Increasing incidences of acne and skin infections, antibiotic resistance, and side effects associated with synthetic dermatology have necessitated the need for safe, sustainable treatment approaches. This work describes the environmentally friendly preparation of Zinc Oxide Nanoparticles (ZnO NPs) through green chemistry by utilizing the leaf extract of Acalypha indica L. plant and further applying the nanoparticles in the preparation of nanogel, herbal soap, and face serum. The biosynthesized zinc oxide nanoparticles were analysed using UV-Visible spectroscopy, Fourier Transform Infra-red (FTIR), X-Ray diffraction (XRD), and Scanning electron microscopy (SEM). From UV-Visible spectra, an excitonic absorption band peak was observed at 384 nm, which confirms the presence of nanoparticles. FTIR spectra show a vibrational peak of Zn-O bonds at 476 cm⁻¹ and 512 cm⁻¹ as well as surface-bonded phenolic, aliphatic, and carbonyl functional groups due to flavonoids, terpenoids, and tannins. XRD confirmed a highly crystalline hexagonal wurtzite structure (JCPDS No. 36-1451) with an average crystallite size of 18.5 ± 3.2 nm. SEM revealed polydisperse, moderately agglomerated nanoparticles with irregular, porous morphology. ZnO NPs displayed strong bactericidal action against nine clinical strains of bacteria, with the highest zone of inhibition observed as 25 mm against Staphylococcus aureus and Salmonella typhi at 75 µg/well concentration. These particles were also found to possess excellent radical scavenging ability, IC₅₀ being recorded as 62.4 ± 2.1 µg/mL for DPPH free radical. The pH of all the three preparations was compatible with the skin, viz., 5–6. Also, these formulations were physically stable and had good spreadability, i.e., nanogel preparation – 28 mm; soap preparation – 47 mm; serum preparation – 21 mm at 150 g. The herbal soap proved ideal for daily hygiene, while the serum enabled rapid spot treatment. This study establishes that Acalypha indica-mediated green synthesis produces stable, crystalline, multifunctional ZnO nanoparticles with substantial antimicrobial and antioxidant properties. The nanogel formulation represents a scalable, cost-effective, natural-origin alternative for acne and skin infection management, addressing antibiotic resistance and synthetic chemical toxicity.
Kesavardhini et al. (Sat,) studied this question.