## 4 Essential Oils as Active Secondary Compounds in Wound Dressings
impregnated eucalyptus oil nanoemulsion in chitosan film by casting method and performed the antibacterial test on formulated film. The in vitro bioassay on formulated films content 3% eucalyptus oil had activity against _Staphylococcus aureus_[159]. _Lawsonia inernis_ Linn is extracted from the henna tree and can be used in the healing of chronic and burn wounds due to its antioxidant, analgesic, anti-inflammatory, antibacterial, and antifungal activities. [PERSON] et al. prepared chitosan/polyethylene oxide (PEO) (90/10) nanofiber with _Lawsonia inernis_ (2 wt%) by electrospinning [160]. The enriched nanofiber showed antimicrobial activity against _Escherichia coli_ and _Staphylococcus aureus_. The in vivo test was performed on the back of rats for 14 days (Figure 4). The results showed that _Lawsonia internis_ could promote the wound-healing process [160]. Lavender EO (LEO) is extracted from the flowers of _Lavandula angustifolia_ and is known as an anxiety reducer, pain reliever, antioxidant, and anticancer agent [161; 162]. [PERSON] et al. formulated lavender EO in Alginate (SA)/PEO nanofiber to evaluate LEO antibacterial and anti-inflammatory activity and its influence in recovering burn wounds [163]. The antibacterial results showed nanofiber inhibition against _Staphylococcus aureus_. The anti-inflammatory activity was determined by in vivo test on the rat skin exposed to midrange ultraviolet radiation (UVB). The data suggested that the designed dressings affected the bacteria vitality. They were able to reduce the production of proinflammatory cytokines in human fibroblast cells by polymerase chain reaction (PCR) analysis and in mice exposed to UVB irradiation, evaluated by enzyme-linked immunosorbent assay (ELISA). This result proved that in the role of LEO in burn wound treatment by backing the cytokine levels to control value after 96 h without the appearance of erythema on their injured skin [163]. Lavender essential oil (LEO) is extracted from the flowers of _Lavandula angustifolia_ and is known as an anti-anxiety, analgesic, antioxidant, and anticancer agent [161; 162]. Figure 4: In vivo test on the back of the rats. (**a**) Blank chitosan/PEO nanofiber, (**b**) chitosan/PEO nanofiber containing 2 wt% _L. inernis_[160]. [PERSON] et al. formulated LEO in alginate/PEO nanofibers to investigate the antibacterial and anti-inflammatory activity of LEO and its effect on the healing of burn wounds [163]. The antibacterial results showed inhibition of nanofibers against _Staphylococcus aureus_. The anti-inflammatory activity was determined by an in vivo assay on rat skin exposed to medium ultraviolet radiation (UVB). The data suggested that the designed dressings affected the vitality of bacteria [163]. Clove oil extracted from _Syzygium aromaticum_ exhibits antioxidant and anticancer activity due to its secondary metabolite eugenol. [PERSON] et al. first analyzed the effect of clove oil in a wound excision rat model by oral administration. A clove oil nanoemulsion was obtained by spontaneous emulsification using triacetin as oil phase, Tween-80 as surfactant, Labrasol as cosurfactant, and distilled water as aqueous phase. It was found that the leucine content was higher compared to the treatment with pure clove oil and the control. Moreover, the absence of inflammatory cells in nanoemulsion-treated rats in the histopathological experiments showed that the clove oil nanoemulsion was safe and nontoxic [164].