Effect of chito-oligosaccharide on the oral absorptions of phenolic acids of Flos Lonicerae extract

Phenolic acids, the main active ingredients in Flos Lonicerae extract possess strong antibacterial, antioxidant and antiviral effects, and their contents was higher largely than that of other ingredients such as flavones, but the absolute bioavailability orally was significantly low, which is significant low influencing clinical efficacies of its oral preparations. In the present study, in vitro Caco-2 cell, in situ single-pass intestinal perfusion and in vivo pharmacokinetics study were performed to investigate the effects of COS on the intestinal absorption of phenolic acids. The pharmacological effects such as antiviral activity improvement by COS were verified by MDCK cell damage inhibition rate after influenza virus propagation. The observations from in vitro Caco-2 cell showed that the absorption of phenolic acids in Flos Lonicerae extract could be improved by COS. Meanwhile, COS at the same low, medium and high concentrations caused a significant, concentration-dependent increase in the P_app-value for phenolic acids compared to the control group (p < 0.05), and was all safe for the Caco-2 cells. The observations from single-pass intestinal perfusion in situ model showed that the intestinal absorption of phenolic acids can be enhanced by COS. Meanwhile, the absorption enhancing effect of phenolic acids might be saturable in different intestine sites. In pharmacokinetics study, COS at dosage of 25 mg/kg improved the bioavailability of phenolic acids in Flos Lonicerae extract to the greatest extent, and was safe for gastrointestine from morphological observation. Besides, treatment with Flos Lonicerae extract with COS at dosage of 25 mg/kg prevented MDCK cell damage upon influenza virus propagation better than that of control. All findings above suggested that COS at dosage of 25 mg/kg might be safe and effective absorption enhancer for improving the bioavailability of phenolic acids and the antiviral activity in vitro in Flos Lonicerae extract.     

Acylated phenylethanoid oligoglycosides with hepatoprotective activity from the desert plant Cistanche tubulosa

The methanolic extract from fresh stems of Cistanche tubulosa (Orobanchaceae) was found to show hepatoprotective effects against d-galactosamine (d-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. From the extract, three new phenylethanoid oligoglycosides, kankanosides H₁ (1), H₂ (2), and I (3), were isolated together with 16 phenylethanoid glycosides (4–19) and two acylated oligosugars (20, 21). The structures of 1–3 were determined on the basis of spectroscopic properties as well as of chemical evidence. Among the isolates, echinacoside (4, IC₅₀ = 10.2 μM), acteoside (5, 4.6 μM), isoacteoside (6, 5.3 μM), 2′-acetylacteoside (8, 4.8 μM), and tubuloside A (10, 8.6 μM) inhibited d-GalN-induced death of hepatocytes. These five isolates, 4 (31.1 μM), 5 (17.8 μM), 6 (22.7 μM), 8 (25.7 μM), and 10 (23.2 μM), and cistantubuloside B₁ (11, 21.4 μM) also reduced TNF-α-induced cytotoxicity in L929 cells. Moreover, principal constituents (4–6) exhibited in vivo hepatoprotective effects at doses of 25–100 mg/kg, po.     

Improved accumulation of phenylethanoid glycosides by precursor feeding to suspension culture of Cistanche salsa

Effects of some precursors on phenylethanoid glycosides (PeGs) accumulation in Cistanche salsa cell suspension cultures were investigated. Precursors such as tyrosine, phenylalanine, caffeic acid and cucumber juice at proper concentrations could increase the total accumulation of PeGs (echinacoside, acteoside, 2′-acetylacteoside) by 50%, 12%, 12% and 23%, respectively. Under the combined feeding of precursors at proper concentrations, the total production of PeGs in bio-staged culture reached the highest amount of 1358.1 mg l⁻¹ (640.8 mg echinacoside l⁻¹, 689.4 mg acteoside l⁻¹ and 54.9 mg 2′-acetylacteoside l⁻¹), which was about two-fold of that in the control. This study showed promise for obtaining large-scale production of active ingredients in plant cells by the solid–liquid two step culture (SLTSC) technique and also provided for the first time an example for producing PeGs by C. salsa cell culture. The improved production of PeGs was higher than that in previous reports on PeG production by Cistanche deserticola cell culture fed with precursors.     

Unusual new phenylethanoid and phenylpropanoid diglycosides from the leaves of Chloranthus spicatus (Thunb.) Makino

Chloranthus spicatus (Thunb.) Makino (Chloranthaceae) has been used to treat aches, trauma, and bleeding in Traditional Chinese Medicine. Phytochemical investigation of the leaves of this plant led to the isolation an unusual new phenylethanoid diglycoside, spicaoside (1), and a new phenylpropanoid diglycoside, 1-allyl-3-methoxy-4- [apiofuranosyl(1 ⿿ 2)-glucopyranosyloxybenzene] (2), along with two known sesquiterpenoid glycosides, chloranoside A (3) and chloranthalactone E 8-O-β-d-glucopyranoside (4). Their structures were established by spectroscopic means. New compounds 1 and 2 showed moderate tyrosinase inhibitory activities with the IC₅₀ value of 15.4 μM and 29.1 μM. This study represents the first report of glycoside from C. spicatus.     

Antiviral efficacy of Limonium densiflorum against HSV-1 and influenza viruses

Viral infections remain a major threat to humans and animals and there is a crucial need for new antiviral agents especially with the development of resistant viruses. Several Limonium genus members (Plumbaginacea) have been widely used in traditional medicine for the treatment of infections. In this study, we investigated the antiviral activities of different fractions after successive extraction (hexane, dichloromethane, ethanol and methanol) of the halophyte Limonium densiflorum against H1N1 influenza and HSV-1 herpes viruses. In addition, TLC phytochemicals of the shoot extracts were analyzed. All extracts were tested for their cytotoxicity using a fluorometric resazurin assay. The antiviral activity of extracts was tested using four modes of action: virucidal test, pretreatment of cells with samples before infection, attachment assay and plaque reduction test. A good antiviral activity was found with ethanol and methanol extracts. They were most potent in HSV-1 inhibition than H1N1 influenza virus. The most potent inhibition was observed with ethanol extract, and it exhibited high levels of virucidal activity against HSV-1 (IC₅₀ = 6 μg/mL). It inhibits the replication of the virus by 75% when added after penetration of the virus, and by 100% when added during the viral attachment. It protects MDCK cells against influenza virus by abolishing virus to entry into the host cell (IC₅₀ = 55 μg/mL). After attachment of influenza virus, the ethanol extract displayed an appreciable inhibition of virus replication (IC₅₀ = 193 μg/mL). Methanol extract showed a moderate antiviral capacity against both viruses. While dichloromethane has excellent antiherpes potential, results were inappropriate because it was toxic to Vero cells, hexane extract has no effect. TLC analysis of these extracts showed that flavonoids and saponins were the major classes of natural products found in the shoot extracts that may be responsible for these antiviral activities.     

Synthesis and pharmacological evaluation of nucleoside prodrugs designed to target siderophore biosynthesis in Mycobacterium tuberculosis

The nucleoside antibiotic, 5′-O-[N-(salicyl)sulfamoyl]adenosine (1), possesses potent whole-cell activity against Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis (TB). This compound is also active in vivo, but suffers from poor drug disposition properties that result in poor bioavailability and rapid clearance. The synthesis and evaluation of a systematic series of lipophilic ester prodrugs containing linear and α-branched alkanoyl groups from two to twelve carbons at the 3′-position of a 2′-fluorinated analog of 1 is reported with the goal to improve oral bioavailability. The prodrugs were stable in simulated gastric fluid (pH 1.2) and under physiological conditions (pH 7.4). The prodrugs were also remarkably stable in mouse, rat, and human serum (relative serum stability: human ∼ rat ≫ mouse) displaying a parabolic trend in the SAR with hydrolysis rates increasing with chain length up to eight carbons (t_1/2 = 1.6 h for octanoyl prodrug 7 in mouse serum) and then decreasing again with higher chain lengths. The permeability of the prodrugs was also assessed in a Caco-2 cell transwell model. All of the prodrugs were found to have reduced permeation in the apical-to-basolateral direction and enhanced permeation in the basolateral-to-apical direction relative to the parent compound 2, resulting in efflux ratios 5–28 times greater than 2. Additionally, Caco-2 cells were found to hydrolyze the prodrugs with SAR mirroring the serum stability results and a preference for hydrolysis on the apical side. Taken together, these results suggest that the described prodrug strategy will lead to lower than expected oral bioavailability of 2 and highlight the contribution of intestinal esterases for prodrug hydrolysis.     

Phenylethanoid glycosides from the leaves of Magnolia hodgsonii

Three new phenylethanoid glycosides, 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside A, 1), 2-(3-hydroxy-4-methoxyphenyl)ethyl 1-O-β-d-glucopyranosyl-(1 → 4)-β-d-allopyranoside (hodgsonialloside B, 2) and 2-(3-methoxy-4-hydroxyphenyl)ethyl 1-O-β-d-allopyranoside (hodgsonialloside C, 3) were isolated from the leaves of Magnolia hodgsonii in addition to six known compounds, tyrosol 4-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranoside (4), kaempferol 3-O-neohesperidoside (5), kaempferol 3-O-rutinoside (6), kaempferol 3-O-α-l-rhamnopyranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside (7), (+)-syringaresinol O-β-d-glucopyranoside (8), and oblongionoside C (9). The structure elucidation of these compounds was based on analyses of physical and spectroscopic data including 1D and 2D NMR experiments.     

Detoxification of aflatoxin B1 by an aqueous extract from leaves of Adhatoda vasica Nees

The effectiveness of aqueous extracts of various medicinal plants in detoxification of aflatoxin B1 (AFB1) was tested in vitro by thin-layer chromatography and enzyme-linked immunosorbent assay (ELISA). Among the different plant extracts, the leaf extract of Vasaka (Adhatoda vasica Nees) showed the maximum degradation of AFB1 (≥98%) after incubation for 24 h at 37 °C. The aflatoxin detoxifying activity of the A. vasica leaf extract was significantly reduced by heating to 100 °C for 10 min or autoclaving at 121 °C for 20 min. Dialysis had no effect on aflatoxin detoxifying ability of A. vasica extract and the dialyzed extract showed similar level of detoxification of AFB1 as that of the untreated extract. A time course study of aflatoxin detoxification by A. vasica extract showed that 69% of the toxin was degraded within 6 h and ≥95% degradation was observed after 24 h of incubation. Detoxification of AFB1 by A. vasica extract was further confirmed by liquid chromatography–mass spectrometry (LC–MS) analysis. Phytochemical analysis revealed the presence of alkaloids in methanolic extract of A. vasica leaves. A partially purified alkaloid from A. vasica leaves by preparative TLC exhibited strong AFB1 detoxification activity.     

Acylated pregnane glycosides from Caralluma quadrangula

In a previous study, the methanolic extract as well as the chloroform fraction of the aerial parts of Caralluma quadrangula (Forssk.) N.E.Br. indigenous to Saudi Arabia showed significant in vitro cytotoxic activity against breast cancer (MCF7) cell line. In a biologically-guided fractionation approach, four acylated pregnane glycosides were isolated from the chloroform fraction of C. quadrangula. The structures of the isolated compounds were elucidated by the analysis of their MS and NMR data. The compounds were identified as 12,20-di-O-benzoylboucerin 3-O-β-d-digitoxopyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-cymaropyranoside (1), 12,20-di-O-benzoylboucerin 3-O-β-d-cymaropyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-cymaropyranoside (2), 12,20-di-O-benzoylboucerin 3-O-β-d-glucopyranosyl-(1 → 4)-β-d-digitoxopyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-cymaropyranoside (3) and 12,20-di-O-benzoyl-3β,5α,12β,14β,20-pentahydroxy-(20R)-pregn-6-ene 3-O-β-d-glucopyranosyl-(1 → 4)-β-d-digitoxopyranosyl-(1 → 4)-β-d-canaropyranosyl-(1 → 4)-β-d-cymaropyranoside (4). The isolated compounds were tested for their cytotoxic activity against breast cancer (MCF7) cell line.     

Momordicatin purified from fruits of Momordica charantia is effective to act as a potent antileishmania agent

Aqueous extract of the green fruits of the Indian plant Momordica charantia and purified Momordicatin structurally established as 4-(o-carboethoxyphenyl) butanol were evaluated in vitro and in vivo against kala-azar caused by Leishmania donovani. 50% inhibitory concentration (IC₅₀) against Leishmania promastigotes in vitro for the crude extract and momordicatin were 0.6 mg/L and 0.02 mg/L, respectively. When administered in the hamster model of visceral leishmaniasis, 100% parasite clearance was achieved at a dose of 300 mg/kg body weight of crude extract and 10 mg/kg body weight of Momordicatin. Fe containing parasite superoxide dismutase (SOD) was totally inhibited when treated with 0.72 mg/L crude extract and 0.20 mg/L Momordicatin, respectively, whereas Cu–Zn containing SOD present in host remained unaffected. Results reveal that the mode of action of these newly found antileishmanial agents is mediated through inhibiting parasite SOD which is one of the key enzymes of the oxidative burst. It may be proposed from the present study that both crude extract of Momordica charantia and Momordicatin obtained from the fruits of the said plant may be considered as potential candidates towards developing new chemotherapeutics against leishmaniasis.     

Green synthesis of silver nanoparticles with Dalbergia spinosa leaves and their applications in biological and catalytic activities

The phytosynthesis of silver nanoparticles (AgNPs) by Dalbergia spinosa leaves (DSL) in aqueous extract was investigated. AgNPs were characterized by UV–visible absorption spectroscopy (UV–vis), transmission electron microscopy (TEM) and Fourier transform infra red spectrophotometry (FTIR). The results showed that the increase in the initial extract concentration at room temperature increased the mean size and widened the size distribution of the AgNPs, leading to a red shift and broadening the surface plasmon resonance absorption (439 nm). The results showed that the reducing sugars and flavonoids were primarily responsible for the bioreduction of silver ions and that their reductive capability was promoted at 36 °C. TEM analysis showed that the AgNPs were nearly spherical in shape with an average size of 18 ± 4 nm. When evaluated for in vitro antioxidant activity by DPPH, NO, hydrogen peroxide radicals, reducing power and CUPRAC assay methods in addition to anti-inflammatory activity by HBRC method, the silver nanoparticles exhibited considerably enhanced antioxidant and anti-inflammatory activity at the test doses when compared with that of the standards and the plant extract. Finally, the antibacterial activity of the AgNPs against two Gram-positive bacteria and two Gram-negative bacteria showed moderate antibacterial activity when compared with the standard and the plant extract. The synthesized silver nanoparticles were also effective in the catalytic reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP).     

Antimicrobial activity of medicinal plants and induction of defense related compounds in banana fruits cv. Robusta against crown rot pathogens

A total of 72 plant extracts were tested in vitro for their ability to inhibit the mycelial growth of Lasiodiplodia theobromae and Colletotrichum musae the causal agents of crown rot disease of banana. The results showed that the leaf extract of Zimmu (an interspecific hybrid of Allium cepa L. × Allium sativum L.) and tuber extract of Zehneria scabra recorded maximum inhibition of mycelial growth and spore germination of both the test pathogens. The dipping of banana fruits in Zimmu leaf extract at 25% conc. exhibited 100% inhibition of crown rot disease in cold storage (14 °C) up to 35 days and increased the shelf life to 64 days. However, at room storage (28 ± 2 °C), the same treatment exhibited 86% inhibition of crown rot disease up to 12 days. It was found that the treatment of banana fruits with Zimmu leaf extract did not alter the organoleptic properties of banana. The biochemical analysis of banana fruits treated with Zimmu leaf extract showed significant increase in phenylalanine ammonia-lyase (PAL), chitinase and β-1,3-glucanase activities and enhanced accumulation of phenolic compounds compared to other treatments. These findings suggest that the effect of Zimmu leaf extract on crown rot disease may be associated with the direct fungi toxic property against the test pathogens and elicitation of defense related compounds in banana fruits.     

Antioxidant, α-amylase inhibitory and oxidative DNA damage protective property of Boerhaavia diffusa (Linn.) root

Boerhaavia diffusa Linn. of family Nyctaginaceae is a known traditional medicinal plant and has been used in the treatment of many free radical mediated diseases. Excessive formation of free radicals, either reactive oxygen species (ROS) or reactive nitrogen species (RNS) is responsible for damaging various biomolecules like DNA, lipids and proteins. The present investigation was initially carried out to explore the possible link between antioxidant, oxidative DNA damage protective and α-amylase inhibitory property of B. diffusa root extract and their bioactive fraction. Our results illustrated an enhanced DPPH radical scavenging activity/antioxidant power of methanol root extract (IC₅₀ < 250 μg/ml) than ethanol (IC₅₀ = 250 μg/ml) and aqueous extract (IC₅₀ > 250 μg/ml). In addition, the methanol root extract also showed better oxidative DNA damage protective activity and α-amylase inhibitory property than ethanol and aqueous root extract. Phytochemical screening of B. diffusa ethanol and methanol root extract showed the presence of saponins, alkaloids, flavonoids, glycosides and terpenoids in large amount. By means of repetitive preparatory TLC and HPLC the potent antioxidant and α-amylase inhibitory fraction was isolated from methanol root extract. Our results illustrated that DPPH radical scavenging activity (IC₅₀ < 250 μg/ml) and oxidative DNA damage protective and α-amylase inhibitory activity of the isolated/purified bioactive compound from methanol extract were significantly closer to that of crude extract, which in turn confirm that antioxidant and antidiabetic property of methanol root extract resides in this fraction and established a significant correlation between antioxidant and inhibitory α-amylase property of this bioactive fraction compound. These profound effects of B. diffusa methanol root extract and its purified fraction against oxidative plasmid DNA damage, antioxidant and α-amylase inhibitory activity may explain its extensive use in daily life and possible health benefits.     

A lipase inhibitor monoterpene and monoterpene glycosides from Monarda punctata

An 80% acetone extract of Monarda punctata showed an inhibitory effect on lipase activity in isolated mouse plasma in vitro and carvacrol was obtained as the active constituent. It had an IC₅₀ value of 4.07 mM in vitro and suppressed elevations in blood triacylglycerol levels in olive oil-loaded mice. Furthermore, from the whole plant, 22 compounds were isolated. Six monoterpene glycosides (3–8), a flavone glucuronide (9), and other known compounds were identified based on the results of spectroscopic analyses.     

The hypoglycemic activity of Euclea undulata Thunb. var. myrtina (Ebenaceae) root bark evaluated in a streptozotocin–nicotinamide induced type 2 diabetes rat model

The hypoglycemic activity of a crude acetone extract of the root bark of Euclea undulata var. myrtina was evaluated in a streptozotocin–nicotinamide induced type 2 diabetes rat model after positive results were obtained by in vitro screening of glucose utilization by C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells and alpha-glucosidase inhibition. Thirty male Wistar rats were used for the experiment. Type 2 diabetes was induced by a single intraperitoneal injection of streptozotocin and administration of nicotinamide 15 min after. Animals exhibiting fasting glucose levels of 140–200 mg/dl after 7 days were screened as type 2 diabetes. Extract was administered for 21 days orally at a concentration of 50 mg/kg and 100 mg/kg respectively. Glibenclamide (1 mg/kg) was used as positive control. On day 21, blood lipid profiles and body weight were determined by using standard enzymatic colorimetric kits before the rats were sacrificed by cervical decapitation. The crude acetone extract of E. undulata root bark at a concentration of 100 mg/kg body weight significantly lowered fasting blood glucose levels as well as elevated cholesterol and triglyceride levels to near normal without any weight gain. The results indicate that the crude acetone root bark extract of E. undulata exhibit antidiabetic activity in type 2 induced diabetic rats. It confirms the in vitro screening results as well as its use in the treatment of diabetes by traditional healers and herbalists in southern Africa.     

Synergism of three-drug combinations of sanguinarine and other plant secondary metabolites with digitonin and doxorubicin in multi-drug resistant cancer cells

We determined the ability of some phytochemicals, including alkaloids (glaucine, harmine, and sanguinarine), phenolics (EGCG and thymol), and terpenoids (menthol, aromadendrene, β-sitosterol-O-glucoside, and β-carotene), alone or in combination with the saponin digitonin to reverse the relative multi-drug resistance of Caco-2 and CEM/ADR5000 cells to the chemotherapeutical agent doxorubicin. The IC₅₀ of doxorubicin in Caco-2 and CEM/ADR5000 was 4.22 and 44.08 μM, respectively. Combination of non-toxic concentrations of individual secondary metabolite with doxorubicin synergistically sensitized Caco-2 and CEM/ADR5000 cells, and significantly enhanced the cytotoxicity of doxorubicin. Furthermore, three-drug combinations (secondary metabolite + digitonin + doxorubicin) were even more powerful. The best synergist was the benzophenanthridine alkaloid sanguinarine. It reduced the IC₅₀ value of doxorubicin 17.58-fold in two-drug combinations (sanguinarine + doxorubicin) and even 35.17-fold in three-drug combinations (sanguinarine + digitonin + doxorubicin) in Caco-2 cells. Thus synergistic drug combinations offer the possibility to enhance doxorubicin efficacy in chemotherapy.     

Free radical scavenging activity from different extracts of leaves of Bauhinia vahlii Wight & Arn.

The objectives of this study were to determine phenolic content and antioxidant activities of chloroform, acetone, methanol and hot water extracts of Bauhinia vahlii leaves. The hot water extract afforded the highest yield (6.3%) while the lowest yield was obtained from the chloroform extract (2.1%). The methanol extract contains higher levels of total phenolics (48.7 ± 0.7 g GAE/100 g extract), tannins (21.7 ± 0.7 g GAE/100 g extract) and flavonoids (10.3 ± 0.2 RE/100 g extract). The extracts were subjected to assess their antioxidant potential using various in vitro systems such as DPPH, ABTS⁺, FRAP, OH, β-carotene linoleic acid bleaching system, phosphomolybdenum reduction and Fe²⁺ chelation. It is concluded that the methanolic extract of B. vahlii leaves have strong antioxidant potential. Further study is necessary for isolation and characterization of the active antioxidants, which may serve as a potential source of natural antioxidants.     

The use of herbs against neglected diseases: Evaluation of in vitro leishmanicidal and trypanocidal activity of Stryphnodendron rotundifolium Mart

The evaluation of the leishmanicidal and trypanocidal activity of the hydroalcoholic extract of the bark of Stryphnodendron rotundifolium Mart. (EHCSR) was carried out to find an alternative treatment for parasitic diseases. EHCSR was prepared and used at four different concentrations (1000, 500, 250, 125 μg/mL) in in vitro assays for activity against Leishmania promastigotes using the species Leishmania brasiliensis and Leishmania infantum and for trypanocidal activity using the epimastigotes of Trypanosoma cruzi. We also tested EHCSR for cytotoxicity against adhered cultured Murine J774 fibroblasts. The tests were performed in triplicate, and the percent mortality of parasites, IC₅₀ and percent toxicity were determined. With regard to anti-leishmania activity against L. infantum, there was a mean mortality of 45% at all concentrations, and against L. brasiliensis, a substantial effect was seen at 1000 μg/mL with 56.38% mortality, where the IC₅₀ values were 1338.76 and 987.35 μg/mL, respectively. Trypanocidal activity was notably high at 1000 μg/mL extract with 82.31% mortality of epimastigotes. Cytotoxicity at the highest extract concentrations of 500 and 1000 μg/mL was respectively 75.12% and 94.14%, with IC₅₀ = 190.24 μg/mL. Despite that the extract has anti-parasitic activity, its substantial cytotoxicity against fibroblasts cells makes its systemic use nonviable as a therapeutic alternative.     

Effect of phytic acid,tannic acid and pectin on fasting iron bioavailability both in the presence and absence of calcium

ObjectiveTo determine the effect of phytic acid, tannic acid and pectin on fasting non-heme iron bioavailability in both the presence and absence of calcium.Research methodsTwenty-eight apparently healthy adult females participated in two iron absorption studies using radioactive iron isotopes (⁵⁹Fe and ⁵⁵Fe). One group received 5 mg of iron (as FeSO₄) alone (control), together with 10 mg of phytic acid, 100 mg of tannic acid and 250 mg of pectin (study A), on different days. The second group received the same iron doses and compounds as the other group, plus 800 mg of calcium (CaCl₂) (study B). The compounds were administered after an overnight fast, and no food or beverages were consumed for the following 3 h. Iron status and circulating radioactivity were measured in venous blood samples.ResultsThe geometric means of iron bioavailability (range ± 1SD) for iron alone, iron with phytic acid, iron with tannic acid, and iron with citrus pectin were 25.0% (11.9–52.0); 18.9% (9.9–35.8); 16.8% (8.7–32.3); and 21.1% (10.2–43.9), respectively (repeated-measures ANOVA, p < 0.02 (Dunnett's post hoc: control vs tannic acid p < 0.05). When 800 mg of calcium was added (study B), iron bioavailability was 16.7% (10.1–27.5); 13.2% (7.1–24.6); 14.8% (8.8–25.1); and 12.6% (5.5–28.8), respectively (repeated-measures ANOVA, NS).ConclusionsTannic acid decreases the fasting bioavailability of non-heme iron, however this effect did not exist in the presence of calcium. No effect was observed by phytic acid or citrus pectin on fasting non-heme iron bioavailability in both the presence and absence of calcium.     

Evaluation of in vitro free radical scavenging potential of Streptomyces sp. AM-S1 culture filtrate

The present study was carried out to determine the free radical scavenging potential of culture filtrate of Streptomyces sp. AM-S1. Antioxidant activity of culture filtrate, lyophilized culture filtrate and ethyl acetate extract of Streptomyces sp. AM-S1 was determined by various in vitro assays such as ferric reducing power assay, phosphomolybdenum reduction, DPPH and ABTS radical scavenging activities. The results revealed that the culture filtrate of Streptomyces sp. AM-S1 effectively scavenged DPPH (IC₅₀ 90.2 μl/ml) and ABTS (IC₅₀ 13.2 μl/ml) radicals in a concentration dependent manner. In all the assays, ethyl acetate extract registered higher antioxidant activity when compared with the lyophilized culture filtrate (LCF). In addition, ethyl acetate extract (1123.4 μmole Fe(II)/mg extract) exhibited higher ferric reducing activity than the standard BHA (814.4 μmole Fe(II)/mg extract). Further works are needed on the isolation and identification of antioxidant molecules from the ethyl acetate extract of Streptomyces sp. AM-S1 culture filtrate.