Assay of the extract was 61% edible fatty acids, 26% phytocannabinoids and 13% other plant chemicals including fatty alkanes, plant sterols, triterpenes, and tocopherols. In the 14-day repeated oral dose-range finding study reported by Marx et al., a No Observed Adverse Effect Level could not be determined, however, the results of a 90-day repeated dose study with a 28-day recovery period in Wistar rats was also reported. In this study, doses of 0 , 100, 360 and 720 mg extract/kg bw per day were used. Significant decreases in body weight, body weight gain, and differences in various organ weights, compared to controls, were reported at the mid and high dose levels, but the authors concluded that many of the findings were reversible as they were trending towards normal at the end of the recovery period. A NOAEL for the hemp extract in Wistar rats in the 90-day study was determined to be 100 mg/ kg bw per day and 360 mg/kg bw per day for males and females, respectively. In the 90-day study being reported here, test article related significant changes in body weights, daily body weight gain and feed efficiency were seen in the males in all treatment groups which was still noted at the end of the recovery period. The magnitude of the significant change in body weights, daily body weight gain and feed efficiency in the low and mid dose groups was less than 10% and showed signs of obvious recovery and were therefore considered to be not toxicologically relevant. The effect in the males receiving 800 mg/kg/day was >10% and was still evident at the end of the recovery period and was considered toxicologically relevant. Reported rodent studies have differing findings on hepatotoxicity when CBD is orally administered in high doses. Hepatocellular hypertrophy with a centrilobular pattern was observed in rat livers in the study being reported.
This pattern of hepatocellular hyperplasia is frequently observed in rats and other animals exposed to agents that induce the CYP family of enzymes and can be associated with activation of peroxisome proliferator-activated receptors. THC has affinity for PPARα,trimming tray and CBD has very low to no affinity for PPARα and high affinity for PPARγ. Interaction with the PPARγ is one of the mechanisms of action for CBD. In our study, we did not show the mechanism of action for the hepatocellular hypertrophy. We did show that the activities of liver enzymes in serum were not significantly changed by treatment with the test article and the hepatocellular hypertrophy was reversed during the 28-day recovery period. In the study reported by Marx et al., no histopathological changes were observed in the livers from the treated and control rats and the liver weights in the male and female rats in the 360 and 720 mg/kg body weight/day were significantly increased at 90 days. The 28-day recovery males and females receiving 720 mg/kg/day retained the significantly increased in hepatic weights. The induction of hepatic drug metabolizing enzymes can be associated with increased liver weights, and hepatocellular hypertrophy and hyperplasia and elevation of hepatic-source enzymes in serum. The evidence in the scientific literature supports a conclusion that the centrilobular pattern of hepatocellular hypertrophy and increased liver weights observed in our study was due to induction of HDMEs and/or peroxisomes. No hepatocellular necrosis and changes in the clinical chemistries occurred which is evidence that liver damage did not occur. This conclusion is further supported by not observing hepatocellular hypertrophy and increased liver weights in the 28-day recovery groups that received the test article.In the study being reported both the treated and control male rats had the same incidence and severity of vacuolization of the adrenal zona fasciculata and the adrenal weights were significantly increased in the Group 4 females. The vacuolization of the adrenal zona fasciculata and increased adrenal weights were not observed in Groups 5 to 8. The histopathological lesions noted in the adrenal glands in the current study was seen in both control and high dose males and is not considered to be due to treatment with test article and not toxicologically relevant. The hemp extract in these studies was shown to be non-mutagenic in a bacterial test system used to evaluate mutagenicity. Marx et al. reported on a GLP-compliant study that concentrations of 5, 000 μg/plate of a CO2 supercritical extract of C. sativa were not mutagenic in a bacterial test system. Our GLP-compliant mutagenicity testing on the diluted extract showed that concentrations of 76,355 μg/plate were not mutagenic with and without the S9 metabolic activation. The extracts produced by isopropanol extraction and supercritical CO2 extraction were not mutagenic with and without S9 metabolic activation at concentrations up to 5000 μg/plate. The bacterial test system with the S9 mix did cause mutagenicity providing evidence that mutagenic metabolites were not produced with any of the extracts. The two additional Ames tests conducted on the undiluted extracts produced by two different extraction methods, were conducted to determine if the method of production or the olive oil diluent impacted the results of the Ames assay. No mutagenicity was noted in any of the tests conducted. Other botanical extracts have been evaluated for mutagenicity. Mutagenic studies on extracts from the plant Euphorbia triaculeata showed that it is not mutagenic and provides protection from the mutagenic effects of cyclophosphamide.A study on a novel taste modulating powder derived from Cordyceps sinensis showed this product was not mutagenic in the Ames test and these results were supported in the micronucleus assay. In a study on the genotoxicity of CBD in Caco-2 cells, 10 μM of CBD did not significantly cause DNA damage after 24 hours of incubation, and CBD was also shown in the comet assay to protect Caco-2 cells from hydrogen peroxide-induced DNA damage. CBD at an oral dose of 1 mg/kg was shown to significantly reduce azoxymethane-induced colonic aberrant crypt foci, colonic polyps and tumors. In summary, the test article, both undiluted and diluted in olive oil, was not mutagenic in a bacterial reverse mutation assay and the NOAEL in the 90-day study was concluded to be 800 mg/kg bw/day and 400 mg/kg bw/day for female and male Sprague Dawley rats, respectively. This assessment adds significant data to the currently available literature as to the safety and toxicology of CBD rich hemp extracts. Given the potential of CBD for a variety of human uses and the limited data currently available, these results support that hemp extracts are likely safe human consumption and additional studies should be conducted to validate this conclusion. Natural lignocellulosic fibers are in past decades gaining increased attention as sustainable materials for polymer composite reinforcement in substitution of energy intensive and non-recyclable synthetic fibers. Indeed, NLF reinforced composites are being considered for applications in civil construction, food packing, automotive components and ballistic armor. It is worth mentioning that nanocellulose fibrils obtained from NLFs are being investigated as possible reinforcement for novel bio-nanocomposites with special properties for medical applications as well as production of biodegradable plastic films. A well known NLF, the hemp fiber, has been for decades extensively reported as reinforcement of polymer composites in numerous articles and mentioned in most review papers. In fact, hemp fiber/polypropylene has been used as automotive parts. The remarkable mechanical properties of the hemp fiber, tensile strength of 900 MPa and modulus of 70 GPa, offer a possibility of use in ballistic armor reinforcing stronger thermoset polymeric matrices such as epoxy and polyester. This ballistic application has not yet been investigated in hemp fiber composites. Therefore, the objective of the present work is, for the first time, to compare the mechanical properties, evaluated by bend and tensile tests, of both epoxy and polyester composites reinforced with different amounts of hemp fibers. This would allow a definition, in terms of matrix and incorporated volume fraction, of the most suitable composite for application in multilayered armor system.The hemp fibers, Cannabis sativa, investigated in this work were supplied by Designan Fibras Naturais, Brazil, as a bundle illustrated in Fig. 1. Fibers were separated, washed in running water and dried at room temperature for one week. Characterization of the hemp fibers was conducted prior to their processing in composites. One hundred fibers were randomly pick up and measured in a profile projector Nikkon, Japan, to determine the equivalent mean diameter. The average density was obtained by the mass, in a 0.001 g precision scale, divided by the volume considering cylindrical fiber. Both epoxy and polyester resins were purchased from Resinpoxy, Brazil. The epoxy was a diglycidyl ether of the bisphenol A hardened with stoichiometric phr 13 of triethylene tetramine as the catalyst. The polyester was an unsaturated ortoftalic resin hardened with 2 wt% of methyl ethyl ketone for the curing process.Fabrication of the composites for mechanical tests was carried out by laying up continuous and aligned hemp fibers inside a steel mold, Fig. 2, trim tray pollen with internal volume of 150 × 120 × 7mm. Fibers were first cut and weighed according to the volume fraction, calculated by considering their previously evaluated density as well as the densities of epoxy and polyester from. Just before processing, the fibers were dried in a stove at 60 ◦C for 3h. Layers of fibers were placed inside the mold together with either epoxy or polyester resin, already mixed with corresponding hardener. After closing the mold, a pressure of 1 ton was applied and left to cure for 24h at RT. The produced composite plate, Fig. 2, was machined into 150 × 10 × 7mm prismatic specimens for 3 points bend tests as per ASTM D790 standard. Flat tensile specimens were directly fabricated in a specially designed steel mold, Fig. 3, in which hemp fibers were aligned together with the chosen resin already mixed with corresponding hardener. Shape of specimens with 7 × 7mm of gage cross section and 20mm of gage length as per ASTM D 638 standard. A pressure of approximately 1 MPa was applied to the mold’s lid during the cure at RT for 24h. Both flexural and tensile tests were carried out in a model 5582 Instron machine, USA, operating at RT and a crosshead speed of 0.5mm/min. Fracture analysis of ruptured specimens was performed by scanning electron microscopy in a model SSX-550 Shimadzu microscope, Japan, operating with secondary electron at 20 kV. Fourier transform infrared analysis was performed to detect functional groups in the hemp fibers as well as the effect caused by addition of these fibers in the epoxy functional group. Band spectra were obtained in a model IR-Prestige- 21 Shimadzu spectrometer, Japan, using 2mg pressed ground samples mixed with 110mg of KBr.Frequency histogram for the equivalent diameter of the as-received hemp fibers is shown in Fig. 4. The average length is 76.6mm, while the average diameter, Fig. 4, was found as 65 m. The density of the fibers was obtained as 1.35 ± 0.27 g/cm3 with thinner fibers presenting comparatively higher densities. Fig. 5 shows FTIR spectra of the hemp fiber and three hemp fiber/epoxy composites. The hemp fiber spectrum in Fig. 5 displays intense broad bands centered at 3333 and 2916 cm−1 that could be associated with O H and C–H groups in the fiber cellulose. The sharp band at 1738 cm−1 might be assigned to the C O stretching of carboxylic group of hemicellulose, while the band at 1656 cm−1 was indicated as C C as stretching of unsaturated acids or sterols in tannin. The band at 1510 cm−1 was associated with the aromatic skeletal vibration of lignin. Bands at 1425 and 1377 cm−1 and around were attributed to C–H bending as well as C–H2 rocking vibration of Fig. 4 – Histogram for equivalent diameter of the as-received hemp fibers. groups in lignin and cellulose. The 1160 and 1030 cm−1 bands were assigned to cellulose, respectively, C–O C asymmetric valence vibration and C–O stretching primary alcohol. Finally, the band at 897 cm−1 corresponds to C–H rocking vibrations of cellulose. The FTIR spectra of the hemp fibers/epoxy composites in Fig. 5 revealed bands corresponding to the plain DGEBA/TETA epoxy such as: 2963 and 2866 cm−1 assigned to C–H alkyl group; 1612 and 1510 cm−1 assigned to C C phenyl ring; 1456 and 1257 cm−1 assigned to H C–H groups; 1255 and 1030 cm−1 assigned to C–O C ether; and a small 915 cm−1 band assigned to vibration of epoxide group.