Genetic toxicology evaluation of essential oil of Alpinia zerumbet and its chemoprotective effects against H(2)O(2)-induced DNA damage in cultured human leukocytes

Phytochemicals of Alpinia zerumbet: A Review

Alpinia zerumbet (Pers.) B.L.Burtt & R.M.Sm is a perennial plant of the Zingiberaceae family widely distributed in the subtropical and tropical areas of South America, Oceania, and Asia. Multiple plant parts of A. zerumbet have been traditionally used as medicinal sources, each with different clinical uses. These variations may arise from differences among the chemical components and/or accumulations of the active compounds in each part. Therefore, this review summarizes previous studies on the phytochemicals in A. zerumbet and reveals the similarities and differences among the chemical constituents of its multiple medicinal parts, including the leaves, rhizomes, fruits, seeds, and flowers. The results contribute to the scientific validation of the traditional understanding that A. zerumbet possesses different medicinal properties in each plant part. In addition, this review provides directions for further studies on the phytochemicals of this plant.

Vasorelaxant effect of Alpinia zerumbet's essential oil on rat resistance artery involves blocking of calcium mobilization

Alpinia zerumbet is a plant from the Zingiberaceae family, popularly used for hypertension treatment. Several studies have demonstrated Alpinia zerumbet vasodilator effect on conductance vessels but not on resistance vessels. Thereby, the aim of this study was to verify the vasodilator effect of the essential oil of Alpinia zerumbet (EOAz) on isolated rat resistance arteries and characterize its mechanism of action. Therefore, the effect of EOAz (3 to 3000 μg/mL) was verified in second-order branches of the mesenteric artery (SOBMA) pre-contracted by KCl and U46619. To study the mechanism of action, the influence of several inhibitors (TEA, 4-AP, Glibenclamide, Atropine, L-NAME, ODQ and indomethacin) on the vasodilator effect of EOAz was evaluated. Some protocols were also performed aiming to study the effect of EOAz on Ca2+ influx and release from intracellular storage. Furthermore, the binding energy of the main constituents with calcium channels were evaluated by molecular docking. Results showed an endothelium-independent vasorelaxant effect of EOAz on SOBMA, and only ODQ and L-NAME produced significant alteration on its pEC50. Regarding the calcium assays, contraction reduction caused by incubation with EOAz was observed in all three protocols. Hence, our results suggest that EOAz has a vasodilator effect mediated by inhibition of Ca2+ influx and release from intracellular storage, as well as an activation of the NOS/sGC pathway.

Effect of essential oil of Alpinia zerumbet on cardiovascular and autonomic function in rats with isoproterenol induced acute myocardial infarction

Alpinia zerumbet is a plant popularly used to treat hypertension and anxiety. Studies with Alpinia zerumbet demonstrate antihypertensive and vasodilator effects, among others. The objective of this study was to analyze the effect of essential oil of Alpinia zerumbet (EOAz) on cardiovascular and autonomic function in rats with isoproterenol-induced myocardial infarction. Male Wistar rats (n=32) were equally allocated into four groups: Control, ISO (150mg/kg, subcutaneous), EOAz (100mg/kg by gavage), ISO+EOAz. The rats were evaluated for cardiovascular and, autonomic parameters, electrocardiogram, and infarct size. EOAz was not able to reduce the electrocardiographic variations induced by ISO. Heart rate variability showed a decrease in sympathetic modulation on the heart in the groups treated with EOAz. The cardiopulmonary reflex induced by serotonin invoked a superior blood pressure variation at the 2 µg/kg dose in the EOAz treated groups, while the heart rate variation was significantly higher at the 16 µg/kg dose, when compared to other doses, in all groups, except EOAz+ISO. The sympathetic vagal index was higher in ISO group than in control. EOAz did not reduce the infarct size. We conclude that pretreatment with EOAz does not reverse the hemodynamic and electrocardiographic damage caused by isoproterenol but does reduce sympathetic modulation.

An overview of the chemical composition and biological activities of essential oils from Alpinia genus (Zingiberaceae)

Alpinia Roxb. is the largest genus of the Zingiberaceae family. A large number of Alpinia species has been used as food and traditional medicines. Alpinia essential oils have been studied for their chemical profiles, in which 1,8-cineole, β-pinene, α-pinene, β-myrcene, camphor, γ-terpinene, p-cymene, geraniol, α-fenchyl acetate, ocimene, methyl cinnamate, and β-caryophyllene have been found to be the major compounds. Essential oils isolated from Alpinia plants have been reported to have antimicrobial, cytotoxic, antioxidant, anti-inflammatory, anti-asthmatic, tyrosinase inhibitory, insecticidal, and larvicidal activities and slimming aromatherapy. In this review, the comprehensive information regarding the volatile components of various Alpinia plants, the bioactivities of Alpinia essential oils and their major compounds are provided.

Chemopreventive effect of troxerutin against hydrogen peroxide-induced oxidative stress in human leukocytes through modulation of glutathione-dependent enzymes

Troxerutin is a natural flavonoid present abundantly in tea, coffee, olives, wheat, and a variety of fruits and vegetables. Due to its diverse pharmacological properties, this flavonoid has aroused interest for treatment of various diseases, and consequently prompted investigation into its toxicological characteristics. The aim of this study was to evaluate the genotoxic and mutagenic effects and chemoprotective activity attributed to troxerutin using human peripheral blood leukocytes (PBLs) through several well-established experimental protocols based upon different parameters. Data demonstrated that troxerutin (100 to 1000 µM) induced no marked cytotoxic effect on PBLs after 24 hr, and did not produce strand breaks and mutagenicity. Regarding chemoprevention, this flavonoid attenuated cytotoxicity, genotoxicity, and mutagenicity initiated by hydrogen peroxide (H₂O₂) in human PBLs. Further, troxerutin demonstrated no marked cytotoxic effect on PBLs and exerted a protective effect against oxidative stress induced by H₂O₂ through modulation of GSH-dependent enzymes.

p-Methoxycinnamic Acid Diesters Lower Dyslipidemia, Liver Oxidative Stress and Toxicity in High-Fat Diet Fed Mice and Human Peripheral Blood Lymphocytes

The pursuit of cholesterol lowering natural products with less side effects is needed for controlling dyslipidemia and reducing the increasing toll of cardiovascular diseases that are associated with morbidity and mortality worldwide. The present study aimed at the examining effects of p-methoxycinnamic acid diesters (PCO-C) from carnauba (Copernicia prunifera)-derived wax on cytotoxic, genotoxic responses in vitro and on dyslipidemia and liver oxidative stress in vivo, utilizing high-fat diet (HFD) chronically fed Swiss mice. In addition, we evaluated the effect of PCO-C on the expression of key cholesterol metabolism-related genes, as well as the structural interactions between PCO-C and lecithin-cholesterol acyl transferase (LCAT) in silico. Oral treatment with PCO-C was able to reduce total serum cholesterol and low-density lipoprotein (LDL) levels following HFD. In addition, PCO-C reduced excessive weight gain and lipid peroxidation, and increased the gene expression of LCAT following HFD. Furthermore, the high affinity of the studied compound (ΔG: −8.78 Kcal/mol) towards the active sites of mutant LCAT owing to hydrophobic and van der Waals interactions was confirmed using bioinformatics. PCO-C showed no evidence of renal and hepatic toxicity, unlike simvastatin, that elevated aspartate aminotransferase (AST) levels, a marker of liver dysfunction. Finally, PCO-C showed no cytotoxicity or genotoxicity towards human peripheral blood lymphocytes in vitro. Our results suggest that PCO-C exerts hypocholesterolemic effects. The safety of PCO-C in the toxicological tests performed and the reports of its beneficial biological effects render this a promising compound for the development of new cholesterol-lowering therapeutics to control dyslipidemia. More work is needed for further elucidating PCO-C role on lipid metabolism to support future clinical studies.

The Impact of the Low Frequency of the Electromagnetic Field on Human

Recently, there has been attention and controversial debate topic about the effect of low-frequency electromagnetic fields (EMFs) on human beings. The catalyst for public awareness initiated from the first epidemiological study in 1979 that reported an association between residential EMFs exposure and the incidence of childhood leukemia. For over 40 years, many epidemiological and laboratory investigations were conducted to identify the possible biological effects of low-frequency EMF. Several studies conducted at frequencies 50/60 Hz, which related to generating of electricity from electrical appliances. Experimental studies on low-frequency EMF have provided conflicting data under specific "in vivo" and "in vitro" environments. Some original papers have reported the damaging effect on DNA molecule in EMF-exposed cells. Other studies have suggested no such damage in EMF-exposed cells. Also, the conclusions from other studies were inconclusive. These conflicting findings may attribute to the differences in the apparatus used to generate electromagnetic fields, experimental design, exposure time, genetic endpoints, and biological materials such as cell lines and animal species, strain, and age. As DNA damage is frequently a prerequisite for cancer disease, this review provided an experimental body of evidence on the effect of EMF on genetic material.

Toxicological Aspects of the Essential Oil from Cinnamodendron dinisii

The objective of this study was to determine cytotoxic activity, hemolytic activity, and to evaluate the ability of the essential oil from Cinnamodendron dinisii to induce DNA fragmentation of human lymphocytes. The essential oil was obtained by hydrodistillation. Cytotoxic activity was determined by the MTT method. Hemolytic activity was evaluated by spectrophotometric quantification of hemoglobin released by erythrocytes. Damage to lymphocyte DNA molecules was assessed by the Comet assay. The essential oil under study showed high cytotoxic activity on Vero cells (CC₅₀ = 35.72 μg/mL) and induced hemolysis in both hematocrits, besides leading to the oxidation of hemoglobin released. The genotoxic activity of C. dinisii essential oil was also observed, which induced concentration-dependent DNA fragmentation of human lymphocytes and, at 50 μL/mL, it was more active than the positive control. The essential oil from C. dinisii has a toxic action, suggesting a special attention in the application of this oil to health-promoting activities; however, among its components, there are molecules with potential for future application in anticancer therapies.

Viewpoint: A Contributory Role of Shell Ginger (Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm) for Human Longevity in Okinawa, Japan?

The longevity of the population in the Okinawa Islands of Japan has been ascribed to genetic factors and the traditional Okinawa cuisine, which is low in calories and high in plant content. This diet includes shell ginger (Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm) of the ginger family (Zingiberaceae). Due to its local popularity, Alpinia zerumbet has become the subject of a good deal of study at the University of the Ryukyus in Okinawa. Personal local experience and review of the literature now suggest that culinary shell ginger may contribute to longevity among the population in Okinawa. This is supported by its abundant phytochemical content, with antioxidant and anti-obesity properties. The major bioactive phytochemicals are dihydro-5,6-dehydrokawain (DDK; 80-410 mg g^-1 fresh weight), 5,6-dehydrokawain (DK; ≤100 mg g^-1), and essential oils, phenols, phenolic acids, and fatty acids (≤150 mg g^-1 each). Further, Alpinia zerumbet extends the lifespan in animals by 22.6%. In conclusion, culinary shell ginger may significantly contribute to human longevity in Okinawa.

Genotoxicity of carbon tetrachloride and the protective role of essential oil of Salvia officinalis L. in mice using chromosomal aberration, micronuclei formation, and comet assay

The present work was conducted to evaluate the genotoxic effect of carbon tetrachloride (CCl₄) in mouse bone marrow and male germ cells. The safety and the modulating activity of sage (Salvia officinalis L.) essential oil (SEO) against the possible genotoxic effect of CCl₄ were also evaluated. A combination of in vivo mutagenic endpoints was included: micronucleus (MN), apoptosis using dual acridine orange/ethidium bromide (AO/EB) staining, comet assay, chromosomal aberrations (CAs), and sperm abnormalities. Histological examination of testis tissues was also studied. The extracted SEO was subjected to gas chromatography-mass spectrometry (GC-MS) for identifying its chemical constituents. Safety/genotoxicity of SEO was determined after two consecutive weeks (5 days/week) from oral treatment with different concentrations (0.1, 0.2, and 0.4 mL/kg). For assessing genotoxicity of CCl₄, both acute (once) and subacute i.p. treatment for 2 weeks (3 days/week) with the concentrations 1.2 mL/kg (for acute) and 0.8 mL/kg (for subacute) were performed. For evaluating the protective role of SEO, simultaneous treatment with SEO plus CCl₄ was examined. In sperm abnormalities, mice were treated with the subject materials for five successive days and the samples were collected after 35 days from the beginning of treatment. Based on GC-MS findings, 22 components were identified in the chromatogram of SEO. The results demonstrated that the three concentrations of SEO were safe and non-genotoxic in all the tested endpoints. Negative results were also observed in bone marrow after acute and subacute treatment with CCl_4. In contrast, CCl₄ induced testicular DNA damage as evidenced by a significant increase of CAs in primary spermatocytes, sperm abnormalities, and histological distortion of testis. A remarkable reduction in these cells was observed in groups treated with SEO plus CCl₄ especially with the two higher concentrations of SEO. In conclusion, SEO is safe and non-genotoxic under the tested conditions and can modulate genetic damage and histological alteration induced by CCl₄ in the testes.

Effects of the essential oil of Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm. on healing and tissue repair after partial Achilles tenotomy in rats

Purpose:

To investigate the cellular response to injury, analyzing histopathologic changes associated with increased cellularity, degeneration and disorganization of collagen fibers.

Methods:

Thirty wistar rats were divided in two groups after partial Achilles tenotomy: the right hind paw were treated with the essential oil of Alpinia zerumbet (EOAz), diluted to 33% (0.3 mL kg-1), and the left hind paw received sunflower oil for 3, 14, 30 and 90 days. Statistical significance was determined using a Chi-square and Pearson Correlation qualitative variables test. Moreover, Mann-Whitney U-test test for comparison between different groups of the same cell, one-way ANOVA, and Tukey's test of quantitative measurement.

Results:

A decrease hyperemia (p < 0.001) was observed in the acute phase of inflammatory cell number (p < 0.001), whereas sub-acute phase was marked by significant correlation with macrophages in fibroblasts (r = 0.17, p = 0.03), with probable induction a dense and modeled tissue. At chronic phase, it was found an increase in the number of fibroblasts and a higher percentage of type I collagen fibers (78%) compared with control collagen fibers (55%).

Conclusion:

Oil of Alpinia zerumbet stimulated the process of maturation, organization and tissue repair which gave it greater resistance.

Aroma Profile and Antioxidant Activity of Essential Oil from Alpinia zerumbet

The essential oil of A. zerumbet, obtained from the leaves through steam distillation, has a distinct aroma and shows antioxidant activity. In this study, we evaluated the yields, antioxidant activity, and volatile compound composition of essential oils extracted from the leaves of A. zerumbet to better understand how these characteristics may vary among individual plants, and how they may differ with location of growth and season in which leaves are harvested. Gas chromatography–mass spectrometry (GC/MS) and principal component analysis (PCA) revealed that chemical composition in each individual plant was not affected by harvest season or growth area. Furthermore, GC/MS and antioxidant activity assays revealed that although the antioxidant activity and yield of these essential oils differed significantly between individual plants and collecting seasons, there was a strong inverse correlation between the yields of essential oils and their antioxidant activity. The yield, the major volatile compound compositions, the enantiomeric ratio of the few monoterpenes, and the antioxidant activities of A. zerumbet essential oil varied significantly among individual plants, and probably reflected the genetic variability within the species. This suggests the plausibility of selecting lineages of A. zerumbet to optimize future production of valuable essential oils.

(-)-Terpinen-4-ol changes intracellular Ca2+ handling and induces pacing disturbance in rat hearts

(-)-Terpinen-4-ol is a naturally occurring plant monoterpene and has been shown to have a plethora of biological activities. The objective of this study was to investigate the effects of (-)-terpinen-4-ol on the rat heart, a key player in the control and maintenance of arterial blood pressure. The effects of (-)-terpinen-4-ol on the rat heart were investigated using isolated left atrium isometric force measurements, in vivo electrocardiogram (ECG) recordings, patch clamp technique, and confocal microscopy. It was observed that (-)-terpinen-4-ol reduced contraction force in an isolated left atrium at millimolar concentrations. Conversely, it induced a positive inotropic effect and extrasystoles at micromolar concentrations, suggesting that (-)-terpinen-4-ol may have arrhythmogenic activity on cardiac tissue. In anaesthetized animals, (-)-terpinen-4-ol also elicited rhythm disturbance, such as supraventricular tachycardia and atrioventricular block. To investigate the cellular mechanism underlying the dual effect of (-)-terpinen-4-ol on heart muscle, experiments were performed on isolated ventricular cardiomyocytes to determine the effect of (-)-terpinen-4-ol on L-type Ca²⁺ currents, Ca²⁺ sparks, and Ca²⁺ transients. The arrhythmogenic activity of (-)-terpinen-4-ol in vitro and in vivo may be explained by its effect on intracellular Ca²⁺ handling. Taken together, our data suggest that (-)-terpinen-4-ol has cardiac arrhythmogenic activity.

Anti-obesity effects of hispidin and Alpinia zerumbet bioactives in 3T3-L1 adipocytes

Obesity and its related disorders have become leading metabolic diseases. In the present study, we used 3T3-L1 adipocytes to investigate the anti-obesity activity of hispidin and two related compounds that were isolated from Alpinia zerumbet (alpinia) rhizomes. The results showed that hispidin, dihydro-5,6-dehydrokawain (DDK), and 5,6-dehydrokawain (DK) have promising anti-obesity properties. In particular, all three compounds significantly increased intracellular cyclic adenosine monophosphate (cAMP) concentrations by 81.2% ± 0.06%, 67.0% ± 1.62%, and 56.9% ± 0.19%, respectively. Hispidin also stimulated glycerol release by 276.4% ± 0.8% and inhibited lipid accumulation by 47.8% ± 0.16%. Hispidin and DDK decreased intracellular triglyceride content by 79.5% ± 1.37% and 70.2% ± 1.4%, respectively, and all three compounds inhibited glycerol-3-phosphate dehydrogenase (GPDH) and pancreatic lipase, with hispidin and DDK being the most potent inhibitors. Finally, none of the three compounds reduced 3T3-L1 adipocyte viability. These results highlight the potential for developing hispidin and its derivatives as anti-obesity compounds.

Identification of Volatiles in Leaves of Alpinia zerumbet ‘Variegata’ Using Headspace Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry

Alpinia zerumbet ‘Variegata’ is an aromatic medicinal plant, its foliage producing an intense, unique fragrant odor. This study identified 46 volatile compounds in the leaf tissue of this plant using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The major compounds included 1, 8-cineole (43.5%), p-cymene (14.7%), humulene (5.5%), camphor (5.3%), linalool (4.7%), ( E)-methyl cinnamate (3.8%), γ-cadinene (3.3%), humulene oxide II (2.1%) and α-terpineol (1.5%). The majority of the volatiles were terpenoids of which oxygenated monoterpenes were the most abundant, accounting for 57.2% of the total volatiles. Alcohols made up the largest (52.8%) and aldehydes the smallest (0.2%) portions of the volatiles. Many bioactive compounds were present in the volatiles.

Toxic essential oils. Part II: chemical, toxicological, pharmacological and microbiological profiles of Artemisia annua L. volatiles

Botanical drugs based on Artemisia annua L. (Asteraceae) are important in the treatment of malaria. Alongside with artemisinin, this aromatic species produces high and variable amounts of other chemicals that have mostly unknown biological/pharmacological activities. Herein, we have studied the toxicological/pharmacological profile of volatile constituents of a Serbian population of A. annua. Fifty-eight components were identified, among them, artemisia ketone (35.7%), α-pinene (16.5%) and 1,8-cineole (5.5%) were the most abundant ones. Significant variability of A. annua volatile profile was confirmed by means of agglomerative hierarchical cluster analysis indicating the existence of several different A. annua chemotypes. In an attempt to connect the chemical profile of A. annua oil with its biological/toxicological effects, we have evaluated in vivo and/or in vitro toxicity (including hepato- and nephrotoxicity/protection), antinociceptive, antioxidant (DPPH, ABTS and superoxide radical scavenging activity assays), enzyme inhibiting (protein kinase A and α-amylase) and antimicrobial potential of A. annua oil and of its constituents. Our results revealed that the beneficial properties of A. annua botanical drugs are not limited only to their antimalarial properties. Taking into account its relatively low toxicity, the usage of A. annua volatiles (at least of the herein studied population) does not represent a health risk.

Vasorelaxant and antihypertensive effects of methanolic fraction of the essential oil of Alpinia zerumbet

Alpinia zerumbet is used in folk medicine in Brazil to treat hypertension. However, several pathways involved in the mechanism of vasorelaxation are still unclear. This study was designed to verify the antihypertensive effect of the methanolic fraction of the essential oil of A. zerumbet (MFEOAz) and to characterize its mechanism of action. The thoracic aortic rings from the Wistar rats were perfused in the organ chambers filled with Kreb's solution, where the tension of each ring was measured. The antihypertensive effect of MFEOAz was assessed in rats submitted to chronic hypertension by inhibition of nitric oxide synthesis by indirect measurement of blood pressure with indirect tail cuff method. MFEOAz relaxed phenylephrine and KCl-induced contraction of either endothelium-intact or endothelium-denuded rat aortic rings in a concentration-dependent manner. Pre-incubation with MFEOAz (100 and 300 μg/mL) in Ca(2+)-free Krebs solution attenuated phenylephrine- or caffeine-induced contraction. Pre-incubation with L-NAME, ODQ, wortmannin, atropine, indomethacin, catalase, SOD, TEA, 4-aminopyridine, glibenclamide, apamin, charybdotoxin, or iberiotoxin did not affect MFEOAz-induced relaxation. The intragastric administration of MFEOAz induced an antihypertensive effect. MFEOAz it seems inhibited the calcium influx via voltage-operated calcium channels and receptor-operated calcium channels, as well as inhibition of calcium mobilization from intracellular stores.