Matricaria genus as a source of antimicrobial agents: From farm to pharmacy and food applications

Nutritious foods have to contain trace constituents such as minerals, vitamins and flavors. The role of flavors is critical; they are partially responsible for the digestion of food in man and control food recognition, selection and acceptance. Flavor can be considered to be the neuro- physiological answer to the question simultaneously asked of the chemical senses of taste and odor by the stimulus, food (447).

Recent Developments in the Field of Naturally-Occurring Aroma Components

Matricaria recutita, once it has been called as Marticaria chamomilla, Chamomilla recutita, and Chamomilum nobile family Asteraceae. The main constituents of this plant include the terpenoids α-bisabolol and its oxides and azulenes, including chamazulene. Matricaria recutita shows different pharmacological activities like anti-inflammatory, anti- cancer, treatment of stress and depression, anti-allergic etc. This review focuses on the detailed chemical constituents, pharmacological activities of different parts of this plant.

Pharmacological potential of matricaria recutita-a review

Although epoxy-n-alkanes can be produced from the corresponding alkene by microorganisms only if they were grown on hydrocarbons, the terminal double bond of acyclic terpenoids can be oxidized by some glucose using strains in high optical yields. While most fungi possess hydrolases which open the epoxides to diols with e.e. of 95–98% we found some microorganisms which did not affect the epoxide. Alcohols like linalool or nerolidol reacted intramolecularly with the oxiran moiety to yield tetrahydrofurans and tetrahydropyrans. The absolute configuration of the epoxide is usually S but depends on the strain for its optical purity. The configuration of the epoxides were independent of the absolute configuation of the substrate.

Chiral Intermediates by Microbial Epoxidations

Plant peroxygenase (PXG) oxidizes unsaturated fatty acids by transferring an oxygen atom of a hydroperoxide to the double bond, thereby providing epoxides. In this work we investigated the potential of a PXG from tomato (Solanum lycopersicum, SlPXG) to catalyze the oxidation of a variety of natural products. A SlPXG gene was cloned from tomato, heterologously expressed in yeast and the membrane bound recombinant SlPXG protein was used as enzyme source. Unsaturated fatty acids, fatty acid derivatives, and terpenes were epoxidized by SlPXG in the presence of various hydroperoxides exclusively at their cis-double bonds. Terpenes with p-menthene skeleton were transformed in different ways depending on their molecular structures. R-(+)- and S-(−)-limonene were converted to R-(+)-limonene-trans-1,2-epoxide (97%) and cis-S-(−)-limonene-1,2-epoxide (88%), respectively whereas α-terpinene was hydroxylated to cis-1,4-dihydroxy-p-menth-2-ene and γ-terpinene was aromatized to p-cymene. In the last reaction the hydroperoxide served as hydrogen acceptor rather than an oxygen donor. PXG appears to be a versatile biocatalyst able to perform different kinds of oxidation reactions. As no cofactors like NAD(P)H are required and H2O2 is an environmentally friendly oxidant, PXG enables new applications for the synthesis of fine chemicals from renewable resources.

Epoxidation, hydroxylation and aromatization is catalyzed by a peroxygenase from Solanum lycopersicum

Bei der Isolierung der beiden flussigen (−)-α-Bisabololoxide A und B (2 und 5) konnte in geringer Menge eine kristalline Substanz C15H26O2 vom Schmp. 99–100° aus Athanol isoliert und als ein drittes α-Bisabololoxid ((−)-α-Bisabololoxid C) aufgeklart werden. Die Struktur 6 wurde vorwiegend mit spektrometrischen Methoden (NMR- und Massenspektren) und in Kombination mit der Gas-Flussig-Chromatographie (GLC-MS) ermittelt. Unter den gleichen Bedingungen wurden die beiden (−)-α-bisabololoxide A und B erneut einer kritischen Strukturanalyse unterworfen und die Formeln 2 und 5 bestatigt.



Structure of a Third Bisabololoxide from Matricaria Chamomilla L.



During the isolation of the liquid (−)-α-bisabololoxides A and B (2 and 5) a small amount of a crystalline substance with m.p. 99–100° was separated and identified as a third (−)-α-bisabololoxide. The structure of this new bisabololoxide C was elucidated with NMR- and mass spectra and in combination with GLC-MS, further on the basis of chemical evidence. Using the same methods the (−)-α-bisabololoxides A and B have been again investigated and structures, 2 and 5 were confirmed.

Vlastimil Herout

Papers

Strukturaufklärung eines dritten Bisabololoxides aus Matricaria Chamomilla L. und massenspektrometrischer Vergleich der Bisabololoxide A, B und C