Antibacterial Properties of Curcuma longa Crude Extract-Induced Silver Nanoparticles against Isolates from Diabetic Patients with Foot Infections
Abstract:
Curcuma longa has a long history of traditional use for treating ulcers, hepatic disorders, wound healing, and improving glucose control. This study aimed to assess the phytochemical compositions (both quantitative and qualitative) and antibacterial properties of crude extracts of C. longa. Additionally, the study involved the synthesis and characterization of silver nanoparticles using these extracts and evaluated their antibacterial and wound healing activities.
Quantitative analysis revealed significant amounts of phytates (6577.9 mg/100 g), cyanides (2741.8 mg/100 g), and saponins (618.0 mg/100 g) in the plant material. Cold maceration of the rhizomes with 70% ethanol yielded a crude extract (E), which was further partitioned into chloroform (Ec), ethyl acetate (Eea) soluble fractions, and an aqueous residual fraction (Eaq). Qualitative screening of these fractions indicated the presence of flavonoids, reducing sugars, anthraquinones, tannins, and saponins.
The antibacterial activity of the crude extracts and extract-mediated silver nanoparticles (AgNPs) from C. longa rhizomes was assessed against isolates from patients with diabetic foot infection using the agar well diffusion method. Results showed that the extract and its fractions at 100 mg/ml were inactive against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus. However, the Eea fraction at 200 mg/ml exhibited activity against P. aeruginosa, E. coli, and S. pyogenes.
The synthesized silver nanoparticles (E-AgNPs, Ec-AgNPs, Eea-AgNPs, and Eaq-AgNPs) had respective wavelengths of 405 nm, 406 nm, 409 nm, and 410 nm. Fourier Transform Infrared Spectroscopy (FTIR) indicated the presence of aromatic, alkanes, alkynes, alkenes, and carboxylic functional groups, while Scanning Electron Microscopy (SEM) showed clustered rod-like morphology for Eea-AgNPs. The highest X-ray diffraction (XRD) peak was observed at 2ϴ (340).
The Eea-AgNPs at 200 mg/ml demonstrated antibacterial activity against S. pyogenes, P. aeruginosa, E. coli, and K. pneumoniae, with zones of inhibition of 7 ± 1.7 mm, 10 ± 0.7 mm, 11 ± 1.1 mm, and 14 ± 0.5 mm, respectively. The minimum inhibitory concentration (MIC) of Eea-AgNPs against test isolates was found to be 12.5 mg/ml, and the extract exhibited bacteriostatic properties against the tested isolates.
In a rat model, the topical application of Eea-AgNPs ointment led to significant (P<0.05) wound closure, as observed from Day 0 (1.24 ± 0.00 mm to 1.29 ± 0.19 mm) to Day 14 (0.4 ± 0.1 mm to 0.73 ± 0.00 mm), compared to a control group (Diabetes + Wound only) (1.23 ± 0.00 to 1.1 ± 0.3 mm). Histological analysis of the treated rats indicated wound healing characterized by collagens, fibroblasts, inflammatory cells, new blood vessels, granulation tissues, and complete epithelialization. Moreover, the application of the ointment did not cause any allergic reactions, rashes, or skin irritation in the rats.
These findings highlight the potential of C. longa as a safe therapeutic agent for treating and healing infected ulcers.
Antibacterial Properties of Curcuma longa Crude Extract-Induced Silver Nanoparticles against Isolates from Diabetic Patients with Foot Infections