Repeated oral administration of a squeezed ginger (Zingiber officinale) extract augmented the serum corticosterone level and had anti-inflammatory properties

We investigated the ability of a ginger extract to induce an immune response in RAW 264 cells and after a repeated oral administration to mice. The squeezed ginger extract augmented the production of tumor necrosis factor-α, interleukin-6, and monocyte chemotactic protein-1 when added to RAW 264 cells. This extract was collected as its ethanol-insoluble fraction. The oral administration of the squeezed ginger extract or its ethanol-insoluble fraction once or twice to mice also augmented the tumor necrosis factor-α production in peritoneal cells; however, its long-term administration had the opposite effect. The serum corticosterone level had increased after orally administering the squeezed ginger extract and was maintained during the administration period. Oral administration of the squeezed ginger extract also inhibited arachidonic acid-induced ear edema, but its repeated administration was needed to achieve an anti-inflammatory effect. These results suggest that the repeated administration of the aqueous constituents of ginger augmented the serum corticosterone level and that this may have gradually induced anti-inflammatory activity.     

Repeated Oral Administration of a Squeezed Ginger (Zingiber officinale) Extract Augmented the Serum Corticosterone Level and Had Anti-Inflammatory Properties

We investigated the ability of a ginger extract to induce an immune response in RAW 264 cells and after a repeated oral administration to mice. The squeezed ginger extract augmented the production of tumor necrosis factor-α, interleukin-6, and monocyte chemotactic protein-1 when added to RAW 264 cells. This extract was collected as its ethanol-insoluble fraction. The oral administration of the squeezed ginger extract or its ethanol-insoluble fraction once or twice to mice also augmented the tumor necrosis factor-α production in peritoneal cells; however, its long-term administration had the opposite effect. The serum corticosterone level had increased after orally administering the squeezed ginger extract and was maintained during the administration period. Oral administration of the squeezed ginger extract also inhibited arachidonic acid-induced ear edema, but its repeated administration was needed to achieve an anti-inflammatory effect. These results suggest that the repeated administration of the aqueous constituents of ginger augmented the serum corticosterone level and that this may have gradually induced anti-inflammatory activity.     

Studies on Enzymatic Synthesis of Oligosaccharides

The overproduction of tumor necrosis factor-α (TNF-α) was suppressed by orally administering a perilla leaf extract (PLE). When mice were successively injected with OK-432, severe TNF-α was induced in the serum, but this elevated TNF-α level was reduced after an oral administration of PLE (400 μl/mouse). Oral administration of PLE also inhibited TNF-α production that was induced by muramyl dipeptide (500 μg/mouse) and OK-432 (3 KE/mouse). These characteristics were obtained from all strains of perilla. The inhibitory activity against TNF-α production was heat-stable, and the existence of several active molecules was suggested. When PLE was passed through an ultrafilter, the inhibitory activity against TNF-α production was collected in those fractions with a mass of 0.5 to 1 kDa and more than 10 kDa. When PLE was solvent-extracted, the strongest activity was recognized with aqueous preparation, although significant activity was also detected in preparations extracted with n-hexane and ethyl acetate. These findings suggest that the daily use of certain functional foods may be useful for controlling the host defense system.     

Pharmacological assay of Cordia verbenacea V: oral and topical anti-inflammatory activity, analgesic effect and fetus toxicity of a crude leaf extract

Cordia verbenacea D.C. (Borraginaceae) is a perennial bush plant that grows widely along the southeastern coast of Brazil. Its leaves have been used in folk medicine for their anti-ulcer, anti-inflammatory and cicatrizing activities. We have already described the anti-inflammatory properties of C. verbenacea and its low toxicity in different acute animal models. In the present study, we investigated the anti-inflammatory activity in sub-chronic animal models of a crude leaf lyophilized extract when administered by oral route or topically applied, and concomitantly, its analgesic potency and toxicity to the fetus. Topical administration of the extract inhibited nystatin-induced edema proportionally to the doses used, and this effect at a dose of 4.56 mg/kg body wt. was similar to that observed with 6.0 mg/kg body wt. of naproxen. In miconazole-induced edema, the leaf extract at a dose of 1.24 mg/kg body wt., orally administered, has a very similar effect as compared to nimezulide (2.5 mg/kg body wt.) and dexamethasone (0.2 mg/kg body wt.). At an oral dose of 2.48 mg/kg body wt. the extract showed a very low analgesic effect, and total absence of fetus toxicity at doses of less than 7.44 mg/kg body wt.     

Anti-inflammatory activity of polysaccharide from <Emphasis Type="Italic">Pholiota nameko</Emphasis>

Pholiota nameko polysaccharide (PNPS-1) has been isolated and purified by enzymatic hydrolysis, hot water extraction, ethanol precipitation, and ion-exchange and gel-filtration chromatography. The anti-inflammatory activity of PNPS-1 was evaluated in rodents using xylene-induced ear edema, egg albumin-, carrageenin-, and formaldehyde-induced paw edema, cotton pellet granuloma test, adhesion of peritoneal leukocytes in vitro, and ulcerogenic activity. The results showed that PNPS-1 (5 mg/ear) inhibited topical edema in the mouse ear and at 100, 200, and 400 mg/kg (intraperitoneally) it significantly suppressed the development of egg albumin-, carrageenin-, and formaldehyde-induced paw edema in the animals. PNPS-1 (100, 200, and 400 mg/kg, per oral) significantly inhibited the growth of granuloma tissues induced by subcutaneously implanted cotton pellets in rats by 10.96, 18.07, and 43.75%, respectively. PNPS-1 also inhibited spontaneous and phorbol-12-myristate-13-acetate-activated adhesion of peritoneal leukocytes in vitro. Further, both acute as well as chronic administration of PNPS-1 (100, 200, and 400 mg/kg, per oral) did not produce any gastric lesion in rats. In conclusion, these data indicated that PNPS-1 possesses significant anti-inflammatory activity suggesting its potential as an anti-inflammatory agent for use in the treatment of various inflammatory-related diseases.     

Anti-inflammatory effect of the hydralcoholic extract of Zingiber officinale rhizomes on rat paw and skin edema.

Plant extracts have been used for centuries as a popular mode of treatment for several health disorders. Over the last ten years, the study of those extracts has attracted attention in different fields of the biological sciences. Ginger, the rhizome of Zingiber officinale Roscoe (Zingiberaceae), is a commom constituent of diet worldwide and it has been reported that its extracts present some pharmacological activities. Here we investigate the effects of the crude hydralcoholic extract of ginger rhizomes on the classical models of rat paw and skin edema. The carrageenan-, compound 48/80- or serotonin-induced rat paw edema were inhibited significantly by the intraperitoneal administration of alcoholic ginger extract. Ginger extract was also effective in inhibiting 48/80-induced rat skin edema at doses of 0.6 and 1.8 mg/site. Rat skin edema induced by substance P or bradikinin was not affected by treatment with Z. officinalle extract. The intraperitoneal administration of ginger extract (186 mg/kg(-1) body wt.) 1 h prior to serotonin injections, reduced significantly the serotonin-induced rat skin edema. Our results demonstrated that crude extract of Zingiber officinale was able to reduce rat paw and skin edema induced by carrageenan, 48/80 compound and serotonin. The antiedematogenic activity seems to be related, at least partially, to an antagonism of the serotonin receptor.     

Activity of taraxasteryl acetate on inflammation and heat shock protein synthesis

Pluchea sagittalis whole plant dichloromethane extract showed inhibitory activity in several inflammatory models: rat hind paw-edema, mice ear edema, and air-pouch rat granuloma. The extract inhibited the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in stimulated human neutrophils. It also showed inhibitory effect on heat shock protein 72 (hsp72) synthesis in stimulated neutrophils, while it had opposite effects on unstimulated cells. The triterpene taraxasteryl acetate was obtained from the dichloromethane extract by bioassay directed isolation, being active against induced ROS and RNS production in human neutrophils. In mice ear edema (induced by phorbol-12-mirystate-13-acetate, croton oil and arachidonic acid), taraxasteryl acetate showed a topical anti-inflammatory activity similar to the extract, but at 1/20 of the dose. The same ratio was observed for the inhibition of hsp72 production in stimulated human neutrophils. In unstimulated monocytes and neutrophils, taraxasteryl acetate showed a higher stimulating activity of hsp72 production than the extract, involving different mechanisms in each cell type. To our knowledge, taraxasteryl acetate is the first natural product for which a dual effect on the hsp response is reported.     

Sulfidopeptide-leukotrienes are major mediators of arachidonic acid-induced mouse ear edema

The inflammatory response of the mouse ear to topical application of arachidonic acid (2 mg/ear) was examined to study the roles of sulfidopeptide-leukotrienes (LTs) and prostaglandin (PG) E2 as mediators of edema. The increase in ear thickness caused by arachidonic acid (AA) (edema), reached a maximum at 45 to 60 min after AA application. The amounts of immunoreactive LTC4 and immunoreactive PGE2 produced increased significantly in 5 to 10 min, and then diminished gradually over 60 min. 5-lipoxygenase inhibitors, dual cyclooxygenase/lipoxygenase inhibitors and anti-histamines significantly inhibited AA-induced ear edema. Both production of PGE2 and LTC4 were suppressed by NDGA at 1 mg/ear which also inhibited ear swelling. However aspirin, which enhanced LTC4 production in AA-induced ear edema did not inhibit the ear swelling. Hypodermic injection of LTC4 at 25 ng or PGE2 at 500 ng/ear did not cause swelling, but edema was induced when both compounds were injected simultaneously. Moreover ear swelling was induced by injection of both LTD4 at 50 ng and PGE2 at 500 ng/ear. Furthermore, concomitant injection of histamine, at 500 ng or serotonin at 50 ng/ear with LTC4 at 25 ng caused ear swelling but both compounds at the same dose alone did not induce swelling. These results suggest that AA-induced ear edema is predominantly mediated by LTC4 and other lipoxygenase products while PGE2 (in the presence of LTs) acts to facilitated ear swelling, although serotonin and histamine may also contribute.     

Edema induced by Bothrops asper (Squamata: Viperidae) snake venom and its inhibition by Costa Rican plant extracts

We tested the capacity of leaf (Urera baccifera, Loasa speciosa, Urtica leptuphylla, Chaptalia nutans, and Satureja viminea) and root (Uncaria tomentosa) extracts to inhibit edema induced by Bothrops asper snake venom. Edema-forming activity was studied plethysmographically in the rat hind paw model. Groups of rats were injected intraperitoneally with various doses of each extract and, one hour later, venom was injected subcutaneously in the right hind paw. Edema was assessed at various time intervals. The edematogenic activity was inhibited in those animals that received an injection U. tomentosa, C. nutans or L. speciosa extract. The extract of U. baccifera showed a slight inhibition of the venom effect. Extract from S. viminea and, to a lesser extent that of U. leptuphylla, induced a pro-inflammatory effect, increasing the edema at doses of 250 mg/kg at one and two hours.     

Anti-inflammatory and antinociceptive potential of major phenolics from Verbascum salviifolium Boiss

The potential effects of flavonoids, phenylethanoid and neolignan glycosides from the aerial parts of Verbascum salviifolium Boiss. were studied in the p-benzoquinone-induced writhing reflex, for the assessment of the antinociceptive activity, and in carrageenan- and PGE1-induced hind paw edema and 12-O-tetradecanoyl-13-acetate (TPA)-induced ear edema models in mice, for the assessment of the anti-inflammatory activity. Through bioassay-guided fractionation and isolation procedures ten compounds from the aqueous extract of the plant, luteolin 7-O-glucoside (1), luteolin 3'-O-glucoside (2), apigenin 7-O-glucoside (3), chrysoeriol 7-O-glucoside (4), beta-hydroxyacteoside (5), martynoside (6), forsythoside B (7), angoroside A (8), dehydrodiconiferyl alcohol-9'-O-beta-D-glucopyranoside (9) and dehydrodiconiferyl alcohol-9-O-beta-D-glucopyranoside (10), were isolated and their structures were elucidated by spectral techniques. Results have shown that 1, 2, 3 and 5 significantly inhibited carrageenan-induced paw edema at a 200 mg/kg dose, while 1, 2 and 5 also displayed anti-inflammatory activity against the PGE1-induced hind paw edema model. However, all the compounds showed no effect in the TPA-induced ear edema model. The compounds 1 and 2 also exhibited significant antinociceptive activity.     

Study of the topical anti-inflammatory activity of Achillea ageratum on chronic and acute inflammation models

We have produced a chloroform extract from Achillea which includes stigmasterol and sitosterol. By comparing it with the pure compounds an anti-inflammatory effect (with mouse ears) is assumed. The topical anti-inflammatory effect of the chloroform extract from Achillea ageratum (Asteraceae) and of stigmasterol and beta-sitosterol, isolated of this extract has been evaluated, against to 12-0-tetradecanoylphorbol acetate (TPA)-induced mouse ear edema, using simple (acute model) and multiple applications (chronic model) of the phlogistic agent. Myeloperoxydase activity also was studied in the inflamed ears. In the acute model the extract exerted a dose-dependent effect. All the doses assayed (1, 3 and 5 mg/ear) significantly reduced the edema (50%, 66% and 82%, respectively). The isolated sterols stigmasterol and beta-sitosterol (with doses of 0.5 mg/ear) had similar effect as the extract with doses of 1 and 3 mg (59% and 65% respectively). In the chronic model the anti-inflammatory effect generally was a more moderate one. The highest dose of the extract decreased the edema reduction to 26% with the highest dose of the extract applied. With the compounds the effect decreased to 36% with stigmasterol, and 40.6% with beta-sitosterol. Myeloperoxydase activity (MPO) was reduced by the extract and the compounds in the acute model, however, in the chronic edema, the enzyme inhibition was very weak with all treatments even with the standard substance. These results indicate that the chloroform extract of Achillea ageratum and some of the its components stigmasterol and beta-sitosterol are more effective as topical anti-inflammatory agents in acute than in the chronic process and their action is markedly influenced by the inhibition of neutrophil migration into inflamed tissue.     

高粱、紫苏叶脉密度与光合特性的关系

叶脉是植物叶片光合作用水分输送的重要结构。为阐述叶脉与光合特性之间的关系,以C4植物高粱(Sorghum bicolor)、C3植物紫苏(Perilla frutescens)为实验材料研究了叶脉密度和光合特性之间的关系。结果表明,与紫苏相比,高粱叶片叶脉密度大,导水能力强,蒸腾速率高,但气孔密度小。进一步分析表明,高粱叶片近轴侧气孔密度占总气孔的比例明显高于紫苏。叶脉密度大的高粱具有较高的净光合速率;而紫苏叶脉密度小,净光合速率也较低。由此表明,较高的叶脉密度有利于支持较高的光合速率,但研究表明叶脉密度和气孔密度可能不存在严格的协同变异关系。研究结果对理解植物光合作用适应有重要意义。     

Anti-Inflammatory Activity of N-Butanol Extract from Ipomoea stolonifera In Vivo and In Vitro

Ipomoea stolonifera (I. stolonifera) has been used for the treatment of inflammatory diseases including rheumatism and rheumatoid arthritis in Chinese traditional medicine. However, the anti-inflammatory activity of I. stolonifera has not been elucidated. For this reason, the anti-inflammatory activity of n-butanol extract of I. stolonifera (BE-IS) was evaluated in vivo by using acute models (croton oil-induced mouse ear edema, carrageenan-induced rat paw edema, and carrageenan-induced rat pleurisy) and chronic models (cotton pellet-induced rat granuloma, and complete Freund’s adjuvant (CFA)-induced rat arthritis). Results indicated that oral administration of BE-IS significantly attenuated croton oil-induced ear edema, decreased carrageenan-induced paw edema, reduced carrageenan-induced exudates and cellular migration, inhibited cotton pellet-induced granuloma formation and improved CFA-induced arthritis. Preliminary mechanism studies demonstrated that BE-IS decreased the levels of myeloperoxidase (MPO) and malondialdehyde (MDA), increased the activity of anti-oxidant enzyme superoxide dismutase (SOD) in vivo, and reduced the production of nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in lipopolysaccharide-activated RAW264.7 macrophages in vitro. Results obtained in vivo and in vitro demonstrate that BE-IS has considerable anti-inflammatory potential, which provided experimental evidences for the traditional application of Ipomoea stolonifera in inflammatory diseases.     

Protective effects of a standard extract of Mangifera indica L. (VIMANG) against mouse ear edemas and its inhibition of eicosanoid production in J774 murine macrophages

A standard aqueous extract of Mangifera indica L., used in Cuba as antioxidant under the brand name VIMANG, was tested in vivo for its anti-inflammatory activity, using commonly accepted assays. The standard extract of M. indica, administered orally (50-200mg/kg body wt.), reduced ear edema induced by arachidonic acid (AA) and phorbol myristate acetate (PMA) in mice. In the PMA model, M. indica extract also reduced myeloperoxidase (MPO) activity. In vitro studies were performed using macrophage cell line J774 stimulated with pro-inflammatory stimuli lipopolysaccharide-interferon gamma (LPS-IFNgamma) or calcium ionophore A23187 to determine prostaglandin PGE(2) or leukotriene LTB(4) release, respectively. The extract inhibited the induction of PGE(2) and LTB(4) with IC(50) values of 21.7 and 26.0microg/ml, respectively. Mangiferin (a glucosylxanthone isolated from the extract) also inhibited these AA metabolites (PGE(2), IC(50) value=17.2microg/ml and LTB(4), IC(50) value=2.1microg/ml). These results represent an important contribution to the elucidation of the mechanism involved in the anti-inflammatory and anti-nociceptive effects reported for the standard extract of M. indica VIMANG.     

Antimicrobial activity of perilla seed polyphenols against oral pathogenic bacteria

A perilla seed (Perilla frutescens Britton var. japonica Hara) extract was examined for its antimicrobial activity against oral cariogenic streptococci and periodontopathic Porphyromonas gingivalis. Luteolin, one of the components of perilla seed, showed the strongest antimicrobial effect among the phenolic compounds. According to our results, perilla seed may be the source of an antimicrobial agent that could prevent dental caries and periodontal diseases.     

Isolation, identification, and biological evaluation of Nrf2-ARE activator from the leaves of green perilla (Perilla frutescens var. crispa f. viridis)

The nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway is a cellular defense system against oxidative stress. Activation of this pathway increases expression of antioxidant enzymes. Epidemiological studies have demonstrated that the consumption of fruits and vegetables is associated with reduced risk of contracting a variety of human diseases. The aim of this study is to find Nrf2-ARE activators in dietary fruits and vegetables. We first attempted to compare the potency of ARE activation in six fruit and six vegetables extracts. Green perilla (Perilla frutescens var. crispa f. viridis) extract exhibited high ARE activity. We isolated the active fraction from green perilla extract through bioactivity-guided fractionation. Based on nuclear magnetic resonance and mass spectrometric analysis, the active ingredient responsible for the ARE activity was identified as 2',3'-dihydroxy-4',6'-dimethoxychalcone (DDC). DDC induced the expression of antioxidant enzymes, such as γ-glutamylcysteine synthetase (γ-GCS), NAD(P)H: quinone oxidoreductase-1 (NQO1), and heme oxygenase-1. DDC inhibited the formation of intracellular reactive oxygen species and the cytotoxicity induced by 6-hydroxydopamine. Inhibition of the p38 mitogen-activated protein kinase pathway abolished ARE activation, the induction of γ-GCS and NQO1, and the cytoprotective effect brought about by DDC. Thus, this study demonstrated that DDC contained in green perilla enhanced cellular resistance to oxidative damage through activation of the Nrf2-ARE pathway.     

Oral administration of a hop water extract ameliorates the development of dermatitis induced by the periodical topical application of a mite antigen in atopic dermatitis model NC/Nga mice

We investigated the inhibitory effect of an oral administration of a hop water extract (HWE) on the development of dermatitis by using NC/Nga atopic dermatitis model mice. The induction of allergic dermatitis was conducted by tape-stripping and topical application of a mite antigen (Dermatophagoides farinae) on to the ear once a week for 10 weeks. HWE was orally administered at a dose of 100 or 500 mg/kg. The total immunoglobulin E (IgE) concentration in serum and the ear thickness were periodically examined. Finally, the antigen-specific IgE level in the serum and the production of interleukin (IL)-4, IL-12 and interferon (IFN)-gamma from splenocytes and cervical lymph node cells were measured. The oral administration of HWE significantly inhibited the increase of total IgE production and ear swelling throughout the experimental period. The production of IL-12 was significantly lower in the HWE administered group than in the control group. The results suggest that the intake of HWE may be effective in preventing and alleviating the development of atopic dermatitis-like skin disease.     

Anti-inflammatory and anti-allergic effect of rosmarinic acid (RA); inhibition of seasonal allergic rhinoconjunctivitis (SAR) and its mechanism

The present study was undertaken to determine whether oral supplementation with rosmarinic acid (RA) is an effective intervention for patients with SAR. In addition, the anti-inflammatory mechanism of RA also estimated in the ear edema models. CLINICAL TRIAL: Patients were treated daily with RA (200 mg or 50 mg) or placebo for 21 days. Patients recorded symptoms daily and profiles of infiltrating cells and concentration of cytokines were measured in nasal lavage fluid. Compared to placebo, supplementation with RA resulted in a significant decrease in responder rates for each symptom. RA also significantly decreased the numbers of neutrophils and eosinophils in nasal lavage fluid. ANIMAL STUDY: Topical application RA showed anti-inflammatory activity 5-hours after 12-tetradecanoylphorbol 13-acetate (TPA) treatment with marked inhibition of neutrophil infiltration. Up regulation of ICAM-1, VCAM-1 cyclooxygenase-2 (COX-2), KC and MIP-2 by TPA were markedly reduced by pre-treatment with extract of perilla (PE) or RA. Reactive oxygen radical production detected as thiobarbituric acid reactive substance (TBARS), lipid peroxide (LPO) and 8-hydroxy-2'deoxyguanosine (8OH-dG), by double treatment of TPA was reduced by pretreatment with PE or RA. RA is an effective intervention for SAR that is mediated by inhibition of PMNL infiltration. This effect of RA is due to two independent mechanisms: inhibition of the inflammatory response and scavenging of ROS.     

In vitro and in vivo anti-allergic effects of Arctium lappa L

The discovery of drugs that can be used for the treatment of allergic disease is important in human health. Arctium lappa Linne (Compositae) (AL) has been used as a traditional medicine in Brazil and throughout Asia and is known to have an anti-inflammatory effect. In this study, the inhibitory effects of AL on degranulation and the release of mediators as well as on inhibition of cys-leukotriene biosynthesis by basophils were investigated. AL was selected out of 10,000 herbal extracts in a set-up for high throughput screening in which the degree of degranulation was monitored by the release of beta-hexosaminidase from rat basophil leukemia (RBL-2H3) cells. The AL extract significantly reduced degranulation and biosynthesis of cys-leukotrienes of human basophils in peripheral blood mono-nuclear cells (PBMCs) (50% inhibitory concentration [IC(50)] = 8.3 and 11.4 microg/ml, respectively). Viability and metabolic activity of the PBMCs were not affected. Although arctiin, the active component of AL that has been described in the literature, was not able to reduce degranulation in RBL-2H3 cells, a single high-performance liquid chromatography (HPLC) fraction from the AL extract inhibited beta-hexosaminidase release (IC(50) = 22.2 microg/ml). Topical administration of an aqueous extract of AL (5 mg/ear) on the ear of whey-sensitized mice 4 hrs before challenge with whey in the ear inhibited acute ear swelling by 50% in an in vivo cow's milk allergic model. The extract had no effect in this model when administered orally. In conclusion, the active component present in the active HPLC fraction of the AL extract was able to significantly reduce the release of inflammatory mediators through inhibition of degranulation and cys-leukotriene release in vitro. In addition, this active component was able to inhibit acute skin response in mice in vivo, indicating that AL is a very promising natural component for use in anti-allergic treatment.     

Immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) against chromium (VI) induced immunosuppression

The present study reports the immunomodulatory effects of seabuckthorn (Hippophae rhamnoides L.) leaf extract on cellular and humoral immune response by studying delayed-type hypersensitivity response, IL-2, IL-4 and γ-IFN levels and antibody titres in chromium-induced immunosuppressed animals. Oral feeding of chromium (30 mg/kg bw) significantly inhibited antibody production and S-RBC induced delayed-type hypersensitivity response. Administration of leaf extract (100 mg/kg bw) along with chromium significantly inhibited chromium-induced immunosuppression. To understand the immunomodulatory mechanism of leaf extract, in vitro studies were carried out using rat lymphocytes. Addition of chromium resulted in a significant decrease in lymphocyte size and increased ROS generation. The leaf extract of seabuckthorn significantly inhibited chromium-induced reactive oxygen species (ROS) generation and maintained the cell size identical to that of control cells. Chromium treatment markedly inhibited the mitochondrial transmembrane potential by larger lymphocytes in particular, while the leaf extract restored the same significantly. Chromium also inhibited significantly concanavalin A (ConA) induced IL-2, IL-4 and γ-IFN production in rat lymphocytes. The leaf extract (100 μg/ml) alone stimulated IL-2 and γ-IFN production even in the absence of ConA and also inhibited chromium-induced decline in IL-2 and γ-IFN production but it did not change IL-4 production. These observations suggest that the leaf extract of seabuckthorn has significant immunomodulatory activity and specifically activates the cell-mediated immune response. (Mol Cell Biochem 278: 101–109, 2005)