The First Edition of the book which was published in 2006 received overwhelming response from students and researchers. In the fifteen years since the first edition of this book was published in 2006 with 10 chapters, I have received numerous email messages and phone calls from several readers commenting on the book and requesting for more information on Alkaloids, Phenolic compounds, Anthocyanin compounds, Essential oils etc.

Plants are used as medicine since time immemorial. One of the area of Ethnobotany, Ethnopharmacology is considered as the scientific evaluation of traditional medicinal plants (Cotton, 1996). Cox (1994) has suggested that the ethno-directed sampling is most likely to succeed in identifying drugs used in the treatment of gastrointestinal, inflammatory and dermatological complaints. The Plant kingdom is a virtual goldmine of potential drug targets and other active molecules awaiting to be discovered. It has been estimated that only 10 - 15 per cent of the 7,50,000 existing species of higher plants have been surveyed for biologically active compounds.

Dietary supplements from plant sources are sometimes referred to as phytopharmaceuticals. They are produced from fresh, dried or otherwise preserved plants or parts of plants. The active ingredients are usually not completely isolated but rather are obtained along with other naturally occurring components of the plant. These other components are often believed to influence the efficacy of the active ingredient. Sometimes the active ingredients are concentrated, and undesirable substances such as chlorophyll, tannins, or resins, are removed.

Phytochemicals from various parts of a plant or tree such as the leaves, the flowers, the seeds, the barks, the roots and the shrubs can be isolated. Once one comes in from collecting plants in the field, it is good idea to freeze them immediately in a freezer at – 20°C or a commercial freezer held at – 80°C (Kaufman et al., 1999). According to Harborne (1984, 1998), fresh plant tissues should be used for phytochemical analysis and the material should be plunged into boiling alcohol within minutes of its collection. Alternatively, plants may be dried before extraction.

Extraction is a process whereby the desired constituents of a plant are removed using a solvent. The primary ways for extraction of organic molecules of interest to biologists and medical investigators involve breaking open the cells. Cell rupturing is carried out in a variety of ways. The method used depends on the type of tissue used. For plant cells grown in cell suspension culture or for plant callus tissue, a French press or a sonicator can be used to break open the cell.

The different qualitative chemical tests can be performed for establishing profile of given extract for its chemical composition. The following tests may be performed on extracts to detect various phytoconstituents present in them.

All separation procedures depend mainly on some physical characteristics of the compounds. It is relatively easy to separate compounds that have significantly different physical characteristics by simple techniques such as solvent extraction. If the various compounds are similar to each other in their molecular size, any slight difference in any one of their physical properties is exploited to achieve separation. 

For qualitative and quantitative analysis of phytochemicals, chromatography can be used. Gas chromatography is a powerful means of performing qualitative and quantitative measurements of complex mixtures of volatile substances, which are vaporizable without decomposition.Gas Chromatography-Mass Spectrometry (GCMS) system is a widely used instrument for qualitative and quantitative analysis of solid, liquid, and gaseous samples. Samples are converted into gaseous ions and then separated on the basis of their mass-tocharge ratio. 

After isolation and purification of the compound, it has to be identified. It is necessary to find out the class of the compound first and then to find out the specific compound within the class. The class of compound is usually determined from the colour tests, solubility, Rf properties and UV spectral characteristics of the compound. Further identification within the class depends on measuring physical properties and spectral measurements and then comparing these data with those in the literature.

Phytochemicals are the individual chemicals from which the plants are made. Phytochemical is simply a word that means plant chemicals. Plants have the ability to synthesize mixtures of structurally diverse bioactive compounds with multiple and mutually potential therapeutic effects. The plants have the capacity of manufacturing the secondary products. Phytochemicals with antioxidant properties tend to be brightly colored because they contain chromophores, ie, a series of alternating single-bonded and double-bonded carbons. Isoprene is often the building block of such units. The darkest green vegetables contain the most chlorophyll, and vegetables with the most chlorophyll require the most antioxidants.

The following plants have been worked out in the laboratory of Prof. N. Raaman: Cynodon dactylon, Artemisia pallens, Leptadenia reticulata, Clausena dentata, Tylophora indica, Aristolochia bracteolata, A. indica, Cissus quadrangularis, Hypericum mysorense. and Solanum trilobatum. Out of some of the data of these plants have been included in the previous chapters. In this chapter, compound isolation (CD1) from Clausena dentata (worked by Dr. R. Kamaraj) and characterization of the compound are given in detail.

Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. Alkaloids showed quite diverse medicinal properties (Rates, 2001). Many of them possess local anesthetic properties, but their practical use is limited for clinical purposes (Hesse, 2002). Morphine is one of the most known alkaloids isolated from Papaver somniferum (opium poppy), which had been used and still is for medical purposes. This alkaloid is a powerful narcotic which is used for the relief of pain, but its usefulness is limited because of its addictive properties.

Phenolic compounds constitute a major class of plant secondary metabolites that are widely distributed in the Plant Kingdom. Plant phenolics are biosynthesized through the shikimate/phenylpropanoid pathway leading to different compound classes. They may occur in their natural sources in free forms, as glycosylated or acylated derivatives, and as oligomeric and polymerized structures, such as hydrolyzable and condensed tannins, phlorotannins or lignins. They may also be found linked to plant matrix components such as cell walls, carbohydrates or proteins. It should be indicated that although the terms “plant phenolics” and “polyphenols” are indistinguishably used by some authors, they are not synonymous.

Anthocyanins are members of the flavonoid group of phytochemicals, a group predominant in teas, honey, wines, fruits, vegetables, nuts, olive oil, cocoa and cereals. The primary players in this group include the anthocyanins (eg, cyanidin, pelargonidin, petunidin), flavonols (quercetin, kaempferol), flavones (luteolin, apigenin), flavanones (myricetin, naringin, hesperetin, naringenin), flavan-3-ols (catechin, epicatechin, gallocatechin), and although sometimes classified separately, the isoflavones (genistein, daidzein) (Skibola and Smith, 2000).

Essential oil is a concentrated hydrophobic oily fragrance liquid extracted from plants, containing easily evapourated chemical compounds at room temperature. Essential oils are extracted from the different plant parts including the flowers, leaves, stem, bark, and roots, and they are extracted from different techniques. The most preferable method of extraction is hydro distillation which is easy to use and cheap. Essential oils are used in every field of life, used in aromatherapy, and act as antifungal, antioxidant, anxiety, pain relievers, and depression.

Abraham, R.J. and Loftus, P. 1978. Proton and Carbon-13 NMR Spectroscopy. Heyden, London, U.K. Agrawal, P.K. 1989. Carbon-13 NMR of Flavonoids. Elsevier, Amsterdam, The Netherlands. Andersen, Ø. M. and Jordheim, M. 2006. The Anthocyanins. In Flavonoids: Chemistry, Biochemistry and Applications, Ø. M. Andersen, K. R. Markham, (Eds.), CRC Press: Boca Raton, pp 471-553. Andersen, Ø.M., Fossen, T., Torskangerpol,l K., Fossen, A. and Hauge U. 2004. Anthocyanin from strawberry (Fragari) with the novel laglycone, 5 carboxypyranopelargonidin. Phytochemistry, 65: 405-410.

Acer rubrum 225 Achiote 253, 274 Achira 248