Displaying publications 1 - 20 of 30 in total

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  1. Tan SC, Rajendran R, Bhattamisra SK, Krishnappa P, Davamani F, Chitra E, et al.
    J Pharm Pharmacol, 2023 Aug 01;75(8):1034-1045.
    PMID: 37402616 DOI: 10.1093/jpp/rgad063
    OBJECTIVES: Madecassoside (MAD) is a triterpenoid constituent of Centella asiatica (L.) Urb., an ethnomedical tropical plant, extracts of which were shown to reduce blood glucose in experimental diabetes. This study examines MAD for its anti-hyperglycaemic effects and tests the hypothesis that it reduces the blood glucose in experimentally induced diabetic rats by protecting the β-cells.

    METHODS: Diabetes was induced using streptozotocin (60 mg/kg, i.v.) followed by nicotinamide (210 mg/kg, intraperitoneal (i.p.)). MAD (50 mg/kg) was administered orally for 4 weeks, commencing 15 days after induction of diabetes; resveratrol (10 mg/kg) was used as a positive control. Fasting blood glucose, plasma insulin, HbA1c, liver and lipid parameters were measured, along with antioxidant enzymes and malondialdehyde as an index of lipid peroxidation; histological and immunohistochemical studies were also undertaken.

    KEY FINDINGS: MAD normalized the elevated fasting blood glucose levels. This was associated with increased plasma insulin concentrations. MAD alleviated oxidative stress by improving enzymatic antioxidants and reducing lipid peroxidation. Histopathological examination showed significant recovery of islet structural degeneration and an increased area of islets. Immunohistochemical staining showed increased insulin content in islets of MAD-treated rats.

    CONCLUSIONS: The results demonstrate an antidiabetic effect of MAD associated with preservation of β-cell structure and function.

  2. Cherian S, Hacisayidli KM, Kurian R, Mathews A
    J Pharm Pharmacol, 2023 Mar 12;75(3):301-327.
    PMID: 36757388 DOI: 10.1093/jpp/rgac105
    OBJECTIVES: Increasing literature data have suggested that the genus Polygonum L. possesses pharmacologically important plant secondary metabolites. These bioactive compounds are implicated as effective agents in preclinical and clinical practice due to their pharmacological effects such as anti-inflammatory, anticancer, antidiabetic, antiaging, neuroprotective or immunomodulatory properties among many others. However, elaborate pharmacological and clinical data concerning the bioavailability, tissue distribution pattern, dosage and pharmacokinetic profiles of these compounds are still scanty.

    KEY FINDINGS: The major bioactive compounds implicated in the therapeutic effects of Polygonum genus include phenolic and flavonoid compounds, anthraquinones and stilbenes, such as quercetin, resveratrol, polydatin and others, and could serve as potential drug leads or as adjuvant agents. Data from in-silico network pharmacology and computational molecular docking studies are also highly helpful in identifying the possible drug target of pathogens or host cell machinery.

    SUMMARY: We provide an up-to-date overview of the data from pharmacodynamic, pharmacokinetic profiles and preclinical (in-vitro and in-vivo) investigations and the available clinical data on some of the therapeutically important compounds of genus Polygonum L. and their medical interventions, including combating the outbreak of the COVID-19 pandemic.

  3. Chung WJ, Chan KL, Lee CY
    J Pharm Pharmacol, 2021 Mar 04;73(2):161-168.
    PMID: 33793798 DOI: 10.1093/jpp/rgaa026
    OBJECTIVES: The quassinoids eurycomanone (EN) and 13α,21-dihydroeurycomanone (DHY) of Eurycoma longifolia Jack are reported to enhance spermatogenesis. This study aims to profile the pharmacokinetics of DHY, a minor and hitherto unstudied constituent, evaluate its spermatogenesis enhancement property and compare these attributes with that of the predominant EN.

    METHODS: Crude Eurycoma longifolia extract was chromatographed into a DHY-enriched extract (DHY-F) and an EN-enriched extract (EN-F). Male Sprague-Dawley rats were administered intravenously and orally with both extracts and their plasma levels of both quassinoids were determined. The extracts were then tested for their spermatogenesis augmentation ability in normal rats and an andrographolide-induced oligospermia model.

    KEY FINDINGS: Chromatographic enrichment resulted in a 28-fold increase of DHY in DHY-F and a 5-fold increase of EN in EN-F compared with non-chromatographed crude extracts. DHY showed better oral bioavailability (1.04 ± 0.58%) than EN (0.31 ± 0.19%). At 5 mg/kg, EN exhibited higher efficacy in spermatogenesis enhancement in normal rats and restoration of oligospermia to normal sperm profile versus DHY.

    CONCLUSIONS: Despite the better pharmacokinetic profile of DHY, EN remains the main chemical contributor to plant bioactivity. DHY-F and EN-F represent improvements in developing Eurycoma longifolia as a potential phytomedicine for male infertility particularly oligospermia.

  4. Salleh WMNHW, Abed SA, Taher M, Kassim H, Tawang A
    J Pharm Pharmacol, 2021 Mar 01;73(1):1-21.
    PMID: 33791809 DOI: 10.1093/jpp/rgaa034
    OBJECTIVES: The genus Ferulago belonging to the family Apiaceae is a flora widely distributed in Central Asia and the Mediterranean and used in folk medicine. It is administered as a sedative, tonic, digestive, aphrodisiac, also as a treatment for intestinal worms and haemorrhoids. Herein, we reported a review on phytochemistry and its biological activities reported from 1990 up to early 2020. All the information and reported studies concerning Ferulago plants were summarized from the library and digital databases (e.g. Scopus, Medline, Scielo, ScienceDirect, SciFinder and Google Scholar).

    KEY FINDINGS: The phytochemical investigations of Ferulago species revealed the presence of coumarins as the main bioactive compounds, including daucane derivatives, sesquiterpenes aryl esters, phenol derivatives, flavonoids and essential oils. Moreover, the therapeutic potentials of the pure compounds isolated from the genus Ferulago possess promising properties namely anticholinesterase, antimicrobial, anticoagulant, antileishmanial, antioxidant, antibacterial and antiproliferative.

    SUMMARY: Today, significant advances in phytochemical and biological activity studies of different Ferulago species have been revealed. The traditional uses and reported biological results could be correlated via the chemical characterization of these plants. All these data will support the biologists in the elucidation of the biological mechanisms of these plants.

  5. Tiang N, Ahad MA, Murugaiyah V, Hassan Z
    J Pharm Pharmacol, 2020 Nov;72(11):1629-1644.
    PMID: 32743849 DOI: 10.1111/jphp.13345
    OBJECTIVES: Xanthones isolated from the pericarp of Garcinia mangostana has been reported to exhibit neuroprotective effect.

    METHODS: In this study, the effect of xanthone-enriched fraction of Garcinia mangostana (XEFGM) and α-mangostin (α-MG) were investigated on cognitive functions of the chronic cerebral hypoperfusion (CCH) rats.

    KEY FINDINGS: HPLC analysis revealed that XEFGM contained 55.84% of α-MG. Acute oral administration of XEFGM (25, 50 and 100 mg/kg) and α-MG (25 and 50 mg/kg) before locomotor activity and Morris water maze (MWM) tests showed no significant difference between the groups for locomotor activity.

    CONCLUSIONS: However, α-MG (50 mg/kg) and XEFGM (100 mg/kg) reversed the cognitive impairment induced by CCH in MWM test. α-MG (50 mg/kg) was further tested upon sub-acute 14-day treatment in CCH rats. Cognitive improvement was shown in MWM test but not in long-term potentiation (LTP). BDNF but not CaMKII was found to be down-regulated in CCH rats; however, both parameters were not affected by α-MG. In conclusion, α-MG ameliorated learning and memory deficits in both acute and sub-acute treatments in CCH rats by improving the spatial learning but not hippocampal LTP. Hence, α-MG may be a promising lead compound for CCH-associated neurodegenerative diseases, including vascular dementia and Alzheimer's disease.

  6. Yap PK, Loo Xin GL, Tan YY, Chellian J, Gupta G, Liew YK, et al.
    J Pharm Pharmacol, 2019 Sep;71(9):1339-1352.
    PMID: 31144296 DOI: 10.1111/jphp.13107
    OBJECTIVES: Antiretroviral agents (ARVs) have been the most promising line of therapy in the management of human immunodeficiency virus (HIV) infections. Some of these ARVs are used in the pre-exposure prophylaxis (PrEP) to suppress the transmission of HIV. Prophylaxis is primarily used in uninfected people, before exposure, to effectively prevent HIV infection. Several studies have shown that ART PrEP prevents HIV acquisition from sexual, blood and mother-to-child transmissions. However, there are also several challenges and limitations to PrEP. This review focuses on the current antiretroviral therapies used in PrEP.

    KEY FINDINGS: Among ARVs, the most common drugs employed from the class of entry inhibitors are maraviroc (MVC), which is a CCR5 receptor antagonist. Other entry inhibitors like emtricitabine (FTC) and tenofovir (TFV) are also used. Rilpivirine (RPV) and dapivirine (DPV) are the most common drugs employed from the Non-nucleoside reverse transcriptase inhibitor (NNRTIs) class, whereas, tenofovir disoproxil fumarate (TDF) is primarily used in the Nucleoside Reverse Transcriptase Inhibitor (NRTIs) class. Cabotegravir (CAB) is an analog of dolutegravir, and it is an integrase inhibitor. Some of these drugs are also used in combination with other drugs from the same class.

    SUMMARY: Some of the most common pre-exposure prophylactic strategies employed currently are the use of inhibitors, namely entry inhibitors, non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, integrase and protease inhibitors. In addition, we have also discussed on the adverse effects caused by ART in PrEP, pharmacoeconomics factors and the use of antiretroviral prophylaxis in serodiscordant couples.

  7. Lee EH, Lim SS, Yuen KH, Lee CY
    J Pharm Pharmacol, 2019 May;71(5):860-868.
    PMID: 30515807 DOI: 10.1111/jphp.13052
    OBJECTIVES: This study aims to investigate the blood-brain barrier (BBB) permeability of curcumin analogues with shortened linkers and their ability to protect against amyloid-beta toxicity in a whole organism model.

    METHOD: Four curcumin analogues were synthesized. These analogues and curcumin were evaluated for their BBB permeability in the parallel artificial membrane permeability assay. The transgenic Caenorhabditis elegansGMC101 that expresses human Aβ1-42 was treated with the compounds to evaluate their ability to delay Aβ-induced paralysis. Expression of skn-1mRNA was examined on nematodes treated with selected efficacious compounds. In vitro Aβ aggregation in the presence of the compounds was performed.

    KEY FINDINGS: The four analogues showed improved BBB permeability vs curcumin in the PAMPA with the hemi-analogue C4 having the highest permeability coefficient. At 100 μm, analogues C1 and C4 as well as curcumin significantly prolonged the survival of the nematodes protecting against Aβ toxicity. However, only curcumin and C4 showed protection at lower concentrations. skn-1mRNA was significantly elevated in nematodes treated with curcumin and C4 indicating SKN-1/Nrf activation as a possible mode of action.

    CONCLUSIONS: Analogue C4 provides a new lead for the development of a curcumin-based compound for protection against Aβ toxicity with an improved BBB permeability.

  8. Ali SM, Siddiqui R, Khan NA
    J Pharm Pharmacol, 2018 Oct;70(10):1287-1300.
    PMID: 30003546 DOI: 10.1111/jphp.12976
    OBJECTIVES: Whether vertebrates/invertebrates living in polluted environments are an additional source of antimicrobials.

    KEY FINDINGS: Majority of antimicrobials have been discovered from prokaryotes and those which are of eukaryotic origin are derived mainly from fungal and plant sources. With this in mind, it is important to note that pests, such as cockroaches come across pathogenic bacteria routinely, yet thrive in polluted environments. Other animals, such as snakes thrive from feeding on germ-infested rodents. Logically, such species must have developed an approach to protect themselves from these pathogens, yet they have largely been ignored as a potential source of antimicrobials despite their remarkable capability to fight disease-causing organisms.

    SUMMARY: Animals living in polluted environments are an underutilized source for potential antimicrobials, hence it is believed that several novel bioactive molecule(s) will be identified from these sources to counter increasingly resistant bacterial infections. Further research will be necessary in the development of novel antimicrobial(s) from these unusual sources which will have huge clinical impact worldwide.

  9. Septama AW, Jantan I, Panichayupakaranant P
    J Pharm Pharmacol, 2018 Sep;70(9):1242-1252.
    PMID: 29943393 DOI: 10.1111/jphp.12952
    OBJECTIVES: To investigate the effects of flavonoids isolated from Artocarpus heterophyllus. heartwood on chemotaxis, phagocytosis, reactive oxygen species (ROS) production and myeloperoxidase (MPO) activity of human phagocytes.

    METHODS: Chemotaxis was evaluated using a modified Boyden chamber and phagocytosis was determined by flowcytometer. Respiratory burst was investigated by luminol-based chemiluminescence assay while MPO activity was determined by colorimetric assay.

    KEY FINDINGS: Artocarpanone and artocarpin strongly inhibited all steps of phagocytosis. Artocarpanone and artocarpin showed strong chemotactic activity with IC50 values of 6.96 and 6.10 μm, respectively, which were lower than that of ibuprofen (7.37 μm). Artocarpanone was the most potent compound in inhibiting ROS production of polymorphonuclear leucocytes and monocytes with IC50 values comparable to those of aspirin. Artocarpin at 100 μg/ml inhibited phagocytosis of opsonized bacteria (28.3%). It also strongly inhibited MPO release with an IC50 value (23.3 μm) lower than that of indomethacin (69 μm). Structure-activity analysis indicated that the number of hydroxyl group, the presence of prenyl group and variation of C-2 and C-3 bonds might contribute towards their phagocytosis.

    CONCLUSIONS: Artocarpanone and artocarpin were able to suppress strongly the phagocytosis of human phagocytes at different steps and have potential to be developed into potent anti-inflammatory agents.

  10. Tan SF, Kirby BP, Stanslas J, Basri HB
    J Pharm Pharmacol, 2017 Nov;69(11):1447-1457.
    PMID: 28809443 DOI: 10.1111/jphp.12800
    OBJECTIVE: This study was aimed to investigate the potential of formulated valproic acid-encapsulated nanoemulsion (VANE) to improve the brain bioavailability of valproic acid (VPA).

    METHODS: Valproic acid-encapsulated nanoemulsions were formulated and physically characterised (osmolarity, viscosity, drug content, drug encapsulation efficiency). Further investigations were also conducted to estimate the drug release, cytotoxic profile, in-vitro blood-brain barrier (BBB) permeability, pharmacokinetic parameter and the concentration of VPA and VANE in blood and brain.

    KEY FINDINGS: Physical characterisation confirmed that VANE was suitable for parenteral administration. Formulating VPA into nanoemulsion significantly reduced the cytotoxicity of VPA. In-vitro drug permeation suggested that VANEs crossed the BBB as freely as VPA. Pharmacokinetic parameters of VANE-treated rats in plasma and brain showed F3 VANE had a remarkable improvement in AUC, prolongation of half-life and reduction in clearance compared to VPA. Given the same extent of in-vitro BBB permeation of VPA and VANE, the higher bioavailability of VANE in brain was believed to have due to higher concentration of VANE in blood. The brain bioavailability of VPA was improved by prolonging the half-life of VPA by encapsulating it within the nanoemulsion-T80.

    CONCLUSIONS: Nanoemulsion containing VPA has alleviated the cytotoxic effect of VPA and improved the plasma and brain bioavailability for parenteral delivery of VPA.

  11. Lee NY, Khoo WK, Adnan MA, Mahalingam TP, Fernandez AR, Jeevaratnam K
    J Pharm Pharmacol, 2016 Jun 10.
    PMID: 27283048 DOI: 10.1111/jphp.12565
    Phyllanthus niruri is a traditional shrub of the genus Phyllanthaceae with long-standing Ayurvedic, Chinese and Malay ethnomedical records. Preliminary studies from cell and animal model have provided valuable scientific evidence for its use.
  12. Abubakar IB, Loh HS
    J Pharm Pharmacol, 2016 Apr;68(4):423-32.
    PMID: 26887962 DOI: 10.1111/jphp.12523
    OBJECTIVES: Tabernaemontana is a genus from the plant family, Apocynaceae with vast medicinal application and widespread distribution in the tropics and subtropics of Africa, Americas and Asia. The objective of this study is to critically evaluate the ethnobotany, medicinal uses, pharmacology and phytochemistry of the species, Tabernaemontana corymbosa (Roxb. ex Wall.) and provide information on the potential future application of alkaloids isolated from different parts of the plant.

    KEY FINDINGS: T. corymbosa (Roxb. ex Wall.) parts are used as poultice, boiled juice, decoctions and infusions for treatment against ulceration, fracture, post-natal recovery, syphilis, fever, tumours and orchitis in Malaysia, China, Thailand and Bangladesh. Studies recorded alkaloids as the predominant phytochemicals in addition to phenols, saponins and sterols with vast bioactivities such as antimicrobial, analgesic, anthelmintic, vasorelaxation, antiviral and cytotoxicity.

    SUMMARY: An evaluation of scientific data and traditional medicine revealed the medicinal uses of different parts of T. corymbosa (Roxb. ex Wall.) across Asia. Future studies exploring the structure-bioactivity relationship of alkaloids such as jerantinine and vincamajicine among others could potentially improve the future application towards reversing anticancer drug resistance.

  13. Fung WY, Liong MT, Yuen KH
    J Pharm Pharmacol, 2016 Feb;68(2):159-69.
    PMID: 26730452 DOI: 10.1111/jphp.12502
    OBJECTIVES: This study aimed to prepare Coenzyme Q10 (CoQ10) microparticles using electrospraying technology, and evaluate the in-vitro properties and in-vivo oral bioavailability.
    KEY FINDINGS: Electrospraying was successfully used to prepare CoQ10 to enhance its solubility and dissolution properties. In-vitro evaluation of the electrosprayed microparticles showed bioavailability-enhancing properties such as reduced crystallinity and particle size. The formulation was evaluated using dissolution study and in-vivo oral bioavailability using rat model. The dissolution study revealed enhanced dissolution properties of electrosprayed microparticles compared with physical mixture and raw material. The absorption profiles showed increasing mean plasma levels CoQ10 in the following order: raw material < physical mixture < electrosprayed microparticles.
    CONCLUSION: Based on the findings in this study, electrospraying is a highly prospective technology to produce functional nano- and micro-structures as delivery vehicles for drugs with poor oral bioavailability due to rate-limiting solubility.
  14. Lim AW, Löbmann K, Grohganz H, Rades T, Chieng N
    J Pharm Pharmacol, 2016 Jan;68(1):36-45.
    PMID: 26663364 DOI: 10.1111/jphp.12494
    The objective was to characterize the structural behaviour of indomethacin-cimetidine and naproxen-cimetidine co-amorphous systems (1 : 1 molar ratio) prepared by quench cooling, co-evaporation and ball milling.
  15. Jafari SF, Khadeer Ahamed MB, Iqbal MA, Al Suede FS, Khalid SH, Haque RA, et al.
    J Pharm Pharmacol, 2014 Oct;66(10):1394-409.
    PMID: 25039905 DOI: 10.1111/jphp.12272
    Recently, we have isolated koetjapic acid (KA) from Sandoricum koetjape and identified its selective anticancer potentiality against colorectal carcinoma. KA is quite likely to be useful as a systemic anticancer agent against colorectal malignancy. However, with extremely low solubility, KA has to be converted into a biocompatible solubilized form without compromising the bioefficacy. Objective of this study is to enhance solubility of KA and to evaluate anticancer efficacy of potassium koetjapate in human colorectal cancer cells.
  16. Abeer MM, Mohd Amin MC, Martin C
    J Pharm Pharmacol, 2014 Aug;66(8):1047-61.
    PMID: 24628270 DOI: 10.1111/jphp.12234
    The field of pharmaceutical technology is expanding rapidly because of the increasing number of drug delivery options. Successful drug delivery is influenced by multiple factors, one of which is the appropriate identification of materials for research and engineering of new drug delivery systems. Bacterial cellulose (BC) is one such biopolymer that fulfils the criteria for consideration as a drug delivery material.
  17. Wong TW, Sumiran N
    J Pharm Pharmacol, 2014 May;66(5):646-57.
    PMID: 24329400 DOI: 10.1111/jphp.12192
    Objective: Examine the formation of pectin-insulin nanoparticles and their blood glucose lowering properties.

    Methods: The calcium pectinate nanoparticles were prepared by ionotropic gelation method, with alginate, sodium chloride or Tween 80 as additive. Their in vitro physicochemical, drug release and in vivo blood glucose lowering characteristics were evaluated.

    Key findings: Spherical calcium pectinate-insulin nanoparticles were characterized by size, zeta potential, insulin content and insulin association efficiency of 348.4 ± 12.9 nm, -17.9 ± 0.8 mV, 8.4 ± 1.0% and 63.8 ± 7.4%, respectively. They released less than 25% insulin following 24 h in simulated intestinal medium and exhibited delayed blood glucose lowering effect in rats. Incorporation of solubilizer sodium chloride or Tween 80 into nanoparticles did not enhance blood glucose lowering capacity owing to sodium chloride reduced matrix insulin content and Tween 80 interacted with water and had its blood glucose dilution effect negated. Combination of nanoparticles with alginate gel to allow prolonged intestinal residence and more insulin release did not enhance their blood glucose lowering capacity because of calcium alginate-cross-linked gel formation that could retard insulin release and migration into systemic circulation.

    Conclusion: Physicochemical responses of additives in vivo affected blood glucose regulation property of pectin-insulin nanoparticles.

    Keywords: Tween 80; alginate; insulin; nanoparticle; pectin.
  18. Kirby BP, Pabari R, Chen CN, Al Baharna M, Walsh J, Ramtoola Z
    J Pharm Pharmacol, 2013 Oct;65(10):1473-81.
    PMID: 24028614 DOI: 10.1111/jphp.12125
    In this study, we examined the relative cellular uptake of nanoparticles (NPs) formulated using poly(lactic-co-glycolic acid) (PLGA) polymers with increasing degree of pegylation (PLGA-PEG) and their potential to deliver loperamide to the brain of a mouse.
  19. Muthiah YD, Ong CE, Sulaiman SA, Tan SC, Ismail R
    J Pharm Pharmacol, 2012 Dec;64(12):1761-9.
    PMID: 23146039 DOI: 10.1111/j.2042-7158.2012.01551.x
    To investigate the effect of Tualang honey on cytochrome P450 2C8 (CYP2C8) activity in vitro using an amodiaquine N-desethylase assay.
  20. Jantan I, Bukhari SN, Lajis NH, Abas F, Wai LK, Jasamai M
    J Pharm Pharmacol, 2012 Mar;64(3):404-12.
    PMID: 22309272 DOI: 10.1111/j.2042-7158.2011.01423.x
    A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.
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