*Cytotoxicity Studies of Fruit-Extracted Metal Nanostructures DOI: http://dx.doi.org/10.5772/intechopen.106140*

#### **Figure 5.**

*Cytotoxicity studies of (a) & (b) A549 (lung cancer) cell lines of Punica granatum and Citrus reticulata and (c) & (d) HCT116 (colon cancer) cell lines of Punica granatum and Citrus reticulata of Ag NPs and Au NSs.*

comparison to controls. *Punica granatum*-produced Ag and Au NPs demonstrated considerable cytotoxicity against lung and colon cancer cell lines, as shown in **Figure 5a** and **c**. *Punica granatum* produced Au NPs against lung cell lines and Ag NPs against colon cell lines, which demonstrated decreased viability of 42–40%. *Punica granatum* extract revealed no substantial toxicity, indicating that the capping agent has a minor role in toxicity. *Punica granatum*-produced Ag and Au NPs have half-maximum inhibitory concentrations (IC50) of 115 g/ml and 114 g/ml; 107 g/ ml and 143 g/ml, respectively. **Figure 5b** and **d** reveals that Ag and Au NPs generated by *Citrus reticulata* are resistant to A549 and HCT116 cell lines. Cell viability decreased as the concentration of Ag and Au NPs rose. *Citrus reticulata* produced Au NPs against A549 and Ag NPs against HCT116 cell lines were found to have reduced viability, however *Citrus reticulata* extract was shown to have 100% viability. *Citrus reticulata* produced Ag and Au NPs have IC50 values of 106 g/ml and 121 g/ml; 110 g/ ml and 206 g/ml, respectively.

### **4.6 Antimicrobial studies**

**Figure 6** and **Table 1** indicate the inhibitory effect of Ag and Au NSs derived from *Punica granatum* and *Citrus reticulata* extracts. Silver nanoparticles from *Citrus* 

**Figure 6.**

*Antibacterial activities of Ag and Au NPs against (a) Acinetobacter baumannii and (b) Staphylococcus aureus with (1) 10 μl, (2) 20 μl and (3) 30 μl.*


#### **Table 1.**

*Inhibition zones of Ag and Au NSs.*

*reticulata* extract (O-Ag) outperform *Punica granatum* silver nanoparticles (P-Ag) in these tests. However, Au NSs produced from *Punica granatum* (P-Au) and *Citrus reticulata* extracts (O-Au) had no antibacterial activity. The bacterial activity of the nanoparticles is determined by the inhibitory zones. Compared to *S. aureus*, silver nanoparticles have higher activity against *A. baumannii* (Gram-negative) (Gramnegative). The zone of inhibitions of P-Ag with10, 20, and 30 μl against Gramnegative and Gram-positive bacteria are 1.3, 1.5, 1.8 cm, and 1, 1.5, 2 cm, respectively. Similarly, for O-Ag are 2, 2, 2.5 cm, and 1.8, 2.2, and 2.4 cm against Gram-negative and Gram-negative bacteria, respectively, at different doses. When it comes to

*Cytotoxicity Studies of Fruit-Extracted Metal Nanostructures DOI: http://dx.doi.org/10.5772/intechopen.106140*

bacterial activity, smaller particles having large surface area have greater bacterial activity than larger particles. According to the literature, cell penetration causes intracellular loss, which leads to cell death, and this inhibition is reliant on number of nanoparticles [47, 48]. The cell death is caused by silver. Due to their thin peptidoglycan coating, Ag NPs are usually more effective for Gram-negative bacteria than Gram-positive bacteria. However, in recent studies, Ag NPs have been shown to have higher antibacterial activity against Gram-positive bacteria, indicating that these Ag NPs have significantly higher antibacterial activity than other nanoparticles. Because of their small size, nanoparticles are prone to aggregation, which limits their use. In toxicity investigations, it is significant.
