Polyphenolic content and physiological activities of Chinese hawthorn extracts.

Hawthorn polyphenol (HP) was prepared by ethyl acetate treatment of the ethanol extract (HE) of Chinese hawthorn fruit. The concentrations of 15 polyphenols in the HP, HE, extraction residue (HJ), and a hawthorn leaf extract (HF) were determined by HPLC. For HP, the total content of the 15 polyphenols was 21.4%, comprised of 19.7% of procyanidins, 1.21% of chlorogenic acid, and 0.48% of flavonoids, compared to 2.55% for the HE. The yields of procyanidin monomer, dimer, trimer, tetramer, and pentamer were 50.5%, 30.3%, 23.0%, 14.6%, and 12.5% respectively, and the mean degree of polymerization was reduced to 1.39 (HP) from 1.65 (HE). Seven different physiological actions of the four extracts were investigated. The HP showed strong O(2)(-) and (.-)OH scavenging capacities (IC(50) values of 6.3 microg/ml and 1.1 microg/ml respectively), as well as selective prolyl endopeptidase inhibition (IC(50) of 60 microg/ml). The active constituents appeared to be procyanidins.

Quantification of the polyphenols and triterpene acids in chinese hawthorn fruit by high-performance liquid chromatography.

The levels of seven polyphenols (epicatechin, procyanidin B2, procyanidin B5, procyanidin C1, hyperoside, isoquercitrin, and chlorogenic acid) and two triterpene acids (oleanolic acid and ursolic acid) in the matured fruits of Chinese hawthorn (Crataegus pinnatifida Bge. var. major N.E.Br.) were determined by high-performance liquid chromatography methods. The average contents of those constituents in 37 representative cultivars were 1405, 1505, 339, 684, 56, 41, 234, 952, and 147 microg/g fresh weight (FW), respectively. A significant inverse correlation between the procyanidin contents and the latitude of the geographical origin of the cultivars was observed (r = 0.3851, P < 0.02). Correlation analysis of the levels of the nine compounds in the 37 cultivars yielded a strong correlation (P < 0.001) between the individual levels of the four procyanidins and the sum of the procyanidins level (r = 0.7413-0.9898) and between the flavonoids and the chlorogenic acid (r = 0.5383-0.9212). The changes in level of the nine compounds in the hawthorn fruit were evaluated during maturation using the Hebei Dajinxing cultivar. Sixty-one days after blossom, the polyphenol level reached the highest point and the sum of the contents was 1.36 g/100 g FW.

Analyses of arbutin and chlorogenic acid, the major phenolic constituents in Oriental pear.

The HPLC retention time, photodiode array UV spectrum analysis, and LC/MS results indicated that arbutin and chlorogenic acid are the main phenolic constituents in Oriental pear. The two compounds exist in different organs of the Yali pear, which is one of the major cultivars of Pyrus bretschnrideri. The contents of arbutin in the leaf bud, floral bud, flower, and young fruit were 11.9, 12.4, 8.29, and 9.92 mg/g fresh weight (FW), respectively. Chlorogenic acid amounts in the same organs were 2.26, 3.22, 5.32, and 3.72 mg/g FW, respectively. During development, the concentration of the two compounds in Yali pears was the greatest in young fruit (9.92 mg/g FW of arbutin and 3.72 mg/g FW of chlorogenic acid), and then declined swiftly with fruit growth to less than 0.400 and 0.226 mg/g FW, respectively, in mature fruit. Large differences existed in the distribution of the two compounds in parts of the mature fruit of 14 Oriental pear cultivars. The greatest concentration of arbutin was found in the peel (1.20 mg/g FW), which was 3-5 times greater than that found in the core and 10-45 times greater than the level in the pulp. The concentration of chlorogenic acid in the core was greater than that in the peel. The compounds in 17 cultivars of Oriental pear, including P. bretschnrideri, Pyrus pyrifolia, Pyrus ussuriensis, and Pyrus sinkiangensis, were compared with those in 5 cultivars of Occidental pear (Pyrus communis). The mean concentration of arbutin in the Oriental pear cultivars was 0.164 mg/g FW, greater than the 0.083 mg/g FW found in the Occidental pear cultivars. The greatest arbutin content was 0.400 mg/g FW, found in the Yali pear. However, the mean concentration of chlorogenic acid in the Oriental pear was 0.163 mg/g FW, less than that found in the Occidental pear (0.309 mg/g FW).

High-performance liquid chromatographic determination of phenolic compounds in rice.

A method has been developed for the determination of 6'-O-feruloylsucrose, 6'-O-sinapoylsucrose, ferulic acid, sinapinic acid, p-coumaric acid, chlorogenic (3-caffeoylquinic) acid, caffeic acid, protocatechuic acid, hydroxybenzoic acid, vanillic acid, and syringic acid in rice. The rice samples were extracted with 70% ethanol, filtered, and defatted. The defatted aqueous solution was subjected to solid-phase extraction using a C18 silica gel cartridge; no analyte was lost in this procedure. The 70% acidic methanol elution was analyzed directly by HPLC and HPLC-ESI-MS. Phenolic compounds were separated with a C18 reversed-phase column by gradient elution using 0.025% trifluoroacetic acid in purified water (A)--acetonitrile (B) (0 min, 5% B; 5 min, 9% B; 15 min, 9% B; 22 min, 11% B; and 38 min, 18% B) as the mobile phase at a flow rate of 0.8 ml/min. Detection limits ranged from 0.10 to 0.35 ng per injection (5 microl). Relative standard deviations of 0.22-3.95% and recoveries of 99-108% were obtained for simultaneous determination of these phenolic compounds. This method was applied to analysis of phenolic compounds in brown rice and germinated brown rice soaked in 32 degrees C water for varying durations.

Analysis of phenolic compounds in white rice, brown rice, and germinated brown rice.

Two hydroxycinnamate sucrose esters, 6'-O-(E)-feruloylsucrose and 6'-O-(E)-sinapoylsucrose, were isolated from methanol extracts of rice bran. Soluble and insoluble phenolic compounds as well as 6'-O-(E)-feruloylsucrose and 6'-O-(E)-sinapoylsucrose from white rice, brown rice, and germinated brown rice were analyzed using HPLC. The results demonstrated that the content of insoluble phenolic compounds was significantly higher than that of soluble phenolics in rice, whereas almost all compounds identified in germinated brown rice and brown rice were more abundant than those in white rice. 6'-O-(E)-Feruloylsucrose (1.09 mg/100 g of flour) and 6'-O-(E)-sinapoylsucrose (0.41 mg/100 g of flour) were found to be the major soluble phenolic compounds in brown rice. During germination, an approximately 70% decrease was observed in the content of the two hydroxycinnamate sucrose esters, whereas free phenolic acid content increased significantly; the ferulic acid content of brown rice (0.32 mg/100 g of flour) increased to 0.48 mg/100 g of flour and became the most abundant phenolic compound in germinated brown rice. The content of sinapinic acid increased to 0.21 mg/100 g of flour, which is nearly 10 times as much as that in brown rice (0.02 mg/100 g of flour). In addition, the total content of insoluble phenolic compounds increased from 18.47 mg/100 g of flour in brown rice to 24.78 mg/100 g of flour in germinated brown rice. These data suggest that appropriate germination of brown rice may be a method to improve health-related benefits.