Bioactivity and molecular docking of lactones isolated from Centaurea pseudosinaica Czerep.

Two cytotoxic sesquiterpene lactones, 17-epichlorohyssopifolin A (1) and chlorjanerin (2), and a monoterpene lactone, loliolide (3) were isolated from Centaurea pseudosinaica. The cytotoxicity of the total extract and terpenoids 1-3 were evaluated against three human cancer cells (HepG2, PC-3, and HT-29), along with the human normal primary epidermal keratinocytes (HEKa) cells. With IC50 values ranging between 0.6 ± 0.04 and 5.0 ± 0.61 µg/mL against HepG2; 0.2 ± 0.01 and 11.9 ± 1.31 µg/mL against PC-3, and 0.04 ± 0.013 and 8.9 ± 0.97 µg/mL against HT-29, the total extract, and lactones 1-3 demonstrated cytotoxic effects. Compound 1 displayed the strongest impact on all cancer cells and a slightly safe effect on the normal cells HEKa. Compound 1 caused accumulation of HepG2 and HT-29 cells in G1 phase as displayed cell cycle analysis. On the other hand, the cell distributions were increased in the S phase in PC-3 cells. Furthermore, 1 caused apoptosis in PC-3 and HePG2 cells with 91.50%, and 79.72 %, respectively. A higher fraction of necrotic cells was observed in HT-29 cells amounting to 23.60%. These results suggested that the promising cytotoxicity exhibited by 1 is brought by the apoptosis induction in the cancer cells, which were evaluated. As the compounds showed antiproliferative effect against the HT-29 cells, the docking simulation was performed aiming at determining how they would interact with the EGFR enzyme, whose PDB: 4I23 is considered one of the two distinct wild types of EGFR enzymes. The antibacterial activity results revealed that 3 showed the most remarkable antibacterial effects, especially against the examined Gram-positive bacteria. The total extract exhibited potent activity against all examined bacteria. The total extract showed a potent antifungal effect against two Candida and two Aspergillus pathogens. The antioxidant activity revealed the potency of the total extract and 3 as antioxidant candidates. The obtained results refer to the importance of Centaurea pseudosinaica as a source of potent antiproliferative agents and the whole plant as an antipathogenic and antioxidant agent.

The pro-apoptotic activity of sinueracasbanone D isolated from Sinularia Leptoclados in hepatocellular carcinoma cells.

The soft-bodied corals of the genera Sarcophyton and Sinularia (Alcyoniidae) are known as a warehouse of casbane and cembranoid diterpenoids with remarkable antitumor effects. Two casbane-type diterpenoids (1, 2) along with four cembrane-type diterpenoids (3-6) were isolated from the diethyl ether soluble fraction of the organic extracts of the Red Sea soft corals Sinularia leptoclados and Sarcophyton glaucum, respectively. The antiproliferative activity of all isolated compounds (1-6) against three hepatocellular carcinoma cells, namely, Huh-7, SNU 499, and HepG2, along with the normal cells EA.hy 926, was evaluated. Sinueracabanone D (1) displayed a remarkable antiproliferative effect against the examined cancer cell lines, especially HepG2 cells with IC50 of 4.0 ± 0.37 µM. Cell cycle analysis indicated compound 1 caused the accumulation of HepG2 cells in the G2/M-phase. Further, compound 1 exhibited significant pro-apoptotic activities in HepG2 cells as evidenced by annexin V staining, enhanced mRNA expression of Bax, cytochrome C, and caspase 3, as well as inhibition of Bcl2 expression. Also, challenging HepG2 cells with sinueracabanone D (1) enhanced the active oxygen species generation and decreased mitochondrial membrane potential. In conclusion, compound 1 possesses potent antiproliferative activities against HepG2 cells. These antiproliferative activities are mediated, at least partly, by their ability to induce apoptosis, mitochondrial dysfunction, and oxidative stress.

Green Synthesis of TiO2 Nanoparticles Using Natural Marine Extracts for Antifouling Activity.

Titanium dioxide (TiO2) nanoparticles were synthesized via a novel eco-friendly green chemistry approach using marine natural extracts of two red algae (Bostrychia tenella and Laurencia obtusa), a green alga (Halimeda tuna), and a brown alga (Sargassum filipendula) along with a marine sponge sample identified as Carteriospongia foliascens. X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis, X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR) were employed to characterize the crystal structure, surface morphology, and optical properties of the synthesized nanoparticles. Each of the as-synthesized marine extract based TiO2 nanoparticles was individually incorporated as an antifouling agent to form a newly fabricated marine paint formulation. The newly prepared formulations were applied on unprimed steel panels. A comparative study with a commercial antifouling paint (Sipes Transocean Coatings Optima) was carried out. After 108 days of the coated steel panels' immersion in the Eastern Harbour seawater of Alexandria-Egypt, the prepared paints using B. tenella and C. foliascens extracts demonstrated an excellent antifouling performance toward fouling organisms by inhibiting their settlement and controlling their adhesion onto the immersed panels. In contrast, heavy fouling with barnacles was observed on the surface of the coated panel with the commercial paint. The physicochemical parameters of the seawater surrounding the immersed coated panels were estimated to investigate the influence of the fabricated paint formulations. Interestingly, no effects of the immersed coated panels on the physicochemical characteristics of the surrounding seawater were observed. Based on the obtained results and a comparison with commercially available antifouling products, the marine extract based TiO2 nanoparticle preparations of B. tenella and C. foliascens are promising candidates for eco-friendly antifouling agents. Based on the obtained results and a comparison with commercially available antifouling products, the marine extract based TiO2 nanoparticle preparations of B. tenella and C. foliascens are promising candidates for eco-friendly antifouling agents, which could be attributed to the small crystallite sizes of 22.86 and 8.3 nm, respectively, in addition to the incorporation of carbon in the crystal structure of the nanoparticles.

Cembranoids from the Red Sea soft coral Sarcophyton glaucum protect against indomethacin-induced gastric injury.

Soft corals and their secondary metabolites represent an exceptional source of potential drugs. In this regard, Sarcophyton glaucum-derived secondary metabolites were examined for their preventive activities against indomethacin-induced gastric ulcer. Extraction and chromatographic processing of a specimen of S. glaucum collected from the Red Sea waters of Jeddah city resulted in the isolation of eight metabolites including two furanone-based cembranoids (1 and 2), two known pyran-based cembranoids (3 and 4), a known aromadendrene derivative (5), a δ-lactone fatty acid derivative (6), and two known gorgostane-type sterols (7 and 8). Compounds 1 and 6 are new chemical structures, named Δ12(20)-sarcophine and sarcoglaucanoate, respectively. In an initial pilot experiment, compounds 1 and 2 showed significant protective activities against indomethacin-induced peptic ulcer in rats. These data were evidenced by their ability to ameliorate the elevated ulcer indices and prevent histopathological alterations observed in the untreated animals. Their effects were mediated by enhanced mucin as shown by Alcian blue and periodic acid-Schiff (PAS) staining of stomach sections. Compounds 1 and 2 exerted significant antioxidant properties as they prevent reduced glutathione (GSH) depletion, malondialdehyde (MDA) accumulation, and superoxide dismutase (SOD) exhaustion. Furthermore, immunohistochemical analyses indicated that both compounds inhibited the expression of interleukin-6 (IL-6) and tumor necrosis-α (TNF-α) as compared to indomethacin alone-treated animals. These actions were accompanied by significant enhancement of tumor growth factor-ß (TGF-ß) expression. In conclusion, two cembranoids exhibited protective activities against indomethacin-induced peptic ulcer. This is, at least partly, mediated by their pro-mucin, antioxidant, anti-inflammatory, and TGF-ß stimulating properties.

Monoterpene Indole Alkaloids from the Aerial Parts of Rhazya stricta Induce Cytotoxicity and Apoptosis in Human Adenocarcinoma Cells.

Chromatographic investigation of the aerial parts of the Rhazya stricta (Apocynaceae) resulted in the isolation of two new monoterpene indole alkaloids, 6-nor-antirhine-N1-methyl (1) and razyamide (2), along with six known compounds, eburenine (3), epi-rhazyaminine (4), rhazizine (5), 20-epi-sitsirikine (6), antirhine (7), and 16-epi-stemmadenine-N-oxide (8). The chemical structures were established by various spectroscopic experiments. Compounds 1-8 exhibited cytotoxic effects against three cancer cells with IC50 values ranging between 5.1 ± 0.10 and 93.2 ± 9.73 µM against MCF-7; 5.1 ± 0.28 and 290.2 ± 7.50 µM against HepG2, and 3.1 ± 0.17 and 55.7 ± 4.29 µM against HeLa cells. Compound 2 showed the most potent cytotoxic effect against all cancer cell lines (MCF-7, HepG2 and HeLa with IC50 values = 5.1 ± 0.10, 5.1 ± 0.28, and 3.1 ± 0.17 µM, respectively). Furthermore, compound 2 revealed a significant increase in the apoptotic cell population of MCF-7, HepG2, and HeLa cells, with 31.4 ± 0.2%, 29.2 ± 0.5%, and 34.9 ± 0.6%, respectively. Compound 2 decreased the percentage of the phagocytic pathway on HepG2 cells by 15.0 ± 0.1%. These findings can explain the antiproliferative effect of compound 2.

Optimization of Thymoquinone-Loaded Self-Nanoemulsion for Management of Indomethacin-Induced Ulcer.

To improve the water solubility of thymoquinone (TQ), a major constituent of Nigella sativa seed oil, a TQ-loaded self-nanoemulsifying drug delivery system (SNEDDS) was prepared. The SNEDDS formulation was optimized using almond oil (AO) (Oil; X1), tween 80 (surfactant; X2) and polyethylene glycol 200 (PEG 200) (cosurfactant; X3) compounds as independent variables. The results showed that the globule size ranged from 65 to 320 nm. In addition, a strong agreement was reached between the system estimation and the experimental values of globule size. To evaluate the gastroprotective effect of optimized TQ-loaded SNEDDS against indomethacin (Indo.)-induced gastric ulcers in comparison with non-emulsified TQ, the ulcer index and histopathological changes were estimated. Optimized TQ-loaded SNEDDS showed improved gastroprotective activity against Indo.-induced ulcers relative to the non-emulsified TQ. In addition, the gastroprotective index was improved by 2-fold in TQ-loaded SNEDDS as compared to non-emulsified TQ. This is attributed to the strong antioxidant and the cytoprotective activities of the TQ. These results demonstrate enhancement of the efficacy of TQ through the optimized SNEDDS.

Antiproliferative Isoprenoid Derivatives from the Red Sea Alcyonacean Xenia umbellata.

From the soft coral Xenia umbellata, seven isoprenoid derivatives were isolated, including a new xenicane diterpene, xeniolide O (5) and a new gorgostane derivative gorgst-3ß,5α,6ß,11α,20(S)-pentol-3-monoacetate (7), along with three known sesquiterpenes (1-3), a known diterpene (4), and a known steroid (6). The extensive analyses of the NMR, IR, and MS spectral data led to determination of their chemical structures. Compounds 1-7 displayed a cytotoxic effect against breast adenocarcinoma (MCF-7), hepatocellular carcinoma (HepG2), and cervix adenocarcinoma (HeLa), with IC50 values ranging between 1.5 ± 0.1-23.2 ± 1.5; 1.8 ± 0.1-30.6 ± 1.1 and 0.9 ± 0.05-12.8 ± 0.5 µg/mL, respectively. Compound 3 showed potent cytotoxic effects against MCF-7, HepG2, and HeLa with IC50 values = 2.4 ± 0.20, 3.1 ± 0.10 and 0.9 ± 0.05 µg/mL, respectively. Compounds 2, 5, and 7 displayed cytotoxic effect against Hela cells with IC50 values = 12.8 ± 0.50, 6.7 ± 1.00 and 11.5 ± 2.20 µg/mL, respectively. Two DNA binding dyes, acridine orange (AO) and ethidium bromide (EtBr) were used for the detection of viable, apoptotic, and necrotic cells. The early apoptotic cell death was observed in all types of treated cells. The late apoptotic cells were highly present in HepG2 cells. Compounds 5 and 7 induced a high percentage of necrosis towards HepG2 and HeLa cells. The late apoptosis was recorded as a high rate after treatment with 7 on all cancer cells.

Legacy and emerging per- and polyfluorinated alkyl substances (PFASs) in sediment and edible fish from the Eastern Red Sea.

POLY: and perfluorinated alkyl substances (PFASs) are ubiquitously detected all around the world. Herein, for the first time, concentrations of 16 selected legacy and emerging PFASs are reported for sediment and edible fish collected from the Saudi Arabian Red Sea. Mean concentrations varied from 0.57 to 2.6 µg kg-1 dry weight (dw) in sediment, 3.89-7.63 µg kg-1 dw in fish muscle, and 17.9-58.5 µg kg-1 dw in fish liver. Wastewater treatment plant effluents represented the main source of these compounds and contributed to the exposure of PFAS to biota. Perfluorooctane sulfonate (PFOS) was the most abundant compound in sediment and fish tissues analysed, comprising between 42 and 99% of the ∑16PFAS. The short chain perfluorobutanoate (PFBA) was the second most dominant compound in sediment and was detected at a maximum concentration of 0.64 µg kg-1 dw. PFAS levels and patterns differed between tissues of investigated fish species. Across all fish species, ∑16PFAS concentrations in liver were significantly higher than in muscle by a factor ranging from 3 to 7 depending on fish species and size. The PFOS replacements fluorotelomer sulfonate (6:2 FTS) and perfluorobutane sulfonate (PFBS) exhibited a bioaccumulation potential in several fish species and 6:2 FTS, was detected at a maximum concentration of 7.1 ± 3.3 µg kg-1 dw in a doublespotted queenfish (Scomberoides lysan) liver. PFBS was detected at a maximum concentration of 2.65 µg kg-1 dw in strong spine silver-biddy (Gerres longirostris) liver. The calculated dietary intake of PFOS, perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) exceeded the safety threshold established by the European Food Safety Authority (EFSA) in 2020 in doublespotted queenfish muscle, indicating a potential health risk to humans consuming this fish in Jeddah, Saudi Arabia.

Euryops arabicus Promotes Healing of Excised Wounds in Rat Skin: Emphasis on Its Collagen-Enhancing, Antioxidant, and Anti-Inflammatory Activities.

Euryops arabicus Steud (E. arabicus) belongs to the family Asteraceae. It has several uses in folk medicine in the Arabian Peninsula. The current study aimed at evaluating the wound healing properties of the E. arabicus extract in rats. Primarily, E. arabicus successfully accelerated cell migration in vitro and it also showed no signs of dermal toxicity. Topical application of E. arabicus extract (5% or 20%) expedited healing of excised skin in rats. Histological examinations indicated that E. arabicus shortened epithelization period, stimulated fibroblast activity, and increased collagen deposition in wound tissues. The plant extract exerted antioxidant activity as evidenced by inhibition of GSH depletion and MDA accumulation and enhanced mRNA expression of Sod1 in wound tissues collected at the end of the experiment. Further, E. arabicus inhibited the rise of TNF-α and IL-1ß in the skin wound region. The anti-inflammatory was confirmed by the observed down regulation of Ptgs2, Nos2, IL-6, and NF-κB mRNA expression. In addition, the extract enhanced the expression of TGF-ß1 and HIF-1α in wounded skin tissues as indicated immunohistochemically. Conclusively, E. arabicus expedites excision wound healing in rats. Collagen-enhancing, anti-inflammatory, and antioxidant properties mediate the observed wound healing activity. These findings might contribute to our understanding of the ethnobotanical use of E. arabicus in wounds.

An Anti-Inflammatory 2,4-Cyclized-3,4-Secospongian Diterpenoid and Furanoterpene-Related Metabolites of a Marine Sponge Spongia sp. from the Red Sea.

Chemical investigation of a Red Sea Spongia sp. led to the isolation of four new compounds, i.e., 17-dehydroxysponalactone (1), a carboxylic acid, spongiafuranic acid A (2), one hydroxamic acid, spongiafuranohydroxamic acid A (3), and a furanyl trinorsesterpenoid 16-epi-irciformonin G (4), along with three known metabolites (-)-sponalisolide B (5), 18-nor- 3,17-dihydroxy-spongia-3,13(16),14-trien-2-one (6), and cholesta-7-ene-3ß,5α-diol-6-one (7). The biosynthetic pathway for the molecular skeleton of 1 and related compounds was postulated for the first time. Anti-inflammatory activity of these metabolites to inhibit superoxide anion generation and elastase release in N-formyl-methionyl-leucyl phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophil cells and cytotoxicity of these compounds toward three cancer cell lines and one human dermal fibroblast cell line were assayed. Compound 1 was found to significantly reduce the superoxide anion generation and elastase release at a concentration of 10 µM, and compound 5 was also found to display strong inhibitory activity against superoxide anion generation at the same concentration. Due to the noncytotoxic activity and the potent inhibitory effect toward the superoxide anion generation and elastase release, 1 and 5 can be considered to be promising anti-inflammatory agents.

Chemical Diversity and Bioactivities of Monoterpene Indole Alkaloids (MIAs) from Six Apocynaceae Genera.

By the end of the twentieth century, the interest in natural compounds as probable sources of drugs has declined and was replaced by other strategies such as molecular target-based drug discovery. However, in the recent times, natural compounds regained their position as extremely important source drug leads. Indole-containing compounds are under clinical use which includes vinblastine and vincristine (anticancer), atevirdine (anti-HIV), yohimbine (erectile dysfunction), reserpine (antihypertension), ajmalicine (vascular disorders), ajmaline (anti-arrhythmic), vincamine (vasodilator), etc. Monoterpene Indole Alkaloids (MIAs) deserve the curiosity and attention of researchers due to their chemical diversity and biological activities. These compounds were considered as an impending source of drug-lead. In this review 444 compounds, were identified from six genera belonging to the family Apocynaceae, will be discussed. These genera (Alstonia, Rauvolfia, Kopsia, Ervatamia, and Tabernaemontana, and Rhazya) consist of 400 members and represent 20% of Apocynaceae species. Only 30 (7.5%) species were investigated, whereas the rest are promising to be investigated. Eleven bioactivities, including antibacterial, antifungal, anti-inflammatory and immunosuppressant activities, were reported. Whereas cytotoxic effect represents 47% of the reported activities. Convincingly, the genera selected in this review are a wealthy source for future anticancer drug lead.

A new steroid glycoside from Begonia sp.: cytotoxic activity and docking studies.

Chemical investigation on the ethyl acetate extract of the aerial parts of Begonia sp. afforded a new steroid glycoside, 9(11)α,16(17)α-dioxirane-20,25-dihydroxy-ß-sitosterol-3-O-ß-glucopyranoside (1) along with a known steroidal glycoside, ß-sitosterol-3-O-ß-D-glucopyranoside (2). The Chemical structures were elucidated by 1D and 2D NMR and mass spectroscopic analysis. Cytotoxicity against four different cancer cell lines (HeLa, T47D, WiDr and Vero) was assessed. Compound 1 was more potent and selective against breast cancer cell line (T47D) than other cell lines with an IC50 value of 0.16 µg/mL. Further docking study of 1 exhibited the preference of molecule to bind in the epidermal growth factor receptor tyrosine kinase (EGFR-TK) binding pockets with docking scores of -97.8800 (PLANTS) and -3.56 kcal/mol (AutoDock 4.2.6).

Per- and polyfluoroalkyl substances (PFASs) in contaminated coastal marine waters of the Saudi Arabian Red Sea: a baseline study.

Per- and polyfluoroalkyl substances (PFASs) are today considered important constituents of the continuously growing substance group of persistent contaminants of emerging environmental concern (PCEC). Here, we report for the first time the concentrations of 12 relevant PFASs in 28 marine water samples from the Saudi Arabian coastal waters of the Red Sea. The sum levels of 12 PFASs (Σ12 PFAS) in surface seawater ranged from

Bioactivities of Lyngbyabellins from Cyanobacteria of Moorea and Okeania Genera.

Cyanobacteria are reported as rich sources of secondary metabolites that provide biological activities such as enzyme inhibition and cytotoxicity. Ten depsipeptide derivatives (lyngbyabellins) were isolated from a Malaysian Moorea bouillonii and a Red Sea Okeania sp.: lyngbyabellins G (1), O (2), P (3), H (4), A (7), 27-deoxylyngbyabellin A (5), and homohydroxydolabellin (6). This study indicated that lyngbyabellins displayed cytotoxicity, antimalarial, and antifouling activities. The isolated compounds were tested for cytotoxic effect against human breast cancer cells (MCF7), for antifouling activity against Amphibalanus amphitrite barnacle larvae, and for antiplasmodial effect towards Plasmodium falciparum. Lyngbyabellins A and G displayed potent antiplasmodial effect against Plasmodium, whereas homohydroxydolabellin showed moderate effect. For antifouling activity, the side chain decreases the activity slightly, but the essential feature is the acyclic structure. As previously reported, the acyclic lyngbyabellins are less cytotoxic than the corresponding cyclic ones, and the side chain increases cytotoxicity. This study revealed that lyngbyabellins, despite being cytotoxic agents as previously reported, also exhibit antimalarial and antifouling activities. The unique chemical structures and functionalities of lyngbyabellin play an essential role in their biological activities.

Marine-Derived Macrocyclic Alkaloids (MDMAs): Chemical and Biological Diversity.

The curiosity and attention that researchers have devoted to alkaloids are due to their bioactivities, structural diversity, and intriguing chemistry. Marine-derived macrocyclic alkaloids (MDMAs) are considered to be a potential source of drugs. Trabectedin, a tetrahydroisoquinoline derivative, has been approved for the treatment of metastatic soft tissue sarcoma and ovarian cancers. MDMAs displayed potent activities that enabled them to be used as anticancer, anti-invasion, antimalarial, antiplasmodial, and antimicrobial. This review presents the reported chemical structures, biological activities, and structure-activity relationships of macrocyclic alkaloids from marine organisms that have been published since their discovery until May 2020. This includes 204 compounds that are categorized under eight subclasses: pyrroles, quinolines, bis-quinolizidines, bis-1-oxaquinolizidines, 3-alkylpiperidines, manzamines, 3-alkyl pyridinium salts, and motuporamines.

Gene Expression Profiling to Delineate the Anticancer Potential of a New Alkaloid Isopicrinine From Rhazya stricta.

Background:Rhazya stricta has been used as a folkloric medicinal herb for treating various diseases such as diabetes, inflammatory disorders, and sore throat. Several studies have revealed the potential of this plant as an important source of phytochemicals with anticancer properties. Objective: The present study was designed to isolate a novel anticancer compound from Rhazya stricta and elucidate its mechanism of action using genomics approach. Methods:Rhazya stricta leaves extract was prepared, and several alkaloids were purified and characterized. These alkaloids were screened for their anticancer potential. One of the alkaloids, termed as isopicrinine, showed efficient cytotoxicity against MCF7 breast cancer cell line and was selected for further analysis. RNA-Seq transcription profiling was conducted to identify the affected genes and cellular pathways in MCF7 cells after treatment with isopicrinine alkaloid. Results: In vitro studies revealed that newly identified isopicrinine alkaloid possess efficient anticancer activity. Exposure of MCF7 cells with isopicrinine affected the expression of various genes involved in p53 signaling pathway. One of the crucial proapoptotic genes, significantly upregulated in MCF7 after exposure to alkaloid, was PUMA (p53 upregulated modulator of apoptosis), which is involved in p53-dependent and -independent apoptosis. Moreover, exposure of sublethal dose of isopicrinine alkaloid in breast cancer cell line led to the downregulation of survivin, which is involved in negative regulation of apoptosis. Besides, several genes involved in mitosis and cell proliferation were significantly downregulated. Conclusion: In this article, we report the determination of a new alkaloid isopicrinine from the aerial parts of Rhazya stricta with anticancer property. This compound has the potential to be developed as a drug for curing cancer.

Detection of PPCPs in marine organisms from contaminated coastal waters of the Saudi Red Sea.

The occurrence of PPCPs in macroalgae, barnacle and fish samples from contaminated coastal waters of the Saudi Red Sea is reported. Solvent extraction followed by solid phase extraction was applied to isolate the compounds, and their quantification was carried out by high performance liquid chromatography-tandem mass spectrometry. Atenolol, ranitidine, chlorpheniramine, DEET, and atrazine were detected in one or more macroalgae at

Serinolamides and Lyngbyabellins from an Okeania sp. Cyanobacterium Collected from the Red Sea.

NMR- and MS-guided fractionation of an extract of an Okeania sp. marine cyanobacterium, collected from the Red Sea, led to the isolation of four new metabolites, including serinolamides C (1) and D (2) and lyngbyabellins O (3) and P (4), together with the three known substances lyngbyabellins F (5) and G (6) and dolastatin 16 (7). The planar structures of the new compounds were determined using NMR and MS analyses. The absolute configurations of 1 and 2 were determined by Marfey's analysis of their hydrolysates. The absolute configuration of 3 was ascertained by chiral-phase chromatography of degradation products, while that of 4 was determined by comparison to 3 and 5. The cytotoxic and antifouling activities of these compounds were evaluated using MCF7 breast cancer cells and Amphibalanus amphitrite larvae, respectively. Compounds 3, 4, and 7 exhibited strong antifouling activity, and 3 and 7 were not cytotoxic. A structure-activity relationship was observed for the cytotoxicity of the lyngbyabellins with the presence of a side chain (4 is more active than 3) leading to greater activity. For the antifouling activity, the acyclic form without a side chain (3) was the most active.

Bio-active maneonenes and isomaneonene from the red alga Laurencia obtusa.

Three previously undescribed compounds, maneonenes and isomaneonene derivatives; in addition to five known compounds, two cuparene, one chamigrene, and two cis-maneonenes were isolated from the Red Sea red alga Laurencia obtusa. The chemical structures of all unknown metabolites were characterized employing spectroscopic methods and then were further confirmed by single crystal X-ray analysis. Jeddahenyne A has C-5-C-12 etheric linkage and C-13-C-14 carbon-carbon double bond; Jeddahenyne B has in addition to the aforementioned etheric linkage a C-13 carbonyl function and absence of halogenation, unusual features for the maneonenes while 12-debromo-12-methoxy isomaneonene A shows unrecorded methoxylation at C-12. The apoptosis-inducing or inhibiting effect of both compounds on apoptosis of peripheral blood neutrophils was studied.

Antiproliferative effects of selected marine organisms collected from Red Sea.

Ten selected marine organisms representing different classes of marine fauna and flora were collected from Saudi Arabia territorial water. They were Antipathes dichotoma, Rumphella sp., Dictoyota dichotoma, Hyrtios erectus, Petrosia sp., Heteroxenia fuscescens, Rumphella aggregata, Sinularia polydactyla, Sarcophyton glaucum, Sarcophyton trocheliophorum. Samples were lyophilized and extracted. Their cytotoxic activity was assessed by determining their IC50's against HepG2, A549 and PC-3 cancer cell lines. The extracts showed variable activities against A549 with IC50 in the range 388.3-0.1µg/mL; HepG2 with IC50 in range 382.5-0.1µg/ml and PC-3 with IC50 in the range 428.6-0.1µg/mL. Dictoyota dichotoma, Hyrtios erectus, Rumphella aggregata and Sarcophyton glaucum exhibited the highest antiproliferative activity. Therefore, their impact on cell cycle was examined by flow cytometry technique. It was concluded that they cause G0/G1, S-phase and G2/M cell cycle arrest.