Papers by Hellen Oketch-Rabah
Planta Medica
Cranberry is a popular ingredient in dietary supplements in the U. S. and is commonly used for pr... more Cranberry is a popular ingredient in dietary supplements in the U. S. and is commonly used for preventing urinary tract infections. Because of its popularity in dietary supplements, the U. S. Pharmacopeial Convention has developed quality standards for cranberry ingredients. The purpose of this review was to determine if there are safety issues that should preclude the admission of cranberry ingredients from the development of U. S. Pharmacopeial Convention quality standards. Based on the totality of the data, the U. S. Pharmacopeial Convention concluded that cranberry ingredients are not known to be associated with serious risks to human health when consumed properly in dietary supplements and therefore were admitted for standard development. Although published clinical and animal data indicated that cranberry is not associated with serious adverse effects, interactions with warfarin and kidney stone formation were identified as potential risks. Studies have reported contradictory ...
Planta Medica
Willow bark (Salix spp.) is an ingredient in some dietary supplements. No serious adverse effects... more Willow bark (Salix spp.) is an ingredient in some dietary supplements. No serious adverse effects were reported from trials of willow bark extracts delivering 120 – 240 mg salicin (the purported active constituent) daily for up to 8 weeks. All studies involved adults only; none involved special subpopulations such as pregnant or breastfeeding women, or children. The most common adverse effects associated with willow bark are gastrointestinal; a few allergic reactions were also reported. Some publications advise caution when taking willow bark. There is a risk of increased bleeding in vulnerable individuals, salicylates cross the placenta and are eliminated slowly in newborns, some persons are sensitive or allergic to aspirin, and children are at risk of Reye syndrome. Concurrent use with other salicylate-containing medicines increases these risks. Metabolism of 240 mg salicin from willow bark could yield 113 mg of salicylic acid, yet dietary supplement products are not required to b...
Journal of Agricultural and Food Chemistry
Clinical Pharmacology & Therapeutics
Clinical Pharmacology & Therapeutics
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, Jan 4, 2018
Planta medica, Jan 13, 2018
The attraction of novel foods proceeds alongside epidemic cardiovascular disease, diabetes, obesi... more The attraction of novel foods proceeds alongside epidemic cardiovascular disease, diabetes, obesity, and related risk factors. Dieticians have identified chia () as a product with a catalog of potential health benefits relating to these detriments. Chia is currently consumed not only as seeds, but also as oil, which brings about similar effects. Chia seeds and chia seed oil are used mainly as a food commodity and the oil is also used popularly as a dietary ingredient used in various dietary supplements available in the U. S. market. Chia seed is rich in -linolenic acid, the biological precursor to eicosapentaenoic acid, a polyunsaturated fatty acid, and docosahexaenoic acid. Because the body cannot synthesize -linolenic acid, chia has a newfound and instrumental role in diet. However, the inconclusive nature of the scientific community's understanding of its safety warrants further research and appropriate testing. The focus of this work is to summarize dietary health benefits o...
Cyr61, a member of the CCN gene family, was isolated and identified by differential expression be... more Cyr61, a member of the CCN gene family, was isolated and identified by differential expression between estrogen receptor (Expositive and ER-negative breast cancer cells. Cyr61 is a Iigand for the integrin ctvß3, which is involved in tumorigenesis and angiogenesis (formation of new blood vessels). We showed previously that expression of Cyr61 in HRG-transfected MCF-7 cells is greatly increased compared to parental MCF-7 cells. We also showed that Cyr61 is expressed in all the invasive, metastatic, HRGexpressing, and ER-negative breast cancer cell lines. Moreover, Cyr61 was detected in about 30% of invasive human breast tumor biopsies. Most significantly, an anti-Cyr61 blocking antibody abolishes the invasiveness and migration of HRG-expressing breast cancer cells in vitro. To understand the role of Cyr61 in breast cancer progression, the human Cyr61 cDNA was introduced to ERnegative, HRG-negative breast cancer cells. Cyr61-expressing cells showed a growth advantage in serum-depleted conditions. The preliminary results suggest that Cyr61 is sufficient to promote estrogen independence and anti-estrogen resistance of breast cancer cells both in vitro and in vivo. Cyr61-expressing breast cancer cells are invasive in vitro and tumorigenic in vivo. The mechanism involved in Cyr61-induced tumor formation and aggressiveness is mediated via specific activation of the MAPK and PI3K/AKT pathways. Blocking of Cyr61 expression in aggressive breast cancer cells by specific anti-sense oligonucleotides or by constitutive expression of anti-sense Cyr61 messages results in phenotypic reversion, including reacquisition of E2 requirement for growth and anti-E2 sensitivity, in addition to reduced invasiveness and matrix protease activity in vitro, and decreased tumoriginecity. Taken together, these results strongly indicate that Cyr61 plays a critical role in breast cancer progression.
The Journal of nutrition, 2016
The increasing consumption of amino acids from a wide variety of sources, including dietary suppl... more The increasing consumption of amino acids from a wide variety of sources, including dietary supplements, natural health products, medical foods, infant formulas, athletic and work-out products, herbal medicines, and other national and international categories of nutritional and functional food products, increases the exposure to amino acids to amounts far beyond those normally obtained from the diet, thereby necessitating appropriate and robust safety assessments of these ingredients. Safety assessments of amino acids, similar to all food constituents, largely rely on the establishment of an upper limit [Tolerable Upper Intake Level (UL)] considered to be a guide for avoiding high intake, above which adverse or toxic effects might occur. However, reliable ULs have been difficult or impossible to define for amino acids because of inadequate toxicity studies in animals and scarce or missing clinical data, as well as a paucity or absence of adverse event reporting data. This review exa...
Nutrition Reviews, 2016
Dietary supplements are widely used by military personnel and civilians for promotion of health. ... more Dietary supplements are widely used by military personnel and civilians for promotion of health. The objective of this evidence-based review was to examine whether supplementation with l-arginine, in combination with caffeine and/or creatine, is safe and whether it enhances athletic performance or improves recovery from exhaustion for military personnel. Information from clinical trials and adverse event reports were collected from 17 databases and 5 adverse event report portals. Studies and reports were included if they evaluated the safety and the putative outcomes of enhanced performance or improved recovery from exhaustion associated with the intake of arginine alone or in combination with caffeine and/or creatine in healthy adults aged 19 to 50 years. Information related to population, intervention, comparator, and outcomes was abstracted. Of the 2687 articles screened, 62 articles meeting the inclusion criteria were analyzed. Strength of evidence was assessed in terms of risk of bias, consistency, directness, and precision. Most studies had few participants and suggested risk of bias that could negatively affect the results. l-Arginine supplementation provided little enhancement of athletic performance or improvements in recovery. Short-term supplementation with arginine may result in adverse gastrointestinal and cardiovascular effects. No information about the effects of arginine on the performance of military personnel was available. The available information does not support the use of l-arginine, either alone or in combination with caffeine, creatine, or both, to enhance athletic performance or improve recovery from exhaustion. Given the information gaps, an evidence-based review to assess the safety or effectiveness of multi-ingredient dietary supplements was not feasible, and therefore the development of a computational model-based approach to predict the safety of multi-ingredient dietary supplements is recommended.
Journal of Dietary Supplements, 2012
This paper reviews the literature concerning the ethnobotany, phytochemistry, and pharmacology of... more This paper reviews the literature concerning the ethnobotany, phytochemistry, and pharmacology of Mondia whitei, which is also known as Mondia whytei, African ginger or simply as mondia. Mondia is used in many parts of Africa as a traditional remedy to improve appetite and libido, as a galactagogue, as a fertility medication, and as an antidepressant. In African countries, where it is used medicinally, the most commonly cited use is as an aphrodisiac. The scientific studies reviewed in this report employed either in vivo rodent models or isolated organ techniques, and therefore the results cannot be directly extrapolated to humans. Nevertheless, these studies provide scientific evidence that support the traditional uses of mondia as an aphrodisiac and an antidepressant. Based on the safety data available in the literature, mondia is reasonably expected to be safe when prepared and used according to traditional practices.
Journal of Chemical Crystallography, 2003
The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-... more The crystal and molecular structure of the antimalarial compound 5,7-methoxy-8-(3-methyl-1-buten-3-ol)-coumarin, C16H18O5, Mr = 290.3 Da, has been determined from X-ray diffraction data. The material crystallizes in the monoclinic space group P21/c with 4 molecules per unit cell of dimensions a = 8.9044(9), b = 17.623(1), c = 10.175(1) Å, ß = 113.97(1)°, crystal density Dc = 1.322 g/cm3. The structure
International Journal of Oncology, 2003
Black cohosh is an increasingly popular alternative to estrogen replacement therapy for the relie... more Black cohosh is an increasingly popular alternative to estrogen replacement therapy for the relief of menopausal symptoms, primarily hot flushes. However, an important consideration for long-term therapy is potential toxicity and carcinogenicity. Therefore, we undertook a study to assess the estrogenic activity of black cohosh to examine its safety for those with, or at high risk of developing, breast cancer. Several assays were utilized as listed: RNAse protection assays, which ascertain the regulation of the expression of E2-responsive genes; estrogen-responsive-element (ERE)-luciferase, which determines modulation of the ER function by transactivation of the ERE; the Ishikawa cell system, which has an E2-regulated endogenous alkaline phosphatase; and colony formation of ER-expressing breast cancer cells, which indicates possible progression of early stage breast cancer into a more aggressive state. Black cohosh extracts did not demonstrate estrogenic activity in any of these assay systems. This is an encouraging step in the assessment of the safety of black cohosh for treatment of menopausal hot flushes.
Mental Health, Religion & Culture, 2006
... 1976. Zulu thought patterns and symbolism , Cape Town: David Phillip. ... Medicine is used no... more ... 1976. Zulu thought patterns and symbolism , Cape Town: David Phillip. ... Medicine is used not only in the context of herbs but also in a wide range of items, eg amulets, charms, spells, incantations, and gesticulations as medication (Owuor, 199925. Owuor, BO. 1999. ...
Journal of Herbs, Spices & Medicinal Plants, 1997
Many Aloe species are valued for the healing properties associated with the leaf tissues, a facto... more Many Aloe species are valued for the healing properties associated with the leaf tissues, a factor that has led to over-exploitation of natural populations and endangerment of some local Kenyan species. While trade in native, wild aloe stocks has been banned by a presidential declaration, depletion continues, indicating the need to grow these plants as a field crop. The chemical
Pharmaceutical Biology, 1999
ABSTRACT This paper describes the in vitro antimalarial activity of eight species of plants popul... more ABSTRACT This paper describes the in vitro antimalarial activity of eight species of plants popularly used traditionally to treat malaria in Kenya. Organic and aqueous extracts from different parts of the plants were tested. Generally, a stronger antimalarial activity was observed in the organic extracts. The most active extracts were of Vernonia brachycalyx O. Hoffm. Schreber. (Compositae) leaves which showed an IC 50 of 6.6 µg/ml for methylene chloride: ethyl acetate (1:1) extracts, while the aqueous and more polar methanolic extracts gave IC 50 values of 29.6 and 30 µg/ml, respectively. The findings of this study support the use of this plant as a traditional remedy for malaria. The rest of the plants tested gave IC 50 values between 30–100 µg/ml.
Uploads
Papers by Hellen Oketch-Rabah