Gen info
- Syzygium is a genus of flowering plants in the myrtle family, Myrtaceae, which comprises about 1200 species.
- Syzygium claviflorum is a tree in the Myrtaceae family.
- The species was first described in 1841 by German physician and botanist Ernst Gottlieb von Steudel (1783-1841), who published the description in the second edition of his work Nomenclator botanicus (1840-1). (2)
- Etymology: The species epithet claviflorum derives from Latin, meaning "club-shaped flower."

Botany
• An evergreen tree that grows some 10-20m tall in Southeast Asia, 3-15m tall in Zhongguo, China. Trees in the North Queensland Rainforests grow quickly to a large size, reaching some 180 to 270cm diameter. Bark is often rather pale, greyish-white to greyish-brown. Leaves have a depressed midrib and a grooved petiole on the upper surface, the blade is 6.5-13.2 by 2.9-5.8cm in size. Oil dots that are quite variable in size can be seen with a hand-lens. There are about 16-37 lateral veins on each side of the midrib. Inflorescence bracts are deciduous, and absent at full flower opening, anthesis. In the flowers the calyx tube, hypanthium, and pedicel are around 10-20mm long together, the calyx tube is some 2-5mm in diameter, there are 4-5 rounded, small and inconspicuous calyx lobes, rarely greater than 0.5mm in length. Petals are 6-8, orbicular, when fully grown around 2-3mm in diameter, more or less cohering (largely as the apices of all petals fold into a cylinder at the center between the staminal filaments). There are up to 20-30 oil dots on the petals. Outer staminal filaments are some 3-8mm long. Anthers are roughly 0.8 by 0.5mm in size, with a terminal gland, reasonably conspicuous. Each locule has about 9-16 ovules. The rather stout style is some 3-8mm long, the same or slightly longer than the stamens. The edible fruit is of variable shape, from cylindrical to turbinate to pyriform, often galled and irregular, excavated at the apex, and when mature 11-14 by 9-10 mm in size. Calyx lobes are not obvious. The pericarp is succulent. Cells radiate from the endocarp to the exocarp. Seeds are about 7-8 by 7-8mm, with the testa apparently absent. The seedlings have about 3 pairs of reduced leaves, cataphylls, and before the first pair of true leave appear, these cataphylls are some present between the leaves at later stages. At the tenth leaf stage, conspicuously quadrangled or shortly winged twigs appear, with a lanceolate to ovate leaf, whose apex is acuminate to acute, and a cuneate base. Oil dots are numerous, just visible to the naked eye, clearly visible with a hand-lens. Seeds germinate between 38-95 days. (2)

Distribution
- Native to the Philippines.
- Also native to Andaman Is., Assam, Bangladesh, Borneo, Cambodia, China South-Central, East Himalaya, Hainan, India, Jawa, Laos, Malaya, Myanmar, New Guinea, Northern Territory, Queensland, Sri Lanka, Sulawesi, Thailand, Vietnam (1)
- IUCN listed as "Least Concern." However, in the Northern Territory, Australia, the plant is listed by the government as "Near Threatened." (2)

Constituents
- In a bioactive compound analysis of seeds and pulp, the seed extract was found to have higher amount of total tannin (302.2 mg TAE g dry extract), and flavonoids (1.37 mg QE dry extract) compared to pulp. (see study below) (3)

Properties
- Study suggest antioxidant property.

Parts used
Fruit.

Uses
Edibility
- Fruits are edible, eaten raw or pickled.
Folkloric
- No reported folkloric medicinal use in the Philippines.
Others
- Wood: Heartwood is golden brown, grayish brown or brown, with pink or purplish glints; fine textured, slightly interlocked grain, with resin deposits. Wood is heavy, moderately hard, somewhat durable, resistant to fungi and termites, but susceptible to wood borers. (4)
- Fodder: Fruit use as cattle feed.
- Tannin: Bark used for dyeing nets to increase their strength.
- Fuel: Wood make a good firewood.
- Construction use: A useful structural timber. Works well with ordinary tools, nailing, and pre-bored screwing. Used for making musical instruments, tool handles, furniture components, ship building, heavy carpentry, flooring, joinery, etc. (4)

Studies
• Antioxidant / Free Radical Scavenging Activity / Potential for Fruit Preservation / Fruit: Study evaluated the potentiality of seed (seed with kernel) and pulp (edible pulp with peel) as natural antioxidants. In DPPH and ABTS free radical scavenging assays, the seed extract exhibited significant (p<0.05) higher free radical scavenging and antioxidant properties compared to the pulp. The seed radical scavening capacity was comparable with natural and artificial antioxidants like ascorbic acid and BHT (butylated hydroxytoluene). Among identified phenolic compounds, epicatechin, catechin hydrate, and gallic acid were the most dominant in seed and pulp extracts. Bioactive and phenolic compounds highly correlated to antioxidant capacity as measured by DPPH and ABTS assays. Results suggest a source and immense potential to replace synthetic antioxidants in food preservation. (see constituents above) (3)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Syzygium claviflorum / KEW: Plants of the World Online
(2)
Syzygium claviflorum / Wikipedia
(3)
Free radical-scavenging capacity and HPLC-DAD screening of phenolic compounds from pulp and seed of Syzygium claviflorum fruit / Shafi Ahmed, Abdullah Jubair, Mohammad Afzal Hossain, Md Monir Hossain, Md Shofiul Azam, Mrityunjoy Biswas / Journal of Agriculture and Food Research, 2021; Volume 6: 100203 / DOI: 10.1016/j.jafr.2021.100203
(4)
Syzygium claviflorum / Kern Fern: Tropical Plants Database / Useful Tropical Plants

DOI: It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page. (Citing and Using a (DOI) Digital Object Identifier)