Acanthus mollis Formulations for Transdermal Delivery: From Hydrogels to Emulsions

Topical formulations of Acanthus mollis L. leaf and the optimization of the release of their active compounds and their topical bioavailability were investigated for the first time. In vitro, the release of active compounds from three formulations-an oil-in-water cream and two hydrogels (Carbopol 940 and Pluronic F-127)-was determined using Franz diffusion cells. Detection and quantification of the compounds was performed via high-performance liquid chromatography with a photodiode array (HPLC-PDA). DIBOA, a bioactive compound of this medicinal plant, exhibited release kinetics of the Weibull model for the Carbopol and Pluronic F-127 formulation, identifying it as a potential active agent to optimize the topical distribution of the formulations. The implications extend to applications in inflammation treatment and tyrosinase inhibition, suggesting that it can make a significant contribution to addressing skin conditions, including melanoma and various inflammatory diseases.

Evaluation of Solanum linnaeanum and S. sisymbriifolium extracts for the management of Meloidogynechitwoodi

Meloidogyne chitwoodi causes significant yield losses in many crops and the chemical control measures currently used are less effective for this nematode. The activity of aqueous extracts (0.8 mg/mL) of one-month-old (R1M) and two-months-old roots and immature fruits (F) of Solanum linnaeanum (Sl) and S. sisymbriifolium cv. Sis 6001 (Ss) were tested on hatching, mortality, infectivity and reproduction of M. chitwoodi. The extracts selected reduced the hatching of second-stage juveniles (J2) (cumulative hatching of 40% for Sl R1M and 24% for Ss F) but did not affect J2 mortality. However, infectivity of J2 exposed to the selected extracts, during 4 and 7 days, was lower (3% and 0% for Sl R1M and 0% and 0% for Ss F) compared to the control (23% and 3%). Reproduction was affected only after 7 days of exposure (reproduction factor (RF) was 7 for Sl R1M and 3 for Ss F) compared to the control (RF = 11). The results suggest that the selected Solanum extracts are effective and can be a useful tool in sustainable M. chitwoodi management. This is the first report on the efficacy of S. linnaeanum and S. sisymbriifolium extracts against root-knot nematodes.

Synergistic Effect of DIBOA and Verbascoside from Acanthus mollis Leaf on Tyrosinase Inhibition

Overexpression of melanin contributes to darkening of plant and fruit tissues and skin hyperpigmentation, leading to melasma or age spots. Although melanin biosynthesis is complex and involves several steps, a single enzyme known as tyrosinase is key to regulating this process. The melanogenesis pathway is initiated by oxidation of the starting material l-tyrosine (or l-DOPA) to dopaquinone by tyrosinase; the resulting quinone then serves as a substrate for subsequent steps that eventually lead to production of melanin. Medicinal plants are considered a good source of tyrosinase inhibitors. This study investigated the tyrosinase inhibitory activity of A. mollis leaf extracts and their phytochemicals. Significant activity was verified in the ethanol extract -EEt (IC50 = 1.21 µg/mL). Additionally, a kinetic study showed that this tyrosinase inhibition occurs by DIBOA (2,4-dihydroxy-1,4-benzoxazin-3-one) and verbascoside contribution through a non-competitive reaction mechanism. A synergistic effect on tyrosinase inhibition was observed in the binary combination of the compounds. In conclusion, both EEt and a mixture of two of its phytochemicals can be effective tyrosinase inhibitors and can be used as a bleaching agent for cosmetic formulations in the future.

Forest Biomass as a Promising Source of Bioactive Essential Oil and Phenolic Compounds for Alzheimer's Disease Therapy

Alzheimer’s disease (AD) is the most common neurodegenerative disorder affecting elderly people worldwide. Currently, there are no effective treatments for AD able to prevent disease progression, highlighting the urgency of finding new therapeutic strategies to stop or delay this pathology. Several plants exhibit potential as source of safe and multi-target new therapeutic molecules for AD treatment. Meanwhile, Eucalyptus globulus extracts revealed important pharmacological activities, namely antioxidant and anti-inflammatory properties, which can contribute to the reported neuroprotective effects. This review summarizes the chemical composition of essential oil (EO) and phenolic extracts obtained from Eucalyptus globulus leaves, disclosing major compounds and their effects on AD-relevant pathological features, including deposition of amyloid-β (Aβ) in senile plaques and hyperphosphorylated tau in neurofibrillary tangles (NFTs), abnormalities in GABAergic, cholinergic and glutamatergic neurotransmission, inflammation, and oxidative stress. In general, 1,8-cineole is the major compound identified in EO, and ellagic acid, quercetin, and rutin were described as main compounds in phenolic extracts from Eucalyptus globulus leaves. EO and phenolic extracts, and especially their major compounds, were found to prevent several pathological cellular processes and to improve cognitive function in AD animal models. Therefore, Eucalyptus globulus leaves are a relevant source of biological active and safe molecules that could be used as raw material for nutraceuticals and plant-based medicinal products useful for AD prevention and treatment.

A review of the ethnomedicinal uses, chemistry, and pharmacological properties of the genus Acanthus (Acanthaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The Acanthus genus belongs to the Acanthaceae family, and its species are distributed in all continents, mainly in tropical and subtropical regions. Several traditional applications are referred to, but few scientific studies validate them. Despite this, studies in animal models corroborate some of its uses in folk medicine, such as anticancer, antidiabetic, anti-inflammatory, and antinociceptive, which encourages the research on plants of this genus.

AIM OF THE REVIEW

To our knowledge, this document is the first comprehensive review study that provides information on the geographic distribution, botanical characteristics, ethnomedicinal uses, phytochemicals, and pharmacological activities of some Acanthus species to understand the correlation between traditional uses, phytochemical, and pharmacological activities, providing perspectives for future studies.

RESULTS

In traditional medicine, Acanthus species are mainly used for diseases of respiratory, nervous and reproductive system, gastrointestinal and urinary tract, and skin illness. The most used species are A. montanus, A. ilicifolius, and A. ebracteatus. Chemical compounds (125) from different chemical classes were isolated and identified in seven species, mainly from A. ilicifolius, about 80, followed by A. ebracteatus and A. montanus, appearing with a slightly lower number with fewer phytochemical profile studies. Isolated phytoconstituents have been mainly alkaloids, phenylpropanoid glycosides, and phenylethanoids. In addition, aliphatic glycosides, flavonoids, lignan glycosides, megastigmane derivatives, triterpenoids, steroids, fatty acids, alcohols, hydroxybenzoic acids, simple phenols were also cited. Scientific studies from Acanthus species extracts and their phytoconstituents support their ethnomedical uses. Antimicrobial activity that is the most studied, followed by the antioxidant, anti-inflammatory, and anticancer properties, underlie many Acanthus species activities. A. dioscoridis, A. ebracteatus, A. hirsutus, A. ilicifolius, A. mollis, A. montanus, and A. polystachyus have studies on these activities, A. ilicifolius being the one with the most publications. Most studies were essentially performed in vitro. However, the anticancer, antidiabetic, anti-inflammatory and antinociceptive properties have been studied in vivo.

CONCLUSION

Acanthus species have remarkable phytoconstituents with different biological activities, such as antioxidant, antimicrobial, anti-inflammatory, antinociceptive, hepatoprotective, and leishmanicidal, supporting traditional uses of some species. However, many others remain unexplored. Future studies should focus on these species, especially pharmacological properties, toxicity, and action mechanisms. This review provides a comprehensive report on Acanthus genus plants, evidencing their therapeutic potential and prospects for discovering new safe and effective drugs from Acanthus species.

Inhibition of α-glucosidase by flavonoids of Cymbopogon citratus (DC) Stapf

ETHNOPHARMACOLOGICAL RELEVANCE

Leaves extracts from Cymbopogon citratus (DC) Stapf. are widely used in traditional medicine exhibiting several in vivo biological activities, including antidiabetic. Several flavonoids, including aglycones and glycosides, were reported in this plant and previous studies suggested that flavonoids may interact with targets related to diabetes.

AIM OF THE STUDY

Evaluated the hypoglycemic activity of C. citratus flavonoids through α-glucosidase inhibition and assess the structure-activity relationship using molecular docking studies.

MATERIAL AND METHODS

An infusion of C. citratus leaves and its flavonoid-rich fraction were prepared. Five flavonoids from this fraction were isolated and structurally characterized by UV spectral analysis with shift reagents, HPLC-PDA-ESI/MSⁿ and ¹H NMR. The antidiabetic potential of C. citratus infusion, its flavonoid-rich fraction, glycosylated flavonoids and aglycones was evaluated trough the in vitro inhibition of yeast α-glucosidase. Posteriorly, molecular docking of the tested flavonoids was performed to investigate its possible interactions with the α-glucosidase pocket.

RESULTS

The infusion of C. citratus, its flavonoid-rich fraction, luteolin and five flavone glycosides namely, luteolin 6-C-β-glucopyranoside (isoorientin), luteolin 7-O-neohesperidoside (ionicerin), luteolin 7-O-β-glucopyranoside (cynaroside), Luteolin 2″-O-rhamnosyl-C-(6-deoxy-ribo-hexos-3-ulosyl) (cassiaoccidentalin B), luteolin 6-C-α-arabinofuranosil-(1→2)-α-L-rhamnopyranoside (kurilesin A) showed higher inhibitory activity than the reference drug. This activity increased by the addition of a sugar moiety. However, the di-glycosides were less active than mono-glycosides. The docking studies showed interactions of sugar moieties and A or B rings with the catalytic pocket mainly through hydrogen bonds.

CONCLUSIONS

Our results corroborate the potential of C. citratus as a medicinal plant for the treatment of diabetes and revealed that its flavonoid glycosides has hypoglycemic effect and can be explored as drug candidates to act as α-glucosidase inhibitors in the treatment of diabetes.

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.

Solanum linnaeanum and Solanum sisymbriifolium as a sustainable strategy for the management of Meloidogyne chitwoodi

Root-knot nematodes (RKN), Meloidogyne spp., are important crop pests that cause severe losses in crop production worldwide, reducing both productivity and crop quality. Meloidogyne chitwoodi Golden, O'Bannon, Santo & Finley, 1980 is considered a quarantine organism by the European and Mediterranean Plant Protection Organization (EPPO) causing damage in tomato and potato crops. The development of nonchemical and sustainable management strategies to reduce nematode damage is crucial. The resistance of Solanum linnaeanum Hepper & P.-M.L. Jaeger and S. sisymbriifolium Lamarck cv. Sis 6001 to M. chitwoodi was evaluated based on gall index (GI), the Bridge & Page (1980) rating chart and reproduction factor (RF). Both plant species were resistant to M. chitwoodi. Solanum linnaeanum had an average of 519 small root swellings/plant, with 45% adult nematodes inside the roots, all males. Solanum sisymbriifolium had GI ≤ 2 and RF ≤ 1 with a high percentage (69%) of nematodes inside the roots that did not develop beyond the sexually undifferentiated second-stage. The use of S. linnaeanum as a new source of resistance is a good alternative for the control of RKN in the quest to develop nonchemical and sustainable management strategies to protect crops.

Fragaria vesca L. Extract: A Promising Cosmetic Ingredient with Antioxidant Properties

Fragaria vesca L. (F. vesca), popularly known as wild strawberry, is a plant from the Rosaceae family, found in temperate and subtropical areas of the northern hemisphere. F. vesca leaves have been shown to have antiseptic, emollient, and dermatological protection properties, due to the presence of bioactive compounds, such as flavonoids, phenolic acids, ellagitannins, and proanthocyanidins. In this study, a F. vesca extract was obtained by an optimized extraction process, and was characterized by HPLC, ROS scavenging activity, cytotoxicity assays in HaCaT cells, and tyrosinase inhibitory activity determination. The most active extract was then incorporated in a hydrogel with hydroxyethylcellulose at 2% (w/w), which was characterized at the physicochemical, stability, cytotoxicity, and ROS scavenging activity levels to evaluate its quality, safety, and efficacy. In vivo studies, human repeat insult patch testing, and an assay to determine their antioxidant efficacy, were also performed. The results showed that the Fragaria vesca extracts had antioxidant activity and that the F. vesca extract-based hydrogel exhibited cutaneous compatibility, acceptability and antioxidant efficacy, being stable, and suitable for topical application.

Bioactivity of Acanthus mollis - Contribution of benzoxazinoids and phenylpropanoids

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthus mollis is a plant native to the Mediterranean region, traditionally used as diuretic, anti-inflammatory and soothing of the mucous membranes of the digestive and urinary tract and externally as healing of wounds and burns, also demonstrating analgesic and anti-inflammatory activities. However, studies focused on its phytochemical composition as well as scientific proof of Acanthus mollis efficacy are scarce.

AIM OF THE STUDY

The proposed work aims to perform a phytochemical characterization and evaluation of the therapeutic potential of Acanthus mollis, based on biological properties that support its traditional uses.

MATERIAL AND METHODS

In this study, an 96% ethanol extract from Acanthus mollis leaves was obtained and its phytochemical composition evaluated using High Performance Liquid Chromatography with Photodiode Array Detector coupled to Electrospray Ionization Mass Spectrometry (HPLC-PDA-ESI/MSⁿ). The chemical structure of the compound isolated was elucidated using ¹H and ¹³C Nuclear Magnetic Resonance (NMR), ¹H-correlation spectroscopy (¹H-COSY), heteronuclear single quantum correlation (HSQC) and heteronuclear multiple-bond correlation (HMBC). The quantification of the constituents was performed using two external standards (2,4-dihydroxy-1,4-benzoxazin-3-one and verbascoside). The antioxidant activity was determined by the 2,2-diphenyl-1-pycrylhydrazyl (DPPH) assay. Anti-inflammatory activity was determined measuring the inhibition of nitric oxide production by RAW 264.7 macrophages stimulated with the TLR4 agonist lipopolysaccharide (LPS) and through lipoxygenase (LOX) inhibition assay. The cytotoxicity was screened on two lines (RAW 264.7 and HaCaT) using the resazurin assay.

RESULTS

Compounds such as verbascoside and its derivatives, as well as benzoxazinoids were found as the main constituents. A percentage of 5.58% was verified for the 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) derivatives. DIBOA was the main compound of the extract. Significant concentrations were also found for phenylpropanoids, which constitute about 4.39% of the total compounds identified. This extract showed antioxidant capacity against DPPH (IC₅₀ = 40.00 ± 1.59 μg/mL) and superoxide anion (IC₅₀ = 29.42 ± 1.99 μg/mL). It also evidenced anti-inflammatory potential in RAW 264.7 macrophages, presenting capacity for nitric oxide reduction (IC₅₀ = 28.01 μg/mL). Moreover, in vitro studies have shown that this extract was able to inhibit the lipoxygenase, with an IC₅₀ of 104.39 ± 4.95 µg/mL. Importantly, all effective concentrations were devoid of cytotoxicity in keratinocytes, thus highlighting the safety of the extract for the treatment of skin inflammatory related diseases. Concerning macrophages it was also possible to disclose concentrations showing anti-inflammatory activity and without cytotoxicity (up to 30 µg/mL). The benzoxazinoid DIBOA demonstrated a considerable anti-inflammatory activity suggesting its important contribution to this activity.

CONCLUSIONS

These results corroborate the anti-inflammatory properties traditionally attributed to this plant. Among the compounds identified in this study, benzoxazinoids exhibited a significant anti-inflammatory activity that was never previously described. Ethanol seems to be a good option for the extraction of these bioactive compounds, since relevant antioxidant/anti-radical and anti-inflammatory activities were found for this extract.

Acanthus mollis L. leaves as source of anti-inflammatory and antioxidant phytoconstituents

This work expands the phytochemical composition knowledge of Acanthus mollis and evaluates antioxidant and anti-inflammatory activities which could be related with its traditional uses. Extracts from leaves, obtained by sequential extraction, were screened using TLC and HPLC-PDA. The ethanol extract was the most active on DPPH assay (IC₅₀ = 20.50 μg/mL) and inhibited nitric oxide (NO) production in RAW 264.7 macrophages (IC₅₀ = 48.31 μg/mL). Significant amounts of cyclic hydroxamic and phenolic acids derivatives were detected. A lower antioxidant effect was verified for a fraction enriched with DIBOA derivatives (IC₅₀ = 163.02 μg/mL), suggesting a higher contribution of phenolic compounds for this activity in ethanol extract. However, this fraction exhibited a higher inhibition of NO production (IC₅₀ = 32.32 μg/mL), with absence of cytotoxicity. These results support the ethnomedical uses of this plant for diseases based on inflammatory processes. To our knowledge, it is the first report to the anti-inflammatory activity for DIBOA derivatives.

Urtica spp.: Phenolic composition, safety, antioxidant and anti-inflammatory activities

Urtica dioica and other less studied Urtica species (Urticaceae) are often used as a food ingredient. Fifteen hydroxycinnamic acid derivatives and sixteen flavonoids, flavone and flavonol-type glycosides were identified in hydroalcoholic extracts from aerial parts of Urtica dioica L., Urtica urens L. and Urtica membranacea using HPLC-PDA-ESI/MSⁿ. Among them, the 4-caffeoyl-5-p-coumaroylquinic acid and three statin-like 3-hydroxy-3-methylglutaroyl flavone derivatives were identified for the first time in Urtica urens and U. membranacea respectively. Urtica membranacea showed the higher content of flavonoids, mainly luteolin and apigenin C-glycosides, which are almost absent in the other species studied. In vitro, Urtica dioica exhibited greater antioxidant activity but Urtica urens exhibited stronger anti-inflammatory potential. Interestingly, statin-like compounds detected in Urtica membranacea have been associated with hypocholesterolemic activity making this plant interesting for future investigations. None of the extracts were cytotoxic to macrophages and hepatocytes in bioactive concentrations (200 and 350μg/mL), suggesting their safety use in food applications.

Flavan hetero-dimers in the Cymbopogon citratus infusion tannin fraction and their contribution to the antioxidant activity

Cymbopogon citratus (lemongrass) leaf infusion, a commonly used ingredient in Asian, African and Latin American cuisines, is also used in traditional medicine for the treatment of several pathological conditions; however, little is known about their bioactive compounds. Recent studies revealed the crucial role of the phenolic compounds namely flavonoids and tannins on the infusion bioactivity. Flavonoids have already been characterized; however the tannin fraction of lemongrass infusion is still uncharted. The aim of the present work is to characterize this fraction, and to evaluate its contribution to the antioxidant potential of this plant. Chemical characterization was achieved by HPLC-DAD-ESI/tandem MS and the antioxidant activity was evaluated using DPPH, ABTS and FRAP assays. Hetero-dimeric flavan structures have been described for the first time in lemongrass consisting of apigeniflavan or luteoliflavan units linked to a flavanone, either naringenin or eriodictyol, which may occur as aglycone or glycosylated forms. The antioxidant capacity of the fraction containing these compounds was significantly higher than the infusion, indicating its potential as a source of natural antioxidants.

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.

Sublingual immunization with the phosphate-binding-protein (PstS) reduces oral colonization by Streptococcus mutans

Bacterial ATP-binding cassette (ABC) transporters play a crucial role in the physiology and pathogenicity of different bacterial species. Components of ABC transporters have also been tested as target antigens for the development of vaccines against different bacterial species, such as those belonging to the Streptococcus genus. Streptococcus mutans is the etiological agent of dental caries, and previous studies have demonstrated that deletion of the gene encoding PstS, the substrate-binding component of the phosphate uptake system (Pst), reduced the adherence of the bacteria to abiotic surfaces. In the current study, we generated a recombinant form of the S. mutans PstS protein (rPstS) with preserved structural features, and we evaluated the induction of antibody responses in mice after sublingual mucosal immunization with a formulation containing the recombinant protein and an adjuvant derived from the heat-labile toxin from enterotoxigenic Escherichia coli strains. Mice immunized with rPstS exhibited systemic and secreted antibody responses, measured by the number of immunoglobulin A-secreting cells in draining lymph nodes. Serum antibodies raised in mice immunized with rPstS interfered with the adhesion of bacteria to the oral cavity of naive mice challenged with S. mutans. Similarly, mice actively immunized with rPstS were partially protected from oral colonization after challenge with the S. mutans NG8 strain. Therefore, our results indicate that S. mutans PstS is a potential target antigen capable of inducing specific and protective antibody responses after sublingual administration. Overall, these observations raise interesting perspectives for the development of vaccines to prevent dental caries.

Cymbopogon citratus industrial waste as a potential source of bioactive compounds

BACKGROUND

Cymbopogon citratus (Cc), commonly known as lemongrass, is a very important crop worldwide, being grown in tropical countries. It is widely used in the food, pharmaceutical, cosmetic and perfumery industries for its essential oil. Cc aqueous extracts are also used in traditional medicine. They contain high levels of polyphenols, which are known for their antioxidant and anti-inflammatory properties. Hydrodistillation of lemongrass essential oil produces an aqueous waste (CcHD) which is discarded. Therefore a comparative study between CcHD and Cc infusion (CcI) was performed to characterize its phytochemical profile and to research its antioxidant and anti-inflammatory potential.

RESULTS

HPLC-PDA/ESI-MS(n) analysis showed that CcI and CcHD have similar phenolic profiles, with CcHD presenting a higher amount of polyphenols. Additionally, both CcI and CcHD showed antioxidant activity against DPPH (EC50 of 41.72 ± 0.05 and 42.29 ± 0.05 µg mL(-1) respectively) and strong anti-inflammatory properties, by reducing NO production and iNOS expression in macrophages and through their NO-scavenging activity, in a dose-dependent manner. Furthermore, no cytotoxicity was observed.

CONCLUSION

The data of this study encourage considering the aqueous solution from Cc leaf hydrodistillation as a source of bioactive compounds, which may add great industrial value to this crop.

Gastroprotective effect of Cymbopogon citratus infusion on acute ethanol-induced gastric lesions in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Treatment of gastric ulcers with medicinal plants is quite common in traditional medicine worldwide. Cymbopogon citratus (DC) Stapf. leaves infusion has been used in folk medicine of many tropical and subtropical regions to treat gastric disturbances. The aim of this study was to assess the potential gastroprotective activity of an essential oil-free infusion from C. citratus leaves in acute gastric lesions induced by ethanol in rat.

MATERIALS AND METHODS

The study was performed on adult male Wistar rats (234.0±22.7g) fasted for 24h but with free access to water. The extract was given orally before (prevention) or after (treatment) intragastric administration of absolute ethanol. Effects of dose (28 or 56mg/kg of body weight) and time of contact of the extract with gastric mucosa (1 or 2h) were also assessed. Animals were sacrificed, being the stomachs removed and the lesions were assessed by macroscopic observation and histopathology.

RESULTS

C. citratus extract, given orally before or after ethanol, significantly (P<0.01) reduced gastric mucosal injury compared with control group (vehicle+ethanol). The effect does not appear to be dose-dependent. Results also suggested that the extract is more effective when the time of contact with gastric mucosa increases.

CONCLUSIONS

The results of this assay confirm the gastroprotective activity of C. citratus extract on experimental gastric lesions induced by ethanol, contributing for the pharmacological validation of its traditional use.

Bioactivity of Fragaria vesca leaves through inflammation, proteasome and autophagy modulation

ETHNOPHARMACOLOGICAL RELEVANCE

Fragaria vesca leaves have been used in folk medicine for the treatment of several diseases, namely gastrointestinal, cardiovascular and urinary disorders, which could be related with the potential anti-inflammatory properties of the extract. This work aims to disclose the bioactivity and the underlying action mechanism of an extract from Fragaria vesca leaves in order to support its traditional uses.

MATERIALS AND METHODS

A hydroalcoholic extract was prepared from Fragaria vesca leaves and its anti-inflammatory potential was evaluated through inhibition of nitric oxide production and expression of several pro-inflammatory proteins in lipopolysaccharide-triggered macrophages. Nitric oxide scavenger activity was also assessed using a standard nitric oxide donor. Since numerous inflammatory proteins are tightly regulated by ubiquitination and proteasomal degradation, the putative effect of the extract on these cellular proteolytic pathways was also disclosed. The phytochemical characterization was performed by HPLC-PDA-ESI/MSn and compared with an infusion prepared according to the traditional method.

RESULTS

For non-cytotoxic concentrations (80 and 160µg/mL) the extract inhibited nitrite production, probably due to a direct nitric oxide scavenging. Furthermore, inhibition of proteasome activity was verified, leading to accumulation of ubiquitinated proteins. The extract also increased the conversion of the microtubule-associated protein light chain LC3-I to LC3-II, a marker of autophagy. Polyphenols, namely ellagitannins, proanthocyanidins, and quercetin and kaempferol glucuronide derivatives were identified in Fragaria vesca leaves extract. Most of the identified phenolic compounds matched with those found in traditional preparation, the infusion.

CONCLUSIONS

The extract has a direct nitric oxide scavenging activity giving support to the traditional use of this plant for the treatment of inflammatory disorders. Furthermore, the extract affects the proteolytic systems but its role in cancer treatment requires further studies.

Advance in methods studying the pharmacokinetics of polyphenols

Significant advances have been achieved during the past decade concerning the metabolism of polyphenol compounds in vitro, but scarce data has been presented about what really happens in vivo. Many studies on polyphenols to date have focused on the bioactivity of one specific molecule in aglycone form, often at supraphysiological doses, whereas foods contain complex, often poorly characterized mixtures with multiple additive or interfering activities. Whereas most studies up to the middle-late 1990s measured total aglycones in plasma and urine, after chemical or enzymatic deconjugation, or both, several recent works now report the polyphenol conjugate composition of plasma, urine, feces and/or tissues, after the administration of pure polyphenols or polyphenol-rich matrices. HPLC methods with electrochemical, mass spectrometric and fluorescence detection have adequate sensitivity. LC/UV-Vis methods have also been widely reported, but they are much less sensitive. Compared with electro-chemical and fluorescence detection, MS can quantify analytes without chromatographic separation, which leads to high throughput, presenting itself as the best choice to date. Regarding the experimental model to monitor the bioavailability of phenolic compounds, most published studies are based on human and animal models, with the majority using rodents, primates and recently the nematode Caenorhabditis elegans. This review focuses on the fundamentals of pharmacokinetic methods from the last 15 years and how the results are evaluated and validated. The types of analytical methods, animal models and biological matrices were used to better elucidate pharmacokinetics of polyphenols.

Screening and identification of neuroprotective compounds relevant to Alzheimer׳s disease from medicinal plants of S. Tomé e Príncipe

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer׳s disease (AD) neuropathology is strongly associated with the activation of inflammatory pathways, and long-term use of anti-inflammatory drugs reduces the risk of developing the disease. In S. Tomé e Príncipe (STP), several medicinal plants are used both for their positive effects in the nervous system (treatment of mental disorders, analgesics) and their anti-inflammatory properties. The goal of this study was to determine whether a phenotypic, cell-based screening approach can be applied to selected plants from STP (Voacanga africana, Tarenna nitiduloides, Sacosperma paniculatum, Psychotria principensis, Psychotria subobliqua) in order to identify natural compounds with multiple biological activities of interest for AD therapeutics.

MATERIALS AND METHODS

Plant hydroethanolic extracts were prepared and tested in a panel of phenotypic screening assays that reflect multiple neurotoxicity pathways relevant to AD-oxytosis in hippocampal nerve cells, in vitro ischemia, intracellular amyloid toxicity, inhibition of microglial inflammation and nerve cell differentiation. HPLC fractions from the extract that performed the best in all of the assays were tested in the oxytosis assay, our primary screen, and the most protective fraction was analyzed by mass spectrometry. The predominant compound was purified, its identity confirmed by ESI mass spectrometry and NMR, and then tested in all of the screening assays to determine its efficacy.

RESULTS

An extract from the bark of Voacanga africana was more protective than any other plant extract in all of the assays (EC50s≤2.4 µg/mL). The HPLC fraction from the extract that was most protective against oxytosis contained the alkaloid voacamine (MW=704.90) as the predominant compound. Purified voacamine was very protective at low doses in all of the assays (EC50s≤3.4 µM).

CONCLUSION

These findings validate the use of our phenotypic screening, cell-based assays to identify potential compounds to treat AD from plant extracts with ethnopharmacological relevance. Our study identifies the alkaloid voacamine as a major compound in Voacanga africana with potent neuroprotective activities in these assays.

Propolis and its constituent caffeic acid suppress LPS-stimulated pro-inflammatory response by blocking NF-κB and MAPK activation in macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a bee product with numerous biological and pharmacological properties, such as immunomodulatory and anti-inflammatory activities. It has been used in folk medicine as a healthy drink and in food to improve health and prevent inflammatory diseases. However, little is known about its mechanism of action. Thus, the goal of this study was to verify the antioxidant activity and to explore the anti-inflammatory properties of propolis by addressing its intracellular mechanism of action. Caffeic acid was investigated as a possible compound responsible for propolis action.

MATERIALS AND METHODS

The antioxidant properties of propolis and caffeic acid were evaluated by using the 2,2-Diphenyl-1-picrylhydrazyl free radical (DPPH) scavenging method. To analyze the anti-inflammatory activity, Raw 264.7 macrophages were treated with different concentrations of propolis or caffeic acid, and nitric oxide (NO) production, a strong pro-inflammatory mediator, was evaluated by the Griess reaction. The concentrations of propolis and caffeic acid that inhibited NO production were evaluated on intracellular signaling pathways triggered during inflammation, namely p38 mitogen-activated protein kinase (MAPK), c-jun NH2-terminal kinase (JNK1/2), the transcription nuclear factor (NF)-κB and extracellular signal-regulated kinase (ERK1/2), through Western blot using specific antibodies. A possible effect of propolis on the cytotoxicity of hepatocytes was also evaluated, since this product can be used in human diets.

RESULTS

Caffeic acid showed a higher antioxidant activity than propolis extract. Propolis and caffeic acid inhibited NO production in macrophages, at concentrations without cytotoxicity. Furthermore, both propolis and caffeic acid suppressed LPS-induced signaling pathways, namely p38 MAPK, JNK1/2 and NF-κB. ERK1/2 was not affected by propolis extract and caffeic acid. In addition, propolis and caffeic acid did not induce hepatotoxicity at concentrations with strong anti-inflammatory potential.

CONCLUSIONS

Propolis exerted an antioxidant and anti-inflammatory action and caffeic acid may be involved in its inhibitory effects on NO production and intracellular signaling cascades, suggesting its use as a natural source of safe anti-inflammatory drugs.

Anti-inflammatory activity of Cymbopogon citratus leaves infusion via proteasome and nuclear factor-κB pathway inhibition: contribution of chlorogenic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (DC.) Stapf leaves infusion is used in traditional medicine for the treatment of inflammatory conditions, however little is known about their bioactive compounds.

AIM OF THE STUDY

Investigate the compounds responsible for anti-inflammatory potential of Cymbopogon citratus (Cy) on cytokines production induced by lipopolysaccharide (LPS) in human and mouse macrophages, and the action mechanisms involved.

MATERIALS AND METHODS

An essential oil-free infusion of Cy was prepared and polyphenol-rich fractions (PFs) were obtained from it by column chromatography. Chlorogenic acid (CGA) was identified, by HPLC/PDA/ESI-MS(n). The expression of cytokines, namely TNF-α and CCL5, was analyzed by real-time RT-PCR, on LPS-stimulated human macrophages. Activation of nuclear factor (NF)-κB, a master regulator of inflammation, was investigated by western blot and gene reporter assay. Proteasome activity was assessed using a fluorogenic peptide.

RESULTS

Cymbopogon citratus extract and its polyphenols inhibited the cytokine production on human macrophages. This supports the anti-inflammatory activity of Cy polyphenols in physiologically relevant cells. Concerning the effect on the activation of NF-κB pathway, the results pointed to an inhibition of LPS-induced NF-κB activation by Cy and PFs. CGA was identified, by HPLC/PDA/ESI-MS(n), as the main phenolic acid of the Cy infusion, and it demonstrated to be, at least in part, responsible by that effect. Additionally, it was verified for the first time that Cy and PFs inhibited the proteasome activity, a complex that controls NF-κB activation, having CGA a strong contribution.

CONCLUSIONS

The results evidenced, for the first time, the anti-inflammatory properties of Cymbopogon citratus through proteasome inhibition and, consequently NF-κB pathway and cytokine expression. Additionally, Cy polyphenols, in particular chlorogenic acid, were highlighted as bioactive compounds.

Cymbopogon citratus as source of new and safe anti-inflammatory drugs: bio-guided assay using lipopolysaccharide-stimulated macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Aqueous extracts of Cymbopogon citratus (Cy) leaves are used in traditional medicine for the treatment of inflammatory conditions, however, little is known about their mechanism of action.

AIM OF THE STUDY

The aim of this study is to explore the anti-inflammatory properties of Cymbopogon citratus leaves and their polyphenol-rich fractions (PFs), as well its mechanism of action in murine macrophages.

MATERIALS AND METHODS

A lipid- and essential oil-free infusion of Cy leaves was prepared (Cy extract) and fractionated by column chromatography. Anti-inflammatory properties of Cy extract (1.115 mg/ml) and its PFs, namely phenolic acids (530 μg/ml), flavonoids (97.5 μg/ml) and tannins (78 μg/ml), were investigated using lipopolysaccharide (LPS)-stimulated Raw 264.7 macrophages as in vitro model. As inflammatory parameters, nitric oxide (NO) production was evaluated by Griess reaction, as well as effects on cyclooxygenase-2 (COX-2), inducible NO synthase (iNOS) expression and on intracellular signaling pathways activation, which were analyzed by Western blot using specific antibodies.

RESULTS

Cy extract inhibited iNOS expression, NO production and various LPS-induced pathways like p38 mitogen-activated protein kinase (MAPK), c-jun NH(2)-terminal kinase (JNK) 1/2 and the transcription nuclear factor (NF)-κB. The extracellular signal-regulated kinase (ERK) 1/2 and the phosphatidylinositol-3-kinase (PI3K)/Akt activation were not affected by Cy extract. Both phenolic acid- and tannin-rich fractions significantly inhibited NF-κB activation, iNOS expression and NO production but none of the PFs modulated MAPKs or PI3K/Akt activation. Neither Cy extract nor PFs affected LPS-induced COX-2 expression but LPS-induced PGE(2) production is inhibited by Cy extract and by phenolic acid-rich fraction.

CONCLUSIONS

Our data provide evidence that support the usage of Cymbopogon citratus leaves extract in traditional medicine, and suggest that Cy, in particular its polyphenolic compounds, could constitute a natural source of a new and safe anti-inflammatory drug.

Anti-inflammatory activity of Cymbopogon citratus leaf infusion in lipopolysaccharide-stimulated dendritic cells: contribution of the polyphenols

Cymbopogon citratus, an herb known worldwide as lemongrass, is widely consumed as an aromatic drink, and its fresh and dried leaves are currently used in traditional cuisine. However, little is known about the mechanism of action of C. citratus, namely, the anti-inflammatory effects of its dietary components. Because nitric oxide (NO), produced in large quantities by activated inflammatory cells, has been demonstrated to be involved in the pathogenesis of acute and chronic inflammation, we evaluated the effects of the infusion of dried leaves from C. citratus, as well as its polyphenolic fractions--flavonoid-, tannin-, and phenolic acid-rich fractions (FF, TF, and PAF, respectively)--on the NO production induced by lipopolysaccharide (LPS) in a skin-derived dendritic cell line (FSDC). C. citratus infusion significantly inhibited the LPS-induced NO production and inducible NO synthase (iNOS) protein expression. All the polyphenolic fractions tested also reduced the iNOS protein levels and NO production stimulated by LPS in FSDC cells, without affecting cell viability, with the strongest effects being observed for the fractions with mono- and polymeric flavonoids (FF and TF, respectively). Our results also indicated that the anti-inflammatory properties of FF are mainly due to luteolin glycosides. In conclusion, C. citratus has NO scavenging activity and inhibits iNOS expression and should be explored for the treatment of inflammatory diseases, in particular of the gastrointestinal tract.

Effect and analysis of phenolic compounds during somatic embryogenesis induction in Feijoa sellowiana Berg

The effect of phenolic compounds on somatic embryogenesis in Feijoa sellowiana was analysed. The results showed that caffeic acid (140-560 microM) significantly increased somatic embryogenesis induction compared with the control. The presence of phloridzin, even at lower concentrations (11.5 microM), or caffeic acid or phloroglucinol at concentrations greater than 140.0 and 197.5 microM, respectively, inhibited somatic embryo development beyond the globular stage. When somatic embryos were transferred to the germination medium, the highest rates of germination (81.9%) were obtained with embryos induced in the presence of phloroglucinol (79.0 microM). At all concentrations tested, somatic embryos induced in medium containing phloroglucinol germinated at higher rates than those induced in the presence of caffeic acid. Histological and ultrastructural studies showed that somatic embryos were formed in close association with phenolic-rich cells which, in more advanced stages of development, formed a zone isolating the embryo from the maternal tissue. A comparative analysis of total phenolic content indicated that phenolics reached a peak by the third week of culture, independently of the medium used. However, after that period, the amount of phenolic compounds was significantly higher in explants cultured in the presence of phloroglucinol than in those cultured in the control or in caffeic acid-containing medium. Attempts to identify the type of phenolic compounds showed that flavan-3-ols and gallic acid derivatives were mainly produced in phloroglucinol-containing medium, whereas flavanones and dihydroflavonols were also present in medium containing caffeic acid. Flavones were the main phenols detected in the control. The ways in which phenolic compounds may affect somatic embryogenesis are discussed.

The activity of an extract and fraction of Agrimonia eupatoria L. against reactive species

Agrimonia eupatoria L. (agrimony) is a medicinal plant largely used in traditional medicine. Recently, phytochemical studies on an agrimony hydro-alcoholic extract and a polyphenol-enriched fraction obtained from it were carried out. The fraction was found to possess a high concentration of flavan-3-ols, flavonols, flavones and phenolic acids. So, the main purpose of this study was to search out, the extract and fraction antioxidant potential and scavenging activity against the reactive species formed during inflammation and to establish a relationship between such activity and the phenolic composition. Results showed that both the extract and the fraction promptly reacted with DPPH denoting a general radical scavenger activity and a potential antioxidant capacity. They also reacted with superoxide anion, peroxyl and hydroxyl radicals as well as with the oxidant species, hydrogen peroxide, hypochlorous acid and peroxynitrite, strengthening their radical scavenger and antioxidant activities. In most assays, the polyphenol-enriched fraction was more efficient, pointing to a significant contribution of the polyphenols content to those activities. Our data suggest that the significant scavenging capacity of reactive species by polyphenols from Agrimonia eupatoria L., could be a mechanism of its anti-inflammatory activity.

Neuropharmacological evaluation of the putative anxiolytic effects ofPassiflora edulis Sims, its sub-fractions and flavonoid constituents

Passiflora edulis Sims together with several other plants of the genus Passiflora have been reported to possess anxiolytic properties. It has been suggested recently that flavonoids may be partly responsible for the neuropharmacological activity of these plants but there are still few data reporting the relation between the constituents of these plants and their activity. This work evaluated the anxiolytic/sedative activity of an aqueous extract of Passiflora edulis Sims and bioguided its fractionation using the elevated plus-maze model of anxiety and other complementary pharmacological tests. The aqueous extract presented an anxiolytic-like activity without any significant effect upon the motor activity whilst the total flavonoid fraction (TFF) presented an anxiolytic-like activity but compromised motor activity. Through fractionation of TFF it was possible to isolate and characterize luteolin-7-O-[2-rhamnosylglucoside] which showed an anxiolytic-like activity without compromising motor activity.

Characterisation of polyphenols by HPLC-PAD-ESI/MS and antioxidant activity in Equisetum telmateia

The antioxidant activity of an aqueous extract (infusion) and respective ethyl acetate fraction of Equisetum telmateia Ehrh. (Equisetaceae), a plant used in traditional medicine for its anti-inflammatory and diuretic properties, has been evaluated by DPPH, TEAC and TBARS assays. A high and significant antioxidant activity was detected in the ethyl acetate fraction. Analysis of the aqueous extract and the ethyl acetate fraction by HPLC-PAD-ESI/MS allowed the identification of the major phenolic compounds as flavan-3-ol, kaempferol and phenolic acid derivatives. Among the flavan-3-ols, A-type proanthocyanidins and afzelechin derivatives were detected as well as the more common B-type procyanidins, B2 and C1, whose identification was further confirmed by HPLC using detection involving chemical reaction with p-dimethylamino-cinnamaldehyde. The results suggest that the anti-inflammatory activity of E. telmateia could be due, at least in part, to the presence of compounds with antioxidant activity.

Polyphenolic profile characterization ofAgrimonia eupatoria L. by HPLC with different detection devices

Liquid chromatography coupled to diode array and electrospray ionization mass spectrometry detection was used to establish the polyphenolic profile of an ethyl acetate fraction from Agrimonia eupatoria L. aqueous-alcoholic extract. Additionally, an HPLC technique with post-column derivatization by p-dimethylaminocinnamaldehyde was employed for the selective detection and quantification of flavan-3-ols. Important information was obtained by combining the data of these two HPLC techniques. Flavan-3-ols (catechin and procyanidins B1, B2, B3, B6, B7, C1, C2 and epicatechin-epicatechin-catechin), quercetin 3-O-glucoside, quercetin 3-O-galactoside, kaempferol 3-O-glucoside, kaempferol 3-O-(6''-O-p-coumaroyl)-glucoside, apigenin 6-C-glucoside and various phenolic acids were identified. Antioxidant activity of the Agrimonia eupatoria L. fraction containing these compounds was assessed through the 1,1-diphenyl-2-picrylhydrazyl, trolox equivalent antioxidant capacity and thiobarbituric acid reactive substances methods. Significant activity was observed for this fraction, where compounds with recognized antiinflammatory properties such as procyanidins, kaempferol 3-O-(6''-O-p-coumaroyl)-glucoside and quercetin glycosides were identified for the first time. These results are predictive of the beneficial effects of this fraction, or some of its compounds, in human health, as possible anti-inflammatory drug.

Antioxidant properties of proanthocyanidins of Uncaria tomentosa bark decoction: a mechanism for anti-inflammatory activity

Decoctions prepared from the bark of Uncaria tomentosa (cat's claw) are widely used in the traditional Peruvian medicine for the treatment of several diseases, in particular as a potent anti-inflammatory agent. Therefore, the main purpose of this study was to determine if the well-known anti-inflammatory activity of cat's claw decoction was related with its reactivity with the oxidant species generated in the inflammatory process and to establish a relationship between such antioxidant ability and its phenolic composition. We observed that the decoction prepared according to the traditional Peruvian medicine presented a potent radical scavenger activity, as suggested by its high capacity to reduce the free radical diphenylpicrylhydrazyl, and by its reaction with superoxide anion, peroxyl and hydroxyl radicals as well as with the oxidant species, hydrogen peroxide and hypochlorous acid. It also protected membrane lipids against peroxidation induced by the iron/ascorbate system, as evaluated by the formation of thiobarbituric acid-reactive substances (TBARs). The decoction phenolic profile was established by chromatographic analysis (HPLC/DAD and TLC) revealing essentially the presence of proanthocyanidins (oligomeric procyanidins) and phenolic acids, mainly caffeic acid. Thus, our results provide evidence for an antioxidant mechanism underlying the anti-inflammatory activity of cat's claw and support some of the biological effects of proanthocyanidins, more exactly its antioxidant and radical scavenging activities.