**5. Sea Buckthorn (***Hippophae rhamnoides L.***)**

A native plant of Asia and Europe, sea buckthorn is a hardy winter shrub that flourishes throughout the year (**Figure 7**). This species is divided into eight subspecies, which are economically valuable [54]. These subspecies are abundant and commercially cultivated mainly in Asia, where sinensis and Mongolia are found. In addition to drought, salinity and alkalinity, sea buckthorn can also withstand extreme temperatures and salinity.

**Figure 7.** *Sea Buckthorn.*

#### **5.1 Phytochemistry**

The fatty acid content of sea-buckthorn fruit oil makes it unique compared to other vegetable oils. This oil contains rare palmitoleic acid (omega-7), a component of skin lipids that helps stimulate regenerative processes in skin cells and promotes wound healing. Sea-buckthorn oil also contains numerous active substances, resulting in multiple effects. There are exceptionally high vitamins A, C, E, F, P, and B complex in the oil [55]. Its regenerative and anti-wrinkle properties are attributed to vitamin A in carotenoids (200 mg/100 g). The vitamin C content of orange fruit (approximately 695 mg/100 g) is 15 times higher than in oranges. Vitamin C has antioxidative and protective properties against ultraviolet A and UVB rays. The walls of capillary blood vessels are strengthened by vitamin E, which is present in the form of tocopherols (approximately 200–600 mg/100 g) and minerals [56]. It also contains sterols, fruit acids (malic acid, citric acid), phenolic compounds, tannins, sugars, synthecanthins, phospholipids, ascorbic acid, selenium, copper, and zinc mineral salts.

#### **5.2 Medicinal and nutritional value**

Sea Buckthorn contains important phytochemicals like flavonoids, carotenoids, fatty acids etc. Studies have shown that sea buckthorn has high antioxidant activity. This plant can be used as a natural remedy for cardiovascular diseases and in diseases of skin, liver and stomach as well [56]. There are a lot of phytopharmaceuticals present, mainly phenolic compounds such as curcumin, resveratrol and proanthocyanidins which are known for cancer chemoprevention [57]. It is found that the seed oil of this plant enhances non-specific immunity and has anti-tumor effects. However, clinical studies with Sea Buckthorn need to validate the effects and mechanism on human cancer patients [15]. Sea Buckthorn helps in reducing cholesterol and improve cardiovascular health. It increases the blood circulation and relaxes cardiac muscle tissues which helps in restoring cardiac function [58]. To protect the cells of immune system and balance the inflammation, antioxidants are very important. There are a lot of antioxidants, isorhamnetin, quercetin, kaempferol in Sea Buckthorn. It has carotenoids, vitamin C and E as well which makes this fruit rich in anti-inflammatory properties as well [59]. Furthermore, it prevents gastrointestinal ulcers as it reduces inflammation. Researches have also shown that Sea Buckthorn helps in balancing liver enzymes and protects the liver from harmful effects of toxic chemicals [60]. The oil of this fruit contains palmitoleic acid which is a component of skin. It helps in the treatment of burns and healing of wounds. Sea Buckthorn oil has UV- blocking and emollient properties which help in regeneration of tissues [60].

### **6. Tea tree (***Melaleuca alternifolia***)**

Tea tree oil (TTO) is also known as Melaleuca alternifolia (**Figure 8**). The volatile essential oil derived from the Australian native plant offers a variety of medicinal properties. Many cutaneous infections are treated using TTO as its active ingredient due to its antimicrobial properties. There are over-the-counter versions of Melaleuca alternifolia available in Australia, Europe, and North America.

Herbal products and medicinal uses of this plant are very important [61]. To treat sore throats and skin ailments, tea tree leaves infusions were made from the leaves of the tea tree, which were also used for cough treatment. Traditional medicine of the Aboriginal Bundjalung people of eastern Australia relies on Melaleuca alternifolia leaves crushed and its oil to cure coughs, colds, and to treat wounds [62]. After its anti-microbial properties were reported in a series of papers in the

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

**Figure 8.** *Tea tree.*

1920s and 1930s, Melaleuca alternifolia oil became widely known for its benefits. It was Melaleuca alternifolia which was reported to be 11 times more potent than phenol in its antimicrobial properties that led to tea tree oil being used in industry for the first time. In the 1950s, the introduction of antibiotics prompted a decline in the use of natural products in medicine, which had a negative effect on the production of tea tree oil [63]. During the 1970s, there was a general renaissance of interests in natural products such as tea tree oil. A large-scale production of consistent essential oils was achieved through commercial plantations established in the 1970s and 1980s. Melaleuca alternifolia is typically used to extract tea tree oil commercially, but Melaleuca *dissitiflora* and Melaleuca *linariifolia* can also be used to extract tea tree oil [10]. Tea tree oil has been extensively studied for its antibacterial, antifungal and antiviral properties.
