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Thyroid function status evaluation in patient post-radiotherapy for nasopharyngeal carcinoma: A retrospective study

Loh ZH, Mohamad S, Gan BC, Zakaria Z, Mohamad I

Med J Malaysia, 2023 Mar;78(2):197-201.
PMID: 36988530

INTRODUCTION: Nasopharyngeal carcinoma (NPC) is among the most common malignancy in Malaysia. Radiationinduced hypothyroidism has been reported in other countries. However, in Malaysia, no studies were ever done to determine the effect of radiation on hypothyroidism. The objective of this study is to evaluate the practice of taking thyroid function test (TFT) and determine hypothyroidism post-radiation in patients with NPC.
MATERIALS AND METHODS: A retrospective study on the symptoms and results of TFT according to the dosage of intensity-modulated radiotherapy (IMRT) given to patients with NPC. Data were traced and analysed.
RESULTS: A total of 78 patients were identified. All patients received IMRT with 33-35 fractions of radiotherapy (RT) with total dosage of 66-70 Gray given. Not all patients had their thyroid function status measured routinely. Twelve patients did have symptoms of hypothyroidism. TFT were obtained in this group but the results were normal. No correlation was found between RT and hypothyroidism.
CONCLUSION: There was no correlation between IMRT and the development of hypothyroidism. A prospective study with better control of inclusion and exclusion criteria, and longer follow-up period with TFT, is needed to demonstrate the consistency of these findings.
Fulltext Novel biphenyl ester derivatives as tyrosinase inhibitors: Synthesis, crystallographic, spectral analysis and molecular docking studies

Kwong HC, Chidan Kumar CS, Mah SH, Chia TS, Quah CK, Loh ZH, et al.

PLoS One, 2017;12(2):e0170117.
PMID: 28241010 DOI: 10.1371/journal.pone.0170117

Biphenyl-based compounds are clinically important for the treatments of hypertension and inflammatory, while many more are under development for pharmaceutical uses. In the present study, a series of 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl benzoates, 2(a-q), and 2-([1,1'-biphenyl]-4-yl)-2-oxoethyl pyridinecarboxylate, 2(r-s) were synthesized by reacting 1-([1,1'-biphenyl]-4-yl)-2-bromoethan-1-one with various carboxylic acids using potassium carbonate in dimethylformamide at ambient temperature. Single-crystal X-ray diffraction studies revealed a more closely packed crystal structure can be produced by introduction of biphenyl moiety. Five of the compounds among the reported series exhibited significant anti-tyrosinase activities, in which 2p, 2r and 2s displayed good inhibitions which are comparable to standard inhibitor kojic acid at concentrations of 100 and 250 μg/mL. The inhibitory effects of these active compounds were further confirmed by computational molecular docking studies and the results revealed the primary binding site is active-site entrance instead of inner copper binding site which acted as the secondary binding site.
Fulltext New 3-O-substituted xanthone derivatives as promising acetylcholinesterase inhibitors

Loh ZH, Kwong HC, Lam KW, Teh SS, Ee GCL, Quah CK, et al.

J Enzyme Inhib Med Chem, 2021 Dec;36(1):627-639.
PMID: 33557647 DOI: 10.1080/14756366.2021.1882452

A new series of 3-O-substituted xanthone derivatives were synthesised and evaluated for their anti-cholinergic activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The results indicated that the xanthone derivatives possessed good AChE inhibitory activity with eleven of them (5, 8, 11, 17, 19, 21-23, 26-28) exhibited significant effects with the IC50 values ranged 0.88 to 1.28 µM. The AChE enzyme kinetic study of 3-(4-phenylbutoxy)-9H-xanthen-9-one (23) and ethyl 2-((9-oxo-9H-xanthen-3-yl)oxy)acetate (28) showed a mixed inhibition mechanism. Molecular docking study showed that 23 binds to the active site of AChE and interacts via extensive π-π stacking with the indole and phenol side chains of Trp86 and Tyr337, besides the hydrogen bonding with the hydration site and π-π interaction with the phenol side chain of Y72. This study revealed that 3-O-alkoxyl substituted xanthone derivatives are potential lead structures, especially 23 and 28 which can be further developed into potent AChE inhibitors.
Alkaloids and Styryl Lactones from Goniothalamus tortilipetalus and Their Biological Activities

Champakam S, Patrick BO, Injan N, Nokbin S, Cheenpracha S, Loh ZH, et al.

J Nat Prod, 2024 Nov 07.
PMID: 39508737 DOI: 10.1021/acs.jnatprod.4c00933

Phytochemical investigations of the twig and leaf extracts of Goniothalamus tortilipetalus resulted in the isolation and identification of two new alkaloids, goniotortiline (1) and goniotortilactam (2), three new styryl lactone derivatives, goniotortilactone (3) and goniotortilols A (4) and B (5), and 25 known compounds. Their structures were elucidated by spectroscopic methods and HRESITOFMS data. Compounds 5, 13, 15, 16, 22, and 30 inhibited nitric oxide (NO) production with IC50 values ranging from 8.7 ± 0.1 to 17 ± 1 μM, revealing stronger effects than the standard drug, dexamethasone (IC50 16.9 ± 2.2 μM), and compound 30 possessed the most potent NO production inhibition. Compounds 12 and 29 demonstrated notable efficacy in enhancing glucose consumption with IC50 values of 77 ± 4 and 66 ± 4 μM, respectively, while their glucose uptakes were 1.7- and 2-fold, respectively.