Determination of steroidal saponins in different organs of yam (Dioscorea pseudojaponica Yamamoto)

Yams (Dioscorea spp.) are perennial trailing rhizome plants. Steroidal saponins, furostanol and spirostanol glycosides are the marked functional compounds in yams. In this investigation, a C18 solid phase extraction method was developed for yam saponins purification. The contents of saponins in various organs of yam (Dioscorea pseudojaponica Yamamoto) were also determined. Results showed that the recoveries of yam saponins extracted by the developed method were about 99.48–100.08% when the saponins (each saponin weighed 0.20, 0.50 and 1.00 mg) passing through the C18 cartridge. The extractive method could efficiently reduce the interferences from impurities in yam saponin extracts prior to HPLC analysis. The recoveries of added saponins in different yam organs were 98.34–99.92% for tuber flesh, 95.98–98.89% for tuber cortex, 97.89–99.44% for rhizophor, 93.82–98.01% for leaf and 93.87–97.65% for vine, respectively. The yam tuber cortex had the highest amount of saponins (582.53 μg/g dw), which was higher than that existed in the tuber flesh (227.86 μg/g dw) about 2.55 times. The contents of saponins in the rhizophor, leaf and vine of yam were 29.39, 24.41 and 23.96 μg/g dw, respectively.     

Centrifugation and Foam Fractionation Effect on Mucilage Recovery from Dioscorea (Yam) Tuber

ABSTRACT: The yam ( Dioscorea spp., Dioscoreaceae ) is an important pharmaceutical plant that can be widely applied in the drug industry. The yam tuber is rich in starch and mucilage however, it is difficult to separate the starch from the tuber because of the viscous soluble carbohydrates-protein (glycoprotein) present in the yam. These surface-active complexes produce an extensive amount of foam. Foam fractionation is recognized as a suitable technique for recovering soluble, surface-active substances from a solution using preferential adsorption at the gas-liquid interface. The objective of this research is to compare foam fractionation and centrifugation for recovering the mucilage from yam tuber. The soluble carbohydrates and protein present in the mucilage are analyzed. The results showed that centrifugation may break down the soluble carbohydrates and protein complex, resulting in further soluble carbohydrates and protein separation in different parts of the starch paste and mucilage. With 2 consecutive centrifugations (7300 × g ), the total amounts of soluble carbohydrates and protein recovered from the Keelung yam ( D. pseudojaponica Y.) tuber were 4.8% and 33.8%, respectively. It was found that excellent soluble carbohydrates (98.8%) and protein (74.1%) yield can be recovered in the Keelung yam using foam fractionation. Foam fractionation provides an alternative method for recovering viscous mucilage from yam. This is especially suitable for starch-rich samples from the tuber.     

Effects of mucilage on the thermal and pasting properties of yam, taro, and sweet potato starches

This study investigates the effects of water-soluble mucilages (0, 2.5, and 5 g/100 g; w/w, dry basis) on the thermal and pasting properties of isolated starches from three root and tuber crops. The results show that yam tuber presents the greatest level of mucilage and also possess the largest amylose content of the three isolated starches. The addition of mucilage caused a remarkable increase in the temperature of gelatinization for the three tested starches due to the competition for water during starch gelatinization. Furthermore, adding mucilage increased the phase transition temperature range (Tc-To) of starches but decreased enthalpy (ΔH). However, although the pasting temperature increased with the addition of mucilage into tuber starches, it did not change that of taro starch. The peak viscosity of taro and sweet potato starches decreased significantly as their mucilages were added into each starch suspension system (p < 0.05). However, the addition of mucilage slightly increased the viscosity of yam starch. Furthermore, the addition of mucilage slightly increased the swelling power of yam and taro starches, but did not change that of sweet potato starch.     

Use of continuous bubble separation process for separating and recovering starch and mucilage from yam (Dioscorea pseudojaponica yamamoto)

The yam (Dioscorea pseudojaponica Yamamoto) tuber is abundant in both starch and mucilage. It is difficult to separate yam starch from its tuber because of the presence of viscous polysaccharide polymers (glycoprotein). The surface-active polysaccharide-containing complexes are capable of forming foams. The goal of this study was to develop a continuous bubble separation process for separating and recovering starch and mucilage from yam tubers in the absence of undesirable chemical additives or treatments. The results showed that the highest concentration (13.2 g/100 g) of yam slurry mucilage was obtained with a reasonably high yield of recovered starch (91.2 g/100 g) by treating the starch paste with 1 g/100 g Viscozyme^® L and Pectinex^® Ultra SP-L. In comparison with the total amount of yam fed into the system, the yield of soluble carbohydrates and protein in separated mucilage were 98.8 g/100 g and 74.1 g/100 g, respectively. The chemical composition of the separated freeze-dried mucilage was shown to be high in soluble carbohydrates (52.5 g/100 g, dry basis) and protein (40.3 g/100 g, dry basis). A very low amount of starch (0.8 g/100 g) remained in the mucilage. This method is simple, low in operational and capital costs, and especially suitable for polysaccharide–protein-containing complexes recovering from a starch-containing system.     

Antioxidant and trypsin inhibition activity of dioscorin influenced by yam cultivars and eluent pH

The total antioxidant activity (TAA) and trypsin inhibition activity (TIA) of storage protein dioscorin from six yam cultivars (Dashan, Hualien No. 3, Keelung, Mingchien, Tainong No. 2, and Japanese yam) were demonstrated. Japanese yam had the highest TAA and the lowest calculated EC₅₀ at any purification stage. Following gel permeation, dioscorins purified from Hualien No. 3 and Japanese yam showed the highest TIA and lowest calculated IC₅₀. Dioscorin with higher TIA apparently possesses better TAA. The pIs of dioscorin from all yam species were in the range of 5.94–4.33 indicating acidic protein in nature. Results from isoelectric focusing chromatography showed regardless of species higher TIA for dioscorin eluted at lower pH.     

Phenolic content and antioxidant capacity of Philippine sweet potato (Ipomoea batatas) varieties

The study established baseline data on the total phenolic content and antioxidant activities of five sweet potato (Ipomoea batatas) varieties grown in the Philippines including Dakol, Emelda, Haponita, PSBSP and Violet. Phenolic content ranged from 192.7 to 1159.0 mg gallic acid equivalent (GAE) /100 g dry sample. Antioxidant activities were highest for Dakol, with an EC₅₀ value of 0.7 ± 0.2 mg/mL for DPPH radical scavenging activity, 2.5 ± 0.5 mg/mL for reducing power, and 2.4 ± 0.3 mg/mL for iron-chelating ability, on a dry basis. However, Haponita had the best inhibitory action on linoleic acid oxidation at 99.4 ± 0.9%. Methanolic sweet potato extracts had higher radical scavenging activity, reducing power and oxidation inhibition than α-tocopherol and higher iron-chelating capacity than ethylenediamine tetraacetic acid (EDTA). Significant (∗P < 0.05) negative correlation was observed between total phenolic content and the EC₅₀ for DPPH radical scavenging activity (R = −0.826), reducing power (R = −0.876) and iron-chelating capacity (R = -0.800).     

Dietary fiber,amino acid,fatty acid and tocopherol contents of the edible seaweeds Ulva lactuca and Durvillaea antarctica

The nutritional composition of the edible seaweeds Durvillaea antarctica (frond and stem) and dried Ulva lactuca was determined, including the soluble (SDF), insoluble (IDF) and total (TDF) dietary fiber content, amino acid and fatty acid profiles along with tocopherols and tocotrienols (pro-vitamin E). Results show that U. lactuca contained 60.5 ± 1.5%, and D. antarctica frond and stem 71.4 ± 1.5% and 56.4 ± 0.4% of TDF, respectively. Levels for the different amino acids ranged from 0.7 ± 0.1 to 1508.4 ± 9.5 (mg/100 g protein) in U. lactuca, from 0.2 ± 0.0 to 2019.9 ± 5.2 (mg/100 g protein) in D. antarctica (stem), and from 0.3 ± 0.0 to 1052.6 ± 2.9 (mg/100 g protein) in D. antarctica (leaves). In the three seaweeds, the most abundant fatty acid was C18:1ω9cis which in U. lactuca accounted for 27.42 ± 2.60%; in D. antarctica it was 25.36 ± 3.10% and 25.83 ± 2.52% in leaves and stem, respectively. In D. antarctica, γ-tocotrienol (651.7 ± 5.1 mg/kg), δ-tocopherol (245.9 ± 3.7 mg/kg) and α-tocopherol (179.4 ± 12.1 mg/kg) were determined in fronds, α-tocopherol (258.0 ± 7.2 mg/kg) was determined in stem. U. lactuca, showed a high γ-tocopherol level (963.5 ± 3.8 mg/kg).     

Saponins in Ipomoeabatatas tubers: Isolation,characterization, quantification and antioxidant properties

Triterpene saponins are a class of plant natural products with a wide range of bioactivities, which makes them an interesting research subject. This work reports, for the first time, the isolation and characterization of saponins in Ipomoeabatatas tuber flour, their quantification and antioxidant properties. Their structures were characterized on the basis of UV, FAB–MS, ESI–MS, GC–MS, polarimetry and NMR data, as: oleanolic acid-3-O-[β-d-glucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→2)-β-d-glucuronopyranosyl]-28-O-β-d-glucopyranoside (sandrosaponin IX) (1) and oleanolic acid-3-O-[β-d-galactopyranosyl-(1→3)-β-d-glucuronopyranosyl]-28-O-β-d-glucopyranoside (2). A new quantitative HPLC–DAD method for saponin content determination in this tuber was developed and validated. Their total content was 200.01 mg/100 g dry weight (RSD = 7.2%; p < 0.001). The single saponin contents were: 161.20 mg/100 g dry weight (RSD = 0.58%; p < 0.001) for saponin 1 and 14.67 mg/100 g dry weight (RSD = 0.41%; p < 0.001) for saponin 2. The antioxidant activities, tested by DPPH and FRAP assay, of total phytochemical fraction and of single saponins were moderate in relation to commercial standards.     

Chemical compositions and some physical properties of the water and alkali-extracted mucilage from the young fronds of Asplenium australasicum (J. Sm.) Hook

Effect of extraction conditions, including solvent types (water and sodium bicarbonate) and extraction temperatures (25, 50, 70 and 90 °C), on the physicochemical properties of the water and alkali-extracted mucilage from the young fronds of Asplenium australasicum (J. Sm.) Hook was evaluated. It was found that sodium bicarbonate extract generally showed higher yield than water extract, and its yield increased with increasing extraction temperature. Composition analysis revealed that A. australasicum mucilage was composed of mainly carbohydrates in conjunction with some glycoproteins. The weight average molecular size of the carbohydrate fraction of crude mucilage obtained from alkali and water extractions were about 6.30 × 10⁷ and 2.63 × 10⁷, respectively. Sugar composition analysis revealed that A. australasicum young fronds mucilage contained significant amount of uronic acid (14.3-56.6% based on total sugars). For the water extracted mucilage, GlcA is predominant. However, for the sodium bicarbonate extracted mucilage, GalA is predominant. Furthermore, Rha can only be detected in sodium bicarbonate extract. Other major neutral sugars include Gal, Man, Xyl and Fuc. The intrinsic viscosity of the water and alkali-extracted mucilage in deionized water were around 21.12 and 5.92 dL/g, respectively. This information would be useful when considering A. australasicum young fronds mucilage as a new Agro-ingredient.     

Chemical compositions and enzyme activity changes occurring in yam (Dioscorea alata L.) tubers during growth

The purpose of this study was to establish the chemical compositions, enzyme activity and nutritional values of four cultivars of yam tubers at different stages of their maturation, and compare such levels during yam growth. The results have indicated that yam tubers featured a reasonably substantial content of protein when compared with other root and tuber crops, the protein content being of the order of 10.4-13.0 g/100 g (dry basis (db)) at time of harvest (day 260 post-emergence). Starch content of the four yam tubers increased as growth progressed and remained in the range of 70.5-85.3 g/100 g (db) during their growth period. The activity of yam-contained polyphenol oxidase (PPO) decreased remarkably over the early period of harvest (day 155-225 post-emergence), and subsequently decreased only slightly as growth progressed to harvest for all tested species of yam with the exception of CH yam tubers. Contrasting this, however, the activity of α-amylase increased significantly over the growth period for all cultivars, and dioscorin content of yam tuber also increased as growth progressed for all cultivars. All yam cultivars contained remarkably substantial amounts of essential amino acids, all of which were superior to the FAO reference pattern for such amino acids except for sulfur-containing amino acids and lysine contents.     

The flavonoid,carotenoid and pectin content in peels of citrus cultivated in Taiwan

The flavonoid, carotenoid and pectin composition in peels of eight varieties of citrus {Ponkan (Citrus reticulata Blanco), Tonkan (C. tankan Hayata), Murcott (C. reticulate × C. sinensis), Wendun (C. grandis Osbeck), Peiyou (C. grandis Osbeck CV), Kumquat (C. microcarpa), Liucheng [C. sinensis (L.) Osbeck], and Lemon [C. limon (L.) Bur]} cultivated in Taiwan was determined. The total flavonoid content exceeded the total carotenoid content. Ponkan (C. reticulata Blanco) peel had the highest total carotenoid content (2.04 ± 0.036 mg/g db) and Wendun (C. grandis Osbeck) and Peiyou (C. grandis Osbeck CV) peels, the lowest (0.036 ± 0.0006 and 0.021 ± 0.0004 mg/g db, respectively). Naringin was abundant in Peiyou (C. grandis Osbeck CV) and Wendun (C. grandis Osbeck) peels (29.8 ± 0.20 and 23.9 ± 0.32 mg/g db, respectively) and hesperidin was aboundant in Ponkan (C. reticulata Blanco), Tonkan (C. tankan Hayata), and Liucheng [C. sinensis (L.) Osbeck] peels (29.5 ± 0.32, 23.4 ± 0.25, 20.7 ± 0.38 mg/g db, respectively). Kumquat (C. microcarpa) peel contained the most diosmin (1.12 ± 0.03 mg/g db) and quercetin (0.78 ± 0.003 mg/g db). Levels of caffeic acid (3.06 ± 0.03–80.8 ± 3.72 μg/g db) were much lower than that of chlorgenic acid, ferulic acid, sinapic acid and ρ-coumaric acid. Ponkan (C. reticulata Blanco), Kumquat (C. microcarpa) and Liucheng [C. sinensis (L.) Osbeck] peels contained the most total amounts of lutein, zeaxanthin, β-cryptoxanthin, and β-carotene (114, 113, and 108 mg/g db, respectively). The total pectin content ranged from 36.0 ± 1.46 to 86.4 ± 3.36 mg/g db.     

Enzymatic hydrolysis of potato starches containing different amounts of phosphorus

The rapid hydrolysis of potato starches differing in phosphorus content, as well as sweet potato, cassava and yam starches, was accomplished by treatment of gelatinised starches with bacterial liquefying α-amylase at 50 °C for 1 h, followed by Bacillus licheniformis α-amylase at 55 °C up to 24 h, and then by glucoamylase at 40 °C for a further 24 h. Among the potato starches, the high-phosphorus starches showed higher starch resistant capacity than the medium-phosphorus starches, as well as other tuber and root starches. The hydrolysis rate of tuber and root starches was not greatly influenced by their amylose content and median granule size. Only glucose was detected in the almost completely hydrolysed tuber and root starch samples, indicating that the concomitant enzymes treatment could hydrolyse both the α-1,4 and α-1,6 linkages of the starches examined.     

Antioxidant and radical scavenging activities of the pyroligneous acid from a mangrove plant, Rhizophora apiculata

Total phenolics content, free radical scavenging activity, reducing power, and antioxidant activity of the pyroligenous acid from a mangrove plant, Rhizophora apiculata were evaluated. Dichloromethane extraction of the raw pyroligneous acid successfully yield 2 extracts, i.e. concentrated pyroligneous acid (CPA) and concentrated pyroligneous acid extract (CPAE). Phenolic contents in CPAE and CPA, expressed as (±)-catechin equivalents/g of the sample were 5465 ± 367 mg and 2502 ± 152 mg, and expressed as gallic acid equivalents/g of the sample were 2919 ± 209 mg and 1348 ± 90 mg, respectively. CPAE exhibited superior free radical scavenging activity with EC₅₀ value = 0.1235 mg/ml, or 80.96% of free radical scavenging capability. The ferric reducing power of CPAE was approximately 3.7, 5.1, 6.1, and 21.3 times higher than that of ascorbic acid, BHA, BHT and alpha-tocopherol. In phosphomolybdenum assay, CPAE showed the greatest antioxidant efficacy (A₆₉₅ = 1.278) compared to those of CPA and different standards. In addition, the free radical scavenging activity, ferric reducing power and total antioxidative activity of CPAE and CPA showed positive correlation with their total phenolic content with R² values ranging from 0.9624 to 0.9979.     

Uptake and utilization of trans octadecenoic acids in lactating dairy cows

Trans fatty acids (FA) arise in ruminant-derived foods as a consequence of rumen biohydrogenation and are of interest because of their biological effects and potential role in chronic human diseases. Our objective was to compare 2 trans FA, elaidic acid (EA; trans-9 18:1) and vaccenic acid (VA; trans-11 18:1), with oleic acid (OA; cis-9 18:1) relative to plasma lipid transport and mammary utilization for milk fat synthesis. Three ruminally cannulated, Holstein dairy cows, 259 ± 6 DIM (mean ± SEM), were randomly assigned in a 3 × 3 Latin square design. Treatments were a 4-d abomasal infusion of 1) OA (45.5 g/d), 2) EA (41.7 g/d), and 3) VA (41.4 g/d). Milk samples were collected at each milking and blood samples were collected at the start and end of each treatment period. The proportions of total plasma FA associated with each plasma lipid fraction at baseline (pretreatment) were 62.6 ± 0.6% phospholipids, 26.1 ± 0.6% cholesterol esters, 9.8 ± 0.4% triglycerides, and 1.5 ± 0.1% nonesterified fatty acids; these values were unaffected by treatment. There were striking differences in the FA composition of the individual plasma lipid fractions and in the distribution of specific 18-carbon FA among the lipid fractions. Infusion of treatment isomers caused their specific increase in the various plasma lipid fractions but had no effect on milk production variables, including milk fat yield and content. Transfer efficiency of infused OA, EA, and VA to milk fat averaged 65.5 ± 3.0%, 59.7 ± 1.5%, and 54.3 ± 0.6%, respectively. For the VA infusion, 24.6 ± 1.1% of the transfer was accounted for by the increased yield of cis-9, trans-11 conjugated linoleic acid in milk fat, consistent with its endogenous synthesis from VA via the mammary enzyme Δ⁹-desaturase. Notably, linoleic acid (18:2n-6) and linolenic acid (18:3n-3) accounted for 47.7% of total plasma FA, but only 2.6% of FA in milk. Overall, results demonstrate clear differences in plasma transport and mammary uptake and utilization of 18-carbon FA, and these relate to the location, orientation, and number of double bonds.     

Chemiluminescent screening of quenching effects of natural colorants against reactive oxygen species: Evaluation of grape seed,monascus, gardenia and red radish extracts as multi-functional food additives

The quenching effects of commercial available natural colorants against reactive oxygen species (ROS) were investigated. The effectiveness was evaluated by measuring the quenching ratio of chemiluminescence (CL) intensity with each colorant on luminol or methyl-6-(p-methoxyphenyl)-3,7-dihydroimidaz[1,2-a]pyrazin-3-one CL induced by ROS. As a result, the grape seed extracts and polyphenolics dose-dependently quenched CL. The quenching effects of grape seed extract A at 1 mg/ml for superoxide, singlet oxygen, hydroxyl radical, hypochlorite ion and linolenic acid peroxide were 81.1 ± 0.5%, 95.7 ± 0.4%, 99.3 ± 0.3%, 27.7 ± 4.2% and 88.3 ± 1.0%, respectively (n = 3). Except for chalcone, the polyphenolics, such as pelargonidin, cyanidin, delphinidin and trans-resveratrol, also showed the high quenching effects against ROS. These results suggested that the grape seed extract might be useful as a multi-functional food additive.     

Chemical composition and antioxidant activity of the essential oil of Clinopodium vulgare L.

This study was designed to examine the chemical composition and in vitro antioxidant activity of the essential oil of Clinopodium vulgare. GC–MS analysis of the oil resulted in the identification of 40 compounds, representing 99.4% of the oil; thymol (38.9%), γ-terpinene (29.6%) and p-cymene (9.1%) were the main components. The samples were subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, IC₅₀ value of the C. vulgare essential oil was determined as 63.0 ± 2.71 μg/ml. IC₅₀ value of thymol and γ-terpinene, the major compounds of the oil, was determined as 161 ± 1.3 μg/ml and 122 ± 2.5 μg/ml, respectively, whereas p-cymene did not show antioxidant activity. In β-carotene-linoleic acid system, C. vulgare essential oil exhibited 52.3 ± 1.19% inhibition against linoleic acid oxidation. In both systems, antioxidant capacities of BHT, curcumine and ascorbic acid were also determined in parallel experiments.     

Antioxidant,anticholinesterase and antimicrobial constituents from the essential oil and ethanol extract of Salvia potentillifolia

The essential oil of Salvia potentillifolia was analysed by GC and GC–MS. Totally, 123 components were detected in both hydrodistilled and steam-distilled oils, α- and β-pinenes being major compounds. The antioxidant activities were determined by using complementary tests, namely, DPPH radical-scavenging, β-carotene-linoleic acid and reducing power assays. The ethanol extract also showed better activity (IC₅₀ = 69.4 ± 0.99 μg/ml) than that of BHT in the DPPH system, and showed great lipid peroxidation inhibition in the β-carotene-linoleic acid system (IC₅₀ = 30.4 ± 0.50 μg/ml). The essential oil showed meaningful butyrylcholinesterase activity (65.7 ± 0.21%), and α-pinene showed high acetylcholinesterase inhibitory activity (IC₅₀ = 86.2 ± 0.96 μM) while β-pinene was inactive. Antimicrobial activity was also investigated on several microorganisms, and the essential oil showed high activity against Bacillus subtilis and B. cereus. It also exhibited remarkable anticandidal activity against Candida albicans and C. tropicalis with MIC values of 18.5 and 15.5 μg/ml, respectively, while α- and β-pinenes showed moderate activity.     

Changes of phenolic acids and antioxidant activities during potherb mustard (Brassica juncea, Coss.) pickling

Phenolic acids in potherb mustard (Brassica juncea, Coss.) were determined and the effects of pickling methods on the contents of total free phenolic acids, total phenolic acids, total phenolics, and antioxidant activities were investigated. Gallic acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid were identified in the present study. The contents of total free phenolic acids, total phenolic acids and total phenolics in fresh potherb mustard were 84.8 ± 0.58 μg/g dry weight (DW), 539 ± 1.36 μg/g DW, and 7.95 ± 0.28 mg/g DW, respectively. The total free phenolic acids increased during the pickling processes, but the total phenolic acids, total phenolics, and antioxidant activities decreased. However, after 5 weeks of fermentation, all the pickling methods retained over 70% of total phenolic contents and above 65% of antioxidant capacities. The results indicated that pickling processes were relatively good methods for the preservation of phenolic acids and antioxidants for potherb mustard.     

Technical note: Vaginal absorption of 1,25(OH)2D3 in cattle

Although exogenous 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] administered via intravenous, intramuscular, and oral routes has been tested for efficacy in preventing parturient hypocalcemia in dairy cows, there are few reports concerning intravaginal administration. For this study, 1,25(OH)₂D₃ was administered via the bovine vaginal lumen, and subsequent changes in blood chemistry, including levels of 1,25(OH)₂D₃ and several minerals, were measured to confirm vaginal absorption. Each of 5 heifers received a single intravaginal dose of 1 μg of 1,25(OH)₂D₃/kg body weight; a single control heifer received the ethanol carrier alone. In heifers receiving 1,25(OH)₂D₃, the plasma 1,25(OH)₂D₃ levels increased markedly from baseline (88.3 ± 20.3 pg/mL) within 2 h and reached a peak at 6 h after treatment (1967.4 ± 1139.6 pg/mL). Plasma Ca levels increased from baseline (10.4 ± 0.4 mg/dL) to a peak of 11.96 ± 0.7 mg/dL at 24 h. The levels of inorganic phosphate in plasma increased over time from 7.3 ± 0.5 to 8.1 ± 0.8 mg/dL by 6 h and were maintained at a plateau level (9.1 ± 0.7 to 8.6 ± 0.6 mg/dL) from 24 to 96 h after treatment. Plasma magnesium decreased from a baseline level of 2.1 ± 0.1 mg/dL to a plateau level of 1.8 ± 0.1 mg/dL, which was sustained from 24 to 48 h after treatment. The present study provides evidence of the absorption of exogenous 1,25(OH)₂D₃ from the bovine vaginal wall, as shown by the marked elevation of plasma 1,25(OH)₂D₃ levels by 2 h after administration, and indicates the possible utility of intravaginal administration of 1,25(OH)₂D₃ for prophylaxis of hypocalcemia.