Garcinia oblongifolia, Trees or shrubs, 5-15 m tall, to 30 cm in diam. Bark dark gray. Branchlets usually with interrupted rings. Petiole ca. 1 cm; leaf blade oblong, obovate-oblong to oblanceolate, 5-10 * 2-3.5 cm, subleathery, midvein slightly raised adaxially, secondary veins 10-18 pairs, tertiary veins reticulate, base cuneate, margin reflexed, apex acute or obtuse. Plant dioecious; flowers solitary or in an umbel-like cyme; pedicels 3-7 mm. Male flowers: sepals suborbicular, equal, 3-5 mm. Female flowers: sepals and petals similar to those of males. Bioassay-guided fractionation of the acetone extract of the bark of Garcinia oblongifolia has resulted in the isolation of three new xanthones, oblongixanthones A-C (1-3), three new polyprenylated benzoylphloroglucinols, oblongifolins E-G (4-6), and 12 known compounds. Oblongifolins I (5) and J (6) are the first natural products that have similar structural features to those of two known oxidation products of garcinol.