**3. Essential oils used against bacteria and microbes**

It is a fact that many of the bacterial infections have increased even after the discovery of many antibiotics, among other factors due to the appearance of strains resistant to antibiotics and the increase of the population with less immunity. This being one of the main causes of deaths due to infectious diseases caused by bacteria [18]. Additionally, the effects of toxicity due to side effects restrict the prolonged use of high concentrations of available antibacterial drugs. In this way it is evident the need to explore new molecules and alternative treatments against pathogenic bacteria, obtained from these natural products [19].

Many plant species contain molecules with antimicrobial properties. It has been shown that especially plant OEs exhibit broad-spectrum inhibitory activities against various bacterial pathogens [20]. In the case of the family of grasses, Poaceae, which includes the producer of lemongrass oil (of *Cymbopogon citratus*), citronella oil (of *C. nardus*) and palmarosa oils (*C. martinii*). The medicinally active components of these EOs are citral, geraniol and geranyl acetate. They have demonstrated antimicrobial and anticancer properties.

In the case of citrus oils that constitute limonene and linalool are derived from the fruit peel of the plants belonging to the Rutaceae family, it has been shown that these components exhibit antimicrobial potential. In the case of the plants *Pelargonium graveolens* and *Santalum* spp. of the family Geraniaceae and Santalaceae, respectively, it has been determined that they possess two important oils, namely, geranium oil and sandalwood, with similar properties [21].
