Botanically known as Cosmos caudatus, it is sometimes called ‘wild cosmos’ by locals here but it is mostly refered to via its Malay name, ulam raja, which translates into ‘king vegetable’. Native to tropical America, it was first introduced to Philippines via the Spaniards, according to Plant Resources of South East Asia (PROSEA). The pinnate to pinnatipartite leaves of this plant are consumed as a leafy vegetable, usually in the raw form, but sometimes also cooked and mixed with coconut sauce and chillies. It constitutes as one of the more common raw plant leaves eaten a salad-like form, called ‘ulam’ by the local Malay community as well as those in Indonesia and Malaysia.
For the uninitiated, the leaves of ulam raja tastes raw and somewhat astringent. When crushed, the leaves emit an odour that is reminiscent of mango. It is considered as a medicinal herb which is believed to possess the ability to cleanse the blood and strengthen bones due to its high calcium content. From my research, a preliminary one which was done with my then postgraduate colleague, the dried leaves of this plants contain high amounts of potent antioxidants.
It contains 0.3% of proteins,o.4% of fats and carbohydrates, it also rich in lacsium and vitamin A. Its leaf has high antioxidant (AEAC) property, each 100 grams of the fresh leaves have the same antioxidant property to the 2400 mg of ascorbic L-acid. It contains more than 20 types of antioxidant substances that have been identified in ulam raja. The main anti oxidant substances are due to the existence of protosianidin in dimer, through hecsamer, cuersetin glycoside, chlorogenic acid, neochlorogenic acid, kripto-chlorogenic acid and (+)- catcher.
The plant itself can grow quite tall, up to 3 m tall but is an annual or a short-lived perennial herb. It produces dainty, attractive pink flowers when mature. It should not be confused with the yellow- and orange-flowered Cosmos sulphureus as both species are similar vegetatively and have some vernacular names (randa midang in West Java) in common.
This plant is rather easy to grow. It thrives in a sunny spot outdoors with well draining, fertile and moist soil. It is a big drinker and demands a constant supply of food. Under optimal conditions, it grows quickly, flowers and sets seeds very readily. Plants self seed easily and can quickly become a weed in a garden. Harvesting of leaves can commence once plants are 6 weeks old and subsequent ones can be done every 3 weeks. Regular harvesting will stimulate the production of useful and edible foliage and helps to delay flowering.
Ulam raja is used in traditional medication because it can repair the blood flow and purify the blood from toxic substances. It also can strengthen the bones. The extract chloroform from its leaf has costunolide, stigmasterol, lutein and bipyridine that cab inhibit the activity of some bacteria and fungi like candida albicans, Bacillus subtilis and also E. Choli.