Gen info
- Didymocheton is a genus of flowering plants in the family Meliaceae. It includes 41 species. The genus was first named by Carl Ludwig Blume in 1825.  Most of the species currently accepted were, until recently, included in the genus Dysoxylum. A genetic study published 2021 found Dysoxylum to be polyphyletic, and Didymocheton was revived and recircumscribed.(14)
- Didymocheton gaudichaudianus is a species of rainforest tree in the family Meliaceae.
- The species was first described by Adrien-Henri de Jussieu in 1830.
- Etymology: The former genus name Dysoxylum derives from Greek words Dys, meaning "bad" and xylon meaning "wood", referring to the ill-smelling wood. (•) The species epithet gaudichaudianus honors French botanist Charles Gaudichaud-Beaupré. (13)

Botany
• Igiu is a tree reaching a height of 10 to 20 meters. Leaves are crowded at the ends of the branches, 20 to 60 centimeters long, pinnate with 10 or more pairs of leaflets. Lower leaflets are usually ovate, less than 10 centimeters long; the median and upper ones are oblong, 20 centimeters or more in length. Flowers are pale yellowish, hairy, about 1 centimeter long, 5-parted, borne in axillary drooping panicles which are about 40 centimeters long. Fruit is yellow, hairy, depressed-globose, about 1.5 to 2 centimeters in diameter, containing red seeds.

• Ivory mahogany is a large tree growing up to 36 m (118 ft) in height with a straight trunk up to 80 cm (31 in) diameter. The bark is smooth and often has teaspoon-sized depressions in it. Buttress roots are a feature of this tree and may reach up to 2.5 m (8 ft 2 in) high and 3.5 m (11 ft) wide. The very large leaves are produced in whorls and clustered towards the ends of the branches. They are imparipinnate  with up to 14 pairs of leaflets, and measure up to 125 cm (49 in) in length. This arrangement produces large spherical clusters of foliage (see gallery). Leaflets are highly asymmetric at the base with one side of the leaf blade wider than the other. They measure up to 30 by 8 cm (11.8 by 3.1 in). Inflorescences are thyrses, about 70 cm (28 in) long, and produced in or close to the leaf axils. Flowers are a pale cream or green, 5-merous, with an unpleasant smell. Fruits are capsules about 3 cm (1.2 in) diameter which are covered in fine brown hairs. They have five segments and contain up to 10 seeds about 1 cm (0.39 in) long. (13)

Distribution
- Native to the Philippines.
- In thickets and forests at low altitudes from Cagayan to Sorsogon in Luzon, and in Mindoro, Palawan, Masbate, Leyte, Negros, Mindanao, and Basilan.
- Also native to Bismarck Archipelago, Christmas I., Jawa, Lesser Sunda Is., Maluku, New Guinea, Queensland, Samoa, Solomon Is., Sulawesi, Tonga, Vanuatu, Wallis-Futuna Is. (8)

Constituents
- Study yielded 4 new compounds, dysoxylins A-D, belonging to the tetranortriterpenoid family. (see study below) (1)
- Leaf extract yielded (1), ß-sitosterol (2), polyprenols (3) and triglycerides (4). The cytotoxic activity of the extract may be attributed to the synergistic effects of the compounds. (see study below) (5)
- Bark yielded a new limonoid, gaudichaudysolin A. (6)
- Study isolated squalene (1), polyprenol (2), triglycerides (3), and ß-sitosterol (4) from dichlormethane extract of leaves.(see study below) (9)

Properties
- Juice of fresh bark is bitter.
- Freshly cut wood with variable smell, faint, sometimes resembling shallots. (7)
- Bark considered febrifuge, antitussive, emmenagogue, and emetic.
- Leaves considered abortifacient, emmenagogue, and parturient. (7)
- Studies have suggested antiviral, cytotoxic, anticancer, spasmolytic properties.

Toxicity concern
- Medicinal use of the bark is reported to have killed two people in Papua New Guinea. (7) Note: No details or studies found on these fatalities. However, the plant is not reported to be toxic. The fatalaties reported were
attributed to its use as ean metic (induced vomiting).

Parts used
Bark, sap, leaves.

Uses
Edibility
- No reports found on edibility.
- The fruits is a reported foord source for figbirds and metallic starling.
Folkloric
- Decoction of bitter fresh bark is given for coughs.
- Powdered bark, with water, used as febrifuge; with wine, used as emmenagogue.
- Powdered bark also used as emetic.
- In Java, juice of bark used as emetic; also, externally, as an astringent.
- In Vanuatu, the juice expressed from 10 leaves with some water, used to facilitate childbirth. As abortifacient, strong decoction made up from 12 sun-dried leaves.
- In Papua New Guinea, the leaves and bark are used for treating rigid limbs, facial distortion in children, lumps under the skin, skin irritations, and sexually transmitted diseases. Also used for fish poisoning and convulsions. Decoction of chopped leaves used as cure for aches and pains; also for lung hemorrhage. (4)
- Juice of leaves, mixed with water, used to facilitate childbirth. Twelve dried leaves used to make a strong tea to promote an abortion. (7)
- In Vanuatu, decoction of dry leaves used as abortifacient. In Papua New Guinea, juice of bark used as emmenagogue. (10)
- In the Western Pacific, bark or stem bark used as component in a polyherbal concoction for the treatment of ciguatera fish poisoning. (11)
- The Tetun ethnic people in West Timor, Indonesia, use decoction leaves orally and as bath for treatment of malaria. (12)
Others
- Insecticidal: Infusion of bark used as piscicidal and insecticidal. (7)
- Wood: A general purpose timber. (7)

Studies
• Dysoxylins / Antiviral: Study yielded 4 new compounds, dysoxylins A-D and were found to exhibit potent antiviral activity against respiratory syncitial virus (RSV). The compunds were shown to have anti-RSV EC50 activities in the range of 1.0-4.0 µg/mL in cytopathic effect inhibition and plaque reduction assays. (1)
• Spasmolytic Activity: In an ethnobotanical survey of reproductive behavior in Vanuatu, five plant species, including D gaudichaudianum, were selected. Preliminary screening was done to identify possible estrogenic activity as well as effects on isolated rat uteri. D gaudichaudianum presented most interest with its spasmolytic activity. (2)
• Chemical Constituents / Cytotoxicity / Leaves: Crude dichloromethane leaf extract of Dysoxylum gaudichaudianum was tested for cytotoxicity against breast cancer (MCF-7) and colon cancer (HT-29) cells. The extract showed high cytotoxic activities for both cancer cell lines. Purification of the dichlormethane leaf extract yielded squalene (1), ß-sitosterol (2), polyprenols (3) and triglycerides (4). The cytotoxic activity of the extract may be attributed to the synergistic effects of the compounds. (5)
• Gaudichaudysolin A / Bark: A new limonoid, gaudichaudysolin A, was isolated from the bark of Dysoxylum gaudichaudianum. (6)
• Cytotoxicity Against Cancer Cell Lines / Leaves: Study isolated squalene (1), polyprenol (2), triglycerides (3), and ß-sitosterol (4) from dichlormethane extract of leaves. The compounds were evaluated for anti-proliferative activities against three human cancer cell lines, viz. breast (MCF-7) and colon (HT-29 and HCT-116), and a normal cell line, human dermal fibroblast neonatal (HDFn). The anti-proliferative activities of 1-4 were highest against HT-29, followed by MCF-7. Overall, compounds 1-4 were more cytotoxic to the breast and colon cancer cell lines than to the normal cell line. (9)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Dysoxylins A−D, Tetranortriterpenoids with Potent Anti-RSV Activity from Dysoxylum gaudichaudianum / Jian Lu Chen, Michael R Kernan, Shivanand D et al / J. Nat. Prod., 2007, 70(2): pp 312–315
DOI: 10.1021/np060398y
(2)
Maternity and medicinal plants in Vanuatu I. The cycle of reproduction / G Bourdy and A Walter / Journal of Ethnopharmacology, 37 (1992) 179-196
(3)
Maternity and medicinal plants in Vanuatu II. Pharmacological screening of five selected species / G Bourdy, C Francois, C Andary and M Boucard / Journal of Ethnopharmacology, Volume 52, Issue 3, 5 July 1996, Pages 139-143 / doi:10.1016/0378-8741(96)01404-3
(4)
Anti-Respiratory Syncytial Virus Agents from Phytomedicine / Damian Chukwu Odimegwu, Thomas Grunwald and Charles Okechukwu Esimone
(5)
Chemical constituents and cytotoxicity of the leaves of Dysoxylum gaudichaudianum (A. Juss.) Miq. / Consolacion Y. Ragasa , Vincent Antonio S. Ng, Mariquit M. De Los Reyes, Emelina H. Mandia, Glenn G. Oyong, and Chien-Chang Shen / Der Pharma Chemica, 2014, 6(5): pp 182-187
(6)
Gaudichaudysolin A, a New Limonoid from the Bark of Dysoxylum gaudichaudianum / Yuta Nagakura, Reiko Yamanaka, Yusuke Hirasawa, Takahiro Hosoya, Abdul Rahman, Idha Kusumawati, Noor Cholies Zaini, and Hiroshi Morita* / Heterocycles / Special issue, 2010; Vol 80, No. 2: pp.1471-1477 / DOI: 10.3987/COM-09-S(S)106
(7)
Dysoxylum gaudichaudianum / Useful Tropical Plants
(8)
Didymocheton gaudichaudianus / Synonyms / KEW: Plants of the World Online
(9)
Cytotoxic Compounds from Dysoxylum gaudichaudianum (A. Juss.) Miq. / Mariquit de los Reyes, Glenn Oyong, Vincent Antonio Santos Ng et al / International Journal of Pharmacognosy and Phytochemical Research, 2016;  8(4): pp 668-674
(10)
Dysoxylum gaudichaudianum / RC Cambie, A A Brewis / Antifertility Plants of the Pacific
(11)
Traditional remedies used in the Western Pacific for the treatment of ciguatera poisoning / G. Bourdy, P. Cabalion, P. Amade and D. Laurenta / Journal of Ethnopharmacology, 1992; 36: pp 163-174
(12)
Plants used in traditional medicine for treatment of malaria by Tetun ethnic people in West Timor Indonesia / Maximus M Taek, Bambang Prajogo EW, Mangestuti Agil / Asian Pacific Journal of Tropical Medicine, 2018; 11(11): pp 630-637
(13)
Didymocheton gaudichaudianus / Wikipedia
(14)
Didymocheton / Wikipedia
(15)
Ivory mahogany / CQC Landcare Network

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