P |
lants accumulate extractable organic substances, in quantities sufficient to be economically useful as active medicinal constituent for the ailment of various diseases. In addition to primary metabolites which occur generally in bulk volume concentrated in seeds and other vegetational storage organs, fulfill the needs for physiological development of plant itself due to their role in basic metabolism. Secondary metabolites are those compound which are not directly involved in the normal growth, development or reproduction of plant cell but are of greater importance because of their role in defense against predators and diseases( Luckner, 1972; Mann, 1978: William et al., 1989 Sharma et al., 2007). In plants, the malvonate and shikimate pathway are extensively involved in production of secondary metabolites and linked with primary metabolism bia Actyle-CoA and pentose phosphate pathway (Fig.6.1).Plants produce near about 50,000 types of secondary metabolites, in which 12000 types of alkaloids, 60 types of cynogenic glycosides, 15000 types of terpenes, 4000 types of flavonoids and 100 types of glucosinolates have already identified (Croteau et al., 2000 ).
Among the plant metabolites, alkaloids are specific molecules that have strong physiologic effects on living system. All the alkaloids are heterocyclic compounds containing one or more number of nitrogen (table 6.2).
Phytochemicals
S. No. |
||
Table 6.2: A variety of alkaloids present in plants
S.No |
|||
Table 6.3 : Important alkaloids of Acacia species (Clement et al., 1998)
S.No |
||
There are many methods that have been used for qualitative and quantitative analysis of plant metabolites. The qualitative analysis is generally used to identify a particular photochemical in plants, using a particular method for instance: Shinoda's test for Flavonoids, Mayer's, Dragendorfrs, Hager's and Wagner's reagents for alkaloids, Fehling's solutions for carbohydrates. The quantitative analysis is used to estimate or isolate the total amount of phytochemicals from the dry powder or ashes of subjected plant part (Liu et al., 1993).
Phytochemical studies have been carried out on several plants viz. Beyeria leschenaulth (Baddeley et al., 1964), Artemisia douglasiana (Matsueda and Geissman, 1967), Calendula officinalis (Kasprzyk and Pyrek, 1968), Cactus ( Jolad and Steelink, 1969), Artemisia nova (Irwin and Geissman, 1969), Artemisia ludoviciana (Geissman and Saitoh, 1972), Gymnosporia wallichiana (Kulshreshtha, 1977), Catha cassinoides (Betancor et al., 1980), Acacia dealbata (Imperato, 1982), Tanacetum vulgare (Ognyanov and Todorova, 1983), Salvia pratensis (Anaya et al., 1989), Ajania achilleoides (Zdero et al., 1990),Salacia cordata (Tinto et al., 1992),Phyllanthus flexuosus (Tanaka et al.,1993), Anthems carpatica (Bulatovic et al.,1997), Maria oblongifolia (Abdel-Mogib,1999), Anthemis carpatica (Vajs et al., 2000), Ficus microcarpa (Chiang and Kuo, 2001), Pavetta crassipes (Sanon et al., 2003), Acanthospermum hispidium (Sanon et al., 2003), Acacia mellifera (Mutai et al., 2004), Dtanthus maritimus (Christodoulopoulou et al., 2005), Acanthopanax koreanum (Park et al., 2005),Tragia involucrata( Samy et al., 2006), Boswellia serrata (Sharma et al., 2007).
