Arifah Abdul Kadir

Chemical constituents and antihistamine activity of Bixa orellana leaf extract

BackgroundBixa orellana L. has been traditionally used in Central and South America to treat a number of ailments, including internal inflammation, and in other tropical countries like Malaysia as treatment for gastric ulcers and stomach discomfort. The current study aimed to determine the major chemical constituents of the aqueous extract of B. orellana (AEBO) and to evaluate the antihistamine activity of AEBO during acute inflammation induced in rats.MethodsAcute inflammation was produced by subplantar injection of 0.1 mL of 0.1% histamine into the right hind paw of each rat in the control and treatment groups. The degree of edema was measured before injection and at the time points of 30, 60, 120, 180, 240 and 300 min after injection. Changes of peritoneal vascular permeability were studied using Evans blue dye as a detector. Vascular permeability was evaluated by the amount of dye leakage into the peritoneal cavity in rats. To evaluate the inhibitory effect of AEBO on biochemical mediators of vascular permeability, the levels of nitric oxide (NO) and vascular endothelial growth factor (VEGF) were determined in histamine-treated paw tissues. The major constituents of AEBO were determined by gas chromatography–mass spectrometry (GC-MS) analysis.ResultsAEBO produced a significant inhibition of histamine-induced paw edema starting at 60 min time point, with maximal percentage of inhibition (60.25%) achieved with a dose of 150 mg/kg of AEBO at 60 min time point. Up to 99% of increased peritoneal vascular permeability produced by histamine was successfully suppressed by AEBO. The expression of biochemical mediators of vascular permeability, NO and VEGF, was also found to be downregulated in the AEBO treated group. Gas chromatography–mass spectrometry (GC-MS) analysis revealed that the major constituent in AEBO was acetic acid.ConclusionsThe experimental findings demonstrated that the anti-inflammatory activity of AEBO was due to its inhibitory effect on vascular permeability, which was suppressed as a result of the reduced expression of biochemical mediators (NO and VEGF) in tissues. Our results contribute towards the validation of the traditional use of Bixa orellana in the treatment of inflammatory disorders.

Lack of hepato- and nephrotoxicity induced by antifungal drug voriconazole in laboratory rats

Voriconazole is a new, potent broad-spectrum triazole systemic antifungal drug, a second-generation azole antifungal that is increasing in popularity, especially for the treatment of invasive aspergillosis and fluconazole-resistant invasive Candida infections. However, it is also known to induce hepatotoxicity clinically. The aim of this study was to investigate the hepatotoxicity and nephrotoxicity potential of voriconazole in vivo in rats. Forty rats were treated intraperitoneally with voriconazole as single (0, 10, l00, and 200 mg/kg) or repeated (0, 10, 50, and l00 mg/kg per day for 14 days) doses. Venous blood was collected for the repeated-dose group on days 1 and 14. Rats were sacrificed 24 hours after the last dose. Body weight, liver weight, and kidney weight of rats were recorded. Livers and kidneys samples were taken for histological and transmission electron microscopy (TEM) analysis. Results revealed that voriconazole had no effects on serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphotase, gamma glutamyl transpeptidase, blood urea nitrogen, and creatinine for both the single- and repeated-dose groups. However, histologically, in the repeated 50- and 100-mg/kg voriconazole-treated rats, mild focal inflammation was observed. Under TEM, only small changes in the 100 mg/kg/day group were revealed. These results collectively demonstrated that voriconazole did not induce significant hepatotoxicity and nephrotoxicity, even at very high doses.

Methanolic Extract of Clinacanthus nutans Exerts Antinociceptive Activity via the Opioid/Nitric Oxide-Mediated, but cGMP-Independent, Pathways

The objectives of the present study were to determine the mechanisms of antinociceptive effect of methanol extract of Clinacanthus nutans (Acanthaceae) leaves (MECN) using various animal nociceptive models. The antinociceptive activity of orally administered 10% DMSO, 100 mg/kg acetylsalicylic acid (ASA), 5 mg/kg morphine, or MECN (100, 250, and 500 mg/kg) was determined using the acetic acid-induced abdominal constriction (ACT), formalin-induced paw licking (FT), and hot plate tests (HPT). The role of opioid and nitric oxide/cyclic guanosine monophosphate (NO/cGMP) systems was also investigated. The results showed that MECN produced a significant (p < 0.05) antinociceptive response in all nociceptive models with the recorded ED50 value of 279.3 mg/kg for the ACT, while, for the early and late phases of the FT, the value was >500 mg/kg or 227.7 mg/kg, respectively. This antinociceptive activity was fully antagonized by naloxone (a nonselective opioid antagonist) but was partially reversed by l-arginine (l-arg; a nitric oxide [NO] precursor), Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME; an NO synthase inhibitor), or their combinations thereof. In contrast, 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ; a soluble guanylyl cyclase inhibitor) enhanced the extracts antinociception. UHPLC analysis revealed the presence of several flavonoid-based compounds with antinociceptive action. In conclusion, MECN exerted the peripherally and centrally mediated antinociceptive activity via the modulation of the opioid/NO-mediated, but cGMP-independent, systems.

Artonin E induces p53-independent G1 cell cycle arrest and apoptosis through ROS-mediated mitochondrial pathway and livin suppression in MCF-7 cells

Artonin E is a prenylated flavonoid compound isolated from the stem bark of Artocarpus elasticus. This phytochemical has been previously reported to be drug-like with full compliance to Lipinski’s rule of five and good physicochemical properties when compared with 95% of orally available drugs. It has also been shown to possess unique medicinal properties that can be utilized in view of alleviating most human disease conditions. In this study, we investigated the cytotoxic mechanism of Artonin E in MCF-7 breast cancer cells, which has so far not been reported. In this context, Artonin E significantly suppressed the breast cancer cell’s viability while inducing apoptosis in a dose-dependent manner. This apoptosis induction was caspase dependent, and it is mediated mainly through the intrinsic pathway with the elevation of total reactive oxygen species. Gene and protein expression studies revealed significant upregulation of cytochrome c, Bax, caspases 7 and 9, and p21 in Artonin E-treated MCF-7 cells, while MAPK and cyclin D were downregulated. Livin, a member of the inhibitors of apoptosis, whose upregulation has been noted to precede chemotherapeutic resistance and apoptosis evasion was remarkably repressed. In all, Artonin E stood high as a potential agent in the treatment of breast cancer.

Free radical scavenging activity of conjugated linoleic acid as single or mixed isomers.

Context: Conjugated linoleic acids (CLAs) are a mixture of positional and geometric isomers of linoleic acid (LA) and believed to have many positive biological activities. Objective: The present study was undertaken to assess the antioxidant activity of cis-9, trans-11 and trans-10, cis-12 as single or mixed CLA isomers at two ratios, 1:6 and 1:13 (trans-10, cis-12/cis-9, trans-11). Materials and methods: A microplate reader was used to determine the free radical scavenging properties of CLAs against DPPH radical in ethanol. Results: The kinetic reactions of CLA-DPPH• showed that all tested CLAs have exerted radical scavenging activities in a dose-dependent manner and observed to immediately react and quench DPPH radicals at all tested levels and no lag phase was noticed in CLA-DPPH• reactions. The median inhibitory concentration (IC50) value for cis-9, trans-11 CLA was observed to be more effective than other tested CLA. Total antioxidant capacity (TAC) of all tested CLAs were less effective radical scavengers as compared to vitamin E and butylated hydroxytoluene, although all tested CLAs were quenched a high amount (P < 0.05) of DPPH free radicals. Discussion and conclusion: All tested CLAs have the ability to directly react and quench DPPH free radicals in ethanol. Furthermore, trans-10, cis-12 CLA has greater maximal efficacy than other tested CLAs as free radical scavenger, while cis-9, trans-11 CLA is the most potent isomer to directly react and quench free radicals at low concentrations in the system, suggesting that the free radical scavenging activity of CLA isomers may contribute to their diverse biological activities.

The molecular mechanism of the anticancer effect of Artonin E in MDA-MB 231 triple negative breast cancer cells

Nature has provided us with a wide spectrum of disease healing phytochemicals like Artonin E, obtained from the root bark of Artocarpus elasticus. This molecule had been predicted to be drug-like, possessing unique medicinal properties. Despite strides made in chemotherapy, prognosis of the heterogenous aggressive triple negative breast cancer is still poor. This study was conducted to investigate the mechanism of inhibition of Artonin E, a prenylated flavonoid on MDA-MB 231 triple negative breast cancer cell, with a view of mitigating the hallmarks displayed by these tumors. The anti-proliferative effect, mode of cell death and the mechanism of apoptosis induction were investigated. Artonin E, was seen to effectively relinquish MDA-MB 231 breast cancer cells of their apoptosis evading capacity, causing a half-maximal growth inhibition at low concentrations (14.3, 13.9 and 9.8 μM) after the tested time points (24, 48 and 72 hours), respectively. The mode of cell death was observed to be apoptosis with defined characteristics. Artonin E was seen to induce the activation of both extrinsic and intrinsic caspases initiators of apoptosis. It also enhanced the release of total reactive oxygen species which polarized the mitochondrial membrane, compounding the release of cytochrome c. Gene expression studies revealed the upregulation of TNF-related apoptosis inducing ligand and proapoptotic genes with down regulation of anti-apoptotic genes and proteins. A G2/M cell cycle arrest was also observed and was attributed to the observed upregulation of p21 independent of the p53 status. Interestingly, livin, a new member of the inhibitors of apoptosis was confirmed to be significantly repressed. In all, Artonin E showed the potential as a promising candidate to combat the aggressive triple negative breast cancer.

Artonin E and Structural Analogs from Artocarpus Species Abrogates Estrogen Receptor Signaling in Breast Cancer.

The increasing rate of mortality ensued from breast cancer has encouraged research into safer and efficient therapy. The human Estrogen receptor α has been implicated in the majority of reported breast cancer cases. Molecular docking employing Glide, Schrodinger suite 2015, was used to study the binding affinities of small molecules from the Artocarpus species after their drug-like properties were ascertained. The structure of the ligand-binding domain of human Estrogen receptor α was retrieved from Protein Data Bank while the structures of compounds were collected from PubChem database. The binding interactions of the studied compounds were reported as well as their glide scores. The best glide scored ligand, was Artonin E with a score of −12.72 Kcal when compared to other studied phytomolecules and it evoked growth inhibition of an estrogen receptor positive breast cancer cells in submicromolar concentration (3.8–6.9 µM) in comparison to a reference standard Tamoxifen (18.9–24.1 µM) within the tested time point (24–72 h). The studied ligands, which had good interactions with the target receptor, were also drug-like when compared with 95% of orally available drugs with the exception of Artoelastin, whose predicted physicochemical properties rendered it less drug-like. The in silico physicochemical properties, docking interactions and growth inhibition of the best glide scorer are indications of the anti-breast cancer relevance of the studied molecules.

Antinociceptive Activity of Methanolic Extract of Clinacanthus nutans Leaves: Possible Mechanisms of Action Involved

Methanolic extract of Clinacanthus nutans Lindau leaves (MECN) has been proven to possess antinociceptive activity that works via the opioid and NO-dependent/cGMP-independent pathways. In the present study, we aimed to further determine the possible mechanisms of antinociception of MECN using various nociceptive assays. The antinociceptive activity of MECN was (i) tested against capsaicin-, glutamate-, phorbol 12-myristate 13-acetate-, bradykinin-induced nociception model; (ii) prechallenged against selective antagonist of opioid receptor subtypes (β-funaltrexamine, naltrindole, and nor-binaltorphimine); (iii) prechallenged against antagonist of nonopioid systems, namely, α2-noradrenergic (yohimbine), β-adrenergic (pindolol), adenosinergic (caffeine), dopaminergic (haloperidol), and cholinergic (atropine) receptors; (iv) prechallenged with inhibitors of various potassium channels (glibenclamide, apamin, charybdotoxin, and tetraethylammonium chloride). The results demonstrated that the orally administered MECN (100, 250, and 500 mg/kg) significantly (p < 0.05) reversed the nociceptive effect of all models in a dose-dependent manner. Moreover, the antinociceptive activity of 500 mg/kg MECN was significantly (p < 0.05) inhibited by (i) antagonists of μ-, δ-, and κ-opioid receptors; (ii) antagonists of α2-noradrenergic, β-adrenergic, adenosinergic, dopaminergic, and cholinergic receptors; and (iii) blockers of different K+ channels (voltage-activated-, Ca2+-activated, and ATP-sensitive-K+ channels, resp.). In conclusion, MECN-induced antinociception involves modulation of protein kinase C-, bradykinin-, TRVP1 receptors-, and glutamatergic-signaling pathways; opioidergic, α2-noradrenergic, β-adrenergic, adenosinergic, dopaminergic, and cholinergic receptors; and nonopioidergic receptors as well as the opening of various K+ channels. The antinociceptive activity could be associated with the presence of several flavonoid-based bioactive compounds and their synergistic action with nonvolatile bioactive compounds.

Two new chemical constituents from the stem bark of Garcinia mangostana.

A detailed chemical study on the ethyl acetate and methanol extracts of the stem bark of Garcinia mangostana resulted in the successful isolation of one new prenylated xanthone, mangaxanthone B (1), one new benzophenone, mangaphenone (2), and two known xanthones, mangostanin (3) and mangostenol (4). The structures of these compounds were elucidated through analysis of their spectroscopic data obtained using 1D and 2D NMR and MS techniques.

Comparative experimental study of Brucella melitensis and its lipopolysaccharide in mouse model infected via subcutaneous route of exposure

Brucella melitensis is a major zoonotic pathogen in which lipopolysaccharide (LPS) is believed to play a major role in the diseases pathogenesis. To study the immunopathophysiological aspects, we established a mouse model experimentally infected with whole cell of B. melitensis and its lipopolysaccharide via subcutaneous route of exposure. Eighty four mice, BALB/c, both sexes with equal gender distribution and 6-8 weeks-old were randomly assigned into 3 groups. Group 1 (n = 36) were subcutaneoulsy inoculated with 0.4 mL 109 of B. melitensis while group 2 (n = 36) were subcutaneously challenged with 0.4 mL 109 of LPS. Group 3 (n = 12) was challenged subcuatneously with phosphate buffered saline and served as a control group. Animals were observed for clinical signs, haematological and histopathological analysis for a period of 24 days post-inoculation. Our results revealed that B. melitensis infected group demonstrated significant clinical signs and histopathological evidence than LPS infected group. However, both infected groups showed elevated levels of interleukins (IL-1β & IL6), antibody levels (IgM & IgG) as early as 3 days post-infection with predominance in LPS infected group. For hormone analysis, low levels of progesterone, estradiol and testosterone were observed in both B. melitensis and LPS challenged groups throughout the study period. Moreover, in B. melitensis infected groups, the organism was re-isolated from the organs and tissues of gastrointestinal, respiratory and reproductive systems; thereby confirming the possible transmission of the disease dynamics. Moreover, LPS stimulated significantly the innate and acquired immune system without significant systemic dysfunction suggesting the potentiality of the protective properties of this component as an alternative vaccine for brucellosis infection. This report is the first detailed investigation comparing the infection progression and host responses in relation to the immunopathophysiological aspects in mouse model after subcutaneous inoculation with B. melitensis and its lipopolysaccharide.