Genotoxicity and 28-day oral toxicity studies of a functional food mixture containing maltodextrin, white kidney bean extract, mulberry leaf extract, and niacin-bound chromium complex

Is chromium(III) pharmacologically relevant? An update focused on studies with diabetic rodent models

A decade ago, the author assessed the status of chromium as the trivalent ion as an essential element and as a therapeutic agent based on rodent studies for this journal. The current review was undertaken to update considerations regarding the status of chromium, focusing on studies of Cr supplementation of diabetic rodent models over the last decade. Cr can no longer be considered an essential trace element for humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. The review of studies on the effects of Cr on rat models of diabetes is updated, and the results continue to suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr. Recent studies primary utilizing rodents suggest two potential complementary but also contradictory modes of action for Cr(III) at a molecular level.

Safety evaluation of kaempferol glycosides-rich standardized roasted goji berry leaf extract

Goji berry leaf (GL) has been used for medicinal foods for its pharmacological effects, including anti-oxidative and anti-obesity activities. Nevertheless, toxicological information on GL is limited for developing health functional ingredient. The aim of the research was to evaluate the single dose acute, 14-day repeated oral toxicity, and genotoxicity of standardized roasted GL extract (rGL) rich in kaempferol-3-O-sophoroside-7-O-glucoside. Tested rGL was found to be stable as kaempferol-3-O-sophoroside-7-O-glucoside, showing 0.7-2.1% of analytical standard variance. According to the single dose toxicity for 14 days, the lethal dose of rGL was determined to be ≥ 2000 mg/kg. Repeated doses of 0-1000 mg/kg of rGL per day for 14 days did not show any toxicity signs or gross pathological abnormalities. No genotoxic signs for the rGL treatment appeared via bacterial reverse mutation up to 5000 μg/plate. There was no significant increase in chromosomal aberration of rGL irrespective of metabolic activation by using CHO-K1 cells (p > 0.05). Regarding carcinogenic toxicity, chromosomal aberrations were not induced at 2000 mg of rGL/kg by using the in vivo bone marrow micronucleus test (p > 0.05). Results from the current study suggest that rGL could be used as a functional ingredient to provide various effects with safety assurance.

Improvement of Glycemic Control by a Functional Food Mixture Containing Maltodextrin, White Kidney Bean Extract, Mulberry Leaf Extract, and Niacin-Bound Chromium Complex in Obese Diabetic db/db Mice

Steady-fiber granule (SFG) is a mixture containing maltodextrin, white kidney bean extract, mulberry leaf extract, and niacin-bound chromium complex. These active ingredients have been shown to be associated with improving either hyperglycemia or hyperlipidemia. This study was undertaken to evaluate the potential of SFG in the regulation of blood glucose homeostasis under obese diabetic conditions. Accordingly, db/db mice (8 weeks old) were administered with SFG at doses of 1.025, 2.05, or 5.125 g/kg BW daily via oral gavage for 4 weeks. No body weight loss was observed after SFG supplementation at all three doses during the experimental period. Supplementation of SFG at 2.05 g/kg BW decreased fasting blood glucose, blood fructosamine, and HbA1c levels in db/db mice. Insulin sensitivity was also improved, as indicated by HOMA-IR assessment and oral glucose tolerance test, although the fasting insulin levels were no different in db/db mice with or without SFG supplementation. Meanwhile, the plasma levels of triglyceride were reduced by SFG at all three doses. These findings suggest that SFG improves glycemic control and insulin sensitivity in db/db mice and can be available as an option for functional foods to aid in management of type 2 diabetes mellitus in daily life.

Toxicological assessment of enzyme-treated Zizania latifolia extract: Oral toxicology and genotoxicity in rats

Zizania latifolia Turcz. has long been used as a food source in Southeast Asia. The grains, stems, and leaves of Z. latifolia and its major component, tricin, have also been studied to determine their biological activities. Previously, we hydrolyzed the aerial part of Z. latifolia using an enzyme mixture to maximize the tricin content of the Z. latifolia extract. However, the safety of enzyme-treated Z. latifolia extract (ETZL; DermaNiA™) has not yet been determined. In this study, we performed an in vivo 90-day repeated-dose evaluation and genotoxicity study to assess the toxicological potential of ETZL. EZTL did not exhibit genotoxicity in the bacterial reverse mutation test, in vitro chromosomal aberration assay, or in vivo micronucleus test. Moreover, no changes in body weight or hematological and serum biological parameters were observed in male or female rats under high-dose EZTL treatment (5000 mg/kg body weight (bw)/day) for 90 days with a 4-week recovery period. Significant changes were noted in the forestomach, kidneys, and adrenal glands in the test groups, but these changes, or tendency for recovery, were not observed in the recovery group. Based on these data, the no adverse effect level was determined to be 1250 mg/kg bw/day in rats.

Synergistic Protective Effects of Different Dietary Supplements Against Type 2 Diabetes via Regulating Gut Microbiota

Diabetes mellitus is a global health problem, and its prevalence continues to increase. Dietary supplements, including probiotics, prebiotics, and plant extracts, have been shown to alleviate diabetes. In this study, the synergistic effects of two types of dietary supplements were investigated in a mouse model of type 2 diabetes mellitus (T2DM). Sixty mice were divided into the following six groups: control, model (induced by a high-fat diet and intraperitoneal injection of streptozotocin), drug (metformin), probiotic (Lactobacillus spp.), formula A (probiotics, plant extracts, and soybean peptide), and formula B (probiotics, prebiotics, and soybean peptide). All three dietary interventions (probiotic, formula A, and formula B groups) significantly reduced the blood glucose level and oral glucose tolerance level and effectively improved some biochemical parameters (e.g., chronic inflammation, oxidative stress, and blood lipid level) and regulated gut microbiota. Notably, formula B exhibited a better ability on reducing the blood glucose level, regulating the gut microbiota, and increasing the short-chain fatty acid levels compared with the probiotics alone and formula A. Thus, formula B may exert synergistic protective effects against T2DM through a mechanism involving probiotics and prebiotics of gut microbiota regulation. This study provides a theoretical basis for the application of probiotic dietary supplements to the treatment of T2DM.

Toxicity as prime selection criterion among SARS-active herbal medications

We present here a new selection criterion for prioritizing research on efficacious drugs for the fight against COVID-19: the relative toxicity versus safety of herbal medications, which were effective against SARS in the 2002/2003 epidemic. We rank these medicines according to their toxicity versus safety as basis for preferential rapid research on their potential in the treatment of COVID-19. The data demonstrate that from toxicological information nothing speaks against immediate investigation on, followed by rapid implementation of Lonicera japonica, Morus alba, Forsythia suspensa, and Codonopsis spec. for treatment of COVID-19 patients. Glycyrrhiza spec. and Panax ginseng are ranked in second priority and ephedrine-free Herba Ephedrae extract in third priority (followed by several drugs in lower preferences). Rapid research on their efficacy in the therapy - as well as safety under the specific circumstances of COVID-19 - followed by equally rapid implementation will provide substantial advantages to Public Health including immediate availability, enlargement of medicinal possibilities, in cases where other means are not successful (non-responders), not tolerated (sensitive individuals) or just not available (as is presently the case) and thus minimize sufferings and save lives. Moreover, their moderate costs and convenient oral application are especially advantageous for underprivileged populations in developing countries.

A 90-day Sub-chronic Oral Toxicity Assessment of Mulberry Extract in Sprague Dawley Rats

Mulberry extract from Fructus Mori contains an anthocyanin pigment and has been widely used as a food additive in China and other Eastern Asian countries. Only few research has been done on toxicological profiling of mulberry extract for its safety evaluation; however, the data is inconclusive. In the current study, mulberry extract of 4200, 1400, or 466 mg/kg were orally administrated to Sprague Dawley rats for 90 consecutive days followed by a recovery period of 28 days. No abnormalities were detected in body weights, food intake, ophthalmological, hematological, coagulation, clinical chemistry, and organ weights parameters. Discoloration of urine (red, purple, and brown) and feces (black), along with bedding material (purple) were observed in the 4200 mg/kg group. Further, microscopic examination revealed brown granules in the renal tubular cells for rats in 4200 and 1400 mg/kg groups. Since these changes were associated with excretory effect of the extract, the No Observed Adverse Effect Level was determined to be 4200 mg/kg, which was equivalent to the 1058.5 mg/kg of anthocyanin.

Subchronic Study of a White Kidney Bean (Phaseolus vulgaris) Extract with α-Amylase Inhibitory Activity

Common bean extract as a dietary supplement has received increased attention globally owing to its α-amylase inhibitory activity. The objective of this study was to evaluate the toxicity of a white kidney bean (Phaseolus vulgaris) extract by a repeated-dose 90-day subchronic oral toxicity study in Sprague-Dawley rats. In the subchronic toxicity study, 80 rats were orally administrated with white kidney bean extract at doses of 4, 2, and 1 g/kg body weight daily for 90 days. The results showed that the white kidney bean extract at doses up to 4 g/kg/day did not induce significant changes in body weight, organ weight, food consumption, hematology, serum biochemistry, and histopathology in rats, as compared to the control. The no-observed-adverse-effect level (NOAEL) of white kidney bean extract was determined to be >4 g/kg/day for both male and female rats, under the experimental conditions of this study.