Induction of fatty liver by Coleus forskohlii extract through enhancement of de novo triglyceride synthesis in mice

A standardized extract of Coleus forskohlii root protects rats from ovariectomy-induced loss of bone mass and strength, and impaired bone material by osteogenic and anti-resorptive mechanisms

INTRODUCTION

In obese humans, Coleus forskohlii root extract (CF) protects against weight gain owing to the presence of forskolin, an adenylate cyclase (AC) activator. As AC increases intracellular cyclic adenosine monophosphate (cAMP) levels in osteoblasts that has an osteogenic effect, we thus tested the skeletal effects of a standardized CF (CFE) in rats.

METHODS

Concentrations of forskolin and isoforskolin were measured in CFE by HPLC. CFE and forskolin (the most abundant compound present in CFE) were studied for their osteogenic efficacy in vitro by alkaline phosphatase (ALP), cAMP and cyclic guanosine monophosphate (cGMP) assays. Femur osteotomy model was used to determine the osteogenic dose of CFE. In growing rats, CFE was tested for its osteogenic effect in intact bone. In adult ovariectomized (OVX) rats, we assessed the effect of CFE on bone mass, strength and material. The effect of forskolin was assessed in vivo by measuring the expression of osteogenic genes in the calvarium of rat pups.

RESULTS

Forskolin content in CFE was 20.969%. CFE increased osteoblast differentiation and intracellular cAMP and cGMP levels in rat calvarial osteoblasts. At 25 mg/kg (half of human equivalent dose), CFE significantly enhanced calcein deposition at the osteotomy site. In growing rats, CFE promoted modeling-directed bone formation. In OVX rats, CFE maintained bone mass and microarchitecture to the level of sham-operated rats. Moreover, surface-referent bone formation in CFE treated rats was significantly increased over the OVX group and was comparable with the sham group. CFE also increased the pro-collagen type-I N-terminal propeptide: cross-linked C-telopeptide of type-I collagen (PINP : CTX-1) ratio over the OVX rats, and maintained it to the sham level. CFE treatment decreased the OVX-induced increases in the carbonate-to-phosphate, and carbonate-to-amide-I ratios. CFE also prevented the OVX-mediated decrease in mineral crystallinity. Nanoindentation parameters, including modulus and hardness, were decreased by OVX but CFE maintained these to the sham levels. Forskolin stimulated ALP, cAMP and cGMP in vitro and upregulated osteogenic genes in vivo.

CONCLUSION

CFE, likely due to the presence of forskolin displayed a bone-conserving effect via osteogenic and anti-resorptive mechanisms resulting in the maintenance of bone mass, microarchitecture, material, and strength.

Hepatotoxicity due to herbal dietary supplements: Past, present and the future

Dietary supplements (DS) constitute a widely used group of products comprising vitamin, mineral, and botanical extract formulations. DS of botanical or herbal origins (HDS) comprise nearly 30% of all DS and are presented on the market either as single plant extracts or multi-extract-containing products. Despite generally safe toxicological profiles of most products currently present on the market, rising cases of liver injury caused by HDS - mostly by multi-ingredient and adulterated products - are of particular concern. Here we discuss the most prominent historical cases of HDS-induced hepatotoxicty - from Ephedra to Hydroxycut and OxyELITE Pro-NF, as well as products with suspected hepatotoxicity that are either currently on or are entering the market. We further provide discussion on overcoming the existing challenges with HDS-linked hepatotoxicity by introduction of advanced in silico, in vitro, in vivo, and microphysiological system approaches to address the matter of safety of those products before they reach the market.

Effect of Forskolin on Body Weight, Glucose Metabolism and Adipocyte Size of Diet-Induced Obesity in Mice

The purpose of this study was to investigate the effects of forskolin on body weight, glucose metabolism and fat cell diameter in high-fat diet-induced obese mice. Four-week-old male mice (C57BL/6) were randomly assigned to 1 of 3 treatment groups: a high-fat diet plus 5% dimethyl sulfoxide (vehicle), high-fat diet plus 2 mg/kg of forskolin (dissolved in 5% dimethyl sulfoxide) and high-fat diet plus 4 mg/kg of forskolin (dissolved in 5% dimethyl sulfoxide). Forskolin or dimethyl sulfoxide was administered intraperitoneally every two days. The results indicated that no significant difference was observed in the body weight, feed intake and serum lipid parameters among groups at 20 weeks of age. The blood glucose levels were significantly reduced in the groups treated with 2 mg/kg of forskolin before glucose tolerance test. Forskolin administration linearly decreased blood glucose levels of high-fat diet-fed mice at 90 min and total area under curve (AUC) after insulin tolerance test. The subcutaneous adipocyte diameter was significantly reduced in the groups treated with 2 mg/kg of forskolin. Forskolin administration linearly reduced the gonadal adipocyte diameter of high-fat diet-fed mice. Forskolin significantly reduced the differentiation of murine mesenchymal stem cells into adipocytes and this was accompanied by a decrease in intracellular triglyceride content and an increase in glycerol concentration in the culture medium. The subcutaneous adipocyte diameter, gonadal adipocyte diameter and total AUC of insulin tolerance test were moderately negatively correlated with the concentration of forskolin in the high-fat diet-induced obese model. These results demonstrate that forskolin can regulate glucose metabolism and reduce fat cell diameter of high-fat diet-fed mice and inhibit the adipocyte differentiation of murine mesenchymal stem cells.

Coleus forskohlii Extract Attenuated the Beneficial Effect of Diet-Treatment on NASH in Mouse Model

Obesity is one of the main causes of non-alcoholic steatohepatitis (NASH), which is associated with impaired liver functions including drug metabolism. Coleus forskohlii extract (CFE) is a popular ingredient of weight loss dietary supplements in Japan. In this study, we examined the effect of CFE on the treatment of NASH. C57BL/6 mice (male, 10-wk-old) were fed a NASH diet (high-fat, low-methionine, and choline-deficient diet) for 12 wk to establish NASH. Then, we examined the effect of 0.5% (w/w) CFE in diet during diet-treatment (change to control diet) and/or treadmill-exercise (45 min at 20 m/min, 5 d/wk) to improve NASH for 3 wk. After experimental period, lipids profiles and liver functional markers in the blood, and hepatic lipid content and major CYP subtype mRNA expression and activity in liver were measured. Diet-treatment, but not exercise decreased liver weight and hepatic lipid contents in NASH induced mice. CFE attenuated the effects of diet-treatment which reduced liver weight, even though body weight and adipose tissue weight were reduced. Further, CFE significantly increased liver microsomal CYP1A1, CYP1A2, CYP2C, and CYP3A activities in each condition, and CYP inductions were greater in diet-treatment group compared to those in exercise group. These results suggest that taking CFE should be avoided during diet-treatment of NASH, especially in patients under medication.

Nationwide Online Survey Enables the Reevaluation of the Safety of Coleus forskohlii Extract Intake Based on the Adverse Event Frequencies

The formulations of the functional ingredients of dietary supplements was studied with a small number of subjects, with a particular focus on their effectiveness, but not enough to evaluate their safety. In this regard, the reevaluation and estimation of the safe use of marketed products, with regards to their adverse event (AE) frequencies, are important. To address this issue, a post-marketing nationwide online survey was conducted for the herbal ingredient Coleus forskohlii extract (CFE), a popular weight-loss ingredient. The questionnaire included product names, adherence to the claimed amount, and AE experiences. The safe intake amount was estimated by the relationship between the claimed amount of CFE and the frequencies of AEs of each product. The number of users who experienced AEs was 75 (10.5% of all users). Gastrointestinal symptoms accounted for 92.0% (n = 69) of all AEs, and diarrhea alone accounted for 81.3% (n = 61). The amount of CFE was significantly associated with the occurrence of diarrhea (p = 0.005). The fitted curve showed that the safe intake amount of CFE was less than 250 mg/day; however, considering its effectiveness, 500 mg/day of CFE might be acceptable. In conclusion, nationwide online surveys of users enable us to confirm and reevaluate the safety of herbal supplements.

Anthocyanins from Cornus kousa ethanolic extract attenuate obesity in association with anti-angiogenic activities in 3T3-L1 cells by down-regulating adipogeneses and lipogenesis

Cornus kousa the Korean dogwood has been traditionally used in East Asia as therapeutic traditional medicine however biological activities of Cornus kousa have not been investigated previously. The aim of the present study was to evaluate anti-obesity activities coupled with anti-angiogenic activities of anthocyanins rich fraction of ethanolic leaf extract of Cornus kousa (ELECk) in HUVECs and 3T3- L1 cells. Dried plants leaves were extracted with 70% ethanol and anthocyanin fraction (AnT Fr) was obtained by eluting the ethanolic extract through non-polar macroporous resin and further purification by HPLC. Antiangiogenic activities were determined by antiproliferative effect of AnT Fr on HUVECs. In the presence of various concentrations of AnT Fr, 3T3-L1 preadipocytes were induced to differentiate. Lipid accumulation in differentiated adipocytes were quantified by Oil-Red O staining. AnT Fr significantly suppressed angiogenesis by inhibiting proliferation and tube formation of HUVECs via downregulating VEGRF 2, PI3K, β-catenin, NF-kB, and Akt1 in a dose dependent manner. AnT Fr inhibited lipid accumulation by down-regulating adipogenesis and lipogenesis promoting signaling proteins, PPARγ, CCAAT, C/EBPα, aP2, FAS, and LPL, however enhanced AMPK activation to p-AMPK in 3T3 cells quantified and expressed by western blotting. AnT Fr inhibit lipid accumulation by regulating adipogenesis and lipogenesis related genes and signaling proteins. The anti-obesity activities exerted by Cornus kousa are associated with antiangiogenic activities of anthocyanins rich fraction of Cornus kousa. Hence the presence of bioactive anthocyanins, Cornus kosa, is a good candidate for nutraceutical and pharmaceutical formulation for treating or controlling obesity.