Antitubercular and Antibacterial Activity of Quinonoid Natural Products Against Multi‐Drug Resistant Clinical Isolates

Abstract

Multi-drug resistant Mycobacterium tuberculosis and other bacterial pathogens represent a major threat to human health. In view of the critical need to augment the current drug regime, we have investigated therapeutic potential of five quinonoids, viz. emodin, diospyrin, plumbagin, menadione and thymoquinone, derived from natural products. The antimicrobial activity of quinonoids was evaluated against a broad panel of multi-drug and extensively drug-resistant tuberculosis (M/XDR-TB) strains, rapid growing mycobacteria and other bacterial isolates, some of which were producers of β-lactamase, Extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, metallo-beta-lactamase (MBL) enzymes, as well as their drug-sensitive ATCC counterparts. All the tested quinones exhibited antimycobacterial and broad spectrum antibacterial activity, particularly against M. tuberculosis (lowest MIC 0.25 µg/mL) and Gram-positive bacteria (lowest MIC <4 µg/mL) of clinical origin. The order of antitubercular activity of the tested quinonoids was plumbagin > emodin ~ menadione ~ thymoquinone > diospyrin, whereas their antibacterial efficacy was plumbagin > menadione ~ thymoquinone > diospyrin > emodin. Furthermore, this is the first evaluation performed on these quinonoids against a broad panel of drug-resistant and drug-sensitive clinical isolates, to the best of our knowledge.

Improved micropropagation of Bacopa monnieri (L.) Wettst. (Plantaginaceae) and antimicrobial activity of in vitro and ex vitro raised plants against multidrug-resistant clinical isolates of urinary tract infecting (UTI) and respiratory tract infecting (RTI) bacteria

“…Only Hema et al [13] had described the antimicrobial property of B. monnieri against clinical isolates of human pathogenic strains, but these are not MDR strains. Antibacterial resistance has become one of the grave public health concerns, globally, over the last two decades [14,15]. Particularly, MDR is a major concern in present day medical science.…”

“…Although one report are available where clinical isolates of human pathogenic strains are tested, but these are not multidrug-resistant (MDR) strains [13]. Antibacterial resistance has become one of the grave public health concerns, globally, over the last two decades [14,15]. In modern years, there has been a rising interest in investigating and evolving new antimicrobial agents from various sources to combat microbial resistance [16].…”

Anti-tubercular substances produced by plants

“…Its MIC is between 0.25-31 µg/ml, which is very low for the plant. Diospyrin from the stem bark of Diospyros montana and emodin from the stem bark of Ventilago madraspatana were tested by the same team of researchers and displayed good antitubercular activity, even against MDR and XDR strains [18]. Another plant which was multifaceted tested is Psidium guineense.…”

Organic Cultivation of Tomato in India with Recycled Slaughterhouse Wastes: Evaluation of Fertilizer and Fruit Safety

“…Undiluted sample was decontaminated by N-acetyl-L-cysteine-soduium hydroxide method [72]. Decontaminated sample (500 μL) was aseptically injected under vacuum to the BacT/ALERT MP bottle which contained 10 mL of aqueous media (Middlebrook 7H9 broth, pancreatic digest of casein, bovine serum albumin and catalase) and incubated in the BacT/ALERT 3D Mycobacteria Detection System at 37 °C for 42 days.…”