Screening of antiangiogenic potential of twenty two marine invertebrate extracts of phylum Mollusca from South East Coast of India

The Chick Embryo and Its Structures as a Model System for Experimental Ophthalmology

The possibilities of using the chick embryo and its individual structures as a model system in experimental ophthalmology are considered. Cultures of the retina and spinal ganglia from chick embryos are used in the development of new methods for the treatment of glaucomatous optic neuropathy and ischemic optic neuropathy. The chorioallantoic membrane is used for modelling vascular pathologies of the eye, screening of anti-VEGF drugs, and assessing biocompatibility of implants. Co-culturing of chick embryo nervous tissue and human corneal cells makes it possible to study the processes of corneal reinnervation. The use of chick embryo cells and tissues in the "organ-on-a-chip" system opens up wide opportunities for fundamental and applied ophthalmological studies.

Diversity and Biotechnological Potential of Marine Actinomycetes from India

Actinomycetes are potential antibiotic producers that have been isolated from various terrestrial ecosystems and are exploited for their bioactive compounds. On the contrary, the marine environments were less explored and the research on marine actinomycetes had gained momentum only for the past three decades. Marine actinomycetes are one of the most significant producers of diverse groups of secondary metabolites and provide a huge scope for pharmaceutical and other industries. These organisms are proved to be important, both biotechnologically and economically considering their global presence. The marine ecosystem in India is less explored for the isolation of actinomycetes and several ecological niches are left unattended. Compared to the global scenario, the contribution from Indian researchers towards the isolation and exploitation of marine actinomycetes from the Indian sub-continent is noteworthy. Exploration of actinomycetes from these ecosystems will certainly yield new species and metabolites. Considering the declining rate of drug discovery from terrestrial actinomycetes, the marine counterparts, especially from unexplored regions from the Indian coast will hold a promising way ahead. Apart from drugs, these organisms are reported for the production of different industrially important enzymes like cellulase, amylase, protease, lipase, etc. They are also used in environmental applications, agriculture, and aquacultures sectors. With the rapid advancement in the study of actinomycetes from different marine sources in India, new metabolites are being discovered which have an important role from the economic and industrial point of view. As the world is witnessing newer diseases such as Sars-Cov 2 and the pandemic due to its demands drugs and other metabolites are increasing day by day. Therefore, the necessity for the quest for unique and rare marine actinomycetes is enhancing too. This review highlights the research on marine actinomycetes in India and also the challenges associated with its research.

Ethnopharmacological evaluation of antioxidant, anti-angiogenic, and anti-inflammatory activity of some traditional medicinal plants used for treatment of cancer in Togo/Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Cancer is a multistep disease and its management is exceedingly expensive. Nowadays medicinal plants are gaining more attention in drug discovery and approximately 70% of anticancer drugs were developed from natural products or plants. A strong candidate from medicinal plant with anticancer potential should have four major properties: antioxidant, anti-inflammatory, anti-angiogenic, and cytotoxic activities.

AIM OF THE STUDY

In order to assess Togolese traditional healer's claims about the anticancer potential of medicinal plants and obtain candidate plants for anticancer drug discovery, some species were selected from surveys and evaluated for their antioxidant, anti-inflammatory, anti-angiogenic and cytotoxic activities.

METHODS

Four species, Cochlospermum planchonii (CP), Piliostigma thonningii (PT), Paullinia pinnata (PP), and Securidaca longipedunculata (SL) were selected and analyzed to detect the phytochemical components. The mentioned bioactivities were evaluated using in vitro, ex vivo and in vivo assays.

RESULTS

Relative to SL extract, CP and PT have shown significantly high polyphenols and flavonoids content. The DPPH, FRAP, and TAC of the extracts revealed that CP, PT, and PP have a potent antioxidant effect compared to SL. MDA analysis revealed the same antioxidant activity as CP, PT and PP showed a minor MDA level. The egg albumin denaturation assay showed that IC50 of CP and PP was significantly higher than control (P < 0.05). In contrast, the Bovine Serum Albumin (BSA) results showed a nonsignificant effect (P > 0.05). Notably, SL extract was nonsignificant to control in both Egg Albumin and BSA. Furthermore, angiogenesis assay showed that SL at 50 μg/ml and PP at 100 μg/ml effectively reduced the number of blood vessels than control and showed a potent anti-angiogenic effect (2.7-fold and 2.5-fold, respectively, P < 0.05). No cytotoxicity on PBMC was reported for CP, PP, and PT up to 1000 μg/ml, whereas SL at 1000 μg/ml exhibit benign cytotoxicity (P < 0.0001).

CONCLUSION

This study provided in vitro evidence supporting further evaluation on cancer cell lines and tumors in vivo.

Anti-angiogenic activity of chloride and potassium channel modulators: repurposing ion channel modulators

Background

Excessive angiogenesis can be the root cause of many pathological conditions. Various types of ion channels are found on the endothelial cells. These ion channels play a vital role in the multi-stepped process of angiogenesis. The study aims to investigate the anti-angiogenic effects of specific ion channel modulators mefloquine (volume-regulated chloride channel blocker), lubiprostone (ClC-2 channel agonist), and 4-aminopyridine (voltage-gated potassium channel blocker).

Results

The anti-angiogenic activity of ion channel modulators was screened by measuring its effects on the area of neovascularization and histopathological studies by in vivo (corneal neovascularization) method and by in vitro assays, endothelial cell proliferation assay, cell migration assay, and matrigel cord-like morphogenesis assay. The test and standard drug (bevacizumab) groups were compared with the control group using one-way ANOVA, followed by post hoc test, and Dunnett’s test to compare the mean of all the groups with the control mean. The results revealed that mefloquine at the dose of 0.6% w/v and 1.0% w/v, lubiprostone at the dose of 0.5% w/v and 1.0% w/v, and 4-aminopyridine at the dose of 2% w/v and 4% w/v showed significant anti-angiogenic property. In the studies on human umbilical vein endothelial cells, the test drugs (100 nM) showed significant inhibition of proliferation, migration, and decrease in network length of cord-like tubes.

Conclusion

The scientific findings indicate that the test drugs have potent anti-angiogenic activity by inhibiting the cell proliferation, inhibiting the cell volume increase, arresting the cell cycle progression and by causing membrane hyperpolarization. The potent anti-angiogenic drugs obtained by repurposing these ion channel modulators, in the further studies, will be able to treat the diseases due to excess angiogenesis from the root cause.

Graphical abstract

Methanolic extract of Ephedra ciliata promotes wound healing and arrests inflammatory cascade in vivo through downregulation of TNF-α

Chronic wounds may lead to the development of various pathological conditions such as diabetic foot ulcers and pressure sores. The current study evaluated wound healing and anti-inflammatory potentials of methanolic extract of Ephedra ciliata using series of in vivo models. Methanolic extract of Ephedra ciliata was prepared by maceration (Ec.Me). Qualitative and quantitative (HPLC) phytochemical and metal analyses were conducted to explore the chemical and metal profiles of Ec.Me. Safety profile (behavioural) and, antimicrobial, antioxidant, wound healing, anti-inflammatory and anti-angiogenic potentials of Ec.Me were evaluated using well-established in vitro and in vivo models. ELISA assay was performed to estimate the effects of Ec.Me treatment on serum levels of TNF-α. HPLC analysis identified quercetin as one of the major compounds in Ec.Me. Safety study data showed that Ec.Me was safe up to the dose of 2000 mg/kg. Antimicrobial assay data showed that Ec.Me was active against bacterial (Staphylococcus aureus) as well as fungal (Candida albicans and Aspergillus niger) strains. Ec.Me showed modertate antioxidant potential in in vitro and in vivo models. Data of excision and burn wound healing models showed that Ec.Me, promoted wound closure in a dose and time-dependent manner. Treatment with 20% Ec.Me cream and heparin showed almost the same effects with no statistical differences (p > 0.05). Ec.Me also showed time-dependent anti-inflammatory activities in both acute and chronic models. In carrageenan model, treatment with 200 mg/kg of Ec.Me showed comparable anti-inflammatory effects (p > 0.05) with quercetin and indomethacin throughout the study. In cotton pellet granuloma model treatment with 200 mg/kg of Ec.Me and indomethacin inhibited granuloma formation significantly better (p < 0.05) as compared with the rest of the treatment groups. Histopathological examination of skin samples showed marked improvement in architecture with minimal infiltration of inflammatory cells. Data of in vivo angiogenesis assay showed marked improvement in vessels length, density, branching points, total segments and total nets after treatment with Ec.Me, indicating no toxic effects towards vasculature development. Significant (p < 0.05) downregulation of TNF-α was observed in serum samples of animals treated with Ec.Me. Based on data of the current study, it is concluded that quercetin-rich extract of Ephedra ciliata has wound healing and anti-inflammatory potentials via downregulation of TNF-α. Moreover, it is suggested that the antimicrobial activity of Ec.Me prevented microbial invasion, thus promoted natural wound healing mechanisms as well.

Exploration of 2-deoxy-D-ribose and 17β-Estradiol as alternatives to exogenous VEGF to promote angiogenesis in tissue-engineered constructs

Aim: In this study, we explored the angiogenic potential and proangiogenic concentration ranges of 2-deoxy-D-ribose (2dDR) and 17β-Estradiol (E2) in comparison with VEGF. The 2dDR and E2 were then loaded into tissue engineering (TE) scaffolds to investigate their proangiogenic potential when released from fibers. Materials & methods: Ex ovo chick chorioallantoic membrane (CAM) assay was used to evaluate angiogenic activity of 2dDR and E2. Both factors were then introduced into scaffolds via electrospinning to assess their angiogenic potential when released from fibers. Results: Both factors were approximately 80% as potent as VEGF and showed a dose-dependent angiogenic response. The sustained release of both agents from the scaffolds stimulated neovascularization over 7 days in the chorioallantoic membrane assay. Conclusion: We conclude that both 2dDR and E2 provide attractive alternatives to VEGF for the functionalization of tissue engineering scaffolds to promote angiogenesis in vivo.

Methanolic extract of Euchelus asper exhibits in-ovo anti-angiogenic and in vitro anti-proliferative activities

Background

The marine environment is a rich source of bioactive natural products. Many of the marine bioactive compounds have been derived successfully from molluscs. Euchelus asper is a marine mollusc which is commonly found in the intertidal rocky regions of the Mumbai coast. The present study was focused on evaluating the anti-angiogenic and anti- proliferative activities of methanolic extract of Euchelus asper (EAME).

Methods

The anti-angiogenic activity of EAME (50–800 μg/mL) was assessed by chick chorio-allantoic membrane (CAM) model wherein multiple parameters in the CAM blood vessels were analysed through morphometric and histological investigations. In vitro testing of EAME (5–20 μg/mL) included its cytotoxicity against three different cancer cell lines, its effect on cell proliferation by wound healing assay as well as their relevant molecular mechanisms. Statistical analysis was carried out by two-tailed student’s t test for two unpaired groups.

Results

Analysis of CAM revealed that the extract is effective in reducing the branching points of the 1st order blood vessels or capillaries of CAM. Histological analysis of CAM showed significant decrease in capillary plexus and compartmentalization along with increase in mesodermal blood vessels, thus establishing its anti-angiogenicity. Further, EAME exhibited moderate but significant cytotoxicity against A549 non-small cell lung carcinoma cell line. We also demonstrated that the cytotoxicity of EAME in A549 was associated with its apoptotic activity by subG1 phase arrest. Lastly, EAME significantly reduced A549 proliferation by reducing the expression of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9).

Conclusion

Overall, our study suggested that EAME has potential to inhibit tumour angiogenic and proliferative activity and may be a potential source for development of new anti-cancer pharmaceuticals.