**5.1 Antiulcer ptentiel**

Essential oils are widely used in the treatment/prevention of digestive pathologies. Terpenes and phenylpropanoids found in many essential oils have been shown to have potential for use in peptic ulcer disease [35]. The authors suggested that the anti-ulcer action is due to bioactive volatile molecules and their mechanisms of action, such as restoring the activity of antioxidant enzymes and the level of nonenzymatic antioxidants, recovering the level of mediators intracellular, and restorating pH. Essential oils also exerted an effect against *Helicobacter pylori* bacteria and improved the gastric mucosal barrier.

### **5.2 Antidiabetic capacity**

EOs have shown a series of biological properties with health-promoting conduct in humans. Among the chemical groups that make up essential oils, terpenoids are characterized by their hypoglycemic effect. These molecules inhibit enzymes responsible for the development of insulin resistance and normalization of plasma glucose and insulin levels [36]. These bioactive molecules exert an inhibitory effect in the process of carbohydrate metabolism and prevent the phenomenon of insulin resistance and finally of the serum glycaemia level [37]. In addition, it has been suggested that triterpenes have contributed to the treatment of diabetic neuropathy and nephropathy by inhibiting several pathways involved in the diabetes and associated complications [36]. On the other hand, the *Aegle marmelos* leaves' volatile molecules showed strong antidiabetic activity [38]. In another report, it was demonstared that the antidiabetic effetct of *Lavandula stoechas* essential oil is due, partly, to its potent antioxidant properties [39].

## **5.3 Anti-inflammatory properties**

The different compounds of essential oils are also characterized by powerful antiinflammatory effects. In this context, Baricevic et al. [40] proved that ursolic acid isolated from the *Salvia officinalis* EO was the main component of its anti-inflammatory power. On the other hand, certain terpenoids such as scropolioside like iridoids have shown potential for anti-inflammatory, hepatoprotective, and wound-healing activity [41, 42]. Terpenes and terpenoids are promising in the treatment intestinal inflammatory and have been also shown to display a broad range of biological activities in various human disease models [43]. Few other volatile terpenes and terpenoids, mainly monoterpenes, oxygenated terpenes, terpene esters, and sesquiterpenes, showed anti-inflammatory properties [44]. In addition, the anti-inflammatory effect of the *Ammodaucus leucotrichus* fruits' EOs has been demonstrated by the evaluation of the antiedematogenic response of essential oils in Carrageenan-induced hind paw edema in animal model [45].

### **5.4 Anticancer activity**

*In vitro*, certain terpenoids isolated from the roots of *Salvia officinalis* exerted a protective effect against cellular and DNA damage during human carcinomas. On the other hand, the α-humulene, a sesquiterpene compound identified in officinal sage essentail oils, demonstrated strong cytotoxic activity in human prostate carcinoma

cells. Trans-caryophyllene, isolated from *Salvia officinalis*, also exerted high cytotoxic activity against renal cell carcinoma cells [46, 47]. In addition, research work conducted by Li et al. [48] showed that natural bicyclic sesquiterpenes exhibited potential anticancer activity.

### **5.5 Hepato-nephroprotective effect**

Volatile compounds are known for their hepato-hepato-nephroprotective actions. In this regard, Fahmy et al. [49] evaluated, on animal model, the potential effect of essential oils extracted from sage plant against carbon tetrachloride (CCl4)-induced hepato/renal toxicities. This study confirmed that *Salvia officinalis* essential oils (SOEO) represent a potential candidate to reverse CCl4-associated hepato/renal damage. This effect may occur via an antioxidant defense mechanism that is partly related to the complexity of its chemical constituents.
