Machaerium hirtum (Vell.) Stellfeld Alleviates Acute Pain and Inflammation: Potential Mechanisms of Action.

:Machaerium hirtum (Vell.) Stellfeld (Fabaceae) known in Brazil as "jacaranda de espinho" or "espinheira santa nativa" is a medicinal plant commonly used in folk medicine to treat ulcers, cough and diarrhea. This study aimed to investigate the anti-inflammatory and antinociceptive effects of hydroalcoholic extracts from M. hirtum twig (HEMh) using in vivo experimental models of nociception through the involvement of transient receptor potential channels, acid-sensing ion channel (ASIC), nitrergic, opioidergic, glutamatergic, and supraspinal pathways. Our results revealed an antinociceptive effect of HEMh mediated by the opioidergic, L-arginine-nitric oxide and glutamate systems, as well as by interactions with TRPA1/ASIC channels. The anti-inflammatory effect of HEMh evaluated with a xylene-induced ear edema and by the involvement of arachidonic acid and prostaglandin E2 (PGE2) showed involvement of the COX pathway, based on observed decreases in PGE2 levels. A phytochemical investigation of the HEMh led to the isolation of α-amyrin, ß-amyrin, allantoin, apigenin-7-methoxy-6-C-ß-D-glucopyranoside, and apigenin-6-C-ß-D-glucopyranosyl-8-C-ß-D-xylopyranoside. In conclusion, the acute oral administration of HEMh inhibits the nociceptive behavioral response in animals through the nitrergic, opioid, glutamatergic pathways, and by inhibition of the TRPA1 and ASIC channels, without causing locomotor dysfunction. In addition, its anti-inflammatory effect is associated with the COX pathway and decreased PGE2 levels.

Systematic Analysis of Monoterpenes: Advances and Challenges in the Treatment of Peptic Ulcer Diseases.

Peptic ulcer disease (PUD) is a multifactorial and complex disease caused by an imbalance of protective and aggressive factors (endogenous and exogenous). Despite advances in recent years, it is still responsible for substantial mortality and triggering clinical problems. Over the last decades, the understanding of PUD has changed a lot with the discovery of Helicobacter pylori infection. However, this disease continues to be a challenge due to side-effects, incidence of relapse from use of various anti-ulcer medicines, and the rapid appearance of antimicrobial resistance with current H. pylori therapies. Consequently, there is the need to identify more effective and safe anti-ulcer agents. The search for new therapies with natural products is a viable alternative and has been encouraged. The literature reports the importance of monoterpenes based on the extensive pharmacological action of this class, including wound healing and anti-ulcerogenic agents. In the present study, 20 monoterpenes with anti-ulcerogenic properties were evaluated by assessing recent in vitro and in vivo studies. Here, we review the anti-ulcer effects of monoterpenes against ulcerogenic factors such as ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), and Helicobacter pylori, highlighting challenges in the field.

Involvement of Opioid System, TRPM8, and ASIC Receptors in Antinociceptive Effect of Arrabidaea brachypoda (DC) Bureau.

Arrabidaea brachypoda (DC) Bureau is a medicinal plant found in Brazil. Known as "cipó-una", it is popularly used as a natural therapeutic agent against pain and inflammation. This study evaluated the chemical composition and antinociceptive activity of the dichloromethane fraction from the roots of A. brachypoda (DEAB) and its mechanism of action. The chemical composition was characterized by high-performance liquid chromatography, and this fraction is composed only of dimeric flavonoids. The antinociceptive effect was evaluated in formalin and hot plate tests after oral administration (10-100 mg/kg) in male Swiss mice. We also investigated the involvement of TRPV1 (transient receptor potential vanilloid 1), TRPA1 (transient receptor potential ankyrin 1), TRPM8 (transient receptor potential melastatin 8), and ASIC (acid-sensing ion channel), as well as the opioidergic, glutamatergic, and supraspinal pathways. Moreover, the nociceptive response was reduced (30 mg/kg) in the early and late phase of the formalin test. DEAB activity appears to involve the opioid system, TRPM8, and ASIC receptors, clearly showing that the DEAB alleviates acute pain in mice and suggesting the involvement of the TRPM8 and ASIC receptors and the opioid system in acute pain relief.