Inhibitory effects of compounds isolated from Dioscorea batatas Decne peel on particulate matter-induced pulmonary injury in mice

Botanical formulation HX110B ameliorates PPE-induced emphysema in mice via regulation of PPAR/RXR signaling pathway

Chronic obstructive pulmonary disease (COPD), an inflammatory lung disease, causes approximately 3 million deaths each year; however, its pathological mechanisms are not fully understood. In this study, we examined whether HX110B, a mixture of Taraxacum officinale, Dioscorea batatas, and Schizonepeta tenuifolia extracts, could suppress porcine pancreatic elastase (PPE)-induced emphysema in mice and its mechanism of action. The therapeutic efficacy of HX110B was tested using a PPE-induced emphysema mouse model and human bronchial epithelial cell line BEAS-2B. In vivo data showed that the alveolar wall and air space expansion damaged by PPE were improved by HX110B administration. HX110B also effectively suppresses the expression levels of pro-inflammatory mediators including IL-6, IL-1β, MIP-2, and iNOS, while stimulating the expression of lung protective factors such as IL-10, CC16, SP-D, and sRAGE. Moreover, HX110B improved the impaired OXPHOS subunit gene expression. In vitro analysis revealed that HX110B exerted its effects by activating the PPAR-RXR signaling pathways. Overall, our data demonstrated that HX110B could be a promising therapeutic option for COPD treatment.

The genus Dioscorea L. (Dioscoreaceae), a review of traditional uses, phytochemistry, pharmacology, and toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Dioscorea, a member of the Dioscoreaceae family, comprises approximately 600 species and is widely distributed across temperate and tropical regions such as Asia, South Africa, and North America. The traditional medicinal uses of Dioscorea have been documented in Asian and African pharmacological systems. In Asia, this genus is traditionally used to treat respiratory illnesses, rheumatism, diabetes, diarrhea, dysentery, and other conditions. In Africa, this genus has been used to treat human immunodeficiency virus and ring worms. However, the traditional medicinal practices in North America rarely mention the use of this genus.

AIM OF THE STUDY

The aim of this review is to comprehensively review the genus Dioscorea, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. The research also aims to highlight the valuable bioactive compounds within Dioscorea and emphasize the need for further investigations into acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors to contribute to the discovery of novel pharmaceuticals.

MATERIALS AND METHODS

A search for available information on Dioscorea was conducted using scientific databases, including PubMed, ISI-WOS, Scopus, and Google Scholar, as well as recent academic publications from reputable publishers and other literature sources. The search was not limited by language and spanned the literature published between 1950 and 2022.

RESULTS

This article provides a comprehensive review of the Dioscorea genus, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. Extensive research has been conducted on this genus, resulting in the isolation and examination of over 1000 compounds, including steroids, terpenoids, and flavonoids, to determine their biological activities. These activities include anti-tumor, anti-inflammatory, immunomodulatory, neuroprotective, hypoglycemic, and hypolipidemic effects. However, some studies have indicated the potential toxicity of high doses of Dioscorea, highlighting the need for further investigations to assess the safety of this genus. Additionally, this review explores potential avenues for future research and discusses the challenges associated with a comprehensive understanding of the Dioscorea genus.

CONCLUSIONS

Based on the existing literature, it can be concluded that Dioscorea is a valuable source of bioactive compounds that have the potential to treat various disorders. Future research should prioritize the investigation of acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors. This review provides a comprehensive analysis of the Dioscorea genus, emphasizing its potential to enable a deeper exploration of the biological activity mechanisms of these plants and contribute to the discovery of novel pharmaceuticals.

Jujuboside B post-treatment attenuates PM2.5-induced lung injury in mice

Fine particulate matter (PM2.5) is an air pollutant that causes severe lung injury. We investigated the effects of Jujuboside B (JB), a component of Zizyphi Spinosi Semen, on lung toxicity caused by PM2.5, and we identified the mechanism of its protective effect. Lung injury in an animal model was induced by intratracheal administration of a PM2.5 suspension. After 2 days of PM2.5 pretreatment, mice were administered JB via the tail vein three times over a 2-day period. JB significantly reduced the histological lung damage as well as the lung wet/dry weight ratio. JB also considerably reduced PM2.5-induced autophagy dysfunction, apoptosis, inflammatory cytokine levels, and the number of PM2.5-induced lymphocytes in the bronchial alveolar fluid. We conclude that by regulating TLR2, 4-MyD88, and mTOR-autophagy pathways, JB exerts a protective effect on lung injury. Thus, JB can be used as a potential therapeutic agent for PM2.5-induced lung damage.

Extraction optimization, purification, and biological properties of polysaccharide from Chinese yam peel

In this study, the Chinese yam peel polysaccharide (CYPP) was obtained under the extraction conditions optimized by the Response Surface Methodology (RSM). Further biological properties of CYPP-1 purified from CYPP were also determined. The results indicated that the optimum extraction conditions were an extraction temperature of 90.5°C, a liquid-solid ratio of 28.0 ml/g, and an extraction time of 2.94 h, along with a yield of 8.81 ± 1.48%. CYPP-1 was identified as a kind of heteropolysaccharide mostly composed of glucose and galactose (59.4:1.0). The molecular weights were two main parts of 50.5 kDa (54.77%) and 4.4 kDa (21.02%), and the triple-helix conformation was not formed in CYPP-1. Besides, CYPP-1 showed good biological properties including in vitro antioxidant activity and immunomodulatory function on RAW264.7 cells, as well as favorable hypoglycemic effect. Overall, the high-value utilization of CYPP-1 reveals a broad application prospect in the industrial production of functional foods and pharmaceuticals. PRACTICAL APPLICATIONS: Yam peel, which is discarded in large quantities during postharvest processing, results in the production of tremendous by-products and is a great waste of resources. In this study, the yield of water-soluble polysaccharide from yam peel reached 8.81 ± 1.48%. Besides, the purified CYPP-1 exhibited excellent antioxidant activity, favorable immunomodulatory function, and hypoglycemic effect. The high productivity and bioactive effects are both great merits for Chinese yam peel polysaccharide as a promising candidate for foods and medicines industrial production.

Cirsilineol Treatment Attenuates PM2.5-Induced Lung Injury in Mice

Ultrafine particulate matter with less than 2.5 μm diameter (PM_2.5) is an air pollutant that causes severe lung damage. Currently, effective treatment and preventive methods for PM_2.5-induced lung damage are limited. Cirsilineol (CSL) is a small natural compound isolated from Artemisia vestita. In this study, the efficacy of CSL on PM_2.5-induced lung toxicity was tested, and its mechanism was identified. Lung injury was caused by intratracheal administration of PM_2.5 suspension in animal models. Two days after PM_2.5 pretreatment, CSL was injected via mouse tail vein for two days. The effects of CSL on PM_2.5-induced lung damage, autophagy, apoptosis, and pulmonary inflammation in a mouse model and their mechanisms were investigated. CSL significantly suppressed histological lung damage and lung wet/dry weight proportion. CSL also significantly reduced PM_2.5-induced autophagy dysfunction, apoptosis, lymphocyte suppression, and inflammatory cytokine levels in bronchoalveolar fluid (BALF). Furthermore, CSL increased mammalian target of rapamycin (mTOR) phosphorylation and significantly inhibited the expression of Toll-like receptors (TLR) 2 and 4, MyD88, and the autophagy proteins, Beclin1 and LC3II. Thus, CSL exerts protective effects on pulmonary damage by regulating mTOR and TLR2,4-myD88 autophagy pathways. Therefore, CSL can be used as an effective treatment for PM_2.5-induced lung damage.

Development and Validation of Quantitative Analysis Method for Phenanthrenes in Peels of the Dioscorea Genus

Phenanthrenes are bioactive phenolic compounds found in genus Dioscorea, in which they are distributed more in peel than in flesh. Recent studies on phenanthrenes from Dioscorea sp. peels have revealed the potential for valuable biomaterials. Herein, an analytical method using high-performance liquid chromatography (HPLC) for quantitation of bioactive phenanthrenes was developed and validated. The calibration curves were obtained using the phenanthrenes (1-3) previously isolated from Dioscorea batatas concentrations in the range of 0.625-20.00 μg/ml with a satisfactory coefficient of determination (R²) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) values of the isolated phenanthrenes ranged from 0.78-0.89 and 2.38-2.71 μg/ml, respectively. The intraday and interday precision ranged from 0.25-7.58%. The recoveries of the isolated phenanthrenes were from 95 to 100% at concentrations of 1.25, 2.5, and 5.0 μg/ml. Additionally, phenanthrenes (1-3) were found in all investigated peel extracts. Hence, the developed method was encouraging for the quantitative analysis of phenanthrenes in genus Dioscorea.

Effect of fungal indoor air pollutant 1-octen-3-ol on levels of reactive oxygen species and nitric oxide as well as dehydrogenases activities in drosophila melanogaster males

Fungal pollution of indoor environments contributes to several allergic symptoms and represents a public health problem. It is well-established that 1-octen-3-ol, also known as mushroom alcohol, is a fungal volatile organic compound (VOC) commonly found in damp indoor spaces and responsible for the typical musty odor. Previously it was reported that exposure to 1-octen-3-ol induced inflammations and disrupted mitochondrial morphology and bioenergetic rate in Drosophila melanogaster. The aim of this study was to examine the influence of 1-octen-3-ol on dehydrogenase activity, apoptotic biomarkers, levels of nitric oxide (NO) and reactive oxygen species (ROS), as well as antioxidant enzymes activities. D. melanogaster flies were exposed to an atmosphere containing 1-octen-3-ol (2.5 or ∞l/L) for 24 hr. Data demonstrated that 1-octen-3-ol decreased dehydrogenases activity and NO levels but increased ROS levels accompanied by stimulation of glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities without altering caspase 3/7 activation. These findings indicate that adverse mitochondrial activity effects following exposure of D. melanogaster to 1-octen-3-ol, a fungal VOC, may be attributed to oxidant stress. The underlying mechanisms involved in adverse consequences of indoor fungal exposure appear to be related to necrotic but not apoptotic mechanisms. The adverse consequences were sex-dependent with males displaying higher sensitivity to 1-octen-3-ol. Based upon on the fact that the fly genome shares nearly 75% of disease-related genes to human exposure to this fungus may explain the adverse human responses to mold especially for males.

Anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene isolated from Dioscorea batatas Decne partly through suppressing the p38 MAPK/NF-κB pathway in BV2 microglial cells

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Dioscorea batatas Decne (called Chinses yam) widely distributed in East Asian countries including China, Japan, Korea and Taiwan has long been used in oriental folk medicine owing to its tonic, antitussive, expectorant and anti-ulcerative effects. It has been reported to have anti-inflammatory, antioxidative, cholesterol-lowering, anticholinesterase, growth hormone-releasing, antifungal and immune cell-stimulating activities.

AIM OF THE STUDY

Neuroinflammation caused by activated microglia contributes to neuronal dysfunction and neurodegeneration. In the present study, the anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene (DHDMP), a phenanthrene compound isolated from Dioscorea batatas Decne, was examined in microglial and neuronal cells.

MATERIALS AND METHODS

A natural phenanthrene compound, DHDMP, was isolated from the peel of Dioscorea batatas Decne. The anti-neuroinflammatory capability of the compound was examined using the co-culture system of BV2 murine microglial and HT22 murine neuronal cell lines. The expression levels of inflammatory mediators and cytoprotective proteins in the cells were quantified by enzyme-linked immunosorbent assay and Western blot analysis.

RESULTS

DHDMP at the concentrations of ≤1 μg/mL did not exhibit a cytotoxic effect for BV2 and HT22 cells. Rather DHDMP effectively restored the growth rate of HT22 cells, which was reduced by co-culture with lipopolysaccharide (LPS)-treated BV2 cells. DHDMP significantly decreased the production of proinflammatory mediators, such as nitric oxide, tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 in BV2 cells. Moreover, DHDMP strongly inhibited the nuclear translocation of nuclear factor κB (NF-κB) and phosphorylation of p38 mitogen-activated protein kinase (MAPK) in BV2 cells. The compound did not affect the levels and phosphorylation of ERK and JNK. Concurrently, DHDMP increased the expression of heme oxygenase-1 (HO-1), an inducible cytoprotective enzyme, in HT22 cells.

CONCLUSIONS

Our findings indicate that DHDMP effectively dampened LPS-mediated inflammatory responses in BV2 microglial cells by suppressing transcriptional activity of NF-κB and its downstream mediators and contributed to HT22 neuronal cell survival. This study provides insight into the therapeutic potential of DHDMP for inflammation-related neurological diseases.

Botanical formulation, TADIOS, alleviates lipopolysaccharide (LPS)-Induced acute lung injury in mice via modulation of the Nrf2-HO-1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

TADIOS is an herbal formulation prepared from a mixture of Taraxacum officinale (L.) Weber ex F.H.Wigg, Dioscorea batatas Decaisne and Schizonepeta tenuifolia (Benth.) Briquet. These plants have traditionally been used in Asia to treat a variety of respiratory diseases. A bulk of literature on traditional Korean medicine describe their activities and functions for respiratory problems. Therefore, we hypothesized that the combination of these plants might be effective in alleviating respiratory symptoms.

AIM OF THE STUDY

In this study, we investigated whether TADIOS ameliorates LPS-induced acute lung injury via regulation of the Nrf2-HO-1 signaling pathway.

MATERIALS AND METHODS

The LPS-induced acute lung injury mouse model was used to determine the anti-inflammatory and anti-oxidative stress effects of TADIOS. The amount of marker compounds contained in TADIOS was quantified using high-performance liquid chromatography (HPLC) analysis. The protein level of pro-inflammatory cytokines in culture supernatant was measured by ELISA. Changes in the RNA level of pro-inflammatory cytokines in mice lungs and RAW264.7 cells were measured by quantitative RT-PCR. The relative amounts of reactive oxygen species (ROS) were measured by DCF-DA assay. Western blot analysis was used to evaluate expression of cellular proteins. Effects of TADIOS on antioxidant responsive elements (AREs) were determined by luciferase assay. The severity of acute lung injury was evaluated by Hematoxylin & Eosin (H&E) staining. To test the effects of TADIOS on LPS-induced oxidative stress, myeloperoxidase (MPO) activity and the total antioxidant capacity were measured.

RESULTS

TADIOS was prepared by extraction of a blend of these three plants by ethanol, and quality control was performed through quantification of marker compounds by HPLC and measurement of bioactivities using cell-based bioassays. In the murine macrophage cell line RAW264.7, TADIOS effectively suppressed the production of pro-inflammatory cytokines such as IL-6 and IL-1β, and also ROS induced by LPS. When RAW264.7 cells were transfected with a luciferase reporter plasmid containing nucleotide sequences for AREs, TADIOS treatment increased the level of relative luciferase units in a dose-dependent manner. In the LPS-induced acute lung injury mouse model, orally administered TADIOS alleviated lung damage and neutrophil infiltration induced by LPS. Consistent with the in vitro data, treatment with TADIOS inhibited the LPS-mediated expression of pro-inflammatory cytokines and oxidative stress, and activated the Nrf2-HO-1 axis.

CONCLUSION

Our data suggest the potential for TADIOS to be developed as a safe and effective therapeutics for the treatment of acute respiratory distress syndrome.

The Protective Effects of Shengmai Formula Against Myocardial Injury Induced by Ultrafine Particulate Matter Exposure and Myocardial Ischemia are Mediated by the PI3K/AKT/p38 MAPK/Nrf2 Pathway

Background and Purpose: Ultrafine particulate matter (UFPM) induces oxidative stress (OS) and is considered to be a risk factor of myocardial ischemia (MI). Shengmai formula (SMF) is a traditional Chinese medicine with antioxidant properties and has been used to treat cardiovascular diseases for a long time. The aim of this study was to explore the protective role of SMF and the mechanism by which it prevents myocardial injury in UFPM-exposed rats with MI. Methods: An MI rat model was established. Animals were randomly divided into five groups: sham, UFPM + MI, SMF (1.08 mg/kg⋅d) + UFPM + MI, SMF (2.16 mg/kg⋅d) + UFPM + MI, and SMF (4.32 mg/kg⋅d) + UFPM + MI. SMF or saline was administrated 7 days before UFPM instillation (100 μg/kg), followed by 24 h of ischemia. Physiological and biochemical parameters were measured, and histopathological examinations were conducted to evaluate myocardial damage. We also explored the potential mechanism of the protective role of SMF using a system pharmacology approach and an in vitro myoblast cell model with small molecule inhibitors. Results: UFPM produced myocardial injuries on myocardial infarct size; serum levels of LDH, CK-MB, and cardiac troponin; and OS responses in the rats with MI. Pretreatment with SMF significantly attenuated these damages via reversing the biomarkers. SMF also improved histopathology induced by UFPM and significantly altered the PI3K/AKT/MAPK and OS signaling pathways. The expression patterns of Cat, Gstk1, and Cyba in the UFPM model group were reversed in the SMF-treated group. In in vitro studies, SMF attenuated UFPM-induced reactive oxygen species production, mitochondrial damage, and OS responses. The PI3K/AKT/p38 MAPK/Nrf2 pathway was significantly changed in the SMF group compared with that in the UFPM group, whereas opposite results were obtained for pathway inhibition. Conclusion: These findings indicate that SMF prevents OS responses and exerts beneficial effects against myocardial injury induced by UFPM + MI in rats. Furthermore, the PI3K/AKT/p38 MAPK/Nrf2 signaling pathway might be involved in the protective effects of SMF.

Inhibitory functions of cardamonin against particulate matter-induced lung injury through TLR2,4-mTOR-autophagy pathways

Particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM_2.5) is a form of air pollutant that causes significant lung damage when inhaled. Cardamonin, a flavone found in Alpinia katsumadai Heyata seeds, has been reported to have anti-inflammatory and anticoagulative activity. The aim of this study was to determine the protective effects of cardamonin on PM_2.5-induced lung injury. Mice were treated with cardamonin via tail-vein injection 30 min after the intratracheal instillation of PM_2.5. The results showed that cardamonin markedly reduced the pathological lung injury, lung wet/dry weight ratio, and hyperpermeability caused by PM_2.5. Cardamonin also significantly inhibited PM_2.5-induced myeloperoxidase (MPO) activity in lung tissue, decreased the levels of PM_2.5-induced inflammatory cytokines and effectively attenuated PM_2.5-induced increases in the number of lymphocytes in the bronchoalveolar lavage fluid (BALF). And, cardamonin increased the phosphorylation of mammalian target of rapamycin (mTOR) and dramatically suppressed the PM_2.5-stimulated expression of toll-like receptor 2 and 4 (TLR 2,4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that cardamonin has a critical anti-inflammatory effect due to its ability to regulate both the TLR2,4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against PM_2.5-induced lung injury.

Inhibitory functions of maslinic acid on particulate matter-induced lung injury through TLR4-mTOR-autophagy pathways

Particulate matter (PM), the collection of all liquid and solid particles suspended in air, includes both organic and inorganic particles, many of which are health-hazards. PM particles with a diameter equal to or less than 2.5 μm (PM_2.5) is a form of air pollutant that causes significant lung damage when inhaled. Maslinic acid (MA) prevents oxidative stress and pro-inflammatory cytokine generation, but there is little information available regarding its role in PM-induced lung injury. Therefore, the purpose of this study was to determine the protective activity of MA against PM_2.5-induced lung injury. The mice were divided into seven groups (n = 10 each): a mock control group, an MA control (0.8 mg/kg mouse body weight) group, an opted PM_2.5 produced from diesel (10 mg/kg mouse body weight) group, a diesel PM_2.5+MA (0.2, 0.4, 0.6, and 0.8 mg/kg mouse body weight) groups. Mice were treated with MA via tail-vein injection 30 min after the intratracheal instillation of a diesel PM_2.5. Changes in the wet/dry weight ratio of the lung tissue, total protein/total cell and lymphocyte counts, inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), vascular permeability, and histology were monitored in diesel PM_2.5-treated mice. The results showed that MA reduced pathological lung injury, the wet/dry weight ratio of the lung tissue, and hyperpermeability caused by diesel PM_2.5. MA also inhibited diesel PM_2.5-induced myeloperoxidase (MPO) activity in the lung tissue, decreased the levels of diesel PM_2.5-induced inflammatory cytokines, including tumor necrosis factor (TNF)-α and interleukin (IL)-1β, reduced nitric oxide (NO) and total protein in the BALF, and effectively attenuated diesel PM_2.5-induced increases in the number of lymphocytes in the BALF. In addition, MA increased the protein phosphorylation of the mammalian target of rapamycin (mTOR) and dramatically suppressed diesel PM_2.5-stimulated expression of toll-like receptor 4 (TLR4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that MA has a critical anti-inflammatory effect due to its ability to regulate both the TLR4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against diesel PM_2.5-induced lung injury.

Biapenem as a Novel Insight into Drug Repositioning against Particulate Matter-Induced Lung Injury

The screening of biologically active chemical compound libraries can be an efficient way to reposition Food and Drug Adminstration (FDA)-approved drugs or to discover new therapies for human diseases. Particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM_2.5) is a form of air pollutant that causes significant lung damage when inhaled. This study illustrates drug repositioning with biapenem (BIPM) for the modulation of PM-induced lung injury. Biapenem was used for the treatment of severe infections. Mice were treated with BIPM via tail-vein injection after the intratracheal instillation of PM_2.5. Alterations in the lung wet/dry weight, total protein/total cell count and lymphocyte count, inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), vascular permeability, and histology were monitored in the PM_2.5-treated mice. BIPM effectively reduced the pathological lung injury, lung wet/dry weight ratio, and hyperpermeability caused by PM_2.5. Enhanced myeloperoxidase (MPO) activity by PM_2.5 in the pulmonary tissue was inhibited by BIPM. Moreover, increased levels of inflammatory cytokines and total protein by PM_2.5 in the BALF were also decreased by BIPM treatment. In addition, BIPM markedly suppressed PM_2.5-induced increases in the number of lymphocytes in the BALF. Additionally, the activity of mammalian target of rapamycin (mTOR) was increased by BIPM. Administration of PM_2.5 increased the expression levels of toll-like receptor 4 (TLR4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1, which were suppressed by BIPM. In conclusion, these findings indicate that BIPM has a critical anti-inflammatory effect due to its ability to regulate both the TLR4-MyD88 and mTOR-autophagy pathways, and may thus be a potential therapeutic agent against diesel PM_2.5-induced pulmonary injury.

Quantitative Analysis of Bioactive Phenanthrenes in Dioscorea batatas Decne Peel, a Discarded Biomass from Postharvest Processing

Dioscorea batatas Decne (Chinese yam) has been widely cultivated in East Asia for the purposes of food and medicinal uses for centuries. Along with its high nutritional value, the medicinal value of D. batatas has been extensively investigated in association with phytochemicals such as allantoin, flavonoids, saponins and phenanthrenes. Phenanthrenes are especially considered the standard marker chemicals of the Chinese yam for their potent bioactivity and availability of analysis with conventional high performance liquid chromatography with ultraviolet detection (HPLC-UV) methods. In order to investigate how much the contents of phenanthrenes are in the actual food products provided for consumers, D. batatas tuber was peeled and separated into its peel and flesh as in the conventional processing method. A quantitative analysis using the HPLC-UV method revealed that phenanthrenes are concentrically present in the D. batatas peel, while phenanthrenes are present in the flesh under the limit of detection. The difference in the contents of phenanthrenes is estimated to have arisen the considerable difference of antioxidant potential between the peel and the flesh. The results from this study suggest the high value of the discarded biomass of the Chinese yam peel and the necessity for the utilization of the Chinese yam peel.