarcophyton

Two cembrane diterpenoids; (+)-11,12-epoxysarcophytol A (1) and sarcophytol W (2) were isolated from Sarcophyton sp. collected from Mantanani Island, Sabah. Secondary metabolites structures were elucidated based on spectroscopic data. This is the first record of cembranoid diterpenes isolated from the Bornean soft coral genus Sarcophyton. The isopropyl(ene)-type cembrane derivatives could be suggested as chemotaxonomical markers for soft coral genus Sarcophyton

Neoiriepentaol and nangenyne, halogenated diterpenoid and C15-acetogenin from red alga Laurencia nangii Masuda collected in Borneo [2018]

The red algal genus Laurencia is a prolific producer of halogenated secondary metabolites. A new tricyclic dibrominated diterpenoid, neoiriepentaol (1) and chlorinated C₁₅-acetogenin, nangenyne (2), along with two known terpenoids, neoirietetraol (3) and dactyloxene A (4), were isolated from methanol crude extract of red alga Laurencia nangii. The structures were established based on one- and two-dimensional nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR), and high-resolution electrospray ionization mass spectrometry (HRESIMS) data. These compounds were screened against seven species of marine fungi. Compounds 1–3 exhibited activity against Lagenidium thermophilum and Haliphthoros sabahensis. Potent activity was showed by 1 with L. thermophilum hyphal inhibition at MIC value of 12.5 μg mL⁻¹ and hyphal motility was observed at 50 μg mL⁻¹ within 24 h

Nangallenes A and B, halogenated nonterpenoid C15-acetogenins from the Bornean red alga Laurencia nangii

Two new halogenated nonterpenoids C15-acetogenins, nangallenes A-B (1–2), together with two known halogenated compounds itomanallene A (3) and 2,10-dibromo -3-chloro-α- chamigrene (4), were isolated and identified from the organic extract of the marine red alga Laurencia nangii Masuda collected from the coastal waters in Semporna, Borneo. Their structures were established by means of spectroscopic analysis including IR, high-resolution electrospray ionization mass spectrometry (HRESI-MS), and 1D and 2D NMR techniques. All these metabolites were submitted for the antifungal assay against four species of selected marine fungi. Compounds 1–4 showed potent activity against Haliphthoros sabahensis and Lagenidium thermophilum

Two new epimers of C15-acetogenin, 4-epi-isolaurallene and 4-epi-itomanallene A as diastereomeric model

Two new C15-acetogenins, 4-epi-isolaurallene (1) and 4-epi-itomanallene A (2) were isolated from a population of marine red alga Laurencia nangii Masuda from Carrington Reef. The structures of these compounds were determined intensively by NMR and HRESIMS data. Their configurations were elucidated by detailed comparison of chemical shifts, germinal protons splitting and NOE correlations with known and synthesized analogues. In addition, antibacterial activities of these compounds were evaluated. These compounds would serve as diastereomeric models for future reference. Since the isolaurallene, neolaurallene, 9-acetoxy-1,10,12-tribromo-4,7:6,13-bisepoxypentadeca-1,2-diene, itomanallene A and laurendecumallene A were isolated, compounds 1 and 2 were the sixth example of C15-acetogenin with dioxabicyclo[7.3.0]dodecene skeleton

New cembrane-type diterpenoids from Bornean soft coral N ephthea sp. with antifungal activity against Lagenidium thermophilum

Three new cembrane diterpenes, nephthecrassocolides A-B (1–2) and 6-acetoxy nephthenol acetate (3) along with three known compounds, 6-acetoxy-7,8-epoxy nephthenol acetate (4), epoxy nephthenol acetate (5) and nephthenol (6) were isolated from one population of Nephthea sp. Their structures were elucidated based on spectroscopic data analysis and the antifungal activities of compounds 1–6 were evaluated

A new bioactive cembranoid sarcophytonolide V from Bornean soft coral genus Sarcophyton

A new cembranolide diterpene, sarcophytonolide V (1), along with 6 known compounds, isosarcophytonolide D (2), (4Z,8S*,9R*,12E,14E) -9-hydroxy-1- (prop-1-en-2-yl) -8,12- dimethyl- oxabicyclo[9.3.2]-hexadeca-4,12,14-trien-18-one (3), (7E,11E)-3,4-epoxy-7,11, 15- cembratriene (4), (1S*,3S*,4S*,7E,11E)-3,4-epoxy-13-oxo-7,11,15-cembratriene (5), (-) -eunicenone (6), and 2-[(E,E,E)-7′, 8′-epoxy-4′,8′,12′ -trimethylcyclotetradeca- 1′,3′,11′- trienyl] propan-2-ol (7) were isolated from the Bornean soft coral Sarcophyton sp. Their structures were elucidated based on spectroscopic data, such as nuclear magnetic resonance (NMR) and high resolution electron spray ionization mass spectroscopy (HRESIMS). These compounds were evaluated for their biological activity against marine pathogenic fungi

Cytotoxicity and antibacterial poteltial of haligenated chamigrenes from Malaysian red algae, Laurencia majuscula

Red algae of the genus Laurencia have been known to produce a wide array of bioactive secondary metabolites. Here, we report the isolation of two new halogenated chamigrenes, lauremantanones A (1) and B (2), along with seven known compounds, dendroidiol (3), (+)-elatol (4), cartilagineol (5), obtusol (6), (+)-laurencenone B (7), 2-chloro-3-hydroxy- α-chamigren-9- one (8), and puertitol A (9), from a population of Laurencia majuscula (Harvey) Lucas from Mantanani Island (North Borneo). The structures of the two new metabolites were determined based on spectroscopic data (IR, 1D and 2D NMR, and MS). Compounds isolated from this alga exhibited potent cytotoxic (HeLa, MCF-7, P-388) and antibacterial (against antibiotic-resistant clinical bacteria) activities. The major metabolite of this population has significant importance in the geographical distribution of this species globally

Capgermacrene C, a New Sesquiterpenoid from a Bornean Soft Coral, Capnella sp.

A new bicyclogermacrene, capgermacrene C (1), along with a known compound, 1,4-peroxy-5-muurolene (2), were isolated from a population of Bornean soft coral Capnella sp. The structures of these metabolites were determined by extensive spectroscopic analysis, including NMR, and HRESIMS. Both compounds were subjected to antibacterial activity tests against antibiotic resistant clinical bacteria, but produced only negligible inhibition

Chabrolene, a Novel Norditerpene from the Bornean Soft Coral Nephthea sp.

Soft corals are often the research interest organism due to their structural diverse secondary metabolites with wide spectrum of biological activities range from antibacterial to anticancer potentials. The Borneo Island is rich in diversity of marine organisms including soft coral. Therefore, a population of Bornean soft coral belongs to genus Nephthea was collected from Mantanani Island (Sabah, Malaysia) which led to the isolation of a novel norditerpene, chabrolene (1) together with three known compounds (2-4). The chemical structure of 1 was determined by NMR and HREIMS data. Compound 1 exhibited repellent activity against the maize weevil Sitophilus zeamais

Cytotoxic Sesterterpenoids from Bornean Sponge Spongia sp.

Four scalarane sesterterpenoids, scalarolide acetate (1), scalarolide (2), 12-O-deacetyl-12 -epi-19-O-methylscalarin (3) and methyl 18- hydroxy- 19-norscalar-16 -en-20- carboxylate (4) were isolated from the Bornean sponge Spongia sp. The distinction between 12α-OAc and 12β-OAc, and 19-olide and 20-olide in sesterterpenes were revealed as well as previously not assigned relative configuration at 18-OH of 4 is reported herein for the first time. In addition, compounds 1-3 showed strong cytotoxic activities against adult T-cell leukemia (ATL), S1T cells. This is the first record of scalarane sesterterpenes from the Bornean sponge