Introductory Chapter: Plant Extracts

*Aman Dekebo*

### **1. Introduction**

Humans are dependent on plants for basic needs such as food, clothing, and shelter for centuries [1]. Plants have also been used as arrow and dart poisons for hunting, poisons for murder, hallucinogens used for ritualistic purposes, stimulants for endurance, and hunger suppression, as well as inebriants and medicines [1]. Medicinal plants have been a source of wide variety of biologically active compounds for many centuries and used extensively as crude material or as pure compounds for treating various disease conditions. Relatively 1–10% of plants are used by humans out of estimated 250,000–500,000 species of plants on Earth [2]. Plant-based traditional medicine plays a key role in the development and advancement of modern studies by serving as a starting point for the development of novelties in drug discovery [3]. Various modern drugs were extracted from traditional medicinal plants through the use of plant material following the ethno botanical leads from indigenous cures used by traditional medical systems [4]. In developing countries and rural societies, the use of medicinal plants is both a valuable resource and necessity, and furthermore, it provides a real alternative for primary healthcare systems [5].

Plants were once the primary source of medicines in the world and since then, plants continue to provide humans with new remedies as 50% of all drugs in clinical use in the world are derived from natural products, of which higher plants contribute 25% of the total [5, 6]. The use of plants as medicines predates written human history. Knowledge of plant use was widespread in ancient civilizations. Until the middle of the nineteenth century, plants were the main therapeutic agents used by humans, and even today, their role in medicine is still relevant. It was estimated by the WHO that around 80% of the world population relied on medicinal plants as their primary healthcare source [7] and the demand is increasing in developing countries. For example, traditional medicine (TM) practices have been used for thousands of years by people in Africa, China, India and many other countries [8]. Even in developed countries, plant-based traditional medicines are often termed complementary or alternative medicine (CAM), and their use has increased steadily. For example, in the USA alone, the total estimated that herbal sales for 2005 were \$4.4 billion, a significant increase from \$2.5 billion in 1995 [9].

The plant chemicals used for arrow or dart poisoning purposes are largely the secondary metabolites, which are derived biosynthetically from plant primary metabolites (e.g., carbohydrates, amino acids, and lipids) and are not directly involved in the growth, development, or reproduction of plants. Secondary metabolites can be classified into several groups according to their chemical classes, such as alkaloids, terpenoids, tannins, phenolics, and others [10]. Most of these secondary metabolites are used for plants defense against predators.

Medicinal plants are now more focused than ever because they have the capability of producing many benefits to society especially for medicinal uses. The medicinal power of these plants is due to their phytochemicals which can cause definite physiological actions on the human body. Phytochemicals are natural compounds which occur in plants such as medicinal plants, vegetables, and fruits that work with nutrients and fibers to act against diseases or more specifically to protect against diseases [11, 12]. Medicinal plants because of their accessibility and affordable health care are an important source of livelihoods for indigenous and rural populations. They are also the source of many active ingredients for modern pharmaceuticals. Between 50,000 and 80,000 flowering plants are used for medicine worldwide, many of them are collected from wild resources [12]. Herb as a group of plants was also used as food (vegetables) and flavors for hundreds of years in many parts of the world. Herbs have been traditionally regarded as natural remedies for common ailments of a human. Nearly all cultures and civilizations from ancient times to the present day have used herbal medicines which are antimicrobial sources to cure infections [13]. Conventional antifungal and antibacterial treatment of infections becomes inefficient to cure patients, providing resistance of microorganisms.


#### **Table 1.**

*Compounds and extracts derived from plants used as drugs or on the process of clinical trial stage.*

**3**

*Introductory Chapter: Plant Extracts*

tea, and cocoa, respectively [8].

**3. Extraction methods**

cosmeceutical industry [39].

*DOI: http://dx.doi.org/10.5772/intechopen.85493*

**1.1 Plant-derived drugs and various clinical trial stages**

stage derived from plants and their therapeutic use.

**2. Uses of plant extracts in food industry**

**Table 1** shows compounds or extracts are drugs or on the process of clinical trial

Plants have also been used in the production of stimulant beverages, such as tea, coffee, cocoa, and cola, and intoxicants, such as wine, beer, and kava, in many cultures since ancient times. Tea (*Camellia sinensis* Kuntze) was first consumed in ancient China [1], while coffee (*Coffea arabica* L.) was initially found in Ethiopia from the region called Keffa and then cultivated in Yemen for commercial purposes in the ninth century [32]. The Aztec nobility is used to consume bitter beverages containing raw cocoa beans (*Theobroma cacao* L.), red peppers, and various herbs [32]. The active components of these stimulants are methylated xanthine derivatives, called caffeine, theophylline, and theobromine, major components of coffee,

Studies have shown that a low to moderate consumption of red wine is important for reduction of mortality caused by cardiovascular disease and cancer [33]. This health benefit of wine has been suggested to be due to the presence of a

Kava, a beverage made from the root of *Piper methysticum* Roxb., has been a popular intoxicating beverage in Polynesia for centuries [35]. However, in the Western world, kava is not normally consumed directly but has gained popularity as a botanical dietary supplement to ease the symptoms of stress, anxiety, and depression [36]. A study has shown that the anxiolytic activity of kava extract may

Medicinal plants are becoming very important due to their uses mainly as a source of therapeutic compounds that may lead to the development of novel drugs. Most of these compounds such as phenolics and flavonoids have been reported to be important for on health including cancer prevention [38]. High content of phenolic and flavonoids in medicinal plants has been correlated with their antioxidant activities that are important in prevention of the development of age-related disease, especially those related to oxidative stress [39]. Phytochemicals in medicinal plants are very important in pharmaceuticals and

Extraction is the separation of medicinally mixture of many plant metabolites, such as alkaloids, glycosides, phenolics, terpenoids, and flavonoids using selective solvents through standard procedures [40]. The aim of all solvent extraction methods is to separate the soluble plant metabolites, leaving behind the insoluble cellular

Maceration extraction method is used in wine making and also used for extraction of bioactive compounds from plants [39]. Maceration involved soaking plant materials (coarse or powdered) in a stoppered container with a solvent and allowed to stand at room temperature for at least 3 days with frequent agitation [40], which

compound called resveratrol present in the skin of grapes [34].

be mediated in part by the kavalactone and dihydrokavain [37].

marc. The following are the widely used extraction techniques.

**3.1 Maceration, infusion, percolation, and decoction**

*Plant Extracts*

resistance of microorganisms.

Combretastatin A4 phosphate

*Harpagophytum procumbens* extract

Mistletoe extract (Iscador)

Flavocoxid (Limbrel) blend of flavonoids

Galantamine *Galanthus woronowii*

Losinsk

Medicinal plants are now more focused than ever because they have the capability of producing many benefits to society especially for medicinal uses. The medicinal power of these plants is due to their phytochemicals which can cause definite physiological actions on the human body. Phytochemicals are natural compounds which occur in plants such as medicinal plants, vegetables, and fruits that work with nutrients and fibers to act against diseases or more specifically to protect against diseases [11, 12]. Medicinal plants because of their accessibility and affordable health care are an important source of livelihoods for indigenous and rural populations. They are also the source of many active ingredients for modern pharmaceuticals. Between 50,000 and 80,000 flowering plants are used for medicine worldwide, many of them are collected from wild resources [12]. Herb as a group of plants was also used as food (vegetables) and flavors for hundreds of years in many parts of the world. Herbs have been traditionally regarded as natural remedies for common ailments of a human. Nearly all cultures and civilizations from ancient times to the present day have used herbal medicines which are antimicrobial sources to cure infections [13]. Conventional antifungal and antibacterial treatment of infections becomes inefficient to cure patients, providing

**Drug Plant source Disease to treat Reference**

Apomorphine — Parkinson's disease [16] Tiotropium bromide — Obstructive pulmonary disease [17] Varenicline — Smoking cessation [18–20]

Ingenol 3-angelate *Euphorbia peplus* L. Warts and actinic keratoses [25] Morphine *Papaver somniferum* Pain [26] Protopanaxadiol *Panax ginseng* Apoptotic effect on cancer cells [27]

Ginkgo extract *Ginkgo biloba* L. Alzheimer's disease [29]

Sativex extract *Cannabis sativa* L. Neuropathic pain [31]

*Compounds and extracts derived from plants used as drugs or on the process of clinical trial stage.*

Betulinic acid Many plants Anticancer, antibacterial,

*Combretum caffrum*

ex Murray) Trevis

*procumbens* DC

*Harpagophytum procumbens*

Willd

*Scutellaria baicalensis* Georgi and *Acacia catechu*

Kuntze

Huperzine A *Huperzia serrata* (Thunb.

Harpagoside *Harpagophytum* 

Alzheimer's disease [14, 15]

[21, 22]

antimalarial, anti-HIV, anthelminthic, anti-

properties

*Viscum album* L. Various cancer [30]

inflammatory, and antioxidant

Anaplastic thyroid cancer [23]

Alzheimer's disease [24]

Pain [28]

Hip and knee osteoarthritis [28]

Osteoarthritis [1]

**2**

**Table 1.**

## **1.1 Plant-derived drugs and various clinical trial stages**

**Table 1** shows compounds or extracts are drugs or on the process of clinical trial stage derived from plants and their therapeutic use.
