Farkaad A. Kadir

Understanding the chemistry behind the antioxidant activities of butylated hydroxytoluene (BHT): a review.

Hindered phenols find a wide variety of applications across many different industry sectors. Butylated hydroxytoluene (BHT) is a most commonly used antioxidant recognized as safe for use in foods containing fats, pharmaceuticals, petroleum products, rubber and oil industries. In the past two decades, there has been growing interest in finding novel antioxidants to meet the requirements of these industries. To accelerate the antioxidant discovery process, researchers have designed and synthesized a series of BHT derivatives targeting to improve its antioxidant properties to be having a wide range of antioxidant activities markedly enhanced radical scavenging ability and other physical properties. Accordingly, some structure-activity relationships and rational design strategies for antioxidants based on BHT structure have been suggested and applied in practice. We have identified 14 very sensitive parameters, which may play a major role on the antioxidant performance of BHT. In this review, we attempt to summarize the current knowledge on this topic, which is of significance in selecting and designing novel antioxidants using a well-known antioxidant BHT as a building-block molecule. Our strategy involved investigation on understanding the chemistry behind the antioxidant activities of BHT, whether through hydrogen or electron transfer mechanism to enable promising anti-oxidant candidates to be synthesized.

Gastroprotective Activity of Polygonum chinense Aqueous Leaf Extract on Ethanol-Induced Hemorrhagic Mucosal Lesions in Rats

Polygonum chinense is a Malaysian ethnic plant with various healing effects. This study was to determine preventive effect of aqueous leaf extract of P. chinense against ethanol-induced gastric mucosal injury in rats. Sprague Dawley rats were divided into seven groups. The normal and ulcer control groups were orally administered with distilled water. The reference group was orally administered with 20 mg/kg omeprazole. The experimental groups received the extracts 62.5, 125, 250, and 500 mg/kg, accordingly. After sixty minutes, distilled water and absolute ethanol were given (5 mL/kg) to the normal control and the others, respectively. In addition to histology, immunohistochemical and periodic acid schiff (PAS) stains, levels of lipid peroxidation, malondialdehyde (MDA), antioxidant enzymes, and superoxide dismutase (SOD) were measured. The ulcer group exhibited severe mucosal damages. The experimental groups significantly reduced gastric lesions and MDA levels and increased SOD level. Immunohistochemistry of the experimental groups showed upregulation and downregulation of Hsp70 and Bax proteins, respectively. PAS staining in these groups exhibited intense staining as compared to the ulcer group. Acute toxicity study revealed the nontoxic nature of the extract. Our data provide first evidence that P. chinense extract could significantly prevent gastric ulcer.

Effect of Tinospora crispa on thioacetamide-induced liver cirrhosis in rats

Objectives: This study was conducted to determine the effect of ethanolic extract of the dried stems of Tinospora crispa in a male rat model of hepatic fibrosis caused by the hepatotoxin, thioacetamide. Materials and Methods: The extract was gavaged daily to the rats, at doses of 100 and 200 mg/kg along with thioacetamide at a dose of 200 mg/kg twice weekly. To assess the effectivity of extract, against thioacetamide, the activity of aminotransferases (alanine aminotransferase, aspartate aminotransferase), alkaline phosphatase (AP); and bilirubin were measured, together with morphological and histopathological indices in the liver of healthy and thioacetamide-treated rats. Results: A significant increase in the activity of liver enzymes, bilirubin and G-glutamyl transferase and gross and histopathological changes were determined. Although previous in vitro study established that this extract had strong antioxidant activity, this in vivo study establishes that this extract contains hepatotoxins whose identity may be quite different from those compounds with antioxidant properties. Conclusion: The study confirms that complete reliance on data obtained using in vitro methodologies may lead to erroneous conclusions pertaining to the safety of phytopharmaceuticals.

Hepatoprotective Role of Ethanolic Extract of Vitex negundo in Thioacetamide-Induced Liver Fibrosis in Male Rats

The hepatoprotective activity of ethanolic extract from the leaves of Vitex negundo (VN) was conducted against thioacetamide- (TAA-) induced hepatic injury in Sprague Dawley rats. The therapeutic effect of the extract was investigated on adult male rats. Rats were divided into seven groups: control, TAA, Silymarin (SY), and VN high dose and low dose groups. Rats were administered with VN extract at two different doses, 100 mg/kg and 300 mg/kg body weight. After 12 weeks, the rats administered with VN showed a significantly lower liver to body weight ratio. Their abnormal levels of biochemical parameters and liver malondialdehyde were restored closer to the normal levels and were comparable to the levels in animals treated with the standard drug, SY. Gross necropsy and histopathological examination further confirmed the results. Progression of liver fibrosis induced by TAA in rats was intervened by VN extract administration, and these effects were similar to those administered with SY. This is the first report on hepatoprotective effect of VN against TAA-induced liver fibrosis.

PASS-Predicted Hepatoprotective Activity of Caesalpinia sappan in Thioacetamide-Induced Liver Fibrosis in Rats

The antifibrotic effects of traditional medicinal herb Caesalpinia sappan (CS) extract on liver fibrosis induced by thioacetamide (TAA) and the expression of transforming growth factor β1 (TGF-β1), α-smooth muscle actin (αSMA), and proliferating cell nuclear antigen (PCNA) in rats were studied. A computer-aided prediction of antioxidant and hepatoprotective activities was primarily performed with the Prediction Activity Spectra of the Substance (PASS) Program. Liver fibrosis was induced in male Sprague Dawley rats by TAA administration (0.03% w/v) in drinking water for a period of 12 weeks. Rats were divided into seven groups: control, TAA, Silymarin (SY), and CS 300 mg/kg body weight and 100 mg/kg groups. The effect of CS on liver fibrogenesis was determined by Massons trichrome staining, immunohistochemical analysis, and western blotting. In vivo determination of hepatic antioxidant activities, cytochrome P450 2E1 (CYP2E1), and matrix metalloproteinases (MPPS) was employed. CS treatment had significantly increased hepatic antioxidant enzymes activity in the TAA-treated rats. Liver fibrosis was greatly alleviated in rats when treated with CS extract. CS treatment was noted to normalize the expression of TGF-β1, αSMA, PCNA, MMPs, and TIMP1 proteins. PASS-predicted plant activity could efficiently guide in selecting a promising pharmaceutical lead with high accuracy and required antioxidant and hepatoprotective properties.

Rational Design and Synthesis of New, High Efficiency, Multipotent Schiff Base-1,2,4-triazole Antioxidants Bearing Butylated Hydroxytoluene Moieties

A new series of multipotent antioxidants (MPAOs), namely Schiff base-1,2,4-triazoles attached to the oxygen-derived free radical scavenging moiety butylated hydroxytoluene (BHT) were designed and subsequently synthesized. The structure-activity relationship (SAR) of the designed antioxidants was established alongside the prediction of activity spectra for substances (PASS). The antioxidant activities of the synthesized compounds 4–10 were tested by the DPPH bioassay. The synthesized compounds 4–10 inhibited stable DPPH free radicals at a level that is 10−4 M more than the well-known standard antioxidant BHT. Compounds 8–10 with para-substituents were less active than compounds 4 and 5 with trimethoxy substituents compared to those with a second BHT moiety (compounds 6 and 7). With an IC50 of 46.13 ± 0.31 µM, compound 6 exhibited the most promising in vitro inhibition at 89%. Therefore, novel MPAOs containing active triazole rings, thioethers, Schiff bases, and BHT moieties are suggested as potential antioxidants for inhibiting oxidative stress processes and scavenging free radicals, hence, this combination of functions is anticipated to play a vital role in repairing cellular damage, preventing various human diseases and in medical therapeutic applications.

Graphene– gold based nanocomposites applications in cancer diseases; Efficient detection and therapeutic tools

Early detection and efficient treatment of cancer disease remains a drastic challenge in 21st century. Throughout the bulk of funds, studies, and current therapeutics, cancer seems to aggressively advance with drug resistance strains and recurrence rates. Nevertheless, nanotechnologies have indeed given hope to be the next generation for oncology applications. According to US National cancer institute, it is anticipated to revolutionize the perspectives of cancer diagnosis and therapy. With such success, nano-hybrid strategy creates a marvelous preference. Herein, graphene-gold based composites are being increasingly studied in the field of oncology, for their outstanding performance as robust vehicle of therapeutic agents, built-in optical diagnostic features, and functionality as theranostic system. Additional modes of treatments are also applicable including photothermal, photodynamic, as well as combined therapy. This review aims to demonstrate the various cancer-related applications of graphene-gold based hybrids in terms of detection and therapy, highlighting the major attributes that led to designate such system as a promising ally in the war against cancer.

Antioxidant Properties and Gastroprotective Effects of 2-(Ethylthio)Benzohydrazones on Ethanol-Induced Acute Gastric Mucosal Lesions in Rats.

A series of new 2-(ethylthio)benzohydrazone derivatives (1–6) were prepared and characterised by IR, 1H NMR, and 13C NMR spectroscopy and mass spectrometry. The newly prepared compounds were screened for their in vitro antioxidant activities using free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Among them, most powerful antioxidant, compound 1 has been selected in order to illustrate anti-ulcer effect on ethanol-induced gastric mucosal lesions in rats. Four groups of Sprague Dawley rats were respectively treated with 10% Tween 20 as ulcer control group, 20 mg/kg omeprazole as reference group, 50 mg/kg and 100 mg/kg compound 1 as experimental animals. Macroscopically, ulcer control group showed extensive hemorrhagic lesions of gastric mucosa compared with omeprazole or compound 1. Rats pre-treated with compound 1 showed increased in gastric pH and gastric mucus. Histologically, ulcer control group showed severe damage to gastric mucosa with edema and leucocytes infiltration of submucosal layer. In immunohistochemical analysis, rats which were pre-treated with compound 1 showed up-regulation of HSP70 and down-regulation of Bax proteins. In conclusion, the gastroprotective effect of compound 1 may be due to its antioxidant activity, and/or due to up-regulation of HSP70 and down-regulation of Bax protein in stained tissue section.

Synthesis, PASS-Predication and in Vitro Antimicrobial Activity of Benzyl 4-O-benzoyl-α-l-rhamnopyranoside Derivatives

Benzyl α-l-rhamnopyranoside 4, obtained by both conventional and microwave assisted glycosidation techniques, was subjected to 2,3-O-isopropylidene protection to yield compound 5 which on benzoylation and subsequent deprotection of isopropylidene group gave the desired 4-O-benzoylrhamnopyranoside 7 in reasonable yield. Di-O-acetyl derivative of benzoate 7 was prepared to get newer rhamnopyranoside. The structure activity relationship (SAR) of the designed compounds was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antimicrobial activities verified the predictions obtained by the PASS software. Protected rhamnopyranosides 5 and 6 exhibited slight distortion from regular 1C4 conformation, probably due to the fusion of pyranose and isopropylidene ring. Synthesized rhamnopyranosides 4–8 were employed as test chemicals for in vitro antimicrobial evaluation against eight human pathogenic bacteria and two fungi. Antimicrobial and SAR study showed that the rhamnopyranosides were prone against fungal organisms as compared to that of the bacterial pathogens. Interestingly, PASS prediction of the rhamnopyranoside derivatives 4–8 were 0.49 < Pa < 0.60 (where Pa is probability ‘to be active’) as antibacterial and 0.65 < Pa < 0.73 as antifungal activities, which showed significant agreement with experimental data, suggesting rhamnopyranoside derivatives 4–8 were more active against pathogenic fungi as compared to human pathogenic bacteria thus, there is a more than 50% chance that the rhamnopyranoside derivative structures 4–8 have not been reported with antimicrobial activity, making it a possible valuable lead compound.

The Effects of Combined Adiponectin-Metformin on Glucose and Lipids Levels in Mice and Acute Toxicity and Anti-Ulcerogenic Activity of Adiponectin Against Ethanol-Induced Gastric Mucosal Injuries in Rat

Adiponectin is a protein hormone secreted entirely by abdominal fat tissue. It exhibits various biological activities. The present study was performed to evaluate the effects of metformin alone or in combination with adiponectin on blood glucose, TG (triglyceride), CHOL (Total cholesterol), LDL (Low density lipoprotein) and HDL (High density lipoprotein) levels in mice and also to evaluate the anti-ulcerogenic activity of adiponectin against ethanol induced gastric mucosal injury in rats. Three groups of mice were gavaged with 1% volume/body weight high fat-sucrose. Metformin at a dosage of 250 mg/kg was added to the feed and a dosage of 2.5 mg/kg adiponectin was injected intraperitoneally (i.p). Blood glucose was measured at one hour intervals for five hours. Blood concentrations of TG, CHOL, LDL and HDL were also measured at the end of the fifth hour of the experiment. On the other hand, four groups of adult healthy rats were i.p. injected with distilled water, omeprazole 20 mg/kg, 2.5 mg/kg and 5 mg/kg adiponectin one hour before oral administration of absolute ethanol to generate gastric mucosal injury. After an additional hour the rats were sacrificed and the ulcer areas of the gastric walls were determined. Furthermore, an acute toxicity study has indicated no mortality with 5 mg/kg dose of adiponectin injected i.p in rats and no major clinical signs of toxicity were observed. The results indicate that the effect of a combination of metformin and adiponectin on blood glucose and HDL is quite effective. Histology of the gastric wall of negative control rats revealed severe damage of gastric mucosa, along with edema and leucocyte infiltration of the submucosal layer compared to rats pre-treated with either omeprazole or adiponectin extract where there was marked gastric protection along with reduction or inhibition of edema and leucocytes infiltration. The results suggest that combination of metfomin and adiponectin give a promising antidiabetic effect and also, adiponectin promotes ulcer protection as ascertained by the comparative decrease of ulcer areas, reduction of edema and leucocytes infiltration of the submucosal layer.