Multi-Target Antibacterial Mechanism of Moringin From Moringa oleifera Seeds Against Listeria monocytogenes

Moringin [4-(α-L-rhamnosyloxy) benzyl isothiocyanate] is an isothiocyanate from Moringa oleifera seeds. It is the bioactivated form of the glucosinolate precursor glucomoringin with various health benefits. However, few studies have examined the antibacterial activity of moringin. This study aimed to investigate the antimicrobial activity and mechanism of moringin against Listeria monocytogenes. The minimum inhibitory concentration (MIC), and growth curves were used to evaluate the bacteriostatic effect of moringin against L. monocytogenes. Transcriptome analysis by RNA sequencing was performed to elucidate the underlying mechanism of moringin against L. monocytogenes. The transcriptome results were validated. The results showed that moringin inhibited the growth of L. monocytogenes with a MIC of 400 μM. RNA sequencing results showed that the differences in the expression of genes related to the cell wall and membrane biosynthesis, phosphotransferase system (PTS), oxidative stress, energy metabolism, and DNA binding were significantly affected. As with the transcriptome results, the results of the mechanism verification found that moringin damaged the integrity of the cell wall and cell membrane, stimulated oxidative stress, interfered with energy metabolism and DNA replication, and finally led to the death of L. monocytogenes. The present study provides evidence that moringin exhibits strong antimicrobial activity against L. monocytogenes and insight into its potential mechanism.

Phytochemical Analyses, Antioxidant and Anticancer Activities of Ethanolic Leaf Extracts of Moringa oleifera Lam. Varieties

Moringa oleifera Lam. (Moringaceae) is revered as s 'miracle tree' due to its remarkable nutritional, medicinal and industrial uses. In our study, a comparative analysis of the nutritional parameters (antioxidant activity, sugar content-TSS, total soluble proteins-TSP and mineral contents), phytochemicals (HPLC analysis of four anticancer compounds), and cytotoxicity of M. oleifera leaf extracts (MLEs) of five selected varieties (conventional, PKM-1, PKM-2, ODC, and Jaffna), was performed. Jaffna variety possessed the highest antioxidant activity (FRAP) followed by other four varieties. The trend observed was: Jaffna (9.47 µg/mL, 18.48 µg/mL, 29.39 µg/mL, and 35.37 µg/mL) > PKM-1 (4.82 µg/mL, 7.63 µg/mL, 22.33 µg/mL, and 27.71 µg/mL) > PKM-2 (2.10 µg/mL, 7.04 µg/mL, 13.18 µg/mL, and 21.78 µg/mL) > ODC (0.17 µg/mL, 2.10 µg/mL, 4.41 µg/mL and 13.94 µg/mL) > Conventional (0.05 µg/mL, 1.08 µg/mL, 2.86 µg/mL, and 5.40 µg/mL), total soluble proteins (TSP) [0.69 ± 0.01 and 0.94 ± 0.01 µg/mL (young and mature stage, respectively)], sugar content (TSS) [0.39 ± 0.01 and 0.51 ± 0.01 µg/mL (young and mature stage, respectively)], chlorophyll content [1.07 ± 0.01 (plantlet stage), 1.36 ± 0.003 (vegetative-stage), 0.82 ± 0.004 (reproductive stage) mg/g], followed by the other four varieties. The trend observed for cytotoxic activities of ethanolic MLEs on HepG2 cell line, based on the IC50 values, was conventional (1.22 mg/mL) > ODC (0.90 mg/mL) > PKM-2 (0.65 mg/mL) > PKM-1 (0.35 mg/mL) > Jaffna (0.15 mg/mL). The results of HPLC quantification of anticancer compounds [beta-sitosterol (0.244%), quercetin (0.216%), kaempferol (0.013%), and moringin (0.063%)] was also in consonance with that of MTT assay. In summary, the trend observed in all the parameters tested was Jaffna > PKM-1 > PKM-2 > ODC > conventional. Thus, Jaffna variety has a better potential to combat malnutrition and cancer and must be recommended for commercial plantations.

Moringin and Its Structural Analogues as Slow H2S Donors: Their Mechanisms and Bioactivity

Moringin (rhamnobenzyl isothiocyanate) is a major bioactive compound in moringa seeds, which have been used as a healthy food. However, its bioactivity mechanisms are not well understood. We investigated moringin and its structurally similar analogues, including benzyl isothiocyanate and 4-hydroxylbenzyl isothiocyanate, for their hydrogen sulfide (H₂S)-releasing activity triggered by cysteine. These isothiocyanates rapidly formed cysteine adducts, which underwent intramolecular cyclization followed by slowly releasing (a) organic amine and raphanusamic acid and (b) H₂S and 2-carbylamino-4,5-dihydrothiazole-4-carboxylic acids. The product distributions are highly dependent on para-substituents on the phenyl group. Moringin has higher cytotoxicity to cancer cells and is a more potent anti-inflammatory agent than benzyl and hydroxybenzyl analogues, while benzyl isothiocyanate is a better antibacterial agent. Taken together, their bioactivity may not be directly related to their H₂S donation activity. However, other metabolites alone do not have cytotoxicity and anti-inflammatory activity. These findings indicated that their activity may be the combination effects of different metabolites via competitive pathways as well the para-substituent groups of benzyl ITCs.

Moringin, A Stable Isothiocyanate from Moringa oleifera, Activates the Somatosensory and Pain Receptor TRPA1 Channel In Vitro

Moringa oleifera Lam. is a tropical plant widely used in traditional medicines and as a food supplement. It is characterized by the presence of glucosinolates and isothiocyanates; the stable isothiocyanate 4-[(α-l-rhamnosyloxy)benzyl]isothiocyanate (moringin) has been widely studied for its bioactivity as hypoglycemic, antimicrobial, anticancer and in particular for its involvement in nociception and neurogenic pain. Moringa extracts and pure moringin were submitted to in vitro assays with the somatosensory TRPA1 ion channel, proving that moringin is a potent and effective agonist of this receptor involved in nociceptive function and pain states. Moringin do not activate or activates very weakly the vanilloids somatosensory channels TRPV1,2,3 and 4, and the melastatin cooling receptor TRPM8. The comparison of moringin’s activity with other known agonists of natural origin is also discussed.

Moringin Pretreatment Inhibits the Expression of Genes Involved in Mitophagy in the Stem Cell of the Human Periodontal Ligament

Moringin [4-(α-L-rhamnosyloxy) benzyl isothiocyanate] is an isothiocyanate extracted from Moringa oleifera seeds. It is an antioxidant known for several biological properties useful in the treatment of neurodegenerative diseases. Several neurodegenerative disorders such as Parkinson’s and Alzheimer’s diseases are linked to dysfunctional mitochondria due to the resulting increase of Reactive Oxygen Species (ROS). Stem cell-based therapeutic treatments in neurodegenerative diseases provide an alternative strategy aimed to replace the impaired tissue. In this study were investigated the deregulated genes involved in mitophagy in the human periodontal ligament stem cells pretreated with moringin. The RNA-seq study reveals the downregulation of PINK1, with a fold change (FC) of −0.56, such as the genes involved in the phagophore formation (MAP1LC3B FC: −0.73, GABARAP FC: −0.52, GABARAPL1 FC: −0.70, GABARAPL2 FC: −0.39). The moringin pretreatment downregulates the pro−apoptotic gene BAX (−0.66) and upregulates the anti-apoptotic genes BCL2L12 (FC: 1.35) and MCL1 (FC: 0.36). The downregulation of the most of the caspases (CASP1 FC: −1.43, CASP4 FC: −0.18, CASP6 FC: −1.34, CASP7 FC: −0.46, CASP8 FC: −0.65) implies the inactivation of the apoptotic process. Our results suggest that mitochondrial dysfunctions induced by oxidative stress can be inhibited by moringin pretreatment in human periodontal ligament stem cells (hPDLSCs).

A Strategy to Deliver Precise Oral Doses of the Glucosinolates or Isothiocyanates from Moringa oleifera Leaves for Use in Clinical Studies

The tropical tree Moringa oleifera produces high yields of protein-rich leaf biomass, is widely used as a food source, contains an abundance of phytochemicals, and thus has great potential for chronic disease prevention and perhaps, treatment. We have developed and characterized standardized ways of preparing aqueous “teas” from moringa leaves to deliver precisely calibrated levels of phytochemicals for use in clinical trials. These phytochemicals, especially the glucosinolate glucomoringin and the isothiocyanate moringin, produced from it following hydrolysis by the enzyme myrosinase, provide potent anti-inflammatory and cytoprotective indirect antioxidant activity. The taste of both hot and cold teas is palatable without the need for flavor masking. These teas can be easily and reproducibly prepared in underserved tropical regions of the world where moringa is cultivated. Isothiocyanate yield from a cold extraction was rapid and essentially complete after 30 min and its anti-inflammatory potential is comparable to that of equimolar purified moringin. A preparation similar to this may be safe to consume with respect to its bacterial titer even after 48 h without refrigeration. Thus, facile delivery of moringa tea to both adults and children for clinical evaluation of their effects on such conditions as autism, diabetes, and hypertension, is now possible.

Human gingival mesenchymal stem cells pretreated with vesicular moringin nanostructures as a new therapeutic approach in a mouse model of spinal cord injury

Spinal cord injury (SCI) is a neurological disorder that arises from a primary acute mechanical lesion, followed by a pathophysiological cascade of events that leads to further spinal cord tissue damage. Several preclinical and clinical studies have highlighted the ability of stem cell therapy to improve long-term functional recovery in SCI. Previously, we demonstrated that moringin (MOR) treatment accelerates the differentiation process in mesenchymal stem cells inducing an early up-regulation of neural development associated genes. In the present study, we investigated the anti-inflammatory, anti-apoptotic, and regenerative effects of gingival mesenchymal stem cells (GMSCs) pretreated with nanostructured liposomes enriched with MOR in an animal model of SCI. SCI was produced by extradural compression of the spinal cord at levels T6-T7 in ICR (CD-1) mice. Animals were randomly assigned to the following groups: Sham, SCI, SCI + GMSCs (1 × 106  cell/i.v.), SCI + MOR-GMSCs (1 × 106  cell/i.v.). Our data show that MOR-treated GMSCs exert anti-inflammatory and anti-apoptotic activities. In particular, MOR-treated GMSCs are able to reduce the spinal cord levels of COX-2, GFAP, and inflammatory cytokines IL-1β and IL-6 and to restore spinal cord normal morphology. Also, MOR-treated GMSCs influenced the apoptotic pathway, by reducing Bax, caspase 3, and caspase 9 expressions.

Moringin from Moringa Oleifera Seeds Inhibits Growth, Arrests Cell-Cycle, and Induces Apoptosis of SH-SY5Y Human Neuroblastoma Cells through the Modulation of NF-κB and Apoptotic Related Factors

In the last decades, glucosinolates (GLs), precursors of isothiocyanates (ITCs), have been studied mostly for their chemopreventive and chemotherapeutic properties. The aim of our research was to study the antiproliferative effect of 4-(α-L-rhamnopyranosyloxy) benzyl glucosinolate (glucomoringin; GMG) bioactivated by myrosinase enzyme to form the corresponding isothiocyanate 4-(α-L-rhamnopyranosyloxy) benzyl C (moringin) in SH-SY5Y human neuroblastoma cells. We found that moringin significantly reduced SH-SY5Y cell growth in a time and concentration-dependent (p < 0.05, 0.01, and 0.001 vs. ctrl, after treatment with 16.4 µM moringin for 24, 48, and 72 h, respectively) manner through a mechanism involving the activation of apoptotic machinery. In addition, it altered the normal progression of cells through the cell cycle, increasing the cell population in both G2 and S phases, as well as decreasing that in the G1 phase. Studying the drug mechanism of action, we found that moringin was able to increase the expression of p53, p21, and Bax at both the protein and transcriptional level. Moreover, exposure of SH-SY5Y cells to moringin significantly increased the gene expression of both caspase 3 and 9 and enhanced their cleavage, thereby initiating an intrinsic apoptotic cascade. Finally, moringin inhibited nuclear translocation of NF-κB. Our study demonstrates the ability of moringin to reduce the growth of SH-SY5Y cells and reveals its mechanism of action, suggesting its promising role as an anticancer drug.

The α-Cyclodextrin/Moringin Complex: A New Promising Antimicrobial Agent against Staphylococcus aureus

Antimicrobial resistance is one of the major clinical concerns, making the discovery of new antimicrobial drugs desirable. Moringin (MOR), the major isothiocyanate produced from Moringa oleifera seeds, could represent an alternative therapeutic strategy to commonly used antibiotics. The aim of our study was to investigate the antimicrobial effect of MOR conjugated with α-cyclodextrin (MOR/α-CD), a complex with an improved solubility and stability in aqueous solutions. Our data demonstrated that MOR/α-CD was able to exert antimicrobial activity against the S. aureus reference strains (ATCC 25923, ATCC 6538, and ATCC BAA-977). Moreover, MOR/α-CD showed bacteriostatic effects (MIC = minimum inhibitory concentration = 0.5 mg/mL) and bactericidal properties (MBC = minimum bactericidal concentration = 1 mg/mL) against the overall assessed strains. In addition, MOR/α-CD showed bactericidal activity against the S. aureus strain ATCC BAA-977 after treatment with erythromycin (Ery), which induced clindamycin-resistance on the erm (A) gene. This evidence led us to assume that MOR/α-CD could be a promising antimicrobial agent against strains with the clindamycin-resistant phenotype (CC-resistant).

A Combined Approach of NMR and Mass Spectrometry Techniques Applied to the α-Cyclodextrin/Moringin Complex for a Novel Bioactive Formulation †

Moringin, obtained via enzymatic conversion of the glucosinolate precursor glucomoringin, is an uncommon member of the isothiocyanate class, and has been proven to possess a broad range of biological activities such as antitumor activity, protection against neurodegenerative disorders and bactericidal effects. Since moringin is weakly soluble in water and unstable in aqueous medium, cyclodextrins (CDs) were considered for the development of a new moringin formulation, with a view to improving its solubility and stability in aqueous solution for use as an anti-inflammatory. A combined structural study using proton nuclear magnetic resonance (¹H-NMR), diffusion-ordered spectroscopy (DOSY) and ion mobility mass spectrometry (IM-MS) is reported, highlighting the formation of a 1:1 α-CD/moringin inclusion complex. The association constant K was determined (1300 M-1 at 300 K). Completion of the structural characterization was performed by T-ROESY and MS/MS experiments, which evidenced the mode of penetration of moringin into α-CD. Finally, the "chaperone-like" properties of α-CD with respect to the stability of moringin have been highlighted.

Moringin activates Wnt canonical pathway by inhibiting GSK3β in a mouse model of experimental autoimmune encephalomyelitis

Aberrant canonical Wnt-β-catenin signaling has been reported in multiple sclerosis (MS), although the results are controversial. The present study aimed to examine the role of the Wnt-β-catenin pathway in experimental MS and also to test moringin (4-[α-L-rhamnopyranosyloxy]-benzyl isothiocyanate), resulting from exogenous myrosinase hydrolysis of the natural phytochemical glucomoringin 4(α-L-rhamnosyloxy)-benzyl glucosinolate as a modulator of neuroinflammation via the β-catenin-PPARγ axis. Experimental autoimmune encephalomyelitis (EAE), the most common model of MS, was induced in C57BL/6 mice by immunization with MOG35-55. Released moringin (10 mg/kg glucomoringin +5 μL myrosinase/mouse) was administered daily for 1 week before EAE induction and continued until mice were killed on day 28 after EAE induction. Our results clearly showed that the Wnt-β-catenin pathway was downregulated in the EAE model, whereas moringin pretreatment was able to avert this. Moringin pretreatment normalizes the aberrant Wnt-β-catenin pathway, resulting in GSK3β inhibition and β-catenin upregulation, which regulates T-cell activation (CD4 and FoxP3), suppresses the main inflammatory mediators (IL-1β, IL-6, and COX2), through activation of PPARγ. In addition, moringin attenuates apoptosis by reducing the expression of the Fas ligand and cleaved caspase 9, and in parallel increases antioxidant Nrf2 expression in EAE mice. Taken together, our results provide an interesting discovery in identifying moringin as a modulator of the Wnt-β-catenin signaling cascade and as a new potential therapeutic target for MS treatment.