**2. Aloe vera (***Aloe barbadensis miller)*

Aloe vera is a perennial succulent plant native to the plant family Asphodelaceae (**Figure 1**). Ayurveda, Siddha, Unani, and homeopathy are just a few indigenous systems of medicine that use homeopathic remedies. Among the 250 species of Aloe, Aloe vera is one of the 250 species of Aloe barbadensis miller [17]. Aloes grow in various climates, including deserts, grassland, coastal, and even alpine areas. They are often thought to only increase in hot, dry climates.

**Figure 1.** *Aloe Vera.* *Vegetable and Herbal Extracts: A Way towards Preventive and Therapeutics Regimen DOI: http://dx.doi.org/10.5772/intechopen.101104*

#### **2.1 Phytochemistry**

There are 75 active compounds in aloe vera which falls under vitamins, enzymes, minerals, sugars, lignin, saponins, salicylic acids, and amino acids. It contains antioxidant vitamins A, E and C*.* Furthermore, it contains folic acid, vitamin B12, and choline (**Figure 2a** and **b**).

The system includes eight enzymes: alkaline phosphatase, brady kinase, catalase, carboxypeptidase, cellulase, amylase, lipase, and peroxidase [18]. Excessive inflammation is reduced by topically applied brady kinase, whereas the others aid in breakdown of sugars and fats.

It has high concentrations of various minerals as calcium, chromium, copper, selenium, magnesium, manganese, potassium, sodium, and zinc [19, 20]. The plant provides polysaccharides glucomannan and polymannose as well as monosaccharides glucose and fructose. Mucopolysaccharides originate in the plant's mucilage layer. Monosaccharides that dominate are mannose-6-phosphate and glucomannans [beta (1,4)-acetylated mannan] [20]. Aloe vera gel has been shown to contain anti-inflammatory glycoprotein and a novel anti-allergic substance, C-glucosyl chromone [19]. It comprises 12 anthraquinones, which are phenolic compounds traditionally used as laxatives. Aloin and other hydroxy anthracene derivatives such as emodin are responsible for the laxative effect of Aloe vera. It also contains four fatty acids, cholesterol, campesterol, sitosterol and lupeol. Lupeol is also antiseptic, and analgesic and all of these compounds have anti-inflammatory properties [20].

#### **2.2 Medicinal and nutritional value**

Aloe vera has long been used to treat burns, commonly known as the burn tree and first aid plant. Aloe vera is anti-inflammatory, antibacterial, antiviral, increases immune activity, and has a lower histamine activity than other organic compounds, which accelerates burn wounds' healing. The medicinal properties of Aloe vera

**Figure 2.** *Structure of potent vitamins. Vitamin A (a). Vitamin E (b).*

have led to its increased popularity. It contains amino acids essential to wound healing [21]. Additionally, it contains several inorganic electrolytes, such as iron, potassium, magnesium, chromium, copper, sodium, calcium, and zinc, essential for wound healing [22]. By releasing growth factors, it produces antibodies and promotes wound healing. Aloe vera gel, has anti-inflammatory properties, healing effects, stimulation of mucus, and regulates gastric secretions, which can help prevent and treat gastric ulcers [22]. As a result of the presence of anthraquinones and chromone, aloe vera gel has strong anti-inflammatory properties [23]. Aloe vera also relieves joint pain because it has an anti-inflammatory effect. Inflammation is caused by the body's response to various injuries, which produces bradykinin (a mediator of inflammation). Aloe vera extracts stored for three to 10 days in the dark produce active compounds prostanoids from the glycoprotein and polysaccharide fractions. Chronic bronchial asthma can be effectively treated with these compounds. Several types of cancer are non-resistant to the chemo-preventive power of aloe vera due to its glycoproteins and polysaccharides [24]. These agents stimulate the immune system to fight cancer [22]. Researchers examined the cytotoxicity of barbarol, aloe-emodein, and aloesin extracted from Aloe vera against acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) [21].
