**1.5. Plant-based drugs**

In the ancient times, plants served humankind as the source of all drugs with most therapeutic agents provided by the higher plants. The World Health Organization estimated that about 3.5–4 billion people in the world depend on traditional medicine as sources of drugs for their primary health care (80% of people in the developing countries and 85% of traditional medicine rely on plant extracts) [12]. Plant-derived drugs represent 25% of the prescription of drugs in the market in the United States of America [13], and from 1983 to 1994, 39% of the new approved drugs were of natural origin; this included original natural products, semisynthetically derived products from natural origin and synthetic products based on models from natural products [14]. From 87 approved anticancer drugs, a survey revealed that 62% were of natural origin or is derived from modeling of the natural product parents [14]. Paclitaxel, vincristine, podophyllotoxin (a natural product precursor), and camptothecin (a natural precursor for water-soluble derivatives) are among those clinically useful drugs.

**Botanical (species)** 

**Family name**

**Local name(s)**

**Common names**

**Parts used**

**Medicinal use(s)**

**name**

1 2 3 4 5 6 7 8 9 10 11

*Buchholzia coriacea*

Sterculiaceae

Uworo, obi-ata

Wonderful kola

Fruit, bark

*Bambusa vulgaris*

Poaceae

Oparun, atosi

Bamboo

Leaves, young

Gonorrhea, abortifacient, skin rashes of HIV/

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AIDS, emmenagogue, anthelmintic

Antimicrobials, anthelminthic, ulcer, fibroid,

dysmenorrhea, chest pains, respiratory

11

disorders

shoots

*Azadirachta indica*

Meliaceae

Dongo-yaro,

Neem tree

Leaves, stem bark,

seeds

eke-oyibo

*Aloe vera*

Liliaceae

Ahon erin

Barbados aloe

Leaves' juice

*Allium sativum*

Liliaceae

Aayu

Garlic

Bulb

*Allium cepa*

Liliaceae

Alubosa, albasa,

Onion

Bulb, leaves

yabase, albasa gudaji

*Alafia barteri*

Apocynaceae

Agbari etu

Alafia chewing stick,

Roots, leaves

guinea fowl's crest

*Aframomum melegueta*

Zingiberaceae

Atare, ata-ire,

Alligator pepper, grains

Leaves, seeds

of paradise

itaye, citta, ose oji,

gyandamaryaji

*Adansonia digitata*

Bombacaceae

Igi-ose, kukaa, ose,

Baobab

Leaves, fruit, pulp,

Malaria, skin diseases, caries, asthma,

diarrhea, bladder diseases, antimicrobial

Anemia, wounds, stimulant, coughs, malaria,

rheumatism, anthelmintics, smallpox, chicken

Eye infections, toothache, sickle cell anemia,

rheumatic pains

Skin diseases, throat infection, tumor, weak

erection, cough, antidiuretic, anthelmintic,

rubefacient

Asthma, anthelmintic, antibiotic, blood

tonic, malaria, ringworm, antimicrobials,

emmenagogue, flatulence

Purgative, guinea worms, hair care, skin

diseases, amenorrhea, immune booster,

diabetes, breast cancer

Malaria, syphilis, jaundice, eczema, laxative,

ringworm, skin disease, sore throat,

Phytochemicals—God's Endowment of Curative Power in Plants

anthelmintic

pox

bark

kulambali

*Acalypha fimbriata*

Euphorbiaceae

Jinwinini, kandiri

Acalypha

Leaves

*Abelmoschus esculentus*

Malvaceae

Ila, okweje, kubewa

Okra, lady's finger

Fruit, seeds

Fevers, dysentery, catarrhal, antispasmodic,

tonic, gonorrhea

Syphilis, ulcers, asthma, anthelmintic,

antimicrobial


in use in one form or the other traditionally. No doubt, the plant kingdom is rich in diverse

ous uses of some common medicinal plants from Nigeria used for treating various diseases

Medicinal plants should be harvested at the appropriate seasons as their medicinal properties vary with respect to different seasons. The medicinal properties may be located and restricted to a particular part of the plant, and the medicinal attributes is also affected by the age of the plant. A medicinal plant of a particular age for drug processing should therefore be harvested at the correct season of the year to prevent loss or changes in its phytochemical constituents. The period of storage in shade or sun and the geographical locations of the medicinal plants

Medicinal plants are very rich in chemical compounds which they produce for their own defense and are known as secondary metabolites (phytochemicals) and their medicinal poten

cies are attributed to these chemical compounds [11]. A medicinal plant may contain a mixture of different phytochemicals, for example, saponins, which have ability to lower cholesterol; alkaloids which are rich in nitrogenous compounds and are stimulants; tannins which are natural antibiotics; anthraquinones used as laxative and dye; cardiac glycosides which are good cardiovascular drugs; and phenols and flavonoids which are rich in antioxidants. The ability to identify these biologically active compounds in a medicinal plant serves as a guide in its quality control and dose determination. Most medicinal plants in Nigeria have not been screened for their complete phytochemical compositions, and this would help in their dose determination and standardization. The entire world has more than 250,000 species of higher plants gathered from conservative studies, and only an insignificant percentage has been

In the ancient times, plants served humankind as the source of all drugs with most thera

synthetically derived products from natural origin and synthetic products based on mod

els from natural products [14]. From 87 approved anticancer drugs, a survey revealed that 62% were of natural origin or is derived from modeling of the natural product parents [14]. Paclitaxel, vincristine, podophyllotoxin (a natural product precursor), and camptothecin (a natural precursor for water-soluble derivatives) are among those clinically useful drugs.

peutic agents provided by the higher plants. The World Health Organization estimated that about 3.5–4 billion people in the world depend on traditional medicine as sources of drugs for their primary health care (80% of people in the developing countries and 85% of traditional medicine rely on plant extracts) [12]. Plant-derived drugs represent 25% of the prescription of drugs in the market in the United States of America [13], and from 1983 to 1994, 39% of the new approved drugs were of natural origin; this included original natural products, semi

9, 10]. The vari

.






array of plants whose medicinal attributes (potencies) are yet to be unraveled [

highlighting the parts of the plants used are represented in **Table 1**

10 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

also play important roles in the medicinal properties of the plant [11].

exhaustively studied for their potentials as drug sources [11].

**1.5. Plant-based drugs**

**1.4. Identification and standardization of active principles in medicinal plants**

**1.3. Harvest of medicinal plants**


**Botanical (species)** 

**Family name**

**Local name(s)**

**Common names**

**Parts used**

**Medicinal use(s)**

**name**

22

*Entandrophragma* 

Meliaceae

Ijebo, jebo

Cedar mahogany

Stem bark

Stimulant, gastrointestinal disorders, cough,

diabetes, fever, black tongue

Asthma, catarrh, cough, hay fever,

conjunctivitis, anthelmintic, amoebic

dysentery, increased lactation and breast

shape, antispasmodic, hypertension

Piles, jaundice, impotence, antipyretics

*cylindricum*

23 24 25 26 27 28 29 30 31 32

*Lagenaria breviflorus*

Cucurbitaceae

eso-ito

Tagiri, eso-itagiri,

Pseudocolocynth

Root, fruit

*Kigelia africana*

Bignoniaceae

Pandoro, iyan,

Sausage tree

Leaves, stem, root,

bark, fruits,

rawuya, uturubein

*Khaya ivorensis*

Meliaceae

Oganwo, ono,

African mahogany

Stem, root, barks

Malaria, anemia, skin diseases, jaundice,

arthritis, anthelmintic, emmenagogue

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Kidney disorders, rheumatism, cough,

malaria, spleen infection, dysentery,

gonorrhea, astringent, leucorrhoea

Anthelmintic, diabetes, purgative, small pox,

abortifacient, chicken pox, lumbago, cathartic

13

madachi

*Jatropha curcas*

Euphorbiaceae

Lapalapa, botuje,

Physic nut

zugu, oluluidu

*Irvingia gabonensis*

Irvingiaceae

Oro (ogbono)

Wild mango, bread tree

Fruits, seeds

Weight loss, antiulcer, spleen infection

(kernel), leaves

Seed, stem, leaves,

Eczema, ringworm, scabies, whitlow, fever,

guinea worm, herpes, irregular menstruation,

Phytochemicals—God's Endowment of Curative Power in Plants

smallpox, convulsion

roots, sap

*Ipomoea batatas*

Convolvulaceae

Anamo, odukun,

Sweet potato

kunkundukun,

dankali,

ekomako, jioyibo

*Hibiscus rosa-sinensis*

Malvaceae

Kekeke

Garden hibiscus

Leaves, stem, flower

Influenza, appendicitis, hypertension, asthma,

stomach upset, antipyretic, oligospermia

Boils, diabetes, wounds, bronchial asthma,

antimicrobials, purgative, breast swelling

buds

Leaves, tuber

*Garcinia kola*

Guttiferae

Orogbo

*Funtumia elastica*

Apocynaceae

Ire

Silk rubber tree, wild

Stem, twigs, latex

rubber

Bitter kola

Seeds, roots, fruits,

Antimicrobial, bronchitis, cough, dysentery,

toothache, fever, throat and respiratory

ailments, liver disorders, evacuant, headache,

anticancer

stem bark

*Euphorbia hirta*

Euphorbiaceae

Emi-ile, iroko-iju,

Asthma weed

Whole plant,

exudate

oro-elewe


**Botanical (species)** 

**Family name**

**Local name(s)**

**Common names**

**Parts used**

**Medicinal use(s)**

**name**

12

*Butyrospermum* 

Sapotaceae

Emi-emi, emi, osisi,

Shea butter tree

Seeds

Nasal decongestion, anthelmintic,

hypertension, diuretic

ka'danya

*paradoxum* (*Vitellaria* 

*paradoxa*)

13 14 15 16 17 18 19 20 21

*Elaeis guineensis*

Palmae

Igi-ope, ope

*Datura metel*

Solanaceae

Ajegun-eegun

Devil's trumpet, hairy

Leaves

thorn apple

Red oil palm

Root, bark, kernels,

Diarrhea, asthma, measles, mental disorders,

palm oil

malaria

*Daniellia oliveri*

Leguminosae

Iya

African copaiba, balsam

Gum, bark

tree

*Cocos nucifera*

Palmae

Agbon

Coconut palm

Bark, root, nuts

Bronchitis, migraine, dysentery, antiseptic,

toothache, hair loss, uterine disease,

emollient, diuretic, laxative, anthelmintic,

Toothache, astringent, diarrhea, dysentery,

urinary infection

Asthma, convulsion, venereal diseases

liver ailment

*Citrus aurantifolia*

Rutaceae

Osan-wewe,

Lime, swing

Leaves, stem, root,

Fever, hypertensive recipe, jaundice,

gonorrhea, measles, abdominal ulcer,

flavoring agent, cough, scurvy, toothache,

anthelmintic

fruit

dankabuya, afotanta,

epe nkirisi

*Ceiba pentandra*

Bombacaceae

Araba

White silk cotton tree

Flowers, leaves,

bark, exudate

*Catharanthus roseus*

Apocynaceae

Apabida pupa

Rose periwinkle

Leaves, whole plant

Diabetes, antileukemic properties, dysentery,

hypertension, menorrhagia, antitumor

Fever, syphilis, gonorrhea, diabetes, emetic,

astringent, asthma, menorrhagia, emollient,

demulcent

*Carica papaya*

Caricaceae

Ibepe, ojo, gwanda

Pawpaw

*Cannabis sativa*

Cannabaceae

Igbo

Indian hemp

Leaves, female

Diarrhea, sores, dandruff, sedative,

gonorrhea, whooping cough, migraine,

inflorescence, seeds,

stem, twigs

Leaves, seeds, fruits

Amoebic dysentery, syphilis, gonorrhea,

abortifacient, diabetes, roundworms,

12 Phytochemicals - Source of Antioxidants and Role in Disease Prevention

convulsion, malaria, mental disorder, papain

enzyme as meat tenderizer

dyspepsia


Some common medicinal plants from Nigeria used for treating various diseases.

These substances contain properties which are essential as new chemotherapeutic agents useful for treatment in the hospitals. There are some new approaches to drug discovery, such as combinatorial chemistry and computer-based molecular modeling design, and none of them can replace the role of natural products in drug discovery and development. Examples of

Phytochemicals—God's Endowment of Curative Power in Plants

http://dx.doi.org/10.5772/intechopen.77423

15

Most herbs exhibit their effects on a variety of constituents, and the idea of synergy within and between them is gaining acceptance [15]. Most herbal medicines are not well documented to prove whether they are acting truly in a synergistic way or by additive effects. It is usually difficult to clinically evaluate herbal preparations without the knowledge of their synergistic effects. Biological activity may be absent in the crude drugs but may contain some components that can enhance their active components' potency. One of such examples is St. John's wort (*Hypericum perforatum*, family Hypericaceae), a clinically proven herb which has efficacy as an antidepressant. Hypericins responsible for its activity was found to be very weak, and impurities in the fraction used gave the additional results which suggest multiple (polyvalent) and synergistic effects. St. John's wort thus represents a good example of an herb which may exhibit synergism and polyvalent action [16]. The use of combinations of herbs can also result in synergism or enhancement of activity of herbal drugs. In case of multiple herb extracts, some of the herbs enhance the potency of the real effective herb, and in some cases, their constituents could reduce the toxic effects of the main herb, resulting in a safe herbal combination tolerable for consumption by the

Phytochemicals are chemicals found in plants that protect plants against bacteria, viruses, and fungi. Eating large amount of brightly colored fruits and vegetables, whole grains/cereals, and beans containing phytochemicals may decrease the risk of developing certain cancers as well as diabetes, hypertension, and heart disease. The actions of phytochemicals vary by the type of the food and the color. They may act as antioxidants or nutrient protectors or prevent carcinogens from forming. The term phytochemical refers to a wide variety of compounds made by plants but is mainly used to describe those compounds that may affect human health. Scientists have identified thousands of phytochemicals, although only a small fraction has been studied closely. Some common examples of phytochemicals include betacarotene (with other carotenoids), vitamin C, vitamin E, and folic acid [18]. Phytochemicals have shown various physiological actions [19, 20]. Among the numerous phytochemicals in

These are the largest group of secondary metabolites made of ammonia compounds comprising basically nitrogen bases synthesized from amino acid building blocks having various radicals substituting one or more of the hydrogen atoms in the peptide ring, containing mostly

plant-based drugs are artemisinin, gingerosome, and quinine.

human system [17].

**1.8. Alkaloids**

**1.7. Phytoconstituents in medicinal plants**

existence are the following with their usefulness:

**1.6. Synergy in relation to pharmacological action of phytomedicine**

**Table 1.** These substances contain properties which are essential as new chemotherapeutic agents useful for treatment in the hospitals. There are some new approaches to drug discovery, such as combinatorial chemistry and computer-based molecular modeling design, and none of them can replace the role of natural products in drug discovery and development. Examples of plant-based drugs are artemisinin, gingerosome, and quinine.
