Phytochemical Screening of Some Spices Used as Condiment in Kano, North western Nigeria

Introduction

Natural products have been an integral part of ancient traditional medicine systems, e.g. Chinese, Ayurvedic and Egyptian [1]. Over the years, they have assumed a very central stage in modern civilization as natural source of chemotherapy as well as amongst scientist in search for alternative sources of drugs. According to the World Health Organization [2], a medicinal plant is any plant which in one or more of its organs, contains substances that can be used for therapeutic purposes, or which are precursors for chemo-pharmaceutical semi synthesis [2]. Such a plant will have its parts including leaves, roots, rhizomes, stems, barks, flowers, fruits, grains or seeds, employed in the control or treatment of a disease condition and therefore contains chemical components that are medically active [3]. Phytochemicals are bio- active chemicals of plant origin. They are regarded as secondary metabolites because the plant that manufactures them may have little need for them. They

are naturally synthesized in all parts of the plant body; bark, leaves stem, root, flower, fruits, seeds, etc. i.e. any part of the plant body may contain active components Spices, which include leaves (coriander, pepper mint), buds (clove), bulbs (garlic, onion), fruits (red chili, black pepper), stem (cinnamon), rhizomes (ginger) and other plant parts, have been defined as plant substances from indigenous or exotic origin, aromatic or with strong taste, used to enhance the taste of foods [4, 5]. Spices are products of plants (seeds, kernels, bulbs, stalk, roots, fruits, bark, leaves, pods or buds) which are used in various forms such as fresh, ripe, dried, broken or powdered mostly to contribute to colour, taste, aroma, flavour and pungency of food Spices are widely used as condiments and ingredients in food preparation [6, 7]. In Nigeria, some spices are useful in the preparation of certain soups which are delicacies and also recommended for rapid relief of ailments such as cold, malaria fever, etc [8]. These spices are also said to be therapeutically useful in the management of stomach ache, leprosy, cough, and loss of appetite, rheumatoid pain, convulsion and inflammation [9]. There is an increasing interest both in the industry and in scientific research for spices and aromatic herbs because of their strong antioxidant and antimicrobial properties, which exceed many currently used natural and synthetic antioxidants. These properties are due to many substances, including some vitamins, flavonoids, terpenoids, carotenoids, phyto estrogens, minerals, etc. and render spices and some herbs or their antioxidant components as preservative agents in food [10]. The study was aimed to evaluate the phyto chemical composition of seven selected spices widely use in Kano, Northwestern Nigeria namely Zingiber officinale, Allium cepa, Allium sativa, Mentha piperita, Ocimum gratissimum, Piper nigrum and Syzygium aromaticum.

Discussion

These secondary metabolites contribute significantly towards the biological activities of medicinal plants such as hypo glycemic, anti-diabetic, antioxidant, antimicrobial, anti-inflammatory, anti-carcinogenic, anti-malarial, anti cholinergic, anti-leprosy activities etc [3]. This research work was conducted on the seven selected medicinal plants used as spices in Kano, North western Nigeria to determine the qualitative and quantitative of some phyto chemical present in them. The results shows that phyto chemical constituents of the selected spices include; terpenoids, flavonoids, alkaloids, reducing sugars, steroid, glycoside, phenol, Anthra quinones, saponin and tannin. Several studies were conducted to determine phyto chemical constituents of spices [13, 14, 15, 16, 17]. These plants used as food preservatives and folk medicines. So, their value is depend on the phytochemicals they possess [18]. The spices, herbs, plant extracts and their phyto-constituents have been reported for anti-inflammatory, anti diarrheal, antimicrobial, antioxidant and insecticidal activities [19]. According to this study, Alkaloid is present in all the extracts except Mentha piperita extract. Alkaloids comprising a large group of nitrogenous compounds are widely used as cancer chemotherapeutic agents, anaesthetics and Central Nervous Stimulants [20, 21]. Alkaloids are known to play some metabolic roles and control development in living system [22]. It also interferes with cell division, hence the presence of alkaloids in ginger, clove, onion, garlic and black pepper could account for their use as antimicrobial agents. Aboaba et al. had reported that the antimicrobial properties of substances are desirable tools in food spoilage and food safety [23]. This suggests that the spices extracts which have been confirmed to contain alkaloids may also be useful as preservatives in food. Flavonoid, terpenoid and anthrax quinone are present in all the extract according to this study. Terpenoids have been found to be useful in the prevention and therapy of several diseases, including cancer. Terpenoids are also known to possess antimicrobial, antifungal, antiparasitic, antiviral, anti-allergenic, antispasmodic, anti hyperglycemic, anti inflammatory and immune modulatory properties [24]. Flavonoids are also present in all the extracts as a potent water-soluble antioxidant and free radical scavenger, which prevent oxidative cell damage and also have strong anticancer activity [25, 26]. It also helps in managing diabetes induced oxidative stress. Saponin and tannin were also present in all the extracts. Saponins protect against hypercholesterolemia and antibiotics properties [27]. In addition, it has been documented that saponins have antitumor, antioxidant and anti-mutagenic activities and can lower the risk of human cancers by inhibiting the growth of cancer cells [28, 29]. The growth of many fungi, yeast, bacteria and viruses was inhibited by tannins [30]. Tannins are used as antiseptic and this activity is due to presence of the phenolic group. Tannin rich medicinal plants are used as healing agents in a number of diseases. In Ayurveda, formulations based on tannin-rich plants have been used for the treatment of diseases like leucorrhoea, rhinnorhoea and diarrhoea [3]. According to the present study, steroid is present in most of the extracts. Steroids are importance in pharmacy as they possess compounds like sex hormones and can be used for drug production [18].

The phyto chemical content of the aqueous extract of the studied spices in this study is presented in (Table 3). Alkaloids were found to be the most abundant phyto chemical in all the spices. Zingiber officinale (12.30%) Allium cepa (11.30%), Allium sativa (7.20%), O. gratissimum (10.7%), S. aromaticum (9.60%), P. nigrum bird pepper (13.10%) while absent in mentha piperita. Flavonoid tannin and saponin are available at some extend in most of the plants under study.

Conclusion

The results of this study showed that the selected seven spices consist of many useful phytochemical compounds having important biological properties such phytochemicals include terpenoids, flavonoids, alkaloids, reducing sugars, steroid, glycoside, phenol, Anthraquinones, saponin and tannin. The study also revealed that Alkaloids was the most abundant phytochemical in all the spices except Mentha piperita. Therefore, the above plants extract could be explored for its highest therapeutic efficacy by pharmaceutical companies in order to develop safe drugs for various ailments. It is recommended that effort should be made to exploit the biomedical applications of these spices due to the presence of such bioactive constituents for full utilization.

Acknowledgement

The authors wish to acknowledge to Technical staff of Departments of Pharmaceutical technology and those of Science Laboratory Technology (SLT), School of Technology Kano for the use of Laboratory facilities.