A- -bisabolol

OC-Bisabolol. a-Bisabolol (99) occurs in camomile flowers and has been shown to be the main antiphlogistic and spasmolytic component of the European medicinal plant. The use of bisabolol is recommended mainly for its pharmacodynamic properties in cosmetic preparations for skin protection. 

Bis(4-isocyanatophenyl)methane (MDI), with alkyd resins, 2 164 a-Bisabolol, 24 548... 

Keywords Biodiversity, /-/-a-bisabolol, /-/-a-bisabololoxide A and B, chamazu-lene, chamomile, chemo types, essential oil, sesquiterpenes... 

About 120 chemical constituents have been identified in chamomile as secondary metabolites, including 28 terpenoids, 36 flavonoids and 52 additional compounds [4]. A substantial part of drag effects are determined by the essential oil content. Oil is collected from flower heads, either by steam distillation or solvent extraction, for yields of 0.24-1.90% of fresh or dry plant tissue. Among the essential oil constituents the most active are /-/-a-bisabolol and chamazulene. /-/-a-bisabolol has demonstrated anti-inflammatory, antispasmodic, antimicrobial, antiulcer, sedative and CNS activity. Chamazulene is also anti-inflammatory. Topical applications of chamomile preparation have shown benefit in the treatment of eczema, dermatitis and ulceration [5]. 

Compound identification. Determination of major components of essential oil was realized on the basis of use of standard compounds (/-/-a-bisabolol, chamazu-lene, cis-/trans-en-in-dicycloether and /-/-a-bisabololoxide A and B). Qualitative identification of selected components was carried out by the comparison the retention times of all detected components with retention time of standard compounds. 

The highest contents of /-/-a-bisabololoxide A (39.9 7.5%) and /-/-a-bisabo-loloxide B (9.75 4.20%) are typical for chamomile plants, which flower anthodia were collected in various places in the East-Slovakian Lowland. In regard to following sesquiterpenes, the chamomile anthodia contain /-/-a-bisabolol (5.09 1.55%) and chamazrrlene (7.65 3.90%). 

Flowers have a highest /-/-a-bisabololoxide A content, about 41% (Table 7.2). The pharmaceutically effective components (/-/-a-bisabolol and chamazulene) have a lower representation. 

One from very important exporter in the world of the chamomile flowers is Egypt. The possibility to visit some chamomile production areas in this African country occured several times in 1997 and 1998. Chamomile flowers from different Egyptian areas have a highest /-/-a-bisabololoxide content, from 40.1% to 68.2% (Table 7.4). The pharmaceutically effective components (/-/-a-bisabolol and... 

Table 7.5 The /-/-a- bisabolol chamomile from two European Isles...

Another illustration of the use of such a biocatalytic approach was the synthesis of either enantiomer of a-bisabolol, one of these stereoisomers (out of four) which is of industrial value for the cosmetic industry. This approach was based on the diastereoselective hydrolysis of a mixture of oxirane-diastereoiso-mers obtained from (R)- or (S)-limonene [68]. Thus,starting from (S)-hmonene, the biohydrolysis of the mixture of (4S,81 S)-epoxides led to unreacted (4S,8S)-epoxide and (4S,8i )-diol. The former showed a diastereomeric purity (> 95%) and was chemically transformed into (4S,8S)-a-bisabolol. The formed diol... 

Scheme 15. Chemoenzymatic synthesis of a-bisabolol using fungal epoxide hydrolase...

Bisabolene-type sesquiterpenes, e.g. a-bisabolene 74 (Structure 4.20), are widely distributed in nature. This sesquiterpene hydrocarbon is a constituent of bergamot, myrrh and a wide variety of essential oils. Its oxygenated derivatives a-bisabolol [6-methyl-2-(4-methyl-3-cyclohexen-l-yl)-5-hepten-2-ol] 75 and -bisabolol [4-methyl-l-(6-methylhept-5-en-2-yl)cyclohex-3-enol] 76 are found abundantly in chamomile. 

Matricaria Matricaria recutita L. (-)-a-Bisabolol (10-65) and bis-abolol oxides (29-81) types exist... 

Four stereoisomers of a-bisabolol are possible and also occur in different plants [7, 10]. Synthetic a-bisabolol is not optically active [11]. 

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