Gen info
- Prasoxylon is a genus of flowering plants in the family Meliaceae. It includes seven species.
-The genus was first described by Max Joseph Roemer in 1846. Most the the species currently accepted were until recently included in the genus Dysoxylum. A genetic study published in 2021 found Dysoxylum is polyphyletic, and Prasoxylon was revived and re-circumscribed. (13)
- Prasoxylon alliaceum is a polymorphic evergree tree in the mahogany family Meliaceae, renowned for the strong onion-like odor emitted by all the parts, which inspired its specific epithet alliaceum.
- Etymology: The specific epithet alliaceum derives from Latin meaning "onion-like", alluding to the onion-like scent emitted by crushed leaves and bark.

Botany
• Growth form: Tree to 38m tall. Trunk: Trunk to 80cm in diameter, with buttresses to 60cm tall and reaching outwards by about 1m. Foliage: Leaves 60cm long (occasionally to 120cm),with3-6 or occasionally 8 pairs of leaflets. Leaflets 7.5-25cm long by 2.5-7.5cm wide, opposite or sub-opposite, with an apical pair of leaflets, or appearing to have an apical leaflet, with the leaflet appearing as a small apical scar. Young leaves fist shaped, more or less pubescent. Leaves and bark usually with strong smell of onions.  Flowers: Flowers white or pinkish, 4-5 petaled. Petals 0.5-0.8cm long. Fruit: Fruits  to 7.5cm in diameter, subglobose or lobed, ripening dull reddish orange or reddish brown, with 1-4 seeds per fruit. (Flora & Fauna Web)

• Tree up to 38 m tall, all parts smelling strongly of onion; trunk up to 80 cm in diameter, fluted to 4 m at base with buttresses up to 60 cm tall and projecting 1 m from the trunk. • Leaves paripinnate, 3-6(-8)-jugate, up to 60(-120) cm long, subcoriaceous; petiole 5-15 cm long; petiolule 0.5-2 cm long; leaflet elliptical, ovate or subfalcate, 7.5-25 cm × 2.5-7.5 cm. • Inflorescence a pyramidal thyrse, up to 40 cm long, branchlets bearing cymules of 1-3 sweetly scented flowers. • Pedicel up to 4 mm long; flowers 4-5-merous; calyx shallowly cupular, 3 mm in diameter, margin 4-toothed; petals 4-5, linear, 5-8 mm long, white or pinkish; staminal tube glabrous to puberulous, bearing 8 or 10 anthers; pistil with 3-locular ovary and terete style. • Infructescence up to 25 cm long; fruit a subglobose capsule, up to 7.5 cm in diameter, sometimes lobed and constricted between the seeds, red. • Seeds 1-4 per capsule,
oblong-globose, red. (PROSEA)

Distribution
- Native to the Philippines. (11) (12)
- In Luzon: Cagayan, Camarines, Isabela, Laguna, Rizal; in Mindanao: Davao, Lanao, Surigao; in Negros, Palawan, Panay, Samar, Sibuyan. (11)
- In low and medium elevation primary rainforests, 0-1800m.
- From the Andaman Islands and peninsular Thailand throughout the Malesian Archipelago towards northern Australia and the Solomon Islands. (3)
- Also native to Andaman Is., Bismarck Archipelago, Borneo, Jawa, Lesser Sunda Is., Malaya, Maluku, Myanmar, New Guinea, Queensland, Solomon Is., Sulawesi, Sumatera, Thailand, Vietnam. (12)

Constituents
- HR-ESI-MS, FTIR, and NMR studies of stem bark isolated 8 ttirucallane-type riterpenoid compounds (1-8), including cneorin-NP36 (1), toonapubesin A (2), toonapubesin B (3), chisopanin M (4), 21 α-methylmelianodiol (5), 21 ß-methylmelianodiol (6), hispidone (7), and odoratone (8). (see study below)  (5)
- Study of stem bark isolated two 17-membered macrolides: alliaceumolide A (1), a new macrolide, with known ivorenolide B (2). The compounds were tested against two human cancer cell lines: MCF-7 and HeLa cell lines. (6)
- Study of ethanolic extract of stem bark identified 5 known steroids, 3ß,16ß-dihydroxy-24(S)-methyl cholestenol (1), ergosta-5,22-dien-3ß-ol (2), ergosta-7,24(28)-dien-3ß-ol (3), 22(E)-ergosta-6,22-dien-3ß,5α,8α-triol (4), and 20α-dihydroprogesterone (5). (8)
- Study of stem bark isolated five new mexicanolides (1-5), alliaxylines A-E, together with 2 known limonoids (6, 7). Tested for cytotoxic activity, (see study below) (9)
- Study isolated a new macrolide, Alliaceumolid A, together with known ivorenolide B. (Both compounds were tested for cytotoxicity against two cancer cell lines: MCF-7 and HeLa. (14)
- HR-ESI-MS, FTIR, and NMR study of stem bark isolated 8 tirucallne-type triterpenoid compounds (1-8): cneorin-NP36 (1), toonapubesin A (2), toonapubesin B (3), chisopanin M (4), 21-α methylmelianodiol (5), 21- methylmelianodiol (6), hispidone (7), and odoratone (8). (see study below) (15)

Properties
- Studies have suggested cytotoxicity, anticancer properties.

Parts used
Stem bark, roots..

Uses
Edibility
- Young leaves reportedly edible; boiled. Fresh young leaves used as spice to impart an onion-like flavor. Seeds also reportedly used with ginger and lemon/lime in the preparation of sauce for fish. (Caution: see toxicity below) (3) (7)
Folkloric
- No published info on folkloric medicinal use in the Philippines.
- In Malaysia, the Kensiu tribe of Lubuk Ulu Legong drink root decoction post-partum. (10)
Others
- Wood: Wood is whitish, light in weight, moderately hard, not resistant to insects. Heartwood is red-brown; sapwood, fawnish. Occasionally used for making boards or interior construction, planking, flooring, paneling, wood pallets, furniture making, veneer and plywood. (7)
- Seeds: Seeds are poisonous and contain dysoxylum acid. Used as vertebrate poison. (7)

Studies
• Anticancer / Stem Bark: Study evaluated the cytotoxic activity of D. alliance stem bark against MCF-7, A549, and CV-01 cell lines. HR-ESI-MS, FTIR, and NMR studies isolated 8 neurotically-type enteritides compounds (1-8), including cneorin-NP36 (1), toonapubesin A (2), toonapubesin B (3), chisopanin M (4), 21 α-methylmelianodiol (5), 21 ß-methylmelianodiol (6), hispidone (7), and odoratone (8). Compound 2, toonapubesin A, showed highest selectivity against A549 cancer cell lines with IC50 of 7.81 µM, with no activity towards CV-1 cells (fibroblast-like cells). Results suggest a potential source of natural products with anticancer properties. (5)
• Steroids / Stem Bark: Study of ethanolic extract of stem bark identified 5 known steroids, 3ß,16ß-dihydroxy-24(S)-methyl cholestenol (1), ergosta-5,22-dien-3ß-ol (2), ergosta-7,24(28)-dien-3ß-ol (3), 22(E)-ergosta-6,22-dien-3ß,5α,8α-triol (4), and 20α-dihydroprogesterone (5). Compounds showed weak to inactive effect against A549 lung cancer cell lines with IC50s ranging from 68.52 to ≥150 µM. (8)
• Cytotoxicity / Stem Bark: Study of stem bark isolated five new mexicanolides (1-5), alliaxylines A-E, together with 2 known limonoids (6, 7). Tested for cytotoxic activity, Compound 2 was most potent against two tested cell lines, MCF-7 and A549, with IC50s of 34.95 and 44.39 µM. (9)
• Targeted Triterpenoids / Cytotoxicity in Human Cancer and Normal Cells / Stem Bark: Study evaluated the stem bark of D. alliaceum, which have shown cytotoxic activity against MCF-7, A549, and CV-1 cell lines. HR-ESI-MS, FTIR, and NMR isolated 8 tirucallne-type triterpenoid compounds (1-8). Compound 2, toonapube4sin A, showed highest selectivity against A549 cancer cell lines with IC50 of 7.81 µM, with no activity towards CV-1 cells. (see constituents above) (15)
• 6-7-dimethoxydihydrocoumarin / Cytotoxic Activity against P-388 / Bark: Study evaluated an ethyl acetate bark extract of D. alliaceum for secondary metabolites. Analysis using spectroscopic methods and guided by TLC isolated the compound 6,,7-dimethoxydyhidrocoumarin. Cytotoxic activity testing against P-388 MTT leukemia cells obtained an IC50 of 39.210 g/mL and was declared inactive. (16)

Availability
- Wild-crafted.

Additional Sources and Suggested Readings
(1)
Dysoxylum alliaceum / AsianPlantNet
(2)
Dysoxylum alliaceum / National Parks: Flora & Fauna Web
(3)
Dysoxylum alliaceum / PCM Jansen . PROSEA: Plant Resources of South-East Asia
(4)
Dysoxylum / Wikipedia
(5)
Cytotoxic tirucallanes from Dysoxylum alliaceum stem barks in human cancer and normal cells lines / Sandra Amalia Riyadi, Al Arofatus Naini, Tri Mayanti, Kindi Farabi et al / Journal of Biologically Active Products from Nature, 2024; 14(2): pp 171-186 / DOI: 10.1080/22311866.2024.2347466
(6)
Alliaceumolide A: A rare undescribed 17-membered macrolide from Indonesian Dysoxylum alliaceum / Sandra Amalia Riyade, Al Arofatus Naini, Unang Supratman et al / Phytochemistry Letters, 2024; Vol 62: pp 73-77 / DOI: 10.1016/j.phytol.2024.07.004
(7)
Dysoxylum alliaceum / Ken Fern / Useful Tropical Plants
(8)
The Cytotoxic Evaluation of Steroids Isolated from Dysoxylum alliaceum (Blume) Blume ex A.Juss./ Sandra Amalia Riyadi, Al Arofatus Naini, Tri Mayanti, Unang Supratman et al / Molekul, 2024; 19(3): 471 /
DOI: 10.20884/1.jm.2024.19.3.11439
(9)
Alliaxylines A–E: five new mexicanolides from the stem barks of Dysoxylum alliaceum (Blume) Blume ex A.Juss / Sandra Amalia Riyadi, Al Arofatus Naini, Unang Supratman et al / Journal of Natural Medicines, 2024; Volume 78: pp 558-567 / DOI: 10.1007/s11418-024-01794-2
(10)
Traditional Medicinal Plants Used by the Kensiu Tribe of Lubuk Ulu Legong, Kedah, Malaysia / Nur Shahidah Mohammad, Pozi Milow, Hean Chooi Ong / Ethno Med., 2012; 6(3): pp 149-153 /
DOI: 10.31901/24566772.2012/06.03.02 / eISSN: 2456-6802 / pISSN: 0972-0073
(11)
Meliaceae: Prasoxylon alliaceum / Ed. by Pieter B. Pelser / Co's Digital Flora of the Philippines
(12)
Prasoxylon alliaceum / KEW: Plants of the World Onlline
(13)
Prasoxylon / Wikipedia
(14)
Alliaceumolide A: A rare undescribed 17-membered macrolide from Indonesian Dysoxylum alliaceum / Sandra Amalia Riyadi, Al Arofatus Naini, Tri Mayanti, Kindi Farabi, Unang Supratman et al / Phytochemistry Letters, 2024; Vol 62: pp 73-77 / DOI: 10.1016/j.phytol.2024.07.004
(15)
Targeted triterpenoids from Dysoxylum alliaceum stem barks as cytotoxic agents in human cancer and normal cells / Sandra Amalia Riyadi, Al Naini, Tri Mayanti, Kindi Farabi, Unang Supratman et al /
DOI: 10.21203/rs.3.rs-3851751/v1
(16)
6,7-dimethoxydihydrocoumarin Compound from Ethyl Acetate Extracts from Steambarks Dysoxylum Alliaceum and Cytotoxic Activity Against P-388 / Ois Nurcahyanti, Kartika Rahma / Journal of Tropical Pharmacy and Chemistry, 2022; 6(2) / DOI: 10.25026/jtpc.v6i2.405 / pISSN: 2087-7099 / eISSN: 2407-6090

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