Review of Literature

I. Wild Edible Plants

Ethnobotany is concerned with the relationships between man and

vegetation involving man's dependence upon vegetation as well as the tremendous

influence man has had on vegetation (King, 1974). Maheswari (1983) defined

ethnobotany as a study of the interaction of the primitive or the aboriginal human

society with their vegetation. Ethnobotany deals with the studies among the tribals

and rural people for documenting their unique knowledge about plant wealth and for

research of new resources of herbal drugs, edible plants and other aspects of plants

(Jain and Mudgal, 1999).

Wild species are increasingly endangered by the loss of habitats and by

the rapid agricultural developments. They should be conserved because these wild

related species of the cultivated crops are recognized by the plant scientists as future

resources of food which meet the need of increasing population (Singh and Hardas,

1969). Harlan (1969, 1984); Heiser (1976) and Hawkes (1990) have advocated the

conservation of wild relatives of cultivated plants to establish comprehensive gene

pool. The immediate objectives of crop evolutionary studies are collection and

evaluation of wild counterparts of the cultivated plants (Smart, 1978, 1980; Cohen et

al., 1991). Wild plants have, since ancient times, played a very important role in

human life. They have been used for food and medicine. To meet the demands of

increasing populations, it is important to find out the ways and means to increase the

production of the staple crops, and it is also important to investigate other possible

substitute sources of food from wild plants (Manandhar, 1995).

Jam (1964) enumerated the wild plant foods consumed by the tribals of

Baster in Madhya Pradesh. Pal and Banerjee (1971) enumerated less known plant

foods consumed by the tribals of Andhra Pradesh and Orissa. Saxena and Dutta

(1975) documented 12 wild edible plants consumed by the tribals of Orissa.

Aboriginal tribes of Ratan Mahal and surrounding hills of Gujarart are known to

consume some wild edible plants (Bedi, 1978). Janaki Ammal (1978) studied the food

plants consumed by certain tribals of South India for subsistence. Different ethnic

groups of North-Eastern region of India are known to consume the tubers, rhizomes,

leaves, tender shoots, buds, inflorescence, ripe fruits and edible seeds of 300 wild

edible plant species (Singh and Arora, 1978; Arora, 1990). Jain and Dam (1979)

documented some wild edible food plants of North-Eastern India.

The Mikiris in Karbi-Anglong district of North-Eastern India depend on the

natural plant resources of their neighbouring forests (Jain and Borthakur, 1980). The

Khasis and Garos of Meghalaya are known to consume 12 wild edible plants (Rao

and Neogi, 1980). Thothathri (1980) categorized the wild edible plants consumed by

the tribals in Andaman and Nicobar Islands.

In India, as many as 28 wild legumes are known to be utilized as pulses

by different tribal sects (Jain.1981). Ramachandran and Nair (1981) enumerated 35

wild edible plants consumed by the tribes namely Adiyars, Chingathans, Kadars,

Karimpalans Kattunayakans, Kudiyas, Kurichyas, Malayars, Mullas, Kurumbars,

Paniyas and Uralikurumbars in Cannanore district of Kerala. Ramachandran and Nair

(1981) enumerated 57 wild edible plants consumed by the Irulars in Coimbatore

district of Tamil Nadu. Singh and Singh (1981) enumerated 97 wild plants belonging

to 75 genera and 49 families consumed by the tribals of Eastern part of Rajasthan. The

7

Onges of the Andaman and Nicobar Islands are known to consume 21 wild edible

plants (Bhargava, 1983). Das et al. (1983) enumerated 84 species of angiosperms

predominantly used by the tribes in Totopara and its adjoining areas of Jalpaiguri

district, West Bengal.

The Nayadis of Northern Kerala, are known to consume about 15 wild edible

plants (Prasad and Abraham, 1984). Pal (1984) \enumerated the wild edible plants

used by the tribals of Subansiri, Arunachal Pradesh. Maihotra et al. (1985)

enumerated the wild edible plants of the local people in Garhwal district of Uttar

Pradesh. Singh and Singh (1985) enumerated 30 wild plants used as vegetables by the

indigenous people of Manipur. Kaul et al. (1985, 1990) documented the wild food

plants consumed by the tribals in North-West and Trans—Himalayan region.

The tribes namely Koknas, Mahadevs Kolis, Bhils, Warlis, Thakurs and

Katkaris in Nasik district of Maharashtra are known to consume 33 wild food plants

(Sharma and Laksahminarasinihan, 1986). Krishna and Singh (1987) enumerated the

wild edible plants consumed by the tribals of Sikkim. The War Jaintas in Jaintia hills

district of Meghalaya are known to consume 24 wild edible plants (Kumar et al.,

1987). The tribes in Subansiri district of Arunachal Pradesh are known to use 31 wild

edible plants as a source of food (Thothathri and Pal, 1987). Vartak and Kulkarni

(1987) documented a number of monsoon leafy annuals used as food by the local

tribal communities in the hilly areas of the Western Ghats of Maharashtra.

Chakrabarty and Rao (1988) enumerated 27 wild edible plants consumed

by the tribe Shompens in the Great Nicobar Island. The tribes namely Jaunsaries,

Kinnauris, Bhotiyas Marchas, Toichyas, Boks has, Gujars and Goddis of Uttar

8

Pradesh are known to consume 50 wild little known edible plant species belonging to

40 genera and 30 families (Negi, 1988).The Tangkhul Nagas in Ukhrul district of

Manipur are known to use certain wild edible plants as their food (Elangbam et al.,

1989). The tribals and other local inhabitants of Mt.Abu, Sirohi district and different

parts of Udaipur and Banswara districts in Rajasthan are known to use a number of

wild edible plants. (Sebastian and Bhandari, 1990). The Aos and Angamis of

Nagaland are known to use 56 wild edible plants as their food (Rao and Jamir, 1990).

Aminuddin and Girach (1991) documented the wild edible plants

consumed by the Bondos in Koraput district of Orissa. Bhattacharyya (1991)

documented the usuage of wild plants as a part of food by the people living in the

remote areas of Ladakh region of Northern Jammu and Kashmir. Ragupathy and

Mahadevan (1991) documented 53 wild edible plants consumed by the Irulas in the

coastal areas of Thanjavur district of Tamil Nadu. Girach and Aminuddin (1992a,

1992b) enumerated 115 little known edible plant consumed by the tribals and rural

societies of Orissa. Kulkami and Kumbhojkar (1992) documented some wild edible

fruits consumed by the Mahadevs Kolis in Western Maharashtra. The Bhuniyas and

Juangs in Keonjhar district of Orissa are known to use 31 wild edible plants (Mondal

and Mukherjee, 1992).

Rajendran and Henry (1994) enumerated the wild food plants consumed

by the Kadars in Anamalai Hills of Coimbatore district, Tamil Nadu. Radhakrihnan et

al. (1996) documented 31 wild edible plants consumed by the tribals inhabiting the

Kerala region of the Western Ghats. Das (1997) enumerated 153 wild edible plants

consumed by the backward aboriginals in Karauli and Sawai Madhopur districts of

Rajasthan. Manandhar (1997) documented 31 wild food plants consumed by tribal

communities in different parts of Nepal.

Awasthi and God (1999) documented 26 wild edible plants consumed

by the Onges and Negritos in the little Andaman Islands. Bhattacharyya (1999)

documented 15 wild edible plant consumed by the people of Druk-Yul (Bhutan). The

tribals inhabiting Aravalli Hills in South East Rajasthan are known to use the roots,

rhizomes, tubers, shoots, leaves, flowers, fruits, seeds, nuts, etc., as a source of food

not only in the times of food scarcity but also on a daily basis (Ketewa et al., 1999).

Kothari and Rao (1999) documented 30 wild edible plants used as food by the War/is

in Thane district of Maharashtra. The tribes namely Kondareddis, Valmikis, Koyas,

Konda Kapus and Kondakammars in East Godavari of district, Andhra Pradesh are

known to use the tubers, young shoots, leaves, ripe or unripe fruits and seeds of some

wild edible plants as a source of food (Prasad et al., 1999). Sharma et al. (1999)

documented 66 wild edible fruits consumed by the Melteis in Manipur. The Tharus in

sub-Himalayan region of Eastern Uttar Pradesh are known to use 25 wild edible

plants (Singh, 1999). Singh et al. (1999) documented 37 wild edible plants consumed

by the Tripuris in Tripura. The tribes namely Yanadis , Nakkalas, Irulas, Yerukalas,

Sugalis and Chenchus in Chitoor district of Andhra Pradesh are known to use 67

wild plant species as a source of food (Sudhakar and Vedavathy, 1999).

Joshi and Tewari (2000) enumerated 188 wild edible plants used as a source of

food by the tribals in Uttar Pradesh Himalaya. Maikhuri et al. (2000) enumerated the

wild edible plants used by 3 tribal sub communities of the Central Himalayas. Naqshi

and Aman (2001) enumerated 156 wild food plants consumed by the Gujjars and

Shephards in Kashmir Himalaya. Tabuti et al. (2004) documented about 31 wild food

10

plants consumed by the local community of Bulomogi, Uganda. Viswanathan (2004)

documented ethnobotanically important edible plants of Tamil Nadu belonging to 416

species, 149 genera and 74 families.

Santayana et al. (2005) documented 60 wild edible plants consumed by the

rural communities of Campoo, Northern Spain. The tribes namely Malaarayans,

Malampandarams, Mannars, Paliyans and Uralis in Periyar Tiger Reserve of Kerala

are known to use 46 wild edible plants as a source of food (Sasidharan and Augustine,

2006). Arinathan et al. (2007) enumerated 171 wild edible plants belonging to 67

families consumed by the Palliyans in the reserve forest area of Grizzled Giant

Squirrel Wildlife Sanctuary in Virudhunagar district of Tamil Nadu. Misra et al.

(2008) documented 25 wild leafy vegetables consumed by the local inhabitants of

Nanda Devi Biosphere Reserve. Shtayeh et al. (2008) enumerated 100 wild edible

plants consumed by the local communities in 5 districts in the Palestinian Authority,

PA (Northern West Bank).

11

H. Chemical and Nutritive Evaluation

The information on the usage of several plant species as source of food and

medicine among different primitive tribes in India is well documented (Jam, 1963,

1981, 1984; Prakash, 1998; Ramachandran and Nair, 1981). However information on

chemical composition of ethno food and medicinal plants is meager (Rajyalakshmi

and Geervani, 1994; Matsuse et al., 1999; Vadivel and Janardhanan, 2001a;

Perumalsamy and Ignacimuthu, 2000 and Janardhanan et al., 2002a).

Proximate Composition

For any food stuff, proximate composition provides information about the

contents of crude protein, crude lipid, crude fibre, ash and Nitrogen- Free Extractive

(NFE). In view of all these, in the present study the collected parts of wild plants

consumed by the Paliyans and Pulayans in the study area, Palani Hills have been

subjected to proximate composition.

A considerable number of analyses for proximate composition have been

carried out in the tubers of Dioscorea alata, D. cayenensis, D. esculenta and D.

rotundata (Oyenuga, 1959; Coursey et al., 1960 ; Mitra et al., 1990; Balagopalan

2000); D. alata and D. trflda (Martin and Thompson, 1971); D. bulbfera (Umbreit et

al., 1972) D. alata (Ferguson et al., 1980; Parkinson, 1984; Abraham and Nair,

1984); D. cayenensis and D. rotundata (Kabeerathumma et al., 1985); D.pentaphylla,

D. esculenta, D. bulbfera and D.oppositfolia (Nilegaonkar et al., 1985); D. alata, D.

dumetorum and D. rotundata (Lape and Trechi, 1994); various Dioscorea sp

(Murugasan and Ananthalakshmi 1991; Pramila et al., 1991; Rajyalakshmi and

Geervani, 1994); in the corms of Amorphophallus paronifolicus (Parkinson, 1984;

12

Nair etal., 1999; Seralathan and Thirumaran, 1999) Colocasia esculenta (Houssain et

al., 1983; Parkinson, 1984; Pramila etal., 1991; Aggarwal etal., 1999; Seralathan and

Thirumaran, 1999; Balagopalan, 2000; Daha.1 et al., 2003); A!ocasia macrorrhiza and

A!ocasia indicus (Murugasan and Ananthalakshmi, 1991; Pramila et al., 1991;

Aggarwal et al., 1999); Xanthosoma sagittfolium (Parkinson, 1984; Seralathan and

Thirumaran, 1999; Balagopalan 2000) and in the rhizomes of Sagittaria sagittfolia

and Canna edulis Vima1a, 1995).

Proximate composition has been estimated in some non-traditional leafy

vegetables (Oliveira and Carvaiho, 1975; Bharathi and Umamaheswari, 2001) and in

the leaves of Moringa concanensis (Arinathan et al., 2003).

Proximate composition has been estimated in tribal pulses (wild legumes)

namely Acacia catechu (Rajaram and Janardhanan, 1991a); Abrus precatorius

(Rajaram and Janardhanan, 1992a; Mohan and Janardhanan, 1995a; Vadivel and

Janardhanan, 1999); Alysiocarpus rugosus (Siddhuraju et al., 1992a); Atylosia

scarabaeoides (Arinathan et al., 2003); Bauhinia purpurea, B. racemosa and, B.

vah!ii (Rajaram and Janardhanan, 1991b); B. racemosa (Mohan and Janardhanan,

1994a); B. purpurea (Vijayakumari etal., 1997a); B. vah!ii (Vadivel and Janardhanan,

1999); Cassia a!ata (Ukhun and Ifebigh,1988); C. floribunda (Vadivel and

Janardhanan, 2001a) C. obtusfolia (Crawford et al., 1990; Mohan and Janardhanan,

1995a); Canava!ia ensiformis, C. gladiata and C. maritima (Bressani et al., 1987); C.

ensfonnis and C. g!adiata (Rajaram and Janardhanan, 1992b; Mohan and

Janardhanan, 1994b); C. ensforinis (Vadivel and Janardhanan, 2001b); C. g!adiata

(Arinathan et al., 2003); Entada scandens (Janardhanan and Nalini, 1991;

Vijayakumari et al., 1993b); E. phaseo!oides (Mohan and Janardhanan, 1993a;

13

Siddhuraju et al., 2001); Lablab purpureus var. lignosous (Arinathan et al., 2003);

Mucuna gigantea (Rajaram and Janardhanan, 1991c); M. monosperina (Arulmozhi

and Janardhanan, 1992; Mohan and Janardhanan, 1995b); M. pruriens (Mary

Josephine and Janardhanan, 1992; Siddhuraju et al., 1996a; Vadivel and Janardhanan,

2000a); M. pruri ens var. utilis (Vadivel and Janardhanan, 2000b); Neonotonia wightii

var. coimbatorensis (Arinathan et al., 2003); Parkia roxburghii (Mohan and

Janardhanan,1993a); Parkinsonia aculeata (Rajaram and Janardhanan,1991a);

Phaseolus lunatus (Vadivel and Janardhanan, 1999); Rhyncosia fihipes (Arinathan et

al., 2003); V. unguiculata subsp. dekindtiana, Vunguiculata subsp. unguiculata, V.

vexillata (Carnovale et al., 1991) Vigna capensis and V. sinensis (Mohan and

Janardhanan, 1993b); V. sinensis, V. trilobata and V. umbellata (Vadivel and

Janardhanan, 1999); V. trilobata and V unguiculata subsp. unguiculata (Arinathan

et al., 2003).

Total Soluble Carbohydrate, Starch and Free Amino Acids

Carbohydrates such as soluble sugars and starches are the main energy

yielding substances of the diet.

Total soluble sugar content was estimated in the seeds of Cicer arietinum and

Phaseolus aureus (Goyal and Mathews, 1985). Total starch content was estimated in

the tubers of Manihot esculenta (Oke, 1975); Dioscorea alata, D. esculenta and D.

rotundata (Babu et al., 1990; Sundaresan et al., 1990) D. bulbfera, D. hispida,

D. opposit folia and D. pentaphylla (Rajyalakshmi and Geervani, 1994); in the corms

of Alocasia and Colocasia (Aggarwal et al., 1999); in the pith of Caryota urens

(Rajyalakshmi and Geervani, 1994); in the seeds of Entata scandens (Janardhanan

14

and Nalini, 1991); Pisum sativum (Shinde et al., 1996); Streculia urens and S.foetita

(Kumbhare and Bhargava, 1999).

The contents of total soluble sugar and starches were estimated in the seeds of

Cajanus cajan (Shrivastava and Bajpai, 1981); Canavalia ensfor,nis, C. gladiata, C.

virosa (Rodrigues and Tome, 1991); Vicia faba and Vigna unguiculata (Mnembuka

and Eggum, 1993); Cajanus cajan, Glycine max, Phaseolus vulgaris, Psophocarpus

tetragonolobus, Vigna radiata, V. unguiculata, Voandzeia subterranea (Mnembuka

and Eggum,1995) and Tamarindus indica (Shankaracharya, 1998). The amount of

total soluble sugars and free amino acids were estimated in the seeds of Vigna

umbellata (Singh et al., 1980). The amount of total soluble sugars, starch and free

amino acids were estimated in the seeds of different varieties of Almond (Kumar and

Uppal, 1995).

Niacin and Ascorbic Acid

Niacin or Nicotinic acid is a true anti- pellagra vitamin. Niacin content was

estimated in some wild edible greens (Oliveira and Carvalho, 1975); in the tubers of

Dioscorea bulbfera, D. hispida, D. oppositfolia and D. pentaphylla; in the shoot of

Bambusa arundinacea; in the pith of Caiyota urens and in the seeds of Cajanus

cajan, Dolichos bjflorus, D. lablab, Mucuna pruriens, Vigna catjang and Vigna sp.

(Rajyalakshmi and Geervani, 1994) and Vigna unguiculata subsp. unguiculata

(Arinathan et al., 2003).

Ascorbic acid (vitamin c) is involved in bone and teeth calcification. Ascorbic

acid content was estimated in 13 non—conventional foods including fruits, leaves and

15

grains (Duhan et al., 1992); in the tender leaves of 5 wild edible crucifer species

(Guerrero et al., 1999); in 10 non—traditional leaves collected from Nellore and

Prakasam districts of Andhra Pradesh (Bharathi and Umamaheshwari, 2001); in 5

uncommon leafy vegetables consumed by the tribals of Purnia district of Bihar (Rao

and Vijay, 2002); in 30 indigenous vegetables commonly utilized in the rural areas of

Tanzania (Lyimo et al., 2003) and in 9 less familiar leaves consumed by the tribals of

Udaipur region (Sankhala et al., 2005) and in the seeds of Sterculia foetida and S.

urens (Kumbhare and Bhargava, 1999).

The contents of niacin and ascorbic acid were estimated in the tubers of

Alocasia macrorrhiza and Colocasia esculenta (Pramila et al., 1991); in some wild

edible greens (Sengupta and Pal., 1970) and in the seeds of Chenopodium quinoa

(Ahamed et al., 1998); Atylosia scarabaeoides, Canavalia gladiata, Lablabpurpureus

var. lignosus, Rhyncosia fihipes and Vigna trilobata (Arinathan et al., 2003).

Mineral Composition

Presence of mineral elements in the diet is necessary for life. Some of them

are essential for the formation of structural components of the body and some of them

act as catalyst in many body reactions (Mertz, 1981).

The potential contributions of wild edible plants / seeds to dietary mineral

needs are less known. While some of the seeds are known to be good sources of iron

(Peterkin et al., 1975) others are known to be rich source of potassium, zinc,

magnesium and phosphorus (Consumer and Food Economic Research Division,

1971). To understand the exact mineral composition of the various parts of wild plants

16

consumed by the Paliyans and Pulayans in the study area, Palani Hills a detailed

mineral analysis has been carried out in the present study.

The mineral composition was analaysed in the tubers of Dioscorea alata

(Ferguson et al., 1980; Parkinson 1984); D. esculenta, D. alata and Dioscorea

rotundata (Mitra et al., 1990); D. dumetorum and D. rotundata (Lape and Treche,

1994); D. hispida, D. oppositfolia and D. pentaphylla; in the corms of Alocasia

macrorrhiza and Colocasia esculenta (Pramila et al., 1991; Aggarwal et al., 1999);

Colocasia esculenta and Alocasia sp (Parkinson, 1984; Kabeerathumma et al., 1985;

Sen and Choudhury, 1988; Balagopalan, 2000); in the shoot of Bambusa arundinacea

and in the pith of Caryota urens (Rajyalakshmi and Geervani, 1994); and in the seeds

of Prunus armeniaca (Pramila et al., 1991); Sterculiafoetida and S. urens (Kumbhare

and Bhargava, 1999). 4 edible wild plants consumed by the local residents in the

Western Sahel of Africa were analysed for their mineral composition (Glew, et al.,

2005).

Ten edible leaves consumed by natives of Mozambique were analysed for their

sodium, potassium, calcium, magnesium and phosphorus contents (Oliveira and

Carvaiho, 1975). 13 non—conventional foods including fruits, leaves and grains

consumed in various parts of the Indian subcontinent were analysed for their mineral

composition (Duhan et al., 1992). 6 non—conventional leafy vegetables consumed

largely by the rural populace of Nigeria were analysed for mineral composition

(Barminas et al., 1998). The tender leaves of 5 wild edible crucifer species were

analysed for their mineral composition. (Guerrero et al., 1999). 5 wild edible leaves

consumed by natives of Sikkim Himalaya were analysed for mineral composition

(Sundriyal and Sundriyal, 2001). 5 uncommon leafy vegetables consumed by the

17

tribals in Purnia district of Bihar were investigated for their iron and calcium contents.

(Rao and Vijay, 2002). 9 less familiar leaves consumed by the tribals of Udaipur

region were investigated for their iron and calcium contents (Sankahala et al., 2005).

Mineral composition was analysed in wild legumes such as Acacia catechu

(Rajaram and Janardhanan, 1991a); Abrus precatorius (Rajaram and Janardhanan,

1992a; Mohan and Janardhanan, 1995a; Vadivel and Janardhanan, 1999); Bauhinia

purpurea, B. racemosa and B.vahlii (Rajaram and Janardhanan, 1991b); B.

malabarica (Vijayakumari et al.. 1993a); B.racemosa (Mohan and Janardhanan,

1994a); B.purpurea (Vijayakumari et al., 1997a); B. vahlii (Vadivel and Janardhanan,

1999); Cassia alata (Ukhun and Ifebigh,1988); C. obtusfolia (Vijayakumari et al.,

1993b; Mohan and Janardhanan, 1995a); C. floribunda (Vadivel and Janardhanan,

2001a); Canavalia ensfonnis, C.gladiata (Bressani et al., 1987; Rodrigues and

Tome,1991; Rajaram and Janardhanan, 1992b; Mohan and Janardhanan, 1994b); C.

martima (Bressani et al., 1987); C.virosa (Rodrigues and Tome, 1991); C. ensfonnis

(Vadivel and Janardhanan, 2001b); Entada scandens (Janardhanan and Nalini,1991;

Vijayakumari et al., 1993b); E.phaseoloides (Mohan and Janardhanan, 1993a;

Siddhuraju et al., 2001); Glycine max (Mnembuka and Eggum, 1995); M gigantea

(Rajaram and Janardhanan, 1991c); M monosperma (Arulmozhi and Janardhanan,

1992; Mohan and Janardhanan, 1995b); M pruriens( Mary Josephine and

Janardhanan, 1992; Vadivel and Janardhanan, 2000a); Mucuna utilis and V. sinensis

(Mohan and Janardhanan,1993b); V. sesquipedalis, V. sinensis and V. umbellata

(Rajaram and Janardhanan, 1990); V. trilobata (Siddhuraju et al., 1992b; Vadivel and

Janardhanan, 1999) V. unguiculata (Mnembuka and Eggum, 1993,1995) and in V.

umbellata (Mohan and Janardhanan, 1994c; Vadivel and Janardhanan, 1999).

18

Anti-nutritional Factors

Many plants have the capacity to synthesize various chemical substances that

are known to have harmful effects on human or animals, which eat them. Food

particularly of plant origin contains a wide range of ant nutritional factors which

interfere with the assimilation of nutrients contained in them and cause adverse

physiological effects. They interfere with the utilization of other nutrients like

protein, minerals like iron, zinc, calcium and iodine. In food legumes the presence of

some well-defined anti-nutritional factors has been documented (Liener, 1962, 1976,

1980; Nowacki, 1980; Etzler, 1985; Gupta, 1987).

Quantification of various anti—nutritional factors and their elimination have

been carried out by several investigators (Liener, 1962; Moseley and Griffiths, 1979;

Achinewhu, 1983, Vinh et al., 1985; Kotaru et al., 1987; Egbe and Akinyele, 1990;

Babu 1990; Mohan and Janardhanan, 1993 a, b; Vijayakumari et al., 1995;

Arinathan, 2003).

Total Free Phenols and Tannins

Phenols, the aromatic compounds with hydroxyl groups are wide spread in

plant kingdom. They occur in all parts of the plants. Several investigators have

confirmed the presence of total free phenols in various under exploited wild tubers,

corms and legumes (Adelusi and Ogundana, 1987; Babu et al., 1990; et al., 1990;

Rajaram and Janardhanan, 1990,1991a,b,c, 1992a; Janardhanan and Nalini, 1991;

Siddhuraju et al., 1992 a,b; Mary Josephine and Janardhanan, 1992; Arulmozhi and

Janardhanan, 1992; Vijayakumari et al., 1993b; Mohan and Janardhanan, 1993a,b,

1994a,b, 1995a,b; Vadivel and Janardhanan,1999, 2000a, 2001a).

19

The content of total free phenols was estimated in tubers of Dioscorea sp

(Kamick, 1971; Osuji,1985); Ipomoea batatus and Solanum tuberosum (Adelusi and

Ogundana, 1987); Manihot esculenta (Babu etal., 1990) and in the corm of Colocasia

esculenta (Adelusi and Ogundana, 1987).

Tannins are water soluble polyphenols and they may be carcinogenic. They

are condensed polyphenolic compounds which are widely distributed in plants.

Tannins are documented to be present in the tubers of Dioscorea cayenensis and

D.rotundata, D.esculenta (Udoessien and Ifon, 1992). Several investigators have

demonstrated the presence of these polyphenolic compounds in various seeds

(Ronnenkamp, 1977; Ma and Bliss, Griffiths and Moseley, 1980; Lackman et al.,

1980; Kaushal and Bhatia, 1982; Rao and Deosthale, 1982; Griffiths, 1983; Bressani

et al., 1983; Barroga et al., 1985; Janardhanan and Lakshmanan, 1985; Cabrera and

Martin, 1986; Kotaru et al., 1987; Maihotra et al., 1988; Egbe and Akinyele,1990;

Rajaram and Janardhanan, 1991a; Mary Josephine and Janardhanan, 1992; Arulmozhi

and Janardhanan, 1992; Siddhuraju et al., 1992a,b, 1995a,b,c; Vijayakumari et al.,

1993b; Mohan and Janardhanan 1993a,b, 1994a,b, 1995a,b, Kumbhare and Bhargava,

1999; Vadivel and Janardhanan, 1999, 2000a, 2001a; Ofori etal., 2001; Arinathan et

al., 2003). Tannins and phenols are present in the tubers of coleus, arioids and yams

(Balagopalan 2000).

L-DOPA (3,4- Dthydroxyphenylalanine)

L-DOPA (3,4-dihydroxyphenylalanine), a non-protein amino acid was first

isolated by Guggenheim about 70 years ago from the fruits of Vicia faba (Brain,

1976). Several investigators (Bell and Janzen, 1971; Daxenbichler et al., 1971; Rai

20

and Saidu, 1977; Pieris et al., 1980; Janardhanan and Lakshmanan, 1985;

Janardhanan and Nalini, 1991; Rajaram and Janardhanan 1991c, 1992b; Arulmozhi

and Janardhanan, 1992; Mary Josephine and Janardhanan, 1992; Siddhuraju et al.,

1992b; Mohan and Janardhanan, 1995b; Vadivel and Janardhanan, 2000b and

Arinathan 2003) have documented the presence of fairly high levels of L-DOPA in

some tribal pulses. The presence of high levels of L-DOPA in the uncooked

seeds of Mucuna utilis has been implicated to be responsible for causing skin

eruptions and an increase in body temperature of the consuming tribal people,

Kanikkars (Jebadhas, 1980).

Hydrogen Cyanide

The nutritive value of tubers and leaves is affected due to the presence of

cyanogenic glycosides, linamarin and lotustralin which form highly toxic hydrogen

cyanide on coming into contact (due to injury, infection, cutting, grinding processing,

etc.) with the enzyme linamerase (Balagopalan, 2000).

The information on hydrogen cyanide content of the tribal food plants is

relatively meagre. Some investigators have reported the presence of hydrogen cyanide

in various wild food plants (Oke, 1975; Kurian et al., 1976; Cooke and De La Cruz,

1982; Okolie and Ugochukwu, 1989; Nambisan and Sundaresan, 1990; Udoessien and

Non, 1992; Nambisan and Malathi, 1993; Vijayakumari et al., 1995; 1997a;

Siddhuraju et al., 2001; Arinathan et al., 2003)

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