Cytotoxicity Activity of Graviola Fruit Extract with Carbamazepine and Valproic Acid Show Antagonistic and Indifferent Effects.

OBJECTIVE: Graviola is a tropical fruit with medicinal properties, used for treating various diseases such as inflammation, diabetes, and cancer. Histone deacetylase inhibitors (HDACIs), including carbamazepine (CBZ) and valproic acid (VPA), have been proven strong inhibitors against cancer cell growth. This study investigated the effect of Graviola fruit extract (GFE) on CBZ in healthy rat plasma using high-performance liquid chromatography (HPLC). In addition, the effect of GFE in combination with CBZ and VPA on two human cancer cell lines (PC3 and MCF-7) was explored. METHODS: The CBZ levels were analyzed using a simple validated HPLC method. The linearity was achieved at a 0.9998 coefficient of determination over a range of 75-5000 ng/mL CBZ. The MTT assay was used to quantify the percentage of viable cells. RESULT: The maximum plasma concentration (Cmax) and area under the curve (AUC) for CBZ alone were 4,631 ng/mL and 49,225 ng. h/mL, respectively. However, in the presence of GFE, the values reduced significantly to 2,994 ng/mL and 26,587 ng. h/mL, while the p-value was <0.05. The 3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay results for VPA showed a weak cytotoxicity activity on PC3 and MCF-7 cell lines. CONCLUSION: A simple and validated HPLC method was used to determine CBZ levels in rats' plasma. The plasma CBZ levels (Cmax) were significantly reduced in the presence of GFE, indicating the importance of drug-herb interactions. For in vitro studies, two human cancer cell lines, MCF-7 (breast cancer cells) and PC3 (prostate cancer cells), were used to screen the cytotoxicity activity of GFE, CBZ, and VPA. We observed an antagonism effect for GFE and CBZ combination in both cell lines with FIC values > 4. On the contrary, the combination of GFE and VPA showed an additive or indifferent effect.

Impact of Pomegranate Juice on the Pharmacokinetics of CYP3A4- and CYP2C9-Mediated Drugs Metabolism: A Preclinical and Clinical Review.

The Punica granatum L. (pomegranate) fruit juice contains large amounts of polyphenols, mainly tannins such as ellagitannin, punicalagin, and punicalin, and flavonoids such as anthocyanins, flavan-3-ols, and flavonols. These constituents have high antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, and anticancer activities. Because of these activities, many patients may consume pomegranate juice (PJ) with or without their doctor's knowledge. This may raise any significant medication errors or benefits because of food-drug interactions that modulate the drug's pharmacokinetics or pharmacodynamics. It has been shown that some drugs exhibited no interaction with pomegranate, such as theophylline. On the other hand, observational studies reported that PJ prolonged the pharmacodynamics of warfarin and sildenafil. Furthermore, since it has been shown that pomegranate constituents inhibit cytochrome P450 (CYP450) activities such as CYP3A4 and CYP2C9, PJ may affect intestinal and liver metabolism of CYP3A4 and CYP2C9-mediated drugs. This review summarizes the preclinical and clinical studies that investigated the impact of oral PJ administration on the pharmacokinetics of drugs that are metabolized by CYP3A4 and CYP2C9. Thus, it will serve as a future road map for researchers and policymakers in the fields of drug-herb, drug-food and drug-beverage interactions. Preclinical studies revealed that prolonged administration of PJ increased the absorption, and therefore the bioavailability, of buspirone, nitrendipine, metronidazole, saquinavir, and sildenafil via reducing the intestinal CYP3A4 and CYP2C9. On the other hand, clinical studies are limited to a single dose of PJ administration that needs to be protocoled with prolonged administration to observe a significant interaction.

The Prevalence of Overweight and Obesity Among Women in Jordan: A Risk Factor for Developing Chronic Diseases.

OBJECTIVE: The study aimed to investigate the prevalence of obesity among Jordanian women and its association with a wide range of chronic diseases. METHODS: Subjects were enrolled in the present cross-sectional study based on a random drop-off technique at the Obstetrics and Gynecology clinics at Jordan University Hospital. Initially, any female 18 years of age and older was asked to enroll in the study. Relevant data were gathered using a questionnaire composed of 30 questions, and body mass index (BMI) was determined from each participant's weight and height. The following variables were collected: socio-demographic, chronic diseases, and health status. Each variable's frequencies were reported, and the 95% confidence interval (95% CI) for each variable was calculated. For association analysis, Chi-square analysis was performed with an odds ratio (OR) and 95% CI. Multinomial logistic regression analysis was applied to a combination of independent variables and a dependent condition with covariate factors. RESULTS: The age-standardized prevalence of overweight/obese Jordanian women was 70.6% (95% CI 66.0-74.8%). On the other hand, the age-standardized prevalence of only obese women was 36.4 (95% Cl 31.9-41.2%). Furthermore, the association between age and overweight/obesity was significant (p<0.0001). The percentage of overweight and obesity started to be significant in the 30-39 year age group. Moreover, the OR for obesity ranged from 2.7 to 7.0 (p<0.05-0.01) for those women with only elementary education. Besides, high parity was significantly associated with obesity and elementary education. For chronic conditions, the percentages of hypertension, diabetes, hypertriglyceridemia, osteoporosis, and rheumatoid arthritis were significantly correlated with increased BMI in Jordanian women. With age adjustment, however, only hypertension was associated with obese level 3 with OR of 7.2 and 95% CI of 2.1-25.1 (p<0.01). CONCLUSION: There is a high prevalence of overweight/obesity among women in Jordan, which was related to high parity and low education level. This high prevalence of obesity increased the incidence of chronic diseases, such as hypertension. Therefore, community-based multiple strategies are required to combat obesity in Jordanian women.

Age of Natural Menopause Among Jordanian Women and Factors Related to Premature and Early Menopause.

OBJECTIVE: The aim of this study was to assess factors related to the onset of premature/early natural menopause among Jordanian women. METHODS: A cross-sectional study was conducted in early 2016. Subjects were enrolled based on random drop-off technique to the Obstetrics and Gynecology clinics at the Jordan University Hospital. Women 18 years of age and above were initially eligible to enroll, and women who had surgically induced menopause or specific disease were excluded from the analysis. Relevant data were collected using a questionnaire that included 30 questions. The following variables were collected: socio-demographic, body mass index, chronic conditions, diseases, reproductive characteristics, and health status. Hormone indicators of menopause were tested by measuring estrogen (E2) and follicle-stimulating hormone (FSH) levels. Age at natural menopause (ANM) was self-reported retrospectively and considered an independent variable against BMI, smoking, hormone therapy, and concomitant diseases. Association analysis and multinomial logistic regression were used to examine the associated factors of ANM with adjusted odds ratios (ORs), and their 95% confidence intervals (CIs) were reported. RESULTS: A total of 409 women were included in the analysis, aged between 20-75 years. The mean ANM in our sample was 48.5±5.0, with 2.7% of the women experienced premature menopause (ANM <40) and 7.8% early menopause (ANM 40-44). Within the menopause women (n=242), the percentage of women who had premature menopause was 4.5%, 13.6% with early menopause, and 21.1% with late menopause (ANM >52). Smoking was the major risk factor for premature/early menopausal age among Jordanian women with an OR of 2.46 (95% CI: 1.08-5.59, p<0.05). On the other hand, women with occasional arthritis symptoms and diseases such as hypertension, diabetes, dyslipidemia, and their combination were associated with average (45-52 years) or late menopause (>52 years). CONCLUSION: Smoking is the main contributor of premature/early menopause in Jordanian women. Increased awareness and public health policy about the adverse effects of smoking on women's reproductive health are needed.

Development and Validation of Liquid Chromatography Method for Determination of Glimepiride in Presence of (Vimto®) Soft Drinks in Rats: Application to Pharmacokinetics Studies.

CONTEXT: Diet and beverages are thought to have notable effects on drugs. Recently, this relationship has received significant consideration. AIMS: To develop and validate a simple, rapid, and sensitive method for the determination of glimepiride in rat serum. This will be performed using high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). Potential pharmacokinetic interactions between glimepiride and the soft drink, Vimto, will also be investigated in the serum of experimental rats. MATERIALS AND METHODS: HPLC-MS/MS was constructed and clarithromycin was used as an internal standard. RESULTS: The method was validated in terms of linearity, precision, accuracy, stability, and system suitability parameters. The method was found to be satisfactory and suitable for the determination of glimepiride. The precision of glimepiride was high (coefficient of variation, CV% <15%), the accuracy over all 3 days of validation was within the accepted criteria. Glimepiride peak serum concentration (C max) was 126.01 ng/mL and was reached within 1 h (T max) of administration. Mean area under curve (AUC) was 964.70 ng/mL and was reached within 24 h of administration. The Vimto soft drink significantly (P < 0.050) reduced glimepiride peak serum concentration to 57.87 ng/mL and was reached within 2 h of administration. AUC was significantly reduced to 335.04 ng*h/mL (P < 0.050). CONCLUSION: Glimepiride pharmacokinetic parameters such as C max and AUC were significantly affected by the Vimto soft drink. Therefore, this study developed a simple, rapid, and sensitive method for validation and determination of the effects of soft drinks on drugs using the LC-MS/MS method.

Critical pharmacokinetic and pharmacodynamic drug-herb interactions in rats between warfarin and pomegranate peel or guava leaves extracts.

BACKGROUND: In-depth information of potential drug-herb interactions between warfarin and herbal compounds with suspected anticoagulant blood thinning effects is needed to raise caution of concomitant administration. The current study aimed to investigate the impact of co-administration of pomegranate peel and guava leaves extracts, including their quality markers namely; ellagic acid and quercetin, respectively, on warfarin's in vivo dynamic activity and pharmacokinetic actions, in addition to potential in vitro cytochrome P450 enzymes (CYP) inhibition. METHODS: Influence of mentioned extracts and their key constituents on warfarin pharmacodynamic and kinetic actions and CYP activity were evaluated. The pharmacodynamic interactions were studied in Sprague Dawley rats through prothrombin time (PT) and International Normalized Ratio (INR) measurements, while pharmacokinetic interactions were detected in vivo using a validated HPLC method. Furthermore, potential involvement in CYP inhibition was also investigated in vitro on isolated primary rat hepatocytes. RESULTS: Preparations of pomegranate peel guava leaf extract, ellagic acid and quercetin in combination with warfarin were found to exert further significant increase on PT and INR values (p < 0.01) than when used alone (p < 0.05). Pomegranate peel extract showed insignificant effects on warfarin pharmacokinetics (p > 0.05), however, its constituent, namely, ellagic acid significantly increased warfarin Cmax (p < 0.05). Guava leaves extract and quercetin resulted in significant increase in warfarin Cmax when compared to control (p < 0.01). Furthermore, guava leaves extract showed a significant effect on changing the AUC, CL and Vz. Significant reduction in CYP2C8, 2C9, and 3A4 was seen upon concomitant use of warfarin with ellagic acid, guava leaves and quercetin, unlike pomegranate that insignificantly affected CYP activities. CONCLUSION: All combinations enhanced the anticoagulant activity of warfarin as the results of in vivo and in vitro studies were consistent. The current investigation confirmed serious drug herb interactions between warfarin and pomegranate peel or guava leaf extracts. Such results might conclude a high risk of bleeding from the co-administration of the investigated herbal drugs with warfarin therapy. In addition, the results raise attention to the blood-thinning effects of pomegranate peel and guava leaves when used alone.

Immunomodulatory effect of Moringa peregrina leaves, ex vivo and in vivo study.

This study was conducted to assess the in vivo and ex vivo immunomodulatory effect of the ethanol leaves extract of Moringa peregrina in Balb/c mice. For this study, five groups of 5 Balb/c mice were given a single acute subtoxic oral dose of the ethanolic extract at 1.13, 11.30, 23.40 and 113.4 mg/kg and the immunomodulatory effect was assessed on the 6th day following the ingestion. In the (non-functional) assessment, the effect of the extract on the body weight, relative lymphoid organ weight, splenic cellularity and peripheral blood hematologic parameters were evaluated. While in the immunomodulation assessment (functional), we investigated the effect of the extract on the proliferative capacity of splenic lymphocytes and peripheral T and B lymphocytes using mitogen blastogenesis, mixed allogeneic MLR and IgM-Plaque forming cells assays. The ingestion of M. peregrina extract caused a significant increase in the body weight, weight and number of cells of spleen and lymph nodes of the treated mice. Furthermore, the count of RBCs, WBCs, platelets, hemoglobin concentration and PCV % were increased by the extract treatment in a dose-dependent manner. M. peregrina enhanced the proliferative responses of splenic lymphocytes for both T cell and B-cell mitogens. Likewise, the mixed lymphocyte reaction MLR assay has revealed a T-cell dependent proliferation enhancement in the extract treated mice. Moreover, the oral administration of M. peregrina leaves extracts significantly increased PFCs/106 splenocytes in a dose-dependent manner. In conclusion, subtoxic acute doses of M. peregrina extract demonstrated significant potential as an immunomodulatory agent even at the lowest dose of 1.13 mg/kg.

The influence of Eruca sativa (Arugula) on pharmacokinetics of Sildenafil in rats.

OBJECTIVES: A drug like Sildenafil is commonly used for the treatment of erectile dysfunction. Eruca sativa is known as a garden plant used in folk medicine to enhance the sexual desire in males. Nevertheless, the interaction of Sildenafil and Eruca sativa was not studied. In the current study, we aimed to examine the influence of Eruca sativa on Sildenafil pharmacokinetics in rats. STUDY DESIGN: A crossover experiment with washout period of two weeks was conducted. To one group of animals, Eruca sativa was given as food and a drinking solution to rats for 12 hours before the day of the experiment. On the day of the experiment, the same group received 5 ml (50 mg/ml) orally and a half an hour later animals received 1 ml Sildenafil citrate (2.85 mg/kg) oral administrated to the study group. The other group of rats only received Sildenafil. Two-weeks later a cross-over design on the same animals was conducted. Blood samples were collected from optical vein on different time intervals, samples were analyzed using validated (HPLC-UV) method. RESULTS AND CONCLUSION: Pre-administration of Eruca sativa has increased Sildenafil Cmax from 226.72 to 345.25 ng/ml, (p<0.05). In addition, the AUC of Sildenafil has significantly increased when it was pre-administered with Eruca sativa (550.59 vs. 916.48 ng/ml*hr). Our findings suggest that co-administration of Eruca sativa with Sildenafil enhances the pharmacokinetics of Sildenafil in rats plasma.

A Liquid Chromatography-Tandem Mass Spectrometry Method for Evaluation of Two Brands of Enalapril 20 mg Tablets in Healthy Human Volunteers.

Enalapril is an angiotensin-converting enzyme inhibitor used for treatment of hypertension and chronic heart disease. Enalaprilat is its active metabolite responsible for the activity. This study aimed to develop and validate a method for enalapril and enalaprilat analysis and to determine the bioequivalence of two tablet formulae of enalapril. LC-MS/MS bioanalytical method was developed and validated and then applied to evaluate the bioavailability of two enalapril formulae. Antihyperglycemic sitagliptin was used as internal standard (IS). The method was accurate for the within- and between-days analysis, and precise CV% was <5%, being linear over the calibration range 1.0-200.0 ng/ml. Stability was >85% and the LOD was 0.907 and 0.910 ng/ml for enalapril and enalaprilat, respectively, and LLOQ was 1 ng/ml. The pharmacokinetic parameters Cmax, tmax, AUC0-72, and AUC0-∞ values of enalapril and enalaprilat of the two formulae were calculated and nonsignificant differences were found. A linearity, specific, accurate, and precise method was developed and applied for the analysis of enalapril and enalaprilat in human plasma after oral administration of two formulae of enalapril 20 mg tablets in healthy volunteers. Depending on the statistical analysis it was concluded that the two enalapril formulae were bioequivalent.

Stability Study and a 14-Day Oral Dose Toxicity in Rats of Plantain Leaf Extract (Plantago lanceolata L.) Syrup.

Plants have been used since antiquity to treat and prevent diseases. Plantain (Plantago lanceolata L.) is traditionally used for the treatment of the common cold and associated symptoms such as cough. This study was designed to evaluate the oral toxicity of plantain leaf extract-containing syrup. In preparation of the toxicological examination and to ensure the quality of the herbal preparation, analytical methods were developed and validated, and stability testing was performed. Physicochemical and microbial quality, thin layer chromatography patterns and high performance liquid chromatography fingerprints complied with the specifications during the entire period of stability testing. The marker substance, acteoside, remained within the stability-defining limits of 90%-110% for quantitative determinations. No hint of toxicity emerged from 14-day repeat dose toxicity testing in rats. The animals were given doses of 3, 6, or 12 mL of syrup per kg body weight by gavage twice daily. All animals showed normal appearance and behavior. Body and organ weights at the end of the study were similar to those in the control group. Overall, P. lanceolata syrup was found to be stable and non-toxic under the test conditions.

Pomegranate and licorice juices modulate metformin pharmacokinetics in rats.

OBJECTIVES: Food or drinks may significantly alter the pharmacokinetics and pharmacodynamics of drugs which may lead to adverse events. A drug such as metformin is widely used to regulate plasma glucose level and pomegranate and licorice have been identified to help in type-2 diabetes management. However, the interactions of the latter on metformin pharmacokinetics were not studied. Therefore, we aimed here to study the impact of pomegranate and licorice on metformin pharmacokinetics in rats. METHODS: Juices were given to rats for two days and half an hour before metformin (20 mg/kg) oral administration. Blood samples, then, were collected at different time intervals, processed and analyzed using validated reliable HPLC method. Plasma profile and pharmacokinetic parameters were calculated for each group. RESULTS AND CONCLUSION: Pre-administration of pomegranate significantly reduced metformin maximum plasma concentration from 1410 to 1031 ng/ml. On the other hand, pre-administration of licorice significantly delayed metformin reaching its maximum plasma concentration. In conclusion, pre-administration of pomegranate may potentially reduce efficacy of metformin while licorice might delay metformin action. Thus, both juices should be cautiously administrated with metformin, the mainstay drug for type-2 diabetes mellitus management.

Nationality, Gender, Age, and Body Mass Index Influences on Vitamin D Concentration among Elderly Patients and Young Iraqi and Jordanian in Jordan.

Vitamin D is necessary for maintaining and regulating calcium levels; thus, insufficiency of vitamin D increases the risk of many chronic diseases. This study aimed to examine vitamin D levels among Jordanian and Iraqi volunteers and find the relation between vitamin D level and lipid profile patients. Vitamin D levels were evaluated using enzyme-linked immunosorbent assay. For young healthy group subjects, vitamin D levels were 20.60 ± 5.94 ng/mL for Jordanian and 27.59 ± 7.74 ng/mL for Iraqi. Vitamin D concentrations for young males and females were 25.82 ± 8.33 ng/mL and 21.95 ± 6.39 ng/mL, respectively. Females wearing hijab were 20.87 ± 6.45 ng/mL, while uncovered females were 23.55 ± 6.04 ng/mL. For >40 years Iraqi subjects, vitamin D level for healthy was 29.78 ± 9.49 ng/mL and 23.88 ± 7.93 ng/mL for hyperlipidemic subjects. Vitamin D levels for overweight and obese healthy groups were significantly higher (P < 0.050) than those for the hyperlipidemic patients groups. Vitamin D levels for males were significantly higher than females and were significantly higher for healthy than those hyperlipidemic Iraqi patients. These findings showed that vitamin D levels are affected by age, nationality, gender, and health statues and highlight the importance of vitamin D supplementation for groups with low levels particularly old, hijab wearing females, and hyperlipidemic groups.

Crystal structure of 5-[bis-(methyl-sulfon-yl)meth-yl]-1,3-dimethyl-5-(methyl-sulfon-yl)pyrimidine-2,4,6(1H,3H,5H)-trione.

In the title compound, C10H16N2O9S3, the pyrimidine ring of the 1,3-dimethyl barbituric acid moiety has an envelope conformation with the C atom carrying the methyl-sulfonyl and bis-(methyl-sulfon-yl)methyl substituents as the flap. The dihedral angle between mean plane of the pyrimidine ring and the S/C/S plane is 72.4 (3)°. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure.

Bis(methyl-sulfon-yl)methane.

In the title compound, C3H8O4S2, the two central S-C(H2) bond lengths are almost identical [1.781 (2) and 1.789 (2) Å]. In the crystal, each mol-ecule utilizes CH2 and CH3 bonds to form weak C-H⋯O hydrogen bonds to six other mol-ecules, thus linking mol-ecules into a three-dimensional network.

Crystal structure of 1,3-di-cyclo-hexyl-4,5-dimethyl-1H-imidazol-3-ium-2-carbodi-thio-ate chloro-form monosolvate.

The title compound, C18H28N2S2·CHCl3, crystallizes as a zwitterion. The C-S bonds are almost equivalent, with lengths of 1.666 (3) and 1.657 (3) Å. The S-C-S bond angle is expanded to 129.54 (16)° and the N-C-N angle is reduced to the tetra-hedal value of 108.8 (2)°. In the crystal, adjacent mol-ecules are linked via C-H⋯S hydrogen bonds, forming chains along [100]. The chloro-form solvent mol-ecule, which is disordered over two positions [occupancy ratio = 0.51 (2):0.49 (2)], is linked to the chain by bifurcated C-H⋯(S,S) hydrogen bonds.

Anti-inflammatory aminoacetylenic isoindoline-1,3-dione derivatives modulate cytokines production from different spleen cell populations.

We recently designed a series of N-[4-(t-amino-yl)-but-2-yn-1-yl] isoindoline-1,3-diones as anti-inflammatory compounds, called ZM compounds. These ZM compounds were categorized according to the nature of the cyclic amino groups into ZM2, ZM3, ZM4, and ZM5 and were shown to reduce carrageenan-induced inflammation, inhibit cyclooxygenase (1 and 2) and have less adverse effects than the common non-steroidal anti-inflammatory drugs. In the present study, we are examining the potential effects of ZM compounds in modulating cytokines production in vivo and in vitro from stimulated spleen cells, CD4+ CD25+ve T regulatory cells and CD4+CD25-ve T helper cells. Six hours following oral administration of 20mg/kg of ZM4 and ZM5 compounds reversed LPS-induced TGF-ß suppression whereas ZM2, ZM3, ZM4, and ZM5 reversed LPS-induced TNF-α and IL-12 increase in mice spleen. In addition, increasing concentrations of ZM2, ZM4 and ZM5 increased significantly TGF-ß1 production, whereas ZM3, ZM4 and ZM5 suppressed only TNF-α production in LPS and LPS+PMA stimulated spleen cells. Furthermore, only ZM5, enhanced significantly TGF-ß1 production from LPS and LPS+PMA stimulated CD4+CD25+ve cells (p<0.001), whereas none of the ZM compounds modulated TNF-α from CD4+CD25-ve T helper cells. These results indicate that ZM5 (N-{4-(2-Azepan-1-yl)-but-2-yn-1-yl}isoindoline-1,3-dione) enhances TGF-ß production from CD4+CD25+ve cells independent of protein kinase C activation and suggest that all ZM compounds suppress TNF-α from monocytes/macrophage cells. In conclusion, these ZM compounds have potential to be used use as anti-inflammatory agents and further studies to show the possibility of utilizing these basic aminoacetylenic isoindolines in autoimmune mediated inflammatory diseases are warranted.

2-Bromo-1,3-diisopropyl-4,5-dimethyl-1H-imidazol-3-ium dicyanidoargentate.

The title structure, (C(11)H(20)BrN(2))[Ag(CN)(2))], is built up from an approximately C(2v)-symmetric imidazolium cation and a nearly linear dicyanidoargentate anion [N-Ag-N = 176.6 (9)° and Ag-C-N = 178.8 (9) and 177.2 (11)°]. These two constituents are linked by a remarkably short inter-action between the Br atom of the imidazolium cation [C-Br = 1.85 (3) Å] and one N atom of the cyanidoargentate anion [Br⋯N = 2.96 (2) Å], which is much less than the sum of the van der Waals radii (3.40 Å). The crystal studied was twinned by merohedry.

1,3-Diisopropyl-4,5-dimethyl-imidazolium benzene-sulfonate.

In the title salt, C(11)H(21)N(2) (+)·C(6)H(5)O(3)S(-), which has two cation-anion pairs in the asymmetric unit, the two imidazolium cations are linked to two separate acceptor O atoms of one of the benzene-sulfonate anions through aromatic C-H⋯O hydrogen bonds, while the second anion is unassociated.

Plasma concentrations of 25-hydroxyvitamin D among Jordanians: Effect of biological and habitual factors on vitamin D status.

BACKGROUND: Vitamin D is cutaneously synthesized following sun exposure (vitamin D3) as well as it is derived from dietary intake (vitamin D3 and D2). Vitamin D2 and D3 are metabolized in the liver to 25-hydroxyvitamin D (25(OH)D). This metabolite is considered the functional indicator of vitamin D stores in humans. Since Jordan latitude is 31°N, cutaneous synthesis of vitamin D3 should be sufficient all year round. However, many indications reveal that it is not the case. Thus, this study was conducted to determine the 25(OH)D status among Jordanians. METHODS: Three hundred healthy volunteers were enrolled in a cross sectional study; 201 females and 99 males. 25(OH)D and calcium concentrations were measured by enzyme linked immunosorbent assay and spectroscopy techniques, respectively. All participants filled a study questionnaire that covered age, sex, height, weight, diet, and dress style for females. Females were divided according to their dress style: Western style, Hijab (all body parts are covered except the face and hands), and Niqab (all body parts are covered including face and hands). RESULTS: The average plasma 25(OH)D levels in males and females were 44.5 ± 10.0 nmol/l and 31.1 ± 12.0 nmol/l, respectively. However, when female 25(OH)D levels were categorized according to dress styles, the averages became 40.3, 31.3 and 28.5 nmol/l for the Western style, Hijab and Niqab groups, respectively. These 25(OH)D levels were significantly less than those of males (p < 0.05, 0.001, 0.001, respectively). In addition, the plasma 25(OH)D levels of the Western style group was significantly higher than those of Hijab and Niqab groups (p < 0.001). Furthermore, dairy consumption in males was a positive significant factor in vitamin D status. Even though calcium concentrations were within the reference range, the Hijab and Niqab-dressed females have significantly less plasma calcium levels than males (p < 0.01). CONCLUSIONS: Very low plasma 25(OH)D levels in females wearing Hijab or Niqab are highly attributed to low sunlight or UVB exposure. In addition, most of males (76%) and Western style dressed females (90%) have 25(OH)D concentrations below the international recommended values (50 nmol/l), suggesting that although sun exposure should be enough, other factors do play a role in these low concentrations. These findings emphasize the importance of vitamin D supplementation especially among conservatively dressed females, and determining if single nucleotide polymorphisms of the genes involved in vitamin D metabolism do exist among Jordanians.