Rosana S. S. Barreto

Borneol, a Bicyclic Monoterpene Alcohol, Reduces Nociceptive Behavior and Inflammatory Response in Mice

Borneol, a bicyclic monoterpene, has been evaluated for antinociceptive and anti-inflammatory activities. Antinociceptive and anti-inflammatory activities were studied by measuring nociception by acetic acid, formalin, hot plate, and grip strength tests, while inflammation was prompted by carrageenan-induced peritonitis. The rotarod test was used to evaluate motor coordination. Borneol produced a significant (P < 0.01) reduction of the nociceptive behavior at the early and late phases of paw licking and reduced the writhing reflex in mice (formalin and writhing tests, resp.). When the hot plate test was conducted, borneol (in higher dose) produced an inhibition (P < 0.05) of the nociceptive behavior. Such results were unlikely to be provoked by motor abnormality. Additionally, borneol-treated mice reduced the carrageenan-induced leukocytes migration to the peritoneal cavity. Together, our results suggest that borneol possess significant central and peripheral antinociceptive activity; it has also anti-inflammatory activity. In addition, borneol did not impair motor coordination.

β-Cyclodextrin-complexed (-)-linalool produces antinociceptive effect superior to that of (-)-linalool in experimental pain protocols.

Many plants produce (−)‐linalool, a plant‐derived monoterpene alcohol, including members of the Lamiaceae (mints) and Lauraceae family (laurels, cinnamon, rosewood). The anti‐inflammatory and analgesic effects of (−)‐linalool have been widely suggested for various studies. Poor chemical stability and short half‐life restrain the clinical applications of some essential oil and monoterpenes, including (−)‐linalool. However, β‐cyclodextrin (β‐CD) has been used to increase solubility and stability of lipophilic compounds and also to improve the pharmacological effects. In this study, the antinociceptive effect of (−)‐linalool and (−)‐linalool/β‐CD was examined using the acetic acid writhing reflex, formalin and hotplate tests in rodents. (−)‐Linalool and (−)‐linalool/β‐CD demonstrated strong antinociceptive activity in all the chemical‐ and heat‐induced mice models (p < 0.01 or p < 0.001). These findings imply the involvement of both peripheral and central antinociceptive mechanisms. In peritonitis induced by carrageenan, isolated monoterpene or β‐CD complex also reduced total leucocyte migration and TNF‐α levels in peritoneal fluid. The inclusion complexes, (−)‐linalool/β‐CD, revealed that the antinociceptive effect was significantly (p < 0.01) improved when compared with (−)‐linalool alone. Such results were unlikely to be provoked by any motor abnormality. Together, our results suggest that β‐CD might represent an important tool for improvement of analgesic and anti‐inflammatory profiles of (−)‐linalool and other water‐insoluble compounds, such as lipophilic monoterpenes or essential oils.

A Systematic Review of the Wound-Healing Effects of Monoterpenes and Iridoid Derivatives

The search for more effective and lower cost therapeutic approaches for wound healing remains a challenge for modern medicine. In the search for new therapeutic options, plants and their metabolites are a great source of novel biomolecules. Among their constituents, the monoterpenes represent 90% of essential oils, and have a variety of structures with several activities such as antimicrobial, anti-inflammatory, antioxidant and wound healing. Based on that, and also due to the lack of reviews concerning the wound-healing activity of monoterpenes, we performed this systematic review—which provides an overview of their characteristics and mechanisms of action. In this search, the terms “terpenes”, “monoterpenes”, “wound healing” and “wound closure techniques” were used to retrieve articles published in LILACS, PUBMED and EMBASE until May 2013. Seven papers were found concerning the potential wound healing effect of five compouds (three monoterpenes and two iridoid derivatives) in preclinical studies. Among the products used for wound care, the films were the most studied pharmaceutical form. Monoterpenes are a class of compounds of great diversity of biological activities and therapeutic potential. The data reviewed here suggest that monoterpenes, although poorly studied in this context, are promising compounds for the treatment of chronic wound conditions.

Neuroprotective Effect of Natural Products on Peripheral Nerve Degeneration: A Systematic Review

Peripheral nerve injury (PNI) is a serious public health problem that is linked with motor, sensory and autonomic deficits. Given the fact that this type of disorder leads to a decreased quality of life in most patients and adherence of available drugs is limited and have adverse effects, we investigated the efficacy of natural products in a PNI model. The search terms plants, medicinal, nerve regeneration, nerve crush, sciatic nerve as well as MeSH terms or free-text words were used to retrieve English language articles in PubMed, Scopus, Web of Science and LILACS published until July 2015. After sciatic nerve crush, natural products have improved significantly motor performance, sensory function and electrical conductance measured over weeks. Among the pharmacological targets suggested by the action of natural products, there were citations on the activation of the antiapoptotic signaling pathway, modulation in the expression of pro-inflammatory cytokines and neurotrophic factors. The systematic review provides scientific evidence that natural products are pharmacologically effective in the treatment of PNI such as sciatic nerve crush.

Evidence for the involvement of TNF-α and IL-1β in the antinociceptive and anti-inflammatory activity of Stachys lavandulifolia Vahl. (Lamiaceae) essential oil and (-)-α-bisabolol, its main compound, in mice.

ETHNOPHARMACOLOGICAL RELEVANCE Stachys lavandulifolia Vahl (Lamiaceae) is a medicinal plant widely used in Turkey and Iranian folk medicine due to its analgesic and anti-inflammatory properties, but little is known about its essential oil. AIM OF THIS STUDY We studied the antinociceptive and anti-inflammatory effects of S. lavandulifolia essential oil (EOSl) and (-)-α-bisabolol (BIS), its main compound, in algogen-induced orofacial nociceptive behavior in mice, and assessed the possible involvement of pro-inflammatory cytokines in these profiles. MATERIALS AND METHODS The GC-FID and GC-MS analysis of EOSl demonstrated the presence of (-)-α-bisabolol (56.4%), bicyclogermacrene (5.3%), δ-cadinene (4.2%) and spathulenol (2.9%) as the main compounds. Male Swiss mice were pretreated with EOSl (25 or 50mg/kg, p.o.), BIS (25 or 50mg/kg, p.o.), morphine (3mg/kg, i.p.) or vehicle (saline 0.9% with two drops of tween 80, 0.2%), before formalin- (20μl, 2%), capsaicin- (20μl, 2.5µg) or glutamate- (20μl, 25Mm) injection into the right upper lip (perinasal area) in mice. The anti-inflammatory profile of EOSl or BIS (50mg/kg) was assessed by the inflammatory response induced by carrageenan (2% in 0.2mL) in mice (pleurisy model). RESULTS Our results showed that p.o. treatment with EOSl and BIS displayed significant inhibitory (p<0.05 or p<0.01 or p<0.001) effects in different orofacial pain tests on mice, but BIS proved to be more effective, significantly reducing nociceptive behavior in all tests including both phases of the formalin test. The analgesic effect is not related to any abnormality since EOSl- or BIS-treated mice exhibited no performance alteration in grip strength. Moreover, EOS1 and BIS exhibited a significant anti-inflammatory effect (p<0.001) in the pleurisy model of inflammation, which seems to be related to a significant reduction (p<0.05) of the pro-inflammatory cytokine TNF-α in BIS treatment, and of the pro-inflammatory cytokine IL-1β (p<0.01) in EOS1 treatment. CONCLUSION Our results corroborate the use of S. lavandulifolia in traditional medicine as an analgesic and anti-inflammatory, which seems to be related to (-)-α-Bisabolol, the main compound of EOSl.

Evaluation of wound healing activity of atranorin, a lichen secondary metabolite, on rodents

The aim of this study was to investigate the wound healing activity of atranorin cream (Patent requested) on excision wounds. Seventy-two male rats were anesthetized and an excisional wound was performed. Then the rats were randomly assigned into three groups: untreated control group; atranorin 1 (group treated with 1% AT ointment); and atranorin 5 (group treated with 5% AT ointment). Six animals of each group were euthanized 3, 7, 14 or 21 days after surgical procedures and the wounded areas were analyzed and removed. Serial histological sections were obtained and stained by histochemical techniques (Hematoxilin-Eosin-HEand Sirius red) and immunohistochemical techniques. Topical application of atranorin reduced wound areas, induced earlier granulation tissue formation, increased cell proliferation, improved collagenization and modulated the myofibroblasts differentiation when compared to control animals. It is suggested that atranorin modulates the wound healing process. These data suggest that this formulation based on atranorin extracted from Cladina kalbii AHTI may be a new biotechnological product for wound healing clinical applications.

Indole Alkaloids from Marine Sources as Potential Leads against Infectious Diseases

Indole alkaloids comprise a large and complex class of natural products found in a variety of marine sources. Infectious diseases remain a major threat to public health, and in the absence of long-term protective vaccines, the control of these infectious diseases is based on a small number of chemotherapeutic agents. Furthermore, the emerging resistance against these drugs makes it urgently necessary to discover and develop new, safe and, effective anti-infective agents. In this regard, the aim of this review is to highlight indole alkaloids from marine sources which have been shown to demonstrate activity against infectious diseases.

Evaluation of the anti-inflammatory and antinociceptive effects of the essential oil from leaves of Xylopia laevigata in experimental models.

Xylopia laevigata (Annonaceae) is a medicinal plant used in folk medicine to treat pain and inflammation. Thus, we investigated the possible antioxidant, antinociceptive, and anti-inflammatory effects of X. laevigata leaf essential oil (EOX) in animal models. Our EOX sample showed the presence of γ-muurolene (17.78%), δ-cadinene (12.23%), bicyclogermacrene (7.77%), and α-copaene (7.17%) as main compounds. EOX presented a strong antioxidant potential according to the DPPH, TBARS, and nitrite production tests. Additionally, pretreatment with EOX, in mice, also significantly produced (P < 0.05 or P < 0.001) antinociceptive effect by reduction of nociceptive behavior (in formalin and writhing tests). The EOX showed c-Fos label in the olfactory bulb, piriform cortex, and periaqueductal gray. Acute administration of EOX exhibited a significant (P < 0.01 or P < 0.001) anti-inflammatory profile in the carrageenan-induced peritonitis and by the carrageenan-induced hindpaw edema tests in mice. Our results provide evidence for the use of X. laevigata by traditional medicine practitioners in the management of pain and inflammatory disorders.

Bioassay-guided evaluation of antinociceptive effect of N-salicyloyltryptamine: a behavioral and electrophysiological approach.

We investigated the antinociceptive and nerve excitability effects of the N-salicyloyltryptamine (NST) NST-treated mice exhibited a significant decrease in the number of writhes when 100 and 200 mg/kg (i.p.) were administered (i.p.). This effect was not antagonized by naloxone (1.5 mg/kg, i.p.). NST inhibited the licking response of the injected paw when 100 and 200 mg/kg were administered (i.p.) to mice in the first and second phases of the formalin test. Because the antinociceptive effects could be associated with neuronal excitability inhibition, we performed the single sucrose gap technique and showed that NST (3.57 mM) significantly reduced (29.2%) amplitude of the compound action potential (CAP) suggesting a sodium channel effect induced by NST. Our results demonstrated an antinociceptive activity of the NST that could be, at least in part, associated to the reduction of the action potential amplitude. NST might represent an important tool for pain management.

New perspectives for chronic pain treatment: a patent review (2010-2016)

ABSTRACT Introduction: Chronic pain is a major problem of public health worldwide and is responsible for the increase in health costs. The therapeutic options available in the market for the treatment of chronic pain are often rather ineffective due to; the high number of adverse reactions, tolerance and dependence, reducing the quality of life, pharmacotherapy adherence and functional capacity. Hence, several studies have been conducted in the search for new treatment alternatives for chronic pain syndromes. Areas covered: This review brings together the therapeutic patents published over the past six years reporting the discovery of new drugs for the treatment of chronic pain, based on the perspective that these compounds are candidates for the management of chronic pain conditions. Expert opinion: Over the past 6 years, several pharmaceutical companies, as well as universities and researchers, have synthesized a series of compounds, which have been shown to be effective in controlling chronic pain in preclinical studies. These findings nurture the hope of discovering new therapeutic options for chronic pain. However, such studies are in early stages and there is a long and hard path to be followed until these compounds can become chemical entities available to the public.