ACTIVE COMPOUNDS ISOLATED FROM PLANTS USED IN TRADITIONAL MEDICINE AND HOMOEOPATHY

For years, hundreds of plants, due to their active ingredients, are used in homeopathic medicine (Bartomeu Costa-Amic and Aldape Barrera, 1998). The plants synthesize various compounds, among which are flavonoids and related compounds, sesquiterpene lactones, coumarins, lignans, terpenoids, steroidal compounds, carotenoids, limonoids, meliacins, simaroubalidans, cardiotonic glycosides, alkaloids, and terpenes. Some of them are specific to the treatment of particular diseases (Solis-Salas et al., 2019; Dominguez, 1979). However, the active compounds mostly used in traditional medicine belong to the phenylpropanoid, flavonoids and related compounds, terpenoids, and alkaloids. Table 8.2 includes some plants used as homeopathic medicines in the world. Additionally, Table 8.2 describes the properties of each plant and related active compounds.

On the other hand, each society has systems such as alternative, traditional, and allopathic medicine or professional health systems that are influenced by differences between cultures. At a global level, there is greater interest and demand for the use of traditional and allopathic health systems, so a professional collaboration between both health systems is desirable (van Rooyen et al., 2015).

Some countries lack the regulation of plant products (James et al., 2018), but in others, they have governmental institutions commissioned to regulate them. In this sense, from 1938, all homoeopathic medicines included in the Homeopathic Pharmacopoeia of the United States are regulated under the Food, Drug and Cosmetic Act. Additionally, since 1962, the Food and Drug Administration has requested that clinical trial data must be provided for all new drugs that support the safety and efficacy before the medicine can enter the market. In Canada, these products are regulated by the Food and Drug Act of Canada since before January 2004 (Johnson and Boon, 2007). Therefore, the pharmaceutical industry develops phytochemical and biological processes that guarantee reliability in the consumption of its products. These processes include separation and characterization extraction methods.

TECHNIQUES FOR THE EXTRACTION, ISOLATION, AND CHARACTERIZATION OF ACTIVE COMPOUNDS

Medicinal plants synthesize a wide variety of compounds with medicinal properties. Among the main groups of compounds are phenylpropanoids, flavonoids

Plant	Properties	Active Compounds	Reference
Aesculus hippocastanum	Antioxidant, anti inflammatory, venoconstrictor, immimomodulator, antitumor, antiviral, and antifungal	Escin (beta-escin) (triterpenic saponin)	(Vaskova et al., 2015; Michelini et al., 2018; Patlolla and Rao. 2015; Pittler and Ernst, 2012; Felixsson et al., 2010; Sirtori. 2001)
Allium сера	Antioxidant, antimicrobial, antimelanogenesis, antispasmodic, and antiproliferative	Phenolics. sulfur compounds, and essential oils	(Benkeblia, 2005; Benkeblia, 2004; Prakash et al., 2007; Nuutila et al., 2003; Marrelli et al., 2019)
Arnica montana	Anti-inflammatory, Antioxidant, and cytoprotective	Helenalin (sesquiterpene lactone), flavonoids. and phenolic acids	(Olioso et al., 2016; Craciunescu et al., 2012; Lyl3 et al., 1998)
Atropa belladonna	Sedative, local analgesic, hypertensive antiarrhythmic, antiulcer, and antiviral	Atropine (alkaloid), scopolamine (alkaloid), and hyoscyamine (alkaloid)	(Bousta et al., 2001; Kwakye et al., 2018)
Silybum mahanmn L. Gaertn	Antioxidant, antiliepatotoxic, antiinflammatory. antitumor, antibacterial.	Silymarin extract (polyphenolic flavonolignans): major components are silybin, taxifolin, and quercetin (flavonoids)	(Rakelly de Oliveira et al., 2015; Ebrahimpour koujan et al.. 2015; Wellington and Jarvis, 2001)
Chenopodium anthelminticum Linn	Cytotoxic against tumor cell lines	Ascaridol isolated from essential oils	(Yadav et al.. 2007; Efferth et al., 2002)
Cinnamomum zeylanicum	Antidiabetic, antioxidant, antimutagenic, antitumor, and antimicrobial	Essential oils, such as eugenol and cinnamaldehyde, and cynanmiic acetate	(Cardoso-Ugarte et al., 2016; Husain et al., 2018; Verspohl et al., 2005)
Colchicum autumnale	Antirheumatic and anti-inflammatory	Colchicine (alkaloid)	(Akraui, 2012; Kurek, 2018)
Echinacea angustifolia	Anti-inflanmiatory, inmiunostimulator, antioxidant and antimicrobial	Flavonoids. lipophilic compounds, such as alkamides and ketoalkenes, and hydrophilic phenolic compounds, such as caffeic acid derivatives	(Shaffique et al., 2018; Bonomo et al., 2017; Kindscher, 2016)

Plant	Properties	Active Compounds	Reference
Ha mom el is Virginian a	Astringent, anti-inflammatory, antioxidant, antiviral, and inhibits cancer cell proliferation	Tannins, such as proanthocyani- dins, hamamelitannin pentagalloyl- glucose, gallotannins, and gallates	(Sanchez-Tena et al., 2012; Tourino et al., 2008; Theisen et al., 2014)
Juglans regia	Cytotoxic against various human cancer cell lines: lung (NCI-H322 and A549), breast (T47D), skin (A-431), prostate colon (Colo- 205 and HCT-116), and prostate (PC-3 and DU-145)	Juglone	(Panth et al., 2016)
Lippia mexicana	Anti-infl ammat ory	Lippiolide and lippiolic acid	(Maldonado et al., 2010)
Lophophora williamsi	Acts as a neurotransmitter	Mescaline	(Hassan et al., 2017)
Matiicaiia chamomilla	Antimicrobial Fungistatic Antiseptic	a-bisabolol Umbelliferone Chamazulene and a-bisabolol	(Singh et al., 2011)
Persea americana	Anti-infl ammat ory Antiparasitic (against epimastigotes and trypomastigotes) Virustatic (inhibiting HIV syncytium formation and viral p24 antigen formation)	1.2.4- Trihyd roxyhepta dec -16 -ene 1.2.4- Trihidroxiheptadec- 16-eno Quercetin	(Yasir et al., 2010)
Piper nigrum	Anticancer and antimetastatic	Pipeline	(Paarakli et al., 2015)
Plantago major	Antibacterial, antiallergic, anti-inflammatory, antioxidant, and enzyme inhibitory activities	Plantamajoside	(Amakura et al., 2012)
Salvia officinalis	Antifungal	Carnosol and 12-methoxy-trans- carnosic acid	(Kerkoub et al.. 2018)
Tax.xus baccata	Anticancer	Taxol	(Kooti et al., 2017)
Ruta graveolens	Anti-infl ammat ory	Skimmianine	(Mancuso et al., 2015)

The list of plants was compiled from the Pharmacopoeia of the Mexican United States (Bartomeu Costa-Amic and Aldape Barrera, 1998).

and related compounds, terpenoids, and alkaloids. Phenylpropanoids represent a group of compounds synthesized by secondary plant metabolism through the shikimic acid pathway and include lignans and coumarins. Flavonoids, quinones, tetracyclines, and acetogenins are a group of compounds synthesized by the malonyl coenzyme-A pathway. Terpenoids (monoterpenes, diteipenes, sesquiterpenes, steroids, and limonoids) are synthesized through the mevalonic acid pathway and alkaloids by the three metabolic pathways (Solis-Salas et al, 2019; Dominguez, 1979; Tetali, 2019; Nabavi et al., 2018). According to its chemical structure, each group of compounds has characteristics of affinity for solvents or extraction, separation, and identification conditions (Dominguez, 1979). Therefore, some extraction, isolation, and characterization techniques of the main groups of bioactive compounds identified in medicinal plants are described below.