Castor plant (Ricinus communis) belonging to the family of Euphorbiaceae, is a perennial crop. Its seed has been reported to contain several compounds such as Oils, fatty acids, oleic acid, ricinoleic acid, sterols, alkaloids; saponins anthraquinones, proteins; ricin, and ricinine. Some of the compounds present in castor have been reported to be insecticidal on Okro black (Podagrica sjostedti),
Fresh fruits of Azadirachta indica were collected, air dried, depulped, pulverized and defatted. It contents were extracted using acidified aqueous extraction. The percentage yield of extract was determined followed by chemical analysis including IR, UV, HPLC and GC of the extract. The insects (okro black) were collected with sweeping net, and then dewinged. The insects were divided into 2 groups. One group was homogenized using phosphate buffer (pH 7.4), while the second group was homogenized using Tris – HCl buffer (pH 7.8). Homogenates were subjected to cold centrifugation at 10,000 x g for 10 mins. The phosphate buffer homogenate was used for determination of the activities of superoxide dismutase (SOD), Catalase (CAT) and acetylcholinesterase (AChE) with different concentration of neem extract, cypermethrin and chlorpyrifos. The Tris – HCl buffer activity of carboxylesterase (CES) with different concentration of neem extract, cypermethrin and chlorpyrifos were also determine using spectrophotometric analysis.
It was discovered from the chemical analysis that the castor contains Ricin, Ricinine, Ricinoleic acid, octadecanoate etc. according to the result obtained from Infra-Red spectroscopy and Gas chromatography. The in-vitro analysis also showed that, at certain concentration of the aqueous extract, the activity of carboxylesterase, Superoxide dismutase, in Podagrica sjostedti was is reduced. The dewinged insects were divided into 2 groups, one group was homogenized using phosphase buffer (PH7.4) while the second group was homogenized using this HCL buffer (PH 7.8). Homogenates were subjected to cold centrifugation at 10,000xg for 10 mins.
The phosphate buffer homogenate was used for spectrum determination the activities of SOD, CAT and AChE in with difference concentration of castor extract cypermethrin and chlorpyrifos. The HCl buffer homogenate was used to determine the activities of CES with different concentration of castor extract, cypermethrin, spectrophotometrically and chlorpyrifos.
According to the result obtained from the biochemical assay. (i.e reduction in the in-vitro carboxylesterase activity of the insect homogenated) it can be inferred that the aqueous extract of Ricinus communis posses some insecticidal activity.
1.0 INTRODUCTION AND LITERATURE REVIEW
Castor (Ricinus communis L.) is a species of flowering plant in the spurge family (Euphorbiaceae) which contains a vast number of plants mostly native to the tropics. It belongs to a monotypic genus Ricinus and sub-tribe Ricininae. The plant’s origin is obscured by its wide dissemination in ancient times, and the ease and rapidity of its establishment as a native plant. However, it appears indigenous to eastern Africa especially the Ethiopian areas (Weiss, 1983). Castor was one of the oldest cultivated crops before being abandoned in many countries in world. The crop is now widely revived as an agricultural solution for all tropical and subtropical regions, addressing the need for commercial crops with low input costs and viable returns (Gana et al., 2013). For instance, several African countries are now diversifying their economic resources and efforts are being intensified on revamping the agricultural sector in order to achieve sustainable economic development. Recently, Nigerian Government called for revival of some industrial crops and among them was Castor oil plant (Salihu, et at., 2013).
Castor is an important oilseed crop great utilitarian value in industry, pharmaceutical and agricultural sectors. Castor is seen as an ideal for agricultural revenue-generated produce, which as a potential to become the premier vegetable oil for industries across the globe. The high potential yield and unique fatty acid composition allow castor oil to produce economically competitive feedstock needed for production of premium quality biodiesel, short chain aviation fuels, derived fuel lubrication additive and very high value biopolymers (Gana et al., 2013). Castor oil is considered superior to petrochemical ones due to its physical properties and eco-friend status. In the last couple of years, demand for castor oil as kept increasing in the international market, assured by more than 700 uses, ranging from medicine and cosmetics of biodiesel, plastic and lubricants. Since castor is not used as food and can be grown productively on marginal lands, it present a unique opportunity to expand industrial vegetable oil production in Africa. Castor provides opportunities in all aspects of agribusiness ranging from crop production, seed supply, agrochemicals, breeding, farm machinery, distribution, processing, marketing and retails sales (NCRI, 2013).
1.2 STUDY RATIONALE
Castor plant has been known to contain ricinine, recinolic acid octadeaconate and ricin etc. which act as an insecticidal. Previous studies have not reported the effect of the castor seed kernel extract on the biochemical enzymes present in Podagrica sjostedti. The present study has therefore focus on the chemical characterization of castor seed kernel extract and its in vitro effects on the activities of superoxide dismutase (SOD), catalase (CAT), carboxyl esterase (CES), and Acetylcholinesterase (AChE) in okro black (Podagrica sjostedti).
This research study aims at investigating the effects of castor plant extracts on insecticidal compounds.
1.3 STUDY OBJECTIVES
- To extract insecticide agents from castor (Ricinus communis L) seed using acidified aqueous extraction.
- To analyze the presence of insecticidal agents in the acidified aqueous extract of Ricinus communis seed using the following techniques
- Infrared (IR) spectroscopy
- Ultraviolet (UV) spectroscopy
- High performance liquid chromatography (HPLC)
- Gas chromatography (GC)
- To investigate the potentials of the Ricinus communis seed acidified aqueous extract on the following enzyme present in the named insect.
(a) Superoxide dismutase (SOD)
(b) Catalase (CAT)
(c) Acetylcholine esterase (ACE)
(d) Carboxyl esterase (CES)
1.4 LITERATURE REVIEW
1.4.1 CASTOR PLANT (RICINUS COMMUNIS)
The plant produces castor seeds that contain up to 50 % castor oil by weight. The oil can easily be extracted from castor seeds have found its use in a several of sectors such as medicine, chemical industry and in other technologies (Ogunniyi, 2006). The demand for castor oil and its products in the world market has been on the steady (Ogunniyi, 2006) partly due to their renewable nature, non-competition with food, biodegradability, low costs, and eco-friendliness. It is now estimated that the oil has over 700 industrial uses and the uses keeps on increasing (Ogunniyi, 2006).
Castor oil, like other seed oils, is extracted from the ripe or mature seeds of the plant after sun drying, and following a sequence of seed processing operations that may include dehulling, pod or seed coat removal, winnowing, sorting, cleaning, grinding or milling, preheating etc. (Gana et al., 2013). Oil extraction is usually achieved by mechanical expression or solvent extraction, or both. Average oil content for all castor seed varieties is about 46-55% oil by weight (Ogunniyi, 2006) actual yield depending on particular seed variety, geographical origin/climatic conditions, and on the oil extraction method(s) used. However, unlike castor seeds which have been widely reported as containing the toxic glycoprotein ricin, the toxic alkaloid ricinine and toxic castor bean allergen (CBA), castor oil is non-toxic, as these toxic ingredients are not carried along with the oil during extraction ICOA, 2013)
22.214.171.124 GEOGRAPHICAL DISTRIBUTION OF CASTOR PLANT
Castor is a non-edible oil crop which grows throughout the tropics, subtropics and is well adapted in some temperate climates (Salihu et al., 2014). Castor plant (Ricinus Communis) is perennial and grows between 10 and 12 min tropical climates while in temperate climates it is anannual plant with common heights of 1–3 m (Salihu et al., 2014). Formaximum oil yield, the plant needs an environment witha temperature between 293 and 303 K, low humiditythroughout the growing season, and soils that are deep, moderately fertile, slightly acidic, well drained, and sandy loams (Salihu et al., 2014).
126.96.36.199 BOTANICAL DISCRIPTION OF CASTOR PLANT.
Sub Family: Acalyphoideae
Sub Tribe: Ricininae
Species: Ricinus communis L (ICOA, 2013)