Variation of Serum Lycopene in Response to 100% Watermelon Juice: An Exploratory Analysis of Genetic Variants in a Randomized Controlled Crossover Study

The Anticancer Potential of Plant-Derived Nutraceuticals via the Modulation of Gene Expression

Current studies show that approximately one-third of all cancer-related deaths are linked to diet and several cancer forms are preventable with balanced nutrition, due to dietary compounds being able to reverse epigenetic abnormalities. An appropriate diet in cancer patients can lead to changes in gene expression and enhance the efficacy of therapy. It has been demonstrated that nutraceuticals can act as powerful antioxidants at the cellular level as well as anticarcinogenic agents. This review is focused on the best studies on worldwide-available plant-derived nutraceuticals: curcumin, resveratrol, sulforaphane, indole-3-carbinol, quercetin, astaxanthin, epigallocatechin-3-gallate, and lycopene. These compounds have an enhanced effect on epigenetic changes such as histone modification via HDAC (histone deacetylase), HAT (histone acetyltransferase) inhibition, DNMT (DNA methyltransferase) inhibition, and non-coding RNA expression. All of these nutraceuticals are reported to positively modulate the epigenome, reducing cancer incidence. Furthermore, the current review addresses the issue of the low bioavailability of nutraceuticals and how to overcome the drawbacks related to their oral administration. Understanding the mechanisms by which nutraceuticals influence gene expression will allow their incorporation into an “epigenetic diet” that could be further capitalized on in the therapy of cancer.

Watermelon and L-Citrulline in Cardio-Metabolic Health: Review of the Evidence 2000-2020

PURPOSE OF REVIEW

Watermelon (Citrullus lanatus) distinctively contains L-citrulline and L-arginine, precursors of nitric oxide (NO), along with polyphenols and carotenoids suggesting a role in cardio-metabolic health. The goal of this paper is to review the preclinical and clinical trial evidence published from 2000 to 2020 to assess watermelon intake and L-citrulline, as a signature compound of watermelon, on cardiovascular and metabolic outcomes, and to identify future directions important for establishing dietary guidance and therapeutic recommendations actionable by health care professionals, patients, and the general public.

RECENT FINDINGS

Watermelon and L-citrulline supplementation reduced blood pressure in human trials. Evidence for benefits in lipids/lipoprotein metabolism is emerging based on human literature and consistently reported in animal models. A role for watermelon intake in body weight control, possibly through satiety mechanisms, warrants further research. Likewise, improved glucose homeostasis in chemically and diet-induced animal models of diabetes is apparent, though limited data are available in humans. Emerging areas include brain and gut health indicated by NO bioavailability in all tissues, and evidence suggesting improvements in gut barrier function and altered microbial composition after watermelon intake that may influence metabolite pools and physiological function. Watermelon fruit contains unique vaso- and metabolically-active compounds. Accumulating evidence supports regular intake for cardio-metabolic health. Future research to determine the amount and frequency of watermelon/citrulline intake for desired outcomes in different populations requires attention to advance preventative and therapeutic strategies for optimal health and disease risk reduction.

Daily 100% watermelon juice consumption and vascular function among postmenopausal women: A randomized controlled trial

BACKGROUND AND AIMS

Watermelon juice is a rich food source of cardioprotective compounds such as arginine, citrulline, and lycopene. Preventative interventions are warranted as risk of cardiovascular disease increases among women after menopause, and age alone is an independent risk factor for vascular dysfunction. Thus, this study evaluated the effects of 100% watermelon juice on measures of vascular function.

METHODS AND RESULTS

In this randomized, double-blind, placebo-controlled, crossover trial, 21 healthy postmenopausal women were randomized to consume two 360 mL servings of 100% watermelon juice per day or an isocaloric placebo for four weeks. Following a two-week washout period, they consumed the other beverage for an additional four weeks. Before and after each treatment arm, a fasting blood sample was taken for measurement of serum arginine, citrulline, lycopene, glucose, and insulin. Assessments of vascular function included pulse pressure, pulse wave velocity, 24-h ambulatory blood pressure, and flow-mediated dilation. General linear mixed models with intent-to-treat analyses were used to examine the effects of the intervention. Despite a significant treatment effect for circulating lycopene (p = 0.002), no changes in arginine, citrulline, or any vascular measures were observed. Although the juice intervention resulted in a slight but significant increase in fasting serum glucose (p = 0.001), changes in glucose homeostasis were not clinically significant.

CONCLUSION

In contrast to findings from previous studies in younger adults and those with pre-existing hypertension, measures of vascular function in this cohort of healthy postmenopausal women were not impacted by supplemental watermelon juice. CLINICALTRIALS.

GOV IDENTIFIER

NCT03626168.

Targeted capture sequencing identifies genetic variations of GRK4 and RDH8 in Han Chinese with essential hypertension in Xinjiang

Essential hypertension is a common cardiovascular disease with complex etiology, closely related to genetic and environmental factors. The pathogenesis of hypertension involves alteration in vascular resistance caused by sympathetic nervous system (SNS) and renin angiotensin system (RAS). Susceptibility factors of hypertension vary with regions and ethnicities. In this study, we conducted target capture sequencing on 54 genes related to SNS and RAS derived from a collection of Han nationality, consisting of 151 hypertension patients and 65 normal subjects in Xinjiang, China. Six non-synonymous mutations related to hypertension were identified, including GRK4 rs1644731 and RDH8 rs1801058, Mutations are predicted to affect 3D conformation, force field, transmembrane domain and RNA secondary structure of corresponding genes. Based on protein interaction network and pathway enrichment, GRK4 is predicted to participate in hypertension by acting on dopaminergic synapse, together with interacting components. RDH8 is involved in vitamin A (retinol) metabolism and consequent biological processes related to hypertension. Thus, GRK4 and RDH8 may serve as susceptibility genes for hypertension. This finding provides new genetic evidence for elucidating risk factors of hypertension in Han nationality in Xinjiang, which in turn, enriches genetic resource bank of hypertension susceptibility genes.

100% Watermelon Juice as a Food-First Intervention to Improve Cognitive Function: Ancillary Findings from a Randomized Controlled Trial

Lycopene exhibits neuroprotective properties due to its antioxidant and anti-inflammatory functionality. As watermelon is a rich source of lycopene, pasteurized watermelon juice provides lycopene in its most bioavailable form. This study examined relationships between circulating lycopene, cognitive performance, and biomarkers of oxidative stress and inflammation in response to pasteurized 100% watermelon juice supplementation. A placebo-controlled, randomized, double-blind, crossover trial was conducted with postmenopausal women (n = 16, 60 + 4.1 years). Participants consumed two 360 mL servings of pasteurized 100% watermelon juice or a placebo beverage for 4 weeks. Fasting blood samples were collected, and cognitive tests were administered to assess various neurocognitive domains. Statistical analyses included mixed models and Spearman correlations. Serum lycopene exhibited a significant treatment effect (p = 0.002) with a mean increase of 81%. However, this increase was not associated with changes in oxidative stress, inflammation, or cognitive function. Additional research is warranted to determine dose-durational effects for promoting cognition.