The family Ebenaceae consists of five genera and about 450 species of trees of which 20 species are used for medicinal purposes in the Asia-Pacific region. Ebe-naceae and particularly Diospyros species have attracted a great deal of interest for their dimers and oligomers of naphthoquinones, which are antibacterial, antiviral, monoamine oxidase inhibitors, and cytotoxic. Ting et al. made the interesting observation that isodiospyrin is cytotoxic via direct binding topoisomerase I, which limits the access of the enzyme to the DNA substrate and prevents both DNA relaxation and kinase activities of topoisomerase I (15). Therefore, an interesting development from Ebenaceae would be a systematic investigation of naphthoquinone for topoisomerase inhibition.
Diospyros sumatrana Miq. (Diospyros flavicans [Wall.] Hiern, Diospyros dumosa King & Gamble, Diospyros decipiens King & Gamble, Diospyros tubicalyx Ridl., Diospyros vestita Bakh., Diospyros velutinosa Bakh., Diospyros hendersoni Ridley.), is a tree that grows to a height of 30 m tall and a girth of 100 cm in Indonesia, Thailand, and Malaysia (Sabah, Borneo) in lowland rainforest up to 1500 m. The stems are hairy when young. The leaves are simple, elliptic, ovate, oblong, 3.5-20 X 1.2-6.5 cm, the apex is acuminate, the base is pointed, and the midrib sunken above. There are 3-11 pairs of secondary nerves. The male flowers are 5-merous in 3-10 flowered subsessile cymes, and show 16 anthers. The female flowers are four-merous, salver-shaped, and show a four-locular ovary. The fruits are globose, 1.2 X 2.4 cm, with a 2.5-cm diameter calyx (Fig. 83). Malays drink a decoction of roots as a protective remedy. The plant has not been studied for its pharmacological potentials.
Diospyros toposioides King & Gamble, or arang, kayu arang (Malay), is a tree that grows to a height of 13 m and a girth of 60 cm in lowland rainforests of Malaysia (Borneo). The leaves are simple, oblong, oblong-ovate, 16-33 X 4-14 cm, the apex is acuminate, the base is rounded, and the midrib is sunken above; the secondary nerves are inconspicuous and loping at margin. The male flowers are in three-flowered axillary cymes and show 35-96 anthers. The female flowers are four-merous and show a eight-locular hairy ovary. The fruits are globose, 5 cm in diameter on a 3-cm-wide calyx (Fig. 84). In
Malaysia, the seeds are poisonous and used to catch fish. The plant has not been studied for its pharmacological potentials. The ichthyotoxic property could involve some naphtho-quinones and/or saponins.
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