Shean Yeaw Ng

Dr. Shean Yeaw Ng

Institute for Tropical Biology and Conservation
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 September 2022 in Molecules
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Journal Article
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MBMohammad Amil Zulhilmi Benjamin
Mohammad Amil Zulhilmi Benjamin
SNShean Yeaw Ng
Shean Yeaw Ng
FSFiffy Hanisdah Saikim
Fiffy Hanisdah Saikim
NRNOR AZIZUN RUSDI
NOR AZIZUN RUSDI
The therapeutic potential of bamboos has acquired global attention. Nonetheless, the biological activities of the plants are rarely considered due to limited available references in Sabah, Malaysia. Furthermore, the drying technique could significantly affect the retention and degradation of nutrients in bamboos. Consequently, the current study investigated five drying methods, namely, sun, shade, microwave, oven, and freeze-drying, of the leaves of six bamboo species, Bambusa multiplex, Bambusa tuldoides, Bambusa vulgaris, Dinochloa sublaevigata, Gigantochloa levis, and Schizostachyum brachycladum. The infused bamboo leaves extracts were analysed for their total phenolic content (TPC) and total flavonoid content (TFC). The antioxidant activities of the samples were determined via the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays, whereas their toxicities were evaluated through the brine shrimp lethality assay (BSLA). The chemical constituents of the samples were determined using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The freeze-drying method exhibited the highest phytochemical contents and antioxidant activity yield, excluding the B. vulgaris sample, in which the microwave-dried sample recorded the most antioxidant and phytochemical levels. The TPC and TFC results were within the 2.69 ± 0.01–12.59 ± 0.09 mg gallic acid equivalent (GAE)/g and 0.77 ± 0.01–2.12 ± 0.01 mg quercetin equivalent (QE)/g ranges, respectively. The DPPH and ABTS IC50 (half-maximal inhibitory concentration) were 2.92 ± 0.01–4.73 ± 0.02 and 1.89–0.01 to 3.47 ± 0.00 µg/mL, respectively, indicating high radical scavenging activities. The FRAP values differed significantly between the drying methods, within the 6.40 ± 0.12–36.65 ± 0.09 mg Trolox equivalent (TE)/g range. The phytochemical contents and antioxidant capacities exhibited a moderate correlation, revealing that the TPC and TFC were slightly responsible for the antioxidant activities. The toxicity assessment of the bamboo extracts in the current study demonstrated no toxicity against the BSLA based on the LC50 (lethal concentration 50) analysis at >1000 µg/mL. LC-MS analysis showed that alkaloid and pharmaceutical compounds influence antioxidant activities, as found in previous studies. The acquired information might aid in the development of bamboo leaves as functional food items, such as bamboo tea. They could also be investigated for their medicinal ingredients that can be used in the discovery of potential drugs.

18 November 2020 in Molecules
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Journal Article
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SNShean Yeaw Ng
Shean Yeaw Ng
CPChin-Soon Phan
Chin-Soon Phan
TITakahiro Ishii
Takahiro Ishii
TKTakashi Kamada
Takashi Kamada
THToshiyuki Hamada
Toshiyuki Hamada
CVCharles S. Vairappan
Charles S. Vairappan
Members of the marine soft coral genus Xenia are rich in a diversity of diterpenes. A total of 199 terpenes consisting of 14 sesquiterpenes, 180 diterpenes, and 5 steroids have been reported to date. Xenicane diterpenes were reported to be the most common chemical skeleton biosynthesized by members of this genus. Most of the literature reported the chemical diversity of Xenia collected from the coral reefs in the South China Sea and the coastal waters of Taiwan. Although there was a brief review on the terpenoids of Xenia in 2015, the present review is a comprehensive overview of the structural diversity of secondary metabolites isolated from soft coral genus Xenia and their potent biological activity as reported between 1977 to 2019.

19 May 2015 in Marine Drugs
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CPChin-Soon Phan
Chin-Soon Phan
SNShean Yeaw Ng
Shean Yeaw Ng
EKEun-A Kim
Eun-A Kim
You-Jin JeonYou-Jin Jeon
You-Jin Jeon
KPKishneth Palaniveloo
Kishneth Palaniveloo
CVCharles S. Vairappan
Charles S. Vairappan
Two new bicyclogermacrenes, capgermacrenes A (1) and B (2), were isolated with two known compounds, palustrol (3) and litseagermacrane (4), from a population of Bornean soft coral Capnella sp. The structures of these metabolites were elucidated based on spectroscopic data. Compound 1 was found to inhibit the accumulation of the LPS-induced pro-inflammatory IL-1b and NO production by down-regulating the expression of iNOS protein in RAW 264.7 macrophages.

1 February 2016 in Journal of Asian Natural Products Research
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Journal Article
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SNShean Yeaw Ng
Shean Yeaw Ng
TKTakashi Kamada
Takashi Kamada
MSMonica Suleiman
Monica Suleiman
CVCharles S. Vairappan
Charles S. Vairappan
A new compound, chandonanol (1), along with four known compounds, chandonanthone (2), iso-chandonanthone (3), anastreptene (4), and (6R,7S)-sesquiphellandrene (5), was isolated from the MeOH extract of Bornean liverwort Chandonanthus hirtellus. The structure of the new metabolite was established by analyses of the spectroscopic data (1D NMR, 2D NMR, HRESIMS, and IR). These compounds were tested for their activity against antibiotic-resistant clinical strains. Chandonanol (1) exhibited potent bactericidal activity against Staphylococcus aureus and Escherichia coli.

29 October 2021 in International Journal of Analytical Chemistry
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ASAzrul Hisyam Samsuri
Azrul Hisyam Samsuri
MAMay Yen Ang
May Yen Ang
SNShean Yeaw Ng
Shean Yeaw Ng
This study aims to determine the residual hexane in four edible oils in Malaysia using a simple, rapid, and automated method in order to improve the efficiency and productivity of the analysis. Gas chromatography (GC/FID) equipped with a headspace autosampler (HS-20) was used to perform the analysis. Incubation time for each injection was successfully optimized from one hour to 30 minutes (50 reduction) compared to the official AOCS method Ca 3b-87. Out of the four tested edible oils, only the hexane residues detected in sunflower oil exceeded the maximum residue limit (MRL) set by the European Union regulation. Significant difference of the results obtained between large calibration range (0938mg kg−1) and small calibration range (068mg kg−1) suggests that there is a need to use a lower standard calibration concentration to avoid misinterpretation of analysis results. Method validation applies to the technical hexane; 2-methylpentane, 3-methylpentane, cyclohexane, and methylcyclopentane, the signal-to-noise (S/N), as well as the limit of quantification (LoQ) values was found to be 218.20, 221.45, 746.37, 97.37 and 0.85, 0.84, 0.25, 1.93mg kg−1, respectively. Good linearity, repeatability, and low carryover of this method have provided an alternative way to analyze the content of the residual hexane in edible oils in a more efficient manner. Current study might provide a fundamental reference for the improvement of the AOCS official Ca 3b-87 method for determination of hexane residues in fats and oils analysis in the future.

1 July 2016 in Natural Product Communications
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CPChin-Soon Phan
Chin-Soon Phan
SNShean Yeaw Ng
Shean Yeaw Ng
TKTakashi Kamada
Takashi Kamada
CVCharles S. Vairappan
Charles S. Vairappan
Two new lobane diterpenoids, prenyl-α-elemenone (1) and ent-prenyl-β-elemene (2), along with a known compound, α-murrolene (3) were isolated from a population of Bornean soft coral Sinularia sp. The structures of these compounds were elucidated on the basis of spectroscopic, including 2D NMR, and HR-MS data. These compounds were tested for their cytotoxicity and antibacterial activities against antibiotic resistant clinical strains.