Green Synthesis and Physicochemical Characterization of Platinum Nanoparticles Using Anisochilus Scaber Benth Leaf Extract: Antioxidant And Antidiabetic Activities

Abstract

Developing an economically viable and environmentally sustainable method for the
preparation of metallic nanoparticles remains a priority within the expanding area of
nanobiotechnology. The present study reports a simple, reagent free plant mediated synthesis
of platinum nanoparticles (PtNPs) using leaf extract obtained from Anisochilus scaber Benth
(family: Lamiaceae) as a dual reducing and capping agent. The obtained nanoparticles were
comprehensively investigated for their physicochemical characteristics, antioxidant activity
and antidiabetic potential. The formation of PtNPs was verified through UV–Visible analysis,
XRD analysis, FTIR analysis, SEM analysis, TEM analysis, DLS analysis, zeta potential
measurement, and EDX analysis. Antioxidant potential was evaluated by employing DPPH,
ABTS, FRAP, H₂O₂ radical scavenging, and NO radical scavenging assays. Antidiabetic
potential was evaluated through in vitro inhibition of α-amylase, α-glucosidase, and β-
glucosidase enzymes. UV–Vis analysis showed a distinct absorption peak at 240 nm. XRD
analysis revealed the cubic crystalline structure with diffraction peaks at 2θ = 39.6°, 46.2°, and
67° (JCPDS card No. 01-1190). TEM showed an average core diameter of approximately 94
nm, with a DLS hydrodynamic size of 126 nm (PDI = 0.268). The resulting nanoparticles
showed a remarkable zeta potential value of −63.4 mV, reflecting exceptional colloidal
stability. EDX confirmed platinum as the predominant elemental constituent (83.18 wt%). The
PtNPs demonstrated broad-spectrum, concentration-dependent antioxidant activity, with
DPPH IC₅₀ = 95.50 μg/ml, H₂O₂ IC₅₀ = 71.74 μg/ml, ABTS IC₅₀ = 81.60 μg/ml, and NO IC₅₀ =
82.91 μg/ml. Antidiabetic inhibition IC₅₀ values were determined as 69.11 μg/ml (α-amylase),
56.35 μg/ml (α-glucosidase), and 48.26 μg/ml (β-glucosidase). This study establishes
Anisochilus scaber Benth as a potent and previously underexplored phytochemical resource
for the green fabrication of colloidally stable PtNPs with significant antioxidant and
antidiabetic potential, contributing a novel plant nanoparticle system to the nanobiotechnology
literature.