Gina Rosalinda De Nicola

Intact glucosinolates modulate hepatic cytochrome P450 and phase II conjugation activities and may contribute directly to the chemopreventive activity of cruciferous vegetables

The currently accepted view is that the chemopreventive activity of glucosinolates is exclusively mediated by their degradation products, such as isothiocyanates. In the present study, evidence is presented for the first time that intact glucosinolates can modulate carcinogen-metabolising enzyme systems. The glucosinolates glucoraphanin and glucoerucin were isolated from cruciferous vegetables and incubated with precision-cut rat liver slices. Both glucosinolates elevated the O-dealkylations of methoxy- and ethoxyresorufin, markers for CYP1 activity; supplementation of the incubation medium with myrosinase, the enzyme that converts glucosinolates to their corresponding isothiocyanates, abolished these effects. Moreover, both glucoerucin and glucoraphanin increased the apoprotein levels of microsomal CYP1A1, CYP1A2 and CYP1B1. At higher concentrations, both glucosinolates enhanced quinone reductase activity, whereas glucoraphanin also elevated glutathione S-transferase; in this instance, however, supplementation of the incubation medium with myrosinase exacerbated the inductive effect. Finally, both glucosinolates increased modestly cytosolic quinone reductase, GSTα and GSTμ protein levels, which became more pronounced when myrosinase was added to the incubations with the glucosinolate. It may be inferred that intact glucosinolates can modulate the activity of hepatic carcinogen-metabolising enzyme systems and this is likely to impact on the chemopreventive activity linked to cruciferous vegetable consumption.

Up-regulation of cytochrome P450 and phase II enzyme systems in rat precision-cut rat lung slices by the intact glucosinolates, glucoraphanin and glucoerucin

It is believed that the chemopreventive activity of cruciferous vegetables in the lung and other tissues is exclusively the result of exposure to degradation products of glucosinolates, such as the isothiocyanates, and that the parent glucosinolates make no contribution. In the present study, evidence is presented for the first time that, in rat lung, the intact glucosinolates, glucoraphanin and glucoerucin, can modulate carcinogen-metabolising enzyme systems. The glucosinolates were isolated from cruciferous vegetables and incubated (1-25 μM) with precision-cut rat lung slices for 24h. Both glucosinolates, at concentrations as low as 1 μM, up-regulated the O-deethylation of ethoxyresorufin and the apoprotein levels of CYP1A1 and CYP1B1; supplementation of the incubation medium with myrosinase, the enzyme that converts glucosinolates to their corresponding isothiocyanates, abolished the rise in ethoxyresorufin O-deethylase activity. In contrast, neither glucosinolate, at the concentrations studied, influenced quinone reductase activity in the lung slices, but addition of myrosinase to the glucosinolate incubations led to a marked rise in activity. Glutathione S-transferase activity, monitored using 1-chloro-2,4-dinitrobenzene as the accepting substrate, was elevated in lung slices exposed to glucoraphanin. GSTα protein levels were increased by glucoraphanin and, to a much lesser extent, glucoerucin. It may be concluded that intact glucosinolates can modulate the activity of pulmonary carcinogen-metabolising enzyme systems, and can thus contribute to the documented chemopreventive activity of cruciferous vegetables in the lung.

Antiinflammatory activity of glucomoringin isothiocyanate in a mouse model of experimental autoimmune encephalomyelitis

Glucomoringin (4(α-L-rhamnosyloxy)-benzyl glucosinolate) (GMG) is an uncommon member of glucosinolate group belonging to the Moringaceae family, of which Moringa oleifera Lam. is the most widely distributed. Bioactivation of GMG with the enzyme myrosinase forms the corresponding isothiocyanate (4(α-L-rhamnosyloxy)-benzyl isothiocyanate) (GMG-ITC), which can play a key role in antitumoral activity and counteract the inflammatory response. The aim of this study was to assess the effect of GMG-ITC treatment in an experimental mouse model of multiple sclerosis (MS), an inflammatory demyelinating disease with neurodegeneration characterized by demyelinating plaques, neuronal, and axonal loss. For this reason, C57Bl/6 male mice were injected with myelin oligodendrocyte glycoprotein35-55 which is able to evoke an autoimmune response against myelin fibers miming human multiple sclerosis physiopatogenesis. Results clearly showed that the treatment was able to counteract the inflammatory cascade that underlies the processes leading to severe MS. In particular, GMG-ITC was effective against proinflammatory cytokine TNF-α. Oxidative species generation including the influence of iNOS, nitrotyrosine tissue expression and cell apoptotic death pathway was also evaluated resulting in a lower Bax/Bcl-2 unbalance. Taken together, this work adds new interesting properties and applicability of GMG-ITC and this compound can be suggested as a useful drug for the treatment or prevention of MS, at least in association with current conventional therapy.

Comparison of bioactive phytochemical content and release of isothiocyanates in selected brassica sprouts

The consumption of brassica sprouts as raw vegetables provides a fair amount of glucosinolates (GLs) and active plant myrosinase, which enables the breakdown of GLs into health-promoting isothiocyanates (ITCs). This study reports the determination of the main constituents related to human health found in edible sprouts of two Brassica oleracea varieties, broccoli and Tuscan black kale, and two Raphanus sativus varieties, Daikon and Sango. Radish sprouts exhibited the highest ability to produce ITCs, with Daikon showing the greatest level of conversion of GLs into bioactive ITCs (96.5%), followed by Sango (90.0%). Tuscan black kale gave a value of 68.5%, whereas broccoli displayed the lowest with 18.7%. ITCs were not the exclusive GL breakdown products in the two B. oleracea varieties, since nitriles were also produced, thus accounting for the lower conversion observed. Measuring the release of plant ITCs is a valuable tool in predicting the potential level of exposure to these bioactive compounds after the consumption of raw brassica sprouts.

Antibacterial Activity of Glucomoringin Bioactivated with Myrosinase against Two Important Pathogens Affecting the Health of Long-Term Patients in Hospitals

Glucosinolates (GLs) are natural compounds present in species of the order Brassicales and precursors of bioactive isothiocyanates (ITCs). In the recent years, they have been studied mainly for their chemopreventive as well as novel chemotherapeutics properties. Among them 4-(α-L-rhamnosyloxy)benzyl glucosinolate (glucomoringin; GMG), purified from seeds of Moringa oleifera Lam., a plant belonging to the Moringaceae family, represents an uncommon member of the GL family with peculiar characteristics. This short communication reports new evidences about the properties of GMG and presents a new innovative utilization of the molecule. The bioactivation of GMG by myrosinase enzyme just before treatment, permits to maximize the power of the final product of the reaction, which is the 4-(α-L-rhamnosyloxy)benzyl isothiocyanate (GMG-ITC). We tested the antibiotic activity of this latter compound on two strains of pathogens affecting the health of patients in hospital, namely Staphylococcus aureus and Enterococcus casseliflavus, and on the yeast Candida albicans. Results show that the sensibility of S. aureus BAA-977 strain and E. casseliflavus to GMG-ITC treatment reveals an important possible application of this molecule in the clinical care of patients, more and more often resistant to traditional therapies.

Vitexin-2-O-xyloside, raphasatin and (-)-epigallocatechin-3-gallate synergistically affect cell growth and apoptosis of colon cancer cells.

Cytotoxic effects of the combination of the food components vitexin-2-O-xyloside (X), raphasatin (4-methylsulphanyl-3-butenyl isothiocyanates; G) and (-)-epigallocatechin-3-gallate (E) were investigated in colon (LoVo and CaCo-2) and breast (MDA-MB-231 and MCF-7) cancer cells. Breast cancer cells were more resistant than colon cells to X, G and E inhibition. On the contrary, marked synergistic effects among X, G and E on cell growth were found in both colon cancer cells. Further analysis revealed a G0/G1 arrest of the phase cell progression and apoptosis, linked to modulation of Bax, Bcl2, caspase-9 and poly(ADP-ribose) polymerase as well as Reactive Oxygen Species (ROS) generation in both colon cancer cells, whereas apoptosis and ROS were not significantly detected in normal human lymphocytes. We conclude that the X, G and E mixture might act by mitochondrial pathway activation of apoptosis, possibly elicited by ROS and the mixture may be effective in the chemoprevention of colon cancer.

Protective role of (RS )-glucoraphanin bioactivated with myrosinase in an experimental model of multiple sclerosis.

The discovery of new natural compounds with pharmacological properties is a field of interest widely growing. Recent literature shows that Brassica vegetables (Cruciferae) possess therapeutic effects particularly ascribed due to their content in glucosinolates, which upon myrosinase hydrolysis release the corresponding isothiocyanates. This study examines the potential neuroprotective and immunomodulatory effects of (RS)‐glucoraphanin from Tuscan black kale (Brassica oleracea L. var. acephala sabellica) bioactivated with myrosinase (bioactive RS‐GRA) (10 mg/kg/day intraperitoneally), in an experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis.

Taste detection of the non-volatile isothiocyanate moringin results in deterrence to glucosinolate-adapted insect larvae

Isothiocyanates (ITCs), released from Brassicales plants after hydrolysis of glucosinolates, are known for their negative effects on herbivores but mechanisms have been elusive. The ITCs are initially present in dissolved form at the site of herbivore feeding, but volatile ITCs may subsequently enter the gas phase and all ITCs may react with matrix components. Deterrence to herbivores resulting from topically applied volatile ITCs in artificial feeding assays may hence lead to ambiguous conclusions. In the present study, the non-volatile ITC moringin (4-(α-L-rhamnopyranosyloxy)benzyl ITC) and its glucosinolate precursor glucomoringin were examined for effects on behaviour and taste physiology of specialist insect herbivores of Brassicales. In feeding bioassays, glucomoringin was not deterrent to larvae of Pieris napi (Lepidoptera: Pieridae) and Athalia rosae (Hymenoptera: Tenthredinidae), which are adapted to glucosinolates. Glucomoringin stimulated feeding of larvae of the related Pieris brassicae (Lepidoptera: Pieridae) and also elicited electrophysiological activity from a glucosinolate-sensitive gustatory neuron in the lateral maxillary taste sensilla. In contrast, the ITC moringin was deterrent to P. napi and P. brassicae at high levels and to A. rosae at both high and low levels when topically applied to cabbage leaf discs (either 12, 120 or 1200 nmol moringin per leaf disc of 1cm diameter). Survival of A. rosae was also significantly reduced when larvae were kept on leaves treated with moringin for several days. Furthermore, moringin elicited electrophysiological activity in a deterrent-sensitive neuron in the medial maxillary taste sensillum of P. brassicae, providing a sensory mechanism for the deterrence and the first known ITC taste response of an insect. In simulated feeding assays, recovery of moringin was high, in accordance with its non-volatile nature. Our results demonstrate taste-mediated deterrence of a non-volatile, natural ITC to glucosinolate-adapted insects.

4(α-l-rhamnosyloxy)-benzyl isothiocyanate, a bioactive phytochemical that attenuates secondary damage in an experimental model of spinal cord injury.

4(α-l-Rhamnosyloxy)-benzyl isothiocyanate (glucomoringin isothiocyanate; GMG-ITC) is released from the precursor 4(α-l-rhamnosyloxy)-benzyl glucosinolate (glucomoringin; GMG) by myrosinase (β-thioglucoside glucohydrolase; E.C. 3.2.1.147) catalyzed hydrolysis. GMG is an uncommon member of the glucosinolate group as it presents a unique characteristic consisting in a second glycosidic residue within the side chain. It is a typical glucosinolate found in large amounts in the seeds of Moringa oleifera Lam., the most widely distributed plant of the Moringaceae family. GMG was purified from seed-cake of M. oleifera and was hydrolyzed by myrosinase at neutral pH in order to form the corresponding GMG-ITC. This bioactive phytochemical can play a key role in counteracting the inflammatory response connected to the oxidative-related mechanisms as well as in the control of the neuronal cell death process, preserving spinal cord tissues after injury in mice. Spinal cord trauma was induced in mice by the application of vascular clips (force of 24g) for 1 min., via four-level T5-T8 after laminectomy. In particular, the purpose of this study was to investigate the dynamic changes occurring in the spinal cord after ip treatment with bioactive GMG-ITC produced 15 min before use from myrosinase-catalyzed hydrolysis of GMG (10mg/kg body weight+5 μl Myr mouse/day). The following parameters, such as histological damage, distribution of reticular fibers in connective tissue, nuclear factor (NF)-κB translocation and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α) degradation, expression of inducible Nitric Oxide Synthases (iNOS), as well as apoptosis, were evaluated. In conclusion, our results show a protective effect of bioactive GMG-ITC on the secondary damage, following spinal cord injury, through an antioxidant mechanism of neuroprotection. Therefore, the bioactive phytochemical GMG-ITC freshly produced before use by myrosinase-catalyzed hydrolysis of pure GMG, could prove to be useful in the treatment of spinal cord trauma.

Anti-inflammatory and antioxidant effects of a combination of cannabidiol and moringin in LPS-stimulated macrophages.

Inflammatory response plays an important role in the activation and progress of many debilitating diseases. Natural products, like cannabidiol, a constituent of Cannabis sativa, and moringin, an isothiocyanate obtained from myrosinase-mediated hydrolysis of the glucosinolate precursor glucomoringin present in Moringa oleifera seeds, are well known antioxidants also endowed with anti-inflammatory activity. This is due to a covalent-based mechanism for ITC, while non-covalent interactions underlie the activity of CBD. Since these two mechanisms are distinct, and the molecular endpoints are potentially complementary, we investigated in a comparative way the protective effect of these compounds alone or in combination on lipopolysaccharide-stimulated murine macrophages. Our results show that the cannabidiol (5μM) and moringin (5μM) combination outperformed the single constituents that, at this dosage had only a moderate efficacy on inflammatory (Tumor necrosis factor-α, Interleukin-10) and oxidative markers (inducible nitric oxide synthase, nuclear factor erythroid 2-related factor 2, nitrotyrosine). Significant upregulation of Bcl-2 and downregulation of Bax and cleaved caspase-3 was observed in cells treated with cannabidiol-moringin combination. Treatment with the transient receptor potential vanilloid receptor 1 antagonist was detrimental for the efficacy of cannabidiol, while no effect was elicited by cannabinoid receptor 1 and cannabinoid receptor 2 antagonists. None of these receptors was involved in the activity of moringin. Taken together, our in vitro results testify the anti-inflammatory, antioxidative, and anti-apoptotic effects of the combination of cannabidiol and moringin.