Inhibition of MMP2-PEX by a novel ester of dihydroxy cinnamic and linoleic acid from the seagrass Cymodocea serrulata

Matrix metalloproteinases (MMPs) are pivotal for cancer cell migration and metastasis which are generally over-expressed in such cell types. Many drugs targeting MMPs do so by binding to the conserved catalytic domains and thus exhibit poor selectivity due to domain-similarities with other proteases. We report herein the binding of a novel compound [3-(E-3,4-dihydroxycinnamaoyloxyl)-2-hydroxypropyl 9Z, 12Z-octadeca-9, 12-dienoate; Mol. wt: 516.67 Da], (C₁), isolated from a seagrass, Cymodocea serrulata to the unconserved hemopexin-like (PEX) domain of MMP2 (- 9.258 kcal/mol). MD simulations for 25 ns, suggest stable ligand-target binding. In addition, C₁ killed an ovarian cancer cell line, PA1 at IC₅₀: 5.8 μM (lesser than Doxorubicin: 8.6 µM) and formed micronuclei, apoptotic bodies and nucleoplasmic bridges whilst causing DNA laddering, S and G2/M phase dual arrests and MMP disturbance, suggesting intrinsic apoptosis. The molecule increased mRNA transcripts of BAX and BAD and down-regulated cell survival genes, Bcl-xL, Bcl-2, MMP2 and MMP9. The chemical and structural details of C₁ were deduced through FT-IR, GC-MS, ESI-MS, ¹H and ¹³C NMR [both 1D and 2D] spectra.

Dalspinin isolated from Spermacoce hispida (Linn.) protects H9c2 cardiomyocytes from hypoxic injury by modulating oxidative stress and apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Spermacoce hispida (S.hispida), a potential medicinal plant has been traditionally used as an antibacterial, antieczemic, antihypertensive, antidiabetic and antihyperlipidemic agent. Although, this plant has been claimed to protect against oxidative injury and inflammatory conditions in recent studies, its cardioprotective effect and the active constituents responsible for its bioactivity is sparsely studied. Hence this work is undertaken to study the active biomolecule responsible for modulating the cardiomyocytes on hypoxic injury relevant to its ethanopharmacology.

AIM OF THE STUDY

The current study is to isolate and characterize a bioactive molecule from S.hispida, which exhibits protection against hypoxic injury in an in vitro hypoxic model of cultured H9c2 cardiomyocytes.

MATERIALS AND METHODS

The methanolic extract of S.hispida plant was fractionated with various solvents sequentially. The ethyl acetate fraction that was concentrated and chromatographed over silica gel column eluted 18 fractions, which yielded 5 compounds, which were characterized using spectral data. The isolated new compound was further tested for its protective effect against hypoxic injury, wherein cobalt chloride (CoCl₂) was used to induce hypoxia in H9c2 cardiomyoblasts. To evaluate the protective effect of the isolated compound, the markers of oxidative stress, apoptosis, and cell death were checked by endogenous levels of antioxidants, [malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione (GSH)], lactate dehydrogenase (LDH) activity and immunoblot (HIF-α, Bcl2, Bax, procaspase and cleaved caspase-3).

RESULTS

Among the five compounds isolated and characterized from S. hispida methanolic extract, β-sitosterol, ursolic acid, quercetin and rutin were known phytochemicals, while the new isoflavone was identified as dalspinin-7-0-β-D-galactopyranoside (DBG). Among the isolated compounds, the antioxidant potential of DBG confirmed by DPPH free radical scavenging and ORAC assays was superior. CoCl₂-induced hypoxic condition significantly decreased cell viability, SOD activity, GSH concentration and increased the level of MDA and LDH activity. Western blot studies revealed an upregulation of HIF-1α, Bax and caspase and down regulation of Bcl-2 expression. The oxidative abnormalities were ameliorated by DBG pretreatment, as deduced by the reduced CoCl₂-induced cytotoxicity, MDA concentration, LDH activity and the expression of HIF-1α, Bax and caspase and the enhanced levels of SOD, GSH and Bcl2 expression in a dose-dependent manner.

CONCLUSION

DBG protects H9c2 cells from CoCl₂-induced hypoxic damage by mitigating oxidative stress and preserving cell viability. The overall findings highlight the protective action of DBG, a potential source of antioxidant of natural origin against hypoxic injury and may help in mitigating the progress of oxidative stress in cardiac cell death.

A natural anticancer pigment,Pheophytin a,from a seagrass acts as a high affinity human mitochondrial translocator protein (TSPO) ligand, in silico, to reduce mitochondrial membrane Potential (∆ψmit) in adenocarcinomic A549 cells

BACKGROUND

The present investigation looks at the most likely possibilities of usage of a naturally occurring photosynthetic pigment, Pheophytin a, from the seagrass, Syringodium isoetifolium, for plausible use as human TSPO ligand.

METHODS

Pheophytin a isolated in our laboratory previously was administered to A549 cell lines in vitro to examine its effects on cell migrations, DNA, cell cycle, Mitochondrial Membrane Potential and gene expressions. In silico tools were used to predict the nature of the compound and target binding.

RESULTS

Pheophytin a hadIC₅₀ values of 22.9 ± 5.8 µM for cancerous A549 cell lines, whilst not targeting non-cancerous vero cells [IC₅₀: 183.6 ± 1.92 µM]. Pheophytin a hindered cellular migration, fragmented DNA, arrested cell cycle precisely at S phase, reduced ∆ψ_mit and directed mRNA expressions toward apoptosis. In silico tools indicate that the compound binds to TSPO with high effectiveness to collapse ∆ψ_mit(which is proved using wet lab experiments) to promote mitophagy.

CONCLUSION

Hence Pheophytin a could be seen as a possible TSPO ligand for targeting metastatic alveolar cancers like A549 via intrinsic apoptotic pathway.

GENERAL SIGNIFICANCE

Given the inherent non-toxic nature of the compound and easy extractability from almost all autotrophic eukaryotes, one could be confident to testing in animal models.

Bioassay guided fractionation and identification of active anti-inflammatory constituent from Delonix elata flowers using RAW 264.7 cells

CONTEXT

Delonix elata (L.) Gamble (Fabaceae) has been used in the Indian traditional medicine system to treat rheumatism and inflammation.

AIM

To assess the anti-inflammatory effect of Delonix elata flowers and to isolate the active principle.

MATERIALS AND METHODS

The prompt anti-inflammatory constituent was isolated from Delonix elata flower extracts using bioassay guided fractionation in liposaccharide (LPS) stimulated RAW 264.7 macrophage cell line. The anti-inflammatory activity of extracts/fractions/sub-fractions/compounds (10, 25, and 50 µg/ml) was evaluated by estimating the levels of nitric oxide (NO), TNF-α, and IL-1β after 24 h of LPS induction (1 μg/ml). The isolated active compound was subjected to NMR, IR, and UV analyses for structure determination.

RESULTS

In an attempt to search for anti-inflammatory constituents, the active pure principle was isolated and crystallized as a white compound from Delonix elata flowers methanol extract. This active compound (50 µg/ml) decreased the release of inflammatory mediators levels such as NO (0.263 ± 0.03 µM), TNFα (160.20 ± 17.57 pg/ml), and IL-1β (285.79 ± 15.16 pg/ml) significantly (p < 0.05); when compared to the levels of NO (0.774 ± 0.08 µM), TNFα (501.71 ± 25.14 pg/ml), and IL-1β (712.68 ± 52.25 pg/ml) from LPS-stimulated macrophage cells. The active compound was confirmed as hesperidin with NMR, IR, and UV spectroscopy data. This is the first report of this compound from Delonix elata flowers.

CONCLUSION

The findings of the study support the traditional use of Delonix elata flowers to treat inflammation.

Spectroscopic investigations, antimicrobial, and cytotoxic activity of green synthesized gold nanoparticles

The gold nanoparticles (AuNPs) were synthesized by using naturally available Punica Granatum fruit extract as reducing and stabilizing agent. The biosynthesized AuNPs was characterized by using UV-Vis, fluorescence, high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric (TGA) analysis. The surface plasmon resonance (SPR) band at 585nm confirmed the reduction of auric chloride to AuNPs. The crystalline nature of the biosynthesized AuNPs was confirmed from the HRTEM images, XRD and selected area electron diffraction (SAED) pattern. The HRTEM images showed the mixture of triangular and spherical-like AuNPs having size between 5 and 20nm. The weight loss of the AuNPs was measured by TGA as a function of temperature under a controlled atmosphere. The biomolecules are responsible for the reduction of AuCl4(-) ions and the formation of stable AuNPs which was confirmed by FTIR measurement. The synthesized AuNPs showed an excellent antibacterial activity against Candida albicans (ATCC 90028), Aspergillus flavus (ATCC 10124), Staphylococcus aureus (ATCC 25175), Salmonella typhi (ATCC 14028) and Vibrio cholerae (ATCC 14033). The minimum inhibitory concentration (MIC) of AuNPs was recorded against various microorganisms. Further, the synthesized AuNPs shows an excellent cytotoxic result against HeLa cancer cell lines at different concentrations.