Marine cyanobacteria compounds with anticancer properties: a review on the implication of apoptosis

Okeanomitos corallinicola gen. and sp. nov. (Nostocales, Cyanobacteria), a new toxic marine heterocyte-forming Cyanobacterium from a coral reef

Cyanobacterial mats supplanting coral and spreading coral diseases in tropical reefs, intensified by environmental shifts caused by human-induced pressures, nutrient enrichment, and global climate change, pose grave risks to the survival of coral ecosystems. In this study, we characterized Okeanomitos corallinicola gen. and sp. nov., a newly discovered toxic marine heterocyte-forming cyanobacterium isolated from a coral reef ecosystem of the South China Sea. Phylogenetic analysis, based on the 16S rRNA gene and the secondary structure of the 16S-23S rRNA intergenic region, placed this species in a clade distinct from closely related genera, that is, Sphaerospermopsis stricto sensu, Raphidiopsis, and Amphiheterocytum. The O. corallinicola is a marine benthic species lacking gas vesicles, distinguishing it from other members of the Aphanizomenonaceae family. The genome of O. corallinicola is large and exhibits diverse functional capabilities, potentially contributing to the resilience and adaptability of coral reef ecosystems. In vitro assays revealed that O. corallinicola demonstrates notable cytotoxic activity against various cancer cell lines, suggesting its potential as a source of novel anticancer compounds. Furthermore, the identification of residual saxitoxin biosynthesis function in the genome of O. corallinicola, a marine cyanobacteria, supports the theory that saxitoxin genes in cyanobacteria and dinoflagellates may have been horizontally transferred between them or may have originated from a shared ancestor. Overall, the identification and characterization of O. corallinicola provides valuable contributions to cyanobacterial taxonomy, offering novel perspectives on complex interactions within coral reef ecosystems.

Bioactive substances of cyanobacteria and microalgae: Sources, metabolism, and anticancer mechanism insights

Cyanobacteria and microalgae contain various phytochemicals, including bioactive components in the form of secondary metabolites, namely flavonoids, phenolic acids, terpenoids, and tannins, with remarkable anticancer effects. This review highlights the recent advances in bioactive compounds, with potential anticancer activity, produced by cyanobacteria and microalgae. Previous in vitro investigations showed that many of these bioactive compounds exhibit potent effects against different human cancer types, such as leukemia and breast cancers. Multiple mechanisms implicated in the antitumor effect of these compounds were elucidated, including their ability to target cellular, subcellular, and molecular checkpoints linked to cancer development and promotion. Recent findings have highlighted various mechanisms of action of bioactive compounds produced by cyanobacteria and microalgae, including induction of autophagy and apoptosis, inhibition of telomerase and protein kinases, as well as modulation of epigenetic modifications. In vivo investigations have demonstrated a potent anti-angiogenesis effect on solid tumors, as well as a reduction in tumor volume. Some of these compounds were examined in clinical investigations for certain types of cancers, making them potent candidates/scaffolds for antitumor drug development.

Identification, Heterologous Expression, and Characterization of the Tolypodiol Biosynthetic Gene Cluster through an Integrated Approach

Cyanobacteria are tremendous producers of biologically active natural products, including the potent anti-inflammatory compound tolypodiol. However, linking biosynthetic gene clusters with compound production in cyanobacteria has lagged behind that in other bacterial genera. Tolypodiol is a meroterpenoid originally isolated from the cyanobacterium HT-58-2. Here we describe the identification of the tolypodiol biosynthetic gene cluster through heterologous expression in Anabaena and in vitro protein assays of a methyltransferase found in the tolypodiol biosynthetic gene cluster. We have also identified similar biosynthetic gene clusters in cyanobacterial and actinobacterial genomes, suggesting that meroterpenoids with structural similarity to the tolypodiols may be synthesized by other microbes. We also report the identification of two new analogs of tolypodiol that we have identified in both the original and heterologous producer. This work further illustrates the usefulness of Anabaena as a heterologous expression host for cyanobacterial compounds and how integrated approaches can help to link natural product compounds with their producing biosynthetic gene clusters.

Occurrence of aetokthonotoxin producer in natural samples - A PCR protocol for easy detection

Cyanobacteria are well known producers of bioactive metabolites, including harmful substances. The recently discovered "eagle killer" neurotoxin aetokthonotoxin (AETX) is produced by the epiphytic cyanobacterium Aetokthonos hydrillicola growing on invasive water thyme (Hydrilla verticillata). The biosynthetic gene cluster of AETX was previously identified from an Aetokthonos strain isolated from the J. Strom Thurmond Reservoir, Georgia, USA. Here, a PCR protocol for easy detection of AETX-producers in environmental samples of plant-cyanobacterium consortia was designed and tested. Three different loci of the AETX gene cluster were amplified to confirm the genetic potential for AETX production, along with two variable types of rRNA ITS regions to confirm the homogeneity of the producer´s taxonomic identity. In samples of Hydrilla from three Aetokthonos-positive reservoirs and one Aetokthonos-negative lake, the PCR of all four loci provided results congruent with the Aetokthonos presence/absence detected by light and fluorescence microscopy. The production of AETX in the Aetokthonos-positive samples was confirmed using LC-MS. Intriguingly, in J. Strom Thurmond Reservoir, recently Hydrilla free, an Aetokthonos-like cyanobacterium was found growing on American water-willow (Justicia americana). Those specimens were positive for all three aet markers but contained only minute amounts of AETX. The obtained genetic information (ITS rRNA sequence) and morphology of the novel Aetokthonos distinguished it from all the Hydrilla-hosted A. hydrillicola, likely at the species level. Our results suggest that the toxigenic Aetokthonos spp. can colonize a broader array of aquatic plants, however the level of accumulation of the toxin may be driven by host-specific interactions such as the locally hyper-accumulated bromide in Hydrilla.

Freshwater Cyanobacterial Toxins, Cyanopeptides and Neurodegenerative Diseases

Cyanobacteria produce a wide range of structurally diverse cyanotoxins and bioactive cyanopeptides in freshwater, marine, and terrestrial ecosystems. The health significance of these metabolites, which include genotoxic- and neurotoxic agents, is confirmed by continued associations between the occurrence of animal and human acute toxic events and, in the long term, by associations between cyanobacteria and neurodegenerative diseases. Major mechanisms related to the neurotoxicity of cyanobacteria compounds include (1) blocking of key proteins and channels; (2) inhibition of essential enzymes in mammalian cells such as protein phosphatases and phosphoprotein phosphatases as well as new molecular targets such as toll-like receptors 4 and 8. One of the widely discussed implicated mechanisms includes a misincorporation of cyanobacterial non-proteogenic amino acids. Recent research provides evidence that non-proteinogenic amino acid BMAA produced by cyanobacteria have multiple effects on translation process and bypasses the proof-reading ability of the aminoacyl-tRNA-synthetase. Aberrant proteins generated by non-canonical translation may be a factor in neuronal death and neurodegeneration. We hypothesize that the production of cyanopeptides and non-canonical amino acids is a more general mechanism, leading to mistranslation, affecting protein homeostasis, and targeting mitochondria in eukaryotic cells. It can be evolutionarily ancient and initially developed to control phytoplankton communities during algal blooms. Outcompeting gut symbiotic microorganisms may lead to dysbiosis, increased gut permeability, a shift in blood-brain-barrier functionality, and eventually, mitochondrial dysfunction in high-energy demanding neurons. A better understanding of the interaction between cyanopeptides metabolism and the nervous system will be crucial to target or to prevent neurodegenerative diseases.

Total Synthesis of Sanctolide A and Formal Synthesis of (2S)-Sanctolide A

Two synthetic strategies employing phosphate tether-mediated one-pot sequential protocols for the total synthesis of the polyketide nonribosomal peptide macrolide, sanctolide A, and the formal synthesis of the (2S)-epimer of sanctolide A are reported. In this work, a phosphate tether-mediated one-pot sequential ring-closing metathesis/cross metathesis/substrate-controlled "H2"/tether removal approach was developed to accomplish the total synthesis of the natural product sanctolide A.

Depsipeptides Targeting Tumor Cells: Milestones from In Vitro to Clinical Trials

Cancer is currently considered one of the most threatening diseases worldwide. Diet could be one of the factors that can be enhanced to comprehensively address a cancer patient's condition. Unfortunately, most molecules capable of targeting cancer cells are found in uncommon food sources. Among them, depsipeptides have emerged as one of the most reliable choices for cancer treatment. These cyclic amino acid oligomers, with one or more subunits replaced by a hydroxylated carboxylic acid resulting in one lactone bond in a core ring, have broadly proven their cancer-targeting efficacy, some even reaching clinical trials and being commercialized as "anticancer" drugs. This review aimed to describe these depsipeptides, their reported amino acid sequences, determined structure, and the specific mechanism by which they target tumor cells including apoptosis, oncosis, and elastase inhibition, among others. Furthermore, we have delved into state-of-the-art in vivo and clinical trials, current methods for purification and synthesis, and the recognized disadvantages of these molecules. The information collated in this review can help researchers decide whether these molecules should be incorporated into functional foods in the near future.

Phytotoxic, cytogenotoxic, and insecticidal activities of compounds from extracts of freshwater Lyngbya sp

The development of agroecology has promoted the discovery of new bioactive compounds that might act as biocides to control infections and microbial contamination. Algae belonging to Lyngbya genus produce several allelochemicals, which are compounds with crop protection potential. The present study aimed to examine primary and secondary compounds derived from Lyngbya sp. extracts (aqueous and hydroethanolic) on phytotoxic, cytogenotoxic, and insecticidal activities. Determination of compounds indicated the presence predominantly of proteins and flavonoids. The extracts presented physicochemical characteristics that produced (1) 89% germination inhibition using hydroethanolic extract and (2) diminished development of seedlings of L. sativa by hydroethanolic extract as evidenced by reduced radicles length in 83.54%. Aqueous and hydroethanolic Lyngbya sp. extracts significantly interfered with meristematic cells of A. cepa, as evidenced by chromosomal alterations and aberrant mitotic phases in cells. Extracts also exhibited pro-oxidative activity and a potent insecticidal potential on S. zeamais, indicating that the hydroethanolic extract produced 100% insect mortality at 75 mg/ml after 48 hr while the aqueous extract initiated 90% mortality at the same concentration after 82 hr. Therefore, data demonstrate that Lyngbya genus provides basic information for new environmental and ecotoxicological studies to seek a possible source of proteins and flavonoids to be used in agroecological management.

Anti-lung cancer properties of cyanobacterial bioactive compounds

Lung cancer, the most prevalent gender-independent tumor entity in both men and women, is among the leading cause of cancer-related deaths worldwide. Despite decades of effort in developing improved therapeutic strategies including immunotherapies and novel chemotherapeutic agents, only modest improvements in outcome and long-term survival of lung cancer patients have been achieved. Therefore, exploring new and exceptional sources for bioactive compounds that might serve as anti-cancer agents might be the key to improving lung cancer therapy. On account of diverse forms, cyanobacteria might serve as a potential source for compounds with potential therapeutic applicability against malignant disorders, including cancer. The assorted arrays of metabolic mechanisms synthesize a plethora of bioactive compounds with immense biological potential. These compounds have been proven to be effective against various cancer cell lines and xenograft animal models. The present review provides an overview of the most promising cyanobacteria-derived bioactive compounds proven to exhibit anti-cancer properties in in-vitro and in-vivo studies and highlights their applicability as potential therapeutic agents with a focus on their anti-lung cancer properties.

Marine Cyanobacteria as Sources of Lead Anticancer Compounds: A Review of Families of Metabolites with Cytotoxic, Antiproliferative, and Antineoplastic Effects

The marine environment is highly diverse, each living creature fighting to establish and proliferate. Among marine organisms, cyanobacteria are astounding secondary metabolite producers representing a wonderful source of biologically active molecules aimed to communicate, defend from predators, or compete. Studies on these molecules’ origins and activities have been systematic, although much is still to be discovered. Their broad chemical diversity results from integrating peptide and polyketide synthetases and synthases, along with cascades of biosynthetic transformations resulting in new chemical structures. Cyanobacteria are glycolipid, macrolide, peptide, and polyketide producers, and to date, hundreds of these molecules have been isolated and tested. Many of these compounds have demonstrated important bioactivities such as cytotoxicity, antineoplastic, and antiproliferative activity with potential pharmacological uses. Some are currently under clinical investigation. Additionally, conventional chemotherapeutic treatments include drugs with a well-known range of side effects, making anticancer drug research from new sources, such as marine cyanobacteria, necessary. This review is focused on the anticancer bioactivities of metabolites produced by marine cyanobacteria, emphasizing the identification of each variant of the metabolite family, their chemical structures, and the mechanisms of action underlying their biological and pharmacological activities.

Pseudanabaena galeata CCNP1313—Biological Activity and Peptides Production

Even cyanobacteria from ecosystems of low biodiversity, such as the Baltic Sea, can constitute a rich source of bioactive metabolites. Potent toxins, enzyme inhibitors, and anticancer and antifungal agents were detected in both bloom-forming species and less commonly occurring cyanobacteria. In previous work on the Baltic Pseudanabaena galeata CCNP1313, the induction of apoptosis in the breast cancer cell line MCF-7 was documented. Here, the activity of the strain was further explored using human dermal fibroblasts, African green monkey kidney, cancer cell lines (T47D, HCT-8, and A549ACE2/TMPRSS2) and viruses (SARS-CoV-2, HCoV-OC43, and WNV). In the tests, extracts, chromatographic fractions, and the main components of the P. galeata CCNP1313 fractions were used. The LC-MS/MS analyses of the tested samples led to the detection of forty-five peptides. For fourteen of the new peptides, putative structures were proposed based on MS/MS spectra. Although the complex samples (i.e., extracts and chromatographic fractions) showed potent cytotoxic and antiviral activities, the effects of the isolated compounds were minor. The study confirmed the significance of P. galeata CCNP1313 as a source of metabolites with potent activity. It also illustrated the difficulties in assigning the observed biological effects to specific metabolites, especially when they are produced in minute amounts.

Biological Activity and Stability of Aeruginosamides from Cyanobacteria

Aeruginosamides (AEGs) are classified as cyanobactins, ribosomally synthesized peptides with post-translational modifications. They have been identified in cyanobacteria of genera Microcystis, Oscillatoria, and Limnoraphis. In this work, the new data on the in vitro activities of three AEG variants, AEG A, AEG625 and AEG657, and their interactions with metabolic enzymes are reported. Two aeruginosamides, AEG625 and AEG657, decreased the viability of human breast cancer cell line T47D, but neither of the peptides was active against human liver cancer cell line Huh7. AEGs also did not change the expression of MIR92b-3p, but for AEG625, the induction of oxidative stress was observed. In the presence of a liver S9 fraction containing microsomal and cytosolic enzymes, AEG625 and AEG657 showed high stability. In the same assays, quick removal of AEG A was recorded. The peptides had mild activity against three cytochrome P450 enzymes, CYP2C9, CYP2D6 and CYP3A4, but only at the highest concentration used in the study (60 µM). The properties of AEGs, i.e., cytotoxic activity and in vitro interactions with important metabolic enzymes, form a good basis for further studies on their pharmacological potential.

Can be marine bioactive peptides (MBAs) lead the future of foodomics for human health?

Marine organisms are considered a cache of biologically active metabolites with pharmaceutical, functional, and nutraceutical properties. Among these, marine bioactive peptides (MBAs) present in diverse marine species (fish, sponges, cyanobacteria, fungi, ascidians, seaweeds, & mollusks) have acquired attention owing to their broad-spectrum health-promoting benefits. Nowadays, scientists are keener exploring marine bioactive peptides precisely due to their unique structural and biological properties. These MBAs have reported ameliorating potential against different diseases like hypertension, diabetes, obesity, HIV, cancer, oxidation, and inflammation. Furthermore, MBAs isolated from various marine organisms may also have a beneficial role in the cosmetic, nutraceutical, and food industries. Few marine peptides and their derivative are approved for commercial use, while many MBAs are in various pre-clinical and clinical trials. This review mainly focuses on the diversity of marine bioactive peptides in marine organisms and their production procedures, such as chemical and enzymatic hydrolysis. Moreover, MBAs' therapeutic and biological potential has also been critically discussed herein, along with their status in drug discovery, pre-clinical and clinical trials.

da Silva G, Silva ALFD, Lima LRAD, Bezerra RP, Marques DDAV. Bioactive Compounds of Arthrospira spp. (Spirulina) with Potential Anticancer Activities: A Systematic Review

Arthrospira, a genus of blue-green cyanobacteria, is known for its great biological activity due to the presence of a large number of substances that are potentially active against tumor cells. This review aimed to evaluate the potential of Arthrospira spp. for the treatment or reduction of several types of cancer, in addition to elucidating the mechanism of action by which their compounds act on tumor cells. A systematic review was carried out in PubMed, Science Direct, LILACS, and SciELO databases, including original studies from 2009 to 2020. A total of 1306 articles were independently assessed according to the eligibility criteria, of which 20 articles were selected and assessed for the risk of bias using seven criteria developed by the authors. Arthrospira spp. of cyanobacteria have been evaluated against eight different types of cancer, mainly colon cancer. Among all the compounds, phycocyanin was the most used, followed by peptides and photosensitizers. In general, compounds from Arthrospira spp. act as anticancer agents by inhibiting the proliferation of tumor cells, triggering cell cycle arrest, and inducing apoptosis via different signaling pathways. In addition, these compounds also exhibited antioxidant, antiangiogenic, and antimetastatic activities. Phycocyanin demonstrated better efficacy against several types of cancer via different activities and therapeutic targets. Furthermore, it was the only molecule that functioned in synergy with other drugs that are already well established for the treatment of cancer.

Cyanobacteria derived compounds: Emerging drugs for cancer management

The wide diversity of cyanobacterial species and their role in a variety of biological activities have been reported in the previous few years. Cyanobacteria, especially from marine sources, constitutes a major source of biologically active metabolites that have gained great attention especially due to their anticancer potential. Numerous chemically diverse metabolites from various cyanobacterial species have been recognized to inhibit the growth and progression of tumor cells through the induction of apoptosis in many different types of cancers. These metabolites activate the apoptosis in the cancer cells by different molecular mechanisms, however, the dysregulation of the mitochondrial pathway, death receptors signaling pathways, and the activation of several caspases are the crucial mechanisms that got considerable interest. The array of metabolites and the range of mechanisms involved may also help to overcome the resistance acquired by the different tumor types against the ongoing therapeutic agents. Therefore, the primary or secondary metabolites from the cyanobacteria as well as their synthetic derivates could be used to develop novel anticancer drugs alone or in combination with other chemotherapeutic agents. In this study, we have discussed the role of cyanobacterial metabolites in the induction of cytotoxicity and the potential to inhibit the growth of cancer cells through the induction of apoptosis, cell signaling alteration, oxidative damage, and mitochondrial dysfunctions. Moreover, the various metabolites produced by cyanobacteria have been summarized with their anticancer mechanisms. Furthermore, the ongoing trials and future developments for the therapeutic implications of these compounds in cancer therapy have been discussed.

Marine-derived pipeline anticancer natural products: a review of their pharmacotherapeutic potential and molecular mechanisms

Background

Cancer is a complex and most widespread disease and its prevalence is increasing worldwide, more in countries that are witnessing urbanization and rapid industrialization changes. Although tremendous progress has been made, the interest in targeting cancer has grown rapidly every year. This review underscores the importance of preventive and therapeutic strategies.

Main text

Natural products (NPs) from various sources including plants have always played a crucial role in cancer treatment. In this growing list, numerous unique secondary metabolites from marine sources have added and gaining attention and became potential players in drug discovery and development for various biomedical applications. Many NPs found in nature that normally contain both pharmacological and biological activity employed in pharmaceutical industry predominantly in anticancer pharmaceuticals because of their enormous range of structure entities with unique functional groups that attract and inspire for the creation of several new drug leads through synthetic chemistry. Although terrestrial medicinal plants have been the focus for the development of NPs, however, in the last three decades, marine origins that include invertebrates, plants, algae, and bacteria have unearthed numerous novel pharmaceutical compounds, generally referred as marine NPs and are evolving continuously as discipline in the molecular targeted drug discovery with the inclusion of advanced screening tools which revolutionized and became the component of antitumor modern research.

Conclusions

This comprehensive review summarizes some important and interesting pipeline marine NPs such as Salinosporamide A, Dolastatin derivatives, Aplidine/plitidepsin (Aplidin®) and Coibamide A, their anticancer properties and describes their mechanisms of action (MoA) with their efficacy and clinical potential as they have attracted interest for potential use in the treatment of various types of cancers.

Molecular detection of some toxogenic cyanobacteria in Tigris River in Baghdad-Iraq

Cyanobacteria and their pollution are being increasingly commonly reported worldwide that cause a serious hazard to environmental and human health. Cyanotoxin was the most algal toxin reported to be produced by several orders of cyanobacteria. This study aimed to provide a technique to detect cylindrosprmopsin and saxitoxin biosynthesis genes in the river. In November, December 2019, and January 2020. Cyanobacteria were isolated from freshwater of Tigris River and identified by compound microscope also conventional PCR. Five isolates of cyanobacteria that successfully amplified a gene fragment from the phycocyanin were found in all cyanobacteria (Microcystis flosaquae, Microcystis sp, anabaena circinalis, nostoc commune and westiellopsis prolifica) and all isolates successfully amplified aoaC gene to detecting the cylidrospemopsin and the saxitoxin. Our results concluded that PCR assay can be used for early detection of cylidrospemopsin and the saxitoxin producing cyanobacteria in river water that useful to stations responsible for the preparation of drinking water to public.

Cyanobacteria as Natural Therapeutics and Pharmaceutical Potential: Role in Antitumor Activity and as Nanovectors

Cyanobacteria (blue-green microalgae) are ubiquitous, Gram-negative photoautotrophic prokaryotes. They are considered as one of the most efficient sources of bioactive secondary metabolites. More than 50% of cyanobacteria are cultivated on commercial platforms to extract bioactive compounds, which have bene shown to possess anticancer activity. The chemically diverse natural compounds or their analogues induce cytotoxicity and potentially kill a variety of cancer cells via the induction of apoptosis, or altering the activation of cell signaling, involving especially the protein kinase-C family members, cell cycle arrest, mitochondrial dysfunctions and oxidative damage. These therapeutic properties enable their use in the pharma and healthcare sectors for the betterment of future generations. This review provides a baseline overview of the anti-cancerous cyanobacterial bioactive compounds, along with recently introduced nanomaterials that could be used for the development of new anticancer drugs to build a healthy future for mankind.

Marine Cyanobacteria and Microalgae Metabolites-A Rich Source of Potential Anticancer Drugs

Cancer is at present one of the utmost deadly diseases worldwide. Past efforts in cancer research have focused on natural medicinal products. Over the past decades, a great deal of initiatives was invested towards isolating and identifying new marine metabolites via pharmaceutical companies, and research institutions in general. Secondary marine metabolites are looked at as a favorable source of potentially new pharmaceutically active compounds, having a vast structural diversity and diverse biological activities; therefore, this is an astonishing source of potentially new anticancer therapy. This review contains an extensive critical discussion on the potential of marine microbial compounds and marine microalgae metabolites as anticancer drugs, highlighting their chemical structure and exploring the underlying mechanisms of action. Current limitation, challenges, and future research pathways were also presented.

A rapid and low-cost method for genomic DNA extraction from the cyanobacterium Synechocystis

A two-step method is reported for preparation of genomic DNA from the model cyanobacterium Synechocystis that can be performed with minimal equipment and reagents in about an hour. High yields of genetic material can be obtained (200-450 ng/μl) with reasonable purity. A further ethanol precipitation step can be included but is not necessary if template is simply required for polymerase chain reaction (PCR) or digestion. This new protocol is helpful for amplification of genes of interest in early-stage research projects and for low throughput screening of transformants. It is more reliable than colony PCR of Synechocystis cultures, and less involved and cheaper than existing clean-DNA preparation methods. It represents an unusually simple and reliable extraction protocol for the growing body of research making use of this cyanobacterium.

Marine Cyanobacteria: A Source of Lead Compounds and their Clinically-Relevant Molecular Targets

The prokaryotic filamentous marine cyanobacteria are photosynthetic microbes that are found in diverse marine habitats, ranging from epiphytic to endolithic communities. Their successful colonization in nature is largely attributed to genetic diversity as well as the production of ecologically important natural products. These cyanobacterial natural products are also a source of potential drug leads for the development of therapeutic agents used in the treatment of diseases, such as cancer, parasitic infections and inflammation. Major sources of these biomedically important natural compounds are found predominately from marine cyanobacterial orders Oscillatoriales, Nostocales, Chroococcales and Synechococcales. Moreover, technological advances in genomic and metabolomics approaches, such as mass spectrometry and NMR spectroscopy, revealed that marine cyanobacteria are a treasure trove of structurally unique natural products. The high potency of a number of natural products are due to their specific interference with validated drug targets, such as proteasomes, proteases, histone deacetylases, microtubules, actin filaments and membrane receptors/channels. In this review, the chemistry and biology of selected potent cyanobacterial compounds as well as their synthetic analogues are presented based on their molecular targets. These molecules are discussed to reflect current research trends in drug discovery from marine cyanobacterial natural products.

Assessment of the antioxidant and anticancer potential of different isolated strains of cyanobacteria and microalgae from soil and agriculture drain water

The potential usage of cyanobacteria and microalgae as a promising and alternative source for new and safe therapeutic compounds is recently caught the attention, due to its versatile properties as antitumor, antioxidant, antifungal, and antiviral agents. Primarily, the cyanobacteria and microalgae from fresh and marine water are previously studied, however those isolated from soil and agriculture drain water were poorly investigated. Therefore, this study aimed to screen and characterize the antioxidant profile, as well as the potential anticancer assessment of 12 species of cyanobacteria and two species of microalgae strains isolated from soil and agriculture drain water. The data showed that total phenol contents were highest in Anabaena oryzae and Aphanizomenon gracile (27.39 and 26.83 mg GAE/g, respectively), followed by Leptolyngbya fragilis (22.96 mg GAE/g). Out of the 14 species identified, the cyanobacterium Dolichospermum flos-aquae HSSASE2 exhibited the most elevated antioxidant activity in terms of NO scavenging activity and anti-lipid peroxidation potential (IC₅₀ = 28.7 ± 0.1 and 11.9 ± 0.2 μg/ml, respectively) and the lowest DPPH radical scavenging activity (467.7 μg/ml). Screening of the anticancer potential of all studied strains against four different human cancer cell lines (Caco-2, MCF-7, PC3, and HepG-2) demonstrated that Dolichospermum crassum HSSASE20 has the highest anticancer effect among all tested species against colon and prostate cancer cell lines (IC₅₀ = 57.9 ± 0.4 and 44.1 ± 0.2 μg/ml, respectively), while Oscillatoria sancta HSSASE19 recorded the most anticancer effect against MCF-7 (breast cancer) cell line (IC₅₀ = 15.1 ± 0.7 μg/ml). Dolichospermum spiroides HSSASE18 obtained the highest anticancer effect HepG-2 (hepatic cancer) cell line (IC₅₀ = 48.8 ± 0.7 μg/ml). Additionally, cytotoxicity against healthy peripheral blood mononuclear cells was studied and revealed that Oscillatoria sancta was the safest one among all studied strains. Data obtained from the sensitivity index demonstrated that Dolichospermum crassum was the most sensitive strain against the four cancerous cell lines. Cyanobacteria and microalgae from the soil and drain water sources are efficient free radical scavengers, containing apoptogens capable of stimulating apoptotic cascades and overcoming chemo-resistance in cancer therapy. Thus, these novel secondary metabolites are an excellent alternative, safe, and low-cost antioxidant and anticancer therapeutic compounds.

Can marine-derived fungus Neosartorya siamensis KUFA 0017 extract and its secondary metabolites enhance antitumor activity of doxorubicin? An in vitro survey unveils interactions against lung cancer cells

Doxorubicin (Dox) is one of the most successful anticancer drugs in use. However, chemoresistance is one of the main limitations that patients face. Therefore, development of new strategies to improve the efficacy of Dox is needed. Marine-derived fungi are especially promising sources of new anticancer compounds. In this work, antitumor activity of crude ethyl extract of the cultures of the marine-derived fungus Neosartorya siamensis KUFA 0017 (NS), combined with Dox, was evaluated in six cancer cell lines. To evaluate possible mechanisms involved in the eventual improvement of Dox's cytotoxicity by NS extract, effects on DNA damage, cell death, ultrastructural modifications, and intracellular accumulation of Dox were assessed. The NS extract demonstrated a significant enhancement of Dox's cytotoxic activity in A549 cells, inducing DNA damage, cell death, and intracellular accumulation of Dox. Additionally, the cytotoxic effect of eight compounds, isolated from this extract, that is, 2,4-dihydroxy-3-methylacetophenone-(C1), nortryptoquivaline-(C2), chevalone C-(C3), tryptoquivaline H-(C4), fiscalin A-(C5), epi-fiscalin-C (C6), epi-neofiscalin A-(C7), and epi-fiscalin A-(C8), alone and combined with Dox was also evaluated in lung cancer cells. The cytotoxic effect of Dox was potentiated by all the isolated compounds (except C1) in A549 cells. Therefore, we concluded that NS extract potentiated cytotoxicity by inhibiting cell proliferation, increasing intracellular accumulation of Dox, and inducing cell death (possibly by an autophagic process). The isolated compounds also enhanced the activity of Dox, supporting the potential of this sort of combination. These data call for further studies to characterize drug interactions and underlying mechanisms.

Design, Synthesis and Biological Evaluation of Jahanyne Analogs as Cell Cycle Arrest Inducers

Jahanyne, a lipopeptide with a unique terminal alkynyl and OEP (2-(1-oxo-ethyl)-pyrrolidine) moiety, exhibits anticancer activity. We synthesized jahanyne and analogs modified at the OEP moiety, employing an α-fluoromethyl ketone (FMK) strategy. Preliminary bioassays indicated that compound 1b (FMK-jahanyne) exhibited decreased activities to varying degrees against most of the cancer cells tested, whereas the introduction of a fluorine atom to the α-position of a hydroxyl group (2b) enhanced activities against all lung cancer cells. Moreover, jahanyne and 2b could induce G0/G1 cell cycle arrest in a concentration-dependent manner.

Carotenoids from Cyanobacteria: A Biotechnological Approach for the Topical Treatment of Psoriasis

In this study, five cyanobacteria strains (Alkalinema aff. pantanalense LEGE15481, Cyanobium gracile LEGE12431, Nodosilinea (Leptolyngbya) antarctica LEGE13457, Cuspidothrix issatschenkoi LEGE03282 and Leptolyngbya-like sp. LEGE13412) from the Blue Biotechnology and Ecotoxicology Culture Collection (LEGE CC) of CIIMAR were explored for their biotechnological potential in the treatment of psoriasis. Different extracts were characterized for their pigment profile by HPLC-PDA. The antioxidant potential of the extracts was assessed against the superoxide anion radical (O₂^•-). Their anti-inflammatory and antiproliferative potential was assessed in vitro using the macrophages RAW 264.7 and the human keratinocytes HaCaT as cell-line models, respectively. Terrestrial and freshwater strains presented the highest carotenoid content (33193-63926 μg/g dry extract), with all-trans-β-carotene, zeaxanthin, echinenone and lutein derivatives being the most abundant carotenoids. Acetone was the most effective solvent for pigment extraction. The acetone extracts presented the lowest IC₅₀ values (0.29-0.38 mg dry extract/mL) regarding O₂^•- scavenging, and revealed anti-inflammatory potential, with N. antarctica LEGE13457, A. pantanalense LEGE15481 and Leptolyngbya-like sp. LEGE13412 reducing the nitric oxide (NO) in RAW 264.7 cell culture medium in about 25% (p < 0.05). With the exception of A. pantanalense LEGE15481, all the extracts significantly reduced keratinocyte proliferation (p < 0.05), demonstrating a selective toxicity among the different cell lines. Overall, Leptolyngbya-like sp. LEGE13412 and N. antarctica LEGE13457 seem promising for further exploitation in the framework of psoriasis, due to their antioxidant, anti-inflammatory and antiproliferative potential.

Bioprospecting Sponge-Associated Marine Cyanobacteria to Produce Bioactive Compounds

Marine cyanobacteria are considered a prolific source of bioactive natural products with a range of biotechnological and pharmacological applications. However, data on the production of natural compounds from sponge-associated cyanobacteria are scarce. This study aimed to assess the potential of sponge-associated cyanobacteria strains representing different taxonomic groups for the production of bioactive compounds and the biological activity of their extracts. Phylogenetic analysis of sponge-associated cyanobacteria and screening for the presence of genes encoding non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) were performed. Methanol extracts of the sponge-associated strains were analyzed for cyanotoxin production and tested for antioxidant activity and cytotoxic activity against several human cancer cell lines and pathogenic bacteria. PKS were detected in all sponge-associated strains examined, indicating the metabolic potential of the isolates. PKS genes were more ubiquitous than NRPS genes. Cyanotoxins (i.e., cylindrospermopsin, anatoxin-a, nodularin, and microcystins) were not detected in any of the sponge-associated cyanobacterial strains. Strains belonging to Leptothoe, Pseudanabaena, and Synechococcus were found to have activity mainly against Staphylococcus aureus. In addition, sponge-associated Leptothoe strains (TAU-MAC 0915, 1015, 1115, and 1215) were found to be highly cytotoxic and in most cases more effective against human cancer cell lines than against normal cells. Extracts with the most promising bioactivity deserve further investigation in order to isolate and identify the bioactive molecule(s).

Dereplication of Natural Products with Antimicrobial and Anticancer Activity from Brazilian Cyanobacteria

Cyanobacteria are photosynthetic organisms that produce a large diversity of natural products with interesting bioactivities for biotechnological and pharmaceutical applications. Cyanobacterial extracts exhibit toxicity towards other microorganisms and cancer cells and, therefore, represent a source of potentially novel natural products for drug discovery. We tested 62 cyanobacterial strains isolated from various Brazilian biomes for antileukemic and antimicrobial activities. Extracts from 39 strains induced selective apoptosis in acute myeloid leukemia (AML) cancer cell lines. Five of these extracts also exhibited antifungal and antibacterial activities. Chemical and dereplication analyses revealed the production of nine known natural products. Natural products possibly responsible for the observed bioactivities and five unknown, chemically related chlorinated compounds present only in Brazilian cyanobacteria were illustrated in a molecular network. Our results provide new information on the vast biosynthetic potential of cyanobacteria isolated from Brazilian environments.

Tolyporphins L-R: Unusual Tetrapyrroles from a Brasilonema sp. of Cyanobacterium

Tolyporphins L-R (2-8) have been isolated from a mixed cyanobacterium-microbial culture. The structures of tolyporphins L and M have been revised to four constitutional isomers, isolated as two mixtures of dioxobacteriochlorins (2/3 and 4/5). In contrast, tolyporphin P (6) is a fully oxidized tetrapyrrole, while tolyporphins Q and R (7 and 8) are oxochlorins. X-ray structures are reported for the first time for tolyporphins A (1), R (8), and E (9), revealing unexpected stereochemical variation within the series.

Designing, synthesis and characterization of 2-aminothiazole-4-carboxylate Schiff bases; antimicrobial evaluation against multidrug resistant strains and molecular docking

BACKGROUND

2-Aminothiazoles are significant class of organic medicinal compounds utilized as starting material for the synthesis of diverse range of heterocyclic analogues with promising therapeutic roles as antibacterial, antifungal, anti-HIV, antioxidant, antitumor, anthelmintic, anti-inflammatory & analgesic agents.

EXPERIMENTAL

Eight compounds 1a, 2a-2g were synthesized and characterized by FTIR and NMR (1H and 13C). Evaluation of antibacterial potential against multi-drug resistant clinical isolates was performed and minimum inhibitory concentration (MIC) values were determined. Antifungal activity was also performed. Protein-ligand interactions of compounds with target enzyme were evaluated through docking studies.

RESULTS

Resistance profiling of bacterical clinical isolates (MDRs) depicted that some standard drugs used were not active against these MDRs while our synthesized compounds showed good MIC values. Among all the synthesized compounds, 2a and 2b showed significant antibacterial potential towards gram-positive Staphylococcus epidermidis and gram-negative Pseudomonas aeruginosa at MIC 250 µg/mL and 375 µg/mL respectively. Likewise, compound 2d and 2g exhibited inhibitory potential against gram-positive Staphylococcus aureus and gram-negative Escherichia coli at MIC values of 250 and 375 µg/mL respectively. Compound 2b showed maximum antifungal potential against Candida glabrata (ATCC 62934) with a zone of inhibition 21.0 mm as compared to the reference drug nystatin which showed lesser antifungal potential with a zone of inhibition of 19.1 mm. Candida albicans (ATCC 60387) showed maximum sensitivity to compound 2a with a zone of inhibition 20.0 mm. Its antifungal activity is more in comparison to reference drug nystatin with exhibited the zone of inhibition of 19.3 mm. Designed compounds were docked with the target enzyme UDP-N-acetylmuramate/l-alanine ligase. The compound 2b showed highest binding affinity (- 7.6 kcal/mol).

CONCLUSIONS

The synthesized compounds showed moderate to significant antibacterial and antifungal potential. It is clear from the binding affinities that compounds having hydroxyl group substituted on benzene ring possess strong binding affinity as compared to other analogues. These designed compounds could be considered to act as antagonists against target UDP-N-acetylmuramate/l-alanine ligase.

A new active peptide from Neptunea arthritica cumingii exerts protective effects against gentamicin-induced sensory-hair cell injury in zebrafish

Gentamicin is commonly used for effective treatment of severe Gram-negative bacterial infections. However, its use is being increasingly restricted owing to the ototoxic effects attributed to it. Gentamicin-induced ototoxicity is thought to be related with apoptosis induced by reactive oxygen species (ROS). In this study, we found a novel active peptide from Neptunea arthritica cumingii with otoprotective effects and no significant embryotoxic effects. The combined application of gentamicin and this novel active peptide helped sensory-hair cells to protect themselves from lethal ROS accumulation. This, in turn, reduced the expression of three genes (caspase-3, caspase-9, Bax), and thereby, the sensory-hair cell apoptosis promoted by ROS accumulation upon gentamicin administration. Our findings provided new insights into the prevention of gentamicin-induced hearing loss.

Marine Natural Products: A Source of Novel Anticancer Drugs

Cancer remains one of the most lethal diseases worldwide. There is an urgent need for new drugs with novel modes of action and thus considerable research has been conducted for new anticancer drugs from natural sources, especially plants, microbes and marine organisms. Marine populations represent reservoirs of novel bioactive metabolites with diverse groups of chemical structures. This review highlights the impact of marine organisms, with particular emphasis on marine plants, algae, bacteria, actinomycetes, fungi, sponges and soft corals. Anti-cancer effects of marine natural products in in vitro and in vivo studies were first introduced; their activity in the prevention of tumor formation and the related compound-induced apoptosis and cytotoxicities were tackled. The possible molecular mechanisms behind the biological effects are also presented. The review highlights the diversity of marine organisms, novel chemical structures, and chemical property space. Finally, therapeutic strategies and the present use of marine-derived components, its future direction and limitations are discussed.

Marine Natural Products: A Source of Novel Anticancer Drugs

Cancer remains one of the most lethal diseases worldwide. There is an urgent need for new drugs with novel modes of action and thus considerable research has been conducted for new anticancer drugs from natural sources, especially plants, microbes and marine organisms. Marine populations represent reservoirs of novel bioactive metabolites with diverse groups of chemical structures. This review highlights the impact of marine organisms, with particular emphasis on marine plants, algae, bacteria, actinomycetes, fungi, sponges and soft corals. Anti-cancer effects of marine natural products in in vitro and in vivo studies were first introduced; their activity in the prevention of tumor formation and the related compound-induced apoptosis and cytotoxicities were tackled. The possible molecular mechanisms behind the biological effects are also presented. The review highlights the diversity of marine organisms, novel chemical structures, and chemical property space. Finally, therapeutic strategies and the present use of marine-derived components, its future direction and limitations are discussed.

Algae metabolites: from in vitro growth inhibitory effects to promising anticancer activity

Covering: 1957 to 2017 Algae constitute a heterogeneous group of eukaryotic photosynthetic organisms, mainly found in the marine environment. Algae produce numerous metabolites that help them cope with the harsh conditions of the marine environment. Because of their structural diversity and uniqueness, these molecules have recently gained a lot of interest for the identification of medicinally useful agents, including those with potential anticancer activities. In the current review, which is not a catalogue-based one, we first highlight the major biological events that lead to various types of cancer, including metastatic ones, to chemoresistance, thus to any types of current anticancer treatment relating to the use of chemotherapeutics. We then review algal metabolites for which scientific literature reports anticancer activity. Lastly, we focus on algal metabolites with promising anticancer activity based on their ability to target biological characteristics of cancer cells responsible for poor treatment outcomes. Thus, we highlight compounds that have, among others, one or more of the following characteristics: selectivity in reducing the proliferation of cancer cells over normal ones, potential for killing cancer cells through non-apoptotic signaling pathways, ability to circumvent MDR-related efflux pumps, and activity in vivo in relevant pre-clinical models.

Characterization of Drug-like Chemical Space for Cytotoxic Marine Metabolites Using Multivariate Methods

In the last few decades, marine metabolites have been exploited to find commercially viable products in several areas. In this article, molecular descriptors [log P, mass, total polar surface area (TPSA), H-bond donor, H-bond acceptor, and the number of rotatable bonds] for the marine-derived cytotoxic metabolites were calculated and compared with marketed anticancer drugs to understand their position in the drug-like space. Marine-based cytotoxic metabolites are divided into highly toxic (HT) and moderately toxic (MT) classes. The marketed anticancer drugs complied well with Lipinski's rule of five for all molecular descriptors. The majority of HT and MT metabolites complied solely with H-bond donors and a number of rotatable bonds with the Lipinski cutoff values. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were also performed using 73 molecular descriptors on an ensemble of highly cytotoxic or moderately cytotoxic marine metabolites and the marketed reference drugs. The HCA results showed that 12% of marine metabolites clustered with the marketed anticancer drugs and many of them had structural scaffold homology. The PCA results revealed the presence of a clear distinction between the cytotoxic marine metabolites and the marketed anticancer drugs. Results indicate that mass, TPSA, and log P are the vital parameters and the careful optimization of these parameters for marine cytotoxic metabolites may generate more meaningful anticancer candidates in the future.

New Drugs from the Sea: Pro-Apoptotic Activity of Sponges and Algae Derived Compounds

Natural compounds derived from marine organisms exhibit a wide variety of biological activities. Over the last decades, a great interest has been focused on the anti-tumour role of sponges and algae that constitute the major source of these bioactive metabolites. A substantial number of chemically different structures from different species have demonstrated inhibition of tumour growth and progression by inducing apoptosis in several types of human cancer. The molecular mechanisms by which marine natural products activate apoptosis mainly include (1) a dysregulation of the mitochondrial pathway; (2) the activation of caspases; and/or (3) increase of death signals through transmembrane death receptors. This great variety of mechanisms of action may help to overcome the multitude of resistances exhibited by different tumour specimens. Therefore, products from marine organisms and their synthetic derivates might represent promising sources for new anticancer drugs, both as single agents or as co-adjuvants with other chemotherapeutics. This review will focus on some selected bioactive molecules from sponges and algae with pro-apoptotic potential in tumour cells.

Two Novel Multi-Functional Peptides from Meat and Visceral Mass of Marine Snail Neptunea arthritica cumingii and Their Activities In Vitro and In Vivo

Neptunea arthritica cumingii (Nac) is a marine snail with high nutritional and commercial value; however, little is known about its active peptides. In this study, two multi-functional peptides, YSQLENEFDR (Tyr-Ser-Gln-Leu-Glu-Asn-Glu-Phe-Asp-Arg) and YIAEDAER (Tyr-Ile-Ala-Glu-Asp-Ala-Glu-Arg), were isolated and purified from meat and visceral mass extracts of Nac using a multi-bioassay-guided method and were characterized by using liquid chromatography-tandem mass spectrometry. Both peptides showed high antioxidant, angiotensin-converting enzyme (ACE)-inhibitory, and anti-diabetic activities, with half-maximal effective concentrations values less than 1 mM. Antioxidant and ACE-inhibitory activities were significantly higher for YSQLENEFDR than for YIAEDAER. In a zebrafish model, the two peptides exhibited strong scavenging ability for reactive oxygen species and effectively protected skin cells against oxidative damage without toxicity. Molecular docking simulation further predicted the interactions of the two peptides and ACE. Stability analysis study indicated that the two synthetic peptides maintained their activities under thermal stress and simulated gastrointestinal digestion conditions. The low molecular weight, high proportion of hydrophobic and negatively-charged amino acids, and specific C-terminal and N-terminal amino acids may contribute to the observed bio-activities of these two peptides with potential application for the prevention of chronic noncommunicable diseases.

First evidence of Halomicronema metazoicum (Cyanobacteria) free-living on Posidonia oceanica leaves

Cyanobacteria contribute to the ecology of various marine environments, also for their symbioses, since some of them are common hosts of sponges and ascidians. They are also emerging as an important source of novel bioactive secondary metabolites in pharmacological (as anticancer drugs) and biotechnological applications. In the present work we isolated a cyanobacteria in a free-living state from leaves of the seagrass Posidonia oceanica leaves. This newly collected strain was then cultivated under two laboratory conditions, and then characterized by combining morphological observation and molecular studies based on 16S rRNA gene sequences analysis. The strain showed 99% pairwise sequence identity with Halomicronema metazoicum ITAC101, never isolated before as a free-living organisms, but firstly described as an endosymbiont of the Mediterranean marine spongae Petrosia ficiformis, under the form of a filamentous strain. Further studies will investigate the actual role of this cyanobacterium in the leaf stratum of P. oceanica leaves, given its demonstrated ability to influence the vitality and the life cycle of other organisms. In fact, its newly demonstrated free-living stage, described in this study, indicate that Phormidium-like cyanobacteria could play important roles in the ecology of benthic and planktonic communities.

Total Synthesis of the Highly N-Methylated Peptides Carmabin A and Dragomabin

The first total synthesis of carmabin A and dragomabin was achieved at 52.3 mg and 43.8 mg scale, respectively. The synthesis led to determination of the configuration of carmabin A and reassignment of the configuration of dragomabin at the stereogenic centre on the alkyne-bearing fragment.

Cyanopeptolins with Trypsin and Chymotrypsin Inhibitory Activity from the Cyanobacterium Nostoc edaphicum CCNP1411

Cyanopeptolins (CPs) are one of the most frequently occurring cyanobacterial peptides, many of which are inhibitors of serine proteases. Some CP variants are also acutely toxic to aquatic organisms, especially small crustaceans. In this study, thirteen CPs, including twelve new variants, were detected in the cyanobacterium Nostoc edaphicum CCNP1411 isolated from the Gulf of Gdańsk (southern Baltic Sea). Structural elucidation was performed by tandem mass spectrometry with verification by NMR for CP962 and CP985. Trypsin and chymotrypsin inhibition assays confirmed the significance of the residue adjacent to 3-amino-6-hydroxy-2-piperidone (Ahp) for the activity of the peptides. Arginine-containing CPs (CPs-Arg²) inhibited trypsin at low IC₅₀ values (0.24⁻0.26 &micro;M) and showed mild activity against chymotrypsin (IC₅₀ 3.1⁻3.8 &micro;M), while tyrosine-containing CPs (CPs-Tyr²) were selectively and potently active against chymotrypsin (IC₅₀ 0.26 &micro;M). No degradation of the peptides was observed during the enzyme assays. Neither of the CPs were active against thrombin, elastase or protein phosphatase 1. Two CPs (CP962 and CP985) had no cytotoxic effects on MCF-7 breast cancer cells. Strong and selective activity of the new cyanopeptolin variants makes them potential candidates for the development of drugs against metabolic disorders and other diseases.

Apoptosis as a Mechanism of the Cancer Chemopreventive Activity of Glucosinolates: a Review

Cruciferous vegetables are a rich source of glucosinolates that have established anti-carcinogenic activity. Naturally-occurring glucosinolates and their derivative isothiocyanates (ITCs), generated as a result of their enzymatic degradation catalysed by myrosinase, have been linked to low cancer incidence in epidemiological studies, and in animal models isothiocyanates suppressed chemically-induced tumorigenesis. The prospective effect of isothiocyanates as anti-carcinogenic agent has been much explored as cytotoxic against wide array of cancer cell lines and being explored for the development of new anticancer drugs. However, the mechanisms of isothiocyanates in inducing apoptosis against tumor cell lines are still largely disregarded. A number of mechanisms are believed to be involved in the glucosinolate-induced suppression of carcinogenesis, including the induction of apoptosis, biotransformation of xenobiotic metabolism, oxidative stress, alteration of caspase activity, angiogenesis, histone deacytylation and cell cycle arrest. The molecular mechanisms through which isothiocyanates stimulate apoptosis in cancer cell lines have not so far been clearly defined. This review summarizes the underlying mechanisms through which isothiocyanates modify the apoptotic pathway leading to cell death.

Selected Methods of Extracting Carotenoids, Characterization, and Health Concerns: A Review

Carotenoids are the most powerful nutrients (medicine) on earth due to their potent antioxidant properties. The ability of these tetraterpenoids in obviating human chronic ailments like cancer, cardiovascular disease, osteoporosis, and diabetes has drawn public attention toward these novel compounds. Conventionally, carotenoids have been extracted from plant materials and agro-industrial byproduct using different solvents, but these procedures result in contaminating the target compound (carotenoids) with extraction solvents. Furthermore, some utilized solvents are not safe and hence are harmful to the environment. This has attracted criticism from consumers, ecologists, environmentalists, and public health workers. However, there is clear consumer preference for carotenoids from natural origin without traces of extracting solvent. Therefore, this review seeks to discuss methods for higher recovery of pure carotenoids without contamination from a solvent. Methods such as enzyme-based extraction, supercritical fluid extraction, microwave-assisted extraction, Soxhlet extraction, ultrasonic extraction, and postextraction treatment (saponification) are discussed. Merits and demerits of these methods along with health concerns during intake of carotenoids were also considered.

Investigation of the Anti-Prostate Cancer Properties of Marine-Derived Compounds

This review focuses on marine compounds with anti-prostate cancer properties. Marine species are unique and have great potential for the discovery of anticancer drugs. Marine sources are taxonomically diverse and include bacteria, cyanobacteria, fungi, algae, and mangroves. Marine-derived compounds, including nucleotides, amides, quinones, polyethers, and peptides are biologically active compounds isolated from marine organisms such as sponges, ascidians, gorgonians, soft corals, and bryozoans, including those mentioned above. Several compound classes such as macrolides and alkaloids include drugs with anti-cancer mechanisms, such as antioxidants, anti-angiogenics, antiproliferatives, and apoptosis-inducing drugs. Despite the diversity of marine species, most marine-derived bioactive compounds have not yet been evaluated. Our objective is to explore marine compounds to identify new treatment strategies for prostate cancer. This review discusses chemically and pharmacologically diverse marine natural compounds and their sources in the context of prostate cancer drug treatment.

Phenotypic and genotypic characterisation of an unique indigenous hypersaline unicellular cyanobacterium, Euhalothece sp.nov

A novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment composition and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14-18 μm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the 'Euhalothece' subcluster (99%). The whole genome sequence was determined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxidative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.

Total Synthesis of Kanamienamide

Kanamienamide is a novel enol ether containing enamide with a single digit micromolar inhibitory activity against cancer cell lines. An efficient and convergent total synthesis of kanamienamide has been developed for the first time, which features a Cu-mediated amide coupling with vinyl iodide at the late stage. Other key transformations include Evans asymmetric alkylation, CBS asymmetric reduction, ring-closing metathesis reaction, and Stork-Zhao-Wittig olefination. This strategy is amenable for facile analogue preparation and SAR studies.

Imminent Angiotensin-converting Enzyme Inhibitor from Microbial Source for Cancer Therapy

Background

Drugs targeting Angiotensin I-converting enzyme (ACE) have been used broadly in cancer chemotherapy. The recent past coupled with our results demonstrates the effective use of ACE inhibitors (ACEi) as anticancer agents, and they are potentially relevant in deriving new inhibitors.

Methods

Bacterial strains were isolated from cow milk collected in Coimbatore, Tamil Nadu, India and plated on nutrient agar medium. The identity of the strain was ascertained by 16s rRNA gene sequencing method and was submitted to the NCBI GenBank nucleotide database. Various substrates were screened for ACEi production by the fermentation with the isolated strain. ACEi was purified by sequential steps of ethanol precipitation, ion exchange column chromatography and gel filtration column chromatography. The apparent molecular mass was determined by SDS-PAGE. The anticancer property was analyzed by studying the cytotoxicity effects of ACEi using Breast cancer MCF-7 cell lines.

Results

The isolate coded as BUCTL09 was selected and identified as Micrococcus luteus. Among the seven substrates, only beef extract fermented broth showed an inhibition of 79% and was reported as the best substrate. The peptide was purified and molecular mass was determined. The IC50 value of peptide was found to be 59.5 μg/ml. The purified peptide has demonstrated to induce apoptosis of cancer cell.

Conclusions

The results of this study revealed that Peptide has been determined as an active compound that inhibited the activity of ACE. These properties indicate the possibilities of the use of purified protein as a potent anticancer agent.