Samples Collection and Extraction
Ficus deltoidea (female leaves) and Gynochthodes sublanceolata were collected from the covered green house garden of School of Bioprocess Engineering and University Malaysia Perlis. Then, they were cleaned with a running tap water to remove debris and contamination. Each set of the collection was dried at room temperature for two weeks. The dried leaves were ground, then 100 grams (50 grams from each plant leaves) were mixed grams were mixed with 2000 ml of a methanol: distilled water (60:40 % v/v) was put in a beaker and covered with aluminum foil at an ambient temperature about 24 h and shaken during the extraction. The extract was filtered through Whatman No.1 filter paper. Then, the solvent was removed from samples using a rotary evaporator then freeze dryer was used to transform the sample into the powder form. Finally, the extract was placed in air-tight amber bottles and stored in a freezer to prevent the oxidation of damage until further use (Kavitha et al., 2017).
Hydroxyapatite (HAp) Preparation by direct precipitation
In this experiment, HAp was obtained by a direct precipitation. According to Song et al. the Stoichiometric reaction of calcium nitrate tetrahydrate (Ca(NO3)2. 4H2O and ammonium phosphate (NH4H2PO4) will yield the hydroxyapatite as below;
5Ca (NO3) + 3(NH4)2 HPO4+ H2O ? Ca5 (PO4)3OH+ 6NH4NO3+ 4HNO3
Calcium nitrate tetrahydrate (Ca(NO3)24H2O and ammonium phosphate (NH4H2PO4) were dissolved in 100 ml distilled water at room temperature. In this experiment, calcium nitrate tetrahydrate act as a calcium source, while ammonium dihydrogen phosphate acts as a phosphorus source. The concentration 100 mM of (Ca(NO3)24H2O and 60 mM of (NH4H2PO4) was applied to give the molar ratio of calcium to phosphate is 1.67. The solution then was poured and mix into a set up magnetic stirrer beaker on the hot plate at 60 °C while the stirring rate at 550 rpm the mixing was conducted for 1 hour. After that, the suspension will be filtered by using Whatman filter No.1 paper, the drying process was carried out in an oven at a temperature of 60 °C for 24 hours. Finally, the dried sample was crushed by using pestle and mortar for 5 minutes.
Preparation of Encapsulated Phyto-extract Nano-hybrid with Hap
Nanoparticles containing the phyto-components combination from the test plants were prepared by solvent evaporation method described before with the additional modifications (Bernard, S. A., &Olayinka, 2010. Accurately weighed amount of HAp and plant extract with mass ratio were chosen, which includes 1:5. They were separately dissolved in distilled water containing ethanol for plant extract and ethanol for HAp, then mixed and stirred for 2 hr to evaporate the organic solvent and left for 24 hr at room temperature. The nanoparticles formed were isolated by centrifugation for 15 minutes at 10000 xg. Finally, the nanoparticles were washed with deionized water to remove the residual solvent.
Test animal
The animal study was approved and conducted in strict guidance according to Eman Research Animal Ethics Committee Malaysia (Reference #: 112074A2212130719. Healthy BALB/c mice in a weight of 20–30 g were kept in an animal house in EMAN Biodiscoveries, Malaysia. Plastic cages (34 × 47 × 18 cm3) at animal house are used to keep animals. There were five mice in each cage which is in an air conditioned environment at room temperature of (25 ± 2)°C with relative humidity (60% ± 10%) under 12 h night and light cycle. The animals were fed with commercially available standard pellet chow and unlimited supply of filtered drinking water.
Acute toxicity study
The oral acute toxicity study of encapsulated extract was evaluated according to Organization for Economic Cooperation and Development (OECD) guideline 423 on BALB/c mice (20–30 g) (Walum, 1998), where the test doses of 300, 2000 and 4000 mg/kg were used. Before the experiment was done all the animals free excess to water, andwere kept at overnight fasting. The mice were divided into four groups of five animals for each group each (n=5). The 1st group belongs to the control, whereas the 2nd, 3rd and 4th groups are experimental groups that received orally encapsulated extract (in normal saline) at dose of 300 mg/kg, 2000 mg/kg and 4000 mg/kg respectively. Before dose administration, the body of each animal was weighed, and there was a calculation of the dose based on the body weight An animal was not observed any toxic effect for the first 4 hour after a period of treatment More animals were observed and investigated within 3 days for if any toxic effect. It was found that there were behavioral changes and other parameters such as body weight, urinations, food intake, water intake, respiration, convulsion, tremor, temperature, constipations. Also, their eye and skin colors changed etc (Yehya et al., 2019).
Sub-chronic toxicity study
According to OECD guideline 407 (Gopinath et al., 2016), oral sub-chronic toxicity study was conducted. Fifteen healthy BALB/c mice (20–30 g) were divided into three groups five animal each and kept under standard conditions. The control group belongs to Group I; whereas the experimental groups are the other two groups which received the encapsulated extract at a dose of 600 and 1000 mg/kg, respectively within 28 consecutive days (Anniebell, and Gopinath, 2018). The control group was received normal saline. The second and third groups were given with a single dose of 600 mg/kg and 1000 mg/kg of body weight of encapsulated extract, respectively. Gavage dosing was performed using a curved, ball-tipped intubation needle affixed to a 5 ml syringe. Fresh preparation of solutions was made prior to dosing and they were kept chilled and tightly capped.
Hematological and biochemical examination
At the end of study, animals should be anaesthetized with a ketamine and xylazine with 0.05-0.1mL/10g body weight . 1mL of ketamine (100mg/mL) and 0.5mL xylazine (20mg/mL) single dose. after anovernight fasting (8 h). Test tube contains blood sample with and ethylene diaminetetra acetic acid as an anticoagulant, and without it respectively for biochemical and hematological parameters. Biochemical analysis was done through the evaluation of blood without the ethylene diamine tetra acetic acid, allowed to clot after centrifugation at 2 500 r/min for 15 min to obtain serum and stored at -20°C until it was assayed for biochemical estimation. After blood was collected, all important organ, namely liver, kidney, lung, heart, pancreas and small intestine were harvested. Each organ was weighed on electronic balance to observe any changes in organs weights of treated animals compared to control group )( Suk et al., 2018). The relative organ weight (ROW) of each organ was calculated as follows (Anniebell, and Gopinath, 2018):
ROW= (Absolute organ weight (g) / mice body weight on sacrifice day) ×100
Effect of encapsulate plant extract on hematological parameters
Red blood cell count, hematocrit, mean cell volume, hemoglobin, white blood cell count, mean corpuscular hemoglobin concentration, mean corpuscular volume, monocyte, neutrophil, lymphocyte and platelet count of the control and treated groups were determined and compared with control group using an automatic hematology analyzer (Sysmex K21, Tokyo, Japan).
Effect of encapsulate plant extract on serum biochemical parameters
There was an biochemical analysis on serum after collected blood was centrifugated, and the following parameters such as aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase, high density lipoprotein, total bilirubin (TBIL), total protein, albumin, urea and creatinine level were determined for both control and extract treated groups. All analyses were done through the analyzer of clinical chemistry.
Histopathological studies
After the experimental stage, the animals were sacrificed and necropsied. Different visceral organs including kidney, liver and lung were collected and fixed in 10% formaldehyde solution. The tissues were further processed with the Automatic Tissue Processor and sectioned at 5 µm thickness using the Rotary Microtome (Heitz 150 Rotary Microtome, Cambridge model) and embedded in paraffin wax to prepare blocks. Sections were stained according to Haematoxylin and Eosin (H and E) technique for microscopically examination (Suk et al., 2017). Subsequently, the sections were examined using Swift Binocular Microscope with in-built lighting system and photographed using a microscope-digital-camera with an Olympus photomicroscope.
Statistical analysis
Statistical analysis was done as mean of variance ± SEM (n = 5), followed by ANOVA test using Graph Pad Prism and for multiple comparison test among the groups, Bonferroni test was performed. A probability level 0of p < 0.001 was accepted statistically (Cao et al. 2014).