Anti-inflammatory and antinociceptive activity of Siparuna guianensis Aublet, an amazonian plant traditionally used by indigenous communities

ETHNOPHARMACOLOGICAL RELEVANCE

Siparuna guianensis Aublet leaves, known as negramina, are used by indigenous and local communities in Brazil and other countries in the Americas to treat pain and inflammatory diseases.

AIM OF THE STUDY

To characterize the chemical constituents and to evaluate the antioxidant, anti-inflammatory, antinociceptive and locomotor activities of the dichloromethane fraction (DF) of S. guianensis leaves. Also, an acute oral toxicity test was accomplished.

MATERIAL AND METHODS

The chemical characterization of DF was performed by ultra-high pressure liquid chromatography (UHPLC) analyses coupled with a high-resolution mass spectrometer. The antioxidant potential of DF was investigated using nitric oxide (NO) and hydroxyl radical (OH) scavenging test. The evaluation study of the anti-inflammatory activity was carried out in vitro by NO measurement in stimulated macrophages and, in vivo, by croton oil-induced ear edema, LPS-induced peritonitis, and zymosan-induced arthritis in mice. Different mechanisms of central and peripheral nociception were stimulated by acetic acid-induced writhing, formalin, and tail-flick tests. Besides that, the open field assay was performed.

RESULTS

UHPLC analyses of DF showed the presence of a mixture of glycosylated and methoxylated flavonoids. DF was able to scavenge NO and OH radicals in vitro and showed anti-inflammatory activity by inhibiting NO production in LPS-stimulated murine macrophages. Oral administration of DF considerably inhibited the ear edema after croton oil application and reduced the leukocyte infiltrated in LPS-induced peritonitis. In the inflammatory intra-articular zymosan-induced process, DF showed a significant reduction in the inflammatory area and of the cells in the synovial and connective tissues adjacent to the joint. Also, DF was able to reduce the intra-articular edema. In nociception models, the oral administration of DF considerably inhibited the acetic acid-induced writhings. The formalin test showed that DF attenuated the licking time in both phases, which suggested that DF reduce the nociception by central and peripheral mechanisms. In the tail-flick test, DF showed no activity. Besides that, DF did not affect the animal locomotion, and no acute toxicity was observed.

CONCLUSIONS

For the first time, the anti-inflammatory and antinociceptive activities of S. guianensis were reported, supporting its ethnopharmacological uses for some inflammatory diseases and painful conditions.

Preclinical studies indicate that INFLATIV, an herbal medicine cream containing Pereskia aculeata, presents potential to be marketed as a topical anti-inflammatory agent and as adjuvant in psoriasis therapy

OBJECTIVES

A previous study reported that the hexane fraction (HF) obtained from Pereskia aculeata leaves showed promising topical anti-inflammatory activity. Intending its future use in clinical practice, a herbal medicine cream named INFLATIV was developed. Its anti-inflammatory and antipsoriatic potential were investigated. INFLATIV was subjected to preliminary accelerated stability tests and to a degradation profile assessment.

METHODS

INFLATIV was prepared at 6% and 12%. The anti-inflammatory activity was assessed by croton oil single and multiple application challenge in mice. Mouse tail test was used for antipsoriatic potential investigation. Cutaneous atrophy test was performed. Preliminary accelerated stability tests were performed together with a degradation profile by GC-MS analysis.

KEY FINDINGS

The anti-inflammatory activity shown by INFLATIV was comparable to dexamethasone. However, the skin atrophy caused by that drug was not observed. INFLATIV modified skin parakeratotic differentiation into orthokeratosis, which revealed its antipsoriatic potential. The ingredients used were suitable to carry the bioactives as they were well permeated by the skin. The preliminary accelerated stability tests indicated that INFLATIV 6% is more stable than 12%.

CONCLUSIONS

The results demonstrated the relevant therapeutic and marketing potentials of INFLATIV, which is likely to be further evaluated in clinical trials for drug registration process with regulatory agencies.

In vivo wound healing activity of gels containing Cecropia pachystachya leaves

Objectives

To evaluate the in-vivo wound healing and in-vitro antioxidant activity of gels containing the ethyl acetate extract of Cecropia pachystachya (ECP) 2% and 5%, and to perform the chemical fingerprint of ECP by HPLC-DAD.

Methods

The wound healing activity of the gels was evaluated for 21 days, using the excision model in rats followed by histopathological and histomorphometric analysis. The in-vitro antioxidant effect of ECP was investigated using 1-diphenyl-2-picrylhydrazyl, reducing power, β-carotene bleaching and thiobarbituric acid reactive substances assays. Also, a HPLC analysis was performed to identify the chemical markers orientin, iso-orientin and chlorogenic acid.

Key findings

The group of animals treated with ECP 5% presented oedema and inflammatory infiltrate with less intensity than the other groups. Both ECP 2% and 5% gels showed less neovascularization and cellularity, and better tissue repair when compared to the control, which showed a younger and homogeneous tissue.

Conclusions

This study had demonstrated that the ECP gels promoted the acceleration of the healing process when compared to the control group. Wound contraction, angiogenesis, epithelialization and the collagen deposition support further evaluation of C. pachystachya leaves in the topical treatment and management of skin wounds.

Pereskia aculeata Miller leaves present in vivo topical anti-inflammatory activity in models of acute and chronic dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Pereskia aculeata Miller (Cactaceae), known as Barbados gooseberry, are used in Brazilian traditional medicine as emollients and to treat skin wounds and inflammation. This study investigated the topical anti-inflammatory activity of the hexane fraction (HF) obtained from the methanol extract of the leaves of this species in models of acute and chronic ear dermatitis in mice.

MATERIAL AND METHODS

Mice ear edema was induced by topical application of croton oil, arachidonic acid, capsaicin, ethyl-phenylpropiolate and phenol; and by subcutaneous injection of histamine. Ear biopsies were obtained to determine the levels of IL-1β, IL-6 and TNF-α cytokines by ELISA assay. Histopathological analysis was also performed to evaluate the HF activity in croton oil multiple application test. In addition, acute dermal irritation/corrosion test in rats was accomplished. HF chemical characterization was performed by GC-MS analysis.

RESULTS

HF intensively reduced the inflammatory process induced by all irritant agents used, except for arachidonic acid. This activity is related, at least in part, to the reduction of IL-6 and TNF-α cytokines levels. Moreover, when the glucocorticoid receptor antagonist mifepristone was used, HF failed to respond to the croton oil application.The results strongly suggested a glucocorticoid-like effect, which was reinforced by the presence of considerable amounts of sterol compounds identified in HF. The acute dermal irritaton/corrosion test showed no signs of toxicity.

CONCLUSIONS

This study showed that the acute and chronic anti-inflammatory activity of P. aculeata leaves is very promising, and corroborates to better understand their ethnopharmacological applications.

Topical application of the hexane fraction of Lacistema pubescens reduces skin inflammation and cytokine production in animal model

OBJECTIVES

The aim of this study was to investigate the acute topical anti-inflammatory effect of the hexane fraction (HLP) of Lacistema pubescens in mice.

METHODS

Ear oedema models induced by croton oil, arachidonic acid, phenol, histamine, ethyl phenyl propiolate and capsaicin. Histopathological analyses of ear tissue samples sensitized with croton oil were performed. Myeloperoxidase activity (MPO), the pro-inflammatory cytokine-inhibitory effect and dermatoxicity were also evaluated.

KEY FINDINGS

HLP (1, 0.5 and 0.1 mg/ear) resulted in a substantial reduction in skin thickness or tissue weight on all models tested, except for capsaicin-induced ear oedema, similar to dexamethasone (0.1 mg/ear) and/or indomethacin (0.5 mg/ear). Histopathological analyses and neutrophil-mediated MPO activity confirmed the topical anti-inflammatory effect of HLP. In addition, HLP reduced IL-1β, IL-6 and tumour necrosis factor-α cytokine levels. Sitosterol-rich fraction (SRF), obtained from HLP fractionation, reduced ear oedema on croton oil and phenol models at the same dose of dexamethasone (0.1 mg/ear). No dermotoxicity was observed.

CONCLUSIONS

The mechanism of action of HLP was associated with the inhibition of several pro-inflammatory mediators, including cytokines, arachidonic acid metabolites and histamine, which suggested a glucocorticoid-like effect, reinforced by the presence of the steroid sitosterol. This is the first report on anti-inflammatory activity of L. pubescens leaves.