Nadia M. Sokkar

A Profile of Bioactive Compounds of Rumex vesicarius L.

The present study was designed to investigate the bioactive compounds in extracts of Rumex vesicarius L. (Polygonaceae), a wild edible herb growing in Egypt. Ethyl acetate and n-butanol fractions of leaves of R. vesicarius were conducted by HPLC-PDA-MS/MS-ESI in the negative mode to analyze phenolics content. Results revealed the identification of 13 phenolic compounds: 8-C-glucosyl-apigenin, 8-C-glucosyl-luteolin, 6-C-hexosyl-quercetin, 3-O-rutinosyl-quercetin, 7-O-rhamno-hexosyl-diosmetin, 7-O-rhamno-acetylhexosyl-diosmetin, catechin, epicatechin, ferulohexoside, 6-C-glucosyl-naringenin, epicatechin gallate, 6-C-glucosyl-catechin, and epigallocatechin gallate. Quantification of the identified compounds revealed that 6-C-glucosyl-naringenin was the major compound. Also, qualitative and quantitative analysis of the hydro-ethanolic extract of leaves was carried out for ascorbic acid, α-tocopherol, β-carotene. The essential oil as well as lipids analysis of saponifiable and unsaponifiable matters. The biochemical studies were conducted to evaluate the antioxidant and hepatoprotective potential of roots (REE), leaves (LEE), and fruits (FEE) ethanolic extracts of R. vesicarius (100 mg/kg b.wt., p.o., each) against hepatotoxicity induced by CCl(4) (0.5 mL/kg b.wt., p.o., 3 times a week) compared with silymarin (50 mg/kg b.wt., p.o.) as standard drug. The results confirmed that coadministration of the tested extracts or silymarin with CCl(4) for 4 wk exhibited a marked hepatoprotective activity, attributed to their antioxidant potential, membrane stabilizing effect, and antifibrogenic activities. Practical Application:  Investigation of the effect of hommad as a safe hepatoprotective diet that prospectively directs the attention to a valuable therapeutic natural herb rich in bioactive constituents.

A New Flavonoid C-Glycoside from Celtis australis L. and Celtis occidentalis L. Leaves and Potential Antioxidant and Cytotoxic Activities

A major development over the past two decades has been the realization that free radical induced lipid peroxidation and DNA damage are associated with major health problems, e.g. cancer and ageing. Plant-derived antioxidants are increasingly found beneficial in protecting against these diseases. Celtis australis L. and Celtis occidentalis L. are two plants that have a variety of uses in folk medicine but have not been evaluated before for their antioxidant and cytotoxic properties. Therefore, the extracts of both plants’ leaves were investigated for these activities, as well as isolation of the bioactive compounds responsible for the activities. Molecular structures of the compounds were elucidated by UV, HRESIMS, 1D (1H and 13C) and 2D (1H-13C HSQC and 1H-13C HMBC) NMR analyses. The ethanolic and aqueous extracts, n-butanol fractions and the isolated major compound were tested for their antioxidant activity using DPPH radical scavenging assay, xanthine oxidase-induced generation of superoxide radical and lipid peroxidation assay by thiobarbituric acid-reactive substances (TBARS) method using rat tissue homogenates. Cytotoxic activities were studied using standard MTT assay. A novel flavonoid C-triglycoside, 4‴-α-rhamnopyranosyl-2″-O-β-d-galactopyranosylvitexin, was isolated from both plants’ leaves, together with seven known flavonoids. The n-butanol fractions and the major compound 2″-O-β-galactopyranosylvitexin showed significant antioxidant activities, more pronounced than the tested standards BHT and dl-α-tocopherol in most tests. All extracts showed variable cytotoxic activities. This study provides strong evidence for the antioxidant and cytotoxic activities of the extracts of Celtis australis L. and Celtis occidentalis L. leaves, which were attributed to the polar n-butanol fractions and the major isolated flavonoid 2″-galactosylvitexin.

Determination of flavonoids in stamen, gynoecium, and petals of Magnolia grandiflora L. and their associated antioxidant and hepatoprotection activities

Chromatographic analysis of flavonoids in ethyl acetate fractions of the stamen, gynoecium, and petal of Magnolia grandiflora L. by HPLC-PDA-MS/MS-ESI in the negative ionization mode was performed in this study. The results revealed the presence of eight flavonoids: apigenin 8-C-glucoside, luteolin 8-C-glucoside, quercetin 3-O-rutinoside, quercetin 3-O-galactoside, quercetin, 3-O-glucoside, kaempferol 3-O-rutinoside, isorhamnetin 3-O-glucoside, and isorhamnetin. Their quantification revealed that luteolin 8-C-glucoside is the major flavonoid and that the total phenolic content is concentrated primarily in the stamen. The antioxidant and hepatoprotective effects of ethanolic extract of the flower organs were evaluated against hepatotoxicity induced by CCl4, compared with the effects of silymarin.

THE PHENOLIC COMPOSITION OF THE HEPATOPROTECTIVE AND ANTIOXIDANT FRACTIONS OF Albizia lebbeck L.

An investigation of the hepatoprotective and antioxidant activities of the chloroform, ethyl acetate and n-butanol fractions of the leaves of Albizia lebbeck L. was performed. The first two fractions expressed the best results regarding the suppression of the increased levels of plasma amino-transferases and alkaline phosphatase in liver-damaged mice (after intoxication with CCl4) compared with silymarin and the significantly increased GSH content of alloxan- induced diabetic rats compared with vitamin E (tests and reference drugs were orally administered). The bioactive fractions of Albizia lebbeck L. were subjected to chromatographic analysis to investigate their phenolic contents using a HPLC-PDA-ESI-MS/MS technique in the negative ion mode. The results constitute the first report of the presence of seven compounds in the genus Albizia, three of which were identified as 3-O-caffeoylquinic acid, cafeic acid, myricetin; four other flavonoids (in mg 100 g-1 dry powder ± SD), myricetin 3-O-rhamnoside (0.129 ± 0.0052), quercetin 3-O-dideoxypentoside (0.011 ± 0.001), kaempferol 3-O-glucoside (0.015 ± 0.002), quercetin 3-O-dihexoside (0.138 ± 0.002); quercetin 3-O-rutinoside at a level of 0.135 ± 0.004; and the aglycones quercetin, luteolin and kaempferol. Method validation was performed, providing an analytical technique that can be used to detect trace amounts of the identified compounds in Albizia extracts with rapid sample preparation.