Caffeic acid derivatives isolation

There is the often-overlooked group of polyphenols containing the derivatives of hydro-xycinnamic and hydroxybenzoic acids such as caffeic, chlorogenic, and gallic acids (Figure 29.8), which occur in food and exhibit certain antioxidant activity. For example, some caffeic acid esters isolated from propolis from honeybee hives showed antiinflammatory... 

Phytochemistry Flowering plant tops contain 0.01-0.04 % essential oil (similar to Salvia sclarea in composition) with a pleasant aroma. In leaves there were 47 mg% vitamin C, and seeds contained up to 19 % oil (Khalmatov 1964). Triterpenoids, including ursane, oleanane, and lupane derivatives were isolated from the aboveground parts (Savona et al. 1987). The roots were found to contain a number of caffeic acid derivatives (rosmarinic acid, Uthospetmic add B, etc.), diterpenes (royleanone, ferruginol, taxodione, etc.), and the steroid daucosterol (Tezuka et al. 1998). 

The main caffeic acid derivative in the aerial parts of Echinacea purpurea is cichor-ic acid (2R,3R-0-dicaffeoyl-tartaric acid). It was first isolated from the leaves of . purpurea by Becker and Hsieh [83]. Hsieh [106] reported no data on the optical activity of cichoric acid. The cichoric acid isolated later from . purpurea by Remiger [84] and by Soicke et al. [107] had an optical rotation [a] of ca. -370 . In contrast, the cichoric acid first isolated by Scarpati and Oriente [108] from Cichorium intybus displayed a rotation of +383.5 . Cichoric acid from lettuce Lac-tuca sativa) [109] and from endives (Cichorium endivia) [110] was also dextrorotatory. Synthetic studies by Scarpati and Oriente [108] showed that cichoric acid from Cichorium intybus contains a residue of (2S,3S)-(-)-tartaric acid. Conversely, that in... 

Recently, Maruta et al. [112] have found that methanol extracts of roots of burdock show a significant antioxidant activity in an in vitro lipid peroxidation assay, and have isolated five caffeoylquinic acid derivatives (CQAs) from the roots of burdock (Arctium lappa L ), an edible plant in Japan. Antioxidant activities of DCQAs and related compounds have been investigated by measuring the hydroperoxidation of methyl linolate via radical chain reaction. This study indicates that in this particular system caffeic acid and CQAs are more effective than a-tocopherol. These results approximately agree with our findings [38], Additionally, CQAs as the principle antioxidative substance in burdock root have been characterized. 

An optically active dicarboxylic acid lignan (caffeic acid dimer), named epiphyllic acid was isolated from liverwort as well as its derivatives, which do not belong to any typical lignan-producing subgroups. They also occur in some vascular plants, even as a triterpene ester of epiphyllic acid in Rhoipte-lea chiliantha [37]. The conversion of caffeic acid to epiphyllic acid was demonstrated by Tazaki et al. [38]. However, little is known about the biosynthesis of this type of lignan in vascular plants yet. 

A number of putrescine derivatives have been detected in nature for which one or two cinnamic acid analogs with amide linkages are known 4-coumaroylputrescine (2), di-4-coumaroylputrescine (3), feruloylpu-trescine (4) (subaphylline), diferuloylputrescine (5), caffeoylputrescine (6) (paucine), dicaffeoylputrescine (7), sinapoylputrescine (8), and disinapoyl-putrescine (9). Paucine, one of the first diaminoalkane alkaloids known since 1894 as a component of the seed of Pentaclethra macrophylla, was hydrolyzed (40% KOH - H20) to give putrescine and caffeic acid. Structure 6 was deduced (37) from this data together with spectroscopic data, especially mass spectra. Another derivative of putrescine, subaphylline (4), first isolated from Salsola subaphylla, was shown to be the monoferuloyl derivative of putrescine by hydrolysis (30% K0H-H20) (38). The structure elucidation of the other derivatives of putrescine (2, 3, 5, 7-9) mentioned before was undertaken in a manner similar to that of 4 and 6. Several compounds were synthesized and compared to the natural products and are summarized in Table II of Section V. 

The ubiquitous plant compound chlorogenic acid (isolated from green coffee beans) is formed by transesterification with the glycoside cinnamoyl-glucose.187 Coumaroyl-CoA is converted into monomeric and dimeric amides with agmatine, which provides barley plants with resistance to mildew.188 Similar compounds with various polyamines and derived from p-coumaric, caffeic, ferulic, or sinapic acid appear to... 

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