Hispidulin: antioxidant properties and effect on mitochondrial energy metabolism

Bioactive strawberry fruit (Arbutus unedo L.) extract remedies paraquat-induced neurotoxicity in the offspring prenatally exposed rats

Background

Paraquat (1,1'-dimethyl-4-4'-bipyridinium dichloride) exposure is well-established as a neurotoxic agent capable of causing neurological deficits in offspring. This study aimed to investigate therapeutic effects of Arbutus unedo L. aqueous extract (AU) against paraquat (PQ) exposure.

Methods

For that the phytoconstituents of AU was determined by LC/MS, and then its antioxidant potential was assessed by DPPH and ABTS assays. The assessment included its impact on cell viability and mitochondrial metabolism using N27 dopaminergic cells. Additionally, we evaluated the effects of prenatal PQ exposure on motor coordination, dopamine levels, trace element levels, and total antioxidant capacity (TAC) in rat progeny.

Results

The phytochemical profile of AU extract revealed the presence of 35 compounds, primarily phenolic and organic acids, and flavonoids. This accounted for its strong in vitro antioxidant activities against DPPH and ABTS radicals, surpassing the activities of vitamin C. Our findings demonstrated that AU effectively inhibited PQ-induced loss of N27 rat dopaminergic neural cells and significantly enhanced their mitochondrial respiration. Furthermore, daily post-treatment with AU during the 21 days of the rat's pregnancy alleviated PQ-induced motor deficits and akinesia in rat progeny. These effects inhibited dopamine depletion and reduced iron levels in the striatal tissues. The observed outcomes appeared to be mediated by the robust antioxidant activity of AU, effectively counteracting the PQ-induced decrease in TAC in the blood plasma of rat progeny. These effects could be attributed to the bioactive compounds present in AU, including phenolic acids such as gallic acid and flavonoids such as quercetin, rutin, apigenin, glucuronide, and kaempferol, all known for their potent antioxidant capacity.

Discussion

In conclusion, this preclinical study provided the first evidence of the therapeutic potential of AU extract against PQ-induced neurotoxicity. These findings emphasize the need for further exploration of the clinical applicability of AU in mitigating neurotoxin-induced brain damage.

Hispidulin Inhibits the Vascular Inflammation Triggered by Porphyromonas gingivalis Lipopolysaccharide

Hispidulin is a natural bioactive flavonoid that has been studied for its potential therapeutic properties, including its anti-inflammatory, antioxidant, and neuroprotective effects. The aim of this study was to explore whether hispidulin could inhibit the endothelial inflammation triggered by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). The adhesion of monocytes to the vascular endothelium was evaluated through in vitro and ex vivo monocyte adhesion assays. We analyzed the migration of monocytes across the endothelial layer using a transmigration assay. The results showed that treatment with hispidulin decreased the P. gingivalis LPS-induced adhesion of monocytes to endothelial cells and their migration by suppressing the P. gingivalis LPS-triggered expression of intercellular adhesion molecule-1 (ICAM-1) through downregulating nuclear factor-қB (NF-қB). In addition, hispidulin inhibited P. gingivalis LPS-induced mitogen-activated protein kinases (MAPKs) and AKT in endothelial cells. Altogether, the results indicate that hispidulin suppresses the vascular inflammation induced by P. gingivalis LPS. Mechanistically, it prevents the adhesion of monocytes to the vascular endothelium and migration and inhibits NF-қB, MAPKs, and AKT signaling in endothelial cells.

Therapeutic Potential of Leaves from Fridericia chica (Bonpl.) L. G. Lohmann: Botanical Aspects, Phytochemical and Biological, Anti-Inflammatory, Antioxidant and Healing Action

Plants of the species Fridericia chica (Bonpl.) L. G. Lohmann (Bignoniaceae), which are widely distributed in Brazil and named crajiru in the state of Amazonas, are known in folk medicine as a traditional medicine in the form of a tea for the treatment of intestinal colic, diarrhea, and anemia, among other diseases. The chemical analysis of extracts of the leaves has identified phenolic compounds, a class of secondary metabolites that provide defense for plants and benefits to the health of humans. Several studies have shown the therapeutic efficacy of F. chica extracts, with antitumor, antiviral, wound healing, anti-inflammatory, and antioxidant activities being among the therapeutic applications already proven. The healing action of F. chica leaf extract has been demonstrated in several experimental models, and shows the ability to favor the proliferation of fibroblasts, which is essential for tissue repair. The anti-inflammatory activity of F. chica has been clearly demonstrated by several authors, who suggest that it is related to the presence of 3-deoxyanthocyanidins, which is capable of inhibiting pro-inflammatory pathways such as the kappa B (NF-kB) nuclear transcription factor pathway. Another important effect attributed to this species is the antioxidant effect, attributed to phenolic compounds interrupting chain reactions caused by free radicals and donating hydrogen atoms or electrons. In conclusion, the species Fridericia chica has great therapeutic potential, which is detailed in this paper with the objective of encouraging new research and promoting the sum of efforts for the inclusion of herbal medicines in health systems around the world.

Cancer Chemopreventive Potential and Chemical Profiling of Euphorbia abyssinica Endowed with Docking Studies

Chemical profiling of both fruit and aerial part extracts of Euphorbia abyssinica via ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) showed them to be a rich source of diverse compounds. A total of 39 compounds in both extracts including flavonoids and phenolic compounds were identified as predominant metabolites. The antioxidant activity of both extracts was evaluated using three different in vitro assays (DPPH, ABTS, and FRAP assays). The E. abyssinica fruit extract demonstrated more potent activity compared to the aerial part extract (IC₅₀ of 85.1 ± 1.07 and 562.3 ± 1.01 μg/mL, respectively) in the DPPH assay. Furthermore, using ABTS and FRAP assays, the antioxidant capacities of the fruit extract were 1063.03 ± 37.8 and 1476.5 ± 95.6, respectively, calculated as μM Trolox equivalent/mg extract. One of the existing markers for cancer chemoprevention is the induction of phase II detoxifying enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1), which plays a vital role in cytoprotection against oxidative damage. The extracts were assessed to test their chemopreventive potential via NQO1 enzyme induction. The methanolic extract of fruits demonstrated a concentration-dependent increase in the cancer chemopreventive marker enzyme NQO1 at the protein expression level in a murine hepatoma cell line (Hepa1c1c7). The interaction with Kelch-like ECH-associated protein 1 (KEAP1) is an essential transcription factor that controls the expression of the NQO1 enzyme. The demonstrated induction of NQO1 by the fruit extract is consistent with a molecular docking study of the effect of dereplicated compounds on the KEAP1 target. Among the dereplicated compounds, hesperidin, naringin, and rutin have been established as promising inducer compounds for the chemopreventive marker NQO1. Our results highlight the E. abyssinica fruit extract as a future chemopreventive lead.

Antioxidant properties of hispidulin

There are conflicting reports on the antioxidant activity of hispidulin. Antioxidant activity of hispidulin was evaluated using assays of ABTS^• reduction, ferric ion reducing antioxidant power (FRAP) assay, DPPH reduction assay, and protection of erythrocyte membranes against lipid peroxidation and protein thiol oxidation. ABTS^• reduction assay pointed to the involvement of all three phenol groups of hispidulin in ABTS^• reduction. The reactivity of hispidulin in the FRAP assay and DPPH reduction assay was low (0.09 and 0.019 of the reactivity of Trolox). However, hispidulin was effective in protection against erythrocyte membrane lipid peroxidation and highly effective in protection against erythrocyte membrane protein thiol group oxidation (more effective than Trolox). These results point to the necessity of caution in extrapolating the antioxidant activity evaluated in simple cell-free systems on more complex systems.

Combined Anti-Adipogenic Effects of Hispidulin and p-Synephrine on 3T3-L1 Adipocytes

Hispidulin is abundant in Arrabidaea chica, Crossostephium chinense, and Grindelia argentina, among others. p-Synephrine is the main phytochemical constituent of Citrus aurantium. It has been used in combination with various other phytochemicals to determine synergistic effects in studies involving human participants. However, there have been no reports comparing the anti-adipogenic effects of the combination of hispidulin and p-synephrine. The current study explores the anti-adipogenic effects of hispidulin alone and in combination with p-synephrine in a murine preadipocyte cell line, 3T3-L1. Co-treatment resulted in a greater inhibition of the formation of red-labeled lipid droplets than the hispidulin or p-synephrine-alone treatments. Co-treatment with hispidulin and p-synephrine also significantly inhibited adipogenic marker proteins, including Akt, mitogen-activated protein kinases, peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, glucocorticoid receptor, and CCAAT/enhancer-binding protein β. Although further studies are required to assess the effects of each drug on pharmacokinetic parameters, a combination treatment with hispidulin and p-synephrine may be a potential alternative strategy for developing novel anti-obesity drugs.

Evaluation of cytotoxic and antioxidant potential of Dittrichia viscosa (L.) Greuter used in traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Dittrichia viscosa (L.) Greuter ("Sarı ot, Yapışkan andız otu" in Turkish) is a medicinal plant that has been traditionally used in the Mediterranean area. This plant is used by the local population for the treatment of cancer. Investigation of their biological activities is therefore very important to be supported by scientific basis for traditional use.

AIMS OF THE STUDY

In this study, it is aimed to assess the phytochemical composition, in vitro antioxidant, cytotoxic, and antiproliferative activities of the aqueous and ethanolic extracts obtained from the aerial parts (stems, leaves, flowers) of D. viscosa, collected from two sites in Turkey (Istanbul and Marmaris) against breast and prostate tumor cell lines.

MATERIALS AND METHODS

Validated methods were used to evaluate the in vitro antioxidant capacity (DPPH, ABTS, CUPRAC), cytotoxicity (Cell Viability Assay), antiproliferative (Apoptosis assay), and phytochemical compositions. The nepetin (N), 3-O-methylquercetin (Q), and hispidulin (H) in the extracts of D. viscosa were quantified by HPLC and LC-HRMS. Furthermore, in order to control the standards of benefiting from the plant in a healthy way, the contents of some heavy metals were also assessed by ICP-OES in the plant and soil samples as well as the species soil's physical and chemical characteristics.

RESULTS

We have found that heavy metal accumulation in the soil does not exceed the allowable limit value except for the nickel. The results showed that ethanol extraction is an efficient strategy to get NQH molecules with a higher content compared with other extraction techniques. However, using the same extraction method revealed that the amount of NQH molecules in the samples of two different regions were variable. The results suggested that all extracts had a high amount of total phenolic content (12.354-22.184 μg GAE/mg) and total flavonoid content (4.442-17.263 μg QE/g). In the antioxidant assay according to the DPPH method, the aqueous ethanol extracts (IC₅₀; 21.00 μg/mL) showed stronger antioxidant activity than BHT. A significant reduction in cell viability was particularly observed in MDA-MB-231 cells, which were sensitive to ethanolic extracts in Istanbul (12-22%) and in Marmaris (14-15%), while PC3 cell lines were also more sensitive to extracts of the aqueous in Istanbul (16%) and the decoction in Marmaris (12%) after 72 h. Especially, it was observed that Marmaris and Istanbul samples induced the toxicity against PC3 cells.

CONCLUSION

The study supports the medicinal use of D. viscosa as a potential anticancer against breast and prostate cancer cells in vitro and underlines the immense therapeutic potential of the plant.

Hispidulin modulates epithelial-mesenchymal transition in breast cancer cells

Breast cancer is the most commonly diagnosed cancer worldwide. Despite the use of chemotherapeutic drugs, drug resistance has been observed in numerous patients with breast cancer. Epithelial-mesenchymal transition (EMT) is an important initiation step in the process of metastasis, whereby cancer cells move away from the original tumor site. Therefore, the discovery of new substances that suppress EMT is a promising avenue for cancer treatment. The present study investigated the effect of hispidulin, a polyphenolic flavonoid, on EMT in human breast cancer cells in vitro (MCF-7 and HCC38). The EMT-associated mRNA and protein expression levels were measured using reverse transcription-quantitative PCR or western blot analysis. Hispidulin treatment increased the expression levels of EMT-associated epithelial markers and decreased the expression levels of mesenchymal markers in both cells. Transforming growth factor-β1 (TGF-β1) treatment increased breast cancer cell viability (assessed via MTS assay) and EMT induction. However, hispidulin and TGF-β1 co-treatment increased the expression levels of E-cadherin and occludin, while downregulating vimentin expression. Additionally, hispidulin treatment inhibited TGF-β1-induced Smad2/3 signaling and cell migration in both breast cancer cell lines. Overall, the current findings suggested that hispidulin may inhibit EMT and cell migration by suppressing the Smad2/3 signaling pathway in breast cancer cells.

Hispidulin: A promising flavonoid with diverse anti-cancer properties

In recent years, natural products have increasingly attracted more attention because of their potential anticancer activity and low intrinsic toxicity. Hispidulin is a natural flavonoid with a wide range of biological activities, including anti-inflammatory, antifungal, antiplatelet, anticonvulsant, anti-osteoporotic, and notably anticancer activities. Numerous in vivo and in vitro studies have shown that hispidulin, as a potential anticancer drug, affects cell proliferation, apoptosis, cell cycle, angiogenesis, and metastasis. Moreover, hispidulin exhibits synergistic anti-tumor effects when combined with some common clinical anticancer drugs (e.g., gemcitabine, 5-fluoroucil, sunitinib, temozolomide, and TRAIL). The combination of hispidulin and chemotherapeutic drugs reduces the efflux of chemotherapeutic drugs, enhances the chemosensitivity of cancer cells, and reverses drug resistance. Herein, we outlined the anticancer effects of hispidulin in various cancers and its intracellular molecular targets and related mechanisms of its anticancer activity. Based on the available literature, it can be established that hispidulin has significant potential to become an important complementary medicine for cancer prevention and treatment. However, more in-depth in vitro and in vivo studies should be conducted to support its translation from bench to bedside.

Flavonoids and Mitochondria: Activation of Cytoprotective Pathways?

A large number of diverse mechanisms that lead to cytoprotection have been described to date. Perhaps, not surprisingly, the role of mitochondria in these phenomena is notable. In addition to being metabolic centers, due to their role in cell catabolism, ATP synthesis, and biosynthesis these organelles are triggers and/or end-effectors of a large number of signaling pathways. Their role in the regulation of the intrinsic apoptotic pathway, calcium homeostasis, and reactive oxygen species signaling is well documented. In this review, we aim to characterize the prospects of influencing cytoprotective mitochondrial signaling routes by natural substances of plant origin, namely, flavonoids (e.g., flavanones, flavones, flavonols, flavan-3-ols, anthocyanidins, and isoflavones). Flavonoids are a family of widely distributed plant secondary metabolites known for their beneficial effects on human health and are widely applied in traditional medicine. Their pharmacological characteristics include antioxidative, anticarcinogenic, anti-inflammatory, antibacterial, and antidiabetic properties. Here, we focus on presenting mitochondria-mediated cytoprotection against various insults. Thus, the role of flavonoids as antioxidants and modulators of antioxidant cellular response, apoptosis, mitochondrial biogenesis, autophagy, and fission and fusion is reported. Finally, an emerging field of flavonoid-mediated changes in the activity of mitochondrial ion channels and their role in cytoprotection is outlined.

Cytotoxic effects of 4'-hydroxychalcone on human neuroblastoma cells (SH-SY5Y)

Neuroblastoma is an aggressive form of cancer with high mortality. Hydroxychalcones have received considerable attention because of their cytotoxic activities on cancer cells. However, the effect of the 4'-hydroxychalcone on neuroblastoma cells is unknown. The aim of the present study was to characterize the cytotoxicity of 4HC to neuroblastoma and the importance of mitochondrial effects in its action mechanism using an in vitro model of SH-SY5Y cells. Incubation of cultured SHSY5Y cells with 10-60 μM 4HC (24 h) decreased cell confluency, cellular metabolic activity and depleted intracellular ATP relative to the vehicle-treated control. The mechanism of 4HC-induced cell toxicity likely involves mitochondria dysfunctional as judged by inhibition of mitochondrial respiration, depolarization of mitochondria membrane potential and intracellular and morphological alterations. Furthermore, loss of cell viability was accompanied mainly by increase of phosphatidylserine exposure on the surface of cells, suggesting that the flavonoid may induce apoptosis in SH-SY5Y cells. In addition, treatment inhibited SH-SY5Y cell migration/proliferation in a scratch assay and induced significant changes in the cell cycle progression. Our results showed the effects of 4HC in the human neuroblastoma cell line SH-SY5Y are associated with mitochondrial dysfunctional, depletion of intracellular ATP levels, ROS increase, alteration in cell cycle progression and cellular morphology.

Hispidulin inhibits adipogenesis in 3T3-L1 adipocytes through PPARγ pathway

Hispidulin, a natural flavone, has been reported to have diverse pharmacological effects, including antifungal, antioxidant, and antithrombotic properties. However, an anti-adipogenic effect has not yet been reported, which is the focus of the current study. Hispidulin suppressed the differentiation of adipocytes and cellular lipid accumulation without cytotoxicity. Treatment with hispidulin at concentrations of 10, 20, and 40 μM reduced intracellular lipids by 88.1%, 81.9%, and 75.8%, respectively. In addition, hispidulin reduced mRNA and protein expression of peroxisome proliferator-activated receptor gamma (PPARγ) and adiponectin. To our knowledge, these results are the first evidence of the anti-adipogenic effects of hispidulin in 3T3-L1 adipocytes, indicating that hispidulin has potential as a novel anti-obesity therapeutic.

Protective Effect of Artemisia argyi and Its Flavonoid Constituents against Contrast-Induced Cytotoxicity by Iodixanol in LLC-PK1 Cells

Preventive effects and corresponding molecular mechanisms of mugwort (Artemisia argyi) extract and its flavonoid constituents on contrast-induced nephrotoxicity were explored in the present study. We treated cultured LLC-PK1 cells with iodixanol to induce contrast-induced nephrotoxicity, and found that A. argyi extracts ameliorated the reduction in cellular viability following iodixanol treatment. The anti-apoptotic effect of A. argyi extracts on contrast-induced nephrotoxicity was mediated by the inhibition of mitogen-activated protein kinase (MAPK) phosphorylation and the activation of caspases. The flavonoid compounds isolated from A. argyi improved the viability of iodixanol-treated cells against contrast-induced nephrotoxicity. Seven compounds (1, 2, 3, 15, 16, 18, and 19) from 19 flavonoids exerted a significant protective effect. Based on the in silico oral-bioavailability and drug-likeness assessment, which evaluate the drug potential of these compounds, compound 2 (artemetin) showed the highest oral bioavailability (49.55%) and drug-likeness (0.48) values. We further investigated the compound–target–disease network of compound 2, and proliferator-activated receptor gamma (PPAR-γ) emerged as a predicted key marker for the treatment of contrast-induced nephrotoxicity. Consequently, compound 2 was the preferred candidate, and its protective effect was mediated by inhibiting the contrast-induced inflammatory response through activation of PPAR-γ and inhibition of MAPK phosphorylation and activation of caspases.

Medicinal importance, pharmacological activities, and analytical aspects of hispidulin: A concise report

Herbal medicines have been played an important role in the human civilization since very ancient time as a food, cloth, medicine and other aspects. Some of the important drugs in the modern medicine were derived from the natural sources such as aspirin, digitalis, quinine, vincristine, vinblastine etc. Hispidulin (4', 5, 7-trihydroxy-6-methoxyflavone) is a flavones derivative found in plant such as Grindelia argentina, Arrabidaea chica, Saussurea involucrate, Crossostephium chinense, Artemisia and Salvia species. Hispidulin have antioxidant, antifungal, anti-inflammatory, antimutagenic, and antineoplastic properties. So far, various analytical methods have been investigated and developed for detection of hispidulin in the plant materials. Productions of hispidulin through different tissue culture techniques have been also investigated. Present review summarized medicinal uses, pharmacological activities and analytical aspects of hispidulin. From the above mentioned aspects, we can conclude that, this review will be helpful to the researcher in the field of natural product for the development of novel molecule for the treatment of different disorders.

The protective effect of eupafolin against TNF-α-induced lung inflammation via the reduction of intercellular cell adhesion molecule-1 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Eupafolin, a major bioactive compound found in Phyla nodiflora, has the anti-inflammatory property. Upregulation of cell adhesion molecules in the lung airway epithelium is associated with the epithelium-leukocyte interaction and plays a critical role in the pathogenesis of lung airway inflammatory disorders. To investigate the effects of eupafolin on tumor necrosis factor-α (TNF-α)-induced intercellular cell adhesion molecule-1 (ICAM-1) expression in A549 human lung airway epithelial cells and the underlying mechanisms.

MATERIALS AND METHODS

The effect of eupafolin on ICAM-1 expression in A549 cells were examined by Western blotting and immunofluorescent staining. The mice were injected intraperitoneally with or without eupafolin and then were left untreated or were injected intratracheally with TNF-α. To detect the effect of eupafolin on ICAM-1 expression, the lung tissues were also examined by Western blotting and immunohistochemical staining.

RESULTS

Eupafolin pretreatment reduced the TNF-α-induced ICAM-1 expression and also the ERK1/2, JNK, p38, and AKT/PI3K phosphorylation. However, the increase in ICAM-1 expression with TNF-α treatment was unaffected by p38 and PI3K inhibitors. Eupafolin decreased the TNF-α-induced NF-κB p65 activation and its nuclear translocation. Furthermore, eupafolin reduced ICAM-1 expression in the lung tissues of TNF-α-treated mice.

CONCLUSIONS

Eupafolin exerts its anti-inflammatory activity by suppressing the TNF-α-induced ICAM-1 expression and subsequent monocyte adhesion via AKT/ERK1/2/JNK phosphorylation and nuclear translocation of NF-κB p65. These results suggest that eupafolin may represent a novel therapeutic agent targeting epithelial activation in lung inflammation.

Protective effect of hispidulin on kainic acid-induced seizures and neurotoxicity in rats

Hispidulin is a flavonoid compound which is an active ingredient in a number of traditional Chinese medicinal herbs, and it has been reported to inhibit glutamate release. The purpose of this study was to investigate whether hispidulin protects against seizures induced by kainic acid, a glutamate analog with excitotoxic properties. The results indicated that intraperitoneally administering hispidulin (10 or 50mg/kg) to rats 30 min before intraperitoneally injecting kainic acid (15 mg/kg) increased seizure latency and decreased seizure score. In addition, hispidulin substantially attenuated kainic acid-induced hippocampal neuronal cell death, and this protective effect was accompanied by the suppression of microglial activation and the production of proinflammatory cytokines such as interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampus. Moreover, hispidulin reduced kainic acid-induced c-Fos expression and the activation of mitogen-activated protein kinases in the hippocampus. These data suggest that hispidulin has considerable antiepileptic, neuroprotective, and antiinflammatory effects on kainic acid-induced seizures in rats.

Hispidulin induces apoptosis through mitochondrial dysfunction and inhibition of P13k/Akt signalling pathway in HepG2 cancer cells

Hispidulin is a flavonoid compound which is an active ingredient in a number of traditional Chinese medicinal herbs. However, it's therapeutic activity remains poorly understood. The present study investigated the pro-apoptotic effects and mechanism by which Hispidulin induces apoptosis in human hepatoblastoma cancer (HepG2) cells. The results showed that Hispidulin induced cell death in a dose- and time-dependent manner in HepG2 cells whereas no toxic reaction was observed in normal human liver cells at indicated concentration. This study also demonstrated that Hispidulin induces apoptosis through mitochondrial dysfunction, which is characterized by decreased Bcl-2/Bax ratio, disrupted mitochondrial membrane potential and increased release of cytochrome C and activated capase-3. Our results also showed that mitochondrial dysfunction was triggered by Hispidulin-induced excessive ROS generation. Hispidulin also significantly inhibited Akt activation. ROS inhibitor NAC abrogated the inhibitory effect of Hispidulin on P13k/Akt signalling pathway and the proapoptotic effect in HepG2 cells. Our results demonstrate for the first time that Hispidulin induces apoptosis in HepG2 cells and suggested that the pro-apoptotic effect of Hispidulin was mediated through mitochondrial dysfunction and inhibition of P13k/Akt signalling pathway. Since no toxic effect was observed when normal liver cells were treated with Hispidulin, Hispidulin may have the potential to be used as therapeutic for liver cancer.

Polyphenols and mitochondria: an update on their increasingly emerging ROS-scavenging independent actions

Polyphenols, ubiquitously present in fruits and vegetables, have been traditionally viewed as antioxidant molecules. Such contention emerged, mainly from their well established in vitro ability to scavenge free radicals and other reactive oxygen species (ROS). During the last decade, however, increasing evidence has emerged supporting the ability of certain polyphenols to also exert numerous ROS-scavenging independent actions. Although the latter can comprise the whole cell, particular attention has been placed on the ability of polyphenols to act, whether favorably or not, on a myriad of mitochondrial processes. Thus, some particular polyphenols are now recognized as molecules capable of modulating pathways that define mitochondrial biogenesis (i.e., inducing sirtuins), mitochondrial membrane potential (i.e., mitochondrial permeability transition pore opening and uncoupling effects), mitochondrial electron transport chain and ATP synthesis (i.e., modulating complexes I to V activity), intra-mitochondrial oxidative status (i.e., inhibiting/inducing ROS formation/removal enzymes), and ultimately mitochondrially-triggered cell death (i.e., modulating intrinsic-apoptosis). The present review describes recent evidence on the ability of some polyphenols to modulate each of the formerly mentioned pathways, and discusses on how, by acting on such mitochondrial processes, polyphenols may afford protection against those mitochondrial damaging events that appear to be key in the cellular toxicity induced by various xenobiotics as well as that seen during the development of several ROS-related diseases.

Hispidulin attenuates bone resorption and osteoclastogenesis via the RANKL-induced NF-κB and NFATc1 pathways

Hispidulin, a flavonoid that is known to have anti-inflammatory and anti-oxidant effects, attenuates osteoclastogenesis and bone resorption. To investigate the molecular mechanism of its inhibitory effect on osteoclastogenesis, we employed the receptor activator of the nuclear factor κB (NF-κB) ligand (RANKL)-induced murine monocyte/macrophage RAW 264.7 cells and bone marrow-derived macrophages (BMMs) for osteoclastic differentiation in vitro. The inhibitory effect on in vitro osteoclastogenesis was evaluated by counting the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells and by measuring the expression levels of osteoclast-specific genes such as matrix metalloproteinase 9 (MMP9), TRAP and cathepsin K. Similarly, hispidulin significantly inhibited osteoclast activity in RAW 264.7 cell as well as stimulated the ALP activity of MC3T3E1 cells. Furthermore, the in vivo suppressive effect on bone loss was assessed quantitatively in a lipopolysaccharide (LPS)-induced mouse model using microcomputational tomography (μCT) and histochemical analyses. Hispidulin was found to inhibit RANKL-induced activation of Jun N-terminal kinase (JNK) and p38, in addition to NF-κB in vitro experiment. Additionally, hispidulin decreased NFATc1 transcriptional activity in RANKL-induced osteoclastogenesis. This study identifies hispidulin as a potent inhibitor of osteoclastogenesis and bone resorption and provides evidence for its therapeutic potential to treat diseases involving abnormal bone lysis.

Eupafolin, a flavonoid isolated from Artemisia princeps, induced apoptosis in human cervical adenocarcinoma HeLa cells

Although eupafolin, a flavone found in Artemisia princeps Pampanini, has been shown to inhibit the growth of several human cancer cells, its mode of action is poorly understood. In this study, we investigated the pro-apoptotic activities of eupafolin in human cervical carcinoma HeLa cells. It was found that eupafolin induced apoptosis in a dose-dependent manner, as evidenced by DNA fragmentation and the accumulation of positive cells for annexin V. In addition, eupafolin triggered the activations of caspases-3, -6, -7, -8, and -9 and the cleavages of their substrates, such as, poly (ADP-ribose) polymerase and lamin A/C. Furthermore, treatment with eupafolin resulted in a loss of mitochondrial membrane potential (DeltaPsi(m)), increased the release of cytochrome c to the cytosol, and altered the expression levels of B-cell lymphoma 2 (Bcl-2) family proteins. Interestingly, caspase-8, an initiator caspase, was activated after the loss of DeltaPsi(m) and the activations of caspases-3 and -9. Moreover, treatment with z-DEVD-fmk (a specific caspase-3 inhibitor) and the overexpression of Bcl-2 prevented eupafolin-stimulated caspase-8 activation. Altogether, these results suggest that the eupafolin-induced apoptosis in HeLa cells is mediated by caspase-dependent pathways, involving caspases-3, -9, and -8, which are initiated by the Bcl-2-dependent loss of DeltaPsi(m).

Quality evaluation of snow lotus (Saussurea): quantitative chemical analysis and antioxidant activity assessment

Snow lotus is commonly used as a medicinal plant and has great pharmacological value. To protect these endangered plants, in vitro propagation and cell cultures have been established in order to meet the growing market demand. The phenolic composition, antioxidant activities, total phenolic content (TPC) and total flavonoid content (TFC) from three most commonly used species, in vitro propagated lines and the cell cultures were investigated to qualify their pharmacological value. Quantitative analysis showed that the phenolics varied greatly among different species and the same species at different habitats. From this it can be inferred that the phenolics were influenced by genetic background and the environmental conditions. Significant correlations were observed between the antioxidant activity and several phenolics/TPC/TFC, suggesting that the phenolics are a major contributor of the antioxidant activity and are important for quality evaluation of snow lotus. Based on the abundance of phenolics, TPC, TFC and antioxidant activity, the order of the quality for wild species would be Saussurea involucrata > Saussurea medusa > Saussurea gossypiphora. For S. medusa, its quality judged by origin would be Shigatse > Lhasa > Nagqu. For in vitro propagated plants, the matured plants could be a reliable substitute for wild plants, and the dynamics of phenolics is critical for quality control of this monocarpic species. We provide the first report of quality comparison between the wild plants and the cell cultures. The advantages of developing cell cultures as alternatives for plants collected from the wild are discussed.

Berberine, a natural isoquinoline alkaloid, induces NAG-1 and ATF3 expression in human colorectal cancer cells

Berberine is known to possess a wide variety of pharmacological activities, including pro-apoptotic activity. However, its molecular targets are not elucidated at present. NAG-1 and ATF3 are induced by several dietary compounds associated with pro-apoptotic activity. Berberine induces cell growth arrest, apoptosis, NAG-1, and ATF3 in human colorectal cancer cells. ATF3 induction by berberine is mediated in a p53-dependent manner, whereas NAG-1 induction by berberine is mediated by multiple signaling pathways. Our results suggest that berberine facilitates apoptosis and that NAG-1 and ATF3 expression plays an important role in berberine-induced apoptosis.

Artemisia herba-alba Asso (Asteraceae) has equivalent effects to green and black tea decoctions on antioxidant processes and some metabolic parameters in rats

AIMS

The objective was to compare the long-term effects of Artemisia herba-alba Asso decoction with a green or black tea decoction, prepared without sugar, on the antioxidant processes in rats.

METHODS

The direct parameters used in the control of antioxidant processes were total antioxidant status, glutathione peroxidase activity and conjugated dienes, as early markers of lipid peroxidation. However, the indirect parameters used in this control were the body weight gains, plasma glucose and lipid concentrations, iron, copper and zinc status.

RESULTS

After 9 weeks, artemisia or tea decoctions did not influence the daily food intake of the groups; however, they significantly decreased the weight gains. They significantly increased the total antioxidant status between 83.5 and 111% and the whole blood glutathione peroxidase activity between 23 and 38%. However, only the green tea and artemisia decoctions significantly decreased the plasma conjugated diene levels by 35 and 55.5%, respectively. Regarding the trace element status, artemisia, green or black tea decoctions significantly reduced the blood Fe by 28, 30 and 17%, respectively. Also, liver Fe tended to be lower in all treated groups as compared to the control group. In contrast, artemisia significantly increased both blood and liver Cu by 50 and 28% as compared to the control group. Moreover, they significantly decreased the plasma glucose and triglyceride levels between 29 and 40%. For the cholesterol, only the artemisia decoction significantly reduced the total blood cholesterol by 17%.

CONCLUSION

Artemisia as well as green tea decoctions increased the total antioxidant status, whole blood glutathione peroxidase activity and zinc and copper status, and prevented weight gains and increases in conjugated dienes, plasma glucose, lipids and iron status. The beneficial antioxidant effects were in descending order: artemisia decoction > or = green tea decoction > black tea decoction. So, artemisia could constitute a good adjuvant to combat obesity, hyperglycemia, hypertriglyceridemia, hypercholesterolemia and particularly oxidative stress.