BIOACTIVE COMPOUNDS IN CURCUMA LONGA EXTRACTS: POTENTIAL INHIBITORS OF MULTIDRUG-RESISTANT KLEBSIELLA SPP.

Abstract

This study evaluated the inhibitory effects of turmeric (Curcuma longa) extracts against selected multidrug-resistant Klebsiella spp. Freshly ground C. longa was extracted using the maceration method, and the susceptibility of the organisms to the extract was tested using the agar well diffusion technique. Gas chromatography-mass spectrometry (GC-MS) was employed to identify the bioactive compounds in the extract. Molecular docking was performed using the Glide module of Maestro Schrödinger to predict binding affinities and interaction modes of C. longa phytochemicals with SHV-1 (beta-lactamase-1) of K. pneumoniae and NpsA (phosphoribosyltransferase) of K. oxytoca. The inhibition zones of C. longa extract against the antibiotic-resistant Klebsiella spp. ranged from 17±0.88 mm to 18.67±0.88 mm. The minimum inhibitory concentration (MIC) of the extract against the test organisms ranged from 25 mg/ml to 50 mg/ml, while the maximum bactericidal concentration (MBC) was 100 mg/ml. GC-MS analysis identified 31 compounds in the C. longa extract, with the main components being n-Hexadecanoic acid (9.14%), methyl tetradecanoate (7.77%), octadecanamide (7.74%), maltose (7.74%), and phytol (7.45%). Molecular docking analyses identified C. longa phytochemicals with strong inhibitory potential against SHV-1 in Klebsiella pneumoniae and NpsA in K. oxytoca. 1,2-Benzenedicarboxylic acid, diheptyl ester showed the highest binding scores (−8.641 and −9.765 kcal/mol), while other compounds exhibited stable interactions and favorable pharmacokinetic profiles, outperforming standard antibiotics. These findings suggest that C. longa extract could be a promising alternative for combating infections caused by antibiotic-resistant Klebsiella spp.