The role of bixin as antioxidant, anti-inflammatory, anticancer, and skin protecting natural product extracted from Bixa orellana L.

Since long, medicinal plants or herbs are being used in different traditional treatment systems as therapeutic agents to treat a variety of illnesses. Bixa orellana L., an medicinal plant (family: Bixaceae), is an Ayurvedic herb used to treat dyslipidemia, diarrhoea, and hepatitis since ancient times. B. orellana L., seeds contain an orange-red coloured component known as bixin (C25H30O4), which constitutes 80% of the extract.Chemically, bixin is a natural apocarotenoid, biosynthesized through the oxidative degradation of C40 carotenoids. Bixin helps to regulate the Nrf2/MyD88/TLR4 and TGF-1/PPAR-/Smad3 pathways, which further give it antifibrosis, antioxidant, and anti-inflammatory properties. This current review article presents a comprehensive review of bixin as an anti-inflammatory, antioxidant, anticancer,and skin protecting natural product. In addition, the biosynthesis and molecular target of bixin, along with bixin extraction techniques, are also presented.

Intramuscular compatibility of an injectable anti-inflammatory nanodispersion from a standardized Bixa orellana oil (Chronic®): a toxicological study in Wistar rats.

Bixa orellana L. is a plant popularly known as "ucurum", "annatto", and "achiote". It is native to South America, and its seeds are an abundant source of geranylgeraniol and tocotrienols. Nanoencapsulation is a valuable technique that can decrease the drug needed to achieve an effect, decreasing potential toxicity, side effects and potentiate the anti-inflammatory effect. This study aimed to evaluate the acute toxicity of an intramuscular application of a nanodispersion containing a standardized extract from the seeds of Bixa orellana (NBO) in Wistar rats. The chemical evaluation showed δ-tocotrienol at 0.725 ± 0.062 mg/mL (72.6 ± 0.9%). The stability study showed the nanoparticles had an average size from 53.15 ± 0.64 to 59.9 ± 3.63 nm, with a polydispersity index ranging from 0.574 ± 0.032 to 0.574 ± 0.32, Zeta potential from 18.26 ± 0.59 to 19.66 ± 1.45 mV. After testing the intramuscular application of NBO with doses from 1 to 5 mg/kg in animals, it was observed that the acute treatment did not elicit any toxic effects within this range. The dose of 10 mg/kg, although not affecting hematological and biochemical parameters (CPK, LDH, myoglobin, AST, ALT, TC, TG, glucose levels, creatinine, and urea), could induce some muscle tissue changes, including leukocyte infiltration, morphological chances, and potentially necrosis. In conclusion, the results showed that the treatments devoided toxicity between 1 and 5 mg/kg.

Bixasteroid, a new compound from the fruits of Bixa orellana and its anti-inflammatory activity.

Bixasteroid (1), one new steroid together with five known compounds (2-6), were isolated from the ethyl acetate fraction of ethanol extract of Bixa orellana fruits. All of these known compounds were isolated from the plant for the first time. Their structures were elucidated on the basis of spectroscopic analysis, and the absolute configuration of compound 1 was determined by X-ray crystallographic data analysis as well as by the quantum chemical ECD calculations. All the isolated compounds were tested for their anti-inflammatory activities. Compounds 1 and 2 showed inhibiting NO release activities in LPS-induced RAW 264.7 macrophages with the IC50 values of 4.72 ± 0.28 and 5.48 ± 1.48 µM, respectively.

Potential of the Compounds from Bixa orellana Purified Annatto Oil and Its Granules (Chronic®) against Dyslipidemia and Inflammatory Diseases: In Silico Studies with Geranylgeraniol and Tocotrienols.

Some significant compounds present in annatto are geranylgeraniol and tocotrienols. These compounds have beneficial effects against hyperlipidemia and chronic diseases, where oxidative stress and inflammation are present, but the exact mechanism of action of such activities is still a subject of research. This study aimed to evaluate possible mechanisms of action that could be underlying the activities of these molecules. For this, in silico approaches such as ligand topology (PASS and SEA servers) and molecular docking with the software GOLD were used. Additionally, we screened some pharmacokinetic and toxicological parameters using the servers PreADMET, SwissADME, and ProTox-II. The results corroborate the antidyslipidemia and anti-inflammatory activities of geranylgeraniol and tocotrienols. Notably, some new mechanisms of action were predicted to be potentially underlying the activities of these compounds, including inhibition of squalene monooxygenase, lanosterol synthase, and phospholipase A2. These results give new insight into new mechanisms of action involved in these molecules from annatto and Chronic®.

Evaluation of a Zingiber officinale and Bixa orellana Supplement on the Gut Microbiota of Male Athletes: A Randomized Placebo-Controlled Trial.

The gut microbiota has emerged as a factor that influences exercise performance and recovery. The present study aimed to test the effect of a polyherbal supplement containing ginger and annatto called "ReWin(d)" on the gut microbiota of recreational athletes in a pilot, randomized, triple-blind, placebo-controlled trial. Thirty-four participants who practice physical activity at least three times weekly were randomly allocated to two groups, a ReWin(d) group or a maltodextrin (placebo) group. We evaluated the gut microbiota, the production of short-chain fatty acids, and the serum levels of interleukin-6 and lipopolysaccharide at baseline and after 4 weeks. Results showed that ReWin(d) supplementation slightly increased gut microbiota diversity. Pairwise analysis revealed an increase in the relative abundance of Lachnospira (ß-coefficient = 0.013; p = 0.001), Subdoligranulum (ß-coefficient = 0.016; p = 0.016), Roseburia (ß-coefficient = 0.019; p = 0.001), and Butyricicoccus (ß-coefficient = 0.005; p = 0.035) genera in the ReWin(d) group, and a decrease in Lachnoclostridium (ß-coefficient = - 0.008; p = 0.009) and the Christensenellaceae R7 group (ß-coefficient = - 0.010; p < 0.001). Moreover, the Christensenellaceae R-7 group correlated positively with serum interleukin-6 (ρ = 0.4122; p = 0.032), whereas the Lachnospira genus correlated negatively with interleukin-6 (ρ = - 0.399; p = 0.032). ReWin(d) supplementation had no effect on short-chain fatty acid production or on interleukin-6 or lipopolysaccharide levels.

Bixa orellana L. carotenoids: antiproliferative activity on human lung cancer, breast cancer, and cervical cancer cells in vitro.

Emerging evidence on the potential pro-oxidant effect of carotenoids provokes apoptosis of cancer cells. Bixa orellana L. is native to Central and South America, interestingly, is also cultivated worldwide. Apo-carotenoids present in B. orellana L. are mainly dominated by bixin and norbixin and demonstrate fundamental antioxidant activity. Anti-proliferative activity on human cancer cells is rarely investigated. We isolated bixin from B. orellana L. found in the island of Java using Ultra-Fast Liquid Chromatography and confirmed the isolated compound using Liquid Chromatography-MS/MS. Bixin and crude extract were examined on human lung cancer (A549), cervical cancer (HeLa), and breast cancer (MCF-7). Anti-proliferative activity revealed to be promising on both, the isolated pigment and crude extract. Further investigation on the mechanism of action and effect on other cell lines, both in vitro and in vivo, are required before clinical translation.

Heterologous expression of Bixa orellana cleavage dioxygenase 4-3 drives crocin but not bixin biosynthesis.

Annatto (Bixa orellana) is a perennial shrub native to the Americas, and bixin, derived from its seeds, is a methoxylated apocarotenoid used as a food and cosmetic colorant. Two previous reports claimed to have isolated the carotenoid cleavage dioxygenase (CCD) responsible for the production of the putative precursor of bixin, the C24 apocarotenal bixin dialdehyde. We re-assessed the activity of six Bixa CCDs and found that none of them produced substantial amounts of bixin dialdehyde in Escherichia coli. Unexpectedly, BoCCD4-3 cleaved different carotenoids (lycopene, ß-carotene, and zeaxanthin) to yield the C20 apocarotenal crocetin dialdehyde, the known precursor of crocins, which are glycosylated apocarotenoids accumulated in saffron stigmas. BoCCD4-3 lacks a recognizable transit peptide but localized to plastids, the main site of carotenoid accumulation in plant cells. Expression of BoCCD4-3 in Nicotiana benthamiana leaves (transient expression), tobacco (Nicotiana tabacum) leaves (chloroplast transformation, under the control of a synthetic riboswitch), and in conjunction with a saffron crocetin glycosyl transferase, in tomato (Solanum lycopersicum) fruits (nuclear transformation) led to high levels of crocin accumulation, reaching the highest levels (>100 µg/g dry weight) in tomato fruits, which also showed a crocin profile similar to that found in saffron, with highly glycosylated crocins as major compounds. Thus, while the bixin biosynthesis pathway remains unresolved, BoCCD4-3 can be used for the metabolic engineering of crocins in a wide range of different plant tissues.

Self-emulsified annatto tocotrienol improves bone histomorphometric parameters in a rat model of oestrogen deficiency through suppression of skeletal sclerostin level and RANKL/OPG ratio.

Menopause is the leading cause of osteoporosis for elderly women due to imbalanced bone remodelling in the absence of oestrogen. The ability of tocotrienol in reversing established bone loss due to oestrogen deficiency remains unclear despite the plenitude of evidence showcasing its preventive effects. This study aimed to investigate the effects of self-emulsified annatto tocotrienol (SEAT) on bone histomorphometry and remodelling in ovariectomised rats. Female Sprague Dawley rats (n=36) were randomly assigned into baseline, sham, ovariectomised (OVX) control, OVX-treated with annatto tocotrienol (AT) (60 mg/kg), SEAT (60 mg/kg) and raloxifene (1 mg/kg). Daily treatment given through oral gavage was started two months after castration. The rats were euthanised after eight weeks of treatment. Blood was collected for bone biomarkers. Femur and lumbar bones were collected for histomorphometry and remodelling markers. The results showed that AT and SEAT improved osteoblast numbers and trabecular mineralisation rate (p<0.05 vs untreated OVX). AT also decreased skeletal sclerostin expression in OVX rats (p<0.05 vs untreated OVX). Similar effects were observed in the raloxifene-treated group. Only SEAT significantly increased bone formation rate and reduced RANKL/OPG ratio (p<0.05 vs untreated OVX). However, no changes in osteoclast-related parameters were observed among the groups (p>0.05). In conclusion, SEAT exerts potential skeletal anabolic properties by increasing bone formation, suppressing sclerostin expression and reducing RANKL/OPG ratio in rats with oestrogen deficiency.

Bixin protects mice against bronchial asthma though modulating PI3K/Akt pathway.

Accumulating evidence has implicated the potential of natural compounds in treatment of asthma. Bixin is a natural food coloring isolated from the seeds of Bixa Orellana, which possesses anti-tumor, anti-inflammatory and antioxidative properties. Nevertheless, its therapeutic effect in asthma has not been elucidated. Our present study demonstrated that administration of Bixin suppressed allergic airway inflammation and reversed glucocorticoids resistance, as well as alleviated airway remodeling and airway hyperresponsiveness (AHR) in asthmatic mice. In vitro studies showed that Bixin treatment could inhibit the development of epithelial-mesenchymal transition (EMT) mediated by transforming growth factor beta (TGF-ß) signaling. Importantly, Bixin antagonized activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway both in vitro and in vivo. Above all, our findings reveal that Bixin functions as a potent antagonist of PI3K/Akt signaling to protect against allergic asthma, highlighting a novel strategy for asthma treatment based on natural products.

Co-Treatment of Purified Annatto Oil (Bixa orellana L.) and Its Granules (Chronic®) Improves the Blood Lipid Profile and Bone Protective Effects of Testosterone in the Orchiectomy-Induced Osteoporosis in Wistar Rats.

This study aimed to evaluate and compare the effects of co-treatment with purified annatto oil (PAO) or its granules (GRA, Chronic®) with that of testosterone on the orchiectomy-induced osteoporosis in Wistar rats. After surgery, rats were treated from day 7 until day 45 with testosterone only (TES, 7 mg/kg, IM) or TES + PAO or GRA (200 mg/kg, p.o.). The following parameters were evaluated: food/water intake, weight, HDL, LDL, glucose, triglycerides (TG), total cholesterol (TC), alkaline phosphatase levels, blood phosphorus and calcium contents, femur weight, structure (through scanning electron microscopy), and calcium content (through atomic absorption spectrophotometry). Our results show that orchiectomy could significantly change the blood lipid profile and decrease bone integrity parameters. Testosterone reposition alone could improve some endpoints, including LDL, TC, bone weight, and bone calcium concentration. However, other parameters were not significantly improved. Co-treatment with PAO or GRA improved the blood lipid profile and bone integrity more significantly and improved some endpoints not affected by testosterone reposition alone (such as TG levels and trabeculae sizes). The results suggest that co-treatment with annatto products improved the blood lipid profile and the anti-osteoporosis effects of testosterone. Overall, GRA had better results than PAO.

Therapeutic potential of annatto tocotrienol with self-emulsifying drug delivery system in a rat model of postmenopausal bone loss.

Tocotrienol has been shown to prevent bone loss in animal models of postmenopausal osteoporosis, but the low oral bioavailability might limit its use. A self-emulsifying drug delivery system (SEDDS) could increase the bioavailability of tocotrienol. However, evidence of this system in improving the skeletal effects of tocotrienol is scanty. This study aims to evaluate the therapeutic efficacy of annatto tocotrienol with SEDDS in a rat model of postmenopausal bone loss. Ten-month-old female Sprague Dawley rats were randomized into six groups. The baseline group was euthanatized at the onset of the study. Four other groups underwent ovariectomy to induce estrogen deficiency. The sham underwent similar surgery procedure, but their ovaries were retained. Eight weeks after surgery, the ovariectomized rats received one of the four different regimens orally daily: (a) SEDDS, (b) annatto tocotrienol [60 mg/kg body weight (b.w.)] without SEDDS, (c) annatto-tocotrienol (60 mg/kg b.w.) with SEDDS, (d) raloxifene (1 mg/kg b.w.). After eight weeks of treatment, blood was collected for the measurement of delta-tocotrienol level and oxidative stress markers. The rats were euthanized and their bones were harvested for the evaluation of the bone microstructure, calcium content and strength. Circulating delta-tocotrienol level was significantly higher in rats receiving annatto tocotrienol with SEDDS compared to the group receiving unformulated annatto-tocotrienol (p < 0.05). Treatment with unformulated or SEDDS-formulated annatto tocotrienol improved cortical bone thickness, preserved bone calcium content, increased bone biomechanical strength and increased antioxidant enzyme activities compared with the ovariectomized group (p < 0.05). Only SEDDS-formulated annatto tocotrienol improved trabecular microstructure, bone stiffness and lowered malondialdehyde level (p < 0.05 vs the ovariectomized group). The improvement caused by annatto tocotrienol was comparable to raloxifene. In conclusion, SEDDS improves the bioavailability and skeletal therapeutic effects of annatto tocotrienol in a rat model of postmenopausal bone loss. This formulation should be tested in a human clinical trial to validate its efficacy.

Modified-release of encapsulated bioactive compounds from annatto seeds produced by optimized ionic gelation techniques.

To compare the encapsulation of annatto extract by external gelation (EG) and internal gelation (IG) and to maximize process yield (% Y), two central composite designs were proposed. Calcium chloride (CaCl2) concentration (0.3-3.5%), alginate to gelling solution ratio (1:2-1:6); acetic acid (CH3COOH) concentration (0.2-5.0%) and alginate to gelling solution ratio (1:2-1:6) were taken as independent variables for EG and IG respectively. Release studies were conducted under different conditions; morphology, particle size, the encapsulation efficiency (EE), and release mechanism were evaluated under optimized conditions. The optimized EG conditions were 0.3% CaCl2 and 1:1.2 alginate to gelling solution ratio, whereas a 0.3% CH3COOH and 1:5 alginate to gelling solution ratio were optimized conditions for IG. When 20% extract was employed, the highest EE was achieved, and the largest release was obtained at a pH 6.5 buffer. The Peppas-Sahlin model presented the best fit to experimental data. Polyphenol release was driven by diffusion, whereas bixin showed anomalous release. These results are promising for application as modulated release agents in food matrices.

Bixa orellana L. by-products' fractions from an industrial process: antiproliferative activity on tumor cells and chemical profile.

This study evaluated the phytochemical characterization of Bixa orellana (BO extract) unsaponifiable extract and resulting fractions (F fraction - FF, Geranyl fraction - GF and R fraction- RF) obtained as by-products of an industrial process investigating in vitro antiproliferative activities in human tumoral cells. The main compounds identified by GC-MS for BO extract were Geranylgeraniol (61.51%); for FF: Geranylgeraniol (70.23%); for GF: Geranylgeraniol (78.92%) and for RF: ß-cubebene (27.75%). Quantifications of geranylgeraniol by GC-FID presented the percentage content: BO 27.52%; FF 38.52%; GF 51.44% and RF 1.81%. BO extract showed a significant antiproliferative activity, with GI50 up to 4 µg/mL. All fractions had a remarkably similar antiproliferative activity profile (GI50 27-47 µg/mL). Data reported herein showed an important cytostatic effect for BO extract, nevertheless this activity is not attributed exclusively to geranylgeraniol. In conclusion, this by-product becomes of great value, being a potential candidate for development of new anti-tumor ingredients.

Inoculation of arbuscular mycorrhizal fungi as a strategy to improve annatto (Bixa orellana L. ) growth

This study aimed to assess the occurrence of arbuscular mycorrhizal fungi (AMF) in annatto (Bixa orellana L.) cultivars and their response to AMF inoculation using biometric parameters. The occurrence surveys were conducted in annatto fields in three municipalities from Pernambuco Forest Zone: Lagoa de Itaenga, Gloria de Goitá, and Vitoria de Santo Antão, and in four cultivars (Red Piave, Green Piave, Red Peruvian Paulista, and Green Peruvian Paulista). In a greenhouse, biometric parameters of annatto seedlings of Red Piave, Red Peruvian Paulista, Embrapa-36, and Embrapa-37 cultivars inoculated with AMF isolated from annatto fields. The Red Piave cultivar exhibited greater root colonization than the Green Peruvian Paulista in the Lagoa de Itaenga and Vitoria de Santo Antão municipalities. The cultivar Red Piave showed a more beneficial association with AMF in plants and soil than cultivar Green Peruvian Paulista did, in both Lagoa de Itaenga and Vitoria de Santo Antão. AMF inoculation was effective in promoting the growth of annatto plants, particularly those inoculants with S. heterogama and C. etunicatum.

Osteoprotective effect of green tea polyphenols and annatto-extracted tocotrienol in obese mice is associated with enhanced microbiome vitamin K2 biosynthetic pathways.

The role of the gut microbiome in bone health has received significant attention in the past decade. We investigated the effects of green tea polyphenols (GTP) and annatto-extracted tocotrienols (AT) on bone properties and gut microbiome in obese mice. Male mice were assigned to a two (no AT vs. 400 mg/kg diet AT) × two (no GTP vs. 0.5% w/v GTP) factorial design, namely control, G, T, and G+T group respectively, for 14 weeks. The 4th lumbar vertebra (LV-4) and femur were harvested for bone microstructural analysis using µ-CT. Microbiome analysis using 16S rRNA gene sequencing of cecal feces was performed. AT increased bone volume at distal femur. GTP increased serum procollagen type 1 N-terminal propeptide concentration, bone volume at the distal femur and the LV-4, and trabecular number at distal femur; whereas GTP decreased trabecular separation at distal femur. Interactions between GTP and AT were observed in serum C-terminal telopeptide of type I collagen level (control>G=T=G+T) as well as the cortical bone area (control

Dietary supplementation with annatto food-coloring extracts increases the resistance of human erythrocytes to hemolysis.

Erythrocytes exhibit high susceptibility to hemolysis in several pathologies due to the oxidation of cellular components. We hypothesized that annatto carotenoids improve the redox status of erythrocyte plasma membranes and promote a consequent increase in human erythrocyte resistance to hemolysis. The objective of this study was to evaluate whether food-grade annatto carotenoids can increase human erythrocyte resistance to hemolysis in vitro and ex vivo. For the in vitro experiment, erythrocytes from healthy volunteers were isolated and coincubated with bixin (BIX) or norbixin (NBIX) and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), glucose, or sodium nitrite (NaNO2) as hemolysis inducers. In the ex vivo study, healthy volunteers consumed a capsule containing BIX or NBIX (0.05 mg/kg body weight per day) or placebo for 7 days before blood sample collection. Their erythrocytes were isolated and incubated with AAPH, glucose, or NaNO2. In both the ex vivo and in vitro studies, erythrocytes were subjected to osmotic fragility tests. The activity of antioxidant enzymes, and reduced glutathione and lipid peroxidation levels in erythrocytes were also evaluated ex vivo. In vitro BIX and NBIX not only reduced erythrocyte membrane fragility induced by AAPH, glucose, or NaNO2 but also improved basal osmotic resistance in the micromole-per-liter range (P < .05). BIX and NBIX supplementation increased erythrocyte membrane resistance (P < .05), with BIX being more effective. Also, BIX and NBIX protected erythrocytes from lipid peroxidation and improved the cellular redox environment (P < .05). These results support the hypothesis that annatto carotenoids supplementation exerts antihemolytic properties by preventing the oxidative damage of human erythrocytes.

Synthesis and characterisation of novel biopolymer stabilised organic Pt-nanocomposite: assessment of its antioxidant and antitumour properties.

Green synthesis of organic Pt-nanocomposite was accomplished using carboplatin as a precursor and novel biopolymer - gum kondagogu (GK) as a reducing agent. The synthesised GK stabilised organic Pt-nanocomposite (GKCPt NC) was characterised by different analytical techniques such as ultraviolet-visible spectroscopy, nanoparticle analyser, scanning electron microscopy and energy dispersive X-ray analysis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrophotometer. The XRD pattern established the amorphous nature of GKCPt NC. TEM analysis revealed the homogeneous, monodisperse and spherical nature, with Pt metal size of 3.08 ± 0.62 nm. The binding energy at 71.2 and 74.6 eV show the presence of metallic platinum, Pt(0) confirmed by XPS studies. Further, in vitro radical scavenging and antitumour activity of GKCPt NC have been investigated. In comparison to GK and carboplatin, GKCPt NC showed superior 1, 1-diphenyl-2-picrylhydrazyle activity of 87.82%, whereas 2, 2-azinobis-(3-ethylbenzthinzoline-6-sulphonic acid) activity was 38.50%, respectively. In vitro studies of the antitumour property of GK, GKCPt NC and carboplatin were evaluated by potato disc tumour bioassay model. The efficacy of synthesised GKCPt NC concentration (IC50) on tumour inhibition was found to be 2.04-fold lower as compared to carboplatin. Overall, the synthesised GKCPt NC shows both antitumour and antioxidant properties when compared to the original drug - carboplatin and might have promising applications in cancer therapy.

The effects of photodynamic therapy with blue light and papain-based gel associated with Urucum, on collagen and fibroblasts: a spectroscopic and cytotoxicity analysis.

Papacarie Duo™ is clinically used and has proven effectiveness; however, it is necessary to improve its antimicrobial action. The combined treatment of Papacarie Duo™ with Urucum (Bixa Orellana) could create a potential tool for dental caries treatment; its extract obtained from the seeds' pericarp contains a water-soluble primary pigment (cis-bixin) with smaller amounts of other carotenoids. The dicarboxylic acid salts of cis-norbixin and trans-norbixin occur in heated alkaline solutions. To analyze the absorption spectra and cytotoxicity (with human dermal fibroblasts) in different concentrations of Urucum, associated or not with Papacarie Duo™, we performed this in vitro study. The effects of pure Urucum, Papacarie Duo™, and PapaUrucum™ on the microstructure of collagen were also analyzed. The application of papain-based gel with Urucum did not present cytotoxicity, its exhibit UV absorption spectrum peak around 460 ± 20 nm. Also, it showed that the compound used did not alter the chemical structure of collagen. Consequently, this product could be used as a chemomechanical method to remove dentin caries as well as being a potential product for antimicrobial photodynamic therapy (aPDT) application.

Tocotrienol-rich fraction from annatto ameliorates expression of lysyl oxidase in human osteoblastic MG-63 cells.

Lysyl oxidase (LOX) is required for the formation of bone collagen cross-links. Inactivation of the LOX gene in osteoblasts by DNA methylation and JAK signaling has been reported to cause loss of cross-links and an increased risk of fractures. Tocotrienols (T3s) have proven benefits on bone strength, but their potential effects on LOX remain largely unknown. Thus, the present study investigates the in vitro effects of T3s on LOX expression in human osteoblastic MG-63 cells. Results indicated that Tocotrienol-Rich Fraction (TRF), the δ-T3 rich oil extracted from Annatto was the most effective and significantly increased LOX expression. TRF treatment decreased de-novo methyltransferases (DNMTs), DNMT3A and DNMT3B levels. In addition, TRF significantly inhibited JAK2 activation and decreased expression of Fli1, a transcription factor of DNMTs. We conclude that TRF induced an increase in LOX expression via inhibition of de-novo methylation and reduction of Fli1 expression by the inactivation of JAK2.Abbreviations: CpG: cytosine-guanine dinucleotide; DNMT: DNA methyltransferase; Fli1: friend leukemia virus integration 1; JAK: janus kinase; LOX: lysyl oxidase; PCR: polymerase chain reaction; STAT: signal transducers and activators of transcription; T3s: tocotrienols; TPs: tocopherols; TRF: Tocotrienol-Rich Fraction.

The Effects of Tocotrienol on Bone Peptides in a Rat Model of Osteoporosis Induced by Metabolic Syndrome: The Possible Communication between Bone Cells.

A positive association between metabolic syndrome (MetS) and osteoporosis has been demonstrated in previous animal studies. The mechanisms of MetS in orchestrating the bone remodelling process have traditionally focused on the interactions between mature osteoblasts and osteoclasts, while the role of osteocytes is unexplored. Our earlier studies demonstrated the bone-promoting effects of tocotrienol using a rat model of osteoporosis induced by MetS. This study aimed to investigate the expression of osteocyte-derived peptides in the bone of rats with MetS-induced osteoporosis treated with tocotrienol. Age-matched male Wistar rats (12-week-old; n = 42) were divided into seven experimental groups. Two groups served as the baseline and normal group, respectively. The other five groups were fed with a high-carbohydrate high-fat (HCHF) diet to induce MetS. The five groups of HCHF animals were treated with tocopherol-stripped corn oil (vehicle), annatto tocotrienol (60 and 100 mg/kg), and palm tocotrienol (60 and 100 mg/kg) starting from week 8. At the end of the study, the rats were sacrificed and their right tibias were harvested. Protein was extracted from the metaphyseal region of the proximal right tibia and levels of bone peptides, including osteoprotegerin (OPG), soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), sclerostin (SOST), Dickkopf-related protein 1 (DKK-1), fibroblast growth factor-23 (FGF-23), and parathyroid hormone (PTH), were measured. The vehicle-treated animals displayed higher levels of sRANKL, SOST, DKK-1, FGF-23, and PTH as compared to the normal animals. Oral supplementation of annatto and palm tocotrienol (60 and 100 mg/kg) reduced the levels of sRANKL and FGF-23 in the HCHF animals. Only 100 mg/kg annatto and palm tocotrienol lowered SOST and DKK-1 levels in the HCHF animals. In conclusion, tocotrienol exerts potential skeletal-promoting benefit by modulating the levels of osteocytes-derived bone-related peptides.