Anti-allergic substances from the rhizomes of Dioscorea membranacea

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.

Diastereoselective Formal [5+2] Cycloaddition of Diazo Arylidene Succinimides-Derived Rhodium Carbenes and Aldehydes: A Route to 2-Benzoxepines

We report on a facile method for the preparation of 2-benzoxepine derivatives as a result of Rh(II)-catalyzed decomposition of diazo arylidene succinimides in the presence of aldehydes. The process is thought to involve the formation of styryl carbonyl ylide which undergoes 1,7-electrocyclization and subsequent 1,5-hydrogen shift. In some cases, the competition of the target reaction and [3+2] dipolar cycloaddition of the intermediate carbonyl ylide to another molecule of diazo substrate was observed. Generally, the desired 2-benzoxepines were isolated in good to high yields and high diastereoselectivity. The developed original approach toward a 2-benzoxepine core via formal [5+2] cycloaddition of styryl carbenoids and aldehydes significantly expands the arsenal of synthetic methods for producing this scaffold.

Therapeutic efficacy of a Dioscorea membranacea extract in a rat model of hepatocellular carcinoma: Histopathological aspects

Hepatocellular carcinoma (HCC) is most common in adults and has a high mortality rate because of a lack of effective treatment options. We investigated the effect of a medicinal plant as a potential source of drugs against HCC. The rhizomes of Dioscorea membranacea Pierre (DM), Hua-Khao-Yen in Thai, are commonly used as ingredients for alternative treatment of cancer in Thailand. In this study, the anticancer effects of DM extract in HCC-bearing rats were evaluated with respect to gross morphology, histopathology, and leakage of liver enzymes. In untreated HCCs, typical features of liver cancer, including hepatic nodules, thick-cell cords, and pseudoglandular cell arrangements, were observed. In addition, the HCCs showed abnormal reticulin patterns and a high glypican3 expression. In HCC-bearing rats treated with DM the cancer areas and reticulin expression were significantly reduced compared to the untreated group (p < 0.01). Sorafenib, the standard drug to treat HCC, reduced the cancer area further, but increased leakage of liver enzymes and decreased serum albumin concentration, indicating liver toxicity. These findings suggest that DM has an anticancer effect on HCCs in an animal model in vivo with potentially less severe side effects than sorafenib. Therefore, further studies of DM’s mechanism of action in HCC should be carried out.

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DM exerted a mitigating effect on histopathology and membrane damage of HCC in rats.

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Its effect was similar to that of the standard drug sorafenib.

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It reduced the volume of cancer nodules without the serious hepatotoxic side effects seen after SF treatment.

Pharmacologic activities of phytosteroids in inflammatory diseases: Mechanism of action and therapeutic potentials

Natural products and their derivatives are known to be useful for treating numerous diseases since ancient times. Because of their high therapeutic potentials, the use of different medicinal plants is possible to treat varied inflammation-mediated chronic diseases. Among natural products, phytosteroids have emerged as promising compounds mostly because they have diverse pharmacological activities. Currently, available medications exert numerous systemic toxicities, including hypertension, immune suppression, osteoporosis, and metabolic abnormalities. Thus, further research on phytosteroids to subside these complications is of significant importance. In this study, the information on phytosteroids, their types, and actions against inflammation, and allergic complications was collected by a systematic survey of literature on several scientific search engines. The literature review suggested that phytosteroids exhibit antiinflammatory action via different modes through transrepression or selective COX-2 enzymes. Also, in silico ADMET analysis was carried out on available phytosteroids to uncover their pharmacokinetic properties. Our analysis has shown that eight compounds: withaferin A, stigmasterol, β-sitosterol, guggulsterone, diosgenin, sarsasapogenin, physalin A, and dioscin, -isolated from medicinal plants show similar pharmacokinetic properties as compared to dexamethasone, commercially available glucocorticoid. These phytosteroids could be useful for the treatment of inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel diseases, multiple sclerosis, asthma, and cardiovascular diseases. Thus, systematic research is required to explore potent phytosteroids with lesser side effects, which might substitute the current medications.

Improvement of dioscorealide B production by elicitation in shoot cultures of Dioscorea membranacea Pierre ex Prain & Burkill

Dioscorealide B is an important secondary metabolite isolated from Dioscorea membranacea Pierre ex Prain & Burkill. The effect on secondary metabolite content of different concentrations of two elicitors [jasmonic acid (JA) and salicylic acid (SA)], and of medium status and JA exposure period were investigated. In the JA and SA concentration experiment, 6-week-old shoots were cultured on MS medium supplemented with 8.87 µM BA (6-benzyladenine) in combination with 100-500 µM JA or 50-200 µM SA for 3 weeks. MS medium supplemented only with 8.87 µM BA was used as a control. The highest dioscorealide B content was recorded in the 100 µM JA shoots. To determine the optimal medium status and JA exposure period, shoots were cultured on solid and in liquid MS media supplemented with 8.87 µM BA and 100 µM JA for 2, 3, 4 and 5 weeks. No interaction was found between the medium status and the elicitor exposure period in the dioscorealide B production. Shoots cultured on the solid MS medium supplemented with 100 µM JA had a higher dioscorealide B content (0.57 ± 0.35% w/w) than those cultured in liquid medium (0.36 ± 0.40% w/w) and 5-week JA exposure produced the highest dioscorealide B content of 1.05 ± 0.15% (w/w).

In vitro anti-allergic activity of Moringa oleifera Lam. extracts and their isolated compounds

Background

Moringa oleifera Lam. is a commonly used plant in herbal medicine and has various reported bioactivities such as antioxidant, antimicrobial, anticancer and antidiabetes. It is rich in nutrients and polyphenols. The plant also has been traditionally used for alleviating allergic conditions. This study was aimed to examine the anti-allergic activity of M. oleifera extracts and its isolated compounds.

Method

M. oleifera leaves, seeds and pods were extracted with 80% of ethanol. Individual compounds were isolated using a column chromatographic technique and elucidated based on the nuclear magnetic resonance (NMR) and electrospray ionisation mass spectrometry (ESIMS) spectral data. The anti-allergic activity of the extracts, isolated compounds and ketotifen fumarate as a positive control was evaluated using rat basophilic leukaemia (RBL-2H3) cells for early and late phases of allergic reactions. The early phase was determined based on the inhibition of beta-hexosaminidase and histamine release; while the late phase was based on the inhibition of interleukin (IL-4) and tumour necrosis factor (TNF-α) release.

Results

Two new compounds; ethyl-(E)–undec-6-enoate (1) and 3,5,6-trihydroxy-2-(2,3,4,5,6-pentahydroxyphenyl)-4H-chromen-4-one (2) together with six known compounds; quercetin (3), kaempferol (4), β-sitosterol-3-O-glucoside (5), oleic acid (6), glucomoringin (7), 2,3,4-trihydroxybenzaldehyde (8) and stigmasterol (9) were isolated from M. oleifera extracts. All extracts and the isolated compounds inhibited mast cell degranulation by inhibiting beta-hexosaminidase and histamine release, as well as the release of IL-4 and TNF-α at varying levels compared with ketotifen fumarate.

Conclusion

The study suggested that M. oleifera and its isolated compounds potentially have an anti-allergic activity by inhibiting both early and late phases of allergic reactions.

Dioscorea nipponica Makino: a systematic review on its ethnobotany, phytochemical and pharmacological profiles

Dioscorea nipponica Makino is a perennial twining herbs belonging to the family Dioscoreaceae, which is mainly distributed in the northeastern, northern, eastern and central regions of China. Traditionally, the rhizome of this herb has been commonly used by Miao and Meng ethnic groups of China to treat rheumatoid arthritis, pain in the legs and lumbar area, Kashin Beck disease, bruises, sprains, chronic bronchitis, cough and asthma. Modern pharmacological studies have discovered that this herb possesses anti-tumor, anti-inflammatory, anti-diuretic, analgesic, anti-tussive, panting-calming and phlegm-dispelling activities, along with enhancing immune function and improving cardiovascular health. In recent years, both fat-soluble and water-soluble steroidal saponins were isolated from the rhizomes of D. nipponica using silica gel column chromatography, thin layer chromatography and high performance liquid chromatography methods. Saponin and sapogenins are mainly responsible for most of the pharmacological effects of this plant. Further, the chemical components of the aboveground parts contain more than 10 kinds of phenanthrene derivatives. The present review summarizes the knowledge concerning the geographical distribution, chemical composition, pharmacological effects, toxicology studies and clinical applications of D. nipponica.

Soluble N-Ethylmaleimide-Sensitive Factor Attachment Protein Receptor-Derived Peptides for Regulation of Mast Cell Degranulation

Vesicle-associated V-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and target membrane-associated T-SNAREs (syntaxin 4 and SNAP-23) assemble into a core trans-SNARE complex that mediates membrane fusion during mast cell degranulation. This complex plays pivotal roles at various stages of exocytosis from the initial priming step to fusion pore opening and expansion, finally resulting in the release of the vesicle contents. In this study, peptides with the sequences of various SNARE motifs were investigated for their potential inhibitory effects against SNARE complex formation and mast cell degranulation. The peptides with the sequences of the N-terminal regions of vesicle-associated membrane protein 2 (VAMP2) and VAMP8 were found to reduce mast cell degranulation by inhibiting SNARE complex formation. The fusion of protein transduction domains to the N-terminal of each peptide enabled the internalization of the fusion peptides into the cells equally as efficiently as cell permeabilization by streptolysin-O without any loss of their inhibitory activities. Distinct subsets of mast cell granules could be selectively regulated by the N-terminal-mimicking peptides derived from VAMP2 and VAMP8, and they effectively decreased the symptoms of atopic dermatitis in mouse models. These results suggest that the cell membrane fusion machinery may represent a therapeutic target for atopic dermatitis.

A novel steroid and cytotoxic constituents from Dioscorea membranacea Pierre against hepatocellular carcinoma and cholangiocarcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizomes of Dioscorea membrancea Pierre have been used in Thai traditional medicine as an ingredient formula for liver cancer and cholangiocarcinoma treatment.

AIM OF THE STUDY

To investigate the cytotoxic activity of ethanolic extract and constituents of D. membrancea to support its traditional use.

MATERIALS AND METHODS

The SRB assay was used to determine the cytotoxic activity against hepatocellular carcinoma (HepG2), cholangiocarcinoma (KKU-M156) cells and one normal human keratinocyte immortal cells (HaCaT) with its ethanolic extract and isolated compounds. Bioassay guided isolation was used for isolating cytotoxic compounds.

RESULTS

The ethanolic extract of D. membranacea rhizome showed weak cytotoxic against KKU-M156 and HepG2 (IC₅₀ at 72h exposure=30.49±0.82 and 38.97±2.04µg/mL respectively). A new steroid [epipanthogenin B (1)], a known steroid [panthogenin B (2)], two napthofuranoxepins [dioscorealide A (3) and dioscorealide B (4)], phenanthraquinone [dioscoreanone (5)] and two phenanthrene [5,6-dihydroxy-2,4-dimethoxy-9,10-dihydrophenanthrene (6) and 2,5,6-trihydroxy-3,4-dimethoxy, 9, 10-dihydrophenanthrene (7)] were isolated from active chloroform fraction. Compound 4 showed the highest cytotoxicity against HepG2 (IC₅₀ at 72h exposure=2.87±0.21µM) and KKU-M156 (IC₅₀ at 72h exposure=1.67±0.10µM) and less toxicity against normal cell line (HaCaT) (IC₅₀ at 72h exposure>100µM). Compound 5 showed selective cytotoxic activity against KKU-M156 (IC₅₀ at 72h exposure=3.46±0.11µM). Compounds 6 and 7 showed weak cytotoxic activity against HepG2 (IC₅₀ at 72h exposure=24.96±2.32 and 51.31±3.52µM). Compounds (1-3) showed no cytotoxic activity against HepG2 and KKU-M156 cell lines (IC₅₀ at 72 h exposure>100µM).

CONCLUSION

Seven compounds were isolated from active chloroform fraction of the ethanolic extract of D. membranacea rhizomes. Only dioscorealide B (4) might be served as a good anticancer agent for liver cancer and cholangiocarcinoma cancer because it can kill cancer cell but not toxic on normal cell. This research support Thai traditional medicine use of D. membranacea for liver cancer and cholangiocarcinoma cancer treatment.

Inhibitory Effect on β -Hexosaminidase Release from RBL-2H3 Cells of Extracts and Some Pure Constituents of Benchalokawichian, a Thai Herbal Remedy, Used for Allergic Disorders

Introduction. Benchalokawichian (BCW), a Thai traditional herbal formulation, has long been used as antipyretic and to treat skin disorders. It comprises roots from five herbs: Ficus racemosa, Capparis micracantha, Clerodendrum petasites, Harrisonia perforata, and Tiliacora triandra. This polyherbal remedy has recently been included in the Thailand National List of Essential Medicines (Herbal Products list). Methodology. A Bioassay-guided fractionation technique was used to evaluate antiallergy activities of crude extracts, and those obtained by the multistep column chromatography isolation of pure compounds. Inhibitory effect on the release of β-hexosaminidase from RBL-2H3 cells was used to determine antiallergic activity. Results. Two pure compounds from BCW formulation showed higher antiallergic activity than crude or semipure extracts. Pectolinarigenin showed the highest antiallergic activity, followed by O-methylalloptaeroxylin, with IC50 values of 6.3 μg/mL and 14.16 μg/mL, respectively. Moreover, the highest activities of pure compounds were significantly higher than chlorpheniramine (16.2 μg/mL). Conclusions. This study provides some support for the use of BCW in reducing itching and treatment of other skin allergic disorders. The two isolated constituents exhibited high antiallergic activity and it is necessary to determine their mechanism of action. Further phytochemical and safety studies of pure compounds are required before development of these as antiallergy commercial remedies.

Immunomodulatory activity of Dioscorea membranacea Pierre rhizomes and of its main active constituent Dioscorealide B

BACKGROUND

The rhizomes of Dioscorea membranacea Pierre, also called Hua-Khao-Yen by Thai name, are used as ingredients in many Thai traditional medicines for the alternative or complementary treatment of cancer and AIDs. Preliminary in vitro studies have indicated that D. membranacea extracts exhibited high cytotoxic activity with several cancer cell lines, but the underlining mechanisms are far from clear. The aims of this study were to investigate the effects of ethanolic and aqueous crude extracts from D. membranacea Pierre, and pure compound from D. membranacea Pierre, Dioscorealide B, on natural killer cells activity and on lymphocyte proliferation.

METHODS

Immunomodulatory activity was investigated using PBMCs from healthy donors. NK cells activity was performed by the chromium release assay using PBMCs as effector cells, and K562 cells line labelled with chromium as target cells. Lymphocyte proliferation was determined by 3H-thymidine uptake. The degree of activation was expressed as the stimulation index.

RESULTS

The crude ethanolic extracts of D. membranacea Pierre significantly stimulated NK cells activity against K562 cells line at lower concentrations of 10 and 100 ng/ml, but not at higher concentrations. The ethanolic extracts showed no observable effect on lymphocyte proliferation. The crude water extracts significantly increased NK cell activity at concentrations of 10 ng/ml, 100 ng/ml, 1 μg/ml, 10 μg/ml and 100 μg/ml, and also activated lymphocyte proliferation at concentration of 1 ng/ml, 10 ng/ml, 100 ng/ml, 1 μg/ml, 5 μg/ml, 10 μg/ml and 100 μg/ml. However, Dioscorealide B had no significant effect at lower concentrations (0-1 μg/ml and 0-0.1 μg/ml, respectively) on NK cell activity and lymphocyte proliferation. In fact higher concentrations (>10 μg/ml and >0.5 μg/ml) of Dioscorealide B cause a significant decrease in NK cell activity and lymphocyte proliferation.

CONCLUSIONS

D. membranacea Pierre stimulated NK cells activity and lymphocyte proliferation, but Dioscorealide B either had no effect, and at higher concentrations decreased NK cell activity and lymphocyte proliferation. Our results suggest that both extracts of D. membranacea Pierre significantly increases immune function, but the underlining mechanism is not clearly understood.

Modulation of basophils' degranulation and allergy-related enzymes by monomeric and dimeric naphthoquinones

Allergic disorders are characterized by an abnormal immune response towards non-infectious substances, being associated with life quality reduction and potential life-threatening reactions. The increasing prevalence of allergic disorders demands for new and effective anti-allergic treatments. Here we test the anti-allergic potential of monomeric (juglone, menadione, naphthazarin, plumbagin) and dimeric (diospyrin and diosquinone) naphthoquinones. Inhibition of RBL-2H3 rat basophils' degranulation by naphthoquinones was assessed using two complementary stimuli: IgE/antigen and calcium ionophore A23187. Additionally, we tested for the inhibition of leukotrienes production in IgE/antigen-stimulated cells, and studied hyaluronidase and lipoxidase inhibition by naphthoquinones in cell-free assays. Naphthazarin (0.1 µM) decreased degranulation induced by IgE/antigen but not A23187, suggesting a mechanism upstream of the calcium increase, unlike diospyrin (10 µM) that reduced degranulation in A23187-stimulated cells. Naphthoquinones were weak hyaluronidase inhibitors, but all inhibited soybean lipoxidase with the most lipophilic diospyrin, diosquinone and menadione being the most potent, thus suggesting a mechanism of competition with natural lipophilic substrates. Menadione was the only naphthoquinone reducing leukotriene C₄ production, with a maximal effect at 5 µM. This work expands the current knowledge on the biological properties of naphthoquinones, highlighting naphthazarin, diospyrin and menadione as potential lead compounds for structural modification in the process of improving and developing novel anti-allergic drugs.

Polyphenols differentially inhibit degranulation of distinct subsets of vesicles in mast cells by specific interaction with granule-type-dependent SNARE complexes

Anti-allergic effects of dietary polyphenols were extensively studied in numerous allergic disease models, but the molecular mechanisms of anti-allergic effects by polyphenols remain poorly understood. In the present study, we show that the release of granular cargo molecules, contained in distinct subsets of granules of mast cells, is specifically mediated by two sets of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, and that various polyphenols differentially inhibit the formation of those SNARE complexes. Expression analysis of RBL-2H3 cells for 11 SNARE genes and a lipid mixing assay of 24 possible combinations of reconstituted SNAREs indicated that the only two active SNARE complexes involved in mast cell degranulation are Syn (syntaxin) 4/SNAP (23 kDa synaptosome-associated protein)-23/VAMP (vesicle-associated membrane protein) 2 and Syn4/SNAP-23/VAMP8. Various polyphenols selectively or commonly interfered with ternary complex formation of these two SNARE complexes, thereby stopping membrane fusion between granules and plasma membrane. This led to the differential effect of polyphenols on degranulation of three distinct subsets of granules. These results suggest the possibility that formation of a variety of SNARE complexes in numerous cell types is controlled by polyphenols which, in turn, might regulate corresponding membrane trafficking.

Molecular mechanism underlying anti-inflammatory and anti-allergic activities of phytochemicals: an update

The resort worldwide to edible medicinal plants for medical care has increased significantly during the last few years. Currently, there is a renewed interest in the search for new phytochemicals that could be developed as useful anti-inflammatory and anti-allergic agents to reduce the risk of many diseases. The activation of nuclear transcription factor-kappa B (NF-κB) has now been linked to a variety of inflammatory diseases, while data from numerous studies underline the importance of phytochemicals in inhibiting the pathway that activates this transcription factor. Moreover, the incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. Thus, a good number of plant products with anti-inflammatory and anti-allergic activity have been documented, but very few of these compounds have reached clinical use and there is scant scientific evidence that could explain their mode of action. Therefore, this paper intends to review the most salient recent reports on the anti-inflammatory and anti-allergic properties of phytochemicals and the molecular mechanisms underlying these properties.

Evaluation of antiallergic and anti-anaphylactic activity of ethanolic extract of Sanseveiria trifasciata leaves (EEST) in rodents

AIM OF THE STUDY

The leaves and rhizomes of Sansevieria trifasciata are used in folk medicine for treating bronchitis, asthma, cough, snake bite and insect bite etc. The ethanolic extract elicited analgesic, anti-inflammatory and antipyretic activity. Hence, it was decided to study the antiallergic activity of ethanolic extract of S. trifasciata (EEST) on various animal models as well as in vitro conditions, and also to understand possible mechanism of action.

MATERIALS AND METHODS

Ethanolic extract of S. trifasciata leaves (EEST) were prepared by cold maceration followed by concentration and evaporation under reduced pressure on a rotary evaporator to obtain semisolid mass. The various phytoconstituents were analyzed. The acute toxicity study of EEST was carried out in mice. The antiallergic and anaphylactic activities were evaluated using animal models viz. milk induced eosinophilia and leukocytosis, compound 48/80 induced mast cell degranulation, active and passive cutaneous anaphylaxis and histamine induced pedal edema. In addition, EEST effect on Shultz-Dale reaction in sensitized guinea pig ileum in ex vivo and antioxidant activity by free radical scavenging by DPPH method (in vitro) were also studied.

RESULTS

EEST treatment at 100mg/kg and 200mg/kg p.o inhibited (a) milk-induced increased eosinophilia, leukocytosis, monocytes and neutrophils. (b) Prevented passive cutaneous and active anaphylactoid reactions. (c) Prevented compound 48/80 induced degranulation of sensitized mesenteric mast cells. (d) Inhibited histamine induced pedal edema formation significantly. EEST pretreatment inhibited Shultz-Dale reaction in guinea pig ileum and also elicited potent antioxidant activity.

CONCLUSION

Experimental findings demonstrate promising antiallergic and anti-anaphylactic activity of EEST and also elicited potent antioxidant activity. The antiallergic and anti-anphylactic activity might be due to inhibition of release of chemical mediators from mast cells largely by phytoconstituents like steroidal saponins, triterpenoids and flavonoids present in EEST.

Inhibitory effects of adlay bran (Coix lachryma-jobi L. var. ma-yuen Stapf) on chemical mediator release and cytokine production in rat basophilic leukemia cells

ETHNOPHARMACOLOGICAL RELEVANCE

Adlay (Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf) has long been used in China to treat rheumatism.

AIM OF THE STUDY

We investigated the anti-allergic effects of adlay bran on rat basophilic leukemia (RBL)-2H3 cells.

MATERIALS AND METHODS

To evaluate the anti-allergic effects of adlay bran, the release of histamines and cytokines were measured using ELISA. To explore the mechanism of these effects, the protein expression levels were determined using western blotting.

RESULTS

A 40.8μg/mL concentration of the ethyl acetate fraction of the ethanolic extracts of adlay bran (ABE-EtOAc) effectively inhibited mast cell degranulation. The 40-100% EtOAc/Hex subfractions of ABE-EtOAc inhibited histamine release with an IC(50) of 71-87μg/mL. Moreover, the ABE-EtOAc subfractions suppressed the secretion of interleukin (IL)-4, IL-6 and tumor necrosis factor-α in the RBL-2H3 cells, indicating that adlay bran can inhibit cytokine secretion in the late phase of the allergic reaction. In addition, adlay bran reduced the intracellular production of reactive oxygen species, inhibited the phosphorylation of Akt and decreased the expression of protein kinase C. Furthermore, six phenolic acids and one flavone were isolated. Of these compounds, luteolin showed the most potent inhibitory activity (IC(50)=1.5μg/mL).

CONCLUSION

Adlay bran extract reduced the release of histamines and cytokines and suppressed the production of Akt. These combined effects influenced the signal transduction in RBL-2H3 cells, thereby revealing the mechanisms of the anti-allergic effects of adlay.

A review on pharmacological and analytical aspects of diosgenin: a concise report

Diosgenin is a steroidal sapogenin found in plants such as Dioscorea nipponoca, Solanum incanum, Solanum xanthocarpum and Trigonella foenum graecum. Diosgenin, biologically active phytochemicals have been used for the treatment of various types of disorder such as leukemia, inflammation, hypercholesterolemia and cancer. It is also able to prevent bone loss to the same extent as that of oestrogen. It is a typical initial intermediate for synthesis of steroidal compounds, oral contraceptives and sex hormones. Dioscorea, Costus and Trigonella are mainly used for the production of diosgenin. On the basis of literature survey it divulges that diosgenin has very impressive pharmacological profile and could be used as a medicine for the treatment of different types of disorders in the future. Thus, the present work aims to provide collective information in concern with its pharmacological activity and phytoanalytical techniques. This review will be beneficial to researches for the development of an alternative method for the treatment of innumerable diseases from diosgenin.

Mast cell-dependent allergic responses are inhibited by ethanolic extract of adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) testa

Allergy is an immune dysfunction caused by degranulation from mast cells in the early phase and cytokine secretion in the late phase of the cell. The purpose of this study was to investigate the effects of adlay (Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf) testa against beta-hexosaminidase release as a marker of degranulation in rat basophilic leukemia (RBL)-2H3 cells. The ethyl acetate fraction from ethanolic extracts of adlay testa (ATE-EtOAc) exhibited potent inhibitory activity that suppressed degranulation from RBL-2H3 cells stimulated by 1 microM A23187. The 20%-80% EtOAc/Hex subfractions of ATE-EtOAc significantly inhibited histamine release with a IC(50) of 75-100 microg/mL. In addition, the ATE-EtOAc subfractions suppressed interleukin (IL)-4, IL-6, and tumor necrosis factor-alpha secretion in RBL-2H3 cells, indicating that adlay testa were able to inhibit cytokine secretion. In order to explore the inhibitory mechanism of adlay testa in mast cell degranulation, we examined the activation of intracellular signaling molecules. Adlay testa inhibited the phosphorylation ERK expression. Furthermore, the two major active compounds, 4-hydroxyacetophenone and p-coumaric acid, were isolated from the ATE-EtOAc subfractions. These results suggest that ATE had an inhibitory effect on allergic response via the ERK signaling transduction in RBL-2H3 cells.

Anti-allergic activity of principles from the roots and heartwood of Caesalpinia sappan on antigen-induced beta-hexosaminidase release

The dichloromethane extract of the roots and heartwood of Caesalpinia sappan exhibited potent inhibitory activity against beta-hexosaminidase release as marker of degranulation in rat basophilic leukemic (RBL-2H3) cells, with inhibition of 98.7% and 87.5% at concentration of 100 microg/ml, respectively. These extracts were further separated by chromatographic techniques to give two chalcones and seven homoisoflavones. Among the compounds tested, sappanchalcone (2) possessed the most potent effect against allergic reaction in RBL-2H3 cells with an inhibitory concentration (IC50) value of 7.6 microM, followed by 3-deoxysappanchalcone (1, IC50 = 15.3 microM), whereas other compounds showed moderate and mild effects. The results suggested the following structural requirements of chalcones (1 and 2) and homoisoflavones (3-9) for anti-allergic activity: (i) chalcone exhibited higher activity than homoisoflavone (ii) vicinal hydroxylation at B-ring of chalcone conferred higher activity than one hydroxylation; and (iii) for homoisoflavone, the hydroxyl groups at C-3 and C-4 positions decreased the activity. This is the first report of C. sappan for anti-allergic activity.