Hevea brasiliensis Euphorbiaceae

Alstonia boonei (Apocycaceae), Balanophora elongata (Balanophoraceae), Ficus variegata (Moraceae), Hevea brasiliensis (Euphorbiaceae), Erythroxylum coca (Erythroxylaceae), Semi-synthetic from a-Amyrin... 

Commercial rabber has been isolated from Castilla elas-tica (Moraceae), Manihot glaziovii (Euphorbiaceae), Lan-dolphia spp. (Apocynaceae), Taraxacum kok-saghyz (As-teraceae), Hevea brasiliensis (Euphorbiaceae), and Parthenium argentatum (guayule, Asteraceae). Despite intense interest in finding other rabber sources, virtually all commercial natural rabber comes from Hevea brasiliensis or closely related species (Euphorbiaceae) (Rogers, 1981). 

Apiosc gum +9° Di-O-isopropyl- idene 83° In glycosidic union in Umbellifercae, Compositeae, Leguminoseae families, in Hevea brasiliensis, (Euphorbiaceae) and in leaves and fibre of Posidonia australis... 

Hevea brasiliensis (Euphorbiaceae) Acetone cyanohydrin (linamarin) s 58 30 5.5-6 115... 

HNLs are found in over 3000 higher plant species, like Rosaceae, Euphorbiaceae, Linaceae and Filitaceae, in several bacteria, and in some insects [5, 6]. For cyanohydrin synthesis, mainly five HNLs have been used the (R)-selective HNLs from Prunus amygdalus (PaHNL) and Linurn usitatissimum (l.ul INI.) and the (S)-selective ones from Hevea brasiliensis (HfeHNL), Manihot esculenta (MeHNL), and Sorghum bicolor (SfcHNL) [1]. 

Hevea chitinase/lysozyme hevamines A B (Class I) (30 kDa proteins hevein-like N-terminal CBD) Hevea brasiliensis (rubber tree) (Euphorbiaceae) [latex] Chitin... 

Hevea brasiliensis (rubber tree) (Euphorbiaceae) pathogen induced... 

Rubber is a natural product that exists as a colloidal dispersion named latex in the sap of certain plants from various families such as Moraceae, Compositae or Euphorbiaceae. From this last family, Hevea brasiliensis is the most common plant that produces natural rubber for practical use. The latex has rather large colloidal particles (in aqueous medium) with diameters up to 5 m (although the average is 0.5 jim). 

Natural rubber (NR) is elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloid produced by some plants (Hevea brasiliensis, a member of the spurge family, Euphorbiaceae). The plants are tapped by making an incision in the bark of the tree and collecting the sticky, milk-coloured latex sap, which is refined into usable rubber. The purified form of NR is the chemical polyisoprene, which can also be produced synthetically. NR is used in many applications and products, as is synthetic rubber. It is normally very stretchy and flexible and extremely waterproof. 

The natives of tropical America were preparing articles from the rubbery exudates of Hevea spp. (Euphorbiaceae) and Castilla spp. (Moraceae) trees well before discovery by Europeans in the early 17th century. Following the developments of vulcanization and other treatments, an enormous exploitation of rubber trees, particularly of Hevea brasiliensis, growing in the delta of the Amazon River and in its upper reaches west of Manaus, took place from 1827 onward. Large fortunes were made by a few European entrepreneurs at the expense of the lives of many local and imported laborers. After some difficulties, rubber trees were cultivated in Malaysia in 1880, and subsequently in neighboring countries, from which most of the natural rubber of today is derived. Following severe competition from syn-... 

Of the polyterpenes rubber, gutta-percha, and balata, our discussion will be restricted to the technically most important product, rubber. About 2,000 species of higher plants produce rubber but only a few of them, mainly from the families Apocynaceae, Asclepiadaceae, Compositae, Euphorbiaceae, and Moraceae, do so in sufficient quantity as to make its extraction technically worthwhile. A few of the more important species are listed in Table 5. The main source of rubber is the rubber tree Hevea brasiliensis. Achras sapota, the chicle of which provides the basic ingredient of chewing gum, is also included in the list. 

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