Chemical Diversity and Biological Activities of Marine Sponges of the Genus Suberea: A Systematic Review.

Marine natural products (MNPs) continue to be in the spotlight in the global drug discovery endeavor. Currently, more than 30,000 structurally diverse secondary metabolites from marine sources have been isolated, making MNPs a profound, renewable source to investigate novel drug compounds. Marine sponges of the genus Suberea (family: Aplysinellidae) are recognized as producers of bromotyrosine derivatives, which are considered distinct chemotaxonomic markers for the marine sponges belonging to the order Verongida. This class of compounds exhibits structural diversity, ranging from simple monomeric molecules to more complex molecular scaffolds, displaying a myriad of biological and pharmacological potentialities. In this review, a comprehensive literature survey covering the period of 1998⁻2018, focusing on the chemistry and biological/pharmacological activities of marine natural products from marine sponges of the genus Suberea, with special attention to the biogenesis of the different skeletons of halogenated compounds, is presented.

Bioactive compounds from Retama raetam (Forssk.) Webb & Berthel. and their insecticidal activity against cotton pests Aphis gosspyii and Amrasca biguttula.

Cotton aphids, Aphis gosspyii and cotton jassids, Amrasca biguttula are destructive piercing sucking pests to many strategic crops, especially cotton, not only in Egypt but also all over the world. Using synthetic pesticides to control these pests led to several deleterious impacts. Natural pesticides can be used as a harmless alternative. Nine compounds were isolated from different fractions of Retama raetam using chromatographic techniques and identified by spectroscopic methods as eugenol (1), alpinumisoflavone (2), licoflavone C (3), ephedroidin (4), anagyrine (5), spartiene (6), genistein-8ß-C-glucoside (7), isoprunetin (8) and isoprunetin 7-O-ß-D-glucopyranoside (9). The methanol crude extract and its fractions (hexane, chloroform, ethyl acetate and butanol), as well as the isolated compounds were examined against A. gosspyii and A. biguttula as insecticides. The results showed that chloroform fraction was the most potent fraction against A. gosspyii and A. biguttula, with LC50 values of 65.66 and 64.43 ppm, respectively. As well, compounds 1, 5 and 6 were found to be more active, with LC50 values of 69.84, 25.49 and 27.22 ppm for A. gosspyii and 65.17, 24.07 and 24.78 ppm for A. biguttula, respectively. The most potent compounds (1, 5 and 6) exhibited AChE inhibition toward A. gosspyii compared with the control. So, it can be concluded that the isolated compounds eugenol 1, anagyrine 5 and spartiene 6 are the active principles due to their capability to inhibit AchE activity.

Sucrose esters of aryldihydronaphthalene-type lignans, and antitumor activity of extracts of Moltkiopsis ciliata (Forssk.) aerial parts.

One new compound (3f-[(7'R,8'R)-4,4'-dihydroxy-5-methoxy-2,7'-cycloligna-7-en-9-methoxycarbonyl, 9'-carbonyl-O-] -ß- D-fructofuranosyl- (2→1)-α- D-glucopyranoside) (Moltkiopsin A) (2) was isolated and identified from the extract of aerial parts of the wild Egyptian plant Moltkiopsis ciliata (Frossk.), family Boraginaceae, for the first time, along with two aryldihydronaphthalene lignans 3f→9':6f→9-[(7'R,8'R)-4,4'- dihydroxy-3,3',5-trimethoxy-2,7'-cycloligna-7-en-9,9'-dicarbonyl]-6g-acetyl-α-D-gluco pyranosyl-(1→2) -ß-D-fructofuranoside (Trigonotin A) (1) which was reported for the first time from this plant species and a known compound 3f→9':6f→9-[(7'R,8'R)-4,4'- dihydroxy-3,3',5-trimethoxy-2,7'-cycloligna-7-en-9,9'-dicarbonyl]-α-D-gluco pyranosyl - (1→2)- ß-D- fructofuranoside (Trigonotin C) (3). These compounds were separated and purified using different chromatographic techniques and their structures were elucidated by extensive 1D (1H and 13C NMR), and 2D NMR (COSY, HSQC, and HMBC), besides ESI-MS spectral methods. Extracts were screened as antioxidant, antitumor and antibacterial. The different extracts showed moderate to strong antioxidant capacities in DPPH assays. Ethyl acetate, methylene chloride and crude methanol extracts exhibited the most significant free radicals scavenging activity when compared to the standard antioxidant vitamin C. Hexane and butanol fractions showed the highest cytotoxicity against the cancer cell lines HepG2 and MCF-7.

The cardioprotective properties of Persicaria maculosa and Citrus sinensis extracts against doxorubicin-induced cardiotoxicity in mice.

Objective: This study assessed the cardioprotective properties of Persicaria maculosa (PME) and Citrus sinensis (CME) hydro-methanolic extracts, besides Citrus sinensis aqueous extract (CWE) against doxorubicin (DOX)-induced cardiotoxicity. Materials and Methods: The extracts were characterized. Mice were divided into eight groups: control (saline), DOX, protected (injected with 200 mg/kg of PME, CWE or CME for 21 days, orally, and DOX), and extracts (PME, CWE or CME administration, orally, for 21 days). DOX was injected (5 mg/kg, ip) on days 8, 13 and 18 of the experiment. Cardiac tumor necrosis factor-alpha (TNF-α), nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and carbonyl reductase 1 (CBR1) expression levels, besides superoxide dismutase, catalase, malondialdehyde, nitric oxide and total protein levels were evaluated. Serum lactate dehydrogenase, creatine phosphokinase cardiac isoenzyme, aspartate transaminase, cholesterol, triglycerides and creatinine levels, as well as the cardiac tissues were examined. Results: Comparing with the control, DOX considerably (p<0.01) up-regulated TNF-α expression, malondialdehyde, nitric oxide, cardiac enzymes, lipids and creatinine levels, while it significantly (p<0.01) down-regulated Nrf2 and CBR1. Additionally, DOX interfered with antioxidant enzymes' activities (p<0.01). Conversely, protected groups showed a significant (p<0.01) amelioration of DOX-induced cardiotoxic effects. Conclusion: The current study provides a new understanding of P. maculosa and C. sinensis cardioprotective mechanisms. The extracts' cardioprotective effects may be due to their antioxidant activities, ability to maintain the redox homeostasis through regulation of important antioxidant genes and primary antioxidant enzymes, and capability to recover inflammatory cytokines and lipids levels. Noteworthy, the tested extracts showed no toxic changes on the normal mice.

Quadrangulosides A-F: new pregnane glycosides from Caralluma quadrangula.

The phytochemical investigation of Caralluma quadrangula aerial parts yielded six new pregnane glycosides, quadrangulosides A-F (1-6), in addition to nine known pregnane glycosides and three known flavone glycosides. Structures of isolated phyto-constituents were elucidated via spectroscopic 1D-, 2D-NMR and spectrometric ESI-MS spectra.

Molluscicidal activity of Balanites aegyptiaca against Monacha cartusiana.

CONTEXT: Balanites aegyptiaca (L.) Delile (Zygophyllaceae) is a tropical tree that has many folk uses in various countries. The bark extract is used for the control of the fresh water snails that act as intermediary host of Schistosoma. OBJECTIVE: Study the molluscicidal activity and chemical constituents of seed oil and seed glycosides of B. aegyptiaca against Monacha cartusiana and determine the structure-activity relationship. MATERIALS AND METHODS: Two bioassay methods (residual film application and the leaf dipping technique) were used to evaluate the toxicity effect of the seed oil and glycosides, in concentrations of 1.000, 0.500, 0.250 and 0.125%. The seed oil was analysed by GC/MS. Acid hydrolysis and chromatographic separation were used to study the seed saponins. RESULTS: The bioassay of B. aegyptiaca against the land snail, M. cartusiana, indicated the activity of the seed oil and the high activity of the seed saponins. The seed glycosides gave 30.0, 53.3, 73.0 and 73.3% mortality for concentrations of 0.125, 0.250, 0.500 and 1.00%, respectively. The LC(50) values were 0.335 and 0.256%, respectively. The seed oil was analysed by GC/MS. Acid hydrolysis of the seed saponins gave a mixture of diosgenin, yamogenin and 3,5-spirostadiene. DISCUSSION AND CONCLUSION: To study the structure-activity relationship, a triterpenoidal saponin and a triterpenoidal saponins rich extract (of Zygophyllum coccenum) were proven to be inactive. Thus, the activity is associated with the steroidal, not triterpenoidal saponins. Moreover, a spirostane aglycone without sugar moiety, was found to be inactive and attained the activity by glycosidation.

Antibacterial and antioxidant activities of a novel enol ether nor-sesquiterpene isolated from Myrtus nivellei Batt. & Trab.

Myrtus nivellei is a plant traditionally used to treat diseases including infection of microbial origin. Several M. nivellei Batt. & Trab. extracts (dichloromethane, methanol and ethanol/water) were screened for their activity against 36 microorganisms, including strains resistant to antibiotics. These extracts inhibited on average 15 bacteria strains with minimum inhibition concentrations (MICs) ranging from 0.07 to 1.20 mg/mL. Bioassay guided fractionation was carried out with bioautography on TLC plates using four pathogenic bacteria strains, and following chromatographies (CPC and HPLC) led to the isolation of two novel enol ether nor-cadinane sesquiterpenes from the dichloromethane extract. The major compound (1) showed a strong antibacterial activity. Minimal inhibition concentration and minimal bactericidal concentration (MBC) values were determined against four bacteria: Acinetobacter baumanii, Stenotrophomonas maltophilia, Yersinia pseudotuberculosis and Staphylococcus lugdunensis. The best activity was observed against Acinetobacter baumanii with a MIC value of 9.7 µg/mL. This novel compound was also very active against a Staphylococcus aureus strain resistant to amoxicillin (MIC 19.5 µg/mL). In addition, compound 1 showed a very high antioxidant activity with both DPPH and metal chelate methods.

Batzella, Crambe and Monanchora: Highly Prolific Marine Sponge Genera Yielding Compounds with Potential Applications for Cancer and Other Therapeutic Areas.

Pyrroloquinoline and guanidine-derived alkaloids present distinct groups of marine secondary metabolites with structural diversity that displayed potentialities in biological research. A considerable number of these molecular architectures had been recorded from marine sponges belonging to different marine genera, including Batzella, Crambe, Monanchora, Clathria, Ptilocaulis and New Caledonian starfishes Fromia monilis and Celerina heffernani. In this review, we aim to comprehensively cover the chemodiversity and the bioactivities landmarks centered around the chemical constituents exclusively isolated from these three marine genera including Batzella, Crambe and Monanchora over the period 1981-2017, paying a special attention to the polycyclic guanidinic compounds and their proposed biomimetic landmarks. It is concluded that these marine sponge genera represent a rich source of novel compounds with potential applications for cancer and other therapeutic areas.

Sucrose diester of aryldihydronaphthalene-type lignans from Echium angustifolium Mill. and their antitumor activity.

Four previously undescribed sucrose diester of aryldihydronaphthalene-type lignans, named echiumins A-D, were isolated from the butanol fraction of Echium angustifolium Mill, in addition to a known compound, trigonotin A, which is reported for the first time from the title plant. The structures of isolated compounds were elucidated using spectroscopic methods such as HRESIMS and 1D and 2D NMR spectroscopy. The isolated compounds displayed strong to weak antitumor activity against HepG2 and MCF7 cancer cell lines, with echiumins A and D showed the most potent activity.

Two new pregnane glycoside diesters from Caralluma russeliana.

Two new pregnane glycoside diesters, 1 and 2, in addition to two triterpenoids, 3 and 4, and two sterols, 5 and 6 were isolated and identified from Caralluma russeliana (family Asclepiadaceae). The new pregnane glycosides, 14ß-benzoyloxy-15ß-isovaleroyloxy-16α-hydroxypregn-20-on-3-O-[ß-D-3-O-methyl-6-deoxyoleandrosopyranosyl-(1 → 4)-ß-D-cymaropyranosyl-(1 → 4)-ß-D-cymaropyranoside] (1) and 14ß-isovaleroyloxy-15ß-benzoyloxy-16α-hydroxypregn-20-on-3-O-[ß-D-3-O-methyl-6-deoxyoleandrosopyranosyl-(1 → 4)-ß-D-cymaropyranosyl-(1 → 4)-ß-D-cymaropyranoside] (2), are different from those isolated previously from the same species in the sugar moiety, in being diester, in being 20-one and in being 5,6 saturated by hydrogen. The isolated compounds were identified on the basis of spectral data.

A novel podophyllotoxin lignan from Justicia heterocarpa.

Chromatographic separation of the extract of Justicia heterocarpa T. ANDERS. afforded, in addition to known fatty acids, terpenoids and steroids, a new podophyllotoxin lignan. Structures were elucidated by spectroscopic methods, and the structure of the new lignan was confirmed by single crystal X-ray diffraction studies, which have shown that there is a H-bonding stabilized dimer.