Inhibitory effect of citral on NO production by suppression of iNOS expression and NF-κB activation in RAW264.7 cells

Citral in lemon myrtle, lemongrass, litsea, and melissa essential oils suppress the growth and invasion of breast cancer cells

OBJECTIVE

Although cancer therapy suppresses recurrence and prolongs life, it may be accompanied by strong side effects; thus, there is a strong demand for the development effective treatments with fewer side effects. Cancer therapy using plant-derived essential oils is attracting attention as one promising method. This study investigated the antitumor effects of essential oil volatiles on breast cancer cells and identifies four essential oils that display antitumor activity.

METHODS

Breast cancer cells were cultured in a 96-well plate, then one of twenty essential oils was added dropwise to the central well. The plate was incubated at 37 °C for 48 h and the effect of the volatile components of each essential oil on the surrounding breast cancer cell growth ability was examined using an MTT assay. Gas chromatography was used to investigate the concentration of the transpiration components that may affect cancer cells.

RESULTS

Of the 20 essential oils, Lemongrass, Lemon myrtle, Litsea, and Melissa displayed strong anti-tumor effects. These essential oils inhibited the growth of nearby breast cancer cells, even when diluted more than 500-fold. The transpiration component of lemon Myrtle showed the strongest antitumor effect, but was the least cytotoxic to mononuclear cells in normal peripheral blood (PBMC). Each of these essential oils contained a very large amount of citral. The IC50 against breast cancer cells when citral was volatilized from each essential oil was 1.67 µL/mL for geranial and 1.31 µL/mL for neral. Volatilized citral alone showed strong anti-proliferation and infiltration-inhibiting effects.

CONCLUSION

The transpiration components of Lemongrass, Lemon myrtle, Litsea, and Melissa are thought to inhibit breast cancer cell proliferation due to their high levels of citral.

The Analgesic Potential of Litsea Species: A Systematic Review

Various plant species from the Litsea genus have been claimed to be beneficial for pain relief. The PRISMA approach was adopted to identify studies that reported analgesic properties of plants from the Litsea genus. Out of 450 records returned, 19 primary studies revealed the analgesic potential of nine Litsea species including (1) Litsea cubeba, (2) Litsea elliptibacea, (3) Litsea japonica, (4) Litsea glutinosa, (5) Litsea glaucescens, (6) Litsea guatemalensis, (7) Litsea lancifolia, (8) Litsea liyuyingi and (9) Litsea monopetala. Six of the species, 1, 3, 4, 7, 8 and 9, demonstrated peripheral antinociceptive properties as they inhibited acetic-acid-induced writhing in animal models. Species 1, 3, 4, 8 and 9 further showed effects via the central analgesic route at the spinal level by increasing the latencies of heat stimulated-nocifensive responses in the tail flick assay. The hot plate assay also revealed the efficacies of 4 and 9 at the supraspinal level. Species 6 was reported to ameliorate hyperalgesia induced via partial sciatic nerve ligation (PSNL). The antinociceptive effects of 1 and 3 were attributed to the regulatory effects of their bioactive compounds on inflammatory mediators. As for 2 and 5, their analgesic effect may be a result of their activity with the 5-hydroxytryptamine 1A receptor (5-HT1AR) which disrupted the pain-stimulating actions of 5-HT. Antinociceptive activities were documented for various major compounds of the Litsea plants. Overall, the findings suggested Litsea species as good sources of antinociceptive compounds that can be further developed to complement or substitute prescription drugs for pain management.

To Explore the Putative Molecular Targets of Diabetic Nephropathy and their Inhibition Utilizing Potential Phytocompounds

BACKGROUND

This review critically addresses the putative molecular targets of Diabetic Nephropathy (DN) and screens effective phytocompounds that can be therapeutically beneficial, and highlights their mechanistic modalities of action.

INTRODUCTION

DN has become one of the most prevalent complications of clinical hyperglycemia, with individual-specific variations in the disease spectrum that leads to fatal consequences. Diverse etiologies involving oxidative and nitrosative stress, activation of polyol pathway, inflammasome formation, Extracellular Matrix (ECM) modifications, fibrosis, and change in dynamics of podocyte functional and mesangial cell proliferation adds up to the clinical complexity of DN. Current synthetic therapeutics lacks target-specific approach, and is associated with the development of inevitable residual toxicity and drug resistance. Phytocompounds provides a vast diversity of novel compounds that can become an alternative therapeutic approach to combat the DN.

METHODS

Relevant publications were searched and screened from research databases like GOOGLE SCHOLAR, PUBMED and SCISEARCH. Out of 4895 publications, the most relevant publications were selected and included in this article.

RESULT

This study critically reviews over 60 most promising phytochemical and provides with their molecular targets, that can be of pharmacological significance in context to current treatment and concomitant research in DN.

CONCLUSION

This review highlights those most promising phytocompounds that have the potential of becoming new safer naturally-sourced therapeutic candidates and demands further attention at clinical level.

Mechanisms and Applications of Citral's Antimicrobial Properties in Food Preservation and Pharmaceuticals Formulations

Citral is a monoterpene constituted by two isomers known as neral and geranial. It is present in different plant sources and recognized as safe (GRAS) by the Food and Drug Administration (FDA). In recent years, investigations have demonstrated that this compound exhibited several biological activities, such as antibacterial, antifungal, antibiofilm, antiparasitic, antiproliferative, anti-inflammatory, and antioxidant properties, by in vitro and in vivo assays. Additionally, when incorporated into different food matrices, citral can reduce the microbial load of pathogenic microorganisms and extend the shelf life. This compound has acceptable drug-likeness properties and does not present any violations of Lipinski's rules, which could be used for drug development. The above shows that citral could be a compound of interest for developing food additives to extend the shelf life of animal and vegetable origin foods and develop pharmaceutical products.

Citral protects against LPS-induced endometritis by inhibiting ferroptosis through activating Nrf2 signaling pathway

INTRODUCTION

Endometritis is the inflammatory condition of the uterus. Citral, a component of lemongrass oil, is known to exhibit anti-inflammatory activity.

AIM

The effects of citral on LPS-induced endometritis were tested and the mechanisms were investigated.

METHODS

LPS-induced endometritis mice model was established and the effects of citral were detected using this model. Inflammatory cytokines were tested by ELISA. Ferroptosis was assessed by detecting GSH, ATP, MDA, and Fe2+ levels. Signaling pathway was tested by western blot analysis.

RESULTS

Citral prevented LPS-induced endometritis through attenuating uterine pathological changes and inflammatory cytokine release. Meanwhile, citral prevents LPS-induced ferroptosis through attenuating MDA and Fe2+ levels, as well as increasing ATP and GSH levels. Furthermore, citral up-regulated Nrf2 and HO-1 expression and attenuated NF-κB activation. In addition, in Nrf2 knockdown mice, the inhibitory roles of citral on ferroptosis and endometritis were largely reversed.

CONCLUSION

Taken together, citral inhibited LPS-induced endometritis through preventing ferroptosis, which were regulated by Nrf2 signaling pathway.

Orofacial anti-hypernociceptive effect of citral in acute and persistent inflammatory models in rats

Orofacial pain has significant psychological and physiological effects. Citral (3,7-dimethyl-2,6-octadienal) is the main component of Cymbopogon citratus (DC) Stapf, an herb with analgesic properties. Although citral has been considered a potent analgesic, its putative effects on orofacial pain are still unknown.

OBJECTIVE

The objective of this study is to test the hypothesis that citral modulates orofacial pain using two experimental models: formalin-induced hyperalgesia in the vibrissae area and during persistent temporomandibular hypernociception using Complete Freund's Adjuvant - CFA test.

METHODS

For the formalin test, citral (100 and 300 mg/kg, oral gavage) or its vehicle (Tween 80, 1 %) were given 1 h before the formalin injection subcutaneously (sc) into the vibrissae area. For the CFA model, we analyzed the prophylactic (100 mg/kg of citral by oral gavage, 1 h before CFA injection) and the chronic therapeutic (citral treatment 1-hour post-CFA injection and daily post-CFA injection) effect of citral or its vehicle in animals treated with CFA for 8 days.

RESULTS

Citral caused a decrease in formalin-induced local inflammation and the time spent performing nociceptive behavior in a dose-dependent fashion. Similarly, prophylactic and therapeutic citral treatment decreased the CFA-induced persistent mechanical hypernociception in the temporomandibular area.

CONCLUSION

Our data strengthen the notion that citral plays a powerful antinociceptive role by decreasing orofacial hypernociception in formalin and CFA models.

Potential Effects of Geraniol on Cancer and Inflammation-Related Diseases: A Review of the Recent Research Findings

Geraniol (GNL), a natural monoterpene, is found in many essential oils of fruits, vegetables, and herbs, including lavender, citronella, lemongrass, and other medicinal and aromatic plants. GNL is commonly used by the cosmetic and food industries and has shown a wide spectrum of pharmacological activities including anti-inflammatory, anticancer, antimicrobial, antioxidant, and neuroprotective activities. It represents a potential anti-inflammatory agent and a promising cancer chemopreventive agent, as it has been found to be effective against a broad range of cancers, including colon, prostate, breast, lung, skin, kidney, liver, and pancreatic cancer. Moreover, GNL scavenges free radicals and preserves the activity of antioxidant enzymes. In addition, GNL induces apoptosis and cell cycle arrest, modulates multiple molecular targets, including p53 and STAT3, activates caspases, and modulates inflammation via transcriptional regulation. In the present study, different modes of action are described for GNL's activity against cancer and inflammatory diseases. This compound protects various antioxidant enzymes, such as catalase, glutathione-S-transferase, and glutathione peroxidase. Experiments using allergic encephalomyelitis, diabetes, asthma, and carcinogenesis models showed that GNL treatment had beneficial effects with low toxicity. GNL has been shown to be effective in animal models and tumor cell lines, but there have not been any clinical studies carried out for it. The aim of the present review is to provide updated data on the potential effects of GNL on cancer and inflammation, and to enhance our understanding of molecular targets, involved pathways, and the possible use of GNL for clinical studies and therapeutic purposes in the treatment of cancer and inflammation-related diseases.

Host A-to-I RNA editing signatures in intracellular bacterial and single-strand RNA viral infections

Background

Microbial infection is accompanied by remodeling of the host transcriptome. Involvement of A-to-I RNA editing has been reported during viral infection but remains to be elucidated during intracellular bacterial infections.

Results

Herein we analyzed A-to-I RNA editing during intracellular bacterial infections based on 18 RNA-Seq datasets of 210 mouse samples involving 7 tissue types and 8 intracellular bacterial pathogens (IBPs), and identified a consensus signature of RNA editing for IBP infections, mainly involving neutrophil-mediated innate immunity and lipid metabolism. Further comparison of host RNA editing patterns revealed remarkable similarities between pneumonia caused by IBPs and single-strand RNA (ssRNA) viruses, such as altered editing enzyme expression, editing site numbers, and levels. In addition, functional enrichment analysis of genes with RNA editing highlighted that the Rab GTPase family played a common and vital role in the host immune response to IBP and ssRNA viral infections, which was indicated by the consistent up-regulated RNA editing of Ras-related protein Rab27a. Nevertheless, dramatic differences between IBP and viral infections were also observed, and clearly distinguished the two types of intracellular infections.

Conclusion

Our study showed transcriptome-wide host A-to-I RNA editing alteration during IBP and ssRNA viral infections. By identifying and comparing consensus signatures of host A-to-I RNA editing, our analysis implicates the importance of host A-to-I RNA editing during these infections and provides new insights into the diagnosis and treatment of infectious diseases.

Therapeutic Potential of Clove Essential Oil in Diabetes: Modulation of Pro-Inflammatory Mediators, Oxidative Stress and Metabolic Enzyme Activities

Type 1 diabetes is characterized by insulin deficiency due to the destruction of pancreatic β cells, leading to hyperglycemia, which in turn induces vascular complications. In the current study, we investigated the effect of intraperitoneal administration of clove essential oil (CEO: 20 mg/kg body weight) on certain oxidative stress and glucose metabolism enzymes, as well as the expression of proinflammatory mediators. Administration of CEO to diabetic rats showed a significant decline in blood glucose levels, total cholesterol, and xanthine oxidase, compared to the streptozotocin group. Furthermore, these treated rats elicited a notable attenuation in the levels of lipid peroxides, and thiols groups in both liver and brain tissues. The activities of antioxidant and metabolic enzymes were reverted to normality in diabetic upon CEO administration. In addition to its protective effects on red blood cell hemolysis, CEO is a potent α-amylase inhibitor with an IC₅₀ =298.0±2.75 μg/mL. Also, treatment of diabetic rats with CEO significantly reduced the iNOS expression in the spleen. Our data showed that CEO has potential beneficial effects on diabetes, which can possibly prevent the pathogenesis of diabetic micro- and macrovascular complications.

Nephroprotective Activity of Papaloquelite (Porophyllum ruderale) in Thioacetamide-Induced Injury Model

Acute kidney injury and impaired kidney function is associated with reduced survival and increased morbidity. Porophyllum ruderale is an edible plant endemic to Mexico used in Mexican traditional medicine. The aim of this study was to evaluate the nephroprotective effect of a hydroalcoholic extract (MeOH:water 70:30, v/v) from the aerial parts of P. ruderale (HEPr). Firstly, in vitro the antioxidant and anti-inflammatory activity of HEPr was determined; after the in vivo nephroprotective activity of HEPr was evaluated using a thioacetamide-induced injury model in rats. HEPr showed a slight effect on LPS-NO production in macrophages (15% INO at 40 µg/mL) and high antioxidant activity in the ferric reducing antioxidant power (FRAP) test, followed by the activity on DPPH and ABTS radicals test (69.04, 63.06 and 32.96% of inhibition, respectively). In addition, values of kidney injury biomarkers in urine (urobilinogen, hemoglobin, bilirubin, ketones, glucose, protein, pH, nitrites, leukocytes, specific gravity, and the microalbumin/creatinine) and serum (creatinine, urea, and urea nitrogen) of rats treated with HEPr were maintained in normal ranges. Finally, 5-O-caffeoylquinic, 4-O-caffeoylquinic and ferulic acids; as well as 3-O-quercetin glucoside and 3-O-kaempferol glucoside were identified by HPLC as major components of HEPr. In conclusion, Porophyllum ruderale constitutes a source of compounds for the treatment of acute kidney injury.

Newly Designed Quinazolinone Derivatives as Novel Tyrosinase Inhibitor: Synthesis, Inhibitory Activity, and Mechanism

We synthesized a series of quinazolinone derivates as tyrosinase inhibitors and evaluated their inhibition constants. We synthesized 2-(2,6-dimethylhepta-1,5-dien-1-yl)quinazolin-4(3H)-one (Q1) from the natural citral. The concentration, which led to 50% activity loss of Q1, was 103 ± 2 μM (IC₅₀ = 103 ± 2 μM). Furthermore, we considered Q1 to be a mixed-type and reversible tyrosinase inhibitor, and determined the K_I and K_IS inhibition constants to be 117.07 μM and 423.63 μM, respectively. Our fluorescence experiment revealed that Q1 could interact with the substrates of tyrosine and L-DOPA in addition to tyrosinase. Molecular docking studies showed that the binding of Q1 to tyrosinase was driven by hydrogen bonding and hydrophobicity. Briefly, the current study confirmed a new tyrosinase inhibitor, which is expected to be developed into a novel pigmentation drug.

Comparative Evaluation of Locally Administered 2% Gel Fabricated from Lemongrass Polymer and 10% Doxycycline Hyclate Gel as an Adjunct to Scaling and Root Planing in the Treatment of Chronic Periodontitis-A Randomized Controlled Trial

Background: Extracts of medicinal plant like lemongrass offer a new choice for optional antimicrobial therapy against various oral microorganisms. The objective of this study was to assess, verify, and compare the antimicrobial effectiveness of locally administered 2% lemongrass gel and 10% doxycycline hyclate gel as an adjunct to scaling and root planing (SRP) in treating chronic periodontitis. Method: This is a double-blind parallel arm randomized controlled study. Forty subjects were randomly divided into Group A and B for 2% lemongrass gel and 10% doxycycline hyclate gel, respectively. The clinical assessments of Gingival Index (GI), Plaque Index (PI), Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL) together with microbial colony counts for Porphyromonas gingivalis, Actinomyces naeslundii, and Prevotella intermedia were done at baseline, 1st month, and 3rd month follow-ups. Results: The results showed there was a significant reduction in the mean scores of GI, PPD, and CAL clinical indices from baseline to the 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Similarly, there was significant reduction in mean CFU scores for all periodontal pathogens from baseline to 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Conclusions: It could be concluded that the local delivery of 2% lemongrass gel as an adjunct to scaling and root planing is effective and comparable to 10% doxycycline gel in the treatment of chronic periodontitis.

Bioactivity assessment of essential oils of Cymbopogon species using a network pharmacology approach

Essential oils of Cymbopogon species have wide commercial applications in fragrance, perfumery, and pharmaceuticals as they exhibit a horizon of bioactivities. Here, essential oils of C. flexuosus and C. martinii were analysed to identify bioactive constituents and bioactivities using a network pharmacology approach. Essential oils were isolated using hydro-distillation in a mini Clevenger apparatus. Analysis of essential oils by GC-MS revealed 20 and 15 chemical constituents in C. flexuosus and C. martinii, respectively. An ingredient-target protein-pathway network was constructed comprising 10 oil constituents (citral, geraniol, geranyl acetate, limonene, linalool, α-terpineol, borneol, α-pinene, myrcene, and n-decanol), 14 target proteins, 51 related pathways, and 108 connections. Analyses of the network showed geraniol, geranyl acetate, limonene, linalool, and citral as major active constituents. A core sub-network constructed from the ingredient-target protein-pathway network revealed bioactivities including anti-cancer, anti-inflammatory and neuroprotective. The protein association network pointed out the major target proteins viz., THRB, FXR, ALOX15, and TSHR and pathways like metabolic, and neuroactive ligand-receptor interaction pathways of essential oil constituents. The target proteins and pathways provided insights into the mechanism of action of bioactive constituents. Based on the results of the study, geraniol was correlated with neuroprotective, citral to chemo-preventive, and limonene to anti-inflammatory activities. Thus, the study offers a new way for the assessment of the bioactivities of Cymbopogon species essential oils leading to the development of new biomedicines.

Citral inhibits the nociception in the rat formalin test: Effect of metformin and blockers of opioid receptor and the NO-cGMP-K+ channel pathway

The objective of the present study was to scrutinize the effect of nitric oxide (NO), cGMP, potassium channel blockers and metformin on the citral-produced peripheral antinociception. The rat paw 1% formalin test was used to assess nociception and antinociception. Rats were treated with local peripheral administration of citral (10-100 µg/paw). The antinociception of citral (100 µg/paw) was evaluated with and without the local pretreatment of naloxone, NG-L-nitro-arginine methyl ester (L-NAME, a NO synthesis inhibitor), 1H-(1,2,4)-oxadiazolo(4,2-a)quinoxalin-1-one (ODQ, a soluble guanylyl cyclase inhibitor), metformin, opioid receptors antagonists, and K+ channel blockers. Injection of citral in the rat paw significantly decreased the nociceptive effect of formalin administration during the two phases of the test. Local pretreatment of the paws with L-NAME and ODQ did not reduced the citral-induced antinociception. Glipizide or glibenclamide (Kir6.1-2; ATP-sensitive K+ channel blockers), tetraethylammonium or 4-aminopyridine (KV; voltage-gated K+ channel blockers) or charybdotoxin (KCa1.1; big conductance calcium-activated K+ channel blocker) or apamin (KCa2.1-3; small conductance Ca2+-activated K+ channel antagonist), or metformin, but not the opioid antagonists, reduced the antinociception of citral. Citral produced peripheral antinociception during both phases of the formalin test. These effects were due to the activation of K+ channels and a biguanide-dependent mechanism.

Citral alleviates peptidoglycan-induced inflammation and disruption of barrier functions in porcine intestinal epithelial cells

Peptidoglycan (PGN) is a major polymer in bacterial cell walls and may constrain gut functionality and lower intestinal efficiencies in livestock. Citral has been reported to exhibit antibacterial and anti-inflammatory biological activities, improving the gastrointestinal function of swine. However, the protective effect of citral against PGN-elicited cellular responses and possible underlying mechanisms are unknown. In this study, the porcine jejunal epithelial cell line (IPEC-J2) was challenged with PGN from Staphylococcus aureus (S. aureus) or Bacillus subtilis (B. subtilis) to explore PGN-induced inflammatory responses. Our data showed that the inflammatory response stimulated by PGN from harmful bacteria (S. aureus) was more potent than that from commensal bacteria (B. subtilis) in IPEC-J2 cells. Based on the inflammatory model by PGN from S. aureus, it was demonstrated that PGN could significantly induce inflammatory cytokine production and influence nutrient absorption and barrier function in a dose-dependent manner. However, the PGN-mediated immune responses were remarkably suppressed by citral. In addition, citral significantly attenuated the effect of PGN on the intestine nutrient absorption and barrier function. The expression of TLR2 was strongly induced by PGN stimulation, which was suppressed by citral. All data nominated that citral downregulated PGN-induced inflammation via TLR2-mediated activation of the NF-κB signaling pathway in IPEC-J2 cells. Furthermore, the results also indicate that the PGN degradation through the inclusion of enzymes (e.g., muramidase) as well as the inclusion of citral for attenuating inflammation may improve pig gut health and functionality.

Essential Oil of Cymbopogon Citratus Grown in Umuahia: A Viable Candidate for Anti-Inflammatory and Antioxidant Therapy

The essential oils of Cymbopogon citratus (EOCC) has found use in medicine, food and chemical industry. This study attempts to provide evidence of its suitability for antioxidant and anti-inflammatory therapy. Total phenol and total flavonoid of EOCC was 49.83±0.39mg GAE/g of extract and 352.82±3.45 µg QEC/g of extract respectively. Gas chromatography-mass spectrometry (GC-MS) analysis of its essential oil (EOCC) showed 25 peaks with myrcenyl acetate (9.703%), caryophyllene (8.997%), citronella (6.383%) been the most abundant. The in vitro anti-inflammatory assay using human red blood cell (HRBC) membrane stabilization shows that at 200µg/mL, the percentage inhibition of EOCC was significantly higher compared to diclofenac both for heat-induced and hypotonic induced haemolysis. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays showed a comparable and dose-dependent increase from 50 to 400 μg/mL in relation to vitamin C. Half maximal inhibitory concentration (IC50) of EOCC (73.16±12.89 μg/mL and 656.01±0.01 μmol Fe (II)/L) was remarkably higher compared to that of vitamin C (69.09±4.52 μg/mL and 246.79±0.01 μmol Fe (II)/L) both for DPPH and FRAP assays respectively. In conclusion, results from this study establish preliminary evidence on the therapeutic potential of EOCC in managing inflammation and oxidative stress caused by free radicals.

Role of Herbal Teas in Regulating Cellular Homeostasis and Autophagy and Their Implications in Regulating Overall Health

Tea is one of the most popular and widely consumed beverages worldwide, and possesses numerous potential health benefits. Herbal teas are well-known to contain an abundance of polyphenol antioxidants and other ingredients, thereby implicating protection and treatment against various ailments, and maintaining overall health in humans, although their mechanisms of action have not yet been fully identified. Autophagy is a conserved mechanism present in organisms that maintains basal cellular homeostasis and is essential in mediating the pathogenesis of several diseases, including cancer, type II diabetes, obesity, and Alzheimer’s disease. The increasing prevalence of these diseases, which could be attributed to the imbalance in the level of autophagy, presents a considerable challenge in the healthcare industry. Natural medicine stands as an effective, safe, and economical alternative in balancing autophagy and maintaining homeostasis. Tea is a part of the diet for many people, and it could mediate autophagy as well. Here, we aim to provide an updated overview of popular herbal teas’ health-promoting and disease healing properties and in-depth information on their relation to autophagy and its related signaling molecules. The present review sheds more light on the significance of herbal teas in regulating autophagy, thereby improving overall health.

Metabolomic and Pharmacologic Insights of Aerial and Underground Parts of Glycyrrhiza uralensis Fisch. ex DC. for Maximum Utilization of Medicinal Resources

The roots of Glycyrrhiza spp. have been utilized in Traditional Chinese medicine (TCM) for thousands of years. Non-traditional (aerial) parts constitute a large portion of the biomass of Glycyrrhiza plants and are mostly discarded after harvesting the roots and rhizomes. Through comparative phytochemical and anti-inflammatory activity analyses, this study explored the potential benefits of the aerial parts of Glycyrrhiza uralensis Fisch. ex DC. as medicinal materials. First, a combined approach based on GC/MS and UHPLC-ESI-QTof MS analysis was adopted for the identification and quantitative examination of medicinally important compounds from G. uralensis. Additionally, a bioassay-guided fractioning of ethanolic extracts of G. uralensis leaf material was performed and its anti-inflammatory activity was tested. The aerial portion of G. uralensis was rich in medicinally important compounds. Two compounds (henicosane-1 and decahydroisoquinoline-2) were found to exert a significant anti-inflammatory effect, inhibiting the release of pro-inflammatory mediators (NO and PGE2) and cytokines (IL-1β, IL6, and TNF-α), without exerting cytotoxic effects. Moreover, both compounds down-regulated iNOS and COX-2 mRNA expression. These results suggest that non-traditional parts of G. uralensis are suitable sources of bioactive metabolites that can be explored for medicinal purposes.

Citral-Containing Essential Oils as Potential Tyrosinase Inhibitors: A Bio-Guided Fractionation Approach

Excessive melanin production causes serious dermatological conditions as well as minor aesthetic problems (i.e., freckles and solar lentigo). The downregulation of tyrosinase is a widespread approach for the treatment of such disorders, and plant extracts have often proven to be valuable sources of tyrosinase inhibitors. Citral (a mixture of neral and geranial) is an important fragrance ingredient that has shown anti-tyrosinase potential. It is highly concentrated in the essential oils (EOs) of Cymbopogon schoenanthus (L.) Spreng., Litsea cubeba (Lour.) Pers., Melissa officinalis L., and Verbena officinalis L. However, only L. cubeba EO has been investigated for use as a potential skin-whitening agent. This work evaluates the in vitro tyrosinase inhibitory activity of these EOs and studies, using bio-assay oriented fractionation, whether their differing chemical compositions influence the overall EO inhibitory activities via possible synergistic, additive, and/or competitive interactions between EOs components. The inhibitory activity of C. schoenanthus EO and that of M. officinalis EOs, with negligible (+)-citronellal amounts, were in-line with their citral content. On the other hand, L. cubeba and V. officinalis EOs inhibited tyrosinase to considerably greater extents as they contained β-myrcene, which contributed to the overall EO activities. Similar observations were made for M. officinalis EO, which bears high (+)-citronellal content which increased citral activity.

In vitro effects of citral on the human myometrium: Potential adjunct therapy to prevent preterm births

BACKGROUND

Premature infants contribute to infant morbidity and mortality especially in low resource settings. Information on tocolytic and/or anti-inflammatory effects of several plant extracts, such as citral, could help prevent preterm birth cases and reduce the number of preterm infants. The aim of this study was to evaluate the in vitro tocolytic and anti-inflammatory effect of citral on myometrial tissues of the human uterus.

METHODS

Myometrial samples from uteri obtained after hysterectomy were used in functional tests to evaluate the inhibitory effect of citral on PGF-2α induced contractions. The intracellular cyclic adenosine monophosphate (cAMP) levels generated in response to citral in human myometrial homogenates were measured by ELISAs. Forskolin was used as a positive control. The anti-inflammatory effect of citral was determined through the measurement of two pro-inflammatory cytokines, tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and the anti-inflammatory cytokine IL-10, in human myometrial explants stimulated with lipopolysaccharide (LPS).

RESULTS

Citral was able to induce a significant inhibition of PGF-2α induced contractions at the highest concentration level (p < .05). Citral caused a concentration-dependent increase in myometrial cAMP levels (p < .05) and a concentration-dependent decrease in LPS-induced TNFα and IL-1β production, while IL-10 production increased significantly (p < .05). The anti-inflammatory and tocolytic effects induced by citral could be associated with an increase in cAMP levels in human myometrial samples.

CONCLUSION

These properties place citral as a potentially safe and effective adjuvant agent in preterm birth cases, an obstetric and gynecological problem that requires urgent attention.

Citral inhibits N-nitrosodiethylamine-induced hepatocellular carcinoma via modulation of antioxidants and xenobiotic-metabolizing enzymes

Hepatocellular carcinoma (HCC) ranks the sixth position among various cancers worldwide. Recent research shows that natural and dietary compounds possess many therapeutic effects. Citral is a monoterpene aldehyde that contains geranial and neral. The present study was considered to study the role of citral against N-nitrosodiethylamine (NDEA)-induced HCC via modulation of antioxidants and xenobiotic-metabolizing enzymes in vivo. NDEA-alone-administered group II animals profoundly showed increased tumor incidence, reactive oxygen species, liver marker enzyme levels, serum bilirubin levels, tumor markers of carcinoembryonic antigen, α-fetoprotein, proliferative markers of argyrophilic nucleolar organizing regions, proliferating cell nuclear antigen (PCNA) expressions, phase I xenobiotic-metabolic enzymes and simultaneously decreased antioxidants, and phase II enzymes levels. Citral (100 mg/kg b.w.) treatment significantly reverted the levels in group III cancer-bearing animals when compared to group II cancer-bearing animals. In group IV animals, citral-alone administration did not produce any adverse effect during the experimental condition. Based on the results, citral significantly inhibits the hepatocellular carcinogenesis through restoring the antioxidants and phase II xenobiotic-enzyme levels; thereby, it strongly proves as an antiproliferative agent against rat HCC.

Citral Inhibits the Inflammatory Response and Hyperalgesia in Mice: The Role of TLR4, TLR2/Dectin-1, and CB2 Cannabinoid Receptor/ATP-Sensitive K+ Channel Pathways

Citral ((2E)-3,7-dimethylocta-2,6-dienal), a bioactive component of lemongrass, inhibits oxidant activity, nuclear factor kappa B (NF-κB) activation, and cyclooxygenase-2 (COX-2) expression, even as it activates peroxisome proliferator-activated receptor (PPAR)-α and γ. Additionally, citral produces long-lasting inhibition of transient receptor potential (TRP) channels that are found in sensory neurons, such as TRPV1-3 and TRPM8, while it transiently blocks TRPV4 and TRPA1. Here, the effect of citral in experimental models of acute inflammation and hyperalgesia in mice, and the underlying citral mechanisms of action were investigated. ADMET properties and molecular targets were predicted using the online server. The immunomodulatory and antihyperalgesic effects of citral were evaluated, using mechanical and thermal stimuli, at different time-points on carrageenan, lipopolysaccharides (LPS), and zymosan-induced paw edema and hyperalgesia in mice. ADMET analysis ensures that the citral has not violated Lipinski's rule of five, indicating its safety consumption, and molecular target prediction software identified that citral is a potential fatty acid amide hydrolase (FAAH) inhibitor. Oral treatment with citral (50-300 mg/kg) significantly inhibited carrageenan-induced paw edema and thermal allodynia. Furthermore, citral modulated the inflammation induced by LPS and zymosan, toll-like receptor (TLR) 4, and TLR2/dectin-1 ligands, respectively. Moreover, pretreatment with cannabinoid receptor type 2 (CB2R) antagonists and ATP-sensitive K⁺ channel inhibitor, but not with a cannabinoid receptor type 1 (CB1R) antagonist, significantly reversed the anti-inflammatory effect of citral. Intriguingly, citral did not cause any relevant action in the central nervous system, and it was safe when assessed in a 14 day toxicity assay in male mice. Therefore, citral constitutes a promising, innovative, and safe molecule for the management of immunoinflammatory conditions and pain states.

In silico, in-vitro and in vivo screening of biological activities of citral

Citral, one of the main components of lemongrass oil (65-85%), is known to possess various medicinal properties like enhancing skin health and vision-improvement. It also acts as flavoring agent, used in perfumes and skin care products. The objective of this work was to elucidate the biological properties of citral at molecular level using an integrated in silico, in vitro and in vivo approaches. To elucidate this in silico molecular docking studies were performed with in vitro validation by DPPH scavenging activity, MTT assays, enzymatic assays and Chorio Allantoic Membrane (CAM) assay. The in silico analysis demonstrated the potential binding of citral with PPARγ ligand binding domain and vascular endothelial growth factor receptors (VEGFR-1 and VEGFR-2). Citral is already a proven anti-oxidant which is further confirmed by increased DPPH inhibition with increased citral concentration (IC50: 6.9 ± 1.68 μg/ml, p < 0.05). The results demonstrated that citral protect yeast cells from cytotoxic effects of hydrogen peroxide and also increase the activities of antioxidant enzymes like GST, SOD and LPO. It was also demonstrated to be cytotoxic to cancerous HeLa cells (IC50: 3.9 ± 0.38 μM, p < 0.01) and was found anti-angiogenic by CAM assay. This study highlights many important pharmaceutical properties of citral which can be explored further to increase its industrial applications.

Targets and pathways involved in the antitumor activity of citral and its stereo-isomers

This review provides a comprehensive analysis of the anticancer potential of the natural product citral (CIT) found in many plants and essential oils, and extensively used in the food and cosmetic industry. CIT is composed of two stereoisomers, the trans-isomer geranial being a more potent anticancer compound than the cis-isomer neral. CIT inhibits cancer cell proliferation and induces cancer cell apoptosis. Its pluri-factorial mechanism of anticancer activity is essentially based on three pillars: (i) a drug-induced accumulation of reactive oxygen species in cancer cells leading to an oxidative burst and DNA damages, (ii) a colchicine-like inhibition of tubulin polymerization and promotion of microtubule depolymerization, associated with an inhibition of the microtubule affinity-regulating kinase MARK4, and (iii) a potent inhibition of the aldehyde dehydrogenase isoform ALDH1A3 which is associated with cancer stem cell proliferation and chemoresistance. This unique combination of targets and pathways confers a significant anticancer potential. However, the intrinsic potency of CIT is limited, mainly because the drug is not very stable and has a low bioavailability and it does not present a high selectivity for cancer cells versus non-tumor cells. Stable formulations of CIT, using cyclodextrins, biodegradable polymers, or various nano-structured particles have been designed to enhance the bioavailability, to increase the effective doses window and to promote the anticancer activity. The lack of tumor cell selectivity is more problematic and limits the use of the drug in cancer therapy. Nevertheless, CIT offers interesting perspectives to design more potent analogues and drug combinations with a reinforced antitumor potential.

Phenolic Compounds and Ginsenosides in Ginseng Shoots and Their Antioxidant and Anti-Inflammatory Capacities in LPS-Induced RAW264.7 Mouse Macrophages

We conducted this study for the first time to evaluate changes in the composition and contents of phenolic compounds and ginsenosides in ginseng shoot extracts (GSEs) prepared with different steaming times (2, 4, and 6 h) at 120 °C, as well as their antioxidant and anti-inflammatory activities in lipopolysaccharide (LPS)-induced RAW264.7 mouse macrophages (RAW264.7 cells). The results show that total phenol and flavonoid contents were both significantly higher in steamed versus raw GSEs, and the same trend was found for 2,2'-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2'-azobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) scavenging capacities. Among the 18 ginsenosides quantified using high-performance liquid chromatography (HPLC) with the aid of pure standards, polar ginsenosides were abundant in raw GSEs, whereas less-polar or rare ginsenosides appeared after steaming at 120 °C and increased with steaming time. Furthermore, steamed GSEs exhibited a greater ability to inhibit the production of inflammatory mediators and pro-inflammatory cytokines, such as nitric oxide (NO), interleukin (IL)-6, and tumor necrosis factor (TNF)-α in LPS-induced RAW264.7 cells at the same concentration. Relative expression levels of inducible nitric oxide synthase (iNOS), IL-6, TNF-α, and cyclooxygenase-2 (COX-2) mRNAs were attenuated by the GSEs, probably due to the enrichment of less-polar ginsenosides and enhanced antioxidant activity in steamed GSEs. These findings, combined with correlation analysis, showed that less-polar ginsenosides were major contributors to the inhibition of the overproduction of various inflammatory factors, while the inhibitory effects of total phenols and total flavonoids, and their antioxidant abilities, are also important.

Induction of programmed cell death in Trypanosoma cruzi by Lippia alba essential oils and their major and synergistic terpenes (citral, limonene and caryophyllene oxide)

Background

Chagas Disease caused by Trypanosoma cruzi infection, is one of the most important neglected tropical diseases (NTD), without an effective therapy for the successful parasite eradication or for the blocking of the disease’s progression, in its advanced stages. Due to their low toxicity, wide pharmacologic spectrum, and potential synergies, medicinal plants as Lippia alba, offer a promising reserve of bioactive molecules. The principal goal of this work is to characterize the inhibitory properties and cellular effects of the Citral and Carvone L. alba chemotype essential oils (EOs) and their main bioactive terpenes (and the synergies among them) on T. cruzi forms.

Methods

Twelve L. alba EOs, produced under diverse environmental conditions, were extracted by microwave assisted hydrodistillation, and chemically characterized using gas chromatography coupled mass spectrometry. Trypanocidal activity and cytotoxicity were determined for each oil, and their major compounds, on epimastigotes (Epi), trypomastigotes (Tryp), amastigotes (Amas), and Vero cells. Pharmacologic interactions were defined by a matrix of combinations among the most trypanocidal terpenes (limonene, carvone; citral and caryophyllene oxide). The treated cell phenotype was assessed by fluorescent and optic microscopy, flow cytometry, and DNA electrophoresis assays.

Results

The L. alba EOs displayed significant differences in their chemical composition and trypanocidal performance (p = 0.0001). Citral chemotype oils were more trypanocidal than Carvone EOs, with Inhibitory Concentration 50 (IC₅₀) of 14 ± 1.5 μg/mL, 22 ± 1.4 μg/mL and 74 ± 4.4 μg/mL, on Epi, Tryp and Amas, respectively. Limonene exhibited synergistic interaction with citral, caryophyllene oxide and Benznidazole (decreasing by 17 times its IC₅₀) and was the most effective and selective treatment. The cellular analysis suggested that these oils or their bioactive terpenes (citral, caryophyllene oxide and limonene) could be inducing T. cruzi cell death by an apoptotic-like mechanism.

Conclusions

EOs extracted from L. alba Citral chemotype demonstrated significant trypanocidal activity on the three forms of T. cruzi studied, and their composition and trypanocidal performance were influenced by production parameters. Citral, caryophyllene oxide, and limonene showed a possible induction of an apoptotic-like phenotype. The best selective anti-T. cruzi activity was achieved by limonene, the effects of which were also synergic with citral, caryophyllene oxide and benznidazole.

Solvent Extraction and Identification of Active Anticariogenic Metabolites in Piper cubeba L. through ¹H-NMR-Based Metabolomics Approach

The aim of this study was to determine the effects of different solvents for extraction, liquid⁻liquid partition, and concentrations of extracts and fractions of Piper cubeba L. on anticariogenic; antibacterial and anti-inflammatory activity against oral bacteria. Furthermore, ¹H-Nuclear Magnetic Resonance (NMR) coupled with multivariate data analysis (MVDA) was applied to discriminate between the extracts and fractions and examine the metabolites that correlate to the bioactivities. All tested bacteria were susceptible to Piper cubeba L. extracts and fractions. Different solvents extraction, liquid⁻liquid partition and concentrations of extracts and fractions have partially influenced the antibacterial activity. MTT assay showed that P. cubeba L. extracts and fractions were not toxic to RAW 264.7 cells at selected concentrations. Anti-inflammatory activity evaluated by nitric oxide (NO) production in lipopolysaccharide (LPS) stimulated cells showed a reduction in NO production in cells treated with P. cubeba L. extracts and fractions, compared to those without treatment. Twelve putative metabolites have been identified, which are (1) cubebin, (2) yatein, (3) hinokinin, (4) dihydrocubebin, (5) dihydroclusin, (6) cubebinin, (7) magnosalin, (8) p-cymene, (9) piperidine, (10) cubebol, (11) d-germacrene and (12) ledol. Different extraction and liquid⁻liquid partition solvents caused separation in principal component analysis (PCA) models. The partial least squares (PLS) models showed that higher anticariogenic activity was related more to the polar solvents, despite some of the active metabolites also present in the non-polar solvents. Hence, P. cubeba L. extracts and fractions exhibited antibacterial and anti-inflammatory activity and have potential to be developed as the anticariogenic agent.

The anti-inflammatory effect of Agaricus brasiliensis is partly due to its linoleic acid content

For hundreds of years mushrooms have been used as functional food for health. The basidiomycete Agaricus brasiliensis (A. brasiliensis) is famous for the medicinal properties of its beta glucans and of its antioxidants. Most researchers have studied polysaccharides from A. brasiliensis for their anti-inflammatory activity. However, active compounds from this mushroom have not yet been studied for the inactivation of NO inhibitory activity. The present study aimed to find the active compounds from A. brasiliensis for their NO inhibitory activity related inflammatory activity. This study found that linoleic acid isolated from A. brasiliensis inhibited NO production and suppressed the expression of pro-inflammatory cytokines including TNF-α, IL-6, IL-1β, and NOS2 in RAW 264.7 cells. Linoleic acid also suppressed the expression of NF-κB subunit p50 and restored PPARα. This leads to the conclusion that linoleic acid from A. brasiliensis could reduce NO production and inflammatory activity in RAW 264.7 cells by the inhibition of p50 and via the activation of PPARα. This study suggests that linoleic acid present in A. brasiliensis could play a role in the prevention of inflammatory diseases for which this edible mushroom is already known.

Characterization and toxicity of citral incorporated with nanostructured lipid carrier

The nanoparticle as a cancer drug delivery vehicle is rapidly under investigation due to its promising applicability as a novel drug delivery system for anticancer agents. This study describes the development, characterization and toxicity studies of a nanostructured lipid carrier (NLC) system for citral. Citral was loaded into the NLC using high pressure homogenization methods. The characterizations of NLC-citral were then determined through various methods. Based on Transmission Electron Microscope (TEM) analysis, NLC-Citral showed a spherical shape with an average diameter size of 54.12 ± 0.30 nm and a polydipersity index of 0.224 ± 0.005. The zeta potential of NLC-Citral was −12.73 ± 0.34 mV with an entrapment efficiency of 98.9 ± 0.124%, and drug loading of 9.84 ± 0.041%. Safety profile of the formulation was examined via in vitro and in vivo routes to study its effects toward normal cells. NLC-Citral exhibited no toxic effects towards the proliferation of mice splenocytes. Moreover, no mortality and toxic signs were observed in the treated groups after 28 days of treatment. There were also no significant alterations in serum biochemical analysis for all treatments. Increase in immunomodulatory effects of treated NLC-Citral and Citral groups was verified from the increase in CD4/CD3 and CD8/CD3 T cell population in both NLC-citral and citral treated splenocytes. This study suggests that NLC is a promising drug delivery system for citral as it has the potential in sustaining drug release without inducing any toxicity.

Essential oil of Cymbopogon citratus (lemongrass) and geraniol, but not citral, promote gastric healing activity in mice

Cymbopogon citratus, popularly known as lemongrass, is used for the treatment of gastric, nervous and hypertensive disorders, in addition to its use in the food and pharmaceutical industries. This study evaluated the gastroprotective and gastric healing effect of essential oil of C. citratus (EOCC), citral and geraniol at doses of 1-100 mg/kg (p.o) on acute ethanol-induced ulcer and chronic acetic acid-induced ulcer. Histological and histochemical evaluation was also performed, as well as the in vitro evaluation of the effects of these phytochemicals on H⁺/K⁺-ATPase activity. In the ethanol-induced gastric ulcer, the minimum effective oral dose of EOCC, citral and geraniol were 10, 100 and 3 mg/kg, reducing the ulcer area by 51.67%, 96.57% and 55.74%, respectively, compared to vehicle group (25.82 ± 3.59 mm²). Moreover, EOCC (10 mg/kg, p.o) and geraniol (3 mg/kg), but not citral (100 mg/kg), accelerated the gastric healing process by 34.52 and 80.57%, compared to acetic-acid ulcerated group treated with vehicle (36.04 ± 1.03 mm²). These healing effects were confirmed histologically by the contraction of the ulcer base and by the enhancement on mucin staining in slices of ulcer site from mice treated with EOCC or geraniol. Interestingly, EOCC and citral at 100 μg/ml inhibited the H⁺/ K⁺-ATPase activity by 28.26% and 44.36%, whereas geraniol did not change this parameter. Together, these findings confirm the gastroprotective and healing gastric ulcer effects of essential oil from aerial parts of C. citratus and added the information that geraniol, but not citral, promotes healing effects on installed ulcers.

In vitro anti-inflammatory activity of spherical silver nanoparticles and monodisperse hexagonal gold nanoparticles by fruit extract of Prunus serrulata: a green synthetic approach

Recently, green metal nanoparticles have received global attention owing to their economical synthesis, biocompatible nature, widespread biomedical and environmental applications. Current study demonstrates a sustainable approach for the green synthesis of silver nanoparticles (P-AgNPs) and gold nanoparticles (P-AuNPs) from P. serrulata fresh fruit extract. The silver and gold nanoparticles were synthesized in a very rapid, efficient and facile manner, within 50 min and 30 s at 80 °C, respectively. The nanoparticles were characterized by using visual observation, UV-Vis, FE-TEM, EDX, elemental mapping, FT-IR, XRD and DLS, which confirmed the formation of monodispersed, crystalline and stable nanoparticles. Further, we explored these nanoparticles for anti-inflammatory activity through inhibition of downstream NF-κB activation in macrophages (RAW264.7). We demonstrated that the nanoparticles reduced expression of inflammatory mediators such as nitric oxide (NO), prostaglandin E2 (PEG₂), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was attenuated in lipopolysaccharide (LPS)-induced RAW264.7 cells. Furthermore, nanoparticles significantly suppressed LPS-induced activation of NF-κB signalling pathway via p38 MAPK in RAW 264.7 cells. To the best of our knowledge, this is the first report on the efficient green synthesis of P-AgNPs and P-AuNPs using P. serrulata fresh fruit extract and its in vitro anti-inflammatory effects. Collectively, our results suggest that P. serrulata fresh fruit extract is a green resource for the eco-friendly synthesis of P-AgNPs and P-AuNPs, which further can be utilized as a novel therapeutic agent for prevention and cure of inflammation due to their biocompatible nature.

Investigation of molecular mechanism of recognition between citral and MARK4: A newer therapeutic approach to attenuate cancer cell progression

Microtubule affinity regulating kinase 4 (MARK4) is a member of AMP-activated protein kinase, found to be involved in apoptosis, inflammation and many other regulatory pathways. Since, its aberrant expression is directly associated with the cell cycle and thus cancer. Therefore, MARK4 is being considered as a potential drug target for cancer therapy. Here, we investigated the mechanism of inhibition of MARK4 activity by citral. Docking studies suggested that citral effectively binds to the active site cavity, and complex is stabilized by several interactions. We further performed molecular dynamics simulation of MARK4-citral complex under explicit water condition for 100ns and observed that binding of citral to MARK4 was quite stable. Fluorescence binding studies suggested that citral strongly binds to MARK4 and thereby inhibits its enzyme activity which was measured by the kinase inhibition assay. We further performed MTT assay and observed that citral inhibits proliferation of breast cancer cell line MCF-7. This work provides a newer insight into the use of citral as novel cancer therapeutics through the MARK4 inhibition. Results may be employed to design novel therapeutic molecule using citral as a scaffold for MARK4 inhibition to fight related diseases.

Anti-inflammatory and anti-oxidant effects of Cardamom (Elettaria repens (Sonn.) Baill) and its phytochemical analysis by 4D GCXGC TOF-MS

Elleteria repens is a large cardamom used in the culinary preparations. In the present study, we have evaluated in vitro antioxidant and free radical scavenging activities E. repens hexane extract (ERH) exhibited DPPH and metal chelating activity with IC₅₀ values of 464±28.3μg/ml, 199±7.2μg/ml whereas the reducing power and antioxidant activities are found to be 289±14.6 AAE/mg, 468±22.7 GAE/mg. The observed antioxidant activities could be correlated with metabolites such as polyphenol, flavonoid, and terpenoid group of compounds identified in hexane fraction of E. repens by 4D GCXGC TOF-MS. Further ERH was evaluated for its protective properties against macromolecules such as DNA, protein and lipid damage. The extract showed protection against H₂O₂ induced DNA damage and inhibited AAPH induced protein oxidation and lipid peroxidation. Moreover, ERH administration to rats at 50 and 100mg/kg inhibited carrageenan-induced paw edema, and down-regulated cytokines such as COX-2, IL-6, and TNF-α and inhibited i-NOS mediated NO generation. E. repens also exhibited antioxidant effects by restoring SOD, catalase, GSH levels and inhibited lipid peroxidation in carrageenan challenged rats. Overall, the results suggest that E. repens may be useful in combating inflammation and oxidative stress.

Cytotoxicity of citral against melanoma cells: The involvement of oxidative stress generation and cell growth protein reduction

Citral is a natural compound that has shown cytotoxic and antiproliferative effects on breast and hematopoietic cancer cells; however, there are few studies on melanoma cells. Oxidative stress is known to be involved in all stages of melanoma development and is able to modulate intracellular pathways related to cellular proliferation and death. In this study, we hypothesize that citral exerts its cytotoxic effect on melanoma cells by the modulation of cellular oxidative status and/or intracellular signaling. To test this hypothesis, we investigated the antiproliferative and cytotoxic effects of citral on B16F10 murine melanoma cells evaluating its effects on cellular oxidative stress, DNA damage, cell death, and important signaling pathways, as these pathways, namely, extracellular signal-regulated kinases 1/2 (ERK1/2), AKT, and phosphatidylinositol-3 kinase, are involved in cell proliferation and differentiation. The p53 and nuclear factor kappa B were also investigated due to their ability to respond to intracellular stress. We observed that citral exerted antiproliferative and cytotoxic effects in B16F10; induced oxidative stress, DNA lesions, and p53 nuclear translocation; and reduced nitric oxide levels and nuclear factor kappa B, ERK1/2, and AKT. To investigate citral specificity, we used non-neoplastic human and murine cells, HaCaT (human skin keratinocytes) and NIH-3T3 cells (murine fibroblasts), and observed that although citral effects were not specific for cancer cells, non-neoplastic cells were more resistant to citral than B16F10. These findings highlight the potential clinical utility of citral in melanoma, with a mechanism of action involving the oxidative stress generation, nitric oxide depletion, and interference in signaling pathways related to cell proliferation.

Biological properties of citral and its potential protective effects against cytotoxicity caused by aspirin in the IEC-6 cells

Citral, 3,7-dimethyl-2,6-octadienal, is a key component of several essential oils extracted from lemon-scented herbal plants. The present study was designed to investigate the antioxidant activities of citral and assess its possible protective effects against aspirin-induced toxicity in vitro. We used IEC-6 cells (rat small intestine epithelial cells). The antioxidant activities were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene/linoleic acid and Ferric reducing antioxidant power (FRAP). Cytotoxicity was evaluated by cell viability, anti-oxidant enzyme activities, malondialdehyde (MDA) production and by the expression of MAPKs (Mitogen-Activated Protein Kinases) pathways. According to results, citral showed an important antioxidant activity. It inhibited the oxidation of linoleic acid, a moderate DPPH was found and it showed a Ferric reducing antioxidant potential with an EC₅₀ value of 125±28.86μg/mL. Then, the co-treatment of aspirin with citral significantly decreased the aspirin-induced cell death, and the MDA level. It modulated the superoxide dismutase (SOD) and glutathione (GSH) activities. Also, the activation of MAPKs was attenuated by citral. These findings suggest that citral can protect IEC-6 cells against aspirin-induced oxidative stress that may help to discover new chemicals out of natural antioxidant substances.

Anti-Inflammatory Activity of the Essential Oil Citral in Experimental Infection with Staphylococcus aureus in a Model Air Pouch

This study proposes to implement an alternative and effective strategy for local treatment of disease provoked by S. aureus. For the analysis of possible anti-inflammatory activity of essential oil, after establishing an air pouch model, 48 male mice of Balb/c were treated, infected, and euthanized at 4 and 8 h. Thus, the total and differential white blood cells were counted in the animal's blood, and cytokines IL-1β, IL-6, and TNF-α were titrated using ELISA in the air pouch lavage. Moreover, TNF-α, IL-1β, and IL-6 gene expression was analyzed through an RT-qPCR array, and S. aureus was quantified using qPCR. Our results, p < 0.05, showed that EOC reduced the quantity of microorganisms. The group of mice treated with essential oil citral showed a significant decrease in TNF-α levels in tests demonstrating anti-inflammatory activity. There is no data about the mutual influence of the air pouch model, essential oil citral, and S. aureus. Thus, considering the interaction of these variables and the anti-inflammatory activity of the essential oil citral, we demonstrated, by alternative local treatment, a new antimicrobial agent that is not an antibiotic.

Hepatoprotective Effect of Citral on Acetaminophen-Induced Liver Toxicity in Mice

High doses of acetaminophen (APAP) lead to acute liver damage. In this study, we evaluated the effects of citral in a murine model of hepatotoxicity induced by APAP. The liver function markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (γGT) were determined to evaluate the hepatoprotective effects of citral. The livers were used to determine myeloperoxidase (MPO) activity and nitric oxide (NO) production and in histological analysis. The effect of citral on leukocyte migration and antioxidant activity was evaluated in vitro. Citral pretreatment decreased significantly the levels of ALT, AST, ALP, and γGT, MPO activity, and NO production. The histopathological analysis showed an improvement of hepatic lesions in mice after citral pretreatment. Citral inhibited neutrophil migration and exhibited antioxidant activity. Our results suggest that citral protects the liver against liver toxicity induced by APAP.

Influence of geography, seasons and pedology on chemical composition and anti-inflammatory activities of essential oils from Lippia multiflora Mold leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Lippia multiflora is a plant with nutritional and pharmaco-therapeutic properties that is native to central and occidental Africa. The potential effects of plants on health are associated with their chemical composition. Therefore, the present study aimed to identify chemical variations in essential oils of Lippia multiflora as a function of geographic origin and time of annual harvest to determine optimal chemical profiles for ethno-pharmacotherapeutic applications.

MATERIALS AND METHODS

Experimental plants were cultivated at Abidjan (LPA), Toumodi (LPT) and Bondoukou (LPB). Natural Lippia multiflora seeds were sourced to produce standardized plants over a period of six months. Standard plants (n=40) were re-introduced into natural plots, cultivated for 12 months and leaves were sampled monthly in a standardized fashion. Essentials oils (n=36) were then extracted from these samples by hydro-distillation according to the European Pharmacopoeia and qualitatively and quantitatively analyzed using GC/FID and GC/MS. These data were then analyzed using Principal Component Analysis (PCA). Anti-inflammatory properties were also assessed against activated macrophages in vitro.

RESULTS

The results indicated that chemical profiles and essential oil yields vary according to the location where the plants were cultivated. One essential oil chemotype corresponded to the LPA and LPT sites and one corresponded to the LPB site. Statistical analysis of the chemical profiles and monthly evolution of the three sites over a period of one year allowed assessment of variations in composition and the subsequent choice of the optimal harvest time for ethnopharmacological applications. Anti-inflammatory activity apparently correlated with chemical profiles of essential oils and the geographic origins of the plants.

CONCLUSION

The optimal harvest time was associated with the maximum yield of pharmacological compounds with the most potential interest for health.

Ginger Essential Oil Ameliorates Hepatic Injury and Lipid Accumulation in High Fat Diet-Induced Nonalcoholic Fatty Liver Disease

The objective of this study was to investigate the hepatoprotective efficacy and mechanism of action of ginger essential oil (GEO) against the development of nonalcoholic fatty liver disease (NAFLD). Mice were maintained on either a control diet or high-fat diet (HFD) supplemented with GEO (12.5, 62.5, and 125 mg/kg) or citral (2.5 and 25 mg/kg) for 12 weeks. We demonstrated that GEO and its major component (citral) lowered HFD-induced obesity in a dose-dependent manner, accompanied by anti-hyperlipidemic effects by reducing serum free fatty acid, triglyceride, and total cholesterol levels. Moreover, liver histological results showed that administration of 62.5 and 125 mg/kg GEO and 25 mg/kg citral significantly reduced hepatic lipid accumulation. Further assessment by Western blotting and investigation of the lipid metabolism revealed that hepatic protein expression of sterol regulatory element-binding protein-1c (SREBP-1c), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), and cytochrome P450 2E1 (CYP2E1) were down-regulated by GEO and citral, indicating that GEO and citral suppressed HFD-stimulated lipid biosynthesis and oxidative stress. Furthermore, GEO and citral effectively enhanced the antioxidant capacities and reduced inflammatory response in mouse liver, which exerted protective effects against steatohepatitis. Collectively, GEO and citral exhibited potent hepatoprotective effects against NAFLD induced by HFD in obese mice. Thus, GEO might be an effective dietary supplement to ameliorate NAFLD-related metabolic diseases, and citral could play a vital role in its management.

Ginger hexane extract suppresses RANKL-induced osteoclast differentiation

Osteoporosis is a debilitating disease caused by decreased bone density. Compounds with anti-osteoclastic activity, such as bisphosphonates, may help in the prevention and treatment of osteoporosis. Herein, we determined the inhibitory effects of ginger hexane extract (GHE) on receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells. The results showed that GHE (1) suppressed osteoclast differentiation and the formation of actin rings; (2) inhibited the expression of Nfatc1, a master transcriptional factor for osteoclast differentiation, in a dose-dependent manner (10-20 μg/mL); and (3) inhibited other osteoclastogenesis-related genes, such as Oscar, Dc-stamp, Trap, and Mmp9. These findings suggest that GHE may be used to prevent and treat osteoporosis by inhibiting osteoclast differentiation.

Anti-hypertensive Herbs and their Mechanisms of Action: Part I

The use of herbal therapies for treatment and management of cardiovascular diseases (CVDs) is increasing. Plants contain a bounty of phytochemicals that have proven to be protective by reducing the risk of various ailments and diseases. Indeed, accumulating literature provides the scientific evidence and hence reason d'etre for the application of herbal therapy in relation to CVDs. Slowly, but absolutely, herbal remedies are being entrenched into evidence-based medical practice. This is partly due to the supporting clinical trials and epidemiological studies. The rationale for this expanding interest and use of plant based treatments being that a significant proportion of hypertensive patients do not respond to Modern therapeutic medication. Other elements to this equation are the cost of medication, side-effects, accessibility, and availability of drugs. Therefore, we believe it is pertinent to review the literature on the beneficial effects of herbs and their isolated compounds as medication for treatment of hypertension, a prevalent risk factor for CVDs. Our search utilized the PubMed and ScienceDirect databases, and the criterion for inclusion was based on the following keywords and phrases: hypertension, high blood pressure, herbal medicine, complementary and alternative medicine (CAM), nitric oxide, vascular smooth muscle cell (VSMC) proliferation, hydrogen sulfide, nuclear factor kappa-B, oxidative stress, and epigenetics/epigenomics. Each of the aforementioned keywords was co-joined with herb in question, and where possible with its constituent molecule(s). In this first of a two-part review, we provide a brief introduction of hypertension, followed by a discussion of the molecular and cellular mechanisms. We then present and discuss the plants that are most commonly used in the treatment and management of hypertension.