A polybromodiphenyl ether from an Indonesian marine sponge Lamellodysidea herbacea and its chemical derivatives inhibit protein tyrosine phosphatase 1B, an important target for diabetes treatment

Revolutionizing Diabetes Care: The Role of Marine Bioactive Compounds and Microorganisms

Diabetes is a metabolic condition characterized by high blood glucose levels. Aquatic products like microalgae, bacteria, seagrasses, macroalgae, corals, and sponges have been investigated for potential anti-diabetic properties. We looked at polyphenols, peptides, pigments, and sterols, as well as other bioactive substances found in marine resources, to see if they could help treat or manage diabetes, in addition to describing the several treatment strategies that alter diabetes and its implications, such as inhibition of protein tyrosine phosphatases 1B (PTP1B), α-glucosidase, α-amylase, dipeptidyl peptidase IV (DPP-IV), aldose reductase, lipase, glycogen synthase kinase 3β (GSK-3β), and insulin resistance prevention, promotion of liver antioxidant capacity, natural killer cell stimulant, anti-inflammatory actions, increased AMP-activated protein kinase (AMPK) phosphorylation and sugar and metabolism of the lipid, reducing oxidative stress, and β-pancreatic cell prevention. This study highlights the revolutionary potential of marine bioactive compounds and microorganisms in transforming diabetes care. We believe in a future in which innovative, sustainable, and efficient therapeutic approaches will result in improved quality of life and better outcomes for people with diabetes mellitus by forging a new path for treatment, utilizing the power of the world's oceans, and capitalizing on the symbiotic relationship between humans and the marine ecosystem. This study area offers optimism and promising opportunities for transforming diabetes care.

Design and Synthesis of Marine Polybrominated Diphenyl Ether Derivatives as Potential Anti-Inflammatory Agents

Natural polybrominated diphenyl ethers are generally isolated from sponges and possess a broad range of biological activities. Through screening of our marine natural product library, we discovered that polybrominated diphenyl ethers 5 and 6 exhibit considerable anti-inflammatory activity. In order to expand our repertoire of derivatives for further biological activity studies, we designed and synthesized a series of 5-related polybrominated diphenyl ethers. Importantly, compound 5a showed comparable anti-inflammatory activity while much lower cytotoxicity on lipopolysaccharide (LPS)-induced RAW264.7 cells. Additionally, western blotting analysis showed that 5a reduced the expression of phosphorylated extracellular signal-regulated kinase (p-ERK). Besides, molecular docking experiments were conducted to predict and elucidate the potential mechanisms underlying the varying anti-inflammatory activities exhibited by compounds 5a, 5, and 6.

Natural Bioactive Compounds from Marine Invertebrates That Modulate Key Targets Implicated in the Onset of Type 2 Diabetes Mellitus (T2DM) and Its Complications

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an ongoing, risky, and costly health problem that therefore always requires new treatment options. Moreover, although several drugs are available, only 36% of patients achieve glycaemic control, and patient adherence is a major obstacle. With monotherapy, T2DM and its comorbidities/complications often cannot be managed, and the concurrent administration of several hypoglycaemic drugs is required, which increases the risk of side effects. In fact, despite the efficacy of the drugs currently on the market, they generally come with serious side effects. Therefore, scientific research must always be active in the discovery of new therapeutic agents.

DISCUSSION

The present review highlights some of the recent discoveries regarding marine natural products that can modulate the various targets that have been identified as crucial in the establishment of T2DM disease and its complications, with a focus on the compounds isolated from marine invertebrates. The activities of these metabolites are illustrated and discussed.

OBJECTIVES

The paper aims to capture the relevant evidence of the great chemical diversity of marine natural products as a key tool that can advance understanding in the T2DM research field, as well as in antidiabetic drug discovery. The variety of chemical scaffolds highlighted by the natural hits provides not only a source of chemical probes for the study of specific targets involved in the onset of T2DM, but is also a helpful tool for the development of drugs that are capable of acting via novel mechanisms. Thus, it lays the foundation for the design of multiple ligands that can overcome the drawbacks of polypharmacology.

Hypoglycaemic Molecules for the Management of Diabetes Mellitus from Marine Sources

Diabetes mellitus (DM) is a chronic metabolic disorder recognized as a major health problem globally. A defective insulin activity contributes to the prevalence and expansion of DM. Treatment of DM is often hampered by limited options of conventional therapies and adverse effects associated with existing procedures. This has led to a spike in the exploration for potential therapeutic agents from various natural resources for clinical applications. The marine environment is a huge store of unexplored diversity of chemicals produced by a multitude of organisms. To date, marine microorganisms, microalgae, macroalgae, corals, sponges, and fishes have been evaluated for their anti-diabetic properties. The structural diversity of bioactive metabolites discovered has shown promising hypoglycaemic potential through in vitro and in vivo screenings via various mechanisms of action, such as PTP1B, α-glucosidase, α-amylase, β-glucosidase, and aldose reductase inhibition as well as PPAR alpha/gamma dual agonists activities. On the other hand, hypoglycaemic effect is also shown to be exerted through the balance of antioxidants and free radicals. This review highlights marine-derived chemicals with hypoglycaemic effects and their respective mechanisms of action in the management of DM in humans.

Germacrane sesquiterpenes from leaves of Eupatorium chinense inhibit protein tyrosine phosphatase

Three new germacrane-type sesquiterpene lactones (1-3) were isolated alongside seven known related congeners (4-10) from the leaves of Eupatorium chinense L. (Compositae). The planar structures of 1-3 were elucidated by their spectroscopic data, including 1D and 2D NMR spectra. The relative and absolute configurations of 1-3 were determined using NOESY experiments and electronic circular dichroism analyses. Compounds 1, 4, 5, and 7 inhibited protein tyrosine phosphatase (PTP) 1B activity with IC₅₀ values of 25, 11, 28, and 24 μM, respectively. Among these, compound 4 exhibited an inhibitory effect on T-cell PTP (TCPTP) with an IC₅₀ value of 25 μM. To our knowledge, this is the first study demonstrating the PTP inhibitory activity of the germacrane sesquiterpenes. The results show that compound 4 acts as an inhibitor of both PTP1B and TCPTP.

Ecological and Pharmacological Activities of Polybrominated Diphenyl Ethers (PBDEs) from the Indonesian Marine Sponge Lamellodysidea herbacea

Two known Polybrominated Diphenyl Ethers (PBDEs), 3,4,5-tribromo-2-(2′,4′-dibromophenoxy)phenol (1d) and 3,4,5,6-tetrabromo-2-(2′,4′-dibromophenoxy)phenol (2b), were isolated from the Indonesian marine sponge Lamellodysidea herbacea. The structure was confirmed using ¹³C chemical shift average deviation and was compared to the predicted structures and recorded chemical shifts in previous studies. We found a wide range of bioactivities from the organic crude extract, such as (1) a strong deterrence against the generalist pufferfish Canthigaster solandri, (2) potent inhibition against environmental and human pathogenic bacterial and fungal strains, and (3) the inhibition of the Hepatitis C Virus (HCV). The addition of a bromine atom into the A-ring of compound 2b resulted in higher fish feeding deterrence compared to compound 1d. On the contrary, compound 2b showed only more potent inhibition against the Gram-negative bacteria Rhodotorula glutinis (MIC 2.1 μg/mL), while compound 1d showed more powerful inhibition against the other human pathogenic bacteria and fungi. The first report of a chemical defense by compounds 1d and 2b against fish feeding and environmental relevant bacteria, especially pathogenic bacteria, might be one reason for the widespread occurrence of the shallow water sponge Lamellodysidea herbacea in Indonesia and the Indo-Pacific.

Exploration of marine natural resources in Indonesia and development of efficient strategies for the production of microbial halogenated metabolites

Nature is a prolific source of organic products with diverse scaffolds and biological activities. The process of natural product discovery has gradually become more challenging, and advances in novel strategic approaches are essential to evolve natural product chemistry. Our focus has been on surveying untouched marine resources and fermentation to enhance microbial productive performance. The first topic is the screening of marine natural products isolated from Indonesian marine organisms for new types of bioactive compounds, such as antineoplastics, antimycobacterium substances, and inhibitors of protein tyrosine phosphatase 1B, sterol O-acyl-transferase, and bone morphogenetic protein-induced osteoblastic differentiation. The unique biological properties of marine organohalides are discussed herein and attempts to efficiently produce fungal halogenated metabolites are documented. This review presents an overview of our recent work accomplishments based on the MONOTORI study.

Production of an α-pyrone metabolite and microbial transformation of isoflavones by an Indonesian Streptomyces sp

A benzyl-α-pyrone metabolite, streptpyrone A (1), was obtained together with three known isoflavonoids, daidzein-7-O-α-l-rhamnoside (2), genistein-7-O-α-l-rhamnoside (3), and daidzein (4), from the culture broth of an Indonesian actinomycete Streptomyces sp. TPU1401A. The structure of 1, elucidated based on its spectroscopic data, has been reported as a synthetic compound. However, this is the first report of the isolation of 1 as a metabolite of microbial origin. Strain TPU1401A exhibited the ability to transform the isoflavone aglycones 4 and genistein (5) into the 7-O-glycosides 2 and 3, respectively. Compounds 2 and 3 promoted the growth of strain TPU1401A more effectively than compounds 4 and 5. These results suggest that strain TPU1401A utilizes isoflavone glycosides to promote growth by transforming isoflavones through microbial glycosidation.

Structural and Bioactive Studies of Halogenated Constituents from Sponges

Marine organisms are abundant sources of bioactive natural products. Among metabolites produced by sponges and their associated microbial communities, halogenated natural compounds accounted for an important part due to their potent biological activities. The present review updates and compiles a total of 258 halogenated organic compounds isolated in the past three decades, especially brominated derivatives derived from 31 genera of marine sponges. These compounds can be classified as the following classes: brominated polyunsaturated lipids, nitrogen compounds, brominated tyrosine derivatives and other halogenated compounds. These substances were listed together with their source organisms, structures and bioactivities. For this purpose, 84 references were consulted.

Spirulina Platensis Supplementation Coupled to Strength Exercise Improves Redox Balance and Reduces Intestinal Contractile Reactivity in Rat Ileum

The blue alga Spirulina platensis has presented several pharmacological activities, highlighting its actions as an anti-inflammatory and antioxidant. In addition, there are few studies with the influence of strength training on physiological parameters, as intestinal contractility and oxidative cell damage. We evaluated the influence of S. platensis supplementation, strength training, and its association on contractile reactivity of rat ileum, as well as the balance of oxidative stress/antioxidant defenses. Methods: Male Wistar rats were divided into; sedentary (S); S + supplemented with algae at 50 (S50), 150 (S150), and 500 mg/kg (S500); trained (T); and T + supplemented (T50, T150, and T500). Contractile reactivity was analyzed by kymographs; oxidative stress on ileum by the malondialdehyde (MDA) formation; and the antioxidant capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. S. platensis supplementation reduced the reactivity of rat ileum to carbachol (CCh) and KCl, while training reduced only the CCh efficacy. In addition, association potentiated the reduction on contractile reactivity. Supplementation reduced the oxidative stress and increased oxidation inhibition; training alone did not alter this parameter, however association potentiated this beneficial effect. Therefore, this study demonstrated that both supplementation and its association with strength training promote beneficial effects regarding intestinal contractile reactivity and oxidative stress, providing new insights for intestinal disorders management.

Marine natural products from sponges (Porifera) of the order Dictyoceratida (2013 to 2019); a promising source for drug discovery

Marine organisms have been considered an interesting target for the discovery of different classes of secondary natural products with wide-ranging biological activities. Sponges which belong to the order Dictyoceratida are distinctly classified into 5 families: Dysideidae, Irciniidae, Spongiidae, Thorectidae, and Verticilliitidae. In this review, compounds isolated from Dictyoceratida sponges were discussed with their biological potential within the period 2013 to December 2019. Moreover, analysis of the physicochemical properties of these marine natural products was investigated and the results showed that 78% of the compounds have oral bioavailability potential. This review highlights sponges of the order Dictyoceratida as exciting source for discovery of new drug leads.

Marine organisms have been considered an interesting target for the discovery of different classes of secondary natural products with wide-ranging biological activities.

Osteoarthritis Is a Low-Grade Inflammatory Disease: Obesity's Involvement and Herbal Treatment

Osteoarthritis (OA) is considered a major cause of disability around the globe. This handicapping disease causes important cartilage and bone alteration that is associated with serious pains and loss of joint function. Despite its frequent association with obesity, the aetiology of OA is not fully understood. In this review, the different aspects of OA and its correlation with obesity were analysed. Through examining different mechanisms by which obesity may trigger and/or exacerbate OA, we point out some relevant signalling pathways that may evolve as candidates for pharmacological drug development. As such, we also suggest a review of different herbal medicines (HMs) and their main compounds, which specifically interfere with the identified pathways. We have shown that obesity's involvement in OA is not only limited to the mechanical weight exerted on the joints (mechanical hypothesis), but also induces an inflammatory state by different mechanisms, including increased leptin expression, compromised gut mucosa, and/or gut microbiota disruption. The main signalling pathways involved in OA inflammation, which are associated with obesity, are protein tyrosine phosphatase 1B (PTP1B) and TLR4 or DAP12. Moreover, we also underline the contamination of plant extracts with LPS as an important factor to consider when studying HM's effects on articular cells. By summarizing recent publications, this review aims at highlighting newly established aspects of obesity involvement in OA other than the mechanical one.

[Search for Protein Tyrosine Phosphatase 1B Inhibitors from Marine Organisms and Induced Production of New Fungal Metabolites by Modulating Culture Methods]

Marine environments offer a rich source of natural products with potential therapeutic applications because the ocean covers 70% of the earth's surface and approximately 80% of all living organisms live in the sea. Therefore we have investigated bioactive compounds from marine organisms such as marine sponges, ascidians, and marine-derived microorganisms. This review consists of two topics based on marine natural product chemistry. (1) Protein tyrosine phosphatase (PTP) 1B plays a key role as a negative regulator in the insulin and leptin signaling pathways. Accordingly, the development of PTP1B inhibitors is expected to provide new drugs for type 2 diabetes and obesity. We have been searching for new types of PTP1B inhibitors among marine organisms and identified various PTP1B inhibitors from marine sponges and fungi. This review presents their structural diversities and unique biological properties. (2) In the course of our studies on the induced production of new fungal metabolites, the Palauan marine-derived fungus, Trichoderma cf. brevicompactum TPU199, was found to produce the unusual epipolythiodiketopiperazines, gliovirin and pretrichodermamide A. Long-term static fermentation of the strain induced production of a new dipeptide, dithioaspergillazine A, whereas fermentation of the strain with NaCl, NaBr, and NaI produced the Cl and Br derivatives of pretrichodermamide A and a new iodinated derivative, iododithiobrevamide, respectively. Moreover, DMSO-added seawater medium induced the production of diketopiperazine with the unprecedented trithio-bridge, chlorotrithiobrevamide. This fermentation study on the strain as well as the structures of the metabolites obtained are described in this review.

Looking at Marine-Derived Bioactive Molecules as Upcoming Anti-Diabetic Agents: A Special Emphasis on PTP1B Inhibitors

Diabetes mellitus (DM) is a chronic metabolic disease with high morbimortality rates. DM has two types: type 1, which is often associated with a total destruction of pancreatic beta cells, and non-insulin-dependent or type 2 diabetes mellitus (T2DM), more closely associated with obesity and old age. The main causes of T2DM are insulin resistance and/or inadequate insulin secretion. Protein-tyrosine phosphatase 1B (PTP1B) negatively regulates insulin signaling pathways and plays an important role in T2DM, as its overexpression may induce insulin resistance. Thus, since PTP1B may be a therapeutic target for both T2DM and obesity, the search for novel and promising natural inhibitors has gained much attention. Hence, several marine organisms, including macro and microalgae, sponges, marine invertebrates, sea urchins, seaweeds, soft corals, lichens, and sea grasses, have been recently evaluated as potential drug sources. This review provides an overview of the role of PTP1B in T2DM insulin signaling and treatment, and highlights the recent findings of several compounds and extracts derived from marine organisms and their relevance as upcoming PTP1B inhibitors. In this systematic literature review, more than 60 marine-derived metabolites exhibiting PTP1B inhibitory activity are listed. Their chemical classes, structural features, relative PTP1B inhibitory potency (assessed by IC50 values), and structure⁻activity relationships (SARs) that could be drawn from the available data are discussed. The upcoming challenge in the field of marine research-metabolomics-is also addressed.

Absolute Structures of Wedelolide Derivatives and Structure-Activity Relationships of Protein Tyrosine Phosphatase 1B Inhibitory ent-Kaurene Diterpenes from Aerial Parts of Wedelia spp. Collected in Indonesia and Japan

Two sesquiterpene lactones with the (9R)-eudesman-9,12-olide framework, wedelolides I and J, have been isolated together with five eudesmanolide sesquiterpenes and twelve ent-kaurene diterpenes from the aerial parts of Indonesian Wedelia prostrata. The absolute configurations of wedelolides I and J, proposed in the previous communication, were proven by comparing their experimental Electronic Circular Dichroism (ECD) spectra with the calculated ECD spectrum of wedelolide I. The phytochemical study on the aerial parts of Okinawan Wedelia chinensis led to the isolation of three other eudesmanolide sesquiterpenes in addition to the three sesquiterpenes and eleven diterpenes isolated from the Indonesian W. prostrata as above. However, the wedelolide derivatives found in the Indonesian plant were not detected. Among these compounds, most of the diterpenes inhibited protein tyrosine phosphatase (PTP) 1B activity, and a structure-activity relationship study revealed that the cinnamoyl group enhanced inhibitory activity. Therefore, two ent-kaurene derivatives with and without a cinnamoyl group were examined for the ability to accumulate phosphorylated-Akt (p-Akt) because PTP1B dephosphorylates signal transduction from the insulin receptor such as phosphorylated Akt, a key downstream effector. However, neither compound enhanced insulin-stimulated p-Akt levels in two human hepatoma cell lines (Huh-7 and HepG2) at non-cytotoxic doses.

Cladosporamide A, a new protein tyrosine phosphatase 1B inhibitor, produced by an Indonesian marine sponge-derived Cladosporium sp

Cladosporamide A (1), a new protein tyrosine phosphatase (PTP) 1B inhibitor, was isolated together with a known prenylated flavanone derivative (2) from the culture broth of an Indonesian marine sponge-derived Cladosporium sp. TPU1507 by solvent extraction, ODS column chromatography, and preparative HPLC (ODS). The structure of 1 was elucidated based on 1D and 2D NMR data. Compound 1 modestly inhibited PTP1B and T-cell PTP (TCPTP) activities with IC₅₀ values of 48 and 54 μM, respectively. The inhibitory activity of 2 against PTP1B (IC₅₀ = 11 μM) was approximately 2-fold stronger than that against TCPTP (IC₅₀ = 27 μM).

Meroterpenoids with Protein Tyrosine Phosphatase 1B Inhibitory Activity from a Hyrtios sp. Marine Sponge

Three new meroterpenoids, hyrtiolacton A (1), nakijinol F (2), and nakijinol G (3), along with three known ones, nakijinol B (4), nakijinol E (5), and dactyloquinone A (6), were isolated and characterized from a Hyrtios sp. marine sponge collected from the South China Sea. The new structures were determined based on extensive analysis of HRESIMS and NMR data, and their absolute configurations were assigned by a combination of single-crystal X-ray diffraction and electronic circular dichroism analyses. Hyrtiolacton A (1) represents an unprecedented meroterpenoid featuring an unusual 2-pyrone attached to the sesquiterpene core, which is the first example of a pyrone-containing 4,9-friedodrimane-type sesquiterpene. These compounds were evaluated for their protein tyrosine phosphatase (PTP1B) inhibitory and cytotoxic activities. Nakijinol G (3) showed PTP1B inhibitory activity with an IC₅₀ value of 4.8 μM but no cytotoxicity against four human cancer cell lines.

Inhibitors of Protein Tyrosine Phosphatase 1B from Marine Natural Products

The ocean is a capacious area with the most abundant biological resources on the earth. The particularity of the marine ecological environment (high pressure, high salt, and hypoxia) makes the marine species survival competition fiercely, forcing many marine organisms in the process of life to produce a great deal of secondary metabolites with special structures and biological activities. In this article, 118 natural products which were isolated from four kinds of marine organisms, sponges, algae, soft corals and fungus, showing PTP1B inhibitory activity were summarized from 2010 to 2016, which may become the leading compounds towards treating Diabetes mellitus (DM). What's more, we briefly summarized the structure-activity relationship of PTP1B inhibitors.

New amides from seeds of Silybum marianum with potential antioxidant and antidiabetic activities

Two new amide compounds, mariamides A and B (1-2), were obtained together with fourteen known compounds from the seeds of milk thistle (Silybum marianum). Their structures were established on the basis of extensive 1D and 2D NMR analyses, as well as HR-ESI-MS data. Most of the compounds showed significant antioxidant activities than positive control in ABTS and FRAP assays. However, only amide compounds 1-4 showed moderate DPPH radical scavenging activity and compounds 7 and 16 showed the most potent activity against DPPH. Most of the compounds showed moderate to stronger α-glucosidase inhibitory activities. Nevertheless, only flavonoids showed strong PTP1B inhibitory activities. These results indicate a use of milk thistle seed extracts as promising antioxidant and antidiabetic agents.

A new biphenyl ether derivative produced by Indonesian ascidian-derived Penicillium albobiverticillium

A new biphenyl ether derivative, 2-hydroxy-6-(2'-hydroxy-3'-hydroxymethyl-5-methylphenoxy)-benzoic acid (1), was isolated together with the known benzophenone derivative, monodictyphenone (2), from a culture broth of Indonesian ascidian-derived Penicillium albobiverticillium TPU1432 by solvent extraction, ODS column chromatography, and preparative HPLC (ODS). The structure of 1 was elucidated based on NMR experiments. Compound 2 exhibited moderate inhibitory activities against protein tyrosine phosphatase (PTP) 1B, T cell PTP (TCPTP), and CD45 tyrosine phosphatase (CD45), whereas compound 1 modestly inhibited CD45 activity.

Bioactive alkaloids from the aerial parts of Houttuynia cordata

ETHNOPHARMACOLOGICAL RELEVANCE

Houttuynia cordata is an important traditional Chinese medicine used in heat-clearing and detoxifying, swelling and discharging pus, promoting diuresis and relieving stranguria which recorded in Pharmacopoeia of the people's Republic of China (2015 Edition). H. cordata has been recorded in the book Bencaogangmu which was written by Shizhen Li for the treatment of pyretic toxicity, carbuncle swelling, haemorrhoids, and rectocele diseases.

AIM OF THE STUDY

Phytochemical investigation of the aerial parts of H. cordata and evaluation of their PTP1B inhibitory activities and hepatoprotective activities.

MATERIALS AND METHODS

The dried aerial parts of H. cordata were fractionated by liquid-liquid extraction to obtain CHCl₃, ethyl acetate, and n-butanolic fractions. The CHCl₃ fraction was confirmed active fraction by the bioactivity-guided investigation, which was isolated and purified by chromatographing over silica gel, Sephadex LH-20, MPLC, and preparative HPLC. The chemical structures of the purified compounds were identified by their spectroscopic data and references.

RESULTS

Eight new compounds (1-8), together with fourteen known compounds (9-22) were isolated from the aerial parts of H. cordata. The known compounds (9-22) were obtained from this plant for the first time. Among them, some compounds exhibited moderate bioactivities.

CONCLUSION

Compounds (1-8) were identified as new alkaloids, and the known alkaloids (9-22) were isolated from this plant for the first time. Compounds 1, 4, 14, and 19 showed significant PTP1B inhibitory activities with IC₅₀ values of 1.254, 2.016, 2.672, and 1.862µm, respectively. Compounds 1, 3, 6, 11, 17, and 20 (10µm) exhibited moderate hepatoprotective activities against D-galactosamine-induced WB-F344 cells damage.

A tetramic acid derivative with protein tyrosine phosphatase 1B inhibitory activity and a new nortriterpene glycoside from the Indonesian marine sponge Petrosia sp

During the search for protein tyrosine phosphatase 1B (PTP1B) inhibitors from marine organisms, the known tetramic acid derivative, melophlin C (1), was isolated as an active component together with the new nortriterpenoid saponin, sarasinoside S (2), and three homologues: sarasinosides A₁ (3), I₁ (4), and J (5), from the Indonesian marine sponge Petrosia sp. The structure of 2 was elucidated on the basis of its spectroscopic data. Compound 1 inhibited PTP1B activity with an IC₅₀ value of 14.6μM, while compounds 2-5 were not active at 15.2-16.0μM. This is the first study to report the inhibitory effects of a tetramic acid derivative on PTP1B activity.

Marine Organisms with Anti-Diabetes Properties

Diabetes is a chronic degenerative metabolic disease with high morbidity and mortality rates caused by its complications. In recent years, there has been a growing interest in looking for new bioactive compounds to treat this disease, including metabolites of marine origin. Several aquatic organisms have been screened to evaluate their possible anti-diabetes activities, such as bacteria, microalgae, macroalgae, seagrasses, sponges, corals, sea anemones, fish, salmon skin, a shark fusion protein as well as fish and shellfish wastes. Both in vitro and in vivo screenings have been used to test anti-hyperglycemic and anti-diabetic activities of marine organisms. This review summarizes recent discoveries in anti-diabetes properties of several marine organisms as well as marine wastes, existing patents and possible future research directions in this field.

Sesquiterpene Hydroquinones with Protein Tyrosine Phosphatase 1B Inhibitory Activities from a Dysidea sp. Marine Sponge Collected in Okinawa

Three new sesquiterpene hydroquinones, avapyran (1), 17-O-acetylavarol (2), and 17-O-acetylneoavarol (3), were isolated from a Dysidea sp. marine sponge collected in Okinawa together with five known congeners: avarol (4), neoavarol (5), 20-O-acetylavarol (6), 20-O-acetylneoavarol (7), and 3'-aminoavarone (8). The structures of 1-3 were assigned on the basis of their spectroscopic data. Compounds 1-3 inhibited the activity of protein tyrosine phosphatase 1B with IC50 values of 11, 9.5, and 6.5 μM, respectively, while known compounds 4-8 gave IC50 values of 12, >32, 10, 8.6, and 18 μM, respectively. In a preliminary investigation on structure-activity relationships, six ester and methoxy derivatives (9-14) were prepared from 4 and 5.

Structures and biological activities of triterpenes and sesquiterpenes obtained from Russula lepida

A seco-cucurbitane triterpene and two aristolane sesquiterpenes, named (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid, (+)-1,2-didehydro-9-hydroxy-aristlone, and (+)-12-hydroxy-aristlone, were isolated from fruiting bodies of the medicinal mushroom Russula lepida, together with (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid and (+)-aristlone. The structures of the first three compounds, including their absolute configurations, were assigned on the basis of their NMR and ECD spectra. Two seco-cucurbitane triterpenes, (24E)-3,4-seco-cucurbita-4,24-diene-3-hydroxy-26,29-dioic acid and (24E)-3,4-seco-cucurbita-4,24-diene-3,26,29-trioic acid, inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), with IC50 values of 20.3 and 0.4μM, respectively. All isolated compounds did not show cytotoxicity against human cancer cell lines, Huh-7 (hepatoma) and EJ-1 (bladder), at 50μM.

Upregulation of PTP1B After Rat Spinal Cord Injury

Protein tyrosine phosphatase 1B (PTP1B), a member of the protein tyrosine phosphatase family, attaches to the endoplasmic reticulum (ER) via its C-terminal tail. Previous studies have reported that PTP1B participates in various signal transduction pathways in many human diseases, including diabetes, cancers, osteoporosis, and obesity. It also plays an important role in the ER stress. ER stress induced by spinal cord injury (SCI) was reported to result in cell apoptosis. Till now, the role of PTP1B in the injury of the central nervous system remains unknown. In the present study, we built an adult rat SCI model to investigate the potential role of PTP1B in SCI. Western blot analysis detected a notable alteration of PTP1B expression after SCI. Immunohistochemistry indicated that PTP1B expressed at a low level in the normal spinal cord and greatly increased after SCI. Double immunofluorescence staining revealed that PTP1B immunoreactivity was predominantly increased in neurons following SCI. In addition, SCI resulted in a significant alteration in the level of active caspase-3, caspase-12, and 153/C/EBP homologous transcription factor protein, which were correlated with the upregulation of PTP1B. Co-localization of PTP1B/active caspase-3 was also detected in neurons. Taken together, our findings elucidated the PTP1B expression in the SCI for the first time. These results suggested that PTP1B might be deeply involved in the injury response and probably played an important role in the neuro-pathological process of SCI.

New sesquiterpenoids from the edible mushroom Pleurotus cystidiosus and their inhibitory activity against α-glucosidase and PTP1B

Nine new sesquiterpenoids, clitocybulol derivatives, clitocybulols G-O (1-9) and three known sesquiterpenoids, clitocybulols C-E (10-12), were isolated from the solid culture of the edible fungus Pleurotus cystidiosus. The structures of compounds 1-12 were determined by spectroscopic methods. The absolute configurations of compounds 1-9 were assigned via the circular dichroism (CD) data analysis. Compounds 1, 6 and 10 showed moderate inhibitory activity against protein tyrosine phosphatase-1B (PTP1B) with IC50 values of 49.5, 38.1 and 36.0μM, respectively.

Identification of Antiviral Agents Targeting Hepatitis B Virus Promoter from Extracts of Indonesian Marine Organisms by a Novel Cell-Based Screening Assay

The current treatments of chronic hepatitis B (CHB) face a limited choice of vaccine, antibody and antiviral agents. The development of additional antiviral agents is still needed for improvement of CHB therapy. In this study, we established a screening system in order to identify compounds inhibiting the core promoter activity of hepatitis B virus (HBV). We prepared 80 extracts of marine organisms from the coral reefs of Indonesia and screened them by using this system. Eventually, two extracts showed high inhibitory activity (>95%) and low cytotoxicity (66% to 77%). Solvent fractionation, column chromatography and NMR analysis revealed that 3,5-dibromo-2-(2,4-dibromophenoxy)-phenol (compound 1) and 3,4,5-tribromo-2-(2,4-dibromophenoxy)-phenol (compound 2), which are classified as polybrominated diphenyl ethers (PBDEs), were identified as anti-HBV agents in the extracts. Compounds 1 and 2 inhibited HBV core promoter activity as well as HBV production from HepG2.2.15.7 cells in a dose-dependent manner. The EC₅₀ values of compounds 1 and 2 were 0.23 and 0.80 µM, respectively, while selectivity indexes of compound 1 and 2 were 18.2 and 12.8, respectively. These results suggest that our cell-based HBV core promoter assay system is useful to determine anti-HBV compounds, and that two PBDE compounds are expected to be candidates of lead compounds for the development of anti-HBV drugs.

Strongylophorines, new protein tyrosine phosphatase 1B inhibitors, from the marine sponge Strongylophora strongilata collected at Iriomote Island

A new meroditerpene, 26-O-ethylstrongylophorine-14 (1), was isolated from the Okinawan marine sponge Strongylophora strongilata together with six known strongylophorines: 26-O-methylstrongylophorine-16 (2) and strongylophorines-2 (3), -3 (4), -8 (5), -15 (6), and -17 (7). The structure of 1 was assigned on the basis of its spectroscopic data. Compound 1 inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with an IC50 value of 8.7 μM, while known compounds 2-8 gave IC50 values of 8.5, >24.4, 9.0, 21.2, 11.9, and 14.8 μM, respectively. Oleanolic acid, a positive control, inhibited PTP1B activity at 0.7 μM (IC50). The inhibitory activities of strongylophorines possessing the acetal moiety at C-26 (1, 2, and 6) were stronger than those of the lactone derivatives (3 and 5). This is the first study to demonstrate that meroditerpenes inhibit PTP1B activity.

Structures and Biological Evaluations of Agelasines Isolated from the Okinawan Marine Sponge Agelas nakamurai

Three new N-methyladenine-containing diterpenes, 2-oxoagelasines A (1) and F (2) and 10-hydro-9-hydroxyagelasine F (3), were isolated from the Okinawan marine sponge Agelas nakamurai Hoshino together with eight known agelasine derivatives, 2-oxoagelasine B (4), agelasines A (5), B (6), D (7), E (8), F (9), and G (10), and ageline B (11). The structures of 1-3 were assigned on the basis of their spectroscopic data and their comparison with those of the literature. Compounds 3 and 5-11 inhibited the growth of Mycobacterium smegmatis with inhibition zones of 10, 14, 15, 18, 14, 20, 12, and 12 mm at 20 μg/disc, respectively. All compounds were inactive (IC50 > 10 μM) against Huh-7 (hepatoma) and EJ-1 (bladder carcinoma) human cancer cell lines. Three 2-oxo derivatives (1, 2, and 4) exhibited markedly reduced biological activity against M. smegmatis. Moreover, compound 10 inhibited protein tyrosine phosphatase 1B (PTP1B) activity with an IC50 value of 15 μM.

Trichoketides A and B, two new protein tyrosine phosphatase 1B inhibitors from the marine-derived fungus Trichoderma sp

Two new octaketides, trichoketides A (1) and B (2), were isolated from a culture broth of the seawater-derived fungus Trichoderma sp. TPU1237 together with two known analogs, trichodermaketones C (3) and D (4), by ODS column chromatography followed by preparative ODS and chiral HPLC. The structures of 1 and 2 were elucidated on the basis of their spectroscopic data, and absolute configurations were assigned by comparing their experimental electronic circular dichroism (ECD) spectra with the calculated ECD spectra. Compounds 1 and 2 were epimers at the C-8 position (α-position of dihydrofuran ring). The IC50 values of compounds 1-4 against protein tyrosine phosphatase 1B were 53.1, 65.1, 68.0 and 55.9 μM, respectively.

Natural and semisynthetic protein tyrosine phosphatase 1B (PTP1B) inhibitors as anti-diabetic agents

Natural products offered more opportunities to develop new drugs and leading compounds as potent PTP1B inhibitors for treating T2DM.

New hippolide derivatives with protein tyrosine phosphatase 1B inhibitory activity from the marine sponge Hippospongia lachne

Five new sesterterpenoids, compounds 1–5, have been isolated from the sponge Hippospongia lachne off Yongxing Island in the South China Sea. The structures of compounds 1–5 were elucidated through extensive spectroscopic analysis, including HRMS, 1D, and 2D NMR experiments. The stereochemistry, including absolute configurations of these compounds, was determined by spectroscopic, chemical, and computational methods. Compounds 1 and 5 showed moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activities with IC₅₀ values of 5.2 μM and 8.7 μM, respectively, more potent than previously reported hippolides.

Marine invertebrate natural products for anti-inflammatory and chronic diseases

The marine environment represents a relatively available source of functional ingredients that can be applied to various aspects of food processing, storage, and fortification. Moreover, numerous marine invertebrates based compounds have biological activities and also interfere with the pathogenesis of diseases. Isolated compounds from marine invertebrates have been shown to pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immunodeficiency syndrome (AIDS), osteoporosis, and so forth. Extensive research within the last decade has revealed that most chronic illnesses such as cancer, neurological diseases, diabetes, and autoimmune diseases exhibit dysregulation of multiple cell signaling pathways that have been linked to inflammation. On the basis of their bioactive properties, this review focuses on the potential use of marine invertebrate derived compounds on anti-inflammatory and some chronic diseases such as cardiovascular disease, osteoporosis, diabetes, HIV, and cancer.