Spondias tuberosa, commonly known as imbu,Portuguese pronunciation: [ũˈbu], [ĩˈbu] Brazil plum, or umbu, is native to northeast Brazil, where it grows in the Caatinga, the chaparral scrub that grows wild across dry lands of the Sertão. The round fruit is light yellow to red in colour, around 2–4 cm in size, and has a leathery shell. The flesh is soft and juicy, with a sweet taste and distinct aroma. The fruit comes from a small tree, seldom higher than 6 m, with an expansive crown of up to 10 m in diameter. The fruit of the imbu are round and can be of varying size: they can be as small as cherries or as large as lemons. The peel is smooth and green or yellow when the fruit ripen, the small firm fruits are juicy and flavorful and their succulent flesh hides a large dark pit.
The name of this tree and fruit comes from the indigenous phrase y-mb-u, which means tree that gives drink. The productive cycle of this wild, spontaneously growing tree begins after ten years of growth. It bears fruit once a year and can produce up to 300 kilos of fruit in a single harvest when it reaches maturity. Due to its robust root system, a great network of tubers that can store liquid throughout the Sertão s dry season, the imbu tree can hold up to 3,000 liters of water during the dry months.
4-Hydroxy-4-methylpentanoic acid (UMB68) is a tertiary alcohol, similar in structure to the drug GHB. The molecule has been synthesized and tested on animals in order to further research the effects of GHB. UMB68 has been shown to bind selectively to the GHB receptor ligand in binding assays, yet does not bind to GABAergic receptors. As such, it can provide a useful tool in studying the pharmacology of the GHB receptor in absence of GABAergic effects.
3-Chloropropanoic acid (also 3-chloropropionic acid) or UMB66 is a drug used in scientific research. It is structurally related to GHB and binds to the GHB receptor, but has no affinity for GABA receptors. It is also an active ingredient in some herbicide blends. Overdose may cause unconsciousness and/or convulsions.