**2.** *Cissus sicyoides*

*Antioxidants*

Antioxidants are a set of substances that can delay or inhibit oxidation reactions and act as a defense mechanism to neutralize the harmful effects of oxidation in biological systems and foods [6, 9, 10]. Oxidative stress is considered a state of imbalance where excessive amounts of reactive oxygen and nitrogen species (ROS/RNS, for example, superoxide anion, hydrogen peroxide, hydroxyl radical, peroxynitrite) exceed the capacity of endogenous antioxidants (uric acid, superoxide dismutase, catalase, glutathione peroxidase), leading to the oxidation of a biomacromolecule variety such as enzymes, proteins, DNA, and lipids. Exogenous antioxidants (phenolic compounds, carotenoids, tocopherols, and ascorbates) are consumed in the diet mainly of fruits, leaves, seeds, vegetables, and cereals, they have the function of increasing or protecting the antioxidant defense in biological systems and, there-

It is conflicting that oxygen and nitrogen, considered essential for biological processes, are also cofactors for toxic and degenerative processes. In this sense, the antioxidant compounds act through different chemical mechanisms in order to minimize or maintain redox balance in vivo [9, 14]. There are several mechanisms by which oxidation can be inhibited. In general, the mechanisms involved include FRSs, ester bond enzymatic hydrolysis, transition metal ion sequestration, and enzyme-catalyzed peroxide reduction. The last three mechanisms mentioned do not cease reactive species action, but prevent the formation of molecules capable of

There is a growing interest in new sources of natural antioxidant compounds due to synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ ) in the food industry being severely restricted, since they may show carcinogenic effects on living organisms [16–18]. In this sense, the scientific community and consumers are looking for new bioactive compounds of natural origin that can be used to develop new treatments against diseases. In addition, they may be employed in the food industry as

*Cissus sicyoides* L., which belongs to the Vitaceae family, is also known as vegetal

*Rosmarinus officinalis* is an aromatic plant of the Lamiaceae family, native to the Mediterranean region. Today, it has been grown in many parts of the world and is known as rosemary [25, 26]. It has been recognized as one of the plants with great antioxidant activity. Among the most effective antioxidant constituents, cyclic diterpene diphenols, carnosic acid, rosmarinic acid, and carnosol have been identified. *R. officinalis* extracts have been used in the treatment and/or prevention of diseases such as cancer, Alzheimer's disease, urinary and gastrointestinal infections, diabetes, ischemia, and atherosclerosis [17, 25–32]. *R. officinalis* extract has been

Supercritical fluid extraction (SFE) has already been studied to obtain bioactive compounds from natural sources. Salazar et al. and Carvalho et al. showed that the application of SFE technology is successful in obtaining extracts from *C. sicyoides* and *R. officinalis*, respectively, with high antioxidant capacity [24, 33]. SFE is based on the use of solvents with temperatures and pressures above their critical points, which have a high solvency power. One of the most commonly used solvents in SFE is carbon dioxide (CO2) since its critical points are moderate, nontoxic,

insulin, anil-trepador, bejuco-caro, cipó-pucá, or puci. It is considered a plant from the Neotropical region and is usually found in the Amazon region [19, 20]. According to studies on *C. sicyoides* extract composition, the presence of bioactive compounds with high antioxidant activity as carotenoids and phenolic compounds (flavonoid, resveratrol, coumarins, and tannins) was found [21–23]. Therefore, it is a plant traditionally used by Brazilian popular medicine to treat rheumatism,

epilepsy, stroke, abscesses, arthritis, and diabetes [23, 24].

commercially exploited as a natural antioxidant [5, 16].

fore, they are important for endogenous oxidative stability [11–13].

promoting free radical chain reactions [15].

functional food ingredients.

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