Mansour Sobeh

Hepatoprotective and hypoglycemic effects of a tannin rich extract from Ximenia americana var. caffra root

BACKGROUND Liver diseases and diabetes are serious health disorders associated with oxidative stress and ageing. Some plant polyphenols can lower the risk of these diseases. PURPOSE We investigated the phytochemical profiling of a root extract from Ximenia americana var. caffra using HPLC-PDA-ESI-MS/MS. The antioxidant activities in vitro were investigated. The hepatoprotective activities were studied in rat models with d-galactosamine (d-GaIN)-induced hepatotoxicity and the antidiabetic activities in STZ-diabetic rats were also investigated. MATERIALS AND METHODS HPLC-PDA-ESI-MS/MS was used to identify plant phenolics. The antioxidant activities in vitro were determined using DPPH and FRAP assays. The in vivo hepatoprotective activities were determined for d-GaIN-induced hepatotoxicity in rats. We determined the liver markers alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), liver peroxidation product malondialdehyde (MDA), glutathione content (GSH), albumin and total bilirubin concentration. The histopathological changes in rat liver were also studied. The antidiabetic activities were also investigated in STZ-diabetic rats and serum glucose, serum insulin hormone, and lipid peroxides were determined. RESULTS The root extract is rich in tannins with 20 compounds including a series of stereoisomers of (epi)catechin, (epi)catechin-(epi)catechin, (epi)catechin-(epi)catechin-(epi)catechin, and their galloyl esters. Promising antioxidant potential was observed in vitro in DPPH assay with EC50 of 6.5 µg extract / 26 µg raw material and in FRAP assay with 19.54 mM FeSO4 compared with ascorbic acid (EC50 of 2.92 µg/ml) and quercetin (FeSO4 24.04 mM/mg), respectively. Significant reduction of serologic enzymatic markers and hepatic oxidative stress markers such as ALT, AST, MDA, GGT, and total bilirubin, as well as elevation of GSH and albumin were observed in rats with d-galactosamine-induced liver damage treated with the extract. These findings agree with a histopathological examination suggesting a hepatoprotective potential for the root extract. The root extract can mediate an antidiabetic effect by reducing elevated blood glucose and serum lipid peroxides levels and by increasing insulin in STZ-diabetic rats by -107, -31.1, +11.3%, respectively. CONCLUSIONS The results of this study suggest that the tannin-rich extract from Ximenia americana var. caffra could be an interesting candidate for the treatment of several health disorders associated with oxidative stress such as hepatocellular injury and diabetes.

Antihyperglycaemic activity of the methanol extract from leaves of Eremophila maculata (Scrophulariaceae) in streptozotocin‐induced diabetic rats

This study was designed to evaluate the antihyperglycaemic activity of the methanol leaf extract of Eremophila maculata (EMM) both in vitro and in vivo.

Identification of phenolic secondary metabolites from Schotia brachypetala Sond. (Fabaceae) and demonstration of their antioxidant activities in Caenorhabditis elegans

Background Schotia brachypetala Sond. (Fabaceae) is an endemic tree of Southern Africa whose phytochemistry and pharmacology were slightly studied. The present work aimed at profiling the major phenolics compounds present in the hydro-alcohol extract from S. brachypetala leaves (SBE) using LC/HRESI/MS/MS and NMR and prove their antioxidant capabilities using novel methods. Methods In vitro assays; DPPH, TEAC persulfate decolorizing kinetic and FRAP assays, and in vivo assays: Caenorhabditis elegans strains maintenance, Intracellular ROS in C. elegans, Survival assay, GFP expression and Subcellular DAF-16 localization were employed to evaluate the antioxidant activity. Results More than forty polyphenols, including flavonoid glycosides, galloylated flavonoid glycosides, isoflavones, dihydrochalcones, procyanidins, anthocyanins, hydroxy benzoic acid derivatives, hydrolysable tannins, and traces of methylated and acetylated flavonoid derivatives were identified. Three compounds were isolated and identified from the genus Schotia for the first time, namely gallic acid, myricetin-3-O-α-L-1C4-rhamnoside and quercetin-3-O-L-1C4-rhamnoside. The total phenolics content of SBE was (376 mg CAE/g), followed by flavonoids (67.87 QE/g). In vitro antioxidant activity of SBE was evidenced by DPPH radical scavenging activity (IC50 of 9 µg/mL), FRAP ferric reducing activity (5,000 mol Fe2+ E/mg) and ABTS peroxide inhibiting activity (1,054 mM Trolox E/mg). The tested extract was able to protect the worms against juglone induced oxidative stress, an increased survival rate (up to 41%) was recorded, when compared with the control group (11%) and attenuate the reactive oxygen species (ROS) accumulation in dose-dependent and reached up to 72% for the highest tested concentration. SBE was also able to attenuate the levels of heat shock protein (HSP) expression in dose-dependent up to 60% in the 150 µg SBE/mL group. In DAF-16 Subcellular localization SBE treated worms showed nuclear localization pattern up to 78%, while it was only 5% in the untreated control group. Discussion A pronounced antioxidant activity in vivo, which can be attributed to its ability to promote the nuclear translocation of DAF-16/FOXO, the main transcription factor regulating the expression of stress response genes. The remarkable antioxidant activity in vitro and in vivo correlates to SBE rich phenolic profile.

Chemical profiling of Phlomis thapsoides (Lamiaceae) and in vitro testing of its biological activities

A phytochemical study of Phlomis thapsoides (Lamiaceae) resulted in the isolation of one new compound, 6,10,17-trimethyl-2-octadecanone, and three known compounds (sitosterol-3-O-β-glucoside, and the iridoid glucosides ipolamiide and lamiide). The structures of the isolated compounds were elucidated using mass spectrometry, 1D/2D NMR spectroscopy experiments in comparison with published data. The chemical composition of the essential oil obtained from aerial parts of P. thapsoides was determined by gas liquid chromatography and gas liquid chromatography-mass spectroscopy. The main volatile constituents were phenylethyl alcohol (6.81 %), trans-3-hexenol (5.55 %), 1-octen-3-ol (5.10 %), α-cadinol (4.92 %), and α-muurolol (4.67 %). The antioxidant activity of the extracts was evaluated by three methods: 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, 2,2′-azinobis-[3-ethylbenzthiazoline-6-sulfonic acid] and ferric reducing antioxidant power assay along with the determination of total phenolic content. Although the ethyl acetate extract contained 362.06 mg of gallic acid equivalents, the antioxidant activities, as revealed by 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis-[3-ethylbenzthiazoline-6-sulfonic acid] and ferric reducing antioxidant power assays, were of medium strength (IC50 of 73.08 ± 3.18, 9.48 ± 0.71 µg/mL and 9.33 ± 0.17 mM of FeSO4 equivalents, respectively). Only lamiide inhibited soybean 5-lipoxygenase with an IC50 value of 72.92 µg/mL in vitro. In-silico molecular modeling studies on 5-lipoxygenase and human 5-lipoxygenase-activating protein were used to evaluate the potential anti-inflammatory activity. Sitosterol-3-O-β-glucoside followed by the iridoid glucoside lamiide exhibited the highest inhibition of 5-lipoxygenase whereas the new compound 6,10,17-trimethyl-2-octadecanone and sitosterol-3-O-β-glucoside exhibited the highest inhibition of 5-lipoxygenase-activating protein as evidenced from their higher fitting scores. The cytotoxicity of the plant extracts and lamiide against Caco2 and HepG-2 cancer cells resulted in IC50 values of >100 µg/mL indicating a low cytotoxicity.

Chemical composition and biological activity of the essential oil from Thymus lanceolatus.

Abstract Thymus lanceolatus is a rare species, which grows wild in Algeria and Tunis. It is used traditionally as a drink and to flavor and preserve meat and poultry. The composition of the essential oil was determined by GLC/FID and GLC/MS. Forty-nine components were identified and quantified, accounting for 96.75% of the total detected components in the oil. The oxygenated monoterpenes (74.85%) constitute the major class of volatile secondary metabolites in the oil. Thymol was the most abundant constituent (69.61%) followed by γ-terpinene (8.38%). The antioxidant activity was evaluated using both diphenylpicrylhydrazyl (DPPH˙) reduction and 2-deoxyribose (2-DR) degradation prevention methods. The oil showed a very potent antioxidant activity with IC50 values of 0.20 ± 0.07 and 4.96 ± 0.39 μg/mL for the DPPH˙ and 2-DR methods, respectively. The antimicrobial activity of the oil was assessed using the agar diffusion method, and the in vitro cytotoxicity on five different cancer cells was examined using the MTT assay. The oil revealed promising inhibitory activity against Gram positive bacteria, especially Bacillus subtilis and Streptococcus pyogenes with an MIC value of 62.5 μg/mL. Additionally, the highest cytotoxic activity was observed against the HL-60 cells with an IC50 of 113.5 μg/mL. These results validate some of their traditional uses in food preservation.

HPLC‐DAD‐ESI‐MS/MS analysis of fruits from Firmiana simplex (L.) and evaluation of their antioxidant and antigenotoxic properties

The secondary metabolites of the fruits of Firmiana simplex (L.) were analysed by LC‐DAD‐ESI‐MS/MS; furthermore, we evaluated their antioxidant and antigenotoxic properties.

Albizia harveyi: phytochemical profiling, antioxidant, antidiabetic and hepatoprotective activities of the bark extract

Profiling the polyphenols in the methanol extract from the bark of Albizia harveyi was performed by HPLC–PDA–ESI–MS/MS analysis. The phytochemical analysis identified 39 compounds, the majority of them were flavan-3-ol derivatives and condensed tannins. Total phenolic content, determined by the Folin–Ciocalteu method amounted to 489 mg gallic acid equivalents/g extract. The extract showed promising antioxidant activities with an EC50 of 3.6 µg/mL and 18.32 mM FeSO4 equivalent/mg extract in radical scavenging assay and ferric reducing antioxidant power assays, respectively. The hepatoprotective potential of the extract in rats was determined in vivo in a d-galactosamine-induced liver toxicity model. A dose of 100 mg/kg (body weight) of the bark extract reduced levels of aspartate aminotransferase, gamma-glutamyltransferase and total bilirubin by 35.7, 65.3, and 23.8% (p < 0.05), respectively whereas glutathione was increased by 59.1%. These effects were similar to silymarin which was used as positive control. The extract (100 mg/kg (body weight) mediated a substantial antidiabetic response in streptozotocin-induced diabetic rats manifested by a significant reduction in serum glucose and lipid peroxides and significant increase of serum insulin. Docking of d-(+) catechin and the dimer (epi)catechin-(epi)catechin into the active site of the enzymes human pancreatic α-amylase, maltase-glucoamylase, and aldol reductase revealed that these enzymes may be possible targets via which, the studied Albizia harveyi extract could exert its antidiabetic effect.

Chemical Profiling of the Essential Oils of Syzygium aqueum, Syzygium samarangense and Eugenia uniflora and Their Discrimination Using Chemometric Analysis.

The essential oil compositions of the leaves of three related Myrtaceae species, namely Syzygium aqueum, Syzygium samarangense and Eugenia uniflora, were investigated using GLC/MS and GLC/FID. Altogether, 125 compounds were identified: α‐Selinene (13.85%), β‐caryophyllene (12.72%) and β‐selinene constitute the most abundant constituents in S. aqueum. Germacrene D (21.62%) represents the major compound in S. samarangense whereas in E. uniflora, spathulenol (15.80%) represents the predominant component. Multivariate chemometric analyses were used to discriminate the essential oils using hierarchical cluster analysis (HCA) and principal component analysis (PCA) based on the chromatographic results. The antimicrobial activity of the popularly used E. uniflora essential oil was assessed using broth microdilution method against six Gram‐positive, three Gram‐negative bacteria and two fungi. The oil showed moderate antimicrobial activity against Bacillus licheniformis exhibiting MIC and MMC of 0.63 mg/ml. The cytotoxic activity of E. uniflora essential oil was investigated against Trypanosoma brucei brucei (T. b. brucei) and MCF‐7 cancer cell line using MTT assay. It showed moderate activity against MCF‐7 cells with an IC50 value of 76.40 μg/ml. On the other hand, T. brucei was highly susceptible to E. uniflora essential oil with IC50 of 11.20 μg/ml, and a selectivity index of 6.82.

A proanthocyanidin-rich extract from Cassia abbreviata exhibits antioxidant and hepatoprotective activities in vivo

ETHNOPHARMACOLOGICAL RELEVANCE Cassia abbreviata is a small to medium sized branched umbrella-shaped deciduous tree. It is widely spread in the tropics, especially in Africa, having a long history in traditional medicine for the treatment of numerous conditions such as headaches, diarrhea, constipation, some skin diseases, malaria, syphilis, pneumonia, stomach troubles, uterine pains, and against gonorrhea. AIM OF THE STUDY We investigated the phytochemical constituents of a root extract from Cassia abbreviata using HPLC-PDA-ESI-MS/MS. We also determined the antioxidant activities in vitro and in vivo using the nematode Caenorhabditis elegans as a model organism. The hepatoprotective activities in case of D-galactosamine (D-GaIN)-induced hepatotoxicity were studied in a rat model. MATERIALS AND METHODS HPLC-PDA-ESI-MS/MS analysis allowed the identification of the secondary metabolites of the methanol extract. DPPH and FRAP assays were used to determine the antioxidant activities in vitro. Using the C. elegans model, survival rates under juglone induced oxidative stress, intracellular ROS content, quantification of Phsp-16.2: GFP expression and subcellular DAF-16: GFP localization were investigated to determine the antioxidant activities in vivo. The in vivo hepatoprotective potential of the root extract was evaluated for D-galactosamine (D-GaIN)-induced hepatotoxicity in rats. The activity of the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), in addition to liver peroxidation product malondialdehyde (MDA) and glutathione content (GSH), as well as albumin and total bilirubin concentration, were determined. A histopathological study was also performed. RESULTS AND CONCLUSIONS C. abbreviata root extract is rich in polyphenolics, particularly proanthocyanidins. HPLC-PDA-ESI-MS/MS analysis resulted in the identification of 57 compounds on the bases of their mass spectra. (epi)-Catechin, (epi)-afzelechin, (epi)-guibourtinidol, and (ent)-cassiaflavan monomers as well as their dimers, trimers, and their diastereomers are the main components of the extract. The total phenolic content amounted for 474mg/g root extract expressed as gallic acid equivalent using the Folin-Ciocalteu method. The extract exhibited powerful antioxidant activity with EC50 of 6.3μg/mL in DPPH and 19.15mM FeSO4 equivalent/mg sample in FRAP assay. In C. elegans model, the extract (200μg/mL) was able to increase the survival rate by 44.56% and reduced the ROS level to 61.73%, compared to control group. Pretreatment of rats with 100mg extract/kg (b. wt.) reduced MDA by 47.36% and elevated GSH by 59.1%. The extract caused a significant reduction of ALT, AST and GGT activities by 11%, 35.7% and 65%, respectively. The findings of this study suggest that the proanthocyanidin-rich extract from C. abbreviata may be an interesting candidate for hepatoprotective activity in case of hepatocellular injury.

Senna singueana: Antioxidant, Hepatoprotective, Antiapoptotic Properties and Phytochemical Profiling of a Methanol Bark Extract

Natural products are considered as an important source for the discovery of new drugs to treat aging-related degenerative diseases and liver injury. The present study profiled the chemical constituents of a methanol extract from Senna singueana bark using HPLC-PDA-ESI-MS/MS and 36 secondary metabolites were identified. Proanthocyanidins dominated the extract. Monomers, dimers, trimers of (epi)catechin, (epi)gallocatechin, (epi)guibourtinidol, (ent)cassiaflavan, and (epi)afzelechin represented the major constituents. The extract demonstrated notable antioxidant activities in vitro: In DPPH (EC50 of 20.8 µg/mL), FRAP (18.16 mM FeSO4/mg extract) assays, and total phenolic content amounted 474 mg gallic acid equivalent (GAE)/g extract determined with the Folin-Ciocalteu method. Also, in an in vivo model, the extract increased the survival rate of Caenorhabditis elegans worms pretreated with the pro-oxidant juglone from 43 to 64%, decreased intracellular ROS inside the wild-type nematodes by 47.90%, and induced nuclear translocation of the transcription factor DAF-16 in the transgenic strain TJ356. Additionally, the extract showed a remarkable hepatoprotective activity against d-galactosamine (d-GalN) induced hepatic injury in rats. It significantly reduced elevated AST (aspartate aminotransferase), and total bilirubin. Moreover, the extract induced a strong cytoplasmic Bcl-2 expression indicating suppression of apoptosis. In conclusion, the bark extract of S. sengueana represents an interesting candidate for further research in antioxidants and liver protection.