Krameria Lappacea Research Articles

Utilization of azamacrocyclic ionophores as recognition elements for the potentiometric determination of gallic acid in various matrices

Gallic acid is a naturally occurring low molecular weight triphenolic molecule identified as a potent antioxidant, protecting against various types of reactive species and non-radicals. Three novel carbon paste electrodes were developed for the potentiometric determination of gallic acid. Azamacrocyclic ionophors; cyclen, hexacyclen, and kryptofix-22 were utilized as recognition ionophores separately. A multi-walled carbon nanotubes/titanium oxide nanocomposite was employed as the ion-to-electron transducer in the designed sensors. The prepared transducer was characterized by FT-IR and TEM. Molecular docking was implemented to study the recognition mechanism between these ionophores and the gallic acid molecule. It revealed promising binding interactions between gallic acid and the three recognition ionophores, especially hexacyclen and Kryptofix-22. In studying the potentiometric response of the proposed sensors, they exhibited high stability, sensitivity, accuracy, and precision in the quantitation of gallic acid. Gallic acid can be accurately quantified over the linearity range of 1 × 10−1–1 × 10−3 M, 1 × 10−2–1 × 10−6 M, and 1 × 10−2–1 × 10−6 M with a Limit of detection (LOD) 4 × 10−4 M, 3 × 10−7 M, and 7 × 10−7 M, for CPE1, CPE 2 and CPE 3, respectively. The electrodes showed high efficiency in determining gallic acid in Krameria lappacea root alcoholic extract, black tea, green tea, and human plasma without sophisticated pretreatment steps.

Anticoccidial and jejunum-protective effects of Krameria lappacea roots extract on experimental Eimeria papillata infection.

Coccidiosis is a protozoan parasitic disease caused by Eimeria species and affects wild and domestic animals. Coccidiostats are currently available to control this disease, although drug resistance has been confirmed for all of them. As a result, there is an urgent need to identify eco-friendly agents to control and treat this disease. This study aimed to investigate the ameliorative role of the Krameria lappacea roots extract (KLRE) on the outcome of coccidiosis induced by Eimeria papillata. Male C57BL/6 mice were divided into seven groups (5 mice/group), as follows: Group 1: noninfected-nontreated (control group), Group 2: noninfected-treated group with KLRE (200 mg/kg), Group 3: infected-nontreated group, Group 4: infected-treated group with KLRE (50 mg/kg), Group 5: infected-treated group with KLRE (100 mg/kg), Group 6: infected-treated group with KLRE (200 mg/kg), and Group 7: infected-treated group with amprolium (120 mg/kg). Groups (3-7) were inoculated orally with 1 × 103 sporulated E. papillata oocysts. One hour after infection, groups (4-6) were daily treated for 5 days with KLRE and amprolium. On day 5 postinfection, oocyst output was determined, and mice were euthanized for the collection of jejuna then preparation of histological sections and jejunal homogenate was used for the determination of biochemical and oxidative damage markers. The coccidial infection induced weight loss of mice by 3.971%, which improved after KLRE to -1.512%. After KLRE treatment, the rate of feed intake was improved to be 52.21 ± 2.30 than those in infected group (40.47 ± 2.25). Oocyst output was significantly reduced in mice treated with KLRE (1.308 × 106 oocysts/g.feces) compared with those in the infected group (5.387 × 106 oocysts/g.feces). E. papillata infection induced marked histological alterations within jejunum tissue. After treatment, KLRE was able to impair the development of parasite stages (meronts, gamonts, and developing oocysts) in the jejunum through a significant reduction of number and size in comparison with the infected group. Infection with E. papillata induced a disturbance in the nutrient absorption in the jejunal mice tissue, which improved after the treatment with KLRE and amprolium. Also, KLRE counteracted significantly the E. papillata-induced loss of reduced glutathione and total antioxidant capacity. Our findings indicate that KLRE could be used as an alternative to the available coccidiostats currently available. RESEARCH HIGHLIGHTS: Krameria lappacea exhibit significant anticoccidial and antioxidant activities induced by E. papillata infection. Krameria lappacea exhibit significant improvement in the pathological alterations of the jejunal tissue induced by E. papillata infection.

Krameria lappacea root extract's anticoccidial properties and coordinated control of CD4 T cells for IL-10 production and antioxidant monitoring.

Recently, the use of botanicals as an alternative to coccidiostats has been an appealing approach for controlling coccidiosis. Therefore, this study was conducted to evaluate the potential role of aqueous methanolic extract (200 mg/kg) of Krameria lappacea (roots) (KLRE) against infection induced by Eimeria papillata. A total of 25 male C57BL/6 mice were divided into five groups (I, II, III, IV, and V). On 1st day of the experiment, all groups except groups I (control) and II (non-infected-treated group with KLRE), were inoculated orally with 103 sporulated E. papillata oocysts. On the day of infection, group IV was treated with KLRE. Group V served as an infected-treated group and was treated with amprolium (coccidiostat). Treatment with extract and coccidiostat was continued for five consecutive days. While not reaching the efficacy level of the reference drug (amprolium), KLRE exhibited notable anticoccidial activity as assessed by key criteria, including oocyst suppression rate, total parasitic stages, and maintenance of nutrient homeostasis. The presence of phenolic and flavonoid compounds in KLRE is thought to be responsible for its positive effects. The Eimeria infection increased the oxidative damage in the jejunum. KLRE treatment significantly increased the activity of catalase and superoxide dismutase. On the contrary, KLRE decreased the level of malondialdehyde and nitric oxide. Moreover, KLRE treatment decreased macrophage infiltration in the mice jejunal tissue, as well as the extent of CD4 T cells and NFkB. E. papillata caused a state of systemic inflammatory response as revealed by the upregulation of inducible nitric oxide synthase (iNOs)-mRNA. Upon treatment with KLRE, the activity of iNOs was reduced from 3.63 to 1.46 fold. Moreover, KLRE was able to downregulate the expression of pro-inflammatory cytokines interferon-γ, nuclear factor kappa B, and interleukin-10 -mRNA by 1.63, 1.64, and 1.38 fold, respectively. Moreover, KLRE showed a significant reduction in the expression of IL-10 protein level from 104.27 ± 8.41 pg/ml to 62.18 ± 3.63 pg/ml. Collectively, K. lappacea is a promising herbal medicine that could ameliorate the oxidative stress and inflammation of jejunum, induced by E. papillata infection in mice.

Chemical Profile and Biological Effects of an Herbal Mixture for the Development of an Oil-in-Water Cream.

Three individual hydroalcoholic extracts derived from Hamamelis virginiana leaves, Krameria lappacea root, Salix alba bark, and the resulting herbal mixture (HM) were assessed for the phytochemical profile as well as for antibacterial and cytotoxic potential. The chemical composition of the individual extracts and of their mixture was analyzed by chromatographical (LC-MS) and spectrophotometrical methods. The antimicrobial properties were evaluated by using the agar-well diffusion and the broth microdilution assays, whereas the potential cytotoxicity was investigated on human keratinocyte cell line by MTT method and apoptosis test. The HM composition revealed important amounts of valuable polyphenolic compounds provided from the individual extracts, having synergistic biological effects. All tested extracts displayed in vitro antimicrobial properties, with a significantly higher efficacy noticed for the HM when tested against Staphylococcus aureus. Moreover, none of the tested extracts was responsible for in vitro cytotoxicity against the human keratinocytes in the selected concentration range. Furthermore, the HM was included in an oil-in-water cream for the nonpharmacological treatment of seborrheic dermatitis, developed and optimized by using a QbD approach. A D-optimal experimental plan with four factors that varied on two levels was used to investigate the effect of the quantitative variation of the formulation factors (emulsifier, co-emulsifier, thickening agent, oily phase ratio) on the characteristics of the cream in terms of firmness, consistency, adhesiveness, stringiness, spreadability, and viscosity. Based on the experimental results, an optimal formulation containing 2.5% emulsifier and 20% oily phase was prepared and analyzed. The obtained results showed appropriate quality characteristics of this novel cream, which may be used in the future to manage the associated symptoms of seborrheic dermatitis.

Anticancer efficacies of Krameria lappacea extracts against human breast cancer cell line (MCF-7): Role of oxidative stress and ROS generation

Breast cancer is a growing health issue globally and accounts as a second most cause of mortality. Natural products have been a fundamental of health care for long. Plants derived natural products have gained considerable attention over synthetic medicines, since they are safe and non-toxic. Krameria lappacea (Dombey) Burdet and B.B. Simpson plant belonging to Krameriaceae family, has been known for its beneficial effects against diseases. Herein, firstly, cytotoxic potential of petroleum ether (KLH), chloroform (KLC), ethyl acetate (KLEA), and ethanolic (KLET) extracts of K. lappacea was screened against MCF-7 cells exposed to 10–1000 μg/mL for 24 h. Secondly, the most cytotoxic extract (KLH) was used to explore the mechanisms of cytotoxicity in MCF-7 cells. MCF-7 cells were treated with KLH at 250–1000 μg/mL to measure the oxidative stress markers (glutathione (GSH) and lipid peroxidation (LPO)) and reactive oxygen species (ROS) generation. Further, loss of mitochondrial membrane potential (MMP) and caspase-3 and -9 enzyme activities were studied. The viability of MCF-7 cells were decreased from 44% to 90% for KLH, from 7% to 71% for KLEA, from 39% to 80% for KLC, and from 3% to 81% for KLET, respectively at 250–1000 μg/mL as observed by MTT assay. An increase of 91% in LPO and 2.2-fold in ROS generation and a decrease of 59% in GSH and 68% in MMP levels at 1000 μg/mL showed that KLH induced MCF-7 cell death via oxidative stress and elevated level of ROS generation which further leads to mitochondrial membrane dysfunction and activation of caspase enzymes. The findings of this study provide a mechanistic insight on anticancer efficacies of K. lappacea extracts against MCF-7 cells and support the use of it for the treatment of breast cancer diseases.

Comparative Antimicrobial Effect of Boswellia, Lichen, Coffea peel, Asafoetida, Saussurea Costus, Rhatany, Anise and Cumin Extracts on Some Animal Pathogens

Numerous plants have so far been utilized for the treatment and the executives of different illnesses since the start of human development. One of the regular issues in the clinical world, spreading of bacterial opposition against anti-infection agents, so one of the most significant strides in microbiological investigates is to locate another antimicrobial compound with insignificant reactions. Because of the nearness of organic dynamic mixes in plant and herbs and its utilization in conventional Objective medication and sustenance, it appears that this plants and herbs contain limit significant antimicrobial. So the aim of this study is to explore the antimicrobial action of Boswellia, Lichen, Coffea peel, Rhatany (Krameria triandra), Cuminum cyminum, Pimpinella anisum, Asafoetida, and Saussurea costus aqueous and solvent extracts on some therapeutically significant bacteria and fungi isolated from animals. Hot and cold aqueous extracts in addition to alcohol extracts of Boswellia, Lichen, Coffea peel, Rhatany (Krameria triandra), Cuminum cyminum, Pimpinella anisum , Asafoetida,and Saussurea costus were assessed for their antimicrobial effect against Streptococcus, Escherichia coli Salmonella, klebsiella and Candida albicans by agar well diffusion method. Every single examined plants and herbs indicated antibacterial impact against examined pathogenic microscopic organisms particularly Rhatany, Asafoetida, Lichen, and Pimpinella anisum. The lesser impact was for Coffea peel. Also the most antifungal action against Candida albican swas for Rhatany. For the most part the viable concentrate was the cold aqueous extract for all analyzed plants and herbs.

Bioguided identification of triterpenoids and neolignans as bioactive compounds from anti-infectious medicinal plants of the Taira Atacama's community (Calama, Chile)

Ethnopharmacological relevancePrevious ethnobotanical surveys from the north Andean part of Chile, where different ethnic groups are co-existing, with the preeminence of Aymara and Atacama traditions, revealed an extensive domestic use of the local flora. In these communities, traditional medicinal uses are mainly related to the treatment of respiratory, gastro-intestinal and urinary disorders, pain and inflammation, which is closely linked to epidemiological observations. Aim of the studyAs these symptoms may be related to infectious diseases, a bioguided evaluation of antibacterial and antifungal activity was conducted on eighteen species selected with the Taira community, in Ollague. Materials and methodsScreening was performed using a large panel of pathogenic germs involved in the main community acquired infectious diseases, represented by Gram positive and Gram negative bacteria of clinical interest and by human pathogenic fungi, using a bioguided approach. Results and conclusionsGram positive strains of clinical interest were highly sensitive to Aloysia deserticola (Verbenaceae) and Krameria lappacea (Krameriaceae) extracts. The bioguided approach led us to identify the isolated neolignan from K. lappacea conocarpan (1), and triterpenoids form A. deserticola (oleanolic acid (6) and ursolic acid (10)), as the main bioactive compounds.

An endangered hemiparasitic shrub is the only host plant of the little-known Neotropical hairstreak Strymon flavaria (Lepidoptera: Lycaenidae) in the arid Andes

Larval host plants can be the main resource underlying the distribution (including altitudinal ranges) of specialized phytophagous insects such as butterflies. Strymon flavaria (Ureta) (Lepidoptera: Lycaenidae: Theclinae: Eumaeini) is a little-known hairstreak endemic to the arid belt at about 3000–3500 m elevation on the western slopes of the Andes of northern Chile. The hemiparasitic shrub Krameria lappacea (Dombey) Burdet and Simpson is here recorded as the first host plant known for S. flavaria, representing also the first record of the association of a species of Strymon Hubner with the plant family Krameriaceae. Females of S. flavaria lay eggs on flower buds and unripe fruits of K. lappacea; the larva eats mostly these plant organs. Field observations revealed that S. flavaria is a host-specialist hairstreak, since females lay eggs only on K. lappacea. These findings suggest that the altitudinal range of S. flavaria could be the result of its specialized association with K. lappacea, as this shrub is also mostly restricted to elevations above 3000 m in the Andes of northern Chile. The implications of this finding for the ecology and conservation of S. flavaria are discussed.

Antiproliferative activity and phenotypic modification induced by selected Peruvian medicinal plants on human hepatocellular carcinoma Hep3B cells

Ethnopharmacological relevanceThe high incidence of human hepatocellular carcinoma (HCC) in Peru and the wide use of medicinal plants in this country led us to study the activity against HCC cells in vitro of somes species used locally against liver and digestive disorders. Materials and methodsEthnopharmacological survey: Medicinal plant species with a strong convergence of use for liver and digestive diseases were collected fresh in the wild or on markets, in two places of Peru: Chiclayo (Lambayeque department, Chiclayo province) and Huaraz (Ancash department, Huaraz province). Altogether 51 species were collected and 61 ethanol extracts were prepared to be tested.Biological assessment: All extracts were first assessed against the HCC cell line Hep3B according a 3-step multi-parametric phenotypic assay. It included 1) the evaluation of phenotypic changes on cells by light microscopy, 2) the measurement of the antiproliferative activity and 3) the analysis of the cytoskeleton and mitosis by immunofluorescence. Best extracts were further assessed against other HCC cell lines HepG2, PLC/PRF/5 and SNU-182 and their toxicity measured in vitro on primary human hepatocytes. ResultsEthnopharmacological survey: Some of the species collected had a high reputation spreading over the surveyed locations for treating liver problems, i.e. Baccharis genistelloides, Bejaria aestuans, Centaurium pulchellum, Desmodium molliculum, Dipsacus fullonum, Equisetum bogotense, Gentianella spp., Krameria lapacea, Otholobium spp., Schkuhria pinnata, Taraxacum officinale.Hep3B evaluation: Fourteen extracts from 13 species (Achyrocline alata, Ambrosia arborescens, Baccharis latifolia, Hypericum laricifolium, Krameria lappacea, Niphidium crassifolium, Ophryosporus chilca, Orthrosanthus chimboracensis, Otholobium pubescens, Passiflora ligularis, Perezia coerulescens, Perezia multiflora and Schkuhria pinnata) showed a significant antiproliferative activity against Hep3B cells (IC50≤ 50µg/mL). This was associated with a lack of toxicity on primary human hepatocytes in vitro. Immunofluorescence experiments on Hep3B cells showed that crude extracts of Schkuhria pinnata and Orthrosanthus chimboracensis could block Hep3B cells in mitosis with an original phenotype. Crude extracts of Perezia coerulescens, Perezia multiflora, Achyrocline alata, Ophryosporus chilca, Otholobium pubescens and Hypericum laricifolium could modify the overall microtubule cytoskeletal dynamics of Hep3B cells in interphase by an original mechanism. ConclusionsOur method allowed us to select 9 extracts which displayed antiproliferative activities associated with original cellular phenotypes on Hep3B cells, regarding known microtubule-targeting drugs. Both chemical and cellular studies are ongoing in order to elucidate natural compounds and cellular mechanisms responsible of the activities described.

2-(2,4-dihydroxyphenyl)-5-(E)-propenylbenzofuran promotes endothelial nitric oxide synthase activity in human endothelial cells

Endothelial nitric oxide synthase (eNOS) mediates important vaso-protective and immunomodulatory effects. Aim of this study was to examine whether lignan derivatives isolated from the roots of the anti-inflammatory medicinal plant Krameria lappacea influence eNOS activity and endothelial nitric oxide (NO) release. The study was performed using cultured human umbilical vein endothelial cells (HUVECs) and HUVEC-derived EA.hy926 cells. Among the eleven isolated compounds only 2-(2,4-dihydroxyphenyl)-5-(E)-propenylbenzofuran (DPPB) was able to increase eNOS enzyme activity.DPPB (1–10μM) treatment for 24h induced a significant and dose-dependent increase in eNOS activity as determined by the [14C]l-arginine/[14C]l-citrulline conversion assay. Immunoblotting studies further revealed a time-dependent DPPB-induced increase in eNOS-Ser1177 and decrease in eNOS-Thr495 phosphorylation, as well as increased AMPK phosphorylation at Thr172, whereas Akt phosphorylation at Ser473 was not affected. Si-RNA-mediated knockdown of AMPK and inhibition of CaMKKβ by STO 609, as well as intracellular Ca2+ chelation by Bapta AM abolished the stimulating effect of DPPB on eNOS-Ser1177 and AMPK-Thr172 phosphorylation. Furthermore, we could show that DPPB increases intracellular Ca2+ concentrations assessed with the fluorescent dye Fluo-3-AM. DPPB enhances eNOS activity and endothelial NO release by raising intracellular Ca2+ levels and increases signaling through a CaMKKβ–AMPK dependent pathway.

Parasitism and haustorium anatomy of Krameria lappacea (Dombey) Burdet & B.B. Simpson (Krameriaceae), an endangered medicinal plant from the Andean deserts

Krameria lappacea (Rhatany or Ratanhia, Krameriaceae) is an endangered, overexploited medicinal plant from the semi-deserts of Andean South America, and is destructively harvested from nature. There are published data on parasitism of Krameria from three North American species, but not on K. lappacea, the only economically important species. The present study investigates the presence or absence of hemiparasitism, host plant range and haustorium morphology/anatomy. The study was carried out at two sites in Peru, Department Arequipa, Prov. Arequipa. Hemiparasitism was confirmed, with 106 haustorical connections to 18 host plant species from 17 genera and 12 plant families observed, nearly doubling the number of host plant species known for Krameria (incl. four additional angiosperm families). Root and haustorium architecture and anatomy were found to be similar to the North American species. K. lappacea is a highly generalistic hemiparasite and host distribution and abundance are likely not limiting factors for Krameria recruitment and establishment. Due to its wide range of host plants K. lappacea likely influences the performance of the bulk of perennial species in its habitat and overcollection affects the overall vegetation. Conservation strategies and adequate management should have high priority because of the likely ecological and known economical importance of this species.

Lignan Derivatives from Krameria lappacea Roots Inhibit Acute Inflammation in Vivo and Pro-inflammatory Mediators in Vitro

The roots of Krameria lappacea are used traditionally against oropharyngeal inflammation. So far, the astringent and antimicrobial properties of its proanthocyanidin constituents are considered to account for the anti-inflammatory effect. The aim of the present study was to characterize pharmacologically a lipophilic extract of K. lappacea roots and several isolated lignan derivatives (1–11) in terms of their putative anti-inflammatory activity. The dichloromethane extract (ID50 77 μg/cm2) as well compounds 1–11 (ID50 0.31–0.60 μmol/cm2) exhibited topical antiedematous properties comparable to those of indomethacin (ID50 0.29 μmol/cm2) in a mouse ear in vivo model. Two of the most potent compounds, 2-(2-hydroxy-4-methoxyphenyl)-5-(3-hydroxypropyl)benzofuran (5) and (+)-conocarpan (7), were studied regarding their time-dependent edema development and leukocyte infiltration up to 48 h after croton oil-induced dermatitis induction, and they showed activity profiles similar to that of hydrocortisone. In vitro studies of the isolated lignan derivatives demonstrated the inhibition of NF-κB, cyclooxygenase-1 and -2, 5-lipoxygenase, and microsomal prostaglandin E2 synthase-1 as well as antioxidant properties, as mechanisms possibly contributing to the observed in vivo effects. The present findings not only support the ethnopharmacological use of K. lappacea roots but also reveal that the isolated lignan derivatives contribute strongly to the anti-inflammatory activity of this herbal drug.

Antioxidant and photoprotective activity of a lipophilic extract containing neolignans from Krameria triandra roots.

The antioxidant/photoprotective potential of a standardized Krameria triandra (KT) root extract (15% neolignans) has been evaluated in different cell models, rat erythrocytes and human keratinocytes cell lines, exposed to chemical (cumene hydroperoxide, CuOOH) and physical (UVB radiation) free radical inducers. The extract was significantly more active (IC50 0.28 +/- 0.04 microg/ml) than the typical chain-breaking antioxidant alpha-tocopherol (IC50 = 6.37 +/- 0.41 microg/ml) in inhibiting the CuOOH-induced hemolysis in rat blood cells. The KT constituent 2-(2,4-dihydroxyphenyl)-5-(E)-propenylbenzofuran, was the most active (IC50 = 0.03 +/- 0.005 microg/ml), followed by eupomatenoid 6 (IC50 = 0.29 +/- 0.06 microg/ml) and conocarpan (IC50 = 0.77 +/- 0.08 microg/ml). The same order of potency was observed in red blood cells exposed to UVB irradiation in continuo, with IC50 values 0.78 +/- 0.08 microg/ml for KT extract, 0.18 +/- 0.02 microg/ml for 2-(2,4-dihydroxyphenyl)-5-(E)-propenylbenzofuran, 0.95 +/- 0.11 microg/ml for eupomatenoid 6, and 3.8 +/- 0.39 microg/ml for conocarpan. In cultured human keratinocytes exposed to UVB radiation (50 mJ/cm2), KT extract (2.5-20 microg/ml) significantly and dose-dependently restrained the loss in cell viability and the intracellular oxidative damage: glutathione (GSH) depletion and the rise in dichlorofluorescein (DCF), marker of peroxide accumulation, were suppressed by 20 microg/ml KT and in parallel cell morphology maintained. The cytoprotective effect of the extract was confirmed in a more severe model of cell damage: exposure of keratinocytes to higher UVB doses (300 mJ/cm2), which induce a 50% cell death. In keratinocyte cultures supplemented with 10 microg/ml, cell viability was almost completely preserved and more efficiently than with (-)-epigallocatechin 3-gallate and green tea. The results of this study indicate the potential use of Rhatany extracts, standardized in neolignans, as topical antioxidants/radical scavengers against skin photodamage.

Antimicrobial activity of bark extracts of Syzygium jambos (L.) Alston (Myrtaceae)

Syzygium jambos (L.) Alston (Myrtaceae) is a widespread medicinal plant traditionally used in sub-Saharan Africa to treat infectious diseases. Acetone and aqueous extracts from the bark of S. jambos were tested for antimicrobial activity in vitro by the agar dilution method in petri dishes. Both extracts showed some activity against the tested micro-organisms. They proved to be particularly effective on Staphylococcus aureus, Yersinia enterocolitica and coagulase negative staphylococci among which Staphylococcus hominis, Staphylococcus cohnii and Staphylococcus warneri. These properties seem to be related to the high tannin content of S. jambos extracts (77 and 83% for the aqueous and acetone extracts, respectively, determined according to the European Pharmacopoeia method) which were generally more active than Hamamelis virginiana, Krameria triandra, Alchemilla vulgaris and Rubus fruticosus extracts containing 48, 44, 46 and 28% tannins, respectively. Furthermore, elimination of tannins totally suppressed these antimicrobial activities.

In-vitro Antiherpetic Activity of <I>Erythroxylon laurifolium</I>(Erythroxylaceae)

Oligomeric and polymeric proanthocyanidins extracts from Erythroxylon laurifolium (Erythroxylaceae) and Krameria triandra (Krameriaceae), were found to have moderate activity against Herpes simplex virus type 1. No notable differences were found between the two types of compounds or plants. Proanthocyanidins did not affect viral attachment or penetration but did affect further events in the replicative cycle. An enzymatic inhibition was suggested. Direct inactivation of virus was found at high concentrations and may partially contribute to the antiviral effect of tannins.

Proanthocyanidins from Krameria triandra root.

Oligomeric proanthocyanidins were isolated from rhatany root (Krameria triandra) and characterised by acid hydrolysis, thiolytic degradation, and spectroscopic methods. They consisted of 2-14 flavanol units with mainly 2,3-cis configuration and with a propelagonidin:procyanidin ratio of 65:35. The predominant interflavan linkage was [4,8]. [4,6]-Bonds were present in the higher oligomers, presumably forming branched chain units. The astringency of the drug was mainly due to proanthocyanidins with degrees of polymerization from 5-10, and these were also the astringent compounds of rhatany tea and tincture. A pharmacological screening of the extract revealed a significant antimicrobial effect.