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Introduction: Uncaria species is a type of climbing vine found across Southeast Asia, East Asia, and South America. The leaf and hook (claw-like) parts of Uncaria plants have traditionally been used to treat pain, neurological disorders, hypertension, stroke, rheumatism, and other ailments. Chemically, the Uncaria species is rich in indole and oxindole alkaloids. Methods: In this study, we investigated the potential antinociceptive activity of a rare Malaysian Uncaria species – Uncaria attenuate (UA) on rats using the hot plate method. The alkaloid profile of UA was analysed using various chromatographic techniques and spectroscopic methods. Results: In the hot plate test, UA methanolic leaf extract (500 mg/kg) and alkaloid leaf extract (100 mg/kg) given orally demonstrated suppression of pain sensation when compared to control animals. This is evident as reduced pain effect encountered over a substantial latency period. The antinociceptive activity of methanolic and alkaloid UA leaf extracts were significantly reversed in animals pre-treated with a non-selective opioid antagonist (naloxone) (2 mg/kg i.p.). Extensive chromatographic analyses revealed that the major alkaloid marker of UA is a monoterpene oxindole alkaloid. Conclusion: These findings suggest that methanolic and alkaloid extracts of UA leaves as antinociceptive agents. This effect is likely mediated by a mechanism involving interactions with the central opioid receptors. Malaysian plant Uncaria species can hold prospective as a herbal plant for pain treatment. [ABSTRACT FROM AUTHOR]