## 4 Natural Antioxidants and Their Role in Cosmetics
### Selected Plant Species with Antioxidant Activity
#### 4.11.9 Coffee arabica  
_Coffea arabica_, also known as the Arabica coffee, a species of the Rubiaceae family [233]. Coffee leaves contain a diverse range of phytochemicals, including alkaloids, polyphenols, diterpenes, and various other compounds. Among alkaloids, they are rich in purine derivatives such as caffeine, theophylline, and theobromine, as well as the pyridine alkaloid trigonelline, with caffeine and trigonelline being the most prominent. Polyphenols, particularly phenolic acids, flavonoids, xanthones, and tannins, are another key class of compounds in _Coffea arabica_. The primary phenolic derivatives in coffee leaves are chlorogenic acids (CGAs), with 5-caffeoylquinic acid being the most abundant. Other notable phenolic acids include ferulic, p-coumaric, protocatechuic, and sinapic acids. The leaves also contain important flavonoids like quercetin, rutin, and kaempfer. Diterpenes such as cafestol and kahweel, typically found in the lipid fraction of coffee seeds, are also present in coffee leaves. Carbohydrates identified include monosaccharides like glucose, fructose, galactose, and rhamnose, along with oligosaccharides such as sucrose and maltose. Additionally, polyols like treitol, sorbitol, and galactinol, as well as starch, contribute to energy storage in the plant. Green coffee beans are composed mainly of macronutrients and bioactive compounds, with carbohydrates making up 59-61%, lipids 11-17%, proteins 10-16%, phenolic compounds 6-10%, and minerals around 4%. Other constituents include fatty acids (2%), caffeine (1-2%), trigonelline (1%), and trace amounts of free amino acids. Roasting significantly alters the composition of green coffee beans, reducing carbohydrate content to 38-42%, while protein and phenolic levels drop to 8-14% and 3-4%, respectively [234].  
Chlorogenic acid (CGA), pyrocatechol (PC), and 3,4,5-tricaffeoyl quinic acid (TCQ), extracted from _Coffea arabica_ beans, were tested for anti-wrinkle effects in UVB-stimulated mouse fibroblast cells (CCRFs). CGA was the most effective, reducing MMP-1, MMP-3, and MMP-9 expression, increasing type-I procollagen production, and inhibiting ROS generation. It also showed good SPF, DNA protection, and xanthine oxidase inhibition. These results suggest CGA may help prevent UV-induced premature skin aging [233].  
The anticellularite properties of _Coffea arabica_ have gained interest in dermato-cosmetics due to its rich bioactive profile. Extracts, particularly those high in caffeine, chlorogenic acids (CGAs), and flavonoids, have shown effectiveness in addressing cellulite-related concerns. CGAs, especially 5-caffeoylquinic acid (5-CQA), play a key role by enhancing antioxidant defenses, reducing oxidative stress, and inhibiting enzymes that break down collagen and elastin--essential for skin firmness and elasticity. Flavonoids from _C. arabica_ further support anticellularite effects with their antioxidant and anti-inflammatory properties. Studies suggest that C. _arabica_-based formulations improve skin hydration and elasticity by stimulating microcirculation, increasing nutrient and oxygen delivery, reducing inflammation and edema, and promoting an even skin texture. Additionally, CGAs contribute to anti-aging benefits by neutralizing free radicals, minimizing oxidative stress, and protecting skin cells from premature aging [235].