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  1. An overview of antimicrobial properties of kombucha
    Nyiew KY, Kwong PJ, Yow YY
    Compr Rev Food Sci Food Saf, 2022 Jan 24.
    PMID: 35075759 DOI: 10.1111/1541-4337.12892
    Kombucha is a traditional beverage of Manchurian origin, typically made by fermenting sugared black or green tea with the symbiotic consortium of bacteria and yeast (SCOBY). The beverage has gained increasing popularity in recent years, mainly due to its heralded health benefits. The fermentation process of kombucha also results in the production of various bioactive compounds with antimicrobial potential, making it a promising candidate in the exploration of alternative sources of antimicrobial agents, and may be helpful in combating the rising threat of antibiotic resistance. Literature survey performed on Web of Science, Scopus, and PubMed revealed the extensive research that has firmly established the antimicrobial activity of kombucha against a broad spectrum of bacteria and fungi. This activity could be attributed to the synergistic activities of the microbial species in the kombucha microbiota that led to the synthesis of compounds with antimicrobial properties such as acetic acid and various polyphenols. However, research thus far only involved screening for the antimicrobial activity of kombucha. Therefore, there is still a research gap about the molecular mechanism of the kombucha reaction against specific pathogens and its influence on human health upon consumption. Future research may focus on investigating this aspect. Further characterization of the biological activity of the microbial community in kombucha may also facilitate the discovery of novel antimicrobial compounds, such as bacteriocins produced by the microorganisms.
  2. LC-MS profiling-based non-targeted secondary metabolite screening for deciphering cosmeceutical potential of Malaysian algae
    Lim MW, Yow YY, Gew LT
    J Cosmet Dermatol, 2023 Oct;22(10):2810-2815.
    PMID: 37313630 DOI: 10.1111/jocd.15794
    BACKGROUND: Application of natural resources from the marine environment in the cosmeceutical industry is gaining great attention.

    AIM: This study pursues to discover the cosmeceutical potential of two Malaysian algae, Sargassum sp. and Kappaphycus sp. by determining their antioxidant capacity and assessing the presence of their secondary metabolites with cosmeceutical potential using non-targeted metabolite profiling.

    METHODS: Metabolite profiling using Quadrupole Time-of-Flight (Q-TOF) liquid chromatography-mass spectrometry (LC-MS) in the Electrospray Ionization (ESI) mode resulted in 110 putative metabolites in Sargassum sp. and 47 putative metabolites in Kappaphycus sp. and were grouped according to their functions. To the best of our knowledge, the bioactive compounds of both algae have not been studied in any great detail. This is the first report to explore their cosmeceutical potential.

    RESULTS: Six antioxidants were detected in Sargassum sp., including fucoxanthin, (3S, 4R, 3'R)-4-Hydroxyalloxanthin, enzacamene N-stearoyl valine, 2-hydroxy-hexadecanoic acid, and metalloporphyrins. Meanwhile, three antioxidants detected in Kappahycus sp., namely Tanacetol A, 2-fluoro palmitic acid and idebenone metabolites. Three antioxidants are found in both algae species, namely, 3-tert-Butyl-5-methylcatechol, (-)-isoamijiol, and (6S)-dehydrovomifoliol. Anti-inflammatory metabolites such as 5(R)-HETE, protoverine, phytosphingosine, 4,5-Leukotriene-A4, and 5Z-octadecenoic acid were also found in both species. Sargassum sp. possesses higher antioxidant capacity as compared to Kappahycus sp. which may be linked to its number of antioxidant compounds found through LC-MS.

    CONCLUSIONS: Hence, our results conclude that Malaysian Sargassum sp. and Kappaphycus sp. are potential natural cosmeceutical ingredients as we aim to produce algae cosmeceutical products using native algae.

  3. Fulltext Metabolite Profiling of Malaysian Gracilaria edulis Reveals Eplerenone as Novel Antibacterial Compound for Drug Repurposing Against MDR Bacteria
    Asghar A, Tan YC, Shahid M, Yow YY, Lahiri C
    Front Microbiol, 2021;12:653562.
    PMID: 34276590 DOI: 10.3389/fmicb.2021.653562
    With a continuous threat of antimicrobial resistance on human health worldwide, efforts for new alternatives are ongoing for the management of bacterial infectious diseases. Natural products of land and sea, being conceived to be having fewer side effects, pose themselves as a welcome relief. In this respect, we have taken a scaffolded approach to unearthing the almost unexplored chemical constituents of Malaysian red seaweed, Gracilaria edulis. Essentially, a preliminary evaluation of the ethyl acetate and acetone solvent extracts, among a series of six such, revealed potential antibacterial activity against six MDR species namely, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, and Bacillus subtilis. Detailed analyses of the inlying chemical constituents, through LC-MS and GC-MS chromatographic separation, revealed a library of metabolic compounds. These were led for further virtual screening against selected key role playing proteins in the virulence of the aforesaid bacteria. To this end, detailed predictive pharmacological analyses added up to reinforce Eplerenone as a natural alternative from the plethora of plausible bioactives. Our work adds the ongoing effort to re-discover and repurpose biochemical compounds to combat the antimicrobial resistance offered by the Gram-positive and the -negative bacterial species.
  4. Fulltext Cryptic diversity: Two morphologically similar species of invasive apple snail in Peninsular Malaysia
    Rama Rao S, Liew TS, Yow YY, Ratnayeke S
    PLoS One, 2018;13(5):e0196582.
    PMID: 29734361 DOI: 10.1371/journal.pone.0196582
    Invasive snails in the genus Pomacea have spread across Southeast Asia including Peninsular Malaysia. Their effects on natural and agricultural wetlands are appreciable, but species-specific effects are less clear because of morphological similarity among the species. Our objective was to establish diagnostic characteristics of Pomacea species in Malaysia using genetic and morphological criteria. The mitochondrial COI gene of 52 adult snails from eight localities in Peninsular Malaysia was amplified, sequenced, and analysed to verify species and phylogenetic relationships. Shells were compared using geometric morphometric and covariance analyses. Two monophyletic taxa, P. canaliculata and P. maculata, occurred in our samples. The mean ratio of shell height: aperture height (P = 0.042) and shell height: shell width (P = 0.007) was smaller in P. maculata. P. maculata co-occurred with P. canaliculata in five localities, but samples from three localities contained only P. canaliculata. This study is the first to confirm the presence of two of the most invasive species of Pomacea in Peninsular Malaysia using a molecular technique. P. canaliculata appears to be the more widespread species. Despite statistical differences, both quantitative and qualitative morphological characteristics demonstrated much interspecific overlap and intraspecific variability; thus, shell morphology alone cannot reliably verify species identity. Molecular techniques for distinguishing between these two highly invasive Pomacea species are needed to understand their specific ecological niches and to develop effective protocols for their management.
  5. Fulltext The efficiency of universal mitochondrial DNA barcodes for species discrimination of Pomacea canaliculata and Pomacea maculata
    Kannan A, Rama Rao S, Ratnayeke S, Yow YY
    PeerJ, 2020;8:e8755.
    PMID: 32274263 DOI: 10.7717/peerj.8755
    Invasive apple snails, Pomacea canaliculata and P. maculata, have a widespread distribution globally and are regarded as devastating pests of agricultural wetlands. The two species are morphologically similar, which hinders species identification via morphological approaches and species-specific management efforts. Advances in molecular genetics may contribute effective diagnostic tools to potentially resolve morphological ambiguity. DNA barcoding has revolutionized the field of taxonomy by providing an alternative, simple approach for species discrimination, where short sections of DNA, the cytochrome c oxidase subunit I (COI) gene in particular, are used as 'barcodes' to delineate species boundaries. In our study, we aimed to assess the effectiveness of two mitochondrial markers, the COI and 16S ribosomal deoxyribonucleic acid (16S rDNA) markers for DNA barcoding of P. canaliculata and P. maculata. The COI and 16S rDNA sequences of 40 Pomacea specimens collected from six localities in Peninsular Malaysia were analyzed to assess their barcoding performance using phylogenetic methods and distance-based assessments. The results confirmed both markers were suitable for barcoding P. canaliculata and P. maculata. The phylogenies of the COI and 16S rDNA markers demonstrated species-specific monophyly and were largely congruent with the exception of one individual. The COI marker exhibited a larger barcoding gap (6.06-6.58%) than the 16S rDNA marker (1.54%); however, the magnitude of barcoding gap generated within the barcoding region of the 16S rDNA marker (12-fold) was bigger than the COI counterpart (approximately 9-fold). Both markers were generally successful in identifying P. canaliculata and P. maculata in the similarity-based DNA identifications. The COI + 16S rDNA concatenated dataset successfully recovered monophylies of P. canaliculata and P. maculata but concatenation did not improve individual datasets in distance-based analyses. Overall, although both markers were successful for the identification of apple snails, the COI molecular marker is a better barcoding marker and could be utilized in various population genetic studies of P. canaliculata and P. maculata.
  6. Fulltext Algae Metabolites in Cosmeceutical: An Overview of Current Applications and Challenges
    Thiyagarasaiyar K, Goh BH, Jeon YJ, Yow YY
    Mar Drugs, 2020 Jun 19;18(6).
    PMID: 32575468 DOI: 10.3390/md18060323
    Cosmetics are widely used by people around the world to protect the skin from external stimuli. Consumer preference towards natural cosmetic products has increased as the synthetic cosmetic products caused adverse side effects and resulted in low absorption rate due to the chemicals' larger molecular size. The cosmetic industry uses the term "cosmeceutical", referring to a cosmetic product that is claimed to have medicinal or drug-like benefits. Marine algae have gained tremendous attention in cosmeceuticals. They are one of the richest marine resources considered safe and possessed negligible cytotoxicity effects on humans. Marine algae are rich in bioactive substances that have shown to exhibit strong benefits to the skin, particularly in overcoming rashes, pigmentation, aging, and cancer. The current review provides a detailed survey of the literature on cosmeceutical potentials and applications of algae as skin whitening, anti-aging, anticancer, antioxidant, anti-inflammation, and antimicrobial agents. The biological functions of algae and the underlying mechanisms of all these activities are included in this review. In addition, the challenges of using algae in cosmeceutical applications, such as the effectiveness of different extraction methods and processing, quality assurance, and regulations concerning extracts of algae in this sector were also discussed.
  7. Fulltext Decoding Antioxidant and Antibacterial Potentials of Malaysian Green Seaweeds: Caulerpa racemosa and Caulerpa lentillifera
    Yap WF, Tay V, Tan SH, Yow YY, Chew J
    Antibiotics (Basel), 2019 Sep 17;8(3).
    PMID: 31533237 DOI: 10.3390/antibiotics8030152
    Seaweeds are gaining a considerable amount of attention for their antioxidant and antibacterial properties. Caulerpa racemosa and Caulerpa lentillifera, also known as 'sea grapes', are green seaweeds commonly found in different parts of the world, but the antioxidant and antibacterial potentials of Malaysian C. racemosa and C. lentillifera have not been thoroughly explored. In this study, crude extracts of the seaweeds were prepared using chloroform, methanol, and water. Total phenolic content (TPC) and total flavonoid content (TFC) were measured, followed by in vitro antioxidant activity determination using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Antibacterial activities of these extracts were tested against Methicillin-resistant Staphylococcus aureus (MRSA) and neuropathogenic Escherichia coli K1. Liquid chromatography-mass spectrometry (LCMS) analysis was then used to determine the possible compounds present in the extract with the most potent antioxidant and antibacterial activity. Results showed that C. racemosa chloroform extract had the highest TPC (13.41 ± 0.86 mg GAE/g), antioxidant effect (EC50 at 0.65 ± 0.03 mg/mL), and the strongest antibacterial effect (97.7 ± 0.30%) against MRSA. LCMS analysis proposed that the chloroform extracts of C. racemosa are mainly polyunsaturated and monounsaturated fatty acids, terpenes, and alkaloids. In conclusion, C. racemosa can be a great source of novel antioxidant and antibacterial agents, but isolation and purification of the bioactive compounds are needed to study their mechanism of action.
  8. Anti-amoebic potential of azole scaffolds and nanoparticles against pathogenic Acanthamoeba
    Walvekar S, Anwar A, Anwar A, Sridewi N, Khalid M, Yow YY, et al.
    Acta Trop, 2020 Nov;211:105618.
    PMID: 32628912 DOI: 10.1016/j.actatropica.2020.105618
    Acanthamoeba spp. are free living amoeba (FLA) which are widely distributed in nature. They are opportunistic parasites and can cause severe infections to the eye, skin and central nervous system. The advances in drug discovery and modifications in the chemotherapeutic agents have shown little improvement in morbidity and mortality rates associated with Acanthamoeba infections. The mechanism-based process of drug discovery depends on the molecular drug targets present in the signaling pathways in the genome. Synthetic libraries provide a platform for broad spectrum of activities due to their desired structural modifications. Azoles, originally a class of synthetic anti-fungal drugs, disrupt the fungal cell membrane by inhibiting the biosynthesis of ergosterol through the inhibition of cytochrome P450 dependent 14α-lanosterol, a key step of the sterol pathway. Acanthamoeba and fungi share the presence of similar sterol intermediate, as ergosterol is also the major end-product in the sterol biosynthesis in Acanthamoeba. Sterols present in the eukaryotic cell membrane are one of the most essential lipids and exhibit important structural and signaling functions. Therefore, in this review we highlight the importance of specific targeting of ergosterol present in Acanthamoebic membrane by azole compounds for amoebicidal activity. Previously, azoles have also been repurposed to report antimicrobial, antiparasitic and antibacterial properties. Moreover, by loading the azoles into nanoparticles through advanced techniques in nanotechnology, such as physical encapsulation, adsorption, or chemical conjugation, the pharmacokinetics and therapeutic index of the drugs can be significantly improved. The current review proposes an important strategy to target Acanthamoeba using synthetic libraries of azoles and their conjugated nanoparticles for the first time.
  9. An Overview of Culinary and Medicinal Mushrooms in Neurodegeneration and Neurotrauma Research
    Wong KH, Ng CC, Kanagasabapathy G, Yow YY, Sabaratnam V
    Int J Med Mushrooms, 2017;19(3):191-202.
    PMID: 28605334 DOI: 10.1615/IntJMedMushrooms.v19.i3.10
    Culinary and medicinal mushrooms have been appreciated since prehistoric times as valuable resources for food and medicine. Edible mushrooms represent an untapped source of nutraceuticals and valuable palatable food. Long considered tonics, they are now treasured as functional foods that can improve human health and quality of life. Numerous studies have provided insights into the neuroprotective effects of edible mushrooms, which are attributed to their antioxidant, antineuroinflammatory, and cholinesterase inhibitory properties, and their ability to prevent neuronal death. Here we review the recent literature on the role of culinary and medicinal mushrooms in the management of neurodegenerative diseases and neurotrauma. We highlight some of the molecular mechanisms for how these alternative medicines provide health benefits that could help us to harness their neuroprotective effects.
  10. Fulltext Malaysian macroalga Padina australis Hauck attenuates high dose corticosterone-mediated oxidative damage in PC12 cells mimicking the effects of depression
    Subermaniam K, Yow YY, Lim SH, Koh OH, Wong KH
    Saudi J Biol Sci, 2020 Jun;27(6):1435-1445.
    PMID: 32489279 DOI: 10.1016/j.sjbs.2020.04.042
    Oxidative damage has been associated with the pathophysiology of depression. Macroalgae are equipped with antioxidant defense system to counteract the effects of free radicals. We explored the use of Malaysian Padina australis to attenuate high dose corticosterone-mediated oxidative damage in a cellular model mimicking depression. Fresh specimen of P. australis was freeze-dried and extracted sequentially with hexanes, ethyl acetate and ethanol. The extracts were screened for their phytochemical contents and antioxidant activities. Ethanol extract demonstrated the most potent antioxidant capacity and was selected for subsequent assays against high dose corticosterone of 600 µM-mediated oxidative damage in the rat pheochromocytoma (PC12) cells. The corticosterone reduced the cell viability, glutathione (GSH) level, aconitase activity, and mitochondrial membrane potential (MMP); and increased the lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) level and apoptosis. However, the extent of oxidative damage was reversed by 0.25-0.5 mg/mL ethanol extract suggesting a possible role of P. australis-based antioxidants in the mitochondrial defense against constant ROS generation and regulation of antioxidant pathway. The effects were similar to that of desipramine, a tricyclic antidepressant. Our findings indicate that P. australis can be developed as a mitochondria-targeted antioxidant to mitigate antidepressant-like effects.
  11. Fulltext Marine algae as emerging therapeutic alternatives for depression: A review
    Subermaniam K, Teoh SL, Yow YY, Tang YQ, Lim LW, Wong KH
    Iran J Basic Med Sci, 2021 Aug;24(8):997-1013.
    PMID: 34804417 DOI: 10.22038/ijbms.2021.54800.12291
    Depression is a complex heterogeneous brain disorder characterized by a range of symptoms, resulting in psychomotor and cognitive disabilities and suicidal thoughts. Its prevalence has reached an alarming level affecting millions of people globally. Despite advances in current pharmacological treatments, the heterogenicity of clinical response and incidences of adverse effects have shifted research focus to identification of new natural substances with minimal or no adverse effects as therapeutic alternatives. Marine algae-derived extracts and their constituents are considered potential sources of secondary metabolites with diverse beneficial effects. Marine algae with enormous health benefits are emerging as a natural source for discovering new alternative antidepressants. Its medicinal properties exhibited shielding efficacy against neuroinflammation, oxidative stress, and mitochondrial dysfunction, which are indicated to underlie the pathogenesis of many neurological disorders. Marine algae have been found to ameliorate depressive-like symptoms and behaviors in preclinical and clinical studies by restoring monoaminergic neurotransmission, hypothalamic-pituitary-adrenal axis function, neuroplasticity, and continuous neurogenesis in the dentate gyrus of the hippocampus via modulating brain-derived neurotrophic factors and antineuroinflammatory activity. Although antidepressant effects of marine algae have not been validated in comparison with currently available synthetic antidepressants, they have been reported to have effects on the pathophysiology of depression, thus suggesting their potential as novel antidepressants. In this review, we analyzed the currently available research on the potential benefits of marine algae on depression, including their effects on the pathophysiology of depression, potential clinical relevance of their antidepressant effects in preclinical and clinical studies, and the underlying mechanisms of these effects.
  12. CONJUGATION WITH SILVER NANOPARTICLES ENHANCES ANTI-ACANTHAMOEBIC ACTIVITY OF KAPPAPHYCUS ALVAREZII
    Walvekar S, Anwar A, Anwar A, Lai NJY, Yow YY, Khalid M, et al.
    J Parasitol, 2021 07 01;107(4):537-546.
    PMID: 34265050 DOI: 10.1645/21-41
    Nanomedicine has the potential in enhancing the efficacy and bioavailability of anti-infective agents. Here we determined whether conjugation of the Malaysian cultivated seaweed Kappaphycus alvarezii with silver-conjugated nanoparticles enhanced anti-acanthamoebic properties. Silver-conjugated K. alvarezii were successfully synthesized, followed by characterization with Fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometry, and transmission electron microscopy. Amoebicidal effects were evaluated against Acanthamoeba castellanii, and cytotoxicity assays were performed using HaCaT cells. Viability assays revealed that silver nanoparticles conjugated with K. alvarezii extract exhibited significant antiamoebic properties (P < 0.05). Nano-conjugates induced the production of reactive oxygen species. Importantly, silver-conjugated extract inhibited amoeba-mediated host cell damage as established by lactate dehydrogenase release. Neither the nano-conjugates nor the extract showed cytotoxicity against human cells in vitro. Liquid chromatography and mass spectroscopy revealed several molecules, including 2,6-nonadien-1-ol, N-desmethyl trifluoperazine, dulciol B, lucidumol A, acetoxolone, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, C16 sphinganine, 22-tricosenoic acid, and β-dihydrorotenone, of which dulciol B and C16 sphinganine are known to possess antimicrobial activities. In summary, marine organisms are an important source of bioactive molecules with anti-acanthamoebic properties that can be enhanced by conjugating with silver nanoparticles. Natural products combined with nanotechnology using multifunctional nanoparticle complexes can deliver therapeutic agents effectively and hold promise in the development of new formulations of anti-acanthamoebic agents.
  13. Fulltext Malaysian brown macroalga Padina australis mitigates lipopolysaccharide-stimulated neuroinflammation in BV2 microglial cells
    Subermaniam K, Lew SY, Yow YY, Lim SH, Yu WS, Lim LW, et al.
    Iran J Basic Med Sci, 2023;26(6):669-679.
    PMID: 37275754 DOI: 10.22038/IJBMS.2023.67835.14842
    OBJECTIVES: Neuroinflammation and microglial activation are pathological features in central nervous system disorders. Excess levels of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in exacerbation of neuronal damage during chronic activation of microglial cells. Padina australis, a brown macroalga, has been demonstrated to have various pharmacological properties such as anti-neuroinflammatory activity. However, the underlying mechanism mediating the anti-neuroinflammatory potential of P. australis remains poorly understood. We explored the use of Malaysian P. australis in attenuating lipopolysaccharide (LPS)-stimulated neuroinflammation in BV2 microglial cells.

    MATERIALS AND METHODS: Fresh specimens of P. australis were freeze-dried and subjected to ethanol extraction. The ethanol extract (PAEE) was evaluated for its protective effects against 1 µg/ml LPS-stimulated neuroinflammation in BV2 microglial cells.

    RESULTS: LPS reduced the viability of BV2 microglia cells and increased the levels of nitric oxide (NO), prostaglandin E2 (PGE2), intracellular reactive oxygen species (ROS), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). However, the neuroinflammatory response was reversed by 0.5-2.0 mg/ml PAEE in a dose-dependent manner. Analysis of liquid chromatography-mass spectrometry (LC-MS) of PAEE subfractions revealed five compounds; methyl α-eleostearate, ethyl α-eleostearate, niacinamide, stearamide, and linoleic acid.

    CONCLUSION: The protective effects of PAEE against LPS-stimulated neuroinflammation in BV2 microglial cells were found to be mediated by the suppression of excess levels of intracellular ROS and pro-inflammatory mediators and cytokines, denoting the protective role of P. australis in combating continuous neuroinflammation. Our findings support the use of P. australis as a possible therapeutic for neuroinflammatory and neurodegenerative diseases.

  14. Fulltext A scaffolded approach to unearth potential antibacterial components from epicarp of Malaysian Nephelium lappaceum L
    Asghar A, Tan YC, Zahoor M, Zainal Abidin SA, Yow YY, Khan E, et al.
    Sci Rep, 2021 Jul 05;11(1):13859.
    PMID: 34226594 DOI: 10.1038/s41598-021-92622-0
    The emergence and spread of antimicrobial resistance have been of serious concern to human health and the management of bacterial infectious diseases. Effective treatment of these diseases requires the development of novel therapeutics, preferably free of side effects. In this regard, natural products are frequently conceived to be potential alternative sources for novel antibacterial compounds. Herein, we have evaluated the antibacterial activity of the epicarp extracts of the Malaysian cultivar of yellow rambutan fruit (Nephelium lappaceum L.) against six pathogens namely, Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella enterica. Among a series of solvent extracts, fractions of ethyl acetate and acetone have revealed significant activity towards all tested strains. Chemical profiling of these fractions, via HPLC, LC-MS and GC-MS, has generated a library of potentially bioactive compounds. Downstream virtual screening, pharmacological prediction, and receptor-ligand molecular dynamics simulation have eventually unveiled novel potential antibacterial compounds, which can be extracted for medicinal use. We report compounds like catechin, eplerenone and oritin-4-beta-ol to be computationally inhibiting the ATP-binding domain of the chaperone, DnaK of P. aeruginosa and MRSA. Thus, our work follows the objective to propose new antimicrobials capable of perforating the barrier of resistance posed by both the gram positives and the negatives.
  15. Fulltext Genetic and morphological analyses of Gracilaria firma and G. changii (Gracilariaceae, Rhodophyta), the commercially important agarophytes in western Pacific
    Ng PK, Lin SM, Lim PE, Hurtado AQ, Phang SM, Yow YY, et al.
    PLoS One, 2017;12(7):e0182176.
    PMID: 28759629 DOI: 10.1371/journal.pone.0182176
    Many studies classifying Gracilaria species for the exploitation of agarophytes and the development of the agar industry were conducted before the prevalence of molecular tools, resulting in the description of many species based solely on their morphology. Gracilaria firma and G. changii are among the commercially important agarophytes from the western Pacific; both feature branches with basal constrictions that taper toward acute apices. In this study, we contrasted the morpho-anatomical circumscriptions of the two traditionally described species with molecular data from samples that included representatives of G. changii collected from its type locality. Concerted molecular analyses using the rbcL and cox1 gene sequences, coupled with morphological observations of the collections from the western Pacific, revealed no inherent differences to support the treatment of the two entities as distinct taxa. We propose merging G. changii (a later synonym) into G. firma and recognize G. firma based on thallus branches with abrupt basal constrictions that gradually taper toward acute (or sometimes broken) apices, cystocarps consisting of small gonimoblast cells and inconspicuous multinucleate tubular nutritive cells issuing from gonimoblasts extending into the inner pericarp at the cystocarp floor, as well as deep spermatangial conceptacles of the verrucosa-type. The validation of specimens under different names as a single genetic species is useful to allow communication and knowledge transfer among groups from different fields. This study also revealed considerably low number of haplotypes and nucleotide diversity with apparent phylogeographic patterns for G. firma in the region. Populations from the Philippines and Taiwan were divergent from each other as well as from the populations from Malaysia, Thailand, Singapore and Vietnam. Establishment of baseline data on the genetic diversity of this commercially important agarophyte is relevant in the context of cultivation, as limited genetic diversity may jeopardize the potential for its genetic improvement over time.
  16. Synergistic effects of starch and carrageenan from Kappaphycus alvarezii in composite film formation: Physicochemical and degradable properties
    Yap XY, Khalid M, Raju G, Gew LT, Yow YY
    Int J Biol Macromol, 2024 Sep 07.
    PMID: 39256129 DOI: 10.1016/j.ijbiomac.2024.135205
    Rising concerns around plastic pollution from single-use plastic (SUPs), especially food packaging, have driven interest in sustainable alternatives. As such, algae biomass has gained attention for bioplastic production due to algae's rapid growth and abundant polysaccharides. This research focuses on extracting carrageenan from Kappaphycus alvarezii, extensively cultivated in Sabah, Malaysia, and utilizing it in combination with starch and glycerol to develop algae-based films. The physicochemical properties and degradation rate of these films were evaluated, revealing that the addition of carrageenan enhanced overall thermal stability meanwhile increasing water solubility, water content but reducing the degradation rate and swelling degree. This is primarily due to the crystalline structures of carrageenan, which provide a more rigid arrangement compared to the network of starch polymers. However, the incorporation of starch into the blends has enhanced the elongation and surface morphology, resulting in more balanced properties. Overall, these carrageenan films displayed impressive thermal, mechanical, and biodegradability characteristics, establishing their viability as substitutes for conventional plastics.
  17. Fulltext Streptomyces sp. MUM273b: A mangrove-derived potential source for antioxidant and UVB radiation protectants
    Tan LT, Mahendra CK, Yow YY, Chan KG, Khan TM, Lee LH, et al.
    Microbiologyopen, 2019 10;8(10):e859.
    PMID: 31199601 DOI: 10.1002/mbo3.859
    Microbial natural products serve as a good source for antioxidants. The mangrove-derived Streptomyces bacteria have been evidenced to produce antioxidative compounds. This study reports the isolation of Streptomyces sp. MUM273b from mangrove soil that may serve as a promising source of antioxidants and UV-protective agents. Identification and characterization methods determine that strain MUM273b belongs to the genus Streptomyces. The MUM273b extract exhibits antioxidant activities, including DPPH, ABTS, and superoxide radical scavenging activities and also metal-chelating activity. The MUM273b extract was also shown to inhibit the production of malondialdehyde in metal-induced lipid peroxidation. Strong correlation between the antioxidant activities and the total phenolic content of MUM273b extract was shown. In addition, MUM273b extract exhibited cytoprotective effect on the UVB-induced cell death in HaCaT keratinocytes. Gas chromatography-mass spectrometry analysis detected phenolics, pyrrole, pyrazine, ester, and cyclic dipeptides in MUM273b extract. In summary, Streptomyces MUM273b extract portrays an exciting avenue for future antioxidative drugs and cosmeceuticals development.
  18. Fulltext Therapeutic Potential of Complementary and Alternative Medicines in Peripheral Nerve Regeneration: A Systematic Review
    Yow YY, Goh TK, Nyiew KY, Lim LW, Phang SM, Lim SH, et al.
    Cells, 2021 08 25;10(9).
    PMID: 34571842 DOI: 10.3390/cells10092194
    Despite the progressive advances, current standards of treatments for peripheral nerve injury do not guarantee complete recovery. Thus, alternative therapeutic interventions should be considered. Complementary and alternative medicines (CAMs) are widely explored for their therapeutic value, but their potential use in peripheral nerve regeneration is underappreciated. The present systematic review, designed according to guidelines of Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, aims to present and discuss the current literature on the neuroregenerative potential of CAMs, focusing on plants or herbs, mushrooms, decoctions, and their respective natural products. The available literature on CAMs associated with peripheral nerve regeneration published up to 2020 were retrieved from PubMed, Scopus, and Web of Science. According to current literature, the neuroregenerative potential of Achyranthes bidentata, Astragalus membranaceus, Curcuma longa, Panax ginseng, and Hericium erinaceus are the most widely studied. Various CAMs enhanced proliferation and migration of Schwann cells in vitro, primarily through activation of MAPK pathway and FGF-2 signaling, respectively. Animal studies demonstrated the ability of CAMs to promote peripheral nerve regeneration and functional recovery, which are partially associated with modulations of neurotrophic factors, pro-inflammatory cytokines, and anti-apoptotic signaling. This systematic review provides evidence for the potential use of CAMs in the management of peripheral nerve injury.
  19. Fulltext Algae-Derived Anti-Inflammatory Compounds against Particulate Matters-Induced Respiratory Diseases: A Systematic Review
    Tan PX, Thiyagarasaiyar K, Tan CY, Jeon YJ, Nadzir MSM, Wu YJ, et al.
    Mar Drugs, 2021 May 30;19(6).
    PMID: 34070821 DOI: 10.3390/md19060317
    Air pollution has recently become a subject of increasing concern in many parts of the world. The World Health Organization (WHO) estimated that nearly 4.2 million early deaths are due to exposure to fine particles in polluted air, which causes multiple respiratory diseases. Algae, as a natural product, can be an alternative treatment due to potential biofunctional properties and advantages. This systematic review aims to summarize and evaluate the evidence of metabolites derived from algae as potential anti-inflammatory agents against respiratory disorders induced by atmospheric particulate matter (PM). Databases such as Scopus, Web of Science, and PubMed were systematically searched for relevant published full articles from 2016 to 2020. The main key search terms were limited to "algae", "anti-inflammation", and "air pollutant". The search activity resulted in the retrieval of a total of 36 publications. Nine publications are eligible for inclusion in this systematic review. A total of four brown algae (Ecklonia cava, Ishige okamurae, Sargassum binderi and Sargassum horneri) with phytosterol, polysaccharides and polyphenols were reported in the nine studies. The review sheds light on the pathways of particulate matter travelling into respiratory systems and causing inflammation, and on the mechanisms of actions of algae in inhibiting inflammation. Limitations and future directions are also discussed. More research is needed to investigate the potential of algae as anti-inflammatory agents against PM in in vivo and in vitro experimental models, as well as clinically.
  20. Fulltext A comprehensive review on ethnomedicinal uses, phytochemistry, toxicology, and pharmacological activities of Dittrichia viscosa (L.) Greuter
    Jerada R, Er-Rakibi A, Cherkani Hassani A, Benzeid H, El Ouardi A, Harhar H, et al.
    J Tradit Complement Med, 2024 Jul;14(4):355-380.
    PMID: 39035692 DOI: 10.1016/j.jtcme.2024.03.012
    Dittrichia viscosa is a perennial herb that has been used for generations in traditional medicine to address a variety of diseases, including diabetes, hypertension, cancer, microbial disorders, inflammatory conditions, and wound healing. The objective of this review is to provide an overview of existing knowledge on D. viscosa with regards to its botanical description, ethnomedicinal uses, and pharmacological properties. Databases such as Scopus, Wiley-Online, PubMed, Springer, Google Scholar, and ScienceDirect were used to select relevant articles based on their title and abstract. The reviewed studies found a strong correlation between D. viscosa's traditional uses and its observed biological effects. Pharmacological research has shown that the essential oils and extracts from D. viscosa possess a variety of biological activities, such as anti-inflammatory, anticancer, antibacterial, antifungal, analgesic, and antioxidant properties. The chemical compounds found in D. viscosa include sesquiterpenes, monoterpenes, flavonoids, and phenolic acids; some of these compounds, such as tometosin and inuviscolide, have been isolated and displayed promising cytotoxic and anti-inflammatory activity. The present review suggests that the pharmacological properties of D. viscosa align well with its ethnomedicinal uses. These findings support the traditional use of D. viscosa in treating various illnesses. Additionally, toxicological examinations of D. viscosa extracts and essential oil have demonstrated the plant's safety, which supports the need for comprehensive pharmacological studies, in vivo studies, and clinical trials to evaluate the best doses for optimal medicinal effects. This work underscores the medicinal value of D. viscosa and its potential in developing new pharmacological agents to address major health challenges like antibiotic resistance and cancers.
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