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The first phytochemical investigation of the twig extract of Uvaria leptopodaresulted in the isolation and identification of three new tetrahydroxanthene-1,3(2H)-diones, uvarialeptones A–C, two new oxidized hexadiene derivatives, uvarialeptols A and B, together with ten known compounds. Their structures were elucidated by spectroscopic techniques and mass spectrometry. Uvarialeptones A and B were unprecedented tetrahydroxanthene-1,3(2H)-dione dimers which exhibited a cyclobutane ring via [2 + 2] cycloaddition from uvarialeptone C and 9a-O-methyloxymitrone, respectively. The structure of uvarialeptone A was confirmed by X-ray diffraction analysis using Mo Kα radiation. Compound 3inhibited NO production at an IC50value of 6.7 ± 0.1 μM.