Inhibitory effect of luteolin 4'-O-glucoside from Kummerowia striata and other flavonoids on interleukin-5 bioactivity

Luteolin: A promising natural agent in management of pain in chronic conditions

Pain due to chronic conditions is a frequent and insufficiently addressed problem. Current drug options for pain management (either in cases of chronic inflammatory conditions or neuropathy) do not adequately treat pain. Moreover, they are associated with important adverse events in long term use. Luteolin is a flavonoid widely present in the plant kingdom and its sources have been assembled in a comprehensive list of this paper. Luteolin has shown in several research studies a range of pharmacological properties; anti-inflammatory, antioxidant, neuroprotective, and analgesic. In this article, we summarize the effects and potential benefits from introducing luteolin as an adjuvant agent in established protocols for pain management. We review the most indicative in vivo and in vitro evidence of how luteolin can target the molecular pathways involved in pathogenesis of chronic inflammatory and neuropathic pain. The data reviewed strongly support luteolin's promising benefits in pain management and raise the need for further clinical trials that can establish its role in clinical practice.

Anti-inflammatory activity and chemical composition of aqueous extract and essential oil from leaves of Ocimum selloi Benth

ETHNOPHARMACOLOGICAL RELEVANCE

The population uses the aqueous extract as tea from leaves of Ocimum selloi Benth. (alfavaca) for pain and inflammation issues. This study is motivated by a lack of data about inflammation properties of O. selloi.

AIM OF THE STUDY

This study investigated the chemical composition and anti-inflammatory activity, in mice models, of the aqueous extract (OSAE) and essential oil (OSEO) obtained from leaves of O. selloi.

MATERIALS AND METHODS

The antioxidant activity and total phenolic content were evaluated for samples, although chemical composition was obtained by U-HPLC-DAD-ESI-MS for OSAE and GC-MS for OSEO. OSAE and OSEO were tested orally at doses of 30, 100 and 300 mg/kg at the carrageenan-induced pleurisy and paw edema, also mechanical hyperalgesia, in mice.

RESULTS

Four glycosylated flavonoids and one organic acid were identified in OSAE, and nine substances in OSEO, the two majoritarian are E-anethole and methyl chavicol. Oral treatments with OSAE and OSEO significantly inhibited the carrageenan-induced pleurisy in female Swiss mice, besides OSAE and OSEO significantly prevented paw edema (after 1, 2, and 4 h), mechanical hyperalgesia (after 3 and 4 h), and cold hyperalgesia 3 h after carrageenan model in male Swiss mice. The dose of 300 mg/kg of OSEO reduced cold hyperalgesia 4 h after carrageenan.

CONCLUSION

The results evidenced the anti-inflammatory, anti-edematogenic, anti-hyperalgesic, and anti-nociceptive potentials of both materials obtained from leaves of O. selloi, mainly OSAE, supporting the popular use of this species.

Anti-allergic activities of 5,7-dimethoxy-3,4'-dihydroxyflavone via inhalation in rat allergic models

Various studies have shown that flavones have several pharmacological activities including anti-allergy activities. However, the bioavailability of oral flavones is very low, and whether inhaled administration can improve efficacy in respiratory disease models is unclear. In the present study, the anti-allergic activities of inhaling 5,7-dimethoxy-3,4'-dihydroxyflavone (MHF), a synthetic flavonoid, was investigated by comparison with disodium cromoglycate (DSCG) and nedocromil sodium (NS) in rat allergic models. In an anti-DNP-IgE-induced asthmatic model, inhaled MHF dose-dependently inhibited the increase in airway resistance after antigen challenge. In an ovalbumin (OVA)-induced asthmatic model, inhaled MHF showed significant suppression of airway hyperresponsiveness; a decrease in eosinophil and neutrophil counts, IL-4, IL-5 and leukotriene D₄ in bronchoalveolar lavage fluid; a reduction in total IgE and OVA-specific IgE levels in serum; and suppression of eosinophil infiltration in lung tissue after antigen challenge. The efficacy of inhaled MHF was comparable to that of NS and DSCG. In conclusion, based on these findings, the report for the first time that that inhaled MHF may be a potential drug for the treatment of allergic asthma.

Genetic divergence among Bradyrhizobium strains nodulating wild and cultivated Kummerowia spp. in China

Distribution of rhizobial species is affected by geographical isolation and selected by leguminous hosts, however, little is known about the molecular evolution of rhizobia nodulating the same legume in different eco-environments. In present study, the microevolution of Bradyrhizobium associated with the leguminous grass Kummerowia grown in exurban areas and cultivated in urban areas in China was investigated. Total 14 genospecies, including seven new groups, were identified based on a concatenated sequence analysis of taxonomic markers (SMc00019, truA and thrA) for 94 representative strains. Results demonstrated that lower levels of nucleotide diversity were found in the strains isolated from urban areas compared with those isolated from exurban areas, based on the evolutional analyses of three housekeeping genes (atpD, glnII and recA), two symbiosis-related genes (nodC and nifH), and the taxonomic markers. Moreover, compared with urban areas, gene exchange and recombination occurred more frequently among the genospecies isolated from exurban areas, regardless of the geographical distribution. Finally, the evolutionary lineage of Bradyrhizobium strains isolated from urban areas was independent of that of the strains isolated from exurban areas. In summary, the evolutionary history of Kummerowia bradyrhizobia may have been gradually segregated to different evolutionary lineages, irrespective of distinct biogeography.

Anti-allergic effect of luteolin in mice with allergic asthma and rhinitis

AIM OF THE STUDY

We aimed to evaluate the anti-allergic effect of luteolin treatment in mice with allergic asthma and rhinitis.

MATERIAL AND METHODS

Thirty-two BALB/c mice (n = 8 for each group) were used. Mice in group A (nonallergic group) were exposed to saline, while those in Group B (allergic group) were exposed to ovalbumin (OVA) intraperitoneal (i.p.) injection and intranasal (i.n.) challenge. Null treatment group (Group C) received sterile saline (150 μl) i.p. injection, 30 minutes before each i.n. challenge. Finally, the treatment group (Group D) received luteolin (0.1 mg/kg) by i.p. injection, 30 minutes before each i.n. challenge. We evaluated the number of inflammatory cells including eosinophils, neutrophils and lymphocytes in bronchoalveolar lavage (BAL) fluid, the titers of IL-4, IL-5 and IL-13 in lung homogenate, and we also evaluated histopathologic findings, including infiltration of inflammatory cells into the pulmonary parenchyma and nasal mucosa.

RESULTS

After the OVA challenge, the number of eosinophils, neutrophils and lymphocytes in BAL fluid was significantly increased in group B, compared to group A (p < 0.001). Mice in group C had no significant difference (p > 0.05). On the other hand, group D showed a significant decrease in all inflammatory cells compared to group B (p < 0.05). Also, group D showed a significant decrease in IL-4, IL-5 and IL-13 in their lung homogenate compared to groups B and C (p < 0.05). Group D also showed a significant decrease in inflammatory cell infiltration after luteolin treatment (p < 0.05).

CONCLUSION

Luteolin had an anti-allergic effect in a murine model of allergic asthma and rhinitis.

Nature nominee quercetin's anti-influenza combat strategy-Demonstrations and remonstrations

Nature's providences are rather the choicest remedies for human health and welfare. One such is quercetin, which is nature's nominee for cancer cure and recently demonstrated against influenza attack. Quercetin is highly recognized for its anticancer applications. This review emphasizes on yet another gift that this compound has to offer for mankind, which is none other than combating the deadly evasive influenza virus. The chemistry of this natural bioflavonoid and its derivatives and its modus operandi against influenza virus is consolidated into this review. The advancements and achievements made in the anti-influenza clinical history are also documented. Further, the challenges facing the progress of this compound to emerge as a predominant anti-influenza drug are discussed, and the future perspective for breaking its limitations through integration with nanoplatforms is envisioned.

Kaempferol-3-O-rutinoside from Afgekia mahidoliae promotes keratinocyte migration through FAK and Rac1 activation

The restoration of the epidermal epithelium through re-epithelialization is a critical process in wound healing. Directed keratinocyte migration to the wound is required, and the retardation of this process may result in a chronic, non-healing wound. The present study contributes to research aiming to identify promising compounds that promote wound healing using a human keratinocyte model. The effects of three kaempferol glycosides from an Afgekia mahidoliae leaf extract, kaempferol-3-O-arabinoside, kaempferol-3-O-glucoside, and kaempferol-3-O-rutinoside, on keratinocyte migration were determined. Interestingly, kaempferol-3-O-rutinoside exhibited a pronounced effect on wound closure in comparison to the parental kaempferol and other glycosides. The mechanism by which kaempferol-3-O-rutinoside enhances cell migration involves the induction of filopodia and lamellipodia formation, increased cellular levels of phosphorylated FAK (Tyr 397) and phosphorylated Akt (Ser 473), and up-regulation of active Rac1-GTP. The data obtained in this study may support the development of this compound for use in wound healing therapies.

Modeling natural anti-inflammatory compounds by molecular topology

One of the main pharmacological problems today in the treatment of chronic inflammation diseases consists of the fact that anti-inflammatory drugs usually exhibit side effects. The natural products offer a great hope in the identification of bioactive lead compounds and their development into drugs for treating inflammatory diseases. Computer-aided drug design has proved to be a very useful tool for discovering new drugs and, specifically, Molecular Topology has become a good technique for such a goal. A topological-mathematical model, obtained by linear discriminant analysis, has been developed for the search of new anti-inflammatory natural compounds. An external validation obtained with the remaining compounds (those not used in building up the model), has been carried out. Finally, a virtual screening on natural products was performed and 74 compounds showed actual anti-inflammatory activity. From them, 54 had been previously described as anti-inflammatory in the literature. This can be seen as a plus in the model validation and as a reinforcement of the role of Molecular Topology as an efficient tool for the discovery of new anti-inflammatory natural compounds.

Calycopterin, an immunoinhibitory compound from the extract of Dracocephalum kotschyi

Medicinal plants have been widely investigated for their various effects. Dracocephalum kotschyi Boiss (Labiatae) is used in Iranian traditional medicine for the treatment of rheumatoid diseases. The inhibitory effect of D. kotschyi on the lectin-induced cellular immune response has been demonstrated previously. In this study, mitogen-treated lymphocytes were exposed to the extract of D. kotschyi and analysed for the induction of apoptosis using flow cytometry and gel electrophoresis. The data obtained indicated a dose-dependent increase of cells in the sub-G1 phase of cell cycle. Study of internucleosomal DNA fragmentation showed a typical DNA laddering in agarose gels. A bioactivity-guided fractionation assay to find the active components responsible for the inhibitory effect of D. kotschyi on mitogen-induced lymphocyte proliferation led to the isolation of calycopterin from the ethyl acetate extract of D. kotschyi. Its structure was identified by spectroscopic methods including( 1)H-NMR, (13)C-NMR, MS and UV spectra. Calycopterin inhibited lymphocyte proliferation in a dose-dependent manner with an IC(50) value of 1.7 microg/mL. In conclusion, the results of this study suggest that D. kotschyi extract has the capacity to induce apoptosis in the lymphocytes and that isolated calycopterin is responsible for the inhibitory effect of D. kotschyi on lymphocyte proliferation.

Anti-allergic effect of bee pollen phenolic extract and myricetin in ovalbumin-sensitized mice

ETHNOPHARMACOLOGICAL RELEVANCE

The bee pollen is used in folk medicine to alleviate allergic reactions. The bee pollen phenolic extract (BPPE) consists in phenolic compounds (flavonoids) from plants picked by Apis mellifera bee.

AIM OF THIS STUDY

Here we evaluated the anti-allergic property of the BPPE and the flavonoid myricetin (MYR) in murine model of ovalbumin (OVA)-induced allergy.

MATERIALS AND METHODS

The study focused on the BPPE or myricetin treatment of OVA-sensitized BALB/c mice and their effects on the IgE and IgG1 production, pulmonary cell migration, eosinophil peroxidase (EPO) activity and anaphylactic shock reaction.

RESULTS

The BPPE treatment (200mg/kg) showed inhibition of the paw edema, IgE and IgG(1) OVA-specific production, leukocyte migration to the bronchoalveolar lavage (BAL) and EPO activity in lungs. In addition, BPPE treatment showed partial protection on the anaphylactic shock reaction induced by OVA. Treatment with myricetin (5 mg/kg) also inhibited pulmonary cell migration and IgE and IgG(1) OVA-specific production.

CONCLUSIONS

These results support the hypothesis the myricetin is one of the flavonoids of BPPE responsible for the anti-allergic effect and a potential tool to treat allergies.

A HPTLC densitometric determination of luteolin in Thymus vulgaris and its extracts

Luteolin content in Thymus vulgaris and its extracts have been compared. Luteolin was separated on a thin- layer of silica gel with three-step gradient elution and determined by HPTLC-photodensitometry. The proposed method is simple and sensitive and can be used for the routine assay of luteolin in phytomedicines containing thyme extracts.

Synthesis and immunosuppressive activity of l-rhamnopyranosyl flavonoids

Astilbin, a flavonoid isolated from different plants, shows diverse biological activities. This paper reports the synthesis and immunosuppressive activity of seven analogues of astilbin, which may shed light on the structure-activity relationship of the compounds. The following glycosyl flavonoids, 6-alpha-L-rhamnopyranosyloxyflavanone (20), 3-alpha-L-rhamnopyranosyloxyflavone (22), 3-alpha-L-rhamnopyranosyloxyflavanone (24), 3-alpha-L-rhamnopyranosyloxychromanone (26), 4-alpha-L-rhamnopyranosyloxychromanol (27), 7-hydroxy-3-alpha-L-rhamnopyranosyloxyflavanone (30) and 4'-hydroxy-3-alpha-L-rhamnopyranosyloxyflavanone (32) were prepared respectively by glycosylation of 6-hydroxyflavanone (1), 3-hydroxyflavone (2), 3-hydroxyflavanone (5), 3-hydroxychromanone (8), 4-chromanol (9), 7-benzyloxy-3-hydroxyflavanone (12), 4'-benzyloxy-3-hydroxyflavanone (15). Among them, compounds 5, 8, 12 and 15 were synthesized from flavanone (3), 4-chromanone (6), 7-hydroxyflavanone (10) and 4'-hydroxyflavanone (13) respectively. Similar to astilbin (4), compounds 22, 24, 26, 30 and 32 significantly inhibited the single mixed lymphocytes reaction (sMLR) and enhanced the apoptosis of spleen cells isolated from mice with sheep red blood cell-induced delayed-type hypersensitivity respectively. However, compound 20 only showed a slight tendency to inhibit sMLR at higher concentration. Both compounds 20 and 27 did not influence the cell apoptosis. These data suggest that the following factors play essential roles in determining the biological activity of the flavonoids: the position at which the sugar is linked to the flavone, the presence of carbonyl on C-4 and phenol hydroxyl group in A or B ring. However, the presence of a B ring is unfavorable for the biological activity and the double bond at C2-C3 in C-ring shows little effect on the activity.

Salix caprea inhibits skin carcinogenesis in murine skin: inhibition of oxidative stress, ornithine decarboxylase activity and DNA synthesis

Chemoprevention of free radical-mediated diseases including cancer by natural products is an emerging discipline due to its wider applicability and acceptance. The present study deals with the chemopreventive effect of Salix caprea against phorbol ester-induced oxidative stress and tumor promotion in murine skin. In the present investigation, it was observed that a single application of 12-O-tetradecanoyl-13-phorbol acetate (TPA) (20 nmol/0.2 ml acetone/animal) caused a significant (P < 0.05) depletion of cutaneous antioxidants viz., glutathione, glutathione reductase, glutathione peroxidase, catalase and phase II drug metabolizing enzymes viz., glutathione-S-transferase, quinone reductase. An increase in the hydrogen peroxide generation and protein oxidation (measured in terms of protein carbonyl content) was also observed with a single application of TPA. However, the pretreatment of animals with different doses of Salix caprea (0.5, 1.0 and 1.5 mg/kg/0.2 ml acetone) caused a significant recovery in the TPA-mediated depletion in antioxidant levels. The pretreatment of animals with Salix caprea was observed to inhibit the TPA-mediated depletion in phase II enzymes. It was also observed that Salix caprea reversed the TPA-mediated depletion in the activity of phase II enzymes that is an important characteristic of cancer chemopreventive agents. Phorbol esters are known to induce the tumor promotion by increasing rate of DNA synthesis, ornithine decarboxylase activity (ODC), and xanthine oxidase activity. In the present investigation, it was observed that the pretreatment of animals with Salix caprea caused a significant (P < 0.05) depletion in the TPA-induced DNA synthesis, ODC and xanthine oxidase activity in mice skin. Salix caprea significantly reduced the tumor promotion in mice skin when tested in two-stage chemical carcinogenesis model. It was observed to inhibit significantly P < 0.05) the 7,12-dimethyl benz[a] anthracene (DMBA)-initiated phorbol ester promoted skin carcinogenesis. It was concluded from the results that Salix caprea is an effective antioxidant and chemopreventive agent against phorbol ester-induced tumor promotion.

Effects on blood pressure decrease in response to PAF of Impatiens textori MIQ

A 35% EtOH extract of flowers of Impatiens textori MIQ. showed an inhibitory effect on blood pressure decrease in response to platelet activating factor (PAF) measured with a blood pressure monitoring system. Bioassay-guided fractionation of the 35% EtOH extract (IT) led to isolation of the flavones apigenin (1) and luteolin (3), which significantly inhibited blood pressure decrease in response to PAF. Their compounds and apigenin 7-glucoside (2), chrysoeriol (4), quercetin (5), quercetin 3-glucoside (6), kaempferol (7), kaempferol 3-glucoside (8) and kaempferol 3-rhamnosyldiglucoside (9) were also isolated from the flowers of I. textori for the first time. This study revealed that the flowers of I. textori might be a possible anti-allergy agent.

Facile synthesis of flavonoid 7-O-glycosides

Highly regioselective removal of the 7-O-acyl groups of the peracylated flavones, isoflavones, and flavonols (PhSH, imidazole, NMP) followed by effective glycosylation with glycosyl trifluoroacetimidates (BF(3).Et(2)O) and cautious deprotection of the acyl groups under basic conditions afforded the desired 7-O-flavonoid glycosides in satisfactory yields.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

[The plant origins of herbal medicines and their quality evaluation]

The caulis (stem and leaf) of Trachelospermum jasminoides (Lindl.) Lem. (Apocynaceae) is listed as the plant origin of Luoshiteng in the Chinese Pharmacopeia. However, preparations from the caulis of Ficus pumila L. (Moraceae) or Psychotria serpens L. (Rubiaceae) are distributed on the Chinese market. The fruit of Forsythia suspensa Vahl (Oleaceae) is listed as the plant origin of Forsythia Fruit in the Chinese Pharmacopeia, although the fruits of two Forsythia species, F. suspensa and F. viridissima Lindley, are listed as the plant origins in the Japanese Pharmacopeia, and fruits of three Forsythia species, F. viridissima, F. koreana Nakai, and F. suspensa, are listed in the Korean Pharmacopeia. The whole plant of Plantago asiatica L. (Plantaginaceae) is listed as the plant origin of Plantago Herb in the Japanese Phamacopeia, but the whole plants of two Plantago species, P. asiatica and P. depressa Wild, are listed as the plant origins in the Chinese Pharmacopeia. The leaves of two Plantago species, P. lanceolata L. and P. major L., are distributed as Plantain on the European market. Each of these herbal medicines is reviewed based on the differences in plant origins and their quality evaluation from the viewpoints of the morphological properties, chemical components, and biological activities, respectively.

The flavonoid Kaempferol suppresses the graft-versus-host reaction by inhibiting type 1 cytokine production and CD8+ T cell engraftment

We have here examined the immunoregulatory effects of a natural flavonoid, Kaempferol, on T cells. Kaempferol suppressed IFN-gamma and IL-2 production but not that of IL-4 by T cells and shifted the Th1/Th2 balance into the Th2 phenotype. In C57BL/6 anti-BDF1 MLC, Kaempferol inhibited the development and expansion of type 1 effector CD8+ T cells and diminished allospecific CTL activity. Based on these in vitro results, we evaluated the effects of Kaempferol treatment on the development of C57BL/6-into-BDF1 acute graft-versus-host disease (GVHD). Brief administration of Kaempferol led to early recovery from body weight loss, increased survival, and reduced tissue injury in the liver and large intestine. Kaempferol treatment activated Th2 cells and the engraftment of donor cells and also diminished GVHD-associated antihost CTL activity. Thus, our study indicates that Kaempferol has the capacity to modulate the Th1/Th2 balance and could be useful for the treatment of cell-mediated immune diseases, such as acute GVHD.

Attenuation of benzoyl peroxide-mediated cutaneous oxidative stress and hyperproliferative response by the prophylactic treatment of mice with spearmint (Mentha spicata)

The modulating effect of spearmint (Mentha spicata) on benzoyl peroxide-induced responses of tumor promotion in murine skin was investigated. Benzoyl peroxide (BPO) is an effective cutaneous tumor promoter acting through the generation of oxidative stress, induction of ornithine decarboxylase activity and by enhancing DNA synthesis. BPO treatment (20 mg/animal) increased cutaneous microsomal lipid peroxidation and hydrogen peroxide generation. The activity of cutaneous antioxidant enzymes, namely catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase, was decreased and the level of cutaneous glutathione was depleted. BPO treatment also induced the ornithine decarboxylase activity and enhanced the [3H]thymidine uptake in DNA synthesis in murine skin. Prophylactic treatment of mice with spearmint extract (10, 15 and 20 mg/kg) 1 hr before BPO treatment resulted in the diminution of BPO-mediated damage. The susceptibility of cutaneous microsomal membrane to lipid peroxidation and hydrogen peroxide generation was significantly reduced (P < 0.05 ). In addition, depleted levels of glutathione, inhibited activity of glutathione dependent and antioxidant enzymes were recovered to a significant level (P < 0.01, P < 0.05 and P < 0.01, respectively). Similarly, the elevated ornithine decarboxylase activity and enhanced thymidine uptake in DNA synthesis was inhibited significantly (P < 0.05 ) in a dose-dependent manner. The protective effect of spearmint was dose dependent in all parameters. The result suggests that spearmint is an effective chemopreventive agent that may suppress BPO-induced cutaneous oxidative stress, toxicity and hyperproliferative effects in the skin of mice.