Attenuation of capsaicin-induced acute and visceral nociceptive pain by alpha- and beta-amyrin, a triterpene mixture isolated from Protium heptaphyllum resin in mice

Ethnobotanical knowledge and utilization patterns of Burseraceae resins in Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Amid all the Brazilian phytodiversity, in all its shades and shapes, black and white amorphous masses glued to the barks of Burseraceae species stand out as some of the nation's most appreciated plant medicinal resources. Burseraceae resins have been used in all macroregions of Brazil, wherever they occur, for a variety of medicinal purposes. However, despite ongoing interest in them, their cultural and health relevance in the country has been underexamined.

AIM OF THE STUDY

This review aimed to illuminate the therapeutic importance and potential of Brazilian Burseraceae by assembling the ethnomedicinal, chemical, and pharmacological data available on its resins used in Brazil.

MATERIALS AND METHODS

A search for journal articles documenting local ethnomedicinal uses of Burseraceae resins and reporting chemical and pharmacological data associated with their botanical sources was conducted in ScienceDirect, Google Scholar, and PubMed databases. Books and theses were also appraised for such information.

RESULTS

At least 21 Burseraceae taxa, belonging to Protium, Trattinnickia, and Commiphora, are recorded as sources of medicinal resins in Brazil. Protium and Trattinickia yield oleoresins typically rich in mono- and triterpenoids, especially the pentacyclic triterpenoids α- and β-amyrin. Although Commiphora oleo-gum-resins are expected to differ significantly from Protium and Trattinickia oleoresins by the presence of gum fractions, they often exhibit distinct terpenoid compositional patterns, characterized by a high proportion of sesquiterpenoids and tetracyclic triterpenoids. Burseraceae resins are more frequently cited in the Brazilian ethnomedicinal literature for relieving headaches and healing wounds. Pharmacological evidence corroborates the potential of Burseraceae resins against these and some other conditions and diseases, however, further studies are needed to confirm their efficacy and safety when used topically and through inhalation-the two primary routes of administration explored for them in Brazil.

CONCLUSIONS

The present review unearths a consistent, persistent, and cross-cultural pattern of using Burseraceae resins against pain conditions. But to really tap into the Burseraceae's therapeutic potential in Brazil, we first need to address the following gaps: (a) conduct more thorough pharmacological studies, including clinical trials; (b) give more attention to the triterpenoid fraction of Burseraceae oleoresins, not only to essential oils and α- and β-amyrin; and (c) deepen our understanding of the impact of resin aging on chemical composition.

Evidence for the efficacy of anti-inflammatory plants used in Brazilian traditional medicine with ethnopharmacological relevance

ETHNOPHARMACOLOGICAL RELEVANCE

When exacerbated, inflammatory processes can culminate in physical and emotional disorders and, if not stopped, can be lethal. The high prevalence of inflammation has become a public health problem, and the need for new drugs to treat this pathology is imminent. The use of medicinal plants has emerged as an alternative, and a survey of data that corroborates its application in inflammatory diseases is the starting point. Furthermore, Brazil harbors a megadiversity, and the traditional use of plants is relevant and needs to be preserved and carefully explored for the discovery of new medicines.

AIM OF THE STUDY

This review sought to survey the medicinal plants traditionally used in Brazil for the treatment of inflammatory processes and to perform, in an integrative way, a data survey of these species and analysis of their phytochemical, pharmacological, and molecular approaches.

MATERIALS AND METHODS

Brazilian plants that are traditionally used for inflammation (ophthalmia, throat inflammation, orchitis, urinary tract inflammation, ear inflammation, and inflammation in general) are listed in the DATAPLAMT database. This database contains information on approximately 3400 native plants used by Brazilians, which were registered in specific documents produced until 1950. These inflammatory disorders were searched in scientific databases (PubMed/Medline, Scopus, Web of Science, Lilacs, Scielo, Virtual Health Library), with standardization of DECS/MESH descriptors for inflammation in English, Spanish, French, and Portuguese, without chronological limitations. For the inclusion criteria, all articles had to be of the evaluated plant species, without association of synthesized substances, and full articles free available in any of the four languages searched. Duplicated articles and those that were not freely available were excluded.

RESULTS

A total of 126 species were identified, culminating in 6181 articles in the search. After evaluation of the inclusion criteria, 172 articles representing 40 different species and 38 families were included in the study. Comparison of reproducibility in intra-species results became difficult because of the large number of extraction solvents tested and the wide diversity of evaluation models used. Although the number of in vitro and in vivo evaluations was high, only one clinical study was found (Abrus precatorius). In the phytochemical analyses, more than 225 compounds, mostly phenolic compounds, were identified.

CONCLUSION

This review allowed the grouping of preclinical and clinical studies of several Brazilian species traditionally used for the treatment of many types of inflammation, corroborating new searches for their pharmacological properties as a way to aid public health. Furthermore, the large number of plants that have not yet been studied has encouraged new research to revive traditional knowledge.

Bioactive Triterpenes of Protium heptaphyllum Gum Resin Extract Display Cholesterol-Lowering Potential

Hypercholesterolemia is one of the major causes of cardiovascular disease, the risk of which is further increased if other forms of dyslipidemia occur. Current therapeutic strategies include changes in lifestyle coupled with drug administration. Statins represent the most common therapeutic approach, but they may be insufficient due to the onset of resistance mechanisms and side effects. Consequently, patients with mild hypercholesterolemia prefer the use of food supplements since these are perceived to be safer. Here, we investigate the phytochemical profile and cholesterol-lowering potential of Protium heptaphyllum gum resin extract (PHE). Chemical characterization via HPLC-APCI-HRMS² and GC-FID/MS identified 13 compounds mainly belonging to ursane, oleanane, and tirucallane groups. Studies on human hepatocytes have revealed how PHE is able to reduce cholesterol production and regulate the expression of proteins involved in its metabolism. (HMGCR, PCSK9, LDLR, FXR, IDOL, and PPAR). Moreover, measuring the inhibitory activity of PHE against HMGR, moderate inhibition was recorded. Finally, molecular docking studies identified acidic tetra- and pentacyclic triterpenoids as the main compounds responsible for this action. In conclusion, our study demonstrates how PHE may be a useful alternative to contrast hypercholesterolemia, highlighting its potential as a sustainable multitarget natural extract for the nutraceutical industry that is rapidly gaining acceptance as a source of health-promoting compounds.

Antinociceptive effect of triterpene acetyl aleuritolic acid isolated from Croton zehntneri in adult zebrafish (Danio rerio)

Croton zehntneri is a plant known as canelinha de cunhã, prevalent in the northeast region of Brazil. Many constituents of the vegetable have already been studied, and their pharmacological properties have been proven, but this is the first study to analyze the antinociceptive effect in adult zebrafish (ZFa) of the triterpene acetyl aleuritolic acid (AAA) isolated from the stem bark. The animals (ZFa; n = 6/group) were treated intraperitoneally (ip; 20 μL) with AAA (0.1 or 0.3 or 1.0 mg/mL) or vehicle (0.9% saline; 20 μL), and submitted to the locomotor activity test, as well as 96 h acute toxicity. Other groups (n = 6/each) received the same treatments and underwent acute nociception tests (formalin, cinnamaldehyde, glutamate, acid saline, capsaicin, and hypertonic saline). Possible neuromodulation mechanisms were evaluated. AAA (0.1 or 0.3 or 1.0 mg/mL) reduced the nociceptive behavior induced by acid saline and capsaicin, as well as inhibited corneal nociception induced by hypertonic saline, both without altering the animals' locomotor system and without toxicity. These analgesic effects of AAA were significantly (p > 0.05) similar to those of morphine, used as a positive control. The antinociceptive effect of AAA was inhibited by methylene blue, ketamine, camphor, ruthenium red, amiloride, and mefenamic acid. The antinociceptive effect of AAA on the cornea of animals was inhibited by capsazepine. Therefore, AAA showed pharmacological potential for the treatment of acute pain, and this effect is modulated by cGMP, NMDA receptors, transient receptor potential channels (TRPs), ASICs and has pharmacological potential for the treatment of corneal pain modulated by the TRPV1 channel.

Health benefits of 4,4-dimethyl phytosterols: an exploration beyond 4-desmethyl phytosterols

4,4-Dimethyl phytosterols possess two methyl groups at the carbon-4 atom of the aliphatic A-ring. The methyl groups are crucial for the molecular recognition of endogenous and exogenous bioactive compounds. Phytosterols have received worldwide attention owing to their recognized health benefits. However, 4,4-dimethyl phytosterols are less appreciated. Recent research studies revealed that 4,4-dimethyl phytosterols exert numerous beneficial effects on disease prevention, and are particularly involved in the endogenous cannabinoid system (ECS). The purpose of this review is to summarize and highlight the currently available information regarding the structures and sources of 4,4-dimethyl phytosterols, and to provide detailed preclinical studies performed to evaluate their potential for treating various diseases. Future research on 4,4-dimethyl phytosterols is warranted to confirm their relationship with the ECS, and to elucidate the mechanism directly toward clinical trials.

Structural elucidation and in vivo anti-arthritic activity of β-amyrin and polpunonic acid isolated from the root bark of Ziziphus abyssinica HochstEx. A Rich (Rhamnaceae)

Two natural products, compounds 1 and 2 were isolated from the root bark of Ziziphus abyssinica for the first time and were structurally elucidated as β-amyrin and polpunonic acid, respectively. Both compounds were further subjected to an in vivo study in rats to evaluate their anti-arthritic potency. Compared to the arthritic control group, rats treated with different doses of 1 or 2 (3, 10, and 30 mg/kg) exhibited significantly higher total change in body weight as well as lower arthritic scores and total change in paw edema and erythema. Histopathological examinations of the hind paws of the rats further demonstrated the beneficial effects of both compounds as they significantly reversed cartilage erosion, subchondral cyst, and Weichselbaum's lacunae formation. Evidence of bone remodeling was also observed in all groups of rats treated with 1 or 2. Hematological and serum biochemical parameters were not significantly affected by treatment of 1 or 2. Taken together, the results from the present study suggest potential therapeutic benefit of β-amyrin and polpunonic acid in rheumatoid arthritis and related inflammatory disorders.

Pharmacological effects of the isomeric mixture of alpha and beta amyrin from Protium heptaphyllum: a literature review

Protium heptaphyllum Aubl. belongs to the Burseraceae family. It is commonly called 'almecegueira' and is known to produce an amorphous resin which has constituents such as α- and β-amyrin, taraxastan-3-oxo-20-ol and sitostenonein. The α- and β-amyrin from P. heptaphyllum have pharmacological activities in several systems, such as central and peripheral nervous system, gastrointestinal tract and immunological system. In this study, our objective was to review pharmacological activities and to gather more information on the mixture of α- and β-amyrin obtained from P. heptaphyllum to guide future preclinical and clinical studies using this compound. This review consisted of searches performed using scientific databases such as PubMed, SciELO, LILACS, SciFinder and Science Direct. Some uses of α- and β-amyrin have been partially confirmed by previous studies demonstrating analgesic, anti-inflammatory, anticonvulsant, antidepressive, gastroprotective, hepatoprotective, antipancreatitic, anticholytic, antihyperglycemic and hypolipidemic effects. It is noteworthy that there are no α- and β-amirin toxicity tests described in the literature as recommended in the international guidelines, and such tests are one of the research stages to proceed in clinical and preclinical trials if this compound was to be used.

Analgesic-Like Activity of Essential Oil Constituents: An Update

The constituents of essential oils are widely found in foods and aromatic plants giving characteristic odor and flavor. However, pharmacological studies evidence its therapeutic potential for the treatment of several diseases and promising use as compounds with analgesic-like action. Considering that pain affects a significant part of the world population and the need for the development of new analgesics, this review reports on the current studies of essential oils’ chemical constituents with analgesic-like activity, including a description of their mechanisms of action and chemical aspects.

Culture-Bound Syndromes of a Brazilian Amazon Riverine population: Tentative correspondence between traditional and conventional medicine terms and possible ethnopharmacological implications

ETHNOPHARMACOLOGICAL RELEVANCE

It is not always possible to correlate the "emic" terms to the "etic" ones during ethnopharmacological surveys, especially regarding those related to Culture-Bound Syndromes (CBS). Nevertheless, it is the role of ethnopharmacology to address these correlations, since they are the basis for the understanding of potential bioactives.

AIM AND OBJECTIVES

This study reports the clinical manifestations and therapeutic resources used for the treatment of CBS among some riverine inhabitants of Brazilian Amazonia. An effort was made to establish a correspondence between the local "emic" terms of traditional medicine and the symptoms or diseases known by conventional medicine ("etic" terms). The ultimate goal was to gain insights to suggest further pharmacological studies with the local resources.

MATERIAL AND METHODS

Fieldwork was guided by methods of anthropology, botany and zoology-with the assistance of a doctor-among the traditional healing experts in Jaú National Park (during 199 days in 1995) and Unini River Extractive Reserve (210 days from 2008 to 2012).

RESULTS

Fifty-nine healers of different kinds were interviewed: a prayer-maker, medium, natural resource expert, massage therapist, midwife and snakebite healer. The clinical manifestations and healing resources of the following CBS were collected: "mau olhado" (evil eye), "quebrante" (chipping); "espante" (fright or susto); "doença do ar" (air diseases); "vento caído" (fallen wind); "derrame" (leakage); "mãe do corpo" (mother of the body) and "panema" (unlucky). The first three seem to be local variations of other CBSs already described in Latin America. "doença do ar", "vento caído", "derrame" and "mãe do corpo" seem to be folk terms for known conventional medical disorders, while "panema" is a yet undescribed Brazilian CBS that is possibly related to dysthymic disorder or depression and deserves further investigation. Treatments included prayer rituals, fumigation, baths and oral remedies using 25 plants and 10 animals.

CONCLUSION

It was possible to establish hypothetical correlations between CBS as described by the riverine population studied and some "etic" terms. The main importance of this is to help the proposition of target-oriented pharmacological studies of the natural resources used by these communities. Accordingly, the following plants are suggested to be submitted to further studies for antidepressant and anxiolytic activities: Siparuna guianensis, Mansoa alliacea, Leucas martinicensis, Petiveria alliacea, Annona montana and Alpinia nutans; for anti-seizure activity: Protium amazonicum, Protium aracouchini and Protium heptaphyllum; finally for antispasmodic activity: Leucas martinicensis.

Ficus hispida Bark Extract Prevents Nociception, Inflammation, and CNS Stimulation in Experimental Animal Model

Background. Ficus hispida is traditionally used in the ailment of pain, inflammation, and neurological disorders. The present study set out to evaluate the in vivo antinociceptive, anti-inflammatory, and sedative activity of the ethanol extract of Ficus hispida bark (EFHB). Methods. The antinociceptive activity of EFHB was evaluated by using acetic acid induced writhing, formalin, hot plate, and tail immersion methods in Swiss albino mice. Its anti-inflammatory activity was assessed by using carrageenan and histamine induced rat paw oedema test in Wister rats. The central stimulating activity was studied by using pentobarbital induced hypnosis, hole cross, and open field tests in Swiss albino mice. Results. EFHB demonstrated antinociceptive activity both centrally and peripherally. It showed 62.24% of writhing inhibition. It significantly inhibited licking responses in early (59.29%) and late phase (71.61%). It increased the reaction time to the thermal stimulus in both hot plate and tail immersion. It inhibited the inflammation to the extent of 59.49%. A substantial increase in duration of sleep up to 60.80 min and decrease of locomotion up to 21.70 at 400 mg/kg were also observed. Conclusion. We found significant dose dependent antinociceptive, anti-inflammatory, and sedative properties of EFHB in experimental animal models.

Strong and Long-Lasting Antinociceptive and Anti-inflammatory Conjugate of Naturally Occurring Oleanolic Acid and Aspirin

The conjugate 8 was obtained as a result of condensation of 3-hydroxyiminooleanolic acid morfolide (7) and aspirin in dioxane. Analgesic effect of OAO-ASA (8) for the range of doses 0.3–300.0 mg/kg (p.o.) was performed in mice using a hot-plate test. Anti-inflammatory activity was assessed on carrageenan-induced paw edema in rats for the same range of doses. The conjugate OAO-ASA (8) did not significantly change locomotor activity of mice, therefore sedative properties of the compound should be excluded. The compound 8 proved a simple, proportional, dose-dependent analgesic action and expressed strong anti-inflammatory activity showing a reversed U-shaped, dose-dependent relation with its maximum at 30.0 mg/kg. After its combined administration with morphine (MF, 5.0 mg/kg, s.c.) the lowering of antinociceptive activity was found; however, the interaction with naloxone (NL, 3.0 mg/kg, s.c.) did not affect the antinociceptive effect of OAO-ASA (8), therefore its opioid mechanism of action should be rather excluded. After combined administration with acetylsalicylic acid (ASA, 300.0 mg/kg, p.o.) in hot-plate test, the examined compound 8 enhanced the antinociceptive activity in significant way. It also shows that rather the whole molecule is responsible for the antinociceptive and anti-inflammatory effect of the tested compound 8, however, it cannot be excluded that the summarizing effect is produced by ASA released from the compound 8 and the rest of triterpene derivative. The occurrence of tolerance for triterpenic derivative 8 was not observed, since the analgesic and anti-inflammatory effects after chronic administration of the conjugate OAO-ASA (8) was on the same level as after its single treatment. It seemed that the anti-inflammatory mechanism of action of OAO-ASA (8) is not simple, even its chronic administration lowered both blood concentration of IL-6 and mRNA IL-6 expression. However, the effects of the conjugate OAO-ASA (8) on TNF-α level and mRNA expression were opposite. Moreover, compound 8 did not change unequivocally mRNA TLR1, and TLR3 expression. Concluding, the obtained results regarding the antinociceptive and anti-inflammatory activity of new conjugate of oleanolic acid oxime and acetylsalicylic acid (OAO-ASA 8) are very interesting, but for explanation of its mechanism of action, more detailed studies are necessary.

Essential Oil from the Resin of Protium heptaphyllum: Chemical Composition, Cytotoxicity, Antimicrobial Activity, and Antimutagenicity

Background:

Protium heptaphyllum (Aubl.) March is popularly used as an analgesic and anti-inflammatory agent.

Objective:

This study aimed to evaluate the chemical composition of P. heptaphyllum essential oil, its cytotoxicity in a breast cancer cell line (MCF-7), antimicrobial activity, and its antimutagenicity in vivo.

Materials and Methods:

The chemical composition of the essential oil collected in three 3 years was determined by gas chromatography-mass spectrometry. The cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Annexin V conjugated with fluorescein isothiocyanate, caspase-3, and tumor necrosis factor-alpha (TNF-α) assays were performed to evaluate apoptosis and inflammatory events. The antimutagenic activity at doses of 25, 50, and 100 mg/kg was determined using a micronucleus test in murine bone marrow.

Results:

The essential oil showed a predominance of monoterpene compounds, being the terpinolene, p-cymene-8-ol, and p-cymene, present in the essential oil extracted in the 3 years. The essential oil showed a protection against cyclophosphamide-induced genotoxicity, and the cytotoxicity index polychromatic erythrocytes/normochromatic erythrocytes ratio in animals treated with oil at all doses (1.34 ± 0.33; 1.15 ± 0.1; 1.11 ± 0.13) did not differ from the negative control animal (1.31 ± 0.33), but from the cyclophosphamide group (0.61 ± 0.12). Cytotoxicity, at a concentration of 40.0 μg/mL, and antimicrobial activity were not observed for the essential oil (minimum inhibitory concentration ≥0.5 mg/mL). The essential oil did not change the levels of caspase-3 in the TNF-α level.

Conclusion:

The essential oil showed antimutagenic activity due to its chemical composition.

SUMMARY

Terpinolene, p-cymene-8-ol, and p-cymene are the main constituents of the essential oil of P. heptaphyllum collected within 3-years

The essential oil of P. heptaphyllum did not show antimicrobial activity (MIC >0.5 mg/mL) against E. coli, S. aureus, E. faecalis, and C. albicans

The essential oil of P. heptaphyllum has activity against S. mutans (MIC = 0.5 mg/mL)

The essential oil showed a protection against cyclophosphamide-induced genotoxicity in the micronuclei assay.

Abbreviations used: GC–MS: Gas Chromatography–Mass Spectrometry, MTT: 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Annexin V-FITC: Annexin V conjugated with fluorescein isothiocyanate, TNF-α: Tumor necrosis factor alpha, MIC: Minimum Inhibitory Concentration

Evaluation of p-cymene, a natural antioxidant

CONTEXT

Several studies have demonstrated that essential oils and their major components have antioxidant activity. p-Cymene is a monoterpene and a major constituent of essential oils of various species of plants.

OBJECTIVE

This paper evaluated the antioxidant potential of p-cymene in the hippocampus of mice by determining the levels of thiobarbituric acid reactive substances (TBARS), nitrite content, and activity of catalase (CAT) and superoxide dismutase (SOD).

MATERIALS AND METHODS

Swiss mice were intraperitoneally treated with 0.05% Tween 80 dissolved in 0.9% saline solution, ascorbic acid 250 mg/kg, and p-cymene at doses of 50, 100, and 150 mg/kg, respectively. After treatment, all groups were observed for 24 h, afterwards, the groups were euthanized for removal of the brain and dissection of the hippocampus.

RESULTS

The results of treatment with p-cymene were a significant decrease in lipid peroxidation and nitrite content at a dose of CYM 50: 65.54%, CYM 100: 73.29%, CYM 150: 89.83%, and CYM 50: 71.21%; CYM 100: 68.61% and CYM 150:67%, respectively, when compared with the control group. The results showed that at all tested doses, p-cymene produces an increase in SOD and catalase activity significantly at a dose of CYM 50: 22.7%, CYM 100: 33.9%, CYM 150: 63.1%, and CYM 50: 119.25%, CYM 100: 151.83% and CYM 150: 182.70%, respectively, when compared with the vehicle-treated group.

DISCUSSION AND CONCLUSION

The result of this study shows that p-cymene has an antioxidant potential in vivo and may act as a neuroprotective agent in the brain. This compound may present a new strategy in the development of treatment for many diseases in which oxidative stress plays an important pathophysiological role.

The Resin from Protium heptaphyllum Prevents High-Fat Diet-Induced Obesity in Mice: Scientific Evidence and Potential Mechanisms

Herbal compounds rich in triterpenes are well known to regulate glucose and lipid metabolism and to have beneficial effects on metabolic disorders. The present study investigated the antiobesity properties of resin from Protium heptaphyllum (RPH) and the possible mechanisms in mice fed a high-fat diet (HFD) for 15 weeks. Mice treated with RPH showed decreases in body weight, net energy intake, abdominal fat accumulation, plasma glucose, amylase, lipase, triglycerides, and total cholesterol relative to their respective controls, which were RPH unfed. Additionally, RPH treatment, while significantly elevating the plasma level of ghrelin hormone, decreased the levels of insulin, leptin, and resistin. Besides, HFD-induced increases in plasma levels of proinflammatory mediators TNF-α, IL-6, and MCP-1 were significantly lowered by RPH. Furthermore, in vitro studies revealed that RPH could significantly inhibit the lipid accumulation in 3T3-L1 adipocytes (measured by Oil-Red O staining) at concentrations up to 50 μg/mL. These findings suggest that the antiobese potential of RPH is largely due to its modulatory effects on various hormonal and enzymatic secretions related to fat and carbohydrate metabolism and to the regulation of obesity-associated inflammation.

Ethnopharmacological Significance of Eclipta alba (L.) Hassk. (Asteraceae)

Eclipta alba can be found growing wild in fallow lands of Bangladesh where it is considered as a weed by farmers. Traditional medicinal systems of the Indian subcontinent countries as well as tribal practitioners consider the plant to have diverse medicinal values and use it commonly for treatment of gastrointestinal disorders, respiratory tract disorders (including asthma), fever, hair loss and graying of hair, liver disorders (including jaundice), skin disorders, spleen enlargement, and cuts and wounds. The plant has several phytoconstituents like wedelolactone, eclalbasaponins, ursolic acid, oleanolic acid, luteolin, and apigenin. Pharmacological activities of plant extracts and individual phytoconstituents have revealed anticancer, hepatoprotective, snake venom neutralizing, anti-inflammatory, and antimicrobial properties. Phytoconstituents like wedelolactone and ursolic and oleanolic acids as well as luteolin and apigenin can form the basis of new drugs against cancer, arthritis, gastrointestinal disorders, skin diseases, and liver disorders.

Recent advances in synthesis and biological activity of triterpenic acylated oximes

During the last few decades more and more attention has been paid to triterpenes-a group of compounds with five- or four-ring skeleton and carboxyl, hydroxyl or oxo groups. Triterpenes with unsubstituted C-3 hydroxyl group can be easily transformed into appropriate ketones and then into oximes. The carbonyl group can be created not only from the hydroxyl group at C-3 position, but also at C-2, C-12 or C-28 positions. Several methods of creation of two = NOH groups within one molecule of triterpene are known. There are also known triterpenes with two carbonyl groups, e.g. at C-3 and C-11 positions, which differ in reactivity: among them only C-3 group can be transformed into oxime. A reactive hydroxyimine group can undergo the action of acylating agents, such as carboxylic acids or their derivatives, also the ones with significant pharmacological activity. Acyl derivatives of triterpenic oximes exhibit important pharmacological activity. The biological tests performed with the use of cell cultures inoculated with viruses showed inhibitory activity of some triterpenic acyloximes against type 1 HSV (H7N1), ECHO-6 and HIV-1 viruses. Another acylated oximes derived from triterpenes shown cytotoxic or antiproliferative activity against many lines of cancer cells. In many cases the pharmacological effects of the tested acyloxyiminotriterpenes were comparable to those of appropriate standard drugs. One of the newest application of acyl derivatives of triterpenic oximes is their ability to form organogels.

Chemodiversity of ursane- and oleanane-type triterpenes in Amazonian Burseraceae oleoresins

The oleoresins exuded from species of the Burseraceae family present high potential due to their biological and pharmacological properties. The evaluation of the chemodiversity of the oleoresins of 23 Amazonian species of Burseraceae provided a profile of the principal constituents, viz., the ursane-type triterpenes α-amyrin (1), α-amyrenone (3), and brein (5) and the oleanane-type triterpenes β-amyrin (2), β-amyrenone (4), and maniladiol (6), and allowed to determine which of these species have the highest biotechnological potential and which ones are rich in other, potentially new, triterpenes or volatile compounds of interest for the cosmetics industry. The oleoresin compositions obtained by GC-FID and GC/MS analyses were submitted to principal component analysis (PCA) and hierarchical clustering on principal components (HCPC), which divided the 23 samples in five clusters. Protium giganteum and Trattinnickia peruviana, constituting the first cluster, presented high oleoresin contents of 3 and 4 (28.8 and 16.3% on average, resp.). The seven species of Burseraceae composing the second cluster were potential producers of new triterpenes and volatile compounds. Dacryodes hopkinsii and five Protium species (third cluster) presented average contents for all the triterpenes analyzed. The highest contents of 5 and 6 (averages of 3.9 and 5.4%, resp.) were observed in P. heptaphyllum ssp. ullei and T. glaziovii (fourth cluster). Finally, the six Protium species forming the fifth cluster showed high contents of 1 and 2 (48.0 and 19.9% on average, resp.). Moreover, this study allowed the description of the triterpene composition of 13 not previously investigated species.

Phytochemical Analysis and Antimicrobial, Antinociceptive, and Anti-Inflammatory Activities of Two Chemotypes of Pimenta pseudocaryophyllus (Myrtaceae)

Preparations from Pimenta pseudocaryophyllus (Gomes) L.R. Landrum (Myrtaceae) have been widely used in Brazilian folk medicine. This study aims to evaluate the antimicrobial activity of the crude ethanol extracts, fractions, semipurified substances, and essential oils obtained from leaves of two chemotypes of P. pseudocaryophyllus and to perform the antinociceptive and anti-inflammatory screening. The ethanol extracts were purified by column chromatography and main compounds were spectrally characterised (1D and 2D ¹H and ¹³C NMR). The essential oils constituents were identified by GC/MS. The broth microdilution method was used for testing the antimicrobial activity. The abdominal contortions induced by acetic acid and the ear oedema induced by croton oil were used for screening of antinociceptive and anti-inflammatory activities, respectively. The phytochemical analysis resulted in the isolation of pentacyclic triterpenes, flavonoids, and phenol acids. The oleanolic acid showed the best profile of antibacterial activity for Gram-positive bacteria (31.2–125 μg mL⁻¹), followed by the essential oil of the citral chemotype (62.5–250 μg mL⁻¹). Among the semipurified substances, Ppm5, which contained gallic acid, was the most active for Candida spp. (31.2 μg mL⁻¹) and Cryptococcus spp. (3.9–15.6 μg mL⁻¹). The crude ethanol extract and fractions from citral chemotype showed antinociceptive and anti-inflammatory effects.

The analgesic and anti-inflammatory effect of new oleanolic acid acyloxyimino derivative

The new derivative of well-known triterpene, oleanolic acid: methyl 3-octanoyloxyiminoolean-12-en-28-oate 5, was synthesized by the action of caprylic acid on methyl oleanolate 3-oxime in the presence of dicyclohexylcarbodiimide in dioxane. The molecular structure of the obtained product 5 was confirmed by spectral methods. The acute toxicity, locomotor activity, and the dose-dependent analgesic activity were studied. In addition, the effect of compound 5 on morphine-induced analgesic activity, the dose-dependent anti-inflammatory activity and the effect of the compound on diclofenac anti-inflammatory activity study were performed. The results proved a low toxicity (LD₅₀ > 2 g/kg) of the tested product 5, which affected neither vertical nor horizontal locomotor activity in the given range of doses. The triterpene 5 also produced centrally mediated (morphine-like) analgesic action; however, only in the highest dose. The synergistic analgesic activity of 5 and morphine in the doses of 30.0 and 300.0mg/kg was found. Compound 5 expressed the anti-inflammatory action which did not affect the anti-inflammatory activity of diclofenac after their combined administration.

p-Cymene protects mice against lipopolysaccharide-induced acute lung injury by inhibiting inflammatory cell activation

The objective of this study was to test the hypothesis that p-cymene can attenuate acute lung injury induced by lipopolysaccharide (LPS) in vivo. In the mouse model of LPS-induced acute lung injury, intraperitoneal preconditioning with p-cymene resulted in a significant reduction of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), lung water gain, inflammatory cell infiltration, lung tissue myeloperoxidase activity. In addition, p-cymene blocked the phosphorylation of IκBα protein and mitogen-activated protein kinases (MAPK) signaling pathway activation. Histopathologic examination of lung tissue indicated that p-cymene treatment markedly decreased focal thickening, congestion, pulmonary edema, and inflammatory cells infiltration. The results showed that p-cymene had a protective effect on LPS-induced ALI in mice.

Black cohosh: coming full circle?

ETHNOPHARMACOLOGICAL RELEVANCE

Black cohosh (Actaea racemosa L.), Ranunculaceae, thrives in temperate climates east of the Mississippi River in the USA. It is economically important to the Appalachian region where it is wild harvested, but it has resisted most efforts at deliberate cultivation. Black cohosh has been used for many centuries both in Europe and in the US (by indigenous people and subsequent Caucasian medical practitioners), most notably for indications of premenstrual syndrome (PMS), menstrual pain and cramping.

AIM OF THE STUDY

To highlight black cohosh as an example in which disregard for the ethnobotanical and ethnopharmacologic usages of a plant has perhaps hindered modern scientific attempts to understand the mechanism of action of its bioactive phytochemicals, and ascribe cause to effect.

RESULTS

Research on its mode of action has historically focused on its presumed hormonal (phytoestrogenic) activity, but very recent work suggests that it may in fact be acting as an antinociceptive agent. Re-examination of some of the writings of 19th and 20th century physicians and folk literature suggests that this mode of action may have been overlooked in modern experimentalists' in vitro and animal studies and in the very few well conducted human trials to date.

CONCLUSIONS

The common folk perception of this plant as a "remedy for female problems" may thus require revision, as it may possess more general analgesic properties. In the broader context, ethnopharmacologic indications for other herbal remedies must be revisited in light of the explosion in understanding of mechanisms of action of small molecule effectors of which actein and cimicifugoside (from black cohosh) are only two examples.

Palvanil, a non-pungent capsaicin analogue, inhibits inflammatory and neuropathic pain with little effects on bronchopulmonary function and body temperature

N-Palmitoyl-vanillamide (palvanil) is a non-pungent capsaicinoid, found in low amounts in Capsicum and shown to rapidly desensitize transient receptor potential vanilloid type-1 (TRPV1) channels to the action of capsaicin and to exert analgesic effects after local administration. We have investigated here if systemic administration of palvanil to mice causes two typical adverse events of TRPV1 agonists, i.e. profound changes in body temperature and bronchoconstriction, and if it can still produce effective inhibition of inflammatory and chronic pain in different experimental models. Varying doses of palvanil were tested subcutaneously and acutely on body temperature in vivo or, or as a bolus, on bronchopulmunary function ex vivo, in comparison with capsaicin. Intraperitoneal palvanil was also tested against formalin-induced nocifensive behavior and carrageenan-induced oedema and thermal hyperalgesia, acutely, and against mechanical allodynia and thermal hyperalgesia in mice with spared nerve injury (SNI) of the sciatic nerve, after repeated administration over 7 days from SNI. Palvanil, at therapeutically relevant doses, produced significantly less hypothermia and bronchoconstriction than capsaicin. Palvanil (0.5-2.5 mg/kg) abolished formalin-induced nocifensive behavior and strongly attenuated SNI-induced mechanical allodynia and thermal hyperalgesia and carrageenan-induced oedema and thermal hyperalgesia. Systemic administration of the non-pungent capsaicinoid, palvanil, produces, at least in mice, much less of those side effects typical of TRPV1 agonists (hypothermia and bronchoconstriction), whilst being very effective at reducing pain and oedema. Thus, palvanil might be developed further as a novel pharmacological treatment for chronic abnormal pain.

Attenuation of visceral nociception by α-bisabolol in mice: investigation of mechanisms

Background

We previously described the visceral antinociceptive property of α-bisabolol (BISA) in mouse models of visceral nociception induced by cyclophosphamide and mustard oil (MO). This study examined the effect of BISA in mouse models of visceral nociception induced by acetic acid, capsaicin, formalin, and the contribution of the nitric oxide system, α₂, K_ATP, 5-HT₃ and TRPV1 receptors to the effect of BISA on MO-evoked nociceptive behaviors. Mice were pretreated orally with BISA (50, 100 and 200 mg/kg) or vehicle, and the pain-related behavioral responses to intraperitoneal administration of acetic acid or intracolonic injection of MO were analyzed.

Results

BISA significantly suppressed the nociceptive behaviors in a dose-unrelated manner. The antinociceptive effect of BISA (50 mg/kg) was show to be glibenclamide resistant, but it was not blocked by pretreatment with the other antagonists tested. In the open-field test that detects sedative or motor abnormality, mice received 50 mg/kg BISA did not show any per se influence in ambulation frequency.

Conclusions

However, their precise antinociceptive mechanisms of action have not been determined.

Predictive validity of behavioural animal models for chronic pain

Rodent models of chronic pain may elucidate pathophysiological mechanisms and identify potential drug targets, but whether they predict clinical efficacy of novel compounds is controversial. Several potential analgesics have failed in clinical trials, in spite of strong animal modelling support for efficacy, but there are also examples of successful modelling. Significant differences in how methods are implemented and results are reported means that a literature-based comparison between preclinical data and clinical trials will not reveal whether a particular model is generally predictive. Limited reports on negative outcomes prevents reliable estimate of specificity of any model. Animal models tend to be validated with standard analgesics and may be biased towards tractable pain mechanisms. But preclinical publications rarely contain drug exposure data, and drugs are usually given in high doses and as a single administration, which may lead to drug distribution and exposure deviating significantly from clinical conditions. The greatest challenge for predictive modelling is, however, the heterogeneity of the target patient populations, in terms of both symptoms and pharmacology, probably reflecting differences in pathophysiology. In well-controlled clinical trials, a majority of patients shows less than 50% reduction in pain. A model that responds well to current analgesics should therefore predict efficacy only in a subset of patients within a diagnostic group. It follows that successful translation requires several models for each indication, reflecting critical pathophysiological processes, combined with data linking exposure levels with effect on target.

Evaluation of anti-inflammatory and antinociceptive effects of D-002 (beeswax alcohols)

D-002, a mixture of six higher aliphatic alcohols purified from beeswax, displayed anti-inflammatory effects in carrageenan-induced pleurisy and cotton pellet granuloma in rats. The aim of the present study was to confirm the anti-inflammatory properties of D-002 and to explore its potential analgesic effects. Xylene-induced mouse ear oedema was used to assess the anti-inflammatory effect, acetic acid-induced writhing and hot plate responses for the analgesic activity, and the open field and horizontal rotarod tests for motor performance. For anti-inflammatory tests, mice were randomised into a negative vehicle control and five xylene-treated groups: the vehicle, D-002 (25, 50 and 200 mg/kg) and indomethacin 1 mg/kg (reference drug). Treatments were given for 15 days. Effects on oedema formation and myeloperoxidase (MPO) activity were tested. For analgesia and motor performance tests, mice were randomised into a vehicle control and D-002-treated groups (25, 50 and 200 mg/kg). Two sets of experiments were done, which included acute and repeat (15 days) dosing. D-002 (25, 50 and 200 mg/kg) significantly decreased xylene-induced ear oedema (44.7, 60.8 and 76.4%, respectively) and the increase of MPO activity induced by xylene (38.0, 47.0 and 57.0%, respectively), while indomethacin significantly inhibited xylene-induced oedema (59.9%) and MPO activity (57.5%). Single and repeat doses of D-002 (25, 50 and 200 mg/kg) decreased the acetic acid-induced writhing responses by 21.2, 28.2 and 40.1%, for the single doses; 25.2, 35.1 and 43.2%, respectively, for the repeat doses, but did not affect the hot plate, open field and rotarod behaviours. Aspirin 100 mg/kg significantly decreased acetic acid-induced abdominal constrictions and morphine (5 mg/kg) significantly increased the latency of the hot plate response. This study confirmed the anti-inflammatory effects of D-002 and demonstrated its analgesic effects on the acetic acid-induced writhing, but not on the hot plate response, which suggests that the antinociceptive effects of D-002 could be related to its anti-inflammatory activity.

Evidence of TRPV1 receptor and PKC signaling pathway in the antinociceptive effect of amyrin octanoate

Previous studies from our group investigated the antinociceptive property of amyrin octanoate, a synthetic compound derivative from natural precursor alpha, beta-amyrin, against nociceptive response induced by acetic acid and formalin. Here, we investigated some of the mechanisms of action underlying the antinociceptive effects of amyrin octanoate. Amyrin octanoate given intraperitoneally (0.001-1 mg /kg) or intrathecally (10-1000 ng /site) caused dose-dependent and long-lasting inhibition of acetic acid-induced visceral nociception, with mean ID(50) values of 0.003 (0.001-0.005) mg/kg and 122.4 (60.8-246.6) ng/site, respectively. In the capsaicin- and glutamate-induced paw licking, amyrin octanoate caused significant and dose-dependent inhibition of both nociceptive responses, with ID(50) values of 1.36 and 0.04 mg/kg, respectively. Furthermore, amyrin octanoate also reduced significantly the nociception caused by intrathecal injection of glutamate, substance P and capsaicin, with inhibitions of 36+/-11%, 67+/-10% and 78+/-5%, respectively. The antinociception caused by amyrin octanoate in the acetic acid test was significantly attenuated by neonatal pretreatment of mice with capsaicin, but seems to involve mechanisms independent of G(i/o) protein, opioidergic, serotonergic, noradrenergic and cholinergic system, since it was not affected by pertussis toxin, naloxone, yohimbine, mecamylamine or atropine. In addition, amyrin octanoate reduced thermal and mechanical hyperalgesia induced by bradykinin and phorbol myristate acetate in rats, without affecting similar responses caused by prostaglandin E(2). Taken together, the present results shown that octanoate amyrin produces antinociceptive and antihyperalgesic effects, through an interaction with capsaicin-sensitive fibers and the inhibition of the PKC signaling pathway.

A possible mechanism for anxiolytic and antidepressant effects of alpha- and beta-amyrin from Protium heptaphyllum (Aubl.) March

In the present study, we examined the anxiolytic and antidepressant effects of the mixture of alpha- and beta-amyrin (AMY), pentacyclic triterpenes isolated from the stem bark resin of Protium heptaphyllum. These effects of AMY were demonstrated by the open-field, elevated-plus-maze, rota rod, forced swimming, and pentobarbital-induced sleeping time tests, in mice. In the open-field test, AMY at the doses of 10, 25 and 50 mg/kg, after intraperitoneal or oral administrations, significantly decreased the number of crossings, grooming, and rearing. All these effects were reversed by the pre-treatment with flumazenil (2.5 mg/kg, i.p.), similarly to those observed with diazepam used as a positive standard. In the elevated-plus-maze test, AMY increased the time of permanence and the number of entrances in the open arms. On the contrary, the time of permanence and the number of entrances in the closed arms were decreased. All these effects were also completely reversed by flumazenil, an antagonist of benzodiazepine receptors. In the pentobarbital-induced sleeping time test, AMY at the same doses significantly increased the animals sleeping time duration. In the rota rod test, AMY did not alter motor coordination and, thus, was devoid of effects, as related to controls. Since AMY, at the doses of 10 and 25 mg/kg, showed a sedative effect in the open field test, lower doses (2.5 and 5.0 mg/kg) were used in the forced swimming test, producing a decrease in the immobility time, similarly to that of imipramine, the positive control. The effect of AMI was greater when it was administered 15 min after imipramine (10 mg/kg). However, the antidepressant AMY effects were not altered by the previous administration of paroxetine, a selective blocker of serotonin uptake. In addition, AMY effects in the forced swimming test were totally blocked by reserpine pretreatment, a drug known to induce depletion of biogenic amines. In conclusion, the present work evidenced sedative and anxiolytic effects of AMY that might involve an action on benzodiazepine-type receptors, and also an antidepressant effect where noradrenergic mechanisms will probably play a role.

Endogenous opiates and behavior: 2005

This paper is the 28th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2005 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity, neurophysiology and transmitter release (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); immunological responses (Section 17).

Detoxification rates of wild herbivorous woodrats (Neotoma)

The detoxification systems of mammalian herbivores are thought to have evolved in response to the ingestion of plant secondary compounds. Specialist herbivores consume high quantities of secondary compounds and are predicted to have faster rates of Phase 1 detoxification compared to generalist herbivores. We tested this hypothesis by comparing the performances of a specialist (Neotoma fuscipes) and generalist (Neotoma lepida) herbivore using hypnotic state assays. Herbivores foraging in nature were live trapped and injected with hexobarbital (100 mg/kg). We measured the length of time in the hypnotic state as the time in which the animal was unable to right itself twice in 30 s. The specialist metabolized hexobarbital 1.7 times faster than the generalist (F(1, 19) = 9.31, P = 0.007) as revealed by its significantly shorter time spent in the hypnotic state (56+/-9 min vs. 87+/-8 min, respectively). The results are consistent with the hypothesis that specialists have faster rates of Phase 1 detoxification. This is the first evaluation of the detoxification capability of mammalian herbivores foraging under natural conditions. Hypnotic state assays have broad potential applications to the study of vertebrate-plant interactions.

Application of Pharmacological Approaches to Plant–Mammal Interactions

The dominant theory in the field of mammalian herbivore-plant interactions is that intake, and therefore tolerance, of plant secondary metabolites (PSMs) is regulated by mechanisms that reduce absorption and increase detoxification of PSMs. Methods designed by pharmacologists to measure detoxification enzyme activity, metabolite excretion, and most recently, drug absorption, have been successfully applied by ecologists to study PSM intake in a variety of mammalian study systems. Here, we describe several pharmacological and molecular techniques used to investigate the fate of drugs in human that have potential to further advance knowledge of mammalian herbivore-plant interactions.