Pterocarpus indicus (commonly known as Amboyna wood, Malay padauk, Papua New Guinea rosewood, Philippine mahogany, Andaman redwood, Burmese rosewood, narra and asana in the Philippines, angsana, or Pashu padauk) is a species of Pterocarpus native to southeastern Asia, northern Australasia, and the western Pacific Ocean islands, in Cambodia, southernmost China, East Timor, Indonesia, Malaysia, Papua New Guinea, the Philippines, the Ryukyu Islands, the Solomon Islands, Thailand, and Vietnam.
Pterocarpus indicus was one of two species (the other being Eysenhardtia polystachya) used as a source for the 16th- to 18th-century traditional diuretic known as lignum nephriticum.
Many populations of Pterocarpus indicus are seriously threatened. It is extinct in Vietnam and possibly in Sri Lanka and Peninsular Malaysia. It was declared the national tree of the Philippines in 1934 by Governor-General Frank Murphy of the Insular Government of the Philippine Islands through Proclamation No. 652.
It is a large deciduous tree growing to 30–40 m tall, with a trunk up to 2 m diameter. The leaves are 12–22 cm long, pinnate, with 5–11 leaflets, the girth is 12–34 m wide. The flowers are produced in panicles 6–13 cm long containing a few to numerous flowers; flowering is from February to May in the Philippines, Borneo and the Malay peninsula. They are slightly fragrant and have yellow or orange-yellow petals. The fruit is a semiorbicular pod 2–3 cm diameter, surrounded by a flat 4–6 cm diameter membranaceous wing (wing-like structure) which aids dispersal by the wind. It contains one or two seeds, and does not split open at maturity; it ripens within 4–6 years, and becomes purple when dry. The central part of the pod can be smooth (f. indica), bristly (f. echinatus (Pers.) Rojo) or intermediate.
Most Pterocarpus species prefer seasonal weather but P. indicus prefer rainforests.
Note: Pterocarpus macrocarpus, a similar species native to Burma, is referred to as "Rosewood" throughout South East Asia. P. macrocarpus is usually harder than P. indicus. When in burl form both are referred to as Amboyna Burl.
The hardwood, which is purplish, is termite-resistant and rose-scented. The wood known in Indonesia as amboyna is the burl of the tree, named after Ambon, where much of this material was originally found. Often amboyna is finely sliced to produce an extremely decorative veneer, used for decoration and in making of furniture and keys on a marimba.
It is a premium timber species suitable for high grade furniture, lumber and plywood for light construction purposes. It is also used for cartwheels, wood carving and musical instruments.
The flower is used as a honey source while leaf infusions are used as shampoos. Both flowers and leaves were said to be eaten. The leaves are supposedly good for waxing and polishing brass and copper. It is also a source of kino or resin.
The leaves of narra are also used in traditional medicine to treat a variety of health problems. Narra leaves contain flavonoids. Flavonoids are antioxidants that provide health benefits to humans, such as anti-inflammatory and anti-allergic benefits. Flavonoids in narra leaves may be capable of preventing damage to your kidneys.
In folk medicine, it is used to combat tumors. This property might be due to an acidic polypeptide found in its leaves that inhibited growth of Ehrlich ascites carcinoma cells by disruption of cell and nuclear membranes. It was also one of the sources of lignum nephriticum, a diuretic in Europe during the 16th to 18th centuries. Its reputation is due to its wood infusions, which are fluorescent.
The tree is recommended as an ornamental tree for avenues and is sometimes planted in Puerto Rico as a shade and ornament. The tall, dome-shaped crown, with long, drooping branches is very attractive and the flowers are spectacular in areas with a dry season. It is very easily propagated from seed or large stem cuttings, but suffers from disease problems. It is widely planted as a roadside, park, and parking lot tree.
In agroforestry, it maintains ecosystem fertility and soil stability. Narra is a leguminous plant that is capable of fixing nitrogen by forming endosymbiotic relationships with nitrogen-fixing bacteria that lives in its root nodules. Leguminous plants, such as narra, are responsible for transforming nitrogen into a usable form.
In the Philippines, a permit is required to cut the tree (Nara), but nevertheless the popular sturdy wood is widely used for construction and furniture projects.
It is the national tree of the Philippines. It is also the provincial tree of Chonburi and Phuket in Thailand.
- World Conservation Monitoring Centre (1998). "Pterocarpus indicus". IUCN Red List of Threatened Species. 1998: e.T33241A9770599.
- Simon Gardner, Pindar Sidisunthorn and Lai Ee May 2011. Heritage Trees of Penang. Penang: Areca Books. ISBN 978-967-57190-6-6
- International Legume Database & Information Service: Pterocarpus indicus Archived 8 June 2011 at the Wayback Machine
- Muyskens, M.; Ed Vitz (2006). "The Fluorescence of Lignum nephriticum: A Flash Back to the Past and a Simple Demonstration of Natural Substance Fluorescence". Journal of Chemical Education. 83 (5): 765. Bibcode:2006JChEd..83..765M. doi:10.1021/ed083p765.
- Pangilinan, Jr., Leon (3 October 2014). In Focus: 9 Facts You May Not Know About Philippine National Symbols. National Commission for Culture and the Arts.
- National Symbols. National Commission for Culture and the Arts. Retrieved on 7 April 2021.
- Revised Forestry Code of the Philippines (Presidential Decree No. 705). Forest Management Bureau, Department of Environment and Natural Resources. Retrieved 7 April 2021.
- Danida Seed Leaflet: Pterocarpus indicus (pdf file) Archived 9 April 2008 at the Wayback Machine
- Purdue University New Crops: Pterocarpus indicus Archived 5 February 2007 at the Wayback Machine
- Carandang, 2004
- Saputri et.al., 2007
- In Focus: 9 Facts You May Not Know About Philippine National Symbols – National Commission for Culture and the Arts (en-US).