Fruits of Prosopis chilensis and Tetrapleura tetraptera as an alternative against multi-resistant bacteria in lower respiratory tract infections

Pseudomonas aeruginosa is a bacterium whose global spread poses a significant threat to human health due to its multidrug resistance (MDR). As a result, it is crucial to explore alternative treatments, particularly plant-based drugs, that are considered safe. The fruits of two plants, Tetrapleura tetraptera, and Prosopis chilensis, have been traditionally used to treat infectious diseases. These fruits are well-known for their nutritional and functional properties and their various bioactive compounds. Given these characteristics, the fruits can be effectively used against bacterial species like P. aeruginosa, which are resistant to conventional antibiotics. The present study aimed to evaluate the effects of fruit extracts on the multi-resistant bacterium P. aeruginosa PAO1. The research utilized methanolic, hydro-methanolic extracts, and aqueous decoctions of the selected fruits for phytochemical analysis and to assess antioxidant and antibacterial activities, along with acute toxicity. The study employed the 2,2-Diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) methods to examine antioxidant properties. The antibacterial activity was assessed through minimum inhibitory concentration (MIC), minimum biofilm concentration (BMC), and biofilm formation analysis. The results indicated that the methanolic extracts of P. chilensis and the aqueous decoction of T. tetraptera exhibited high total phenolic contents (135 and 143 mg GAE/g, respectively) and demonstrated the best antioxidant activity. Furthermore, the hydromethanolic extract of T. tetraptera showed the most substantial biofilm inhibition (70.15%) compared to the other extracts from both plants. Importantly, none of the extracts showed signs of toxicity at a dosage of 2000 mg/kg body weight. In conclusion, T. tetraptera and P. chilensis fruits contain compounds responsible for significant antioxidant activity and demonstrate efficacy against P. aeruginosa PAO1. These fruits could be potential candidates for developing phyto-drugs to combat antibacterial resistance in respiratory tract infections.