Hanan M. Al-Yousef

Vitamin E protects the brain against oxidative injury stimulated by excessive aluminum intake.

The effect of feeding groups of mice with a diet containing 2000, 4000 and 6000 μg aluminum (Al3+/g) for two weeks (subacute) or 2000 and 4000 μg Al3+/g for eight weeks (subchronic) as well as the coadministration of vitamin E (α‐tocopherol) 500 μg/g with Al3+, on the status of glutathione (GSH) and lipid peroxides as thiobarbituric acid reactive substances (TBARS) in whole brain tissues were evaluated. Changes in TBARS were further evaluated in vitro following the incubation of brain homogenates of the Al3+‐fed mice in the presence of 50 μM FeSO4. The results of subacute experiments revealed that the brain levels of GSH were significantly decreased only in the group of mice that received 6000 μg Al3+/g diet (P<0.05) and this effect was partially ameliorated when vitamin E was coadministered with Al3+. TBARS were significantly increased in vitro only in the presence of free iron ions and depended on the concentration of Al3+ in the diet. The effect was opposed by the vitamin E intake.

Proanthocyanidin-Rich Date Seed Extract Protects Against Chemically Induced Hepatorenal Toxicity

A hydroacetone extract was prepared from seeds of Phoenix dactylifera L. var. Khalas, which is an industrial by-product of date processing. The proanthocyanidin nature of the extract (coded as DTX) was characterized by phytochemical and nuclear magnetic resonance (NMR) analyses. The total phenol/proanthocyanidin content and antioxidant activity of DTX were estimated by Folin-Ciocalteu, vanillin-sulfuric acid, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, respectively. The hepatorenal protective activity of DTX was evaluated using CCl4-induced toxicity model in rats, in comparison with silymarin (SYL). Results of the histopathological examination and measurements of various hepatorenal serum indices and tissue biochemical markers demonstrated that DTX displayed marked protective potential against CCl4-induced liver and kidney injury at 100 mg/kg/rat. Relative to the control CCl4-intoxicated group, pretreatment with DTX significantly (P<.001) suppressed the elevated serum levels of alanine aminotransferase and aspartate aminotransferase (ALT and AST), alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), bilirubin, creatinine, and calcium, whereas it significantly (P<.001) increased the diminished serum levels of high-density lipoprotein cholesterol (HDL-C) and total protein (TP). Moreover, DTX significantly decreased malondialdehyde (MDA) formation and increased TP synthesis in hepatorenal tissues compared with the intoxicated control. The improvement in biochemical parameters by DTX was observed in a dose-dependent manner and confirmed by restoration of normal histological features. The acute toxicity test of DTX in rats revealed safety of the extract. This study reveals that DTX enhances the recovery from xenobiotics-induced toxicity initiated by free radicals.

Hepatorenal protective effect of Antistax ® against chemically-induced toxicity

Background: Antioxidant natural products and chemoprevention are considered nowadays as an effective approach against health various disorders and diseases induced by oxidative stress or free radicals. Objective: The aim of this study was to assess the hepato- and nephroprotective activity of a standardized red vine leaf aqueous extract AS195 (Antistax®). Methods: The protective activity of AS195 (100 mg/kg) was investigated on carbon tetrachloride (CCl4)-intoxicated rats in comparison with silymarin. The flavonoid/proanthocyanidin nature of AS195 was identified by phytochemical and nuclear magnetic resonance (NMR) analyses, while its total phenol/proanthocyanidin/flavonoid content and antioxidant activity were determined by Folin-Ciocalteau, vanillin-sulfuric acid, AlCl3, and 2, 2-diphenyl-2-picrylhydrazyl radical scavenging assays, respectively. Results: Relative to the control CCl4 –intoxicated group, pretreatment with AS195 could significantly suppressed the elevated serum levels of alanine aminotransferase, alkaline phosphatase, γ-glutamyl transferase, total cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, triglycerides, bilirubin, creatinine, uric acid, and calcium, whereas it significantly increased the diminished serum levels of high-density lipoprotein cholesterol, albumin and total protein. Moreover, AS195 significantly decreased malondialdehyde formation in the tissues of liver and kidney, whereas it significantly elevated and nonprotein sulfhydryl groups, compared with the intoxicated control. The improvement in biochemical parameters by AS195 was obviously observed and further confirmed by restoration of normal histological features in the two organs. Conclusions: The results of the present study revealed the capacity of AS195 to enhance the recovery from xenobiotic-induced hepatorenal toxicity initiated by free radicals.

Concurrent analysis of bioactive triterpenes oleanolic acid and β-amyrin in antioxidant active fractions of Hibiscus calyphyllus, Hibiscus deflersii and Hibiscus micranthus grown in Saudi Arabia by applying validated HPTLC method

In this study, we developed a validated HPTLC method for concurrent analysis of two natural antioxidant triterpenes, oleanolic acid (OA) and β-amyrin (BA) in the biologically active fractions (petroleum ether, toluene, chloroform, ethyl acetate and n-butanol) of aerial parts of three Hibiscus species (H. calyphyllus, H. deflersii and H. micranthus). The chromatography was conducted on normal HPTLC (ready to use glass-plate coated with silica gel 60 F254) plate with chloroform and methanol (97:3, V/V) used as mobile phase. The derivatization of the developed plate was done with p-anisaldehyde and scanned at λmax = 575 nm. Well resolved and intense peaks of OA and BA were obtained at Rf = 0.36 and 0.57, respectively. The linear regression equation/correlation coefficient (r2) for OA and BA were Y = 6.65x + 553.35/0.994 and Y = 9.177x + 637.23/0.998, respectively in the linearity range of 100–1200 ng/spot indicated good linear relationship. The low values of %RSD for intra-day/inter-day precision of OA (1.45–1.61/1.38–1.59) and BA (1.52–1.57/1.50–1.53) suggested that the method was precise. The recovery/RSD (%) values for OA and BA were found to be 99.21–99.62/1.39–1.95 and 98.75–99.70/1.56–1.80, respectively assures the reasonably good accuracy of the proposed method. Fifteen samples were analyzed to check the content of OA and BA by using the developed HPTLC methods. The content of OA in different samples were found to be 3.87 (HmP) > 1.212 (HcP) > 0.673 (HdC) > 0.493 (HdP) > 0.168 (HdE) > 0.059 (HcC) > 0.015 (HcE) > 0.008 (HmT) µg/mg of the dried weight of extract. However the content of BA was found as: 2.293 (HmP) > 1.852 (HdT) > 0.345 (HdC) > 0.172 (HmT) > 0.041 (HdE) > 0.008 (HcC) µg/mg of the dried weight of extract. Some Hibiscus species fractions exhibited good antioxidant potential like: HcE (IC50 = 17.6 ± 1.8) > HdB (IC50 = 32.16 ± 0.9) > HmP (IC50 = 80.4 ± 4.5) > HmT (IC50 = 99.7 ± 8.2) when compared with ascorbic acid (IC50 = 14.2 ± 0.5), while other fractions exhibited only mild antioxidant capability. The developed HPTLC method can be further exploited for analysis of these markers in the quality assessment of raw material as well as herbal formulations available in the market.

Onion Peel Ethylacetate Fraction and Its Derived Constituent Quercetin 4′-O-β-D Glucopyranoside Attenuates Quorum Sensing Regulated Virulence and Biofilm Formation

The resistance and pathogenesis of bacteria could be related to their ability to sense and respond to population density, termed quorum sensing (QS). Inhibition of the QS system is considered as a novel strategy for the development of antipathogenic agents, especially for combating drug-resistant bacterial infections. In the present study, the anti-QS activity of Onion peel ethylacetate fraction (ONE) was tested against Chromobacterium violaceum CV12472 and Pseudomonas aeruginosa PAO1. ONE inhibit the QS-mediated virulence factors production such as violacein in C. violaceum and elastase, pyocyanin in P. aeruginosa. Further, the treatment with sub-MICs of ONE significantly inhibited the QS-mediated biofilm formation, EPS (Extracellular polymeric substances) production and swarming motility. Further, quercetin 4′-O-β-D glucopyranoside (QGP) was isolated from ONE and its anti-QS potential was confirmed after observing significant inhibition of QS-controlled virulence factors such as violacein, elastase, pyocyanin and biofilm formation in test pathogens. Molecular docking analysis predicted that QGP should be able to bind at the active sites of Vfr and LasR, and if so blocks the entry of active sites in Vfr and LasR.

Anticancer activity and concurrent analysis of ursolic acid, β-sitosterol and lupeol in three different Hibiscus species (aerial parts) by validated HPTLC method

The genus Hibiscus contains about 275 species of flowering plants widely grown in the tropics and sub-tropics. The available literature revealed that several Hibiscus species exhibited excellent anticancer activity against several cancer cells like lung, breast, and liver. This motivated the authors to explore the anticancer property of other Hibiscus species (Hibiscus calyphyllus, H. deflersii and H. micranthus) along with development of a validated HPTLC method for the concurrent analysis of three anticancer biomarkers (ursolic acid, β-sitosterol and lupeol) in different Hibiscus species. The anticancer activity of various fractions (petroleum ether, toluene, dichloromethane, ethyl acetate and n-butanol) of all the Hibiscus species (aerial parts) were evaluated in vitro against HepG2 and MCF-7 cell lines using MTT assay. The HPTLC analysis was carried out using chloroform and methanol as mobile phase (97:3; v/v) on 20 × 10 cm glass-backed silica gel 60F254 plates and analyzed different phytoconstituents present in all fractions at λ = 575 nm wavelength. Of the tested fractions of H. calyphyllus, H. deflersii and H. micranthus, HdP (H. deflersii petroleum ether fraction) exhibited the most potent cytotoxic effect on HepG2 and MCF-7 (IC50: 14.4 and 11.1 μg/mL, respectively) cell lines. Using the developed HPTLC method a compact and intense peak of ursolic acid, β-sitosterol and lupeol were obtained at Rf = 0.22, 0.39 and 0.51, respectively. The LOD/LOQ (ng) for ursolic acid, β-sitosterol and lupeol were found as 42.30/128.20, 13.20/40.01 and 31.57/95.68, respectively in the linearity range 100–1200 ng/spot. The obtained result showed maximum presence of ursolic acid, β-sitosterol and lupeol (5.50, 11.85 and 7.47 μg/mg, respectively) in HdP which also supported its strong anticancer effect. Our data suggest that H. deflersii petroleum ether fraction (HdP) can be further subjected to the isolation of active cytotoxic phytoconstituents and establishment of their mechanism of action. The maiden developed HPTLC method for concurrent analysis of anticancer biomarkers may be further employed in the in process quality control of herbal formulation containing the said biomarkers.

Anti-quorum and biofilm formation inhibition by coffee husk oil (Coffee arabica L.)

The volatile oil of the coffee husk of Coffee arabica (Rubiaceae) was obtained by GCMS. This oil showed quorum sensing inhibition activity which were investigated for antipathogenic potential against P. aeruginosa (PAO1). The results showed that significant inhibition on the production of virulence P. aeruginosa and Biofilm Formation (BF). Moreover, the treatment with sub-MICs of coffee husk oil significantly inhibited the quorum sensing-mediated BF, extracellular polymeric substances production and swarming motility in these pathogens. Wide-spectrum in vitro inhibition of QS controlled virulence factors such as violacein, elastase, pyocyanin, EPS and biofilm in test pathogens was determined.

Simultaneous quantification of two phenolic biomarkers by a validated high-performance thin-layer chromatographic method in antimicrobial and antioxidant active ethyl acetate fraction of Allium cepa L. (peel)

In this study, we have developed a validated high-performance thin-layer chromatographic (HPTLC) method for the simultaneous quantification of two phenolic biomarkers, protocatechuic acid (compound 1) and quercetin 4′-O-β-D-glucopyranoside (compound 2) in antimicrobial and antioxidant active A. cepa ethyl acetate extract (ACEAE). The quantitative analysis was carried out on normal-phase HPTLC (glass-backed silica gel 60 F254) plates with solvents toluene, ethyl acetate, and formic acid in the ratio of 3:6:1, v/v (as the mobile phase). Well-resolved, compact, and intense peaks of compound 1 (RF = 0.56 ± 0.001) and compound 2 (RF = 0.05 ± 0.001) were found at λmax = 275 nm. The linear regression equation / r2 for compound 1 (Y = 8.89X + 250.71 / 0.994) and compound 2 (Y = 6.64 X + 209.34 / 0.998) in the concentration range of 100–700 ng spot-1 indicated good linear relationship. The low values of percent relative standard deviation (%RSD) for intra-day / inter-day precision of compound 1 (1.14–1.26 / 1.08–1.23) and compound 2 (0.97–1.18 / 0.93–1.16) suggested that the method is precise. The (%) recoveries for compound 1 / compound 2 were found as 98.07–99.55 / 98.20– 99.89 which confrms the good accuracy of the proposed method. The quantities (%w/w) of compound 1 / compound 2 in ACEAE were found as 18.84% / 13.64% of the dried weight of the extract. In vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay showed the promising free radical scavenging activity of ACEAE (69.00 ± 2.99%) and compound 2 (63.86 ± 2.02%) which were comparable to ascorbic acid tested at 400 µg mL-1. ACEAE was found to be highly active against all tested bacterial strains, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa; however, Candida albicans was found to be susceptible to both compound 2 and ACEAE. The presence of compound 2 in high quantity in the ethyl acetate fractions of A. cepa peel (ACEAE) validated its antimicrobial and antioxidant property. The above developed HPTLC method can be further employed in the analysis of these markers in marketed formulations and in the quality control of herbal drugs.