Mathematical models for predicting protodioscin in tropical forage grasses.

Protodioscin is a saponin present in grasses that can lead to losses in animal production. Our hypothesis was that mathematical models can accurately and precisely predict the protodioscin concentration in tropical grasses. We evaluated the ability of four mathematical models to describe the protodioscin concentration in Brachiaria and Panicum cultivars with different regrowth periods. Six cultivars of Panicum: Aruana, Massai, Mombaça, Tanzânia, Tamani, and Zuri; and five of Brachiaria-grass: Marandu, Paiaguás, Piatã, Xaraés and Basilisk. Protodioscin concentration evaluations were carried out at 51, 84, 110, and 111 days of age. Linear, Quadratic, Exponential, and Logarithmic models were evaluated, and the adequacy of the models was verified. The models were compared for accuracy and precision by pairwise mean squared error analysis and the delta Akaike information criterion. The models did not differ from each other in terms of accuracy and precision. The exponential model showed a high ability to explain the observed variability between protodioscin concentration and plant age for Brachiaria grasses. Panicum grasses have constant protodioscin concentration. Mathematical models are capable of predicting the protodioscin concentration in grasses of the genus Brachiaria based on plant age. We recommend Exponential model to predict the concentration of protodioscin in Brachiaria grasses.

[Research progress of steroidal saponins in Paris polyphylla var. yunnanensis and their microbial transformation].

Steroidal saponins, important natural organic compounds in Paris polyphylla var. yunnanensis, have good biological activity. Structural modification of steroidal saponins by microbial transformation could produce a large number of products with novel structures and excellent bioactivity, which can provide functional compounds for the research and development of steroidal drugs. This study summarized the research progress in steroidal saponins and their microbial transformation in P. polyphylla var. yunnanensis. P. polyphylla var. yunnanensis contains 112 steroidal saponins, 8 of which are used as substrates in 35 transformation reactions by 25 microbial species, with the highest transformation rate of 95%. Diosgenin is the most frequently used substrate. Furthermore, the strains, culture medium, reaction conditions, transformation rate, transformation reaction characteristics, and biological activities of the transformed products were summarized. This review may provide reference for the further research on microbial transformation of steroidal saponins in P. polyphylla var. yunnanensis.

Steroid glycosides isolated from Paris polyphylla var. chinensis aerial parts and paris saponin II induces G1/S-phase MCF-7 cell cycle arrest.

In our previous research on Vietnamese medicinal plants, we found that the ethanolic extract of the aerial parts of Paris polyphylla var. chinensis exhibited cytotoxic effects in vitro in the MCF-7 human cancer cell line. Here, we used combined chromatographic separations to isolate six compounds including a new steroid glycoside, paripoloside A (3), and five known compounds, from the butanol extract of the aerial parts of P. polyphylla. We unambiguously elucidated their structures based on spectroscopic data (proton and carbon-13 nuclear magnetic resonance, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, correlation spectroscopy, and high-resolution electrospray ionization mass spectroscopy data), and chemical reactions. Among the isolated compounds, paris saponin II (PSII) had the strongest cytotoxic effects against MCF-7 breast cancer cells. Interestingly, PSII significantly increased the expression of p53, p21, p27, and Bax protein levels and significantly suppressed the expression of cyclin D1 and retinoblastoma protein. These data suggest that PSII may induce G1/S phase cell cycle arrest and apoptosis pathway development in MCF-7 cells. Furthermore, the MCF-7 breast cancer cells mechanism of PSII was also investigated using molecular docking. Together, our results demonstrate that isolated compounds from P. polyphylla are promising candidates as breast cancer inhibitors.

Comparative study of steroidal sapogenins content in leaves of five Agave species.

BACKGROUND: Agaves are mainly used to produce alcoholic beverages such as tequila, mezcal and bacanora. However, the leaves constitute more than 50% of the plant and are not used in the production process, so they are considered waste. This plant material can be used as a source of bioactive compounds such as terpenes, flavonoids and saponins. Therefore, the objective of this study was to characterize the aglycone type of saponins and to quantify three steroidal sapogenins in leaves of five Agave species collected in different regions of Guerrero and Oaxaca, Mexico. RESULTS: Analysis by gas chromatography-flame ionization detection of the hydrolyzed methanolic extracts showed that diosgenin and tigogenin were the most abundant sapogenins identified in the five Agave species. Differences in the content of these sapogenins were found in the same species collected in different localities. The leaves of Agave americana var. oaxacensis L. (Oaxaca) had the highest diosgenin-derived saponin content, while the leaves of A. angustifolia Haw. (Guerrero) had the highest tigogenin-derived saponin content. Only in A. cupreata was sarsasapogenin identified, all three sapogenins occurring in the leaves of this species. For the first time, information is provided on the aglycones of the saponins produced in A. potatorum Zucc. and A. karwinskii Zucc. CONCLUSION: This study made it possible to compare the content of diosgenin and tigogenin-derived saponins in leaves of Agave species from Guerrero and Oaxaca. This information will be useful for better utilization of this plant material and add value to the process of mezcal elaboration. © 2022 Society of Chemical Industry.

Novel diosgenin-1,4-quinone hybrids: Synthesis, antitumor evaluation, and mechanism studies.

In this research, a series of novel diosgenin-1,4-quinone hybrids were synthesized and evaluated in antiproliferative assays against three human cancer cell lines (MCF-7, HepG2, and HeLa). Structure-activity relationship analysis revealed that the activities depended on the type of 1,4-quinone moiety. Among them, hybrid 11a exhibited significant cytotoxicity against the HepG2 cell line with a IC50 of 1.76 µM, which was 35-fold more potent than diosgenin (IC50 = 43.96 µM). Western blot analysis showed that hybrid 11a upregulated Bax, Cl-caspase-3/9, and Cl-PARP levels, and downregulated Bcl-2 level of HepG2 cell line. Meanwhile, hybrid 11a could increase the generation of intracellular reactive oxygen species. The molecular docking study revealed an interaction between hybrid 11a and NQO1 enzyme. Our present studies suggested that hybrid 11a as a potential substrate for NQO1 enzyme could be a promising anticancer agent for further investigation.

The power of hyphenated chromatography-Time of flight mass spectrometry for unequivocal identification of spirostanes in bodybuilding dietary supplements.

A previously unidentified purported botanical ingredient was found in dietary supplements marketed for anabolic benefits. In an attempt to assess the 'naturalness' of a group of steroid-like compounds called laxogenins, a UHPLC-QToF method was developed. Several dietary supplements claim to contain 5α-hydroxy laxogenin, which is a derivative of a naturally occurring spirostane-type steroid, laxogenin. Although laxogenin has been isolated from the rhizomes of Smilax sieboldii, 5α-hydroxy laxogenin has not been isolated or reported from any natural source. These derivatives of laxogenins have untested anabolic properties. Due to the low UV absorbance of the spirostanes, a mass spectrometric method in positive ion mode was developed for unambiguous identification of laxogenin and closely related compounds. To show the utility of the developed method, twelve dietary supplements labeled to contain 5α-hydroxy laxogenin or laxogenin as 5α-hydroxy laxogenin were analyzed as a proof-of-concept. Five supplements did not contain any 5α-hydroxy laxogenin, whereas in the remaining seven samples, spirostane-type contaminants were identified along with the labeled 5α-hydroxy laxogenin. The identity of some of these contaminants was established based on reference standards along with mass fragmentation patterns. One of the unlabeled contaminants was identified as the phytosteroid saponin, diosgenin, a common starting precursor of several steroidal drugs. Several synthetic derivatives of diosgenin were identified in the eight products. These findings indicate that the labeled 5α-hydroxy laxogenin along with other spirostanes found in supplements are synthetic and signify a lack of quality controls. Additionally, an unlabeled, anabolic androgenic steroid, arimistane, an aromatase inhibitor, was also identified in one product. Laxogenin, was not detected in any of the samples analyzed during this investigation.

Fermentation of yam (Dioscorea spp. L.) by indigenous phytase-producing lactic acid bacteria strains.

The use of lactic bacteria in the development of functional foods has increased in recent years. In addition to their probiotic characteristics, they can ferment a variety of substrates, such as cereals, roots, and tubers. Phytase producer lactic acid bacteria strains and their behavior during the fermentation process of yam-based food were studied. Leuconostoc lactis CCMA 0415, Lactobacillus plantarum CCMA 0744, and Lactobacillus fermentum CCMA 0745 were selected due to phytase production, pH reduction, and growth during 24 h of fermentation. Oxalate activity was not detected in all assays, suggesting its concentration was reduced due to the bleaching process. Among the selected strains, L. lactis CCMA 0415 appeared to be a promising strain in yam-based fermentations because it maintained a cell viability above 8 log CFU/mL and did not reduce diosgenin concentrations (around 8.0 µg/mL) after fermentation for 24 h, thereby, generating a potentially functional yam food. Furthermore, this strain promoted the decrease of pH value from 6.1 to 3.8 and produced 8.1 g/L lactic acid, at 6 h of fermentation. The L. lactis CCMA 0415 was reported as a starter culture in fermented products based on cereals, roots, and tubers.

Purification of the total steroidal saponins from fenugreek seeds ( Trigonella foenum- graecum L.) using aqueous two-phase system and determination of diosgenin content using micellar electrokinetic chromatography method.

The total steroidal saponins, particularly its major steroidal sapogenin (diosgenin), are the main active principles of fenugreek seed extract. In this study, an ethanol-salt aqueous two-phase system (ATPS) was explored for the purification of the total steroidal saponins, and the process conditions were optimized by response surface methodology (RSM). Under the optimized conditions, the RSM predicted recovery of the total steroidal saponins in the top phase of ATPS was 97.9%, which agreed with the average experimental recovery (98.3 ± 4.2% ( n = 6)). Moreover, a rapid micellar electrokinetic chromatography (MEKC) method was developed for the determination of diosgenin from extracts. The diosgenin content in the ATPS top phase extract was 3-fold higher than that in crude extract, suggesting this ATPS having a great potential for purification pharmacological active ingredients from fenugreek seeds.

Liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (QTOF/MS) assay for quantification of protodioscin in Brachiaria grasses.

This work aimed to develop and validate a method to detect and quantify protodioscin in Brachiaria grasses using ultraperformance liquid chromatography (UPLC) coupled to high-resolution quadrupole time-of-flight mass spectrometry. Samples were extracted by acetonitrile-water 50:50 v/v mixture and ultrasonication. The mobile phase consisted of 5 mM ammonium acetate in water-methanol and acetonitrile containing 0.1% formic acid. The parameters used to validate the method for determining protodioscin comprised determination of the selectivity, ionization suppression/enhancement (matrix effect), linearity of the calibration curve, the limit of detection (LOD), the lower limit of quantitation (LLOQ), and the precision and accuracy of the method. The LLOQ of protodioscin was determined as 0.1 µg mL-1, and the LOD was 0.03 µg mL-1. The developed method was applied for determining protodioscin levels in B. decumbens collected from three pastures where sheep showed clinical signs of photosensitization. The obtained values ranged from 0.71% to 1.12%. Thus, the developed method for determining protodioscin in Brachiaria grasses by LC coupled to high-resolution quadrupole time-of-flight mass spectrometry showed high accuracy, precision, and sensitivity.

Tribulus terrestris Protects against Male Reproductive Damage Induced by Cyclophosphamide in Mice.

Tribulus terrestris (TT) has been considered as a potential stimulator of testosterone production, which has been related with steroidal saponins prevailing in this plant. Cyclophosphamide (CP) is the most commonly used anticancer and immunosuppressant drug, which causes several toxic effects, especially on the reproductive system. Patients who need to use CP therapy exhibit reduced fertility or infertility, which impacts both physically and emotionally on the decision to use this drug, especially among young men. We hypothesized that the treatment with TT dry extract would protect the male reproductive system against CP toxicity. Mice received dry extract of TT (11 mg/kg) or vehicle by gavage for 14 days. Saline or CP was injected intraperitoneally at a single dose (100 mg/kg) on the 14th day. Animals were euthanized 24 h after CP administration, and testes and epididymis were removed for biochemical and histopathological analysis and sperm evaluation. The dry extract of TT was evaluated by HPLC analysis and demonstrated the presence of protodioscin (1.48%, w/w). CP exposure increased lipid peroxidation, reactive species, and protein carbonylation and altered antioxidant enzymes (SOD, CAT, GPx, GST, and GR). Moreover, acute exposure to CP caused a reduction on 17 ß-HSD activity, which may be related to the reduction in serum testosterone levels, histopathological changes observed in the testes, and the quality of the semen. The present study highlighted the role of TT dry extract to ameliorate the alterations induced by CP administration in mice testes, probably due to the presence of protodioscin.

Can treatment of Brachiaria decumbens (signal grass) improve its utilisation in the diet in small ruminants?-a review.

Brachiaria decumbens is an extremely productive tropical grass due to its aggressive growth habit and its adaptation to a varied range of soil types and environments. As a result of the vast availability, treated B. decumbens demonstrates as a promising local material that could be utilised as an improved diet for sheep and goats. Despite the fact that the grass significantly increases weight gains in grazing farm animals, there were many reports of general ill-thrift and sporadic outbreaks of photosensitivity in livestock due to the toxic compound of steroidal saponin found in B. decumbens. Ensiling and haymaking were found to be effective in removing toxin and undesirable compounds in the grass. Biological treatments using urea, activated charcoal, polyethylene glycol, and effective microorganisms were found to be useful in anti-nutritional factor deactivation and improving the nutritive values of feedstuffs. Besides, oral administration of phenobarbitone showed some degree of protection in sheep that fed on B. decumbens pasture. In this review, we aim to determine the effect of B. decumbens toxicity and possible treatment methods on the grass to be used as an improved diet for small ruminant.

LC-MS determination of steroidal glycosides from Dioscorea deltoidea Wall cell suspension culture: Optimization of pre-LC-MS procedure parameters by Latin Square design.

In this paper, the ultrasound assisted extraction method for isolation of steroidal glycosides from D. deltoidea plant cell suspension culture with a subsequent HPLC-MS determination was developed. After the organic solvent was selected via a two-factor experiment the optimization via Latin Square 4 × 4 experimental design was carried out for the following parameters: extraction time, organic solvent concentration in extraction solution and the ratio of solvent to sample. It was also shown that the ultrasound assisted extraction method is not suitable for isolation of steroidal glycosides from the D. deltoidea plant material. The results were double-checked using the multiple successive extraction method and refluxing extraction. Optimal conditions for the extraction of steroidal glycosides by the ultrasound assisted extraction method were: extraction time, 60 min; acetonitrile (water) concentration in extraction solution, 50%; the ratio of solvent to sample, 400 mL/g. Also, the developed method was tested on D. deltoidea cell suspension cultures of different terms and conditions of cultivation. The completeness of the extraction was confirmed using the multiple successive extraction method.

Detection and quantification of phenethylamines in sports dietary supplements by NMR approach.

Phenethylamines (PEAs) are popular substances found in weight-loss and sports nutrition supplements. They are generally pharmacologically active and primarily affect the sympathetic nervous system. Many PEAs are synthetic chemicals and are on the prohibited list of the World Anti-Doping Agency. In this study, nuclear magnetic resonance (NMR) spectroscopy was applied to detect and identify the presence of PEAs in sports dietary supplements without the need for chromatographic separation or pre-knowledge on formulation. Eight PEAs, viz. phenethylamine, synephrine, oxilofrine, hordenine, ß-methylphenethylamine, N-methyltyramine, octopamine and deterenol, were identified from 32 dietary supplements sold in the US market. Furthermore, a quantitative NMR method was developed and validated for simultaneous determination of the concentrations of the PEAs. The study demonstrated that NMR could be a potential tool to monitor and detect PEAs or other ingredients in dietary supplements.

Comparative metabolic profiling of Costus speciosus leaves and rhizomes using NMR, GC-MS and UPLC/ESI-MS/MS.

Costus speciosus had been used in oriental systems of medicines, to treat diverse ailments. The present study was focused on NMR, GC-MS and UPLC/ESI-MS/MS-based metabolic profiling of C. speciosus. This metabolic study resulted in the identification of 91 and quantification of 69 metabolites. Caffeic acid derivatives previously unreported in C. speciosus were also identified. High quantity of steroidal saponins namely methyl protogracillin (297.97 ± 0.07 mg/g dried wt.) and dioscin (158.72 ± 0.27 mg/g dried wt.) were observed in butanol fraction of rhizomes. Health care metabolites including caffeic acid (37.88 ± 0.04 mg/g dried wt.) and trehalose (75.12 ± 0.08 mg/g dried wt.) were also detected in ethyl acetate and aqueous fractions of rhizomes, respectively. Metabolites of nutraceutical and biological significance including eremanthine (5.14 ± 0.68%, peak area), tocopherols (~22%), sterols (~25%) were also identified from hexane fractions of rhizomes and leaves using GC-MS. The analytical techniques used had successfully differentiated metabolites composition among leaves and rhizomes.

[Rapid prediction of the content of polyphyllin in various species of Paris by infrared spectrometry].

Polyphyllin is the main active constituent in Paris which was a traditional Chinese medicine. In order to evaluate the quality of Paris rapidly and ensure the efficacy in clinical therapy, we quantified the contents of polyphyllin Ⅰ, polyphyllin Ⅱ and polyphyllin Ⅶ using infrared spectroscopy with partial least squares regression(PLSR). The method for evaluating the quality of Paris was established. Infrared spectra of 78 samples from various species in different origins were collected. The contents of polyphyllin Ⅰ, Ⅱ and Ⅶ were determined by high performance liquid chromatography(HPLC). The HPLC data were combined with the spectral data to predict the contents of three polyphyllin rapidly. Multiplicative signal correction(MSC), standard normal variate(SNV), orthogonal signal correction(OSC), first derivative and second derivative were utilized for the spectral preprocessing. Then, the optimized spectral data were used to establish the quantitative prediction model based on PLSR. The results showed that the best spectral pretreatment of polyphyllin Ⅰ and Ⅱ were MSC+OSC+2nd Der and that of polyphyllin Ⅶ was MSC+SNV+OSC+2nd Der. In the quantitative calibration model, the determination coefficients (R²) of polyphyllin Ⅰ, polyphyllin Ⅱ and polyphyllin Ⅶ were 0.930 8, 0.934 8 and 0.912 3, respectively while the Root mean square error of estimation(RMSEE) were 1.855 0, 0.632 3 and 0.001 6 mg•g⁻¹, respectively. In the verification model, the R² of polyphyllin Ⅰ, polyphyllin Ⅱ and polyphyllin Ⅶ were 0.948 8, 0.703 6 and 0.801 7, respectively, and the root mean square error of prediction(RMSEP)were 1.704 6, 1.227 8 and 0.002 0 mg•g⁻¹, respectively. Because of the predictive value of quantitative model was closed to the real value, the effect of the model was good. The model of polyphyllin Ⅰ and Ⅱ were better than that of polyphyllin Ⅶ. The developed method was non-destructive, fast, and accurate. It was feasible to determine the content of polyphyllin in Paris.

Content of the Saponin Protodioscin in Brachiaria spp. from the Eastern Plains of Colombia.

Protodioscin is used as a marker of saponin content that could cause hepatotoxicity in ruminants. In Brachiaria spp. from two regions of the Colombian Eastern Plains (east mountain range of the Andean-"piedemonte" and Ariari River Valley) were determined this metabolite at 14 and 28 days post-cutting under different climatic conditions. No protodioscin was detected in B. dictyoneura or B. humidicola. In B. brizantha, B. decumbens and B. ruziziensis x B. decumbens x B. brizantha (hybrid), protodioscin content corresponded to an interaction between species, post-cutting time and season. Concentrations ≥1% (minimum toxic level) were recorded in B. decumbens and the hybrid, and to a lesser extent in B. brizantha. The concentration of protodioscin was higher at 28 days, when the pastures are suitable for consumption. B. brizantha accumulated the lowest saponin concentration, whereas the hybrid had the highest levels, particularly in the "piedemonte" and during drought (3.37%). Dry season favored the protodioscin concentration in B. decumbens (in river valley) and in the hybrid (in "piedemonte"). In the latter, there was a positive correlation with temperature and a negative with humidity, which are typical characteristics of dry periods. This is the first report of protodioscin content in the hybrid.

Saponin Profile of Wild Asparagus Species.

The aim of this work was to study the saponin profiles from spears of different wild asparagus species in the context of its genetic diversity aside from geographical seed origin. They included Asparagus pseudoscaber Grecescu, Asparagus maritimus (L.) Mill., Asparagus brachiphyllus Turcz., Asparagus prostrates Dumort., and Asparagus officinalis L. The saponin analysis by LC-MS has shown that saponin profile from wild asparagus is similar to that previously described for triguero asparagus from Huétor-Tájar landrace (triguero HT), which had not ever been reported in the edible part of asparagus. All the samples, except A. officinalis, were characterized for having saponins distinct to protodioscin and the total saponin contents were 10-fold higher than those described for commercial hybrids of green asparagus. In particular, A. maritimus from different origins were rich in saponins previously found in triguero HT. These findings supported previous suggestion, based on genetic analysis, about A. maritimus being the origin of triguero HT. Multivariate statistics including principal component analysis and hierarchical clustering analysis were used to define both similarities and differences among samples. The results showed that the greatest variance of the tested wild asparagus could be attributed to differences in the concentration of particular saponins and this knowledge could be a tool for identifying similar species.

Combined Application of UHPLC-QTOF/MS, HPLC-ELSD and 1 H-NMR Spectroscopy for Quality Assessment of DA-9801, A Standardised Dioscorea Extract.

INTRODUCTION: DA-9801, a standardised 50% aqueous ethanolic extract of a mixture of Dioscorea japonica and D. nipponica, is a botanical drug candidate for the treatment of diabetic neuropathy, which finished its US phase II clinical trials recently. An advanced quality control method is needed for further development of DA-9801, considering its high contents of both primary and secondary metabolites. OBJECTIVE: Development of a quality assessment strategy for DA-9801, based on the combination of UHPLC-QTOF/MS, HPLC-ELSD, and 1 H-NMR spectroscopy. METHODS: The method was developed and tested with 15 batch products of DA-9801. The steroidal saponins of DA-9801 were tentatively identified by UHPLC-QTOF/MS and were quantified with the validated HPLC-ELSD method. Primary metabolites of DA-9801 were identified and profiled using 1 H-NMR spectrometry. The batch-to-batch equivalence of DA-9801 was tested with the 1 H-NMR spectra using spectral binning, correlation analysis, and principal component analysis. RESULTS: Six major saponins of DA-9801 were tentatively identified by UHPLC-QTOF/MS. Among them, protodioscin and dioscin were quantified by the validated HPLC-ELSD method. Twenty-six metabolites were identified in 1 H-NMR spectra. The similarity between DA-9801 batches could be evaluated with the NMR spectra of DA-9801. The 1 H-NMR method also revealed that two Dioscorea species contributed distinct amino acids to the contents of DA-9801. CONCLUSION: This study validates the effectiveness of UHPLC-QTOF/MS, HPLC-ELSD, and 1 H NMR-combined method for quality control of DA-9801 and its crude materials. Copyright © 2016 John Wiley & Sons, Ltd.

Isolation and chemoenzymatic treatment of glycoalkaloids from green, sprouting and rotting Solanum tuberosum potatoes for solanidine recovery.

The estimation of glycoalkaloids in the flesh of different types of decayed potatoes was evaluated. The results showed that turned green and also sprouting or rotting potato flesh contain high amounts of toxic solanine and chaconine, exceeding by 2-5-fold the recommended limit, and ranging from 2578±86mg/kg to 5063±230mg/kg of dry weight potato flesh. For safety consideration, these decayed potatoes should be systematically set aside. To avoid a net economic loss and encourage the removal of this hazardous food, a recycling process was investigated to generate added-value compounds from the toxic glycoalkaloids. A simple chemo-enzymatic protocol comprising a partial acidic hydrolysis followed by an enzymatic treatment with the ß-glycosidase from Periplaneta americana allowed the efficient conversion of α-chaconine to solanidine.

Consumption of Japanese Yam Improves Lipid Metabolism in High-Cholesterol Diet-Fed Rats.

We investigated the effects of dietary Japanese yam (Dioscorea japonica Thunb.) on lipid metabolism. Male Wistar rats (6 wk old) were fed a high-cholesterol diet for 6 wk and then supplemented with 26% of Japanese yam or 0.5% of its constituent diosgenin for a further 4 wk of high-cholesterol feeding (C6-J4 and C6-D4 groups, respectively). In the C6-J4 group, body weight gains significantly decreased, but skeletal muscle fiber sizes in quadriceps significantly increased compared with the other groups. Furthermore, Japanese yam supplementation resulted in the reduction of triglyceride contents in their liver, quadriceps, and intra-abdominal visceral fat. Diosgenin supplementation resulted in an increase in the numbers of skeletal muscle fibers and decrease in the fat accumulations in liver and of the lipid contents in quadriceps. Although quadriceps cholesterol contents decreased concomitantly with increased serum HDL-cholesterol in both the groups, fecal bile acid, fecal cholesterol contents, and fecal weight were higher in the C6-J4 group than in the C6-D4 group. Meanwhile, we demonstrated that Japanese yam inhibited micellar cholesterol solubility in vitro in a concentration-dependent manner. These results suggest that Japanese yam is more effective than diosgenin in reducing fat accumulation and improving cholesterol metabolism during chronic consumption of a high-cholesterol diet.