# _Pipper nigrum_ Fruit Extract as an Antibiotic Resistance Reversal Agent in MDR Bacteria
## 4 Discussion  
_P. nigrum_ is a plant of medicinal importance. The extracts of _P. nigrum_ in different solvents by fractionation contain many active components [18; 21; 22; 23] that can be used for antibiotic resistance reversal. Erythromycin belongs to the macrolides class of antibiotics, clindamycin belongs to the lincosamide group of antibiotics, amikacin belongs to aminoglycos, and gentamicin belongs to the aminoglycos class of antibiotics, which inhibit bacterial growth by inhibiting protein synthesis [30; 31]. In the present work, the use of _P. nigrum_ extracts supplemented with different antibiotics on _S. aureus_ growth revealed that the plant extracts increased the zone of inhibition to a significant level. According to the phytochemical analysis of _P. nigrum_, it contains flavonoids, glycosides, alkaloids, and tannins that have resistance reversal activity [9] and antioxidant activity [32]. Levofloxacin is a DNA synthesis inhibitor, and it belongs to the fluoroquinolones class, 2 nd generation [31]. Levofloxacin resistance is developing due to environmental factors [30]. However, this resistance can be reversed by using compounds from natural plant sources. Our results showed that, with the help of _P. nigrum_ extracts, MPN, and APN, in combination with levofloxacin, _S. aureus_ growth inhibition increased to a significant level, indicating the antibiotic reversal activity of this extract. However, ciprofloxacin belongs to fluoroquinolones, which inhibit DNA synthesis in bacterial cells and the growth of bacteria [31]. By using plant extracts, the zone of inhibition of _S. aureus_ was not increased as much, so these extracts did not reverse the resistance of ciprofloxacin in _S. aureus_[9; 30] because these extracts have a very low effect on the DNA synthesis process. cefoxitin belongs to the class of beta-lactam antibiotics. It kills bacteria by inhibiting the process of cell wall synthesis [31]. No significant increase in the cefoxitin zone of inhibition of _S. aureus_ was observed compared to other antibiotics. The effect of these extracts supplemented with different antibiotics was also evaluated for antibiotic resistance reversal with _Salmonella typhi_. Amikacin and gentamicin belong to the aminoglycos. Tigecycline is a broad-spectrum drug belonging to the antibiotic class glycylcycline, derived from the tetracycline class; it inhibits bacterial growth by inhibiting the protein synthesis mechanism in the bacterial cell [31]. Using _P. nigrum_ extracts in combination with these antibiotics, the zone of inhibition of _S. typhi_ significantly increased. _P. nigrum_ contains volatile compounds, monoterpenes and sesquiterpenenes, which have antibacterial, antioxidant, antifungal, anti-asthmatic, and anti-carcinogenic properties. These plant extracts help antibiotics in the killing of bacteria [33]. Tigecycline susceptibility decreases due to the development of resistance by ribosomal protection and an active efflux pump mechanism [31]. By using _P. nigrum_ extracts with tigecycline, the zone of inhibition was increased with EAPN, n-HPN, n-BPN, MPN, CPN, n-BPN, and APN. Therefore, the significant results obtained in the present study suggest  
Figure 15: Antibiotic reversal activity of _P. nigrum_ extracts in combination with cefotaxime (30 \(\upmu\)g) for _S. typhi_. that these plant extracts may affect the efflux pump mechanism in _S. typhi_. It has been suggested that these plant extracts block the efflux pump and facilitate the drug's ability to kill bacteria [34]. According to the phytochemical analysis of _P. nigrum_, it contains many components, which include flavonoids, glycosides, alkaloids, and tannins, that help in the reversal of antibiotic resistance [9] by blocking the efflux pump in the bacterial cell. Ciprofloxacinalen belongs to fluoroquinolones, which inhibit DNA synthesis in bacterial cells and the growth of bacteria [31]. The present study suggested that _P. nigrum_ extracts have a very low effect on the reversal of ciprofloxacin resistance in _S. typhi_.