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Introduction: Kaurane diterpenes, notably xylopic acid, have demonstrated important biological activities including analgesia, anti-oxidant, antimicrobial and cytotoxicity. The fruits of Xylopia aethiopica have been reported to be a rich source of kaurane diterpenes., Objective: An analytical approach for detailed imaging and characterisation of selected kaurane diterpenes was developed using matrix-assisted laser desorption/ionisation high-resolution mass spectrometry (MALDI-HRMS) imaging techniques and high-performance liquid chromatography-high resolution electrospray ionisation-tandem mass spectrometry (HPLC-HRESI-MS n ) studies, respectively., Methods: The images of the compounds were constructed based on selected ions from their HRESI-MS spectra. The matrix employed comprised a solution of α-cyano-4-hydroxycinnamic acid (HCCA) in acetonitrile-water with trifluoroacetic acid (TFA). HPLC-HRESI-MS n measurements were conducted on an LTQ-Orbitrap spectrometer equipped with a heated electrospray ionisation (HESI)-II source., Results: The analytical strategy adopted showed the spatial distribution of the compounds in the fruits of X. aethiopica based on the dominant ions at m/z 301.2163 [M + H - HOCOCH 3 ] + and m/z 399.1932 [M + K] + for xylopic acid, m/z 317.2111 [M + H] + and m/z 355.1670 [M + K] + for 15-oxo-ent-kaur-16-en-19-oic acid and m/z 303.2319 [M + H] + for ent-kaur-16-en-19-oic acid. The fragmentation patterns of the compounds were proposed based on the HRESI-MS n measurements., Conclusions: The study revealed the spatial variability, differential behaviours and specificity of the selected kaurane diterpenes in the fruit, seed and pericarp. The compounds under study were predominantly restricted to the pericarp of the fruit with trace amounts in the seed., (© 2019 John Wiley & Sons Ltd.)

Background: Fruit extracts of Xylopia aethiopica are used traditionally in the management of pain disorders including headache and neuralgia. An animal model of vincristine-induced sensory neuropathy was developed after repeated intraperitoneal injection in rats and used in the present work to study the effects of the ethanolic extract of X. aethiopica (XAE) and its diterpene xylopic acid (XA) in vincristine-induced neuropathic pain. Materials and Methods: Vincristine (0.1 mg kg-1 day-1) was administered during two cycles of five consecutive days to induce chemotherapy-induced neuropathic pain. Static tactile anti-allodynic, anti-hyperalgesic, and cold anti-allodynic effects of XAE (30-300 mg kg-1) and XA (10-100 mg kg-1) were assessed using Von Frey filaments of bending forces of 4, 8, and 15 g, the Randall-Selitto paw pressure test, and cold water (4.5°C), respectively. Results: Administration of vincristine caused the development of allodynia and hyperalgesia with no significant motor deficit, spontaneous pain, and foot deformity. XAE (30-300 mg kg-1) and XA (10-100 mg kg-1) exhibited anti-hyperalgesic, tactile, and cold anti-allodynic properties with XA exhibiting greater potency than XAE. Pregabalin (10-100 mg kg-1) used as control produced similar effect. Conclusion: These findings establish the anti-allodynic and anti-hyperalgesic effects of the ethanolic fruit XAE and its major diterpene XA in vincristine-induced neuropathtic pain. [ABSTRACT FROM AUTHOR]