Lemon grass (Cymbopogon citratus (D.C) Stapf) polyphenols protect human umbilical vein endothelial cell (HUVECs) from oxidative damage induced by high glucose, hydrogen peroxide and oxidised low-density lipoprotein

Vasorelaxant effect of phenylpropanoids: Methyl eugenol and eugenol in human umbilical cord vein

Methyl-eugenol (ME) and eugenol (EUG) are phenylpropanoids with vasodilatory effects. While EUG's vasorelaxant effect in human umbilical artery (HUA) is known, their action in veins is unclear. This study aimed to evaluate ME and EUG in human umbilical vein (HUV). Isolated HUV underwent tension recordings. ME and EUG caused 100 % relaxation in HUV, with EC50 values corresponding to: 174.3 ± 7.3 and 217.3 ± 6.2 µM for ME and EUG respectively in presence of K+; 362.3 ± 5.4 and 227.7 ± 4.9 µM for ME and EUG respectively and in presence of serotonin (5-HT). It was observed that in presence of BaCl2 and CaCl2 evoked contractions, ME (800 and 1000 µM) and EUG (1000 and 1400 µM) prevent the contractions. In presence of K+ channel blockers it was observed that ME promoted relaxation compared to its control, except in presence of 4-AP, suggesting a possible Ca2+-dependent K+ channel activation for this molecule; EUG increased all EC50 in presence of the K+ blockers except in presence of TEA 1 mM. Greater pharmacological potency was observed for ME. This study highlights natural substances' effects on HUV contractile parameters, suggesting ME and EUG as potential vasodilators in maintaining fetal oxygenation and venous flow during gestational hypertensive syndromes.

Ethnopharmacology, chemical composition and functions of Cymbopogon citratus

Cymbopogon citratus in the gramineous family, also known as lemongrass (LG), is a perennial herb. LG, a drug and food homologous medicine, has a widely recorded medicinal value and food applications. To date, 158 LG compounds have been reported, including terpenoids, flavonoids, phenolic acids. Pharmacological and clinical studies have indicated that LG has antibacterial, neuroprotective, hypoglycemic, hypotensive, anti-inflammatory, and anti-tumor effects. This article reviews LG in ethnopharmacology, chemical composition, pharmacology, food, medicine, and daily chemical applications to provide a basis for the subsequent development of food and medicine.

Plant-derived and dietary phenolic cinnamic acid derivatives: Anti-inflammatory properties

Cinnamic acids are aromatic acids primarily found in plants and plant-derived food. Phenolic cinnamic acids, with one or more hydroxyl groups in the aromatic ring, often contribute to the biological activities attributed to these compounds. The presence of hydroxyl groups and a carboxyl group makes cinnamic acids very hydrophilic, preventing them from crossing biological membranes and exerting their biological activities. To alleviate this condition, a panel of synthetic modifications have been made leading to a diverse set of phenolic cinnamic structures. In this review, an overview of the natural phenolic cinnamic acid derivatives and their plant sources (more than 200) is described. The synthetic approaches to obtain the referred derivatives (more than 200) namely esters and amides are reviewed. Further, their anti-inflammatory activity (more than 70 compounds) is scrutinized. Finally, future directions will be indicated to translate the research on phenolic cinnamic derivatives into potentially effective anti-inflammatory drugs.

Cymbopogon citratus and Citral Overcome Doxorubicin Resistance in Cancer Cells via Modulating the Drug's Metabolism, Toxicity, and Multidrug Transporters

Multidrug resistance (MDR) is the major complex mechanism that causes the failure of chemotherapy, especially with drugs of natural origin such as doxorubicin (DOX). Intracellular drug accumulation and detoxification are also involved in cancer resistance by reducing the susceptibility of cancer cells to death. This research aims to identify the volatile composition of Cymbopogon citratus (lemon grass; LG) essential oil and compare the ability of LG and its major compound, citral, to modulate MDR in resistant cell lines. The composition of LG essential oil was identified using gas chromatography mass spectrometry (GC-MS). In addition, a comparison of the modulatory effects of LG and citral, performed on breast (MCF-7/ADR), hepatic (HepG-2/ADR), and ovarian (SKOV-3/ADR) MDR cell lines, were compared to their parent sensitive cells using the MTT assay, ABC transporter function assays, and RT-PCR. Oxygenated monoterpenes (53.69%), sesquiterpene hydrocarbons (19.19%), and oxygenated sesquiterpenes (13.79%) made up the yield of LG essential oil. α-citral (18.50%), β-citral (10.15%), geranyl acetate (9.65%), ylangene (5.70), δ-elemene (5.38%), and eugenol (4.77) represent the major constituents of LG oil. LG and citral (20 μg/mL) synergistically increased DOX cytotoxicity and lowered DOX dosage by >3-fold and >1.5-fold, respectively. These combinations showed synergism in the isobologram and CI < 1. DOX accumulation or reversal experiment confirmed that LG and citral modulated the efflux pump function. Both substances significantly increased DOX accumulation in resistant cells compared to untreated cells and verapamil (the positive control). RT-PCR confirmed that LG and citral targeted metabolic molecules in resistant cells and significantly downregulated PXR, CYP3A4, GST, MDR1, MRP1, and PCRP genes. Our results suggest a novel dietary and therapeutic strategy combining LG and citral with DOX to overcome multidrug resistance in cancer cells. However, these results should be confirmed by additional animal experiments before being used in human clinical trials.

Albiflorin attenuates high glucose-induced endothelial apoptosis via suppressing PARP1/NF-κB signaling pathway

OBJECTIVE

Paeonia lactiflora Pall has long been recognized as an anti-inflammatory traditional Chinese herbal medicine. We aimed to study the pharmacological action of albiflorin, an active ingredient extracted from the roots of Paeonia lactiflora Pall, on diabetic vascular complications.

METHODS

Human umbilical vein endothelial cells (HUVECs) were stimulated with high glucose and treated with 5, 10, and 20 μM albiflorin. CCK-8 assay, EdU staining, Annexin V-FITC staining, transwell assay, scratch test, RT-PCR, ELISA, Western blot, and immunofluorescence were carried out. SwissTargetPrediction database was used for screening targets of albiflorin and molecular docking was done using Autodock Vina software.

RESULTS

Albiflorin treatment dose-dependently alleviated high glucose-induced viability loss of HUVECs. In addition, albiflorin promoted the proliferation and migration, while inhibited apoptosis and the release of TNF-α, IL-6, and IL-1β in HUVECs. PARP1 was predicted and confirmed to be a target for albiflorin in vitro. Albiflorin targeted PARP1 to inhibit the activation of NF-κB. Transfection of HUVECs with PARP1 overexpression plasmids effectively reversed the effects of albiflorin on high glucose-treated HUVECs.

CONCLUSIONS

Albiflorin suppressed high glucose-induced endothelial cell apoptosis and inflammation, suggesting its potential in treating diabetic vascular complications. The action of albiflorin possibly caused by its regulation on inhibiting PARP1/NF-κB signaling.

Pharmacological screening of species from the Lippia genus, content in terpenes and phenylpropanoids, and their vasorelaxing effects on human umbilical artery

BACKGROUND

Naturally occurring bioactive compounds have a plethora of biological effects.

OBJECTIVE

In this study, we examined a pharmacological screening of natural products on the human umbilical artery (HUA).

METHODS

HUA preparations were used to follow contractions by KCl (60 mM) and tested at different concentrations (1-5000 μg/mL and μM) of the Lippia alba (EOLa) and Lippia origanoides (EOLo) essential oils, terpenes (citral, limonene perilic alcohol) and phenylpropanoids (eugenol, methyl eugenol). Discussion/Results: The reduction corresponded to approximately 100%, except for limonene (80±1.2 %). When evaluating the concentration of the natural product that promotes 50 % relaxation of the HUA contracted by KCL, EC50 values were: 424.3 μg/mL (EOLa); 468.7±6.7 μg/mL (EOLo); 264.2 ± 8.2 μM (citral); 677.8±5.4 μM (limonene); 186.3±6.4 μM (peryl alcohol); 986.4±7.9 μM (eugenol); and 279.1±4.4 μM (methyl-eugenol). Perillyl alcohol had a lower EC50 (consequently it has a higher pharmacological potency).

CONCLUSION

The plant extracts have a promising vasorelaxing effect in HUAs, paving the way for future investigations: as applications in diseases related to these vessels, such as preeclampsia.

Camel Grass Phenolic Compounds: Targeting Inflammation and Neurologically Related Conditions

BACKGROUND

The use of plants for therapeutic purposes has been supported by growing scientific evidence.

METHODS

This work consisted of (i) characterizing the phenolic compounds present in both aqueous and hydroethanol (1:1, v/v) extracts of camel grass, by hyphenated liquid chromatographic techniques, (ii) evaluating their anti-inflammatory, antioxidant, and neuromodulation potential, through in vitro cell and cell-free models, and (iii) establishing a relationship between the chemical profiles of the extracts and their biological activities.

RESULTS

Several caffeic acid and flavonoid derivatives were determined in both extracts. The extracts displayed scavenging capacity against the physiologically relevant nitric oxide (^•NO) and superoxide anion (O₂^•-) radicals, significantly reduced NO production in lipopolysaccharide (LPS)-stimulated macrophages (RAW 264.7), and inhibited the activity of hyaluronidase (HAase), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Some of these bioactivities were found to be related with the chemical profile of the extracts, namely with 3-caffeoylquinic, 4-caffeoylquinic, chlorogenic, and p-coumaric acids, as well as with luteolin and apigenin derivatives.

CONCLUSIONS

This study reports, for the first time, the potential medicinal properties of aqueous and hydroethanol extracts of camel grass in the RAW 264.7 cell model of inflammation, and in neurologically related conditions.

Effect of Lippia alba (Mill.) N.E. Brown Essential Oil on the Human Umbilical Artery

Lippia alba is popularly known as lemon balm, with its essential oil (EO) cited for displaying antimicrobial, sedative, and vasorelaxant effects. Yet, its action on isolated human vessels has not been described in the literature. Thus, we evaluated the vasorelaxant effect of essential oil of L. alba (EOLa) on human umbilical arteries (HUA) isolated in organ baths. HUA rings were isolated, subjected to contractions induced by potassium chloride (KCl), serotonin (5-HT), or histamine (HIST) to record the isometric tension, and then treated with EOLa (30-1000 µg/mL). The EOLa showed a more prominent inhibitory effect on the pharmacomechanical coupling contraction via HIST with an EC₅₀ value of 277.1 ± 8.5 µg/mL and maximum relaxant effect at 600 µg/mL. The addition of tetraethylammonium (TEA) or 4-aminopyridine (4-AP) in HUA preparations did not inhibit EOLa total relaxant effect at 1000 µg/mL. In the presence of gliblenclamide (GLI), the oil relaxed the HUA rings by 90.8% at maximum concentration. The EOLa was also investigated for its effects on voltage-operated calcium channels (VOCCs), where the HUA preincubation with this oil at 1000 μg/mL inhibited BaCl₂ (0.1-30 mM)-induced contractions. This study demonstrates for the first time that EOla has a vasorelaxant effect on HUA and its particular blockade of VOCCs.

Exploring the Anti-Hypertensive Potential of Lemongrass—A Comprehensive Review

Simple Summary

Lemongrass is an herb used in folk medicine for the treatment of hypertension, although its pharmacological potential has not yet been thoroughly studied. This paper provides the first comprehensive review on the anti-hypertensive potential of lemongrass, from in vitro to clinical studies. Even though the composition of lemongrass is dependent on its geographical origin, citral constitutes its major compound. Both citral and lemongrass display vasorelaxant activity ex vivo, promoting the secretion of endothelial vasodilators and the blockage of calcium channels in the vascular smooth muscle. Additionally, citral also displays a negative chronotrope effect. In animal models and in human subjects, lemongrass significantly decreases blood pressure, probably due to the combination of the above-mentioned effects together with diuretic activity. Future preclinical studies are necessary to identify other anti-hypertensive compounds/pathways, as well as to better characterize the safety profile of lemongrass.

Abstract

Lemongrass (Cymbopogon citratus (DC) Stapf) is a herb commonly used in folk medicine for many purposes. However, its anti-hypertensive potential has not yet been thoroughly studied. This paper reviews the anti-hypertensive effects of both lemongrass and its main compound citral in in vitro, ex vivo, preclinical and clinical studies. Lemongrass essential oil contains terpenes and their derivatives, whereas extracts contain different classes of polyphenols. Both citral and lemongrass display vasorelaxant activity ex vivo, acting by the promotion of endothelial nitric oxide/prostanoids secretion together with the blockage of calcium channels in the vascular smooth muscle. Citral also displays a negative chronotrope effect, probably due to a centrally mediated enhancement of parasympathetic activity. In both healthy and hypertensive animals, the acute administration of lemongrass results in a decrease in blood pressure, sometimes accompanied by a compensatory increase in heart rate. Similarly, in healthy and hypertensive human subjects, the consumption of lemongrass tea decreases blood pressure. Additionally, a weak/moderate diuretic activity has also been reported in animals and humans, although the mechanisms of action remain elusive. Future preclinical studies are necessary to identify other compounds with anti-hypertensive activity and additional pharmacological pathways. Although well tolerated, the safety profile of lemongrass should be better characterized.

Loxin Reduced the Inflammatory Response in the Liver and the Aortic Fatty Streak Formation in Mice Fed with a High-Fat Diet

Oxidized low-density lipoprotein (ox-LDL) is the most harmful form of cholesterol associated with vascular atherosclerosis and hepatic injury, mainly due to inflammatory cell infiltration and subsequent severe tissue injury. Lox-1 is the central ox-LDL receptor expressed in endothelial and immune cells, its activation regulating inflammatory cytokines and chemotactic factor secretion. Recently, a Lox-1 truncated protein isoform lacking the ox-LDL binding domain named LOXIN has been described. We have previously shown that LOXIN overexpression blocked Lox-1-mediated ox-LDL internalization in human endothelial progenitor cells in vitro. However, the functional role of LOXIN in targeting inflammation or tissue injury in vivo remains unknown. In this study, we investigate whether LOXIN modulated the expression of Lox-1 and reduced the inflammatory response in a high-fat-diet mice model. Results indicate that human LOXIN blocks Lox-1 mediated uptake of ox-LDL in H4-II-E-C3 cells. Furthermore, in vivo experiments showed that overexpression of LOXIN reduced both fatty streak lesions in the aorta and inflammation and fibrosis in the liver. These findings were associated with the down-regulation of Lox-1 in endothelial cells. Then, LOXIN prevents hepatic and aortic tissue damage in vivo associated with reduced Lox-1 expression in endothelial cells. We encourage future research to understand better the underlying molecular mechanisms and potential therapeutic use of LOXIN.

NMR Metabolome-Based Classification of Cymbopogon Species: a Prospect for Phyto-equivalency of its Different Accessions Using Chemometric Tools

Cymbopogon species are widely distributed worldwide and known for their high essential oil content with potential commercial and medicinal benefits justifying for their inclusion in food and cosmetics. Most species received scant characterization regarding their full complement of bioactive constituents necessary to explain their medicinal activities. In this study, the metabolite profiles of 5 Cymbopogon species, C. citratus, C. flexuosus, C. procerus, C. martini, and C. nardus, were characterized via NMR-based metabolomics. The results of 13 shoot accessions revealed the identification and quantification of 23 primary and secondary metabolites belonging to various compound classes. Multivariate analyses were used for species classification, though found not successful in discrimination based on geographical origin. Nevertheless, C. citratus was found particularly enriched in neral, geranial, (E)-aconitic acid, isoorientin, and caffeic acid as the major characterizing metabolites compared to other species, while an unknown apigenin derivative appeared to discriminate C. martini. The high essential oil and phenolic content in C. citratus emphasizes its strong antioxidant activity, whereas (E)-aconitic acid accounts for its traditional use as insecticide. This study affords the first insight into metabolite compositional differences among Cymbopogon species. Moreover, antimicrobial, insecticidal, antidiabetic, and antioxidant compounds were identified that can be utilized as biomarkers for species authentication.

The use of medicinal plants by Paraguayan migrants in the Atlantic Forest of Misiones, Argentina, is based on Guaraní tradition, colonial and current plant knowledge

ETHNOPHARMACOLOGICAL RELEVANCE

Information on the use of medicinal plants in the daily life by Paraguayan people is scarce in mainstream scientific literature. The study on the Paraguayan diaspora in the Provincia de Misiones, Argentina, gives an insight into Guaraní traditions, colonial legacy and current search for new medicinal plants to address new health challenges.

AIM OF THE STUDY

To document the use of medicinal plants by Paraguayan mestizo migrants who moved into a new country, yet within the same ecological region. The present and past uses of medicinal plants were compared to understand the continuity and change in the Paraguayan herbal pharmacopoeia.

MATERIALS AND METHODS

Fieldwork based on ethnographic and ethnobotanical techniques was carried out in the Provincia de Misiones, Argentina, in 2014, 2015, and 2019. Eighty-five Paraguayan migrants and their descendants from eastern Paraguay took part in the study. The list of recorded plants was compared with the information in historical sources from Paraguay, to examine the continuity and changes in Paraguayan herbal medicine, and with the present-day ethnobotanical studies from Paraguay. Ethnopharmacological and phytochemical studies on the medicinal plants with the highest consensus of uses were reviewed.

RESULTS

Altogether, 204 medicinal plant species were recorded. The most frequently mentioned species represented a combination of plants native to the New and Old World. Nearly 40% of the present-day Paraguayan pharmacopoeia shows continuity from colonial and post-colonial periods. Plants were used for 19 medical categories, of which digestive, circulatory and those belonging to humoral medicine were the most prevalent. The ongoing search of plants to treat new health problems is illustrated by reports of 40 species used for hypertension, 26 for diabetes and 18 to lower cholesterol. There is still little evidence for the effectiveness of these plants in the pharmacological literature. Paraguayan migrants were able to continue their traditional plant medicine in Misiones, Argentina, in a substantial way.

CONCLUSION

This study was carried out in a geographic area with a long-standing tradition of Guaraní medicine. Paraguayan migrants in Misiones integrate pre-Hispanic Guaraní names and uses of plants and old humoral concepts with current adaptation of plants to meet new health challenges. Several of the uses described in early colonial times are still practiced, giving a solid background for in-depth studies of the local pharmacopoeia.

Effects of citral on serum antioxidant status and liver genes expressions of paraoxonase 1 and nitric oxide synthase in a rat model of streptozotocin-induced diabetes mellitus

Background:

Citral (C₁₀H₁₆O) is the main ingredient of Cymbopogon citratus (lemongrass oil) and can reduce the side effects of oxidative stress. Diabetes caused by insulin deficiency induces oxidative stress in the liver.

Aims:

This study aimed to investigate the ameliorative effects of citral on selected oxidative parameters and the gene expression of paraoxonase 1 (PON1) and endothelial nitric oxide synthase (eNOS) in a rat model of streptozotocin (STZ)-induced diabetes mellitus.

Methods:

Forty rats were divided into four groups at random: control (C), control citral (CC), and two STZ-induced diabetic groups (diabetic (D) and citral diabetic (CD)). After diabetes confirmation (day 7), gavage treatment with citral (300 mg/kg body weight (BW)) was started in the CD and CC groups and continued for two weeks.

Results:

On day 21 of the study, following treatment with citral for 14 days, the serum levels of total antioxidant capacity (TAC), and PON1 in the CD group were significantly increased compared to those in the D group (P<0.05). While treatment with citral caused a significant decrease in the Malondialdehyde (MDA), and eNOS in the CD group compared to those of the D group (P<0.001). The expression rate of liver PON1 gene was considerably upregulated in the CD group compared to that in the D group (P<0.001); while the opposite was observed for eNOS gene expression. However, there was no significant difference between the CC and C groups in terms of all examined parameters (P>0.05).

Conclusion:

This study showed positive effects of citral on serum antioxidant status and liver gene expression of PON1 and eNOS in diabetic rats.

Leonurine Ameliorates Oxidative Stress and Insufficient Angiogenesis by Regulating the PI3K/Akt-eNOS Signaling Pathway in H2O2-Induced HUVECs

Thrombus is considered to be the pathological source of morbidity and mortality of cardiovascular disease and thrombotic complications, while oxidative stress is regarded as an important factor in vascular endothelial injury and thrombus formation. Therefore, antioxidative stress and maintaining the normal function of vascular endothelial cells are greatly significant in regulating vascular tension and maintaining a nonthrombotic environment. Leonurine (LEO) is a unique alkaloid isolated from Leonurus japonicus Houtt (a traditional Chinese medicine (TCM)), which has shown a good effect on promoting blood circulation and removing blood stasis. In this study, we explored the protective effect and action mechanism of LEO on human umbilical vein endothelial cells (HUVECs) after damage by hydrogen peroxide (H₂O₂). The protective effects of LEO on H₂O₂-induced HUVECs were determined by measuring the cell viability, cell migration, tube formation, and oxidative biomarkers. The underlying mechanism of antioxidation of LEO was investigated by RT-qPCR and western blotting. Our results showed that LEO treatment promoted cell viability; remarkably downregulated the intracellular generation of reactive oxygen species (ROS), malondialdehyde (MDA) production, and lactate dehydrogenase (LDH); and upregulated the nitric oxide (NO) and superoxide dismutase (SOD) activity in H₂O₂-induced HUVECs. At the same time, LEO treatment significantly promoted the phosphorylation level of angiogenic protein PI3K, Akt, and eNOS and the expression level of survival factor Bcl2 and decreased the expression level of death factor Bax and caspase3. In conclusion, our findings suggested that LEO can ameliorate the oxidative stress damage and insufficient angiogenesis of HUVECs induced by H₂O₂ through activating the PI3K/Akt-eNOS signaling pathway.

Formulation Effects in the Antioxidant Activity of Extract from the Leaves of Cymbopogon citratus (DC) Stapf

Cymbopogon citratus DC (Stapf.) is a perennial grass and it is distributed around the world. It is used as a condiment for food and beverage flavouring in the form of infusions and decoctions of its dried leaves. Our previous studies have shown antioxidant, anti-inflammatory and gastroprotective activities for the infusion and its phenolic fractions. The aim of the present work was to develop oral dosage forms from a Cymbopogon citratus extract to be used as a functional food with antioxidant properties. Initially, an essential oil-free infusion was prepared, lyophilized and characterized by HPLC-PDA. Total phenols were quantified with the Folin-Ciocalteu method and the antioxidant activity was assessed by DPPH assay. Gelatine capsules containing the extract with different excipients, selected after DSC and IR trials, were prepared. A formulation exhibiting better antioxidant behaviour in a gastric environment was attained. These results suggest that the proposed formulation for this extract could be a valuable antioxidant product and, consequently, make an important contribution to "preventing" and minimizing diseases related to oxidative stress conditions.

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.

Potential Effect of Polyphenolic-Rich Fractions of Corn Silk on Protecting Endothelial Cells against High Glucose Damage Using In Vitro and In Vivo Approaches

Endothelial cell dysfunction is considered to be one of the major causes of vascular complications in diabetes. Polyphenols are known as potent antioxidants that can contribute to the prevention of diabetes. Corn silk has been reported to contain polyphenols and has been used in folk medicine in China for the treatment of diabetes. The present study aims to investigate the potential protective role of the phenolic-rich fraction of corn silk (PRF) against injuries to vascular endothelial cells under high glucose conditions in vitro and in vivo. The protective effect of PRF from high glucose toxicity was investigated using human umbilical vein endothelial cells (HUVECs). The protective effect of PRF was subsequently evaluated by using in vivo methods in streptozotocin (STZ)-induced diabetic rats. Results showed that the PRF significantly reduced the cytotoxicity of glucose by restoring cell viability in a dose-dependent manner. PRF was also able to prevent the histological changes in the aorta of STZ-induced diabetic rats. Results suggested that PRF might have a beneficial effect on diabetic patients and may help to prevent the development and progression of diabetic complications such as diabetic nephropathy and atherosclerosis.

Chemical Properties and Therapeutic Potential of Citral, a Monoterpene Isolated from Lemongrass

BACKGROUND

Citral is one of the main components of lemongrass oil present at a concentration of 65-85% approximately and is generally separated by steam refining. It is an important component in the manufacturing of scents, citrus chemicals, cosmetics, food and pharmaceutical products.

OBJECTIVES

This article aims at reviewing the published literature to highlight the metabolism, extraction strategies and therapeutic significance of citral for improving the scope of its application in the food and pharma industry.

DISCUSSIONS

Apart from steam refining, there are other techniques like solvent extraction, supercritical fluid extraction and ultrasonication by which citral can be extracted and the method of extraction defines its quality. It is an unstable molecule and undergoes rapid deterioration on exposure to air. Citral is biosynthesized by the plants through the 5 carbon precursor isopentenyl diphosphate (IPP) units utilizing two diverse biochemical pathways, acetate- mevalonate (acetate- MVA) pathway or 2C-methylerythritol-4-phosphate (MEP). Orally Citral was absolutely digested in the gastrointestinal tract and its metabolism leads to the discharge of metabolites which include a number of acids and a biliary glucuronide. There is no scientific evidence about the long term bioavailability of citral in the body and it has no adverse effect on tissue related to its accumulation and delayed excretion. Citral exhibits various important therapeutic properties like antimicrobial, antioxidant, anticancer, anti-diabetic and anti-inflammatory.

CONCLUSION

Citral is a potent biomolecule with various important biological activities and therapeutic implications. Strategies are required to increase the stability of citral which could increase its applications.

Phenolic Composition and Antioxidant Activity of Plants Belonging to the Cephalaria (Caprifoliaceae) Genus

The genus Cephalaria, belonging to the Caprifoliaceae family, is a rich source of interesting secondary metabolites, including mainly saponins which display a variety of biological activities, such as immunomodulatory, antimicrobial and hemolytic effects. Besides these compounds, flavonoids and phenolic acids were identified in Cephalaria species. Cephalaria is employed in traditional medicine e.g., to cure cardiac and lung diseases, rheumatism, and regulate menstruation. In this review we focus on the phenolic compound composition and antioxidative activity of Cephalaria species. The antioxidant effect can be explained by flavonoids present in all parts of these plants. However, future efforts should concentrate more on in vitro and in vivo studies and also on clinical trials in order to confirm the possibility of using these plants as natural antioxidants for the pharmacology, food or cosmetic industries.

Berberis microphylla G. Forst (Calafate) Berry Extract Reduces Oxidative Stress and Lipid Peroxidation of Human LDL

Calafate (Berberis microphylla G. Forst) is a Patagonian barberry very rich in phenolic compounds. Our aim was to demonstrate, through in vitro models, that a comprehensive characterized calafate extract has a protective role against oxidative processes associated to cardiovascular disease development. Fifty-three phenolic compounds (17 of them not previously reported in calafate), were tentatively identified by Ultra-Liquid Chromatography with Diode Array Detector, coupled to Quadrupole-Time of Fly Mass Spectrometry (UHPLC-DAD-QTOF). Fatty acids profile and metals content were studied for the first time, by Gas Chromatography Mass Spectrometry (GC-MS) and Total X-ray Fluorescence (TXRF), respectively. Linolenic and linoleic acid, and Cu, Zn, and Mn were the main relevant compounds from these groups. The bioactivity of calafate extract associated to the cardiovascular protection was evaluated using Human Umbilical Vein Endothelial Cells (HUVECs) and human low density lipoproteins (LDL) to measure oxidative stress and lipid peroxidation. The results showed that calafate extract reduced intracellular Reactive Oxygen Species (ROS) production (51%) and completely inhibited LDL oxidation and malondialdehyde (MDA) formation. These findings demonstrated the potential of the relevant mix of compounds found in calafate extract on lipoperoxidation and suggest a promising protective effect for reducing the incidence of cardiovascular disease.

Improvement of endothelial function by Gunnera tinctoria extract with antioxidant properties

BACKGROUND

Gunnera tinctoria has been collected by Mapuche-Pewenche people for food and medicinal purposes. The high polyphenol content of methanolic extract from G. tinctoria leaves with chemical constituents such as ellagic acid and quercetin derivatives suggests its application to prevent endothelial dysfunction and oxidative stress. The aim of this study was to provide evidence of the protective effect of this extract on endothelial function by reducing oxidative stress induced by high D-glucose and H₂O₂, as well as by stimulating nitric oxide (NO) levels in human umbilical vein endothelial cells (HUVECs).

RESULTS

A methanolic extract with a high content of polyphenols (520 ± 30 mg gallic acid equivalents/g dry extract) was obtained from G. tinctoria leaves. Its main constituent was ellagic acid. The results of Ferric reducing antioxidant power and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays of the extract confirmed its antioxidant activity by inhibition pathway of radical species. The incubation of HUVECs with the extract decreased the apoptosis and reactive oxygen species (ROS) synthesis induced by high extracellular concentration of D-glucose or hydrogen peroxide. The extract increased endothelial NO levels and reduced vasoconstriction in human placental vessels.

CONCLUSIONS

This study provides evidence about the antioxidant and endothelial protective properties of methanolic G. tinctoria leaf extract. The extract improves the availability of NO in HUVECs, inhibiting the production of ROS and vasoconstriction.

Role of Polyphenols and Carotenoids in Endothelial Dysfunction: An Overview from Classic to Innovative Biomarkers

Nowadays, the dramatically increased prevalence of metabolic diseases, such as obesity and diabetes mellitus and their related complications, including endothelial dysfunction and cardiovascular disease, represents one of the leading causes of death worldwide. Dietary nutrients together with healthy lifestyles have a crucial role in the endothelium health-promoting effects. From a growing body of evidence, active natural compounds from food, including polyphenols and carotenoids, have attracted particular attention as a complementary therapy on atherosclerosis and cardiovascular disease, as well as preventive approaches through the attenuation of inflammation and oxidative stress. They mainly act as radical scavengers by promoting a variety of biological mechanisms, such as improvements in endothelial function, blood pressure, platelet activity, and insulin sensitivity, and by modulating various known biomarkers. The present review highlights the role of polyphenols and carotenoids in early endothelial dysfunction with attention to their beneficial effect in modulating both classical and recent technologically generated emerging biomarkers. These, alone or in combination, can play an important role in the prediction, diagnosis, and evolution of cardiovascular disease. However, a main challenge is to speed up early and prompt new interventions in order to prevent or slow down disease progression, even with an adequate intake of bioactive compounds. Hence, there is an urgent need of new more validated, appropriate, and reliable diagnostic and therapeutic biomarkers useful to diagnose endothelial dysfunction at an earlier stage.

Inhibitory potentials of Cymbopogon citratus oil against aluminium-induced behavioral deficits and neuropathology in rats

Cymbopogon citratus is a tropical phytomedicinal plant that is widely known for its hypoglycemic, hypolipidemic, anxiolytic, sedative, antioxidative and anti-inflammatory properties. In this study, we have examined the neuroprotective effects of the essential oil (ESO) of Cymbopogon citratus, following aluminum chloride (AlCl₃)-induced neurotoxicity within the cerebellum of Wistar rats. A total of 40 adult male Wistar rats were assigned into five groups and treated orally as follows: A–phosphate-buffered saline (1 ml daily for 15 days); B–ESO (50 mg/kg daily for 15 days); C–AlCl₃ (100 mg/kg daily for 15 days); D–AlCl₃ then ESO (100 mg/kg AlCl₃ daily for 15 days followed by 50 mg/kg ESO daily for subsequent 15 days); E–ESO then AlCl₃ (50 mg/kg ESO daily for 15 days followed by 100 mg/kg AlCl₃ daily for following 15 days). To address our questions, we observed the locomotion and exploratory behavior of the rats in the open field apparatus and subsequently evaluated cerebellar oxidative redox parameters, neural bioenergetics, acetylcholinesterase levels, transferrin receptor protein, and total protein profiles by biochemical assays. Furthermore, we investigated cerebellar histomorphology and Nissl profile by H&E and Cresyl violet Nissl staining procedures. ESO treatment markedly attenuated deficits in exploratory activities and rearing behavior following AlCl₃ toxicity, indicating its anxiolytic potentials. Additionally, AlCl₃ evokedincrease in malondialdehyde and nitric oxide levels, as well as repressed cerebellar catalase, glutathione peroxidase, and superoxide dismutase profiles were normalised to baseline levels by ESO treatment. Treatment with ESO, ergo, exhibits substantial neuroprotective and modulatory potentials in response to AlCl₃ toxicity.

UPLC-Orbitrap HRMS metabolic profiling of Cymbopogon citratus cultivated in Egypt; neuroprotective effect against AlCl3-induced neurotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (lemongrass) is commonly used in teas, soups and treat inflammatory-based ailments, vascular and nervous disorders.

AIM OF THE STUDY

The study aimed to evaluate the neuroprotective effect of Cymbopogon citratus leaves through scientific protocol. The effect of aqueous (AE) and ethanolic (EE) extracts was evaluated against AlCl₃-induced Alzheimer's disease (AD) in rats. Metabolic profiling of the plant, isolation of bioactive compounds and standardization of the active fraction were investigated.

MATERIALS AND METHODS

AE of Cymbopogon citratus leaves was prepared as per traditional method (infusion), EE was prepared by repeated maceration in 90% ethanol, bioactive fraction (BAEE) was obtained from EE and the active compounds thereof were obtained by column chromatography. Metabolic profiling of Cymbopogon citratus was performed by UPLC-Orbitrap HRMS and HPLC was used for standardization. AlCl₃-induced Alzheimer's rats were used to assess neuroprotective effect of the extracts. Neuroprotective mechanism(s) of Cymbopogon citratus extracts was clarified through histopathological examination of brain tissues, estimation of AD biochemical markers, oxidative stress and neuroinflammation in brain homogenates. In addition, antioxidant (using DPPH assay) and anticholinesterase (using modified Ellman's method) activities were investigated.

RESULTS

AlCl₃-treated rats (17 mg/kg/day) showed histopathological alteration in brain tissues together with elevated levels of Aβ, tau proteins, MDA, NF-kB and IL-6. However, treatment with AE and EE of Cymbopogon citratus leaves prevented the pathological changes and maintained the levels of oxidative stress and inflammatory markers. In addition, BAEE significantly inhibited acetylcholinesterase enzyme (2.11 ± 0.11 mg/ml) and exhibited a strong antioxidant activity (24.99 ± 0.00 μg/ml). UPLC-MS of Cymbopogon citratus leaves showed peaks for twenty-eight compounds, twenty-one of them were identified. Three flavonoids; isoorientin, isoschaftoside and luteolin-7-O-neohesperidoside were isolated from BAEE as major constituents. The powdered leaves of Cymbopogon citratus was found to contain remarkable amounts of caffeic acid (3.49 mg/g dry wt.) and isoorientin (7.37 mg/g dry wt.) as determined by HPLC.

CONCLUSION

Cymbopogon citratus ethanolic extract attenuates AlCl₃-induced neurotoxicity in rats through inhibition of oxidative stress and inflammatory markers. This effect could possibly attributed, in part to its high content of phenolic acids and flavonoids. Accordingly, we recommend Cymbopogon citratus leaves for protection against AD.

Extracts from Cephalaria Uralensis (Murray) Roem. & Schult. and Cephalaria Gigantea (Ledeb.) Bobrov as Potential Agents for Treatment of Acne Vulgaris: Chemical Characterization and In Vitro Biological Evaluation

The aim of this study was to compare the chemical composition, as well as antioxidant, anti-inflammatory, antiacne, and cytotoxic activites of various extracts of Cephalaria gigantea and C. uralensis. It is worth underlining that we are the first to characterize the composition and evaluate the biological properties of extracts from Cephalaria gigantea and C. uralensis. Thus, the LC-DAD-MS3 analysis revealed the presence of 41 natural products in studied extracts. The 5-O-caffeoylquinic acid, isoorinetin, and swertiajaponin were the main detected compounds. Among the tested samples, ethanol extract of the aerial parts of C. uralensis (CUE) possessed the most suitable biological properties. It exhibited moderate ability to scavenge free radicals and good capacity to inhibit cyclooxygenase-1, as well as cyclooxygenase-2. Moreover, CUE possessed moderate antibacterial activity against all tested bacterial strains (S. aureus, S. epidermidis, and P. acnes), and importantly, it was non-toxic towards normal skin fibroblasts. Taking into account the value of calculated therapeutic index (>10), it is worth noting that CUE can be subjected to in vivo study. Thus, CUE constitutes a very promising antiacne agent.

Vascular activity of infusion and fractions of Cymbopogon citratus (DC) Stapf. in human arteries

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (DC.) Stapf has been traditionally used mainly for inflammatory diseases and hypertension. However, the mechanisms underlying its vascular activity remain to be fully characterized and the fractions responsible for its cardiovascular activity are still unknown.

AIM OF THE STUDY

In this study, we aimed to assess the vascular activity of Cymbopogon citratus in human arteries and to study the role of cyclooxygenase in its vasorelaxant effects.

MATERIALS AND METHODS

Vascular effects of leaves infusion and three fractions (phenolic acids, flavonoids and tannins) were studied using distal segments of human internal thoracic arteries harvested from patients undergoing coronary revascularization, which were mounted as rings in tissue organ baths and maintained at 37 °C in Krebs Henseleit buffer. The effect on basal vascular tone, the effect on the noradrenaline-induced contraction and the vasorelaxant effects were assessed. The role of cyclooxygenase was evaluated with indomethacin.

RESULTS

Our results showed a mild effect on the basal vessel tone of the infusion. A significant inhibition on the adrenergic-mediated vasoconstriction was observed for the infusion (0.0002 mg/mL) and the flavonoid fraction (0.2 mg/mL), despite a potentiation was observed in some conditions. A vasorelaxant effect was observed for both the infusion (6.46% of maximal relaxation) and the tannin fraction (26.91% of maximal relaxation, P < 0.05 vs. infusion). Incubation with indomethacin (10 μM) elicited a decrease in the vasorelaxation to the infusion (P < 0.05).

CONCLUSIONS

These results suggest that cyclooxygenase may be involved in the vasorelaxation to the infusion of Cymbopogon citratus and that tannins are the compound fraction mainly responsible for this vasorelaxation.

Combined Extract of Vitis vinifera L. and Centella asiatica Synergistically Attenuates Oxidative Damage Induced by Hydrogen Peroxide in Human Umbilical Vein Endothelial Cells

Endothelial cell injury caused by oxidative stress is a critical factor in the initial stage of vascular diseases. Thus, identification of more effective antioxidants is a promising strategy to protect against endothelial cell injury. Recently, synergistic effects between phytochemicals have received renewed attention for their role in the treatment of various diseases. Vitis vinifera L. and Centella asiatica are well-known medicinal plants with various biological effects. However, the combination of the two has not previously been studied. Here, we investigated the effects of V. vinifera L. leaf and C. asiatica extract combination (VCEC), a standardized herbal blend comprising V. vinifera L. leaf extract (VE) and C. asiatica extract (CE), for its antioxidant activity and for the protection of endothelial cells against hydrogen peroxide (H₂O₂)-mediated oxidative damage in human umbilical vein endothelial cells (HUVECs). VCEC showed higher antioxidant activity than VE or CE in oxygen radical antioxidant capacity assays. In HUVECs, VCEC significantly suppressed increases in the production of intracellular reactive oxygen species, decreased levels of nitric oxide and vascular endothelial-cadherin, and increased endothelial hyperpermeability triggered by H₂O₂. Treatment with VE or CE alone ameliorated HUVEC injury in a pattern similar to VCEC, although their effects were significantly weaker than VCEC. Overall, VCEC exhibited a substantial synergistic effect on protecting endothelial cells against oxidative damage through its antioxidant activity. Therefore, VCEC could be developed as a potential agent for reducing the risk of vascular diseases related to oxidative stress.

Relaxant Effect of Monoterpene (-)-Carveol on Isolated Human Umbilical Cord Arteries and the Involvement of Ion Channels

Carveol is a monoterpene present in the structure of many plant products. It has a variety of biological activities: antioxidant, anticancer and vasorelaxation. However, studies investigating the effect of monoterpenoids on human vessels have not yet been described. Thus, the present study aimed to characterize the effect of (−)-carveol on human umbilical arteries (HUAs). HUA ring preparations were isolated and subjected to isometric tension recordings of umbilical artery smooth muscle contractions. (−)-Carveol exhibited a significant vasorelaxant effect on KCl and 5-HT-induced contractions, obtaining EC₅₀ values of 344.25 ± 8.4 and 175.82 ± 4.05 µM, respectively. The participation of calcium channels in the relaxation produced by (−)-carveol was analyzed using vessels pre-incubated with (−)-carveol (2000 µM) in a calcium-free medium, where the induction of contractions was abolished. The vasorelaxant effect of (−)-carveol on HUAs was reduced by tetraethylammonium (TEA), which increased the (−)-carveol EC₅₀ to 484.87 ± 6.55 µM. The present study revealed that (−)-carveol possesses a vasorelaxant activity in HUAs, which was dependent on the opening of calcium and potassium channels. These results pave the way for further studies involving the use of monoterpenoids for the vasodilatation of HUAs. These molecules have the potential to treat diseases such as pre-eclampsia, which is characterized by resistance in umbilical arteries.

Cymbopogon Proximus Essential Oil Protects Rats against Isoproterenol-Induced Cardiac Hypertrophy and Fibrosis

Cardiac hypertrophy is an independent risk factor of many cardiovascular diseases. Several cardiovascular protective properties of Cymbopogon proximus have been reported. However, no reports investigating the direct effect of C. proximus essential oil on the heart are available. The goal of this study was to explore the cardioprotective effect of C. proximus on cardiac hypertrophy and fibrosis. Male albino rats were administered C. proximus essential oil in the presence or absence of hypertrophic agonist isoproterenol. Cardiac hypertrophy and fibrosis were assessed using real-time polymerase chain reaction (PCR) and histological examination. Pre- treatment of rats with C. proximus decreased the ratio of heart weight to body weight and gene expression of hypertrophy markers atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and β-myosin heavy chain (β-MHC), which were induced by isoproterenol. Moreover, C. proximus prevented the increase in gene expression of fibrosis markers procollagen I and procollagen III and alleviated the collagen volume fraction caused by isoproterenol. The pre- treatment with C. proximus essential oil conferred cardio-protection against isoproterenol- induced cardiac hypertrophy and fibrosis.

Enantiomeric Trimethylallantoin Monomers, Dimers, and Trimethyltriuret: Evidence for an Alternative Catabolic Pathway of Caffeine in Tea Plant

Racemic trimethylallantoin monomer (1), mesomeric and racemic trimethylallantoin dimers (2 and 3), were isolated from tea. Two pairs of optically pure enantiomers (1a, 1b and 3a, 3b) were separated by chiral column from the two racemes (1 and 3). Their structures were elucidated by a combination of extensive spectroscopic techniques, single-crystal X-ray diffraction, and experimental and calculated electronic circular dichroism. A novel caffeine catabolic pathway was proposed based on the caffeine stable isotopic tracer experiments.

Medicinal Herbs Effective Against Atherosclerosis: Classification According to Mechanism of Action

Atherosclerosis is a widespread and chronic progressive arterial disease that has been regarded as one of the major causes of death worldwide. It is caused by the deposition of cholesterol, fats, and other substances in the tunica intima which leads to narrowing of the blood vessels, loss of elasticity, and arterial wall thickening, thus causing difficulty in blood flow. Natural products have been used as one of the most important strategies for the treatment and prevention of cardiovascular diseases for a long time. In recent decades, as interests in natural products including medicinal herbs have increased, many studies regarding natural compounds that are effective against atherosclerosis have been conducted. The purpose of this review is to provide a brief over-view of the natural compounds that have been used for the treatment and prevention of atherosclerosis, and their mechanisms of action based on recent research.

The DPP-4 inhibitor saxagliptin ameliorates ox-LDL-induced endothelial dysfunction by regulating AP-1 and NF-κB

Diabetes-associated cardiovascular complications are the leading cause of death for diabetic patients. Dipeptidyl peptidase 4 (DPP-4) inhibitor agents, known as gliptins, are a class of potent anti-glycemic agents developed to treat diabetes. Recently, gliptins have been shown to have independent cardiovascular benefits. In this study, we revealed the protective role of saxagliptin in vascular endothelial cells. Our data show that saxagliptin suppresses oxidized low-density lipoprotein cholesterol (ox-LDL)-induced expression of its receptor lectin-like ox-LDL receptor-1 (LOX-1). Saxagliptin treatment reduces ox-LDL-induced production of cytokines and vascular adhesion molecules including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), vascular cell adhesion molecule 1 (VCAM-1), and intercellular cell adhesion molecule-1 (ICAM-1). The presence of saxagliptin suppressed ox-LDL-induced adhesion of monocytes to endothelial cells in co-culture adhesion experiments. Moreover, saxagliptin mitigated ox-LDL-induced production of reactive oxygen species and suppressed elevated expression of endothelial nicotinamide adenine dinucleotide phosphate oxidase subunit (NOX-4) induced by ox-LDL. Mechanistically, saxagliptin exerted inhibitory effects against ox-LDL-induced phosphorylation of JNK kinase, expression of the activator protein 1 (AP-1) subunits c-Jun/c-fos, and AP-1 promoter activity. Saxagliptin also suppressed nuclear factor κB (NF-κB) p65 accumulation and inhibited its promoter activity. Our data elaborate the molecular mechanism of saxagliptin-mediated endothelial protection and indicate that saxagliptin could have vascular benefits independent on its anti-glycemic function.

Protective Effect of Pitao (Pitavia punctata (R. & P.) Molina) Polyphenols against the Red Blood Cells Lipoperoxidation and the In Vitro LDL Oxidation

The oxidative stress is characterized by an imbalance between the oxidizing agents and antioxidants; meanwhile, the consumption of antioxidants has been considered as an important tool in the prevention of oxidative stress and its consequences. Pitavia punctata (R. & P.) Molina is an endemic arboreal species from the Chilean Coast Range, in which a large amount of flavonoids has been described. This work focused on characterizing and evaluating, in human erythrocytes, the antioxidant capacity and membrane protection of P. punctata extracts and the in vitro protection of the oxidation of the Low Density Lipoprotein (LDL). The phytochemical screening revealed the presence of Quercetin derivatives and flavonoids, such as (-)-Epicatechin, Kaempferol, and derivatives. The methanolic extract presented an important antioxidant activity, protecting the membrane integrity of the red blood cells against the oxidative damage caused by Hypochlorous acid and inhibiting the oxidation of the LDL lipoprotein.

Flavoalkaloids with a Pyrrolidinone Ring from Chinese Ancient Cultivated Tea Xi-Gui

Chinese Xi-Gui tea is one ancient cultivated variety of Camellia sinensis var. assamica. At present, it is used for producing expensive and elite tea in China. Five new flavoalkaloids, (-)-6-(5''' S)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (ester-type catechins pyrrolidinone E, etc-pyrrolidinone E, 1), (-)-6-(5''' R)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone F, 2) (-)-8-(5''' S)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone G, 3a), (-)-8-(5''' S)- N-ethyl-2-pyrrolidinone-catechin-3- O-gallate (etc-pyrrolidinone I, 4a), (-)-8-(5''' R)- N-ethyl-2-pyrrolidinone-catechin-3- O-gallate (etc-pyrrolidinone J, 4b), and one new naturally occurring natural product (-)-8-(5''' R)- N-ethyl-2-pyrrolidinone-epicatechin-3- O-gallate (etc-pyrrolidinone H, 3b) together with the known flavoalkaloids etc-pyrrolidinones A-D (5, 6, 7a, and 7b) were detected and isolated from Xi-Gui green tea. Their structures were identified by comprehensive NMR spectroscopic analyses. Absolute configurations of 1-3 were established by comparison of the CD analyses with epicatechin-3- O-gallate (ECG). Compounds 1-4 were evaluated for their protection against high glucose induced cell senescence on human umbilical vein endothelia cells (HUVECs) and showed significant protection effects ( p < 0.01) at both 1.0 and 10 μM. A discussion on the possible evolution of tea plants divergent from related food plants on the basis of phytochemical view is also provided.

Mechanistic Study of the In Vitro and In Vivo Inhibitory Effects of Protocatechuic Acid and Syringic Acid on VEGF-Induced Angiogenesis

The antiangiogenic activities of two structurally similar phenolics, protocatechuic acid (PA) and syringic acid (SA), were investigated. In vitro study using HUVECs demonstrated that both PA and SA (at 25 μM) significantly ( p < 0.05) inhibited VEGF-induced cell proliferation by 22.68 ± 5.6% and 21.93 ± 2.0%, respectively; cell migration by 50.04 ± 3.3% and 39.72 ± 4.7%, respectively; cell invasion by 44.16 ± 4.23% and 51.90 ± 2.73%, respectively; and cellular ROS generation by 11.48 ± 6.32% and 21.17 ± 9.10%, respectively. Our mechanistic study revealed that PA and SA blocked the VEGFR2-dependent Akt/ MMP2 and ERK pathways in HUVECs. These inhibitory effects were further confirmed by a decrease of endogenous alkaline phosphatase activity for PA and SA (21.47 ± 1.77% and 10.37 ± 1.27%, respectively) and the suppression of subintestinal vessel plexus formation in Tg (fli1a:EGFP) y1-type transgenic zebrafish embryos. PA and SA down-regulated the angiogenesis-related signal transduction pathway of VEGFα-VEGFR2 or Ang2- Tie2 in zebrafish. Moreover, it was also found that PA demonstrated a better inhibition on VEGF-induced migration of HUVEC and zebrafish vasculature. This might be due to the different number of hydroxyl and methoxy substituents possessed by PA and SA. Taken together, these findings indicate that phenolics PA and SA have potent antiangiogenic activities and are potential targets for the design and development of anticancer agents.

Nutrients and Oxidative Stress: Friend or Foe?

There are different types of nutritionally mediated oxidative stress sources that trigger inflammation. Much information indicates that high intakes of macronutrients can promote oxidative stress and subsequently contribute to inflammation via nuclear factor-kappa B- (NF-κB-) mediated cell signaling pathways. Dietary carbohydrates, animal-based proteins, and fats are important to highlight here because they may contribute to the long-term consequences of nutritionally mediated inflammation. Oxidative stress is a central player of metabolic ailments associated with high-carbohydrate and animal-based protein diets and excessive fat consumption. Obesity has become an epidemic and represents the major risk factor for several chronic diseases, including diabetes, cardiovascular disease (CVD), and cancer. However, the molecular mechanisms of nutritionally mediated oxidative stress are complex and poorly understood. Therefore, this review aimed to explore how dietary choices exacerbate or dampen the oxidative stress and inflammation. We also discussed the implications of oxidative stress in the adipocyte and glucose metabolism and obesity-associated noncommunicable diseases (NCDs). Taken together, a better understanding of the role of oxidative stress in obesity and the development of obesity-related NCDs would provide a useful approach. This is because oxidative stress can be mediated by both extrinsic and intrinsic factors, hence providing a plausible means for the prevention of metabolic disorders.

Isolariciresinol-9'-O-α-L-arabinofuranoside protects against hydrogen peroxide‑induced apoptosis of human umbilical vein endothelial cells via a PI3K/Akt/Bad‑dependent pathway

Isolariciresinol-9'-O-α-L-arabinofuranoside (MWS‑19) isolated from Pinus massoniana Lamb. Fresh pine needles is the major ingredient of the Songling Xuemaikang capsule therapy used for hypertension. The present study aimed to investigate the effects and underlying mechanisms of MWS‑19 on hydrogen peroxide (H2O2)‑induced apoptosis in human umbilical vein endothelial cells (HUVECs). To investigate the effect of MWS‑19 on apoptosis in HUVECs, an oxidative stress‑induced apoptosis model was established in HUVECs using H2O2, and the present study performed Hoechst 33258 staining and a Cell Counting Kit‑8 (CCK‑8) assay. Furthermore, western blot analysis was also performed to investigate the underlying mechanism of the effects of MWS‑19 on the model. The results demonstrated that MWS‑19 reversed the effects of H2O2 on cell apoptosis at a concentration range of 15.6‑250 µg/ml, with dose‑dependent increases in cell growth. Hoechst staining indicated that 500 µM H2O2 induced HUVEC apoptosis, and MWS‑19 markedly protected HUVECs against apoptosis at 31.3, 62.5 and 125 µg/ml. Furthermore, the protein expression of phosphatidylinositol 3‑kinase (PI3K), phosphorylated‑Akt and Bcl‑2‑associated agonist of cell death (Bad) were increased, and reduced caspase‑3 activation was observed, following treatment with MWS‑19 in H2O2‑treated HUVECs. Additionally, the PI3K inhibitor wortmannin attenuated PI3K/Akt/Bad signaling induced by MWS‑19 treatment and neutralized the effect of MWS‑19 on the growth of HUVECs. In conclusion, the results of the present study indicate that MWS‑19 may protect against H2O2‑induced HUVEC apoptosis via the PI3K/Akt/Bad signaling pathway. MWS‑19 may serve an important role in the prevention of oxidative damage in vascular endothelial cells in hypertension patients.

Evaluation of the Cellular and Animal Models for the Study of Antioxidant Activity: A Review

The mechanisms of antioxidant activities of phytochemicals are highly complex, so various methods to study them have been developed. However, the diverse available methods show inconsistent results. Different stressors, cell models, and animal models have been used to evaluate the antioxidant properties of phytochemicals. However, the literature still lacks a summary of the effects of different stressors, cell models, and animal models on the evaluation of antioxidant activities. Therefore, the mechanisms of action of different oxidative stimuli and the characteristics of the available cell models and animal models are summarized in this review.

Overexpression of LOXIN Protects Endothelial Progenitor Cells From Apoptosis Induced by Oxidized Low Density Lipoprotein

Human endothelial progenitor cells (hEPC) are adult stem cells located in the bone marrow and peripheral blood. Studies have indicated that hEPC play an important role in the recovery and repair of injured endothelium, however, their quantity and functional capacity is reduced in several diseases including hypercholesterolemia. Recently, it has been demonstrated that hEPC express lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and its activation by oxidized low-density lipoprotein (ox-LDL) induces cellular dysfunction and apoptosis. This study aimed to investigate whether overexpression of LOXIN, a truncated isoform of LOX-1 that acts as a dominant negative, plays a protective role against ox-LDL-induced apoptosis in hEPC. Human endothelial progenitor cells exposed to ox-LDL showed a significant increase in LOX-1 expression, and apoptosis began at ox-LDL concentrations above 50 μg/mL. All hEPC apoptosed at 200 μg/mL ox-LDL. High LOXIN expression was generated using adenoviral systems in hEPC and SiHa cells transduced with 100 colony-forming units per cell. Transduced LOXIN localized to the plasma membrane and blocked ox-LDL uptake mediated by LOX-1. Overexpression of LOXIN protected hEPC from ox-LDL-induced apoptosis, and therefore maybe a novel way of improving hEPC function and quantity. These results suggest that adenoviral vectors of LOXIN may provide a possible treatment for diseases related to ox-LDL and vascular endothelium dysfunction, including atherosclerosis.

Polyphenols from Cymbopogon citratus leaves as topical anti-inflammatory agents

ETHNOPHARMACOLOGICAL RELEVANCE

A variety of plant polyphenols have been reported to have anti-inflammatory, frequently associated with erythema, edema, hyperplasia, skin photoaging and photocarcinogenesis. Cymbopogon citratus (DC). Stapf (Poaceae) is a worldwide known medicinal plant, used in traditional medicine in inflammation-related conditions.

AIM OF THE STUDY

In this work, the anti-inflammatory potential of C. citratus infusion (CcI) and its polyphenols as topical agents was evaluated in vivo.

MATERIALS AND METHODS

The plant extract was prepared and its fractioning led two polyphenol-rich fractions: flavonoids fraction (CcF) and tannins fraction (CcT). An oil/water emulsion was developed with each active (CcI, CcF+CcT and diclofenac), pH and texture having been evaluated. Release tests were further performed using static Franz diffusion cells and all collected samples were monitored by HPLC-PDA. In vivo topical anti-inflammatory activity evaluation was performed by the carrageenan-induced rat paw edema model.

RESULTS

The texture analysis revealed statistically significant differences for all tested parameters to CcF+CcT, supporting its topical application. Release experiments lead to the detection of the phenolic compounds from each sample in the receptor medium and the six major flavonoids were quantified, by HPLC-PDA: carlinoside, isoorientin, cynaroside, luteolin 7-O-neohesperidoside, kurilesin A and cassiaoccidentalin B. The CcF+CcT formulation prompted to the higher release rate for all these flavonoids. CcI4%, CcI1% and CcF+CcT exhibited an edema reduction of 43.18, 29.55 and 59.09%, respectively.

CONCLUSIONS

Our findings highlight that CcI, containing luteolin 7-O-neohesperidoside, cassiaoccidentalin B, carlinoside, cynaroside and tannins have a potential anti-inflammatory topical activity, suggesting their promising application in the treatment of skin inflammatory pathologies.

Protective effect of trans-δ-viniferin against high glucose-induced oxidative stress in human umbilical vein endothelial cells through the SIRT1 pathway

Oxidative stress plays a critical role in the pathogenesis of diabetic vascular complications. Trans-δ-viniferin (TVN), a polyphenolic compound, has recently attracted much attention as an antioxidant exhibiting a hypoglycemic potential. In the present study, we aimed at investigating the protective effect of TVN against high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and the potential mechanism involved. We found that TVN attenuated reactive oxygen species (ROS) production, increased catalase (CAT) activity and decreased malondialdehyde (MDA) levels to ameliorate cell survival induced by 35 mM glucose. Meanwhile, it inhibited high glucose-induced apoptosis by maintaining Ca(2+) and preserving mitochondrial membrane potential (MMP) levels. The immunoblot analysis indicated that TVN efficiently regulated the cleavage of caspase family, p53, Bax and Bcl-2, all mediated by SIRT1. Furthermore, the increased level of SIRT1 induced by TVN was inhibited by nicotinamide and siRNA-medicated SIRT1 silencing (si-SIRT1), thereby confirming the significant role of SIRT1 in these events. In conclusion, our results indicated that TVN efficiently reduced oxidative stress and maintained mitochondrial function related with activating SIRT1 in high glucose-treated HUVECs. It suggested that TVN is pharmacologically promising for treating diabetic cardiovascular complications.

Cytoprotective effects of grape seed extract on human gingival fibroblasts in relation to its antioxidant potential

Cytoprotective effects of short-term treatment with grape seed extract (GSE) upon human gingival fibroblasts (hGFs) were evaluated in relation to its antioxidant properties and compared with those of a water-soluble analog of vitamin E: trolox (Tx). GSE and Tx showed comparable antioxidant potential in vitro against di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH; a stable radical), hydroxyl radical (^•OH), singlet oxygen (¹O₂), and hydrogen peroxide (H₂O₂). Pretreatment or concomitant treatment with GSE for 1 min protected hGFs from oxidative stressors, including H₂O₂, acid-electrolyzed water (AEW), and ¹O₂, and attenuated the intracellular formation of reactive oxygen species induced by H₂O₂ and AEW. Tx also reduced the H₂O₂- and AEW-induced intracellular formation of reactive oxygen species, but showed no cytoprotective effects on hGFs exposed to H₂O₂, AEW, or ¹O₂. These results suggest that the cytoprotective effects of GSE are likely exerted independently of its antioxidant potential.

Design and formulation of a topical hydrogel integrating lemongrass-loaded nanosponges with an enhanced antifungal effect: in vitro/in vivo evaluation

Lemongrass oil (LGO) is a volatile oil extracted from the leaves of Cymbopogon citratus that has become one of the most important natural oils in the pharmaceutical industry because of its diverse pharmacologic and clinical effects. However, LGO suffers from low aqueous solubility, which could lead to a reduced effect. Moreover, the instability of its major active constituent, citral, could lead to volatilization, reaction with other formulation ingredients, and consequently, skin irritation. To surmount these problems, this research aims to formulate lemongrass-loaded ethyl cellulose nanosponges with a topical hydrogel with an enhanced antifungal effect and decreased irritation. The minimal inhibitory concentration and minimal fungicidal concentration of LGO against Candida albicans strain ATC 100231, determined using the broth macrodilution method, were found to be 2 and 8 μL/mL, respectively. The emulsion solvent evaporation technique was used for the preparation of the nanosponges. The nanosponge dispersions were then integrated into carbopol hydrogels (0.4%). Nine formulations were prepared based on a 32 full factorial design employing the ethyl cellulose:polyvinyl alcohol ratio and stirring rate as independent variables. The prepared formulations were evaluated for particle size, citral content, and in vitro release. Results revealed that all the nanosponge dispersions were nanosized, with satisfactory citral content and sustained release profiles. Statistical analysis revealed that both ethyl cellulose:polyvinyl alcohol ratio and stirring rate have significant effects on particle size and percentage released after 6 hours; however, the effect of the stirring rate was more prominent on both responses. The selected hydrogel formulation, F9, was subjected to surface morphological investigations, using scanning and transmission electron microscopy, where results showed that the nanosponges possess a spherical uniform shape with a spongy structure, the integrity of which was not affected by integration into the hydrogel. Furthermore, the selected formulation, F9, was tested for skin irritation and antifungal activity against C. albicans, where results confirmed the nonirritancy and the effective antifungal activity of the prepared hydrogel.