Mayan Medicinal Plants Bignonia potosina and Thouinia paucidentata Demonstrate Anti-Infective Properties Against the Priority Antibiotic-Resistant Bacteria Acinetobacter baumannii and Pseudomonas aeruginosa

Abstract

(1) Background: Carbapenem-resistant Acinetobacter baumannii (CBRAB) and Pseudomonas aeruginosa (CBRPA) are critical and high-priority pathogens that require new therapeutic developments. Medicinal plants are valuable pharmaceutical resources. This study explored the anti-infective properties of Mayan plants, Bignonia potosina, and Thouinia paucidentata. (2) Methods: Plant parts were extracted using n-hexane, and their ability to inhibit bacterial growth and counteract resistance mechanisms and virulence factors in CBRAB and CBRPA was assessed. GC-MS analysis of the composition of the non-polar extracts and chemometric techniques correlated the phytoconstituents with anti-infective properties. (3) Results: Bignonia potosina liana and flower extracts exhibited potent antibacterial activity against A. baumannii strains (MIC 15.7 to 250 µg/mL) and moderate activity against P. aeruginosa strains (MIC 250 to 1000 µg/mL). Thouinia paucidentata leaf extract at 1000 µg/mL reduced imipenem MIC by 2048-fold for CBRAB, and B. potosina flower extract significantly inhibited A. baumannii catalase activity (at 62.5 µg/mL) and reduced P. aeruginosa pyocyanin production (at 1000 µg/mL). Chemometric analysis identified fatty acids, fatty acid amides, terpenes, and higher alkanes as contributors to their anti-infective properties. (4) Conclusions: This study highlights the potential of medicinal plants in the development of novel anti-infective therapies against CBRAB and CBRPA with various targets.

Keywords: Acinetobacter baumannii; Bignonia potosina; Pseudomonas aeruginosa; Thouinia paucidentata; anti-resistance; anti-virulence; antibacterial; efflux pump; pyocyanin.

Figure 1

Anti-biofilm activity of Bignonia potosina and Thouinia paucidentata n-Hex extracts against strong biofilm-producing CBRAB (UIMY-ABA-81). Values ± SD with the same letter showed non-significant differences in the post hoc Tukey test (p < 0.05). From B. potosina: BPLi: n-Hex liana extract; BPF: n-Hex flower extract; BPL: n-Hex leaf extract. From T. paucidentata TPB: n-Hex bark extract; TPL: n-Hex leaf extract.

Figure 2

Anti-biofilm activity of Bignonia potosina and Thouinia paucidentata extracts against strong biofilm-producing CBRPA (Pseudomonas aeruginosa ATCC-35032) at sub-inhibitory concentrations. Values ± SD with the same letter showed non-significant differences in the post hoc Tukey test (p < 0.05). From B. potosina: BPLi: n-Hex liana extract; BPF: n-Hex flower extract; BPL: n-Hex leaf extract. From T. paucidentata TPB: n-Hex bark extract; TPL: n-Hex leaf extract.

Figure 3

Effect of Bignonia potosina and Thouinia paucidentata extracts on CBRAB UIMY-ABA-205 after treatment with H₂O₂. Values ± SD with the same letter showed non-significant differences in the post hoc Tukey test (p < 0.05). From B. potosina: BPLi: n-Hex liana extract; BPF: n-Hex flower extract; BPL: n-Hex leaf extract. From T. paucidentata TPB: n-Hex bark extract; TPL: n-Hex leaf extract; AZT: azithromycin.

Figure 4

Effect of Bignonia potosina and Thouinia paucidentata extracts on the production of pyocyanin of CBRPA PAE-ATCC-35032. Values ± SD with the same letter showed non-significant differences in the post hoc Tukey test (p < 0.05). From B. potosina: BPLi: n-Hex liana extract; BPF: n-Hex flower extract; BPL: n-Hex leaf extract. From T. paucidentata TPB: n-Hex bark extract; TPL: n-Hex leaf extract; AZT: azithromycin.

Figure 5

(a) Scores and loading plots from the PLS-DA model for activity on bacterial growth. MIC values of n-Hex extracts from Bignonia potosina and Thouinia paucidentata against CBRAB and CBRPA strains according to this categorical classification: 1000 µg/mL: low activity; 500–250 µg/mL: moderate activity; 125–62.5 µg/mL: high activity; <62.5 µg/mL: very high activity. (b) Scores and loadings plot from the PLS-DA model for antibiotic-modulation activity according to this categorical classification: 2–4 of AMF: low activity; 8–16 of FMA: moderate activity; >128 of FMA very high activity. (c) Scores and loadings plot from PLS-DA model for antivirulence activity according to this categorical classification: % inhibition > 50%: active. Phytoconstituents in green are associated with anti-infective properties. BPLi: n-Hex liana extract of B. potosina; BPF: n-Hex flower extract B. potosina; BPL: n-Hex leaf extract B. potosina; TPB: n-Hex bark extract of T. paucidentata; TPL: n-Hex leaf extract of T. paucidentata.