Ramar Dharmaraj

Mr. Ramar Dharmaraj

orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

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

Representative Publications

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11 April 2025 in Inorganic Chemistry Communications
Verified
Journal Article
Closed access
NSNattan Stalin
Nattan Stalin
Ramar DharmarajRamar Dharmaraj
Ramar Dharmaraj
MEMasanam Esakkirajan
Masanam Esakkirajan
VAVimalanathan ArunPrasanna
Vimalanathan ArunPrasanna
AAAyyakannu Arumugam
Ayyakannu Arumugam
KGKasi Gopinath
Kasi Gopinath

13 August 2025 in Natural and Life Sciences Communications
Verified
Journal Article
Closed access
GKGopinath Kasi
Gopinath Kasi
BVBalamurugan Venkatachalam
Balamurugan Venkatachalam
STSarinthip Thanakkasaranee
Sarinthip Thanakkasaranee
NSNattan Stalin
Nattan Stalin
Ramar DharmarajRamar Dharmaraj
Ramar Dharmaraj
Pornchai RachtanapunPornchai Rachtanapun
Pornchai Rachtanapun
This study aimed to compare the bioactive profiles and biological activities of methanolic extracts from Curcuma aromatica (CA) and Curcuma longa (CL) rhizomes. Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analyses revealed the presence of bioactive functional groups and identified 19 and 14 phytocompounds in the CA and CL extracts, respectively. The CL extract exhibited higher flavonoid, alkaloid, and phenol contents, along with superior antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays, while CA showed greater metal-chelating activity. The CL extract showed strong antimicrobial activity against Streptococcus pneumoniae and Klebsiella pneumoniae (1.46 cm inhibition zone), while the CA extract exhibited no antimicrobial efficacy. Silver nanoparticles (Ag NPs) synthesized using CL extract displayed an ultraviolet-visible (UV-Vis) absorption peak at 410 nm, spherical morphology, and a face-centered cubic structure with an average crystallite size of 9.32 nm. These Ag NPs exhibited dose-dependent antimicrobial activity against Bacillus megaterium, S. pneumoniae, and K. pneumoniae at a concentration of 100 µg/mL. In vivo toxicity studies of Ag NPs revealed 26.33–76.33% mortality in Artemia salina nauplii at 10 mg/mL after 24 h, while an in vitro cell viability assay in RAW 264.7 cells at 1 µg/mL confirmed cytocompatibility with a stimulatory hormesis effect. These findings suggest that CL extract acts as an antioxidant and antimicrobial agent. The CL extract-mediated synthesis of Ag NPs can be used in antimicrobial coatings, wound dressings, and topical ointments to prevent and treat infections

30 June 2026 in Polymers
Verified
Journal Article
Open access
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GOPINATH KASIGOPINATH KASI
GOPINATH KASI
Sarinthip ThanakkasaraneeSarinthip Thanakkasaranee
Sarinthip Thanakkasaranee
Nattan StalinNattan Stalin
Nattan Stalin
TPTae-Sik Park
Tae-Sik Park
Ramar DharmarajRamar Dharmaraj
Ramar Dharmaraj
Pornchai RachtanapunPornchai Rachtanapun
Pornchai Rachtanapun
Polylactic acid (PLA)-curcumin (CCM) composites, incorporating various contents of surface-functionalized dual-metal-doped copper oxide (SF-M-CuO), were prepared by the solution casting method. Synthesized composite films were evaluated for their antioxidant, biocompatible, photothermal, and antibacterial properties. The 4% CCM exhibits excellent compatibility based on total color difference, antioxidant activity, and controlled curcumin release behavior. In addition, different contents of SF-M-CuO (1–4%) were added to the PLA-4%-CCM polymer matrix. Synthesized composite films were characterized through functional, structural, and topographical analyses. FTIR and XRD analyses confirmed the successful incorporation of CCM and SF-M-CuO into the PLA matrix, which enhanced interfacial interactions and increased the crystallinity index by acting as effective nucleating agents. ABTS and DPPH radical scavenging assays revealed dose-dependent antioxidant activity due to the synergistic effects of CCM and SF-M-CuO. Biocompatibility evaluation using RAW 264.7 macrophage cells demonstrated non-toxic responses and enhanced cell proliferation in PLA-4%-CCM composite films containing up to 3%-SF-M-CuO. Among the fabricated films, PLA-4%-CCM-3%-SF-M-CuO exhibited superior photothermal performance and excellent antibacterial activity against Staphylococcus aureus and Escherichia coli, reducing bacterial counts to below the limit of detection. These findings demonstrate the potential of PLA-4%-CCM-3%-SF-M-CuO composite films as sustainable multifunctional materials for food safety and biomedical applications.