Anti-inflammatory and anti-edematogenic action of the Croton campestris A. St.-Hil (Euphorbiaceae) essential oil and the compound ß-caryophyllene in in vivo models.

BACKGROUND: Inflammation makes up a set of vascularized tissue reactions acting in the defense of the body against harmful stimuli. Natural products are a lower cost alternative with better benefit, often used in popular medicine in the treatment of inflammatory processes. Several species from the genus Croton have scientifically proven anti-inflammatory action. PURPOSE: This study aims to analyze the chemical composition of the Croton campestris A. St.-Hil essential oil (EOCC), derived from fresh leaves, as well as to evaluate the anti-inflammatory potential and the possible mechanisms of action of the EOCC and its constituent ß-caryophyllene. METHODS: The assays were performed in in vivo models of acute and chronic inflammation. Initially, the chemical composition of the EOCC was determined and its oral toxicity was evaluated, followed by the evaluation of its topical antiedematogenic effect through acute and chronic ear edema induced by Croton oil. For the systemic verification of an anti-inflammatory action, the abdominal contortions, formalin test, paw edema induced by carrageenan, dextran, histamine and arachidonic acid models, as well as a peritonitis test, vascular permeability and granuloma assays were performed. RESULTS: The evaluation of the essential oil chemical composition revealed the presence of ß-caryophyllene (15.91%), 1,8-cineol (16.98%) and germacrene-D (14.51%) as its main constituents. The EOCC had no relevant clinical toxicity on oral administration, with an LD50 of more than 5000 mg/kg. The tested substances showed anti-inflammatory action in the abdominal contortions, paw edema induced by carrageenan, dextran, histamine and arachidonic acid models, the formalin test, peritonitis test and vascular permeability; however, ß-caryophyllene had no significant effect on the granuloma assay. This suggests as a hypothesis that both substances tested showed significant influence on the arachidonic acid and histamine pathway reducing edema in these models. CONCLUSION: The tested substances have a clinically safe profile, additionally the EOCC and ß-caryophyllene presented relevant anti-inflammatory activity. This study supports the hypothesis that ß-caryophyllene, in association with other constituents present in the EOCC such as 1,8-cineole, contributed to the anti-inflammatory effect observed, in addition to suggesting that one of the mechanisms of action probably involves the inhibition of cytokines with the involvement of the arachidonic acid and histamine pathways.

Developmental and reproductive toxicological evaluation of arachidonic acid (ARA)-Rich oil and docosahexaenoic acid (DHA)-Rich oil.

The purpose of this study was to investigate the reproductive and developmental toxicity of dietary exposure to DHA-rich oil from Schizochytrium sp. and ARA-rich oil from Mortierella alpina. In a developmental toxicity study, pregnant Wistar rats were untreated (control) or administered corn oil (vehicle control), 1000, 2500, or 5000 mg/kg bw/day of DHA-rich oil or ARA-rich oil via gavage from gestation days 6 through 20. In the reproductive toxicity study, male and female Wistar rats were administered vehicle control (corn oil), or 1000, 2500, or 5000 mg/kg bw/day of DHA- or ARA-rich oil via gavage throughout the mating period, pregnancy, and the nursing and lactation period. Differences in the number of fetuses, fetal skeletal malformations, and external and visceral anomalies in the developmental study and mortality, clinical signs, fertility indices, physical observations, gross necropsy findings, and gestation period length in the reproductive toxicity study were not dose-related or significantly different from control groups, and were not considered to be treatment related. The no observed adverse effect level (NOAEL) for maternal toxicity and embryo/fetal development and for paternal or maternal treatment-related reproductive toxicity for the DHA-rich oil and ARA-rich oil administered by gavage, was 5000 mg/kg bw/day.

Arachidonic acid with taurine enhances pulmonary absorption of macromolecules without any serious histopathological damages.

Therapeutic peptides and protein are being used in several indications; however, their poor permeability still remains to be solved. This study focused on the pulmonary route of macromolecules. First, the effects of arachidonic acid (AA) as an absorption enhancer on drug serum concentration, after intratracheal administration, were investigated in rats. Second, the safety of AA was assessed in rats in an acute toxicity study for 7days. AA enhanced the exposure of both interferon-α (IFN-α) and fluorescein isothiocyanate 4000 (FD-4). In addition, the histopathological analysis indicated that AA caused alveolitis and bronchitis in rats. In combination with Taurine (Tau), these lung injuries were prevented through the histopathological analysis. The combined use of Tau with AA did not show any changes in the pharmacokinetics of FD-4. From these results, we suggest the combined use of AA with Tau as a novel formulation on the pulmonary route of macromolecule drugs. This formulation could improve the bioavailability of macromolecule drugs without any serious local damage to the lungs.

Zinc increases vulnerability of rat thymic lymphocytes to arachidonic acid under in vitro conditions.

Previous studies on the cytotoxicity of arachidonic acid (ARA) elucidated the involvement of oxidative stress and Ca(2+). In the present study, the Zn(2+)-related cytotoxicity of ARA was studied by a flow cytometric technique with appropriate fluorescent probes in rat thymocytes. Addition of 10 µM ZnCl2 enhanced the increase in cell lethality induced by 10 µM ARA. The removal of Zn(2+) by Zn(2+) chelators attenuated the ARA-induced increase in cell lethality. Thus, Zn(2+) is suggested to be involved in ARA cytotoxicity. ARA at 3-10 µM elevated intracellular Zn(2+) level. The Zn(2+) chelators attenuated the ARA-induced increase in intracellular Zn(2+) level while ARA significantly increased intracellular Zn(2+) level in the presence of 3 µM ZnCl2, suggesting the involvement of external Zn(2+). Zn(2+) reportedly exerts cytotoxic action under oxidative stress induced by hydrogen peroxide, via an excessive increase in intracellular Zn(2+) levels. Since ARA induces oxidative stress, the simultaneous administration of zinc and ARA may be harmful.

Toxicological evaluation of arachidonic acid (ARA)-rich oil and docosahexaenoic acid (DHA)-rich oil.

The safety of DHA-rich oil from Schizochytrium sp. and ARA-rich oil from Mortierella alpina was separately evaluated by testing for gene mutations, clastogenicity, and aneugenicity, and by conducting 28-day and 90-day dietary studies in Wistar rats. The results of all genotoxicity tests were negative. The 28-day and 90-day studies involved dietary exposure to 1000, 2500, and 5000 mg per kg bw of the DHA-rich and ARA-rich oils and two control diets: water and corn oil (vehicle control). There were no treatment-related effects of either the DHA-rich or ARA-rich oils on clinical observations, body weight, food consumption, behavior, hematology, clinical chemistry, coagulation, urinalysis parameters, or necropsy findings. Increases in cholesterol and triglyceride levels were considered related to a high oil diet and non-adverse. The no observable adverse effect level (NOAEL) for both the DHA-rich and ARA-rich oils was 5000 mg per kg bw, the highest dose tested. The results confirm that these oils possess toxicity profiles similar to those of other currently marketed oils and support the safety of DHA-rich oil from Schizochytrium sp. and ARA-rich oil from Mortierella alpina for their proposed uses in food.

[Association of red blood cell damage with arachidonic acid].

OBJECTIVE: To study the correlation between arachidonic acid (AA) and acute red blood cells damage in rats, and to build a model with hidden blood loss in vivo, and to explore the pathological mechenism of hidden blood loss. METHODS: A total of 50 male adult Sprague-Dawley rats weighing (200 ± 20) g were randomly divided into five groups (n = 10): control group and four experimental groups. The rats in the experimental groups were given 0.5 ml different concentrations of AA dilu- ents, 5, 10, 20, 40 mmol/L respectively. The blood samples were collected from orbital venous at the beginning and 24, 48, 72 hours after administration. Then the changes of hemoglobin (Hb) ,red blood cell count (RBC), glutathione peroxidase (GSH- PX) activity, total superoxide dismutase (T-SOD) activity and hydrogen peroxide (H202) in the blood samples were tested. RESULTS: Significant hidden blood loss occurred when the concentration was 10 mmol/L in the experimental group, with the RBC and Hb sharply reduced in blood samples. The Hb and RBC were reduced in all the experimental groups and control group at 24 hours after administration, while in the experimental groups they changed more obviously. The GSH-PX activity, T-SOD activity and H2O2were also significantly reduced in all groups, and the changes showed significant differences. The Hb and RBC were relatively stable in the control group and the experimental groups at 48 hours after administration; while GSH-PX activity, T-SOD activity and H2O2were all significantly decreased, and the changes in the experimental groups were more notable. CONCLUSION: Elevated levels of AA in the blood causes oxidative stress in the red blood cells, leading to the damage of red blood cells and hemoglobin, which is responsible for hidden blood loss.

Eupatilin induces Sestrin2-dependent autophagy to prevent oxidative stress.

Eupatilin (5,7-dihydroxy-3,4,6-trimethoxyflavone) has many pharmacological activities including anti-inflammation, anti-oxidant and anti-cancer effects. Autophagy is the basic cellular machinery involving the digestion of damaged cellular components. In the present study, we investigated the protection effects of eupatilin against arachidonic acid (AA) and iron-induced oxidative stress in HepG2 cells and tried to elucidate the molecular mechanisms responsible. Eupatilin increased cell viability against AA + iron in a concentration-dependent manner and prevented mitochondrial dysfunction and reactive oxygen species (ROS) production. In addition, AA + iron increased the levels of pro-apoptotic proteins and these changes were prevented by eupatilin. Eupatilin also induced autophagy, as evidenced by the accumulation of microtubule-associated protein 1 light chain3-II and the detection of autophagic vacuoles. Furthermore, the protective effects of eupatilin on mitochondrial dysfunction and ROS production were significantly abolished by autophagy inhibitors. Eupatilin also increased the mRNA level of sestrin-2 and its promoter-driven reporter gene activity, which resulted in the up-regulation of sestrin-2 protein. Finally, gene silencing using sestrin-2 siRNA and the ectopic expression of recombinant adenoviral sestrin-2 indicated that sestrin-2 induction by eupatilin was required for autophagy-mediated cytoprotection against AA + iron. Our results suggest that eupatilin activates sestrin-2-dependent autophagy, thereby preventing oxidative stress induced by AA + iron.

A three-dimensional model of primary bovine endometrium using an electrospun scaffold.

Endometrial stromal and epithelial cell function is typically studied in vitro using standard two-dimensional monocultures, but these cultures fail to reflect the complex three-dimensional (3D) architecture of tissue. A 3D model of bovine endometrium that reflects the architectural arrangement of in vivo tissue would beneficially assist the study of tissue function. An electrospun polyglycolide (PGA) scaffold was selected to grow a 3D model of primary bovine endometrial epithelial and stromal cells, that reflects the architecture of the endometrium for the study of pathophysiology. Electrospun scaffolds were seeded with stromal and epithelial cells, and growth was assessed using histological techniques. Prostaglandin E2 and prostaglandin F2α responsiveness of endometrial scaffold constructs was tested using oxytocin plus arachidonic acid (OT + AA) or lipopolysaccharide (LPS). Stromal and epithelial cells growing on the electrospun scaffold had an architectural arrangement that mimicked whole tissue, deposited fibronectin, had appropriate expression of vimentin and cytokeratin and were responsive to OT + AA and LPS, as measured by prostaglandin accumulation. In conclusion, a functional 3D model of stromal and epithelial cells was developed using a PGA electrospun scaffold which may be used to study endometrial pathophysiology.

Investigation of anti-inflammatory, antinociceptive and antipyretic activities of Stahlianthus involucratus rhizome ethanol extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Stahlianthus involucratus (Zingiberaceae) has long been used in traditional medicine to treat inflammation, pain, and fever. However, no pharmacological study of this plant has been reported to confirm these activities. The aim of this study was to investigate the anti-inflammatory, antinociceptive and antipyretic activities of Stahlianthus involucratus rhizome ethanol extract (SiE) in animal models. MATERIALS AND METHODS: Anti-inflammatory activity of SiE was investigated in rats using ethyl phenylpropiolate (EPP)-induced ear edema, carrageenan- and arachidonic acid (AA)-induced hind paw edema, and cotton pellet-induced granuloma formation models. Acetic acid-induced writhing response in mice and tail-flick test in rats as well as yeast-induced hyperthermia in rats were used to investigate the antinociceptive and antipyretic activities, respectively. RESULTS: SiE significantly inhibited EPP-induced ear edema, carrageenan- and AA-induced hind paw edema. Its inhibitory effect in carrageenan-induced hind paw edema seemed to be in a dose-dependent manner. In cotton pellet-induced granuloma formation, SiE showed suppressive effects on granuloma formation but not on body weight gain and dry thymus weight. It could normalize serum alkaline phosphatase activity to nearly normal level. SiE also possessed a significant inhibitory effect, which seemed to be dose-dependent, on acetic acid-induced writhing response, whereas only at the highest dose of SiE could significantly increase test reaction time at all time-points in tail-flick test. However, no antipyretic activity was observed. CONCLUSIONS: These results suggest that SiE possesses anti-inflammatory and antinociceptive, but not antipyretic, activities. This study therefore rationalizes the traditional use of SiE for the treatment of inflammation and pain.

A subchronic toxicity study, preceded by an in utero exposure phase, with refined arachidonic acid-rich oil (RAO) derived from Mortierella alpina XM027 in rats.

To evaluate the potential toxicity of refined arachidonic acid-rich oil (RAO) derived from Mortierella alpina (M. alpina) XM027, we performed a 90-day subchronic study in F1 Sprague Dawley (SD) rats. This study was preceded by a 4-week pretreatment period of parental (F0) rats and exposure of the F0 dams throughout mating, gestation, and lactation. The results indicated that RAO, at dose levels of 0.5%, 1.5%, and 5%, did not affect either reproductive performance of the parental rats, or any characteristics of the pups. In the subchronic study with the offspring (F1) rats, no treatment related abnormalities were observed. In summary, no observable adverse effect level (NOAEL) in this study was placed at 5% RAO, the highest level tested. This level corresponds to approximately 3750mg/kg in F0 females, 2850mg/kg in F0 males, 4850mg/kg in F1 females, and 4480mg/kg in F1 males.

Antiplatelet and antithrombotic activities of non-steroidal anti-inflammatory drugs containing an N-acyl hydrazone subunit.

Nonsteroidal anti-inflammatory drugs (NSAIDs) 1-5 containing an N-acyl hydrazone subunit were prepared and their antiplatelet and antithrombotic activities assessed in vitro and in vivo. Compounds 1-5 inhibited the platelet aggregation induced by adenosine diphosphate and/or arachidonic acid, with inhibition rates of 18.0%-61.1% and 65.9%-87.3%, respectively. Compounds 1 and 5 were the most active compounds, inhibiting adenosine-diphosphate-induced platelet aggregation by 57.2% and 61.1%, respectively. The inhibitory rates for arachidonic-acid-induced platelet aggregation were similar for compound 2 (80.8%) and acetylsalicylic acid (ASA, 80%). After their oral administration to mice, compounds 1, 3, and 5 showed shorter mean bleeding times than ASA. Compounds 1 and 5 also protected against thromboembolic events, with survival rates of 40% and 33%, respectively, compared with 30% for ASA. In conclusion, these results indicate that these novel NSAIDs containing an NAH subunit may offer better antiplatelet and antithrombotic activities than ASA.

Prostaglandin E2-EP3 signaling induces inflammatory swelling by mast cell activation.

PGE2 has long been known as a potentiator of acute inflammation, but its mechanisms of action still remain to be defined. In this study, we employed inflammatory swelling induced in mice by arachidonate and PGE2 as models and dissected the role and mechanisms of action of each EP receptor at the molecular level. Arachidonate- or PGE2-induced vascular permeability was significantly reduced in EP3-deficient mice. Intriguingly, the PGE2-induced response was suppressed by histamine H1 antagonist treatment, histidine decarboxylase deficiency, and mast cell deficiency. The impaired PGE2-induced response in mast cell-deficient mice was rescued upon reconstitution with wild-type mast cells but not with EP3-deficient mast cells. Although the number of mast cells, protease activity, and histamine contents in ear tissues in EP3-deficient mice were comparable to those in wild-type mice, the histamine contents in ear tissues were attenuated upon PGE2 treatment in wild-type but not in EP3-deficient mice. Consistently, PGE2-EP3 signaling elicited histamine release in mouse peritoneal and bone marrow-derived mast cells, and it exerted degranulation and IL-6 production in a manner sensitive to pertussis toxin and a PI3K inhibitor and dependent on extracellular Ca(2+) ions. These results demonstrate that PGE2 triggers mast cell activation via an EP3-Gi/o-Ca(2+) influx/PI3K pathway, and this mechanism underlies PGE2-induced vascular permeability and consequent edema formation.

Novel surfactants with diglutamic acid polar head group: drug solubilization and toxicity studies.

PURPOSE: Novel surfactants made of diglutamic acid (DG) polar head linked to lithocholic, arachidonic, linoleic or stearic acids were designed for drug solubilization. METHODS: Surfactants 3-D conformer and packing parameter were determined by molecular modelling and self-assembling properties by pyrene fluorescence measurements. Cytotoxicity was assessed on Human Umbilical Vein Endothelial Cells (HUVEC) and haemolyitic activity on rat red blood cells. Drug solubilization was quantified and its interaction with hydrophobic moieties was characterized using differential scanning calorimetry and X-ray diffraction. Self organisation of stearoyl-DG was observed by cryogenic transmission electron microscopy. Toxicity after repeated injections of stearoyl-DG was investigated in Wistar rats. RESULTS: DG-based surfactants self-assemble into water and their critical micellar concentrations are comprised between 200 and 920 µg/mL. Cytotoxicity and haemolysis were lower than for polysorbate 80. At best, stearoyl-DG solubilized the drug up to 22% (w/w). Solid-state characterization evidenced drug/lipid interactions leading to the formation of a new complex. Stearoyl-DG formed spherical micelles of 20 nm, as predicted by packing parameter calculation. However, it induced a possible liver toxicity after intravenous administration in rats. CONCLUSIONS: Among the surfactants tested, stearoyl-DG is the more efficient for drug solubilization but its use is limited by its possible liver toxicity.

The stable cyclic adenosine monophosphate analogue, dibutyryl cyclo-adenosine monophosphate (bucladesine), is active in a model of acute skin inflammation.

Anti-inflammatory therapeutic options for the topical treatment of skin diseases with inflammatory or allergic contribution are mostly limited to topical glucocorticoids and calcineurin inhibitors. Both compound classes induce adverse effects. Elevation of intracellular cyclic adenosine monophosphate (cAMP) by inhibition of phosphodiesterase 4 was shown to induce potent anti-inflammatory effects, but the safety profile of currently available compounds is not sufficient. A different approach to increase intracellular cAMP is the substitution of chemically stabilized cAMP analogues. Bucladesine is a stabilized cAMP analogue with an excellent safety profile which had been marketed as topical treatment of impaired wound healing. In the current study, a novel water free emulsion containing bucladesine was evaluated for anti-inflammatory effects. In the arachidonic acid induced ear oedema model in mice, single or multiple administration of an emulsion containing 1.5% was capable of significantly reducing the inflammatory oedema. The data indicate that bucladesine represents an interesting treatment option for skin diseases where an anti-inflammatory activity is indicated. Due to the established clinical safety, this agent may bridge the gap between potent agents such as glucocorticoids or calcineurin inhibitors and emollients without active compounds.

Effectiveness of Vernonia scorpioides ethanolic extract against skin inflammatory processes.

ETHNOPHARMACOLOGICAL RELEVANCE: Vernonia scorpioides (Asteraceae) is a native Brazilian medicinal plant that is commonly used to treat skin disorders. Considering the traditional use of Vernonia scorpioides and the lack of information about its pharmacological properties, we investigated the topical anti-inflammatory effect of the ethanolic extract of Vernonia scorpioides (EEVS) on acute and chronic cutaneous inflammation models in mouse. MATERIALS AND METHODS: The topical anti-inflammatory effect of EEVS was evaluated against acute models (12-O-tetradecanoylphorbol acetate (TPA)- and arachidonic acid (AA)-induced mouse ear oedema) and chronic models (multiple applications of croton oil). RESULTS: The EEVS caused a dose-related inhibition of oedema in both the TPA- and AA-induced acute models (DI(50)=0.24 and 0.68 mg/ear with an inhibition of 80 ± 5% and 65 ± 5%, respectively, for 1mg/ear). In addition, the TPA-induced increase in myeloperoxidase activity (MPO) in the ear was reduced (77 ± 8%) by the topical application of EEVS. In the chronic model, the EEVS reduced all parameters evaluated: oedema formation (31 ± 2%), epidermal hyperproliferation (histology) and MPO (25 ± 10%). However, the topical treatment of EEVS had no effect on N-acetyl-ß-d-glucosaminidase activity. The EEVS effectively interfered in the ear oedema on the delayed-type hypersensitivity reaction induced by oxazolone. The topical treatment with EEVS performed on both phases or only on the elicitation phase caused the inhibition of the ear oedema-induced by oxazolone in 42.9% and 63.4%, respectively, when compared to control animals (sensitized and challenged). CONCLUSIONS: The results suggest that EEVS is effective as a topical anti-inflammatory agent in acute and chronic inflammatory processes and that its action is markedly influenced by the inhibition of neutrophil migration into inflamed tissue as well as by epidermal hyperproliferation.

Evaluation of bioequivalency and toxicological effects of three sources of arachidonic acid (ARA) in domestic piglets.

Arachidonic acid (ARA) and docosahexaenoic acid (DHA) are routinely added to infant formula to support growth and development. We evaluated the bioequivalence and safety of three ARA-rich oils for potential use in infant formula using the neonatal pig model. The primary outcome for bioequivalence was brain accretion of ARA and DHA. Days 3-22 of age, domestic pigs were fed one of three formulas, each containing ARA at ∼0.64% and DHA at ∼0.34% total fatty acids (FA). Control diet ARA was provided by ARASCO and all diets had DHA from DHASCO (Martek Biosciences Corp., Columbia, MD). The experimental diets a1 and a2 provided ARA from Refined Arachidonic acid-rich Oil (RAO; Cargill, Inc., Wuhan, China) and SUNTGA40S (Nissui, Nippon Suisan Kaisha, Ltd., Tokyo, Japan), respectively. Formula intake and growth were similar across all diets, and ARA was bioequivalent across treatments in the brain, retina, heart, liver and day 21 RBC. DHA levels in the brain, retina and heart were unaffected by diet. Liver sections, clinical chemistry, and hematological parameters were normal. We conclude that RAO and SUNTGA40S, when added to formula to supply ∼0.64% ARA are safe and nutritionally bioequivalent to ARASCO in domestic piglets.

Antioxidant, antinociceptive, and anti-inflammatory properties of the ethanolic extract of Combretum duarteanum in rodents.

The antioxidant, antinociceptive, and anti-inflammatory activities of the ethanolic extract from leaves of Combretum duarteanum (EEC) were assessed in rodents through in vitro tests. The antioxidant activity was investigated by using thiobarbituric acid reactive species (TBARS), hydroxyl radical-scavenging, and scavenging activity of nitric oxide assays. The antinociceptive activity was investigated by using acetic acid-induced writhing, formalin, and hot-plate tests in mice. The anti-inflammatory activity was assessed in rats by using the carrageenan-induced hind-paw edema test and arachidonic acid-induced paw edema test. EEC possesses a strong antioxidant potential according to the TBARS, nitric oxide, and hydroxyl radical-scavenging assays; it also presented scavenger activity in all in vitro tests. After intraperitoneal injection, EEC (100, 200, and 400 mg/kg) significantly reduced the number of writhes (38.1%, 90.6%, and 97.8%, respectively) in a writhing test and the number of paw licks during phase 1 (30.5% and 69.5%, higher doses) and phase 2 (38.1%, 90.6%, and 97.8%, all doses) of a formalin test when compared with the control group. Naloxone (1.5 mg/kg, intraperitoneally) antagonized the antinociceptive action of EEC (400 mg/kg), and this finding suggests participation of the opioid system. Administration of 200 and 400 mg/kg (intraperitoneally) of EEC exhibited an anti-inflammatory activity in the carrageenin test, which was based on interference with prostaglandin synthesis. This finding was confirmed by the arachidonic acid test. Together, these results indicate that properties of EEC might be further explored in the search for newer tools to treat painful inflammatory conditions, including those related to pro-oxidant states.

Anti-inflammatory activity of an alkaloid from Solanum trilobatum on acute and chronic inflammation models.

The solasodine isolated from Solanum trilobatum has been examined for possible anti-inflammatory activity in acute and chronic inflammatory animal models. Solasodine (5, 30 and 75 mg kg⁻¹) exerted statistically significant and dose-dependent anti-inflammatory activity in carrageenan-induced rat paw oedema, which was similar to that of indomethacin (10 mg kg⁻¹), a known anti-inflammatory agent. At the dose of 75 mg kg⁻¹, solasodine inhibited the arachidonic acid-elicited rat paw oedema 1 h after arachidonic acid challenge. Topical application of solasodine significantly inhibited the ear inflammation induced by multiple applications of tetradecanoyl-phorbol 13-acetate. It also suppressed the volume of exudates, total leucocytes and amount of neutrophil migration into the rat pleural cavity. Administration of solasodine at a dose of 75 mg kg⁻¹ significantly inhibited the adjuvant-induced rat paw oedema. These results suggest that solasodine exerts anti-inflammatory activity, at least partly through the inhibition of cyclooxygenase and 5-lipoxygenase pathways.

PUFAs enhance oxidative stress and apoptosis in tumour cells exposed to hypericin-mediated PDT.

Since many studies have suggested the impact of dietary polyunsaturated fatty acids on cancer progression and prognosis, there is an assumption of possible pre-sensitizing effects of their application in combined treatment. The present work evaluates modulation of photodynamic therapy (PDT) with hypericin by pre-treatment with n-3 and n-6 fatty acids in HT-29 and HeLa tumour cells. We observed stimulation of cytotoxic effects by docosahexaenoic acid (n-3) and arachidonic acid (n-6) in several stages of action in both cell lines. Treatment with either fatty acids or photodynamic therapy alone induced apoptosis in a dose- and time-dependent manner; however the effect was even more striking in mutual combination applied as pre-treatment with fatty acids prior to photodynamic therapy. Moreover, the combination also induced changes in membrane lipid composition leading to alteration in cell membrane fluidity. Increased toxicity of combined treatment was also confirmed by the presence of oxidative stress demonstrated by ROS production, RNS accumulation and increased presence of lipoperoxides. In conclusion, we suggest that pre-treatment with polyunsaturated fatty acids may contribute to cytotoxic effects induced by photodynamic therapy with hypericin.