Angiogenic and cell proliferating action of the natural diarylnonanoids, malabaricone B and malabaricone C during healing of indomethacin-induced gastric ulceration

Malabaricone C derived from nutmeg inhibits arachidonate 5-lipoxygenase activity and ameliorates psoriasis-like skin inflammation in mice

As pro-inflammatory lipid mediators, leukotrienes have pathophysiological activities in several inflammatory diseases, including psoriasis. In the biosynthesis of leukotrienes from arachidonic acid, 5-lipoxygenase catalyzes the first two steps. In the present study, we showed that nutmeg (Myristica fragrans) strongly inhibited the catalytic activity of 5-lipoxygenase. To characterize the bioactive component(s) of nutmeg, we performed 5-lipoxygenase inhibitory activity-guided fractionation of aqueous ethanol extract of nutmeg, resulting in the isolation of malabaricone C having antioxidant activity. Malabaricone C exhibited potent competitive inhibition of 5-lipoxygenase with an IC₅₀ value of 0.2 μM. In mice with imiquimod-induced psoriasis-like skin lesions, topical application of 2 mM malabaricone C significantly ameliorated hyperplasia and inflammatory cell infiltration, and suppressed the expression of the psoriasis-associated genes S100a9, Krt1, Il17a, and Il22. Lipid metabolome analysis of these psoriasis-like skin lesions showed that malabaricone C markedly decreased the level of leukotriene B₄ but did not significantly increase the other pro-inflammatory lipid mediators. These findings suggest that malabaricone C decreases LTB₄ by the 5-lipoxygenase inhibition and ameliorates the symptoms of psoriasis-like skin inflammation.

Improved Image Analysis for Measuring Gastric Ulcer Index in Animal Models and Clinical Diagnostic Data

Gastric ulcers are one of the most common gastrointestinal diseases. In this study, as an attempt to reduce the minimal error in clinical observations during the diagnosis of gastric ulcers, the applicability of improved ImageJ analysis (IA) was investigated by comparing the results of animal experiments and clinical data. As a result, IA exhibited a significantly improved potential for determining the ulcer index (UI) of clinical data sheets compared to those rated directly by conventional clinical observation (CCO). This indicated that IA enhanced the reproducibility of the measurement of gastric UI using a Bland-Altman plot, resulting in a reduced deviation of each UI value. In addition, it was confirmed that errors in gastric UI decisions can be reduced by adjusting RGB values in diagnostic clinical data (i.e., adjusting to 100 is relatively better than adjusting to 50 or 200). Together, these results suggest that the new enhanced IA could be compatible with novel applications for measuring and evaluating gastric ulcers in clinical settings, meaning that the developed method could be used not only as an auxiliary tool for CCO, but also as a pipeline for ulcer diagnosis.

Malabaricone C Attenuates Nonsteroidal Anti-Inflammatory Drug-Induced Gastric Ulceration by Decreasing Oxidative/Nitrative Stress and Inflammation and Promoting Angiogenic Autohealing

Aims: Nonsteroidal anti-inflammatory drugs (NSAIDs), among the most commonly used drugs worldwide, are associated with gastrointestinal (GI) complications that severely limit the clinical utility of this essential class of pain medications. Here, we mechanistically dissect the protective impact of a natural product, malabaricone C (Mal C), on NSAID-induced gastropathy. Results: Mal C dose dependently diminished erosion of the stomach lining and inflammation in mice treated with NSAIDs with the protective impact translating to improvement in survival. By decreasing oxidative and nitrative stress, Mal C treatment prevented NSAID-induced mitochondrial dysfunction and cell death; nuclear factor κ-light-chain enhancer of activated B cell induction, release of proinflammatory cytokines and neutrophil infiltration; and disruptions in the vascular endothelial growth factor/endostatin balance that contributes to mucosal autohealing. Importantly, Mal C failed to impact the therapeutic anti-inflammatory properties of multiple NSAIDs in a model of acute inflammation. In all assays tested, Mal C proved as or more efficacious than the current first-line therapy for NSAID-dependent GI complications, the proton pump inhibitor omeprazole. Innovation: Given that omeprazole-mediated prophylaxis is, itself, associated with a shift in NSAID-driven GI complications from the upper GI to the lower GI system, there is a clear and present need for novel therapeutics aimed at ameliorating NSAID-induced gastropathy. Mal C provided significant protection against NSAID-induced gastric ulcerations impacting multiple critical signaling cascades contributing to inflammation, cell loss, extracellular matrix degradation, and angiogenic autohealing. Conclusion: Thus, Mal C represents a viable lead compound for the development of novel gastroprotective agents.

Thiol antioxidants sensitize malabaricone C induced cancer cell death via reprogramming redox sensitive p53 and NF-κB proteins in vitro and in vivo

Specific focus on "redox cancer therapy" by targeting drugs to redox homeostasis of the cancer cells is growing rapidly. Recent clinical studies showed that N-acetyl cysteine (NAC) treatment significantly decreased the metabolic heterogeneity and reduced Ki67 (a proliferation marker) with simultaneous enhancement in apoptosis of tumor cells in patients. However, it is not yet precisely known how thiol antioxidants enhance killing of cancer cells in a context dependent manner. To this end, we showed that a dietary compound, malabaricone C (mal C) generated copious amounts of reactive oxygen species (ROS) and also reduced GSH level in lung cancer cells. Paradoxically, although antioxidants supplementation reduced mal C-induced ROS, thiol-antioxidants (NAC/GSH) restored intracellular GSH level but enhanced DNA DSBs and apoptotic cell death induced by mal C. Our results unraveled two tightly coupled biochemical mechanisms attributing this sensitization process by thiol antioxidants. Firstly, thiol antioxidants enable the "catechol-quinone redox cycle" of mal C and ameliorate ROS generation and bio-molecular damage (DNA and protein). Secondly, thiol antioxidants cause rapid glutathionylation of transcription factors [p53, p65 (NF-κB) etc.], oxidized by mal C, and abrogates their nuclear sequestration and transcription of the anti-apoptotic genes. Furthermore, analyses of the mitochondrial fractions of p53 expressing and silenced cells revealed that cytoplasmic accumulation of glutathionylated p53 (p53-SSG) triggers a robust mitochondrial death process. Interestingly, mutation of redox sensitive cysteine residues at 124, 141 and 182 position in p53 significantly reduces mal C plus NAC mediated sensitization of cancer cells. The preclinical results, in two different tumor models in mice, provides further support our conclusion that NAC is able to sensitize mal C induced suppression of tumor growth in vivo.

Phenolic compounds from nutmeg (Myristica fragrans Houtt.) inhibit the endocannabinoid-modulating enzyme fatty acid amide hydrolase

OBJECTIVES

The study aimed to identify nutmeg compounds that indirectly interact with the endocannabinoid system through inhibition of the fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) enzymes.

METHODS

Thirteen compounds were screened for FAAH and MAGL inhibition. Compounds demonstrating significant FAAH inhibition were evaluated to determine the halfmaximal inhibitory concentration (IC₅₀ ). The most potent compound was investigated in the elevated plus maze (EPM) rodent anxiety model.

KEY FINDINGS

Three compounds, licarin A (9), 5'-methoxylicarin A (8) and malabaricone C (6) were most active in inhibiting FAAH with IC₅₀ of 7.02 μm ± 2.02, 4.57 μm ± 0.66 and 38.29 μm ± 6.18, respectively. None of the purified compounds showed significant MAGL inhibition. Because of its relative high potency and selectivity, compound 8 was further evaluated in the EPM animal model of anxiety. The compound showed significant increase in number of open arm entries (P < 0.05) when administered at 120 mg/kg dose. No effect was observed on the locomotor activity.

CONCLUSIONS

Results collected introduce active nutmeg compounds as potential leads for further development. Of the three compounds, 8 possesses highest potency and FAAH selectivity as well as anxiolytic activity. Furthermore, in vivo testing in appropriate behavioural animal paradigms is warranted.

Potential Antiulcer Agents From Plants: A Comprehensive Review

Background:

Peptic ulcer is a deep gastrointestinal erosion disorder that involves the entire mucosal thickness and can even penetrate the muscular mucosa. Nowadays, several plants and compounds derived from it have been screened for their antiulcer activity. In the last few years, there has been an exponential growth in the field of herbal medicine. This field has gained popularity in both developing and developed countries because of their natural origin and less side effects.

Objective:

This review aims to provide a comprehensive summary of currently available knowledge of medicinal plants and phytoconstituents reported for their anti-ulcer properties.

Methods:

The worldwide accepted database like SCOPUS, PUBMED, SCIELO, NISCAIR, ScienceDirect, Springerlink, Web of Science, Wiley, SciFinder and Google Scholar were used to retrieve available published literature.

Results:

A comprehensive review of the present paper is an attempt to list the plants with antiulcer activity. The review narrates the dire need to explore potential chemical moieties that exert an antiulcer effect, from unexploited traditional plants. Furthermore, the present study reveals the intense requirement to exploit the exact mechanism through which either the plant extracts or their active constituents exhibit their antiulcer properties.

Conclusion:

This article is the compilation of the plants and its constituents reported for the treatment of peptic ulcers. The Comprehensive data will surely attract the number of investigators to initiate further research that might lead to the drugs for the treatment of ulcers. As sufficient scientific data is not available on plants, most of the herbals cannot be recommended for the treatment of diseases. This can be achieved by research on pure chemical structures derived from plants or to prepare new lead compounds with proven beneficial preclinical in vitro and in vivo effects. However, a lot remains to be done in further investigations for the better status of medicinal plants.

Malabaricone C as Natural Sphingomyelin Synthase Inhibitor against Diet-Induced Obesity and Its Lipid Metabolism in Mice

The interaction between natural occurring inhibitors and targeted membrane proteins could be an alternative medicinal strategy for the treatment of metabolic syndrome, notably, obesity. In this study, we identified malabaricones A-C and E (1-4) isolated from the fruits of Myristica cinnamomea King as natural inhibitors for sphingomyelin synthase (SMS), a membrane protein responsible for sphingolipid biosynthesis. Having the most promising inhibition, oral administration of compound 3 exhibited multiple efficacies in reducing weight gain, improving glucose tolerance, and reducing hepatic steatosis in high fat diet-induced obesity mice models. Liver lipid analysis revealed a crucial link between the SMS activities of compound 3 and its lipid metabolism in vitro and in vivo. The nontoxic nature of compound 3 makes it a suitable candidate in search of drugs which can be employed in the treatment and prevention of obesity.

Spice-derived phenolic, malabaricone B induces mitochondrial damage in lung cancer cellsviaa p53-independent pathway

The spice-derived phenolic, malabaricone B induces mitochondrial cell death and reduces lung tumor growthin vivo.

Healing and Antisecretory Effects of Aqueous Extract of Eremomastax speciosa (Acanthaceae) on Unhealed Gastric Ulcers

OBJECTIVE

This work investigated the healing and antisecretory effects of the aqueous extract of Eremomastax speciosa on "unhealed gastric ulcers" associated with gastric acid hypersecretion.

MATERIALS AND METHODS

"Unhealed gastric ulcers" were induced using indomethacin following the establishment of acetic-acid-induced chronic gastric ulcers. The extract (200 and 400 mg/kg, per os) was administered concomitantly with indomethacin (1 mg/kg, subcutaneously). The effects of the extract on both basal and histamine-stimulated gastric acid secretion were determined. Mucus secretion and oxidative stress parameters were measured, and histological assessment of ulcer healing was carried out.

RESULTS

The extract significantly promoted the healing process in rats subjected to "unhealed gastric ulcers" (82.4-88.5% healing rates). Treatment with the extract significantly reduced the basal (25.95-49.51% reduction rates) and histamine-stimulated (24.25-47.41%) acid secretions. The healing effect of the extract was associated with a significant (p < 0.05) increase of mucus secretion and concentrations of antioxidant enzymes compared with the controls. The extract at the highest dose showed normalization of the mucosa, without glandular destruction and with the disappearance of fibrosis and lymphocyte infiltration.

CONCLUSION

The abilities of the extract to increase mucus secretion, to reinforce antioxidant status, and to inhibit acid secretion would be some of the mechanisms by which this extract would accelerate the healing process in "unhealed gastric ulcers."

Total Syntheses of Malabaricones B and C via a Cross-Metathesis Strategy

The malabaricones A-D belong to the class of diarylnonanoids isolated from the Myristicaceae family of plants. Although malabaricone C displayed various interesting biological activities, its isolation remains tedious due to its close chemical similarity to malabaricones A, B, and D. Therefore, development of an efficient synthesis route has become essential to cater to the need of large amounts of malabaricone C for its pharmacological profiling. So far there is only one report of the synthesis of malabaricone C through a lengthy sequence of reactions. We have developed an efficient and short route for the syntheses of malabaricones B and C, which will also provide a convenient access to all other members of the malabaricone family. Synthesis of an important building block, ω-aryl heptyl bromide, employed in the synthesis was realized by adopting a cross-metathesis reaction as the key step.

Chemical diversity and pharmacological significance of the secondary metabolites of nutmeg (Myristica fragrans Houtt.)

Nutmeg is a valued kitchen spice that has been used for centuries all over the world. In addition to its use in flavoring foods and beverages, nutmeg has been used in traditional remedies for stomach and kidney disorders. The antioxidant, antimicrobial and central nervous system effects of nutmeg have also been reported in literature. Nutmeg is a rich source of fixed and essential oil, triterpenes, and various types of phenolic compounds. Many of the secondary metabolites of nutmeg exhibit biological activities that may support its use in traditional medicine. This article provides an overview of the chemistry of secondary metabolites isolated from nutmeg kernel and mace including common methods for analysis of extracts and pure compounds as well as recent approaches towards total synthesis of some of the major constituents. A summary of the most significant pharmacological investigations of potential drug leads isolated from nutmeg and reported in the last decade is also included.

Epithelial MUC1 promotes cell migration, reduces apoptosis and affects levels of mucosal modulators during acetylsalicylic acid (aspirin)-induced gastropathy

MUC1, a transmembrane mucin highly expressed in the stomach, is up-regulated after acetylsalicylic acid (ASA) intake in humans and mice. Epithelial Muc1/MUC1 facilitates mucosal wound healing by enhancing cell migration and proliferation, protecting against apoptosis and mediating expression of mucosal modulators.

Efficacy and safety of herbal medicines in treating gastric ulcer: A review

Gastric ulcer is a common disorder of the digestive system. Current therapeutic regimens largely rely on Western medicine. However, numerous studies have demonstrated that herbal medicines can effectively treat gastric ulcer in humans and various animal models via divergent mechanisms. This review updates the efficacy and safety of herbal medicines in treating gastric ulcer, and the mechanisms of their action in humans and animal models. Studies have demonstrated that the efficacy of herbal medicines is comparable or superior to that of drugs such as omeprazole or cimetidine in humans and animal models, and herbal medicines display fewer adverse effects. The mechanisms by which herbal medicines benefit gastric ulcer include stimulation of mucous cell proliferation, anti-oxidation, and inhibition of gastric acid secretion and H(+)/K(+)-ATPase activity. Some herbal medicines also exhibit antimicrobial properties. Utilization of herbal medicines could be a valuable alternative to treat gastric ulcer in humans effectively, with few adverse effects.

Roles of pro-angiogenic and anti-angiogenic factors as well as matrix metalloproteinases in healing of NSAID-induced small intestinal ulcers in rats

AIMS

We examined changes in the expression of a pro-angiogenic factor, vascular endothelial growth factor (VEGF), and an anti-angiogenic factor, endostatin, as well as matrix metalloproteinase (MMP)-2 and MMP-9 in the rat small intestine after administration of indomethacin and investigated the roles of these factors in the healing of indomethacin-induced small intestinal ulcers.

MAIN METHODS

Male SD rats were given indomethacin (10mg/kg) p.o. and euthanized at various time points (3-24h and 2-7days) after the administration. To impair the healing of these lesions, low-dose of indomethacin (2mg/kg) was given p.o. once daily for 6days starting 1day after ulceration. Levels of VEGF, endostatin, MMP-2 and MMP-9 were determined by Western blotting.

KEY FINDINGS

The expression of both VEGF and endostatin was upregulated after the ulceration. Repeated administration of low-dose indomethacin impaired the ulcer healing with a decrease of VEGF expression and a further increase of endostatin expression, resulting in a marked decrease in the ratio of VEGF/endostatin expression. The levels of MMP-2 and MMP-9 were both significantly increased after the ulceration, but these responses were suppressed by the repeated indomethacin treatment. The healing of these ulcers was significantly delayed by the repeated administration of MMP inhibitors such as ARP-101 and SB-3CT.

SIGNIFICANCE

The results confirm the importance of the balance between pro-angiogenic and anti-angiogenic activities in the healing of indomethacin-induced small intestinal damage and further suggest that the increased expression of MMP-2 and MMP-9 is another important factor for ulcer healing in the small intestine.

Molecular mechanism of the anti-inflammatory activity of a natural diarylnonanoid, malabaricone C

The spice-derived phenolic, malabaricone C (mal C), has recently been shown to accelerate healing of the indomethacin-induced gastric ulceration in mice. In this study, we explored its anti-inflammatory activity and investigated the underlying mechanism of the action. Mal C suppressed the microvascular permeability and the levels of tumor necrosis factor-α, interleukin-1β, and nitric oxide in the lipopolysaccharide (LPS)-administered mice. At a dose of 10 mg/kg, it showed anti-inflammatory activity comparable to that of omeprazole (5 mg/kg) and dexamethasone (50 mg/kg). It also reduced the expression and activities of inducible nitric oxide synthase, cyclooxygenase-2, as well as the pro- vs anti-inflammatory cytokine ratio in the LPS-treated RAW macrophages. Mal C was found to inhibit LPS-induced NF-kB activation in RAW 264.7 cells by blocking the MyD88-dependent pathway. Mal C suppressed NF-κB activation and iNOS promoter activity, which correlated with its inhibitory effect on IκB phosphorylation and degradation, and NF-κB nuclear translocation, in the LPS-stimulated macrophages. It also inhibited LPS-induced phosphorylation of p38 and JNK, which are also upstream activators of NF-κB, without affecting Akt phosphorylation. Mal C also effectively blocked the PKR-mediated activation of NF-κB. These findings indicate that mal C exerts an anti-inflammatory effect through NF-κB-responsive inflammatory gene expressions by inhibiting the p38 and JNK-dependent canonical NF-κB pathway as well as the PKR pathway, and is a potential therapeutic agent against acute inflammation.

Pharmacologic attenuation of pelvic pain in a murine model of interstitial cystitis

BACKGROUND

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a bladder disease that causes debilitating pelvic pain of unknown origin, and IC/PBS symptoms correlate with elevated bladder lamina propria mast cell counts. Similar to IC/PBS patients, pseudorabies virus (PRV) infection in mice induces a neurogenic cystitis associated with bladder lamina propria mast cell accumulation and pelvic pain. We evaluated several drugs to determine the effectiveness of reducing PRV-induced pelvic pain.

METHODS

Neurogenic cystitis was induced by the injection of Bartha's strain of PRV into the abductor caudalis dorsalis tail base muscle of female C57BL/6 mice. Therapeutic modulation of pelvic pain was assessed daily for five days using von Frey filament stimulation to the pelvic region to quantify tactile allodynia.

RESULTS

Significant reduction of PRV-induced pelvic pain was observed for animals treated with antagonists of neurokinin receptor 1 (NK1R) and histamine receptors. In contrast, the H1R antagonist hydroxyzine, proton pump inhibitors, a histamine receptor 3 agonist, and gabapentin had little or no effect on PRV-induced pelvic pain.

CONCLUSION

These data demonstrate that bladder-associated pelvic pain is attenuated by antagonists of NK1R and H2R. Therefore, NK1R and H2R represent direct therapeutic targets for pain in IC/PBS and potentially other chronic pain conditions.

Regulation of arginase/nitric oxide synthesis axis via cytokine balance contributes to the healing action of malabaricone B against indomethacin-induced gastric ulceration in mice

The role of the arginine-metabolism in the healing action of the Myristica malabarica phenol malabaricone B (mal B) and omeprazole against indomethacin-induced stomach ulceration in mouse was investigated. Indomethacin (18 mg kg- 1) was found to induce maximum stomach ulceration in Swiss albino mice on the 3rd day of its administration, which was associated with reduced arginase activity (30.8%, P < 0.01), eNOS expression, along with increased iNOS expression, total NOS activity (5.55 folds, P < 0.001), NO generation (2.19 folds, P < 0.001), and ratio of pro-/anti-inflammatory cytokines. Besides providing comparable healing as omeprazole (3 mg kg- 1 x 3 days), mal B (10 mg kg- 1 x 3 days, p. o.) shifted the iNOS/NO axis to the arginase/polyamine axis as revealed from the increased arginase activity (51.6%, P < 0.001), eNOS expression, and reduced iNOS expression, total NOS activity (approximately 75%, P < 0.001), and NO level (50.6%, P < 0.01). These could be attributed to a favourable anti/pro inflammatory cytokines ratio, generated by mal B. The healing by omeprazole was however, not significantly associated with those parameters.