Daily Inhalation of α‐Pinene in Mice: Effects on Behavior and Organ Accumulation

In phytotherapy, essential oils tend to be used daily for a period of days or weeks, rather than in a single application. However, the literature contains very little information on repeated use of essential oils. In this study, we investigated the effects on behavior and the accumulation in the brain and liver of α‐pinene, an essential oil component, when inhaled by mice. Animals were individually housed in cages for 1 week. Mice inhaled α‐pinene or water vapor (negative control) for 90 min/day for 1 day, 3 days, or 5 days, and they were then submitted to the elevated plus maze test for 10 min. We used gas chromatography with flame ionization detection to quantify concentrations of α‐pinene in the brain and liver. There was significant anxiolytic‐like activity, which remained constant for the 5 days' inhalation of α‐pinene. On the other hand, the accumulation of α‐pinene in the brain and liver peaked on the third day of inhalation. The existence of stress related to the new environment appears to have affected the change in the accumulation of α‐pinene in the internal organs, keeping the anxiolytic‐like action constant. Copyright © 2013 John Wiley & Sons, Ltd.     

Expression of BDNF and TH mRNA in the Brain Following Inhaled Administration of α‐Pinene

Essential oils are mainly administered by inhalation. Administration by inhalation is considered to occur through two pathways, neurological transfer and pharmacological transfer. However, the relationship between the two routes is not clear. To clarify this relationship, we administered α‐pinene, which has an anxiolytic‐like effect, to mice. Emotional behavior and accumulation and expression of relevant mRNAs in the brain (brain‐derived neurotrophic factor (BDNF); tyrosine hydroxylase (TH)) were examined following inhaled administration of α‐pinene (10 μL/L air for 60 or 90 min). To evaluate the anxiolytic‐like effect, the elevated plus maze (EPM) test was used. Inhalation of α‐pinene for 60 min produced a significant increase in the total distance traveled in the EPM test compared with control (water). The concentration of α‐pinene in the brain after 60 min of inhalation was significantly increased compared with that after 90 min of inhalation. The expression of BDNF mRNA in the olfactory bulb and in the hippocampus was almost the same after 60 min of inhalation compared to that after 90 min of inhalation. The expression of TH mRNA in the midbrain after 60 min of inhalation was significantly increased compared with that of the control. Thus, an increase in α‐pinene in the brain induces an increase in TH mRNA expression and increases locomotor activity. The anxiolytic‐like effect may be related to both neurological transfer and pharmacological transfer. Copyright © 2014 John Wiley & Sons, Ltd.     

Composition and antimicrobial activity of the essential oil of Hypericum rumeliacum subsp. apollinis (Boiss. & Heldr.)

The composition and the antimicrobial activity of the aerial parts of Hypericum rumeliacum are reported. Analysis was carried out by GC/MS. The major constituents were alpha-pinene (43.80%), beta-pinene (9.82%), dehydro-aromadendrene (6.81%) and alpha-copaene (5.41%). The essential oil showed a moderate in vitro activity against the six Gram negative and positive bacteria and a stronger one against the three-tested pathogenic activity.     

Anti‐Inflammatory,Antinociceptive and Cytotoxic Effects of the Methanol Extract of Cecropia pachystachya Trécul

Cecropia pachystachya is widely used in the traditional medicine as anti‐inflammatory, antitusive, expectorant, antiasthmatic and hypoglycemic. It is also commercially available to treat skin cancer. To validate some of the popular uses of this species, its methanol leaves extract (CPM) was tested for anti‐inflammatory, antinociceptive and cytotoxic effects. The anti‐inflammatory activity was evaluated by croton oil‐induced ear edema test. When used orally, the anti‐inflammatory effect of CPM at 300 mg/kg was similar to that of indomethacin with 53% inhibition of the ear edema. Also, results on topical treatment were similar to that of dexamethasone with 83% inhibition of the edema. To evaluate the antinociceptive activity, acetic acid‐induced writhing and formalin‐induced pain tests were employed. CPM (100 and 300 mg/kg) reduced the number of writhing by 61% and 67%, respectively. In both doses, the activity was comparable to the reference drug, indomethacin. The oral administration of CPM was ineffective in the first phase of formalin test but exhibited great effects on the second phase decreasing the licking time by 85% at 300 mg/kg. The cytotoxic potential of CPM was also investigated against HL60, HL60.bcl2 and Jurkat tumor cell lines and showed an inhibition of more than 50% of cell proliferation. The flavones orientin and isoorientin were detected in CPM. Copyright © 2012 John Wiley & Sons, Ltd.     

Antiinflammatory effects of ginger and some of its components in human bronchial epithelial (BEAS-2B) cells

The proinflammatory chemokine interleukin‐8 is increased in asthmatic patients. Traditionally, ginger is used as an antiinflammatory drug. An extract and several compounds of Zingiber officinale (ginger) were tested in human bronchial epithelial cells (BEAS‐2B cells) with respect to their effect on lipopolysaccharide (LPS)‐induced secretion of the proinflammatory chemokine interleukin 8 (IL‐8) and RANTES (regulated upon activation, normal T‐cell expressed and secreted). An oily extract of ginger rhizome with > 25% total pungent compounds, ginger volatile oil, ar‐curcumene and α‐pinene reduced the LPS‐induced IL‐8 secretion (measured by a specific enzyme‐linked immunosorbent assay), whereas a spissum extract, the pungents [6]‐gingerol and its metabolite [6]‐shogaol, and the terpenoids citral and β‐phellandrene showed no effect. The LPS‐induced slight increase of RANTES was reduced by volatile oil, ar‐curcumene and α‐pinene. There was no effect of LPS on TNF‐α. Our results suggest that distinct ginger compounds could be used as antiinflammatory drugs in respiratory infections. Copyright © 2011 John Wiley & Sons, Ltd.     

Comparative study on the antiviral activity of selected monoterpenes derived from essential oils

Essential oils are complex natural mixtures, their main constituents, e.g. terpenes and phenylpropanoids, being responsible for their biological properties. Essential oils from eucalyptus, tea tree and thyme and their major monoterpene compounds α‐terpinene, γ‐terpinene, α‐pinene, p‐cymene, terpinen‐4‐ol, α‐terpineol, thymol, citral and 1,8‐cineole were examined for their antiviral activity against herpes simplex virus type 1 (HSV‐1) in vitro. These essential oils were able to reduce viral infectivity by >96%, the monoterpenes inhibited HSV by about >80%. The mode of antiviral action has been determined, only moderate antiviral effects were revealed by essential oils and monoterpenes when these drugs were added to host cells prior to infection or after entry of HSV into cells. However, both essential oils and monoterpenes exhibited high anti‐HSV‐1 activity by direct inactivation of free virus particles. All tested drugs interacted in a dose‐dependent manner with herpesvirus particles thereby inactivating viral infection. Among the analysed compounds, monoterpene hydrocarbons were slightly superior to monoterpene alcohols in their antiviral activity, α‐pinene and α‐terpineol revealed the highest selectivity index. However, mixtures of different monoterpenes present in natural tea tree essential oil revealed a ten‐fold higher selectivity index and a lower toxicity than its isolated single monoterpenes. Copyright © 2009 John Wiley & Sons, Ltd.     

Identification of a new antinociceptive alkaloid isopropyl N-methylanthranilate from the essential oil of Choisya ternata Kunth

Ethnopharmacological relevance

Mexican people employed infusion of leaves of Choisya ternata Kunth for their antispasmodic and “simulative properties”.

Aim of the study

In the present study the detailed GC and GC-MS analyses of the essential oil of Choisya ternata Kunth (Rutaceae) were performed. The presence of a minor constituent isopropyl N-methylanthranilate (1) was revealed among other identified volatiles. A synthesis of 1 was undertaken in order to corroborate this find and obtain gram quantities that would allow the testing of its biological activity (peripheral and central antinociceptive activity).

Materials and methods

The oils were investigated by GC and GC-MS. Synthesized compounds were spectrally characterized (UV-Vis, IR, 1D and 2D NMR, MS). The obtained synthetic samples of compounds were assayed for peripheral and central antinociceptive activity in two models (effects on acetic acid induced writhing in mice and the hot plate test for nociception).

Results

Detailed GC and GC-MS analyses of the essential oil of Choisya ternata Kunth (Rutaceae) among 157 other identified volatiles revealed the presence of a minor constituent isopropyl N-methylanthranilate (1). Compound 1, named ternanthranin, is therefore detected as a natural product for the first time with a very restricted occurrence (samples of several citrus oils were screened for the presence of 1). The antinociceptive activities were assayed for ternanthranin, the two other synthetic analogs, methyl and propyl N-methylanthranilate, as well as the essential oil and the crude ethanol extract of the leaves. The results clearly demonstrate a very high (even significant at 0.3 mg/kg) dose dependent activity for the anthranilates (and the extracts). Isopropyl N-methylanthranilate showed the highest, while methyl N-methylanthranilate showed the lowest activity (with the methyl ester at 3 mg/kg still better than acetylsalicylic acid, at 200 mg/kg, in the first, or comparable with morphine, at 5 mg/kg, in the second test).

Conclusion

This study once again revealed that detailed investigations of plant species with ethnopharmacologically documented activity may yield new natural compounds—a new alkaloid (ternanthranin), a volatile simple anthranilate that can be considered responsible for the antinociceptive activity of the crude plant extracts.     

Investigations on the antinociceptive effect of Psidium guajava leaf essential oil and its major constituents

The antinociceptive effect of leaf essential oil from Psidium guajava and its major constituents, β-caryophyllene and α-pinene was assessed using chemical (formalin and acetic acid) and thermal (hot-plate) nociceptive tests in adult male albino mice. Oral administration of 100, 200 and 400 mg/kg of essential oil produced a significant antinociceptive effect in the formalin test and at 200 and 400 mg/kg in the acetic acid- induced writhing test. Of the major components only α-pinene, but not the β-caryophyllene, demonstrated significant antinociception in the formalin test. Neither the essential oil nor the major components could exert any significant effect in the hot-plate test. Pretreatment of mice with caffeine (20 mg/kg, i.p.), significantly inhibited the antinociceptive effect of essential oil in the formalin test. Naloxone (1 mg/kg, s.c.), the opioid antagonist, however, failed to antagonize it. These results suggest that the antinociceptive effect of P. guajava essential oil is probably mediated by endogenously released adenosine. © 1998 John Wiley & Sons, Ltd.     

Multiple Biological Effects of Olive Oil By‐products such as Leaves,Stems, Flowers,Olive Milled Waste,Fruit Pulp,and Seeds of the Olive Plant on Skin

As olive oil production increases, so does the amount of olive oil by‐products, which can cause environmental problems. Thus, new ways to utilize the by‐products are needed. In the present study, five bioactive characteristics of olive oil by‐products were assessed, namely their antioxidant, anti‐bacterial, anti‐melanogenesis, anti‐allergic, and collagen‐production‐promoting activities. First, the extracts of leaves (May and October), stems (May and October), flowers, olive milled waste, fruit pulp and seeds were prepared using two safe solvents, ethanol and water. According to HPLC and LC/MS analysis and Folin–Ciocalteu assay, the ethanol extracts of the leaves (May and October), stems (May and October) and flowers contained oleuropein, and the ethanol extract of the stems showed the highest total phenol content. Oleuropein may contribute to the antioxidant and anti‐melanogenesis activities of the leaves, stems, and flowers. However, other active compounds or synergistic effects present in the ethanol extracts are also likely to contribute to the anti‐bacterial activity of the leaves and flowers, the anti‐melanogenesis activity of some parts, the anti‐allergic activity of olive milled waste, and the collagen‐production‐promoting activity of the leaves, stems, olive milled waste and fruit pulp. This study provides evidence that the by‐products of olive oil have the potential to be further developed and used in the skin care industry. Copyright © 2015 John Wiley & Sons, Ltd.     

Organ Accumulation in Mice After Inhalation of Single or Mixed Essential Oil Compounds

Essential oils are composed of multiple components. It is thought that the effect of essential oils is due to specific component ratios, which may differ from the original ratio when the essential oil is absorbed. However, very little detailed research exists in this area. We studied the distribution of essential oil components after inhalation of single and mixed components in mice. This research was done using four main components of Alpinia zerumbet (Pers.) B. L. Burtt. and R. M. Sm.: α‐pinene, p‐cymene, 1,8‐cineole, and limonene. After inhalation of single or mixed components for 90 min, component levels in the brain and liver of mice were measured. The results indicated that the amount of α‐pinene in the brain and liver was twofold greater after mixed‐component inhalation than that after single‐component inhalation. In a comparison of the components of the mixed inhalation, the ratio of α‐pinene increased to about three times that of 1,8‐cineole. It is thought that the absorption via the nasal mucus greatly influences this phenomenon. The results of this investigation of the bodily distribution of essential oil volatile components may provide clues for elucidating their action. Copyright © 2012 John Wiley & Sons, Ltd.     

HS-SPME-GC-MS和主成分分析红车轴草不同部位挥发油成分

目的:分析红车轴草不同部位挥发油成分差异。方法:采用顶空固相微萃取法萃取红车轴草挥发油成分,结合气相色谱质谱联用法分析其组成,面积归一化法计算各成分的相对含量,主成分分析挥发油成分。结果:红车轴草茎、叶和花共鉴定出155种化合物,包括烃类55种、醇类29种、酮类23种、酯类13种、醛类21种、酸类2种、酚类3种、杂环及其他类化合物9种。茎鉴定出95种化合物,占挥发性成分的94.15%,主要含有35种烃类(39.14%),18种醇类(10.86%),16种酮类(19.61%),6种酯类(4.06%),11种醛类(7.48%);叶鉴定出89种化合物,占挥发性成分的95.17%,主要含有37种烃类(41.58%),16种醇类(14.88%),12种酮类(18.18%),3种酯类(9.27%),14种醛类(4.69%);花鉴定出78种化合物,占挥发性成分的91.66%,主要含有28种烃类(45.24%),12种醇类(4.81%),10种酮类(11.57%),8种酯类(6.65%),11种醛类(9.24%)。茎、叶和花3个样品获得的挥发油成分总峰面积分别为0.56×109,1.14×109,0.55×109,叶中挥发油具有最大的峰面积。3个部位样品中共有成分为41种,但茎、叶和花含有特有成分分别为29,41,14种。2个主成分可代表3个样品的155种挥发油成分,样品之间的主成分分析综合评分具有较大差异,叶样品的综合评分最高。结论:红车轴草茎、叶和花挥发油成分种类和含量存在较大的差异。     

Antinociceptive and antiinflammatory activities of grandisin extracted from Virola surinamensis

The antinociceptive and antiinflammatory properties of the neolignan, grandisin, isolated from Virola surinamensis (Myristicaceae) were investigated. Grandisin (GRA) is present in several plant species from Brazil used in popular medicine for the treatment of disorders such as colic, inflammation, rheumatism, dyspepsia and liver dysfunction. These studies demonstrated that GRA is able to inhibit the acetic acid‐induced writhing in mice dose‐dependently, and that this effect is not caused by motor incoordination or sedation due to depressant effect in the CNS. Through the formalin test the antiinflammatory activity of GRA was characterized, this substance reduced the time licking the paw by 60.5% (only in the second phase (inflammatory pain). This activity was also verified by the oil‐induced ear oedema test, where GRA 10.0 mg/kg reduced the oedema by 36.4%. The results suggest that GRA has antinociceptive effects arising from antiinflammatory activity. Copyright © 2009 John Wiley & Sons, Ltd.     

山东产忍冬不同药用部位挥发油成分分析及抗氧化活性

目的:对山东产忍冬花、茎、叶不同药用部位进行挥发性成分分析及抗氧化活性研究。方法:分别提取忍冬花、茎、叶的挥发油,利用GC-MS进行成分分析和比较;用70%乙醇分别提取忍冬花、茎、叶,提取液回收溶剂后分别用石油醚、乙酸乙酯、正丁醇萃取,利用DPPH比色法对各萃取物、萃取后的水相部位及挥发油分别进行体外抗氧化能力比较。结果:从忍冬花、茎、叶中共分离鉴定了49种成分,三者共有成分11种,分别占各自挥发油含量的60.66%,77.98%和80.38%,含量最高的均为棕榈酸。忍冬花、茎、叶的不同提取物对DPPH自由基均有较好的清除作用,且清除能力随着浓度的增加而增加,但各样品间存在一定差异。乙酸乙酯萃取物清除能力最强,依次是正丁醇萃取物、水相、挥发油、石油醚萃取物;花的清除能力最强,茎和叶次之。结论:忍冬花、茎、叶中挥发油成分具有较高相似性;三者挥发油及不同极性提取物均具有较好的抗氧化能力。     

Composition and antibacterial activity of Abies balsamea essential oil

The antibacterial activity of the essential oil of Abies balsamea (balsam fir) was evaluated against Escherichia coli and Staphylococcus aureus. The essential oil of A. balsamea was found to be inactive against E. coli (>100 microg/mL) and active against S. aureus, with an MIC of 56 microg/mL. The oil composition was analysed by GC-MS and the antibacterial activity of each oil constituent was determined. The essential oil of A. balsamea is essentially constituted of monoterpenes (>96%) and some sesquiterpenes. beta-pinene (29.9%), delta-3-carene (19.6%) and alpha-pinene (14.6%) were the major components. beta-pinene and delta-3-carene were found inactive against both bacteria strains. However, three constituents of the essential oil were active against S. aureus: alpha-pinene, beta-caryophyllene (0.4%) and alpha-humulene (0.2%) with MIC values of 13.6 microg/mL, 5.1 microg/mL and 2.6 microg/mL, respectively.     

Plants of the Melaleuca Genus as Antimicrobial Agents: From Farm to Pharmacy

Plants belonging to Melaleuca genus (Myrtaceae family) are native to Oceania, where they have been used for ages by Aborigine people in Australian traditional medicine, mainly because of their broad‐spectrum antimicrobial activity. Although, M. linariifolia, M. dissitiflora, and other species of Melaleuca can also be used, the tea tree oil, an essential oil obtained from M. alternifolia shows the longest history of medicinal uses. Tea tree oil contains for the 80–90% several monoterpenes (terpinen‐4‐ol, α‐terpinene, 1,8‐cineol, p‐cymene, α‐terpineol, α‐pinene, terpinolene, limonene, and sabinene). Sesquiterpenes and aromatic compounds further compose this oil. The essential oil of Melaleuca spp. has been reported to possess effective antibacterial and antifungal properties in vitro. In particular, data show that 1,8‐cineol, terpinen‐4‐ol and methyl eugenol play the key role in mediating this oil's antimicrobial activity. Copyright © 2017 John Wiley & Sons, Ltd.     

Upregulation of PPARγ by Aegle marmelos ameliorates insulin resistance and β-cell dysfunction in high fat diet fed-streptozotocin induced type 2 diabetic rats

The global epidemic of type 2 diabetes demands the rapid evaluation of new and accessible interventions. This study investigated whether Aegle marmelos fruit aqueous extract (AMF; 250, 500 and 1000 mg/kg) improves insulin resistance, dyslipidemia and β‐cell dysfunction in high fat diet fed‐streptozotocin (HFD‐STZ)‐induced diabetic rats by modulating peroxisome proliferator‐activated receptor‐γ (PPARγ) expression. The serum levels of glucose, insulin, homeostasis model assessment of insulin resistance (HOMA‐IR), homeostasis model assessment of β‐cell function (HOMA‐B), lipid profile, TNF‐α and IL‐6 were evaluated. Further, the TBARS level and SOD activity in pancreatic tissue and PPARγ protein expression in liver were assessed. In addition, histopathological and ultrastructural studies were performed to validate the effect of AMF on β‐cells. The HFD‐STZ treated rats showed a significant increase in the serum levels of glucose, insulin, HOMA‐IR, TNF‐α, IL‐6, dyslipidemia with a concomitant decrease in HOMA‐B and PPARγ expression. Treatment with AMF for 21 days in diabetic rats positively modulated the altered parameters in a dose‐dependent manner. Furthermore, AMF prevented inflammatory changes and β‐cell damage along with a reduction in mitochondrial and endoplasmic reticulum swelling. These findings suggest that the protective effect of AMF in type 2 diabetic rats is due to the preservation of β‐cell function and insulin‐sensitivity through increased PPARγ expression. Copyright © 2011 John Wiley & Sons, Ltd.     

Orofacial antinociceptive effect and antioxidant properties of the hydroethanol extract of Hyptis fruticosa salmz ex Benth

Ethnopharmacological relevance

Hyptis fruticosa is a plant native to Brazil with antinociceptive and antiinflamatory properties. This study evaluated the antinociceptive activity of the hydroethanol extract of the plant leaves (CHEE) against orofacial pain as well as its in vitro effect against lipid peroxidation.

Materials and methods

The antinociceptive activity was investigated in mice orally treated with different doses of the CHEE (50, 100, and 200 mg/kg) and morphine (5 mg/kg) using formalin, glutamate, and capsaicin orofacial pain models using. Lipoperoxidation was induced in egg yolk by AAPH and FeSO₄ in the absence and presence of the CHEE (5, 50, 100, and 150 μg/mL).

Results

CHEE (200 mg/kg) significantly reduced (ρ<0.001) the pain response in the first (69.6%) and second (81.8%) phases of the formalin test, while the nociception caused by capsaicin was significantly (ρ<0.001) reduced by up to 62% at 200 mg/kg of extract. When glutamate was used as algogen, a significant (ρ<0.001) nociception reduction of up to 85% at 200 mg/kg extract was observed. CHEE showed a higher protection against lipoperoxidation caused by FeSO₄ (82.3% TBARS inhibition) than AAPH (35.7% TBARS inhibition) at 150 μg/mL.

Conclusion

Hyptis fruticosa leaf CHEE is of pharmacological interest because it was able to inhibit the peripheral and central transmission of orofacial pain, while reducing the spreading of the inflammatory processes by neutralizing reactive oxygen species, which are by-products in the biosynthesis of pain mediators.     

Essential Oil of Juniperus communis subsp. alpina (Suter) Čelak Needles: Chemical Composition,Antifungal Activity and Cytotoxicity

Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria and fungi. In the present work the composition and the antifungal activity of the oils of Juniperus communis subsp. alpina (Suter) ?elak were evaluated. Moreover, the skin cytotoxicity, at concentrations showing significant antifungal activity, was also evaluated. The oils were isolated by hydrodistillation and analysed by gas chromatography and gas chromatography–mass spectrometry. Minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oil against dermatophytes (Epidermophyton floccosum, Microsporum canis, M. gypseum, Trichophyton mentagrophytes, T. mentagrophytes var. interdigitale, T. rubrum, T. verrucosum), yeasts (Candida albicans, C. guillermondii, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans) and Aspergillus species (Aspergillus flavus, A. fumigatus, A. niger). Cytotoxicity was tested in HaCaT keratinocytes through the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. Essential oil of J. communis subsp. alpina needles was predominantly composed of monoterpene hydrocarbons (78.4%), with the main compounds being sabinene (26.2%), α‐pinene (12–9%) and limonene (10.4%). Results concerning the antifungal activity demonstrated the potential of needle oil against dermatophytes, particularly for Microsporum canis and Trichophyton rubrum with MIC and MLC of 0.32 μL/mL. Furthermore, evaluation of cell viability showed no significant cytotoxicity in HaCaT keratinocytes at concentrations between 0.32 and 0.64 μL/mL. These results show that it is possible to find appropriate doses of J. communis subsp. alpina oil with both antifungal activity and a very low detrimental effect on keratinocytes. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of insulin and its combination with resveratrol or curcumin in attenuation of diabetic neuropathic pain: participation of nitric oxide and TNF-alpha

Diabetic neuropathic pain, an important microvascular complication in diabetes mellitus, is recognized as one of the most difficult types of pain to treat. The underlying mechanisms of painful symptoms may be closely associated with hyperglycaemia but a lack of the understanding of its proper aetiology, inadequate relief, development of tolerance and potential toxicity of classical antinociceptives warrant the investigation of newer agents to relieve this pain. The aim of the present study was to explore the antinociceptive effect of insulin and its combinations with resveratrol and curcumin in attenuating diabetic neuropathic pain. The study also aimed to examine the effect of these combinations on tumour necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) levels in streptozotocin (STZ) induced diabetic mice. Four weeks after a single intraperitoneal injection of streptozotocin (200 mg/kg), mice were tested in the tail immersion and hot-plate assays. Diabetic mice exhibited significant hyperalgesia along with increased plasma glucose and decreased body weights compared with control mice. Chronic treatment with insulin (10 IU/kg/day, s.c.) and its combinations with antioxidants (resveratrol 20 mg/kg or curcumin 60 mg/kg, p.o.) for 4 weeks starting from the 4th week of STZ injection significantly attenuated thermal hyperalgesia and the hot-plate latencies. There was a significant inhibition of TNF-alpha and NO levels when these drugs were given in combination compared with their effects per se. These results indicate an antinociceptive activity of resveratrol and curcumin and point towards the beneficial effect of these combinations with insulin in attenuating diabetic neuropathic pain, possibly through the participation of NO and TNF-alpha.