Sarcophyton glaucum is one of the most abundant and chemically studied soft corals with over 100 natural products reported in the literature, primarily cembrane diterpenoids. Yet, wide variation in the chemistry observed from S. glaucum over the past 50 years has led to its reputation as a capricious producer of bioactive metabolites. Recent molecular phylogenetic analysis revealed that S. glaucum is not a single species but a complex of at least seven genetically distinct species not distinguishable using traditional taxonomic criteria. We hypothesized that perceived intraspecific chemical variation observed in S. glaucum was actually due to differences between cryptic species (interspecific variation). To test this hypothesis, we collected Sarcophyton samples in Palau, performed molecular phylogenetic analysis, and prepared chemical profiles of sample extracts using gas chromatography-flame ionization detection. Both unsupervised (principal component analysis) and supervised (linear discriminant analysis) statistical analyses of these profiles revealed a strong relationship between cryptic species membership and chemical profiles. Liquid chromatography with tandem mass spectrometry-based analysis using feature-based molecular networking permitted identification of the chemical drivers of this difference between clades, including cembranoid diterpenes (2R,11R,12R)-isosarcophytoxide (5), (2S,11R,12R)-isosarcophytoxide (6), and isosarcophine (7). Our results suggest that early chemical studies of Sarcophyton may have unknowingly conflated different cryptic species of S. glaucum, leading to apparently idiosyncratic chemical variation.

Abstract. Analysis of BOD and COD has been done at estuary of Cut River in Alue Naga

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Polybrominated diphenyl ether (PBDE) compounds, derived from marine organisms, originate from symbiosis between marine sponges and cyanobacteria or bacteria. PBDEs have broad biological spectra; therefore, we analyzed structure and activity relationships of PBDEs to determine their potential as anticancer or antibacterial lead structures, through reactions and computational studies. Six known PBDEs (1–6) were isolated from the sponge, Lamellodysdiea herbacea; 13C NMR data for compound 6 are reported for the first time and their assignments are confirmed by their theoretical 13C NMR chemical shifts (RMSE <4.0 ppm). Methylation and acetylation of 1 (2, 3, 4, 5-tetrabromo-6-(3′, 5′-dibromo-2′-hydroxyphenoxy) phenol) at the phenol functional group gave seven molecules (7–13), of which 10, 12, and 13 were new. New crystal structures for 8 and 9 are also reported. Debromination carried out on 1 produced nine compounds (1, 2, 14, 16–18, 20, 23, and 26) of which 18 was new. Debromination product 16 showed a significant IC50 8.65 ± 1.11; 8.11 ± 1.43 µM against human embryonic kidney (HEK293T) cells. Compounds 1 and 16 exhibited antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae with MID 0.078 µg/disk. The number of four bromine atoms and two phenol functional groups are important for antibacterial activity (S. aureus and K. pneumoniae) and cytotoxicity (HEK293T). The result was supported by analysis of frontier molecular orbitals (FMOs). We also propose possible products of acetylation and debromination using analysis of FMOs and electrostatic charges and we confirm the experimental result.

Abstract. The collection of 337 specimens of the Chromodoris species was conducted in Sabang island, Indonesia, from 2013 to 2019. The purpose of this study to investigate the biodiversity and their secondary metabolites related by molecular structures. There are 21 species together with the chemical diversity detected by MS/MS molecular networking approach. The results showed that the nudibranch species of C. willani and C. geometrica have the highest abundance species, while C. aureopurpurea has the lowest abundance species. The result of the chemical investigation showed that the class of diterpene derivatives was found from all specimens of Chromodoris genus in Sabang island, the western part of the Indonesian Archipelago.Keywords: Nudibranch, biodiversity, chemical diversity, MS/MS molecular networking, Chromodoris genus

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Two new steroid sulfates 1 and 2 were obtained from a lipophilic extract of an undescribed species of a bryozoan in the genus Calyptotheca. The structures of compounds 1 and 2 were elucidated by spectroscopic methods and chemical modifications. Steroids 1 and 2 exhibited moderate cytotoxicity at IC 50 54 and 30 µM, respectively, against NBT-T2 cells.

The isolation and characterization of bioactive compounds of Indonesian's marine sponge Xestospongia sp. has been done. Bioactive secondary metabolites alkaloid was isolated based on bioassay guided-separation with several steps of chromatography and monitored by the inhibition of antibacterial test of Escherichia coli. V15B02 compound is identified as the alkaloid compounds at R f value of 0.7 using a mobile phase of methanol: water 9:1 (v/v). FTIR spectrum data interpretation results showed that the compound of V15B02 has hydroxyl groups with their O-H stretching vibration in the area around 3425.58 cm -1 and C-N vibration in the fingerprint region around 1111.00 cm -1 . Their sharp band with sharp and strong intensity on the number of 2924.09 cm -1 is an aliphatic C-H. That this was reinforced by a sharp uptake and up down in numbers of 1404.18 cm -1 which is C-H band indicates the terminal methyl groups. In the catchment area 1636.64 cm -1 showed the presence of C=O group. Indication of a cyclic amine group of alkaloids visible from the drop of vibration tertiary N in the area around 1165.00 cm -1 . V15B02 compounds have an activity inhibiting the growth of bacterial resistance Escherichia coli at a concentration of 70 ug/mL.