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Fulltext Chemical Composition, Antioxidant and Cytoprotective Potentials of Carica papaya Leaf Extracts: A Comparison of Supercritical Fluid and Conventional Extraction Methods

Khor BK, Chear NJ, Azizi J, Khaw KY

Molecules, 2021 Mar 09;26(5).
PMID: 33803330 DOI: 10.3390/molecules26051489

The leaves of Carica papaya (CP) are rich in natural antioxidants. Carica papaya has traditionally been used to treat various ailments, including skin diseases. This study aims to decipher the antioxidant effects and phytochemical content of different CP leaf extracts (CPEs) obtained using supercritical carbon dioxide (scCO2) and conventional extraction methods. The antioxidant activities of CPEs were evaluated by cell-free (1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ferric-reduced antioxidative power (FRAP)) and cell-based (H2O2) assay. Both C. papaya leaf scCO2 extract with 5% ethanol (CPSCE) and C. papaya leaf scCO2 extract (CPSC) exhibited stronger DPPH radical scavenging activity than conventional extracts. In the FRAP assay, two hydrophilic extracts (C. papaya leaf ethanol extract (CPEE) and C. papaya freeze-dried leaf juice (CPFD)) showed relatively stronger reducing power compared to lipophilic extracts. Cell-based assays showed that CPFD significantly protected skin fibroblasts from H2O2-induced oxidative stress in both pre-and post-treatment. CPEE protected skin fibroblasts from oxidative stress in a dose-dependent manner while CPSCE significantly triggered the fibroblast recovery after treatment with H2O2. GC-MS analysis indicated that CPSCE had the highest α-tocopherol and squalene contents. By contrast, both CP hydrophilic extracts (CPEE and CPFD) had a higher total phenolic content (TPC) and rutin content than the lipophilic extracts. Overall, CPEs extracted using green and conventional extraction methods showed antioxidative potential in both cell-based and cell-free assays due to their lipophilic and hydrophilic antioxidants, respectively.
Fulltext Kratom Alkaloids: Interactions With Enzymes, Receptors, and Cellular Barriers

Hanapi NA, Chear NJ, Azizi J, Yusof SR

Front Pharmacol, 2021;12:751656.
PMID: 34867362 DOI: 10.3389/fphar.2021.751656

Parallel to the growing use of kratom, there is a wealth of evidence from self-report, preclinical, and early clinical studies on therapeutic benefits of its alkaloids in particular for treating pain, managing substance use disorder, and coping with emotional or mental health conditions. On the other hand, there are also reports on potential health risks concerning kratom use. These two aspects are often discussed in reviews on kratom. Here, we aim to highlight specific areas that are of importance to give insights into the mechanistic of kratom alkaloids pharmacological actions. This includes their interactions with drug-metabolizing enzymes and predictions of clinical drug-drug interactions, receptor-binding properties, interactions with cellular barriers in regards to barrier permeability, involvement of membrane transporters, and alteration of barrier function when exposed to the alkaloids.
Development and validation of a gradient HPLC-UV method for mitragynine following in vitro skin permeation studies

Sim YS, Chong ZY, Azizi J, Goh CF

J Chromatogr B Analyt Technol Biomed Life Sci, 2022 Jul 15;1204:123316.
PMID: 35700649 DOI: 10.1016/j.jchromb.2022.123316

Mitragynine is a promising candidate for pain relief and opiate replacement but the investigations for drug delivery are lacking. This study aims to investigate the potential of mitragynine to be delivered through the skin with an emphasis on developing and validating a gradient HPLC-UV analytical method to determine mitragynine in the samples collected during in vitro skin permeation studies. The optimised method involves a gradient elution using a C18 column with a mobile phase comprising acetonitrile and 0.1 %v/v of formic acid (0-1 min: 30:70 to 70:30 (v/v) and hold up to 4 min; 4-6 min: return to 30:70 (v/v) and hold up to 10 min) at a flow rate of 1.2 mL/min. This method was validated based on the standards set by the International Council on Harmonisation guidelines. The method showed mitragynine elution at ∼ 4 min with adequate linearity (R2 ≥ 0.999 for concentration ranges of 0.5-10 and 10-175 μg/mL) and acceptable limits of detection and quantification at 0.47 and 1.43 μg/mL, respectively. The analytical performance is robust with excellent precision and accuracy. This method was used to evaluate the in vitro skin permeation of mitragynine (5 %w/v) from simple solvent systems over 48 hr. The results showed a cumulative amount of mitragynine permeated at ∼ 11 μg/cm2 for dimethyl sulfoxide and ∼ 4 μg/cm2 for propylene glycol. The study not only addressed the issues of the currently available HPLC-UV methods that limit the direct application but also affirmed the potential of mitragynine to be delivered through the skin.
Corrigendum to "Development and validation of a gradient HPLC-UV method for mitragynine following in vitro skin permeation studies" [J. Chromatogr. B 1204 (2022) 123316]

Sim YS, Chong ZY, Azizi J, Goh CF

J Chromatogr B Analyt Technol Biomed Life Sci, 2024 Feb 21;1235:124066.
PMID: 38417273 DOI: 10.1016/j.jchromb.2024.124066
Fulltext Potential Applications of Conducting Polymers to Reduce Secondary Bacterial Infections among COVID-19 Patients: a Review

Mahat MM, Sabere ASM, Azizi J, Amdan NAN

Emergent Mater, 2021;4(1):279-292.
PMID: 33649739 DOI: 10.1007/s42247-021-00188-4

The COVID-19 pandemic is a motivation for material scientists to search for functional materials with valuable properties to alleviate the risks associated with the coronavirus. The formulation of functional materials requires synergistic understanding on the properties of materials and mechanisms of virus transmission and disease progression, including secondary bacterial infections that are prevalent in COVID-19 patients. A viable candidate in the struggle against the pandemic is antimicrobial polymer, due to their favorable properties of flexibility, lightweight, and ease of synthesis. Polymers are the base material for personal protective equipment (PPE), such as gloves, face mask, face shield, and coverall suit for frontliners. Conducting polymers (CPs) are polymers with electrical properties due to the addition of dopant in the polymer structure. The conductivity of polymers augments their antiviral and antibacterial properties. This review discusses the types of CPs and how their properties could be exploited to ward off bacterial infections in hospital settings, specifically in cases involving COVID-19 patients. This review also covers common CPs fabrication techniques. The key components to produce CPs at several possibilities to fit the current needs in fighting secondary bacterial infections are also discussed.
Fulltext Evaluation of antioxidant and antibacterial activities of aqueous, methanolic and alkaloid extracts from Mitragyna speciosa (Rubiaceae family) leaves

Parthasarathy S, Bin Azizi J, Ramanathan S, Ismail S, Sasidharan S, Said MI, et al.

Molecules, 2009;14(10):3964-74.
PMID: 19924042 DOI: 10.3390/molecules14103964

Studies on the antioxidant and antimicrobial activities of Mitragyna speciosa leaf extracts are lacking. In this study the antioxidant properties of water, methanolic and alkaloid M. speciosa leaf extracts were evaluated using the DPPH (2,2-diphenyl-1- picrylhydrazyl) radical scavenging method. The amount of total phenolics and flavanoid contents were also estimated. The DPPH IC(50) values of the aqueous, alkaloid and methanolic extracts were 213.4, 104.81 and 37.08 microg/mL, respectively. The total phenolic content of the aqueous, alkaloid and methanolic extracts were 66.0 mg, 88.4, 105.6 mg GAE/g, respectively, while the total flavanoid were 28.2, 20.0 and 91.1 mg CAE/g respectively. The antioxidant activities were correlated with the total phenolic content. This result suggests that the relatively high antioxidant activity of the methanolic extract compared to aqueous and alkaloid extract could be possibly be due to its high phenolic content. The aqueous, alkaloid and methanolic extracts were screened for antimicrobial activity. The extracts showed antimicrobial activity against Salmonella typhi and Bacillus subtilis. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 3.12 to 6.25 mg/mL. The alkaloid extract was found to be most effective against all of the tested organisms.
Fulltext In vitro and in vivo effects of three different Mitragyna speciosa korth leaf extracts on phase II drug metabolizing enzymes--glutathione transferases (GSTs)

Azizi J, Ismail S, Mordi MN, Ramanathan S, Said MI, Mansor SM

Molecules, 2010 Jan 20;15(1):432-41.
PMID: 20110902 DOI: 10.3390/molecules15010432

In the present study, we investigate the effects of three different Mitragyna speciosa extracts, namely methanolic, aqueous and total alkaloid extracts, on glutathione transferase-specific activity in male Sprague Dawley rat liver cytosol in vitro and in vivo. In the in vitro study, the effect of Mitragyna speciosa extracts (0.01 to 750 microg/mL) against the specific activity of glutathione transferases was examined in rat liver cytosolic fraction from untreated rats. Our data show concentration dependent inhibition of cytosolic GSTs when Mitragyna speciosa extract was added into the reaction mixture. At the highest concentration used, the methanolic extract showed the highest GSTs specific activity inhibition (61%), followed by aqueous (50%) and total alkaloid extract (43%), respectively. In in vivo study, three different dosages; 50, 100 and 200 mg/kg for methanolic and aqueous extracts and 5, 10 and 20 mg/kg for total alkaloid extract were given orally for 14 days. An increase in GST specific activity was generally observed. However, only Mitragyna speciosa aqueous extract with a dosage of 100 mg/kg showed significant results: 129% compared to control.
Fulltext Soft-Chewable Paracetamol Tablets by Melt Granulation Method: Formulation and Characterization

Sabere ASM, Suhaimi NANM, Ahmed QU, Mahat MM, Roslan NC, Azizi J

J Pharm Bioallied Sci, 2021 11 24;13(3):312-316.
PMID: 35017887 DOI: 10.4103/jpbs.JPBS_783_20

Background: Oral drug delivery is the most preferred route for drug administration in the world, with tablets being one of the most common dosage forms. However, some people, particularly children and the elderly, have difficulty swallowing the tablets. Chewable tablets are the dosage form that can address the issue while also providing a valuable masking effect on drug taste, allowing patients to swallow the drugs more easily.
Materials and Methods: In this study, the chewable tablets were manufactured using the melt granulation method, which resulted in tablets with a chewy texture. The tablets contained paracetamol as well as Arabic gum, starch, agar, and mannitol.
Results: The drug release profiles for the fragmented form showed that 50% of the drug was released within 4 min and 100% was released within 30 min of the dissolution process. The intact form released nearly 90% of the drug within 2 h.
Conclusion: Formulation 2 was determined as the best formulation. This tablets' formulation had passed all characterization tests and displayed a moderate hardness and chewy texture.
Changes in blood-brain barrier permeability and ultrastructure, and protein expression in a rat model of cerebral hypoperfusion

Sekaran H, Gan CY, A Latiff A, Harvey TM, Mohd Nazri L, Hanapi NA, et al.

Brain Res Bull, 2019 10;152:63-73.
PMID: 31301381 DOI: 10.1016/j.brainresbull.2019.07.010

Cerebral hypoperfusion involved a reduction in cerebral blood flow, leading to neuronal dysfunction, microglial activation and white matter degeneration. The effects on the blood-brain barrier (BBB) however, have not been well-documented. Here, two-vessel occlusion model was adopted to mimic the condition of cerebral hypoperfusion in Sprague-Dawley rats. The BBB permeability to high and low molecular weight exogenous tracers i.e. Evans blue dye and sodium fluorescein respectively, showed marked extravasation of the Evans blue dye in the frontal cortex, posterior cortex and thalamus-midbrain at day 1 following induction of cerebral hypoperfusion. Transmission electron microscopy revealed brain endothelial cell and astrocyte damages including increased pinocytotic vesicles and formation of membrane invaginations in the endothelial cells, and swelling of the astrocytes' end-feet. Investigation on brain microvessel protein expressions using two-dimensional (2D) gel electrophoresis coupled with LC-MS/MS showed that proteins involved in mitochondrial energy metabolism, transcription regulation, cytoskeleton maintenance and signaling pathways were differently expressed. The expression of aconitate hydratase, heterogeneous nuclear ribonucleoprotein, enoyl Co-A hydratase and beta-synuclein were downregulated, while the opposite observed for calreticulin and enhancer of rudimentary homolog. These findings provide insights into the BBB molecular responses to cerebral hypoperfusion, which may assist development of future therapeutic strategies.
A simple and efficient sequential electrokinetic and hydrodynamic injections in micellar electrokinetic chromatography method for quantification of anticancer drug 5-fluorouracil and its metabolite in human plasma

Semail NF, Noordin SS, Keyon ASA, Waras MN, Saad B, Kamaruzaman S, et al.

Biomed Chromatogr, 2021 May;35(5):e5050.
PMID: 33314228 DOI: 10.1002/bmc.5050

A simple and sensitive preconcentration strategy using sequential electrokinetic and hydrodynamic injection modes in micellar electrokinetic chromatography with diode array detection was developed and applied for the separation and determination of anticancer agent, 5-fluorouracil and its metabolite, 5-fluoro-2'-deoxyuridine, in human plasma. Sequential injection modes with increased analyte loading capacity using the anionic pseudo-stationary phase facilitated collection of the dispersed neutral and charged analytes into narrow zones and improved sensitivity. Several important parameters affecting sample enrichment performance were evaluated and optimized in this study. Under the optimized experimental conditions, 614- and 643-fold and 782- and 803-fold sensitivity improvement were obtained for 5-fluorouracil and its metabolite when compared with normal hydrodynamic and electrokinetic injection, respectively. The method has good linearity (1-1,000 ng/ml) with acceptable coefficient of determination (r2 > 0.993), low limits of detection (0.11-0.14 ng/ml) and satisfactory analyte relative recovery (97.4-99.7%) with relative standard deviations of 4.6-9.3% (n = 6). Validation results as well as the application to analysis of human plasma samples from cancer patients demonstrate the applicability of the proposed method to clinical studies.