Potential Anti-Inflammatory Constituents from Aesculus wilsonii Seeds.

A chemical study of Aesculus wilsonii Rehd. (also called Suo Luo Zi) and the in vitro anti-inflammatory effects of the obtained compounds was conducted. Retrieving results through SciFinder showed that there were four unreported compounds, aeswilosides I-IV (1-4), along with fourteen known isolates (5-18). Their structures were elucidated by extensive spectroscopic methods such as UV, IR, NMR, [α]D, and MS spectra, as well as acid hydrolysis. Among the known ones, compounds 5, 6, 8-10, and 12-16 were obtained from the Aesculus genus for the first time; compounds 7, 11, 17, and 18 were first identified from this plant. The NMR data of 5 and 18 were reported first. The effects of 1-18 on the release of nitric oxide (NO) from lipopolysaccharide (LPS)-induced RAW264.7 cells were determined. The results showed that at concentrations of 10, 25, and 50 µM, the novel compounds, aeswilosides I (1) and IV (4), along with the known ones, 1-(2-methylbutyryl)phloroglucinyl-glucopyranoside (10) and pisuminic acid (15), displayed significant inhibitory effects on NO production in a concentration-dependent manner. It is worth mentioning that compound 10 showed the best NO inhibitory effect with a relative NO production of 88.1%, which was close to that of the positive drug dexamethasone. The Elisa experiment suggested that compounds 1, 4, 10, and 15 suppressed the release of TNF-α and IL-1ß as well. In conclusion, this study enriches the spectra of compounds with potential anti-inflammatory effects in A. wilsonii and provides new references for the discovery of anti-inflammatory lead compounds, but further mechanistic research is still needed.

Antihyperglycemic effects of triterpenoid saponins from the seeds of Aesculus chinensis Bge.

Six undescribed triterpenoid saponins, namely aescuchinosides A-F, along with seven known triterpenoid saponins, were isolated from the seeds of Aesculus chinensis. Barrigenol-like triterpenoids (BATs) constitute these saponins. Protoaescigenin serves as their aglycone, with various oxygen-containing groups, including acetyl, isobutyryl, tigloyl, and angeloyl groups situated at C-21, C-22, and C-28. Various techniques, including 1D and 2D-NMR spectroscopy, high-resolution mass spectrometry, and acid hydrolysis, were employed to determine the structures of these compounds. The antihyperglycemic effects of the isolated compounds were examined in insulin -resistant HepG2 cells induced by palmitic acid treatment. At a concentration of 6 µM, aesculinoside F exhibited a significant increase in glucose consumption. In addition, aesculinoside F demonstrated the potential to improve insulin resistant by upregulating the PI3K/AKT pathway. These results indicate that the seeds of A.chinensis hold promising potential for preventing insulin resistant related disease.

Nitrogenous compounds from Aesculus wilsonii seeds.

Eight nitrogenous compounds including five undescribed ones, aeswilnitrousol A (1), aeswilnitrousosides BD (2-4), and 6-(2-hydroxy-3-methylbutylamino)-8-oxoadenine (5) were isolated from the seeds of Aesculus wilsonii. Their structures and absolute configurations were established based on spectroscopic determination, calculated electronic circular dichroism (ECD) analysis, as well as chemical reaction methods. Among the three known compounds, 7 and 8 were obtained from the Aesculus genus for the first time, and 6 was gained from this plant initially. The 13C NMR data of 7 and 8 were reported for the first time. Moreover, the inhibitory effect of all the isolates against LPS-induced nitric oxide production in RAW264.7 macrophages was evaluated. As a result, compounds 2 and 8 exhibited anti-inflammatory activity in a concentration-dependent manner at 10, 25, and 50 µM.

Horse Chestnut Saponins-Escins, Isoescins, Transescins, and Desacylescins.

Escins constitute an abundant family of saponins (saponosides) and are the most active components in Aesculum hippocastanum (horse chestnut-HC) seeds. They are of great pharmaceutical interest as a short-term treatment for venous insufficiency. Numerous escin congeners (slightly different compositions), as well as numerous regio-and stereo-isomers, are extractable from HC seeds, making quality control trials mandatory, especially since the structure-activity relationship (SAR) of the escin molecules remains poorly described. In the present study, mass spectrometry, microwave activation, and hemolytic activity assays were used to characterize escin extracts (including a complete quantitative description of the escin congeners and isomers), modify the natural saponins (hydrolysis and transesterification) and measure their cytotoxicity (natural vs. modified escins). The aglycone ester groups characterizing the escin isomers were targeted. A complete quantitative analysis, isomer per isomer, of the weight content in the saponin extracts as well as in the seed dry powder is reported for the first time. An impressive 13% in weight of escins in the dry seeds was measured, confirming that the HC escins must be absolutely considered for high-added value applications, provided that their SAR is established. One of the objectives of this study was to contribute to this development by demonstrating that the aglycone ester functions are mandatory for the toxicity of the escin derivative, and that the cytotoxicity also depends on the relative position of the ester functions on the aglycone.

New HPLC pattern-oriented approach for quality control of enteric coated tablets containing aescin from Aesculus hippocastanum.

From the seed of Aesculus hippocastanum L., a complex mixture of triterpene saponin glycosides known as aescin was isolated, purified and characterized to be an active pharmaceutical ingredient for preparing of drug products. A reversed phase high performance liquid chromatographic method with UV detection was developed for the determination of total triterpene glycosides in enteric coated tablets containing aescin in a pattern-oriented manner. The mobile phase consisted of a mixture of acetonitrile and 0.1 % phosphoric acid solution (40: 60). UV detection was performed at 220 nm. The chromatographic column was Gemini C18 column, 5 µm 250 mm × 4.6 mm, which was maintained at 25 ◦C, connected with a precolumn (C18, 4.0 × 3.0 mm, 5 µm). The linear range was from 53.4 to 160.1 µg·mL-1. The RSD of intra-and inter-day precision variations were less than 1 % and the mean recovery was (100.66 ± 0.49) % (RSD = 0.64 %). The method showed its suitability, simplicity, rapidity and precision. Accordingly, it was proven adequate for quality control of this herbal drug product either for registration with the regulartory authority or routine analysis.

Chestnut polysaccharides restore impaired spermatogenesis by adjusting gut microbiota and the intestinal structure.

Our previous study confirmed the beneficial effects of chestnut polysaccharides (CPs) on the spermatogenesis process, but the exact mechanism is not clear. Several studies have demonstrated the importance of balanced gut microbiota in maintaining normal reproductive function. In this study, we investigated the biological functions of CPs from the perspective of gut microbiota function, expecting to find out the specific mechanism of CPs in restoring impaired spermatogenesis. Compared with the control group, the mice treated with busulfan showed a reduced number of germ cells, structural changes in the small intestine and composition alteration in the gut microbiota at several levels, including the phylum and genus. In contrast, the number of germ cells in seminiferous tubules was significantly increased, and the structure of the small intestine and the composition of the gut microbiota were altered in the busulfan-treated mice after the CPs treatment. The 16s rRNA analysis results showed that the Firmicutes was the predominant phylum in all groups followed by Proteobacteria, Bacteroidetes, Actinobacteria, Tenericutes, Cyanobacteria and unidentified bacteria. Interestingly, the subsequent functional analysis implied that the steroid hormone biosynthesis process is the major metabolic pathway in the CPs-mediated restoration process and the experimental results confirmed this speculation. In conclusion, this study confirmed that CPs can restore the impaired spermatogenesis process by adjusting the gut microbiota and intestinal structure, which will also provide technical support and a theoretical basis for the subsequent treatment of male infertility.

Protective and proliferative effect of Aesculus indica extract on stressed human adipose stem cells via downregulation of NF-κB pathway.

Inflammatory microenvironment after transplantation affects the proliferation and causes senescence of adipose-derived mesenchymal stem cells (hADMSCs) thus compromising their clinical efficacy. Priming stem cells with herbal extracts is considered very promising to improve their viability in the inflammatory milieu. Aesculus indica (A. indica) is used to treat many inflammatory diseases in Asia for decades. Herein, we explored the protective role of A. indica extract on human adipose-derived Mesenchymal Stem Cells (hADMSCs) against Monosodium Iodoacetate (MIA) induced stress in vitro. A. indica ameliorated the injury as depicted by significantly enhanced proliferation, viability, improved cell migration and superoxide dismutase activity. Furthermore, reduced lactate dehydrogenase activity, reactive oxygen species release, senescent and apoptotic cells were detected in A. indica primed hADMSCs. Downregulation of NF-κB pathway and associated inflammatory genes, NF-κB p65/RelA and p50/NF-κB 1, Interleukin 6 (IL-6), Interleukin 1 (IL-1ß), Tumor necrosis factor alpha (TNF-α) and matrix metalloproteinase 13 (MMP-13) were observed in A. indica primed hADMSCs as compared to stressed hADMSCs. Complementary to gene expression, A. indica priming reduced the release of transcription factor p65, inhibitory-κB kinase (IKK) α and ß, IL-1ß and TNF-α proteins expression. Our data elucidates that A. indica extract preconditioning rescued hADMSCs against oxidative stress and improved their therapeutic potential by relieving inflammation through regulation of NF-κB pathway.

Whey Proteins as a Potential Co-Surfactant with Aesculus hippocastanum L. as a Stabilizer in Nanoemulsions Derived from Hempseed Oil.

The use of natural surfactants including plant extracts, plant hydrocolloids and proteins in nanoemulsion systems has received commercial interest due to demonstrated safety of use and potential health benefits of plant products. In this study, a whey protein isolate (WPI) from a byproduct of cheese production was used to stabilize a nanoemulsion formulation that contained hempseed oil and the Aesculus hippocastanum L. extract (AHE). A Box-Behnken experimental design was used to set the formulation criteria and the optimal nanoemulsion conditions, used subsequently in follow-up experiments that measured specifically emulsion droplet size distribution, stability tests and visual quality. Regression analysis showed that the concentration of HSO and the interaction between HSO and the WPI were the most significant factors affecting the emulsion polydispersity index and droplet size (nm) (p < 0.05). Rheological tests, Fourier transform infrared spectroscopy (FTIR) analysis and L*a*b* color parameters were also taken to characterize the physicochemical properties of the emulsions. Emulsion systems with a higher concentration of the AHE had a potential metabolic activity up to 84% in a microbiological assay. It can be concluded from our results that the nanoemulsion system described herein is a safe and stable formulation with potential biological activity and health benefits that complement its use in the food industry.

Effect of Coconut and Chestnut Flour Supplementations on Texture, Nutritional and Sensory Properties of Baked Wheat Based Bread.

Wheat bread, produced by the single-phase method, is a common food consumed all over the world. Due to changes in lifestyle and nutritional trends, alternative raw materials are sought to increase the nutritional value and improve the taste of daily consumed products. Additionally, customers seek a wide variety of foods, especially when it comes to basic foods. Nuts, such as coconuts or chestnuts, might provide an attractive flavour with benefits to the nutritional quality. In this study, the effect of substituting wheat flour with coconut or chestnut flour (flour contribution level: 5, 10, 15, 30, 50% w/w), was evaluated in terms of the breads specific volume, texture, colour, nutritional composition, and dietary fibre fraction contents. Moreover, a sensory evaluation was conducted to assess potential consumer acceptance. Based on the consumer's perception, the overall acceptance of bread with 15% w/w of coconut and chestnut flour was in privilege compared to the control sample. As a result, taking all of the tested parameters into account, the breads with 5, 10, and 15% supplementation of chestnut or coconut flour were still of good quality compared to the wheat bread and their fibre content was significantly higher.

Hypoglycemic and Anti-Inflammatory Effects of Triterpene Glycoside Fractions from Aeculus hippocastanum Seeds.

Horse chestnut (Aesculus hippocastanum L.)-derived drugs have shown their potential in biomedical applications. The seed of A. hippocastanum contains various kinds of chemical compounds including phenolics, flavonoids, coumarins, and triterpene saponins. Here, we investigated the chemical components in A. hippocastanum L. grown in Uzbekistan, which has not yet been studied in detail. We identified 30 kinds of triterpene saponins in an extract of A. hippocastanum L. Classifying extracted saponins into eight fractions, we next studied the hypoglycemic and the anti-inflammatory activities of escin and its derivatives through in vivo experiments. We came by data indicating the highest (SF-1 and SF-2) and the lowest (SF-5 and SF-8) antidiabetic and anti-inflammatory effects of those eight fractions. These results imply the prospective use of A. hippocastanum L. grown in Uzbekistan in the production of pharmaceutical drugs to treat diabetes and inflammation.

Polyphenol Profiling of Chestnut Pericarp, Integument and Curing Water Extracts to Qualify These Food By-Products as a Source of Antioxidants.

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6-7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut's appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

Effect of Hydrolysable Tannins and Anthocyanins on Recurrent Urinary Tract Infections in Nephropathic Patients: Preliminary Data.

Urinary tract infections (UTIs) are caused by uropathogenic microorganism colonization. UTIs often require an antibiotic therapy that can cause the selection of antibiotic-resistant bacterial strains. A natural bioactive compound may represent a valid therapeutic adjuvant approach, in combination with drug therapy. In this paper, we present a pilot study, based on the administration of an oral food supplement (OFS), containing chestnut tannins and anthocyanins, to nephropathic patients suffering from recurrent UTIs (16 treated patients with 1 cp/day and 10 untreated patients). We performed laboratory tests and quality of life and body composition assessments, at T0 (baseline) and T1 (after 6 weeks OFS assumption). The analysis of OFS was performed by HPLC-DAD-MS for its content in polyphenols and by in vitro tests for its antioxidative and anti-free radical activities. In each capsule, polyphenol content was 6.21 mg (4.57 mg hydrolysable tannins, 0.94 mg anthocyanosides, 0.51 mg proanthocyanidins, 0.18 mg quercetin derivatives). A significant reduction of erythrocyte sedimentation rate was observed only in male patients. Urinalysis showed a significant reduction of leukocytes in both genders, whereas urinary bacterial flora at T1 significantly decreased only in male subjects. Tannins seem to exert an antimicrobial action according to gender, useful to counteract the recurrence of UTIs.

Influence of the Storage in Bottle on the Antioxidant Activities and Related Chemical Characteristics of Wine Spirits Aged with Chestnut Staves and Micro-Oxygenation.

Different ageing technology of wine spirits (WSs) has been investigated, but little has been published on the chemical evolution of aged WS during storage in bottle. The purpose of this study was to examine how 12 months of storage in bottle affected the evolution of antioxidant activity (DPPH, FRAP and ABTS assays), total phenolic index (TPI) and low molecular weight (LMW) compounds content of the WSs aged through alternative technology using three micro-oxygenation levels (MOX) and nitrogen control (N). Results revealed the ability of phenolic compounds from aged WSs to scavenge free radicals during storage in bottle. Among the in vitro antioxidant-activity methods, FRAP assay was the more effective to differentiate WSs according to the ageing technology. Concerning the overall influence of storage in bottle on antioxidant activity, and TPI and LMW compounds content, the higher results were obtained for the MOX modalities (O15, O30 and O60), which showed a similar evolution. In summary, this study provides innovative information, demonstrating that the differences between the aged WSs imparted throughout the ageing process (resulting from different MOX levels) were mostly retained, and only slight modifications during storage in bottle were found.

Optimizing the extraction of phenolic antioxidants from chestnut shells by subcritical water extraction using response surface methodology.

The objective of this study was to evaluate the optimal Subcritical Water Extraction (SWE) conditions of antioxidants and polyphenols from chestnut shells using Response Surface Methodology (RSM). A central composite design (CCD) was conducted to analyse the time (6-30 min) and temperature (51-249 °C) effects in antioxidant activity (ABTS, DPPH and FRAP) and Total Phenolic Compounds (TPC). TPC ranged from 315.21 to 496.80 mg gallic acid equivalents (GAE)/g DW; the DPPH from 549.23 to 1125.68 mg Trolox equivalents (TE)/g DW; ABTS varied between 631.16 and 965.45 mg ascorbic acid equivalents (AAE)/g DW and FRAP from 2793.95 to 11393.97 mg ferrous sulphate equivalents (FSE)/g DW. The optimal extraction conditions were 30 min/220 °C, revealing excelling scavenging efficiencies against HOCl (IC50 = 0.79 µg/mL) and O2- (IC50 = 12.92 µg/mL) without toxicity on intestinal cells (0.1 µg/mL). The phenolic composition revealed high amounts of pyrogallol and protocatechuic acid. SWE can be a useful extraction technique for the recovery of polyphenolics from chestnut shells.

Usability of soapwort and horse chestnut saponin extracts as foaming agents in foam mat drying of pomegranate juice.

BACKGROUND: This study evaluated the usability of saponin-rich extracts (soapwort and horse chestnut) as a foaming agent for foam mat drying of pomegranate juice. RESULTS: According to the foaming and stabilization studies, the optimum conditions were determined as 0.4% of soapwort extract, 0.03% of carboxymethyl cellulose as a stabilizer, and 3 min of whipping time. The foams produced using these conditions were dried at different spreading thicknesses and drying temperatures. The results showed that the thicker spreading thicknesses provided a higher antioxidant activity. On the other hand, drying temperature had a significant effect on all measured parameters except moisture content and water activity. The higher drying temperature caused a greater colour change and a lower content of total phenolics, total monomeric anthocyanins, cyanidin-3-glucoside, and delphinidin-3-glucoside. On the other hand, a higher content of ascorbic acid and better antioxidant activity was determined in the samples dried at 70 °C. CONCLUSION: According to the results obtained, spreading thickness of 2 mm and drying temperature of 70 °C were suggested for pomegranate juice powder production by foam mat drying. Overall, it was demonstrated that saponin-rich extracts are a good foaming agent alternative that provides foaming at very low concentrations and a product with high quality. © 2020 Society of Chemical Industry.

Effect of chestnut wood extract on performance, meat quality, antioxidant status, immune function, and cholesterol metabolism in broilers.

Plant extracts have been proved as natural antioxidants resources as well as alternative feed additives in livestock and poultry species. Chestnut wood extract (CWE) as a source of hydrolysable tannic acid was used to evaluate the growth performance, nutrient retention, meat quality, antioxidant status, and immune function of broilers. A total of 168, day-old Arbor Acre male broilers (weight 46.59 ± 0.44 g) were randomly divided to 3 treatments, 7 replicate pens per treatment, 8 broilers per pen. The treatments contain a control diet, CON (corn-soybean meal basal diet); an antibiotic diet, CTC (basal diet + 75 mg/kg chlortetracycline); and chestnut wood extract diet, CWE (basal diet + 1,000 mg/kg chestnut tannins). At the finisher phase, final body weight was higher (P < 0.05) in CWE supplemented diet than in CON. Average daily body weight gain was higher (P < 0.05) and feed gain ratio was lower (P < 0.05) in broilers fed CWE than in those fed CON at the finisher phase. Crude protein digestibility was higher (P < 0.05) in broilers offered CWE than that in broilers fed CON and CTC diets. Breast muscle pH value at 24 h (pH24 h) was higher (P < 0.05) in broilers fed CWE than that in those fed CON and CTC diets. The bursa weight was higher (P < 0.05) in broilers offered CWE than that in those fed CON and CTC. Total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) values were higher (P < 0.05) in both breast muscle and thigh muscle of broilers offered CWE supplemented diet than those in broilers fed CON and CTC diets. Similarly, broilers offered with CWE diets showed higher (P < 0.05) T-AOC, GSH-PX, and SOD value in serum than those fed CON and CTC diets. Serum concentration of IgG was higher (P < 0.05) in broilers offered with CWE diets than that in those fed CON and CTC diets. Total cholesterol, low-density lipoprotein cholesterol, and urea-N concentration were lower (P < 0.05) in broilers offered CWE diet than those in broilers fed CON and CTC diets. It was recommended to supply CWE at the 1,000 mg/kg level for improving antioxidant status, cholesterol metabolism, and growth performance without affecting normal meat quality in broilers.

Phytochemical, ethanomedicinal and pharmacological applications of escin from Aesculus hippocastanum L. towards future medicine.

Medicinal plants are used from ancient times for treatment of various ailments. Aesculus hippocastanum (Horse chestnut), is the popular and most valuable tree native to the South East Europe. It's seed extracts and their concentrates contain phytocompounds like flavonoids, polyphenols, triterpenoid saponin glycosides (escin), epicatechin, tannins, kaempferol, esculin, fraxin, carbohydrate, essential fatty acids (linoleic acid), oleic acid and purine bases (adenine and guanine). Due to these vital phyto-constituents, horse chestnut is used in phytomedicine for the prevention and treatment of diverse disorders as in venous congestion in leg ulcers, bruises, arthritis, rheumatism, diarrhoea, phlebitis etc. We collected the pharmacological applications of Aesculus hippocastanum L. extracts and escin as the cheif bioactive compound and their uses in traditionally and clinically for the management of various disorders. This review describes the efficacy of A. hippocastanum L. extracts and their bioactive compounds. So in the furtue this plant may be useful for the alternative treatment measure for various ailments via incorporating either extract or escin into novel delivery systems for improving the social health in future and would provide improved quality of life.

Subcritical Water Extraction of Chestnut Bark and Optimization of Process Parameters.

The aim of the work was the optimization of the subcritical water extraction process of chestnut bark using Box-Behnken response surface methodology. The influence of process parameters, such as temperature, extraction time and solvent-solid ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity has been investigated. The identified compounds were ellagic and gallic acids, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin, vescalin and castalin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). Finally, the optimal process conditions for obtaining the bark extract highly rich in ellagic acid and with satisfactory levels of total phenols and total tannins have been determined.

Aesculus hippocastanum L. Extract Does Not Induce Fibroblast to Myofibroblast Conversion but Increases Extracellular Matrix Production In Vitro Leading to Increased Wound Tensile Strength in Rats.

The ability of horse chestnut extract (HCE) to induce contraction force in fibroblasts, a process with remarkable significance in skin repair, motivated us to evaluate its wound healing potential in a series of experiments. In the in vitro study of the ability of human dermal fibroblasts to form myofibroblast-like cells was evaluated at the protein level (Western blot and immunofluorescence). The in vivo study was conducted on male Sprague-Dawley rats with inflicted wounds (one open circular and one sutured incision) on their backs. Rats were topically treated with two tested HCE concentrations (0.1% and 1%) or sterile water. The control group remained untreated. The incisions were processed for wound tensile strength (TS) measurement whereas the open wounds were subjected to histological examination. On the in vitro level the HCE extract induced fibronectin-rich extracellular matrix formation, but did not induced α-smooth muscle actin (SMA) expression in dermal fibroblasts. The animal study revealed that HCE increased wound TS and improved collagen organization. In conclusion, the direct comparison of both basic wound models demonstrated that the healing was significantly increased following HCE, thus this extract may be found useful to improve healing of acute wounds. Nevertheless, the use of an experimental rat model warrants a direct extrapolation to the human clinical situation.

Resistant starch from five Himalayan rice cultivars and Horse chestnut: Extraction method optimization and characterization.

In this study resistant starch (RS) was extracted from five Himalayan rice cultivars and Indian Horse chestnut (HCN) using porcine pancreatin enzyme following which it was subsequently characterized for its physicochemical, structural and functional properties. In vitro digestibility test showed that RS content of the rice cultivars and HCN was in the range of 85.5 to 99.5%. The RS extracted from the rice cultivars and HCN showed significant difference in the apparent amylose content (AAC), ranging between 31.83 to 40.68% for rice and 45.79% for HCN. Water absorption capacity (WAC), swelling and solubility index of RS ranged from 112-133.9%, 5.28-7.25 g/g and 0.033-0.044 g/g, respectively. The rice RS granules were polyhedral and irregular shaped with granular length in the range of 4.8-5.9 µm. The HCN RS granule morphology showed smooth surfaced, round, elliptical, irregular and oval shapes with average granular length of 21 µm. Pasting behavior also varied significantly between rice RS and HCN RS with later showing the lower values of pasting properties. Thermal properties (T0, Tp, Tc) and ΔH gel also varied considerably between the rice RS and HCN RS, wherein the highest values for peak gelatinization temperature and gelatinization enthalpy were seen for CH-1039. X-ray diffraction pattern of rice RS and HCN RS showed the characteristic A type of pattern in consonance with cereal starches.