Aloe species

In addition to hydroxyanthraquinones such as alizarin, which is derived from shikimate, glutamate and mevalonate precursors, higher plants produce some polyketide anthraquinones identical to those of microbial origin. Of particular interest is the cooccurrence in root extracts of Aloe species of the 2-methylanthraquinone chiysophanol (63) and the isomeric 1-methylanthraquinone aloesaponarin II (64), since in microorganisms 63 has only been isolated fi om fungal species whereas 64 is the product of a recombinant streptomycete (Figure 7). 

However according to Kiihl [36] this process may be followed by framework dealumination which involves the formation of extra-lattice Lewis acid AlO species ... 

Although A. vera sa.dA.ferox species are the most important commercial in the international markets, it is largely the presence of anthrones and polysaccharides content that determine the plants effectiveness for therapeutic activity. There are other Aloe species that could be promoted for similar purposes when those species contain one or both groups of bioactive compounds. The biological activities of the Aloe sp could be attributed to synergic actions of the components rather than from a single component 16). 

Aloe specie.s are characterized by aloin A/B, aloe-emodin and the non-laxative aloeresin.s (aloe.sin A-C). In addition some aloes contain aloino ide.s and substituted aloins (5- or... 

Aloe exhibited antitumor, anticarcinogenic, and cancer chemopreventive properties in animal models. According to a Russian report, treatment of experimental tumors in mice and rats with aloe juice contributed to reduction of tumor mass, metastatic foci, and metastasis frequency. Bioassay-guided purification of an aloe species afforded a hydroxyanthraquinone compound called aloe-emodine, which significantly inhibited P-388 lymphocytic leukemia and human neuroectodermal tumors implanted in mice 157,158 inhibited human hepatoma cell lines, Hep G2 and Hep 3B, human... 

In rats fed whole leaf powder of aloe (species unspecified) at doses of 2,4, or 8 g/kg daily for 90 days, some incidences of pigmentation of various organs was observed (Zhou et al. 2003). 

C15H10O5. Mr 270.24, orange needles, mp. 223 - 225 °C, uv 430 nm (C2H5OH), soluble in ether, benzene, and hot ethanol. A. is named after the aloe, the concentrated leaf juices of various Aloe species (A. ferox, A. barbadensis, Liliaceae) and occurs additionally in free form and as the corresponding anthrone glycosides in Rhamnus, Rheum, Rumex, and Cassia species. In addition to laxative action it also exhibits an antileukemic effect and is used as starting material for the synthesis of anthracycline antibiotics. 

Anthraquinone glycosides have long been used medicinally as cathartics and laxatives. Plant-derived drugs of this type include aloes Aloe species), cascara sagrada (Rhamnus purshiams), frangula (Rhamnus frangula), rhubarb (Rheum officinale), rumex or yellow dock (Rumex crispus) and senna (Cassia spp.). Many of the commercial preparations (patent medicines) based on these plants are readily available. 

Kuzuya H., Tamai I., Beppu H., Shimpo K., Chihara T. Determination of aloenin, barbaloin and isobarbaloin in Aloe species by micellar electrokinetic chromatography. Journal of Chromatography B, 752 91-97 (2001). 

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