Analysis of cassine and spectaline in the Senna spectabilis ethanolic extracts by capillary zone electrophoresis with indirect UV detection.

INTRODUCTION: 2,6-Disubstituted piperidin-3-ols are an important group of piperidine alkaloids found in species such as Senna spectabilis, whose main constituents include cassine and spectaline, compounds with relevant pharmacological activity. The analysis of these compounds is challenging due to the complexity of plant extracts and the absence of chromophores capable of absorbing ultraviolet (UV) radiation. OBJECTIVE: This paper presents a new analytical method to separate and quantify the non-UV-absorbing alkaloids present in ethanol extracts from S. spectabilis flowers using capillary zone electrophoresis (CZE) with indirect UV detection. METHODOLOGY: The optimized CZE method employs a background electrolyte containing 60 mM histidine (His), 15 mM α-cyclodextrin, 20% acetonitrile (ACN), and pH-adjusted to 4.7 with acetic acid (AcOH). RESULTS: The limit of detection (LOD) values was 10.2 and 13.9 mg L-1 for cassine and spectaline, respectively. For both analytes, the precision data were better than 2% of relative standard deviation (RSD) for migration times and peak areas. To evaluate the applicability of the developed method, ethanolic extracts from S. spectabilis flowers were prepared and analyzed. CONCLUSIONS: Thereby, the method proved to be efficient and complementary to conventional techniques, offering a cost-effective alternative in the quantification of the non-UV-absorbing piperidine alkaloids present in plant extracts.

Stephalagine, an aporphine alkaloid from Annona crassiflora fruit peel, induces antinociceptive effects by TRPA1 and TRPV1 channels modulation in mice.

Pain relief represents a critical unresolved medical need. Consequently, the search for new analgesic agents is intensively studied. Annona crassiflora, a native species of the Brazilian Savanna, represents a potential source for painful treatment. This study aimed to investigate the antinociceptive potential of A. crassiflora fruit peel, focusing on its major alkaloid, stephalagine, in animal models of pain evoked by the activation of transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) channels. Male C57BL/6/J mice were submitted to formalin-, cinnamaldehyde-, and capsaicin-induced nociception tests to assess nociceptive behavior, and to the open-field and rotarod tests for motor performance analyses. Moreover, the stephalagine's effect was tested on capsaicin- and cinnamaldehyde-induced Ca2+ influx in spinal cord synaptosomes. In silico assessments of the absorption, distribution, metabolism and central nervous system permeability of stephalagine were carried out. The ethanol extract and alkaloidal fraction reduced the nociception induced by formalin. When administered by oral route (1 mg/kg), stephalagine reduced the spontaneous nociception and paw edema induced by TRPV1 agonist, capsaicin, and by TRPA1 agonists, cinnamaldehyde- and formalin, without altering the animals' locomotor activity. The prediction of in silico pharmacokinetic properties of stephalagine suggests its capacity to cross the blood-brain barrier. Furthermore, this alkaloid reduces the capsaicin- and cinnamaldehyde-mediated Ca2+ influx, indicating a possible modulation of TRPV1 and TRPA1 channels, respectively. Together, our results support the antinociceptive and anti-edematogenic effects of the A. crassiflora fruit peel and suggest that these effects are triggered, at least in part, by TRPV1 and TRPA1 modulation by stephalagine.

Stephalagine, an aporphinic alkaloid with therapeutic effects in acute gout arthritis in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Gout is an inflammatory disease characterized by the accumulation of monosodium urate crystals (MSU) in the joints, leading to severe pain and inflammation. Stephalagine is a Brazilian Savanna aporphine alkaloid isolated from Annona crassiflora Mart. Fruit peel, that has been popularly used to treat rheumatism and have been described with antinociceptive properties. However, no studies evaluated the possible therapeutic properties of stephalagine in arthritic pain. AIM OF THE STUDY: To evaluate the possible antinociceptive and anti-inflammatory effects of stephalagine in an acute gout attack in mice. MATERIALS AND METHODS: Adult male wild type C57BL/6/J/UFU mice (20-25 g) were used (process number 018/17). The treated group received stephalagine (1 mg/kg, by gavage) and the vehicle group received saline (10 mL/kg, by gavage), both 1 h before the MSU crystals (100 µg/ankle joint) administration. All groups were analyzed for mechanical allodynia, thermal hyperalgesia, overt pain-like behaviors, and edema development at 2, 4, 6 and 24 h after injections. Synovial fluid and the ankle articulation from the injected joint were collected 4 h after administrations for myeloperoxidase enzyme activity, IL-1ß measurement, and histological analysis. RESULTS: Stephalagine had a significant antinociceptive effect on mechanical allodynia, when compared to vehicle group at 2-24 h after intra-articular injection of MSU and 2 h for spontaneous and cold thermal sensitivity. Stephalagine was also able to significantly reduce the articular edema (45 ± 1%), the activity of the myeloperoxidase enzyme (37 ± 6%), and IL-1ß levels (43 ± 3%). The histological analysis confirms that stephalagine dramatically reduced the number of infiltrating inflammatory cells (75 ± 6%) in MSU injected animals. Also, stephalagine treatment did not alter the uric acid levels, xanthine oxidase activity, AST and ALT activities, urea and creatinine levels, neither cause any macroscopic changes in the mice's weight, deformations, changes in the coat, or feces. CONCLUSION: Stephalagine may be an alternative for the management of gout, once it was able to induce antinociceptive and anti-inflammatory effects without causing adverse effects on the evaluated parameters.