EVALUATION OF PHYTOCHEMICAL COMPOUNDS IN Ficus polita LEAVES POWDERS FOR INSECT PEST CONTROL

Pesticidal plants, also referred to as botanical pesticides, have been used for centuries for pest management. The study objectives was to evaluate the phytochemical compounds in F.polita leaves powders and their insecticidal activity on Callosobruchus subinnotatus PIC in stored Bambara groundnut in Gombe through untargeted Gas Chromatography-Mass Spectrometry (GC-MS) using three different extraction solvents (ethanol, methanol and distilled water). Result of the study revealed the presence of various compounds. To mention but few, the ethanol extracts revealed the presence of 2-Methylchrysene (C19H14); Chrysene, 1-methyl(C19H14); Ethyl.alpha.-d-glucopyranoside (C8H16O6); 5,9-Undecadien-2-one, 6,10dimethyl(C13H22O). Methanol extracts showed Alloaromadendrene oxide-(2) (C15H24O); Methyl.beta.-d-galactopyranoside (C7H14O6); Phytol (C20H40O); Ethyl .beta.-d-riboside (C7H14O5). Distilled water extraction revealed Lupeol (C30H50O); 9,19-Cycloergost-24(28)en-3-ol, 4,14-dimethyl-, acetate, (3.beta.,4.alpha.,5.alpha.)(C32H52O2); Lanosterol (C30H50O); [4-(4-Methoxymethylbenzyl) phenyl]methanol (C16H18O2) as compounds with the highest percentage areas. Being cheap and readily available, resources-poor farmers perceive those natural products (botanical pesticides) possessed repellence, anti-feeding and ovipositional deterrence, fumigant or contact activity, growth inhibition etc. Hence, could serve as good alternatives to chemical insecticides.


INTRODUCTION
The fig tree, which is also referred to as Ficus polita and called Durumi in Hausa, Jammeiz alazrak in Shuwa Arabic and Gbanchi bokun in Nupe, all in northern Nigeria, belongs to the family Moraceae (Keays, 1989). Ficus is a large genus in the family Moraceae, is composed of over 1, 000 members of species of terrestrial woody trees, shrubs, vines, epiphytes and hemi epiphytes and is distributed in tropical and subtropical regions. Plants in this genus have occupied many ecological niches, and can be deciduous or evergreen trees, shrubs, herbs, climbers or creepers, and life forms can be free standing trees, epiphytes or semi-epiphytes in crevices, rheophytes or lithophytes (Yinxian et al., 2018;Ronsted et al., 2008 andLoutfy, et al., 2005). Ficus polita, the heart-leaved fig, is a species of fig that is primarily native to tropical areas of East Asia and Africa, they are distributed throughout the world's tropics (van Noort and Rasplus, 2021;Encyclopedia Britannica, 2019). Approximately, 800 species are present in Tropical and Subtropical regions of the world (Adebayo et al., 2009).
Phytochemical investigations of some Ficus species revealed the presence of phenolic compounds as their major components from different parts (leaves, stem wood, branches, stem bark, roots, root bark, fruits, and seeds) (Abdel-Hameed, 2009;Sultana and Anwar, 2008;Veberic et al., 2008;Basudan et al., 2005;Sheu et al., 2005;Salem, 2005;Lee et al., 2002). The presence of a cerebroside named politamide, sitosterol 3-O-b-D-glucopyranoside, betulinic acid, stigmasterol and lupeol have been reported in F. polita, (Kamgaet al., 2010). Although synthetic pesticides can work very well, overuse and misuse of synthetic chemicals has led to considerable human and environmental health problems. Several studies have provided baseline information on many Ficus spp potential validity in the treatment and management of insect pests associated with stored grains. The leaves and stem of F. sarmentosa var. henryi have been reported to posessed insecticide activity (Wang et al., 2011). Liu et al., (2011) reported the leaf extract of F. carica showed the strongest nematicidal activity as 74.3, 96.2, and 98.4% mortality, respectively, within 72 hrs. Kellouche A. (2005) tested the fecundity of female cowpea C.maculatus with powders from the leaves of the fig tree Ficus carica (Moraceae), Eucalyptus globulus (Myrtaceae), olive tree Olea europaea (Oleaceae), and Citrus limon (Rutaceae). The results showed that the effect of these powders slightly affects the fecundity of the females. Control of C.subinnotaus in Bamabara groundnut is largely depends and conducted using conventional synthetic insecticides in the study area, but resistance to organophosphates and other class of the synthetic insecticides has been observed by local farmers. The study was aimed to determine the phytochemical compounds in F.polita leaves powders found in Gombe State and their insecticidal potentials on C.subinnotaus in Bamabara groundnut.

MATERIALS AND METHODS Experimental Site
The study was carried out at the Research Laboratory of Biological Sciences Department, the Federal University of Kashere (FUK), Gombe State, located at a GPS coordinate (DMS) 10° 16´ 44.9040'' N and 11° 10´ 23.0160'' E; Latitude 10.27914; Longitude 11.17306 and Altitude 454m, Gombe, Nigeria.

Collection and Athentication of Plant Materials
Fresh plant materials of F.polita leaves were locally collected in Gombe and suburb subsequently, identified at the herbarium of Biological Sciences Department (specimen voucher number 090), Faculty of Science, Federal University of Kashere (FUK), Gombe State, Nigeria.

Preparation of Plant Materials
All the plant materials collected from F.polita (leaves) were shade dried to a crispy dry condition and thereafter was grounded using pestle and mortar, blended with an electric blender and then sieved through a mesh size of 600µm to obtain fine powders.

Preparation of Crude Extracts of the Plant Materials
A weight of 1.8 kg was obtained from the powdered plant leaves. A 600g portions of the powdered leaves were soaked separately in 1.8 litres of 70% aqueous ethanol, 1.8 litres of 70% aqueous methanol and 1.8 litres of distilled water for 24 hours. After 24hours, the extract was sieved with a muslin cloth and this was stored in a refrigerator when not in use.

Phytochemical Screening of the Crude Extract
The processed crude extracts were aseptically carried using Laboratory sample bottles (to avoid contamination on transit) to the National Research Institute for Chemical Technology (NARICT) Basawa, Zaria, kaduna State where laboratory tests were conducted on the crude extracts of the powdered specimens using standard procedures (Untargeted Gas Chromatography-Mass Spectrometry (GC-MS)).

GC -MS Experimental Conditions
The analysis was performed using Agilent Gas chromatography couple to the mass spectrometer system (model GC Agilent S/N 7890A and 5975A). HP 5ms 5% phenyl Methyl) siloxane Capillary Colum (30M x 250m) was used under the following conditions: Oven temperature 70 o C for 1 min, then increase to 280 o C by 10 o C/min for 10 min and Injector temperature of 260 o C. Helium gas was used as the carrier gas with flow rate of 1.9m/min, the volume of the injected sample was 1uL of diluted extract in ethanol, methanol and distilled water. Split injection techniques were used during sample injection with ionization energy 70ev in the electron ionization (EI) mode, ion source temperature 230 o C scan mass range of M/Z 50-500.

Identification of Constituents
The constituents of the plant material were identified base on the result obtained from the library search and mass spectra of most of the compound with data generated under identical experimental conditions by applying a search algorithm considering the retention index as well as mass spectra similar with those of authentic compounds available in NIST, 2011 and NIST, 2014 Library.
Result obtained from a study shows that the application of leaves and bark extracts of F. exasperata was effective in the control of insect pest infestation when compared with control (Alamu, 2018). The Leaves and stem of F. sarmentosa var. henryi have been reported to posessed insecticide activity (Wang et al., 2011). Result obtained from a study shows that the application of leaves and bark extracts of F. exasperata was effective in the control of insect pest infestation when compared with control (Alamu, 2018). Diouf et al. (2016) shown that the extracts with the cyclohexane and methanolic of Ficus thonnigii are more effective on Callosobruchus maculatus. Thus, the methanolic extract (EM) of Ficus thonningii reduces considerably the number of insects emerged in the short run on Callosobruchus maculatus.

CONCLUSION AND RECOMMENDATIONS
The present study suggest an enormous biological potential of F.poita leaves. It could be concluded that, the study have provided baseline information on several phytoconstituents found in F.poita leaves extracts and many information on Ficus spp potential and validity in the treatment and management of insect pests associated with stored grains. Further investigations on the bio insecticidal activity of these compounds and spectrum of activity of F.poita leaves against other stored products insects, as well as the optimal level of application necessary to afford complete protection of stored grain, is highly advocated.