Cotinus coggygria Scop.: An overview of its chemical constituents, pharmacological and toxicological potential

Effects of natural waste on in vitro oxidative DNA damage

In this study, the effects of natural waste products such as extracts from C. coggygria leaves and Punica granatum L. peels were investigated against oxidative DNA damage induced by Fenton reaction. 8-OH-2'dG as a general marker of DNA damage on thymus DNA, and the bioactive compounds of extracts were measured by LC-MS/MS. Our results had shown that ethanol extracts of C. coggygria leaf and Punica granatum L. peel had a protective effect on oxidative damaged DNA. It was determined that the bioactive compounds of C. coggygria leaves (gallic acid, protocatechuic acid, myricetin, syringic acid and ethyl gallate as a major compounds) and Punica granatum L. peel (ellagic acid, abscisic acid, ethyl gallate, phlorizin, gallic acid, myricetin as major compounds) may have an important role in the protective effect against oxidative DNA damage. Therefore, Cotinus coggygria leaves and Punica granatum L. peel may have potential use in medicine or cosmetic fields.

The effects of peppermint (Mentha piperita L.) and chicory (Cichorium intybus L.) in comparison with a prebiotic on productive performance, blood constituents, immunity and intestinal microflora in broiler chickens

A total of 320 one-day-old broiler chickens were used in a 42-day feeding trial to evaluate the effects of peppermint (Mentha piperita L.) and chicory (Cichorium intybus L.) in comparison with a prebiotic on-growth performance, blood constitutes, immunity and intestinal microflora. The dietary treatments were as follows: basal diet (control); control + prebiotic (Fermacto™); control + 0.1% peppermint; control + 0.1% chicory, respectively. A significant (p < 0.05) body weight gain and feed intake was found at 21 and 42 days of growth period in broilers fed diet supplemented with 0.1% chicory compared with other groups. Feeding of prebiotic or chicory led to higher (p < 0.05) feed intake. Chickens fed control diet had higher (p < 0.05) abdominal fat compared with the other groups. Serum blood constituents indicated that broilers fed prebiotic or supplemented with peppermint or chicory had reduced (p < 0.05) levels of cholesterol, triglycerides and low-density lipoprotein than control group. Immunity-related parameters showed that chicken fed chicory had lower (p < 0.05) heterophil-to-lymphocyte ratio compared with the other groups. Intestinal microflora revealed that chickens fed prebiotic or herbals had higher count of Lactobacillus and lower E. coli than control. Thus, it can be concluded that broiler dietary supplementation with prebiotic or chicory can improve performance supporting positively health status.

Cytotoxic effect of Cotinus coggygria extract on Hep3B cancer cell line

Cotinus coggygria Scop. is a medicinal plant which contains a variety of precious phytochemical compounds applicable in traditional medicine. The aim of this study is to investigate the cytotoxic effect of Cotinus coggygria extract on Hep3B cancer cells. The cytotoxic effect was measured by MTT assay. Based on IC50 values, the C. coggygria leaf extract showed cytotoxic effect on Hep3B cancer cells, which was found better at 24 h (IC50 = 3.642) then at 48 h (IC50 = 3.956). Also, the dose of C. coggygria extract showed negative correlation (p < 0.05) with cell viability of 24 h and 48 h and positive correlation (p < 0.05) with cytotoxic effect of 24 h and 48 h. The cytotoxic effects were concentration-time dependent. According to our study, C. coggygria extract had protective effect at 24 h on AML12 cell line and cytotoxic effect on the Hep3B cancer cell line, where it indicates that it may have an antitumorigenic effect.

Cotinus coggygria Scop. Attenuates Acetic Acid-Induced Colitis in Rats by Regulation of Inflammatory Mediators

In traditional medicine, many medicinal plants are used in the treatment of various diseases caused by inflammation. The objective of the present study is to elucidate for the first time the effects of Cotinus coggygria (CC) ethanol extract (CCE) on colonic structure and inflammation of acetic acid-induced ulcerative colitis in rats. Colonic damage was assessed using disease activity index score, enzyme-linked immunosorbent assay, and hematoxylin-eosin staining. Also, in vitro antioxidant activity of CCE was investigated by ABTS methods. Total phytochemical content of CCE was measured spectroscopically. Acetic acid caused colonic damage according to disease activity index and macroscopic scoring. CCE significantly reversed these damages. While the levels of proinflammatory cytokines TNF-alpha, IL-1beta, IL-6, and TGF-1beta increased in tissue with UC, IL-10 level decreased. CCE increased inflammatory cytokine levels to values close to the sham group. At the same time, while markers indicating disease severity such as VEGF, COX-2, PGE2, and 8-OHdG indicated the disease in the colitis group, these values returned to normal with CCE. Histological research results support biochemical analysis. CCE exhibited significant antioxidant against ABTS radical. Also, CCE was found to have a high content of total polyphenolic compounds. These findings provide evidence that CCE might be benefit as a promising novel therapy in the treatment of UC in humans due to high polyphenol content and justify the use of CC in folkloric medicine for treatment of inflamed diseases.

Isolation and characterization of natural inhibitors of post-proline specific peptidases from the leaves of Cotinus coggygria Scop

ETHNOPHARMACOLOGICAL RELEVANCE

Cotinus coggygria has a number of applications in traditional medicine most of which are connected with its anti-inflammatory and anti-oxidant properties. Since inflammation and oxidative stress are recognized as triggering factors for cancer, anti-cancer activity has also been documented and the possible mechanisms of this activity are under investigation. Important components of C. coggygria extracts are shown to be hydrolysable gallotannins of which pentagalloyl-O-glucose has been studied in details. This compound inhibits various enzymes including prolyl oligopeptidase which is involved in tumorigenesis and tumour growth. According to our pilot studies, oligo-O-galloylglucoses with more than five galloyl residues are also presented in the herb of Bulgarian origin, but their activities have not been examined.

AIM OF THE STUDY

To establish an extraction method by which it is possible to concentrate high molecular hydrolysable gallotannins from dried leaves of Cotinus coggygria and to determine their inhibitory properties towards prolyl oligopeptidase and fibroblast activation protein α.

MATERIALS AND METHODS

Dried leaves of C. coggygria were extracted using different solvents in single-phase or biphasic systems under various extraction conditions. Main compounds of the extracts were identified by using high performance liquid chromatography and liquid chromatography - high resolution mass spectrometry. The extracts' inhibitory properties towards prolyl oligopeptidase and fibroblast activation protein α were studied on recombinant human enzymes by enzyme kinetic analyses using a fluorogenic substrate.

RESULTS

Ethyl acetate/water (pH 3.0) extraction of dried plant leaves proved to be the most efficient method for isolation of high molecular hydrolysable gallotannins which can be further concentrated by precipitation of dicyclohexylammonium salts in ethyl acetate. The main components of those extracts were oligo-O-galloyl glucoses with more than five gallic acid residues. They were shown to inhibit both enzymes studied but were about 30 times more effective inhibitors of prolyl oligopeptidase.

CONCLUSIONS

C. coggygria from Bulgarian origin is shown to possess a substantial quantity of oligo-O-galloyl glucoses with more than five gallic acid residues which has not been described thus far in the same herb from other sources. An extraction method useable for concentrating those compounds is established. They are found to inhibit prolyl oligopeptidase with a very good selectivity to fibroblast activation protein α. The previously described antitumor activity of this plant may be at least in part due to the inhibition of the above enzymes which has been shown to participate in the genesis and development of various types of tumors.

The Impact of Acute Low-Dose Gamma Irradiation on Biomass Accumulation and Secondary Metabolites Production in Cotinus coggygria Scop. and Fragaria × ananassa Duch. Red Callus Cultures

Cotinus coggygria Scop. (smoketree) and Fragaria × ananassa Duch. (strawberry) are two industrially important species due to their composition in bioactive compounds. In this study, we investigated the effects of acute low-dose gamma irradiation (15, 20, 25, 30, 35 and 40 Gy) on two red callus cultures established in smoketree and strawberry. The biomass production, dry weight, content of phenols, flavonoids, monomeric anthocyanins', index of anthocyanins polymerization and antioxidant activity were evaluated. For the smoketree callus, a negative correlation between irradiation doses and callus biomass accumulation was observed. For the strawberry callus, irradiation did not significantly affect the accumulation of the biomass. An increased dry weight was observed in irradiated smoketree callus, while for treated strawberry callus, a decrease was recorded. Irradiation with 30 Gy was stimulative for polyphenols' accumulation in both cultures; however, the increase was significant only in the strawberry callus. The flavonoids increased in the 30 Gy strawberry variants, while it significantly decreased in smoketree callus irradiated with 35 and 40 Gy. In irradiated strawberry callus, except for the 25 Gy variant (1.65 ± 0.4 mg C-3-GE/g DW), all treatments caused an increase in anthocyanins' accumulation. In smoketree, except for the 15 Gy variant (2.14 ± 0.66 mg C-3-GE/g DW), the irradiation determined an increase in anthocyanins synthesis, with the highest value being seen in the 20 Gy variant (2.8 ± 0.94 mg C-3-GE/g DW). According to UPLC-HRMS investigations, an unidentified compound increased by 99% at the 30 Gy dose in strawberry callus, while in smoketree, maslinic acid increased by 51% after irradiation with 40 Gy. The results of this study showed, for the first time, the differential response of two performant callus cultures to low-dose gamma irradiation, a biotechnological method that can be used to stimulate the synthesis of important flavonoids and triterpenes.

Screening of trypsin inhibitors in Cotinus coggygria Scop. extract using at-line nanofractionation coupled with semi-preparative reverse-phase liquid chromatography

In this study, an at-line nanofractionation (ANF) platform was successfully fabricated in parallel with mass spectrometry and trypsin inhibitory bioactivity assessment for rapid screening of trypsin inhibitors (TIs) from natural products for the first time. After systematic optimization, the ANF platform was applied to screen and identify TIs in the extract of a traditional Chinese herb, i.e., Cotinus coggygria Scop. The semi-preparative reverse-phase liquid chromatography was used subsequently to further simplify and enrich the insufficiently separated components. After comprehensive evaluation and validation, the ANF platform successfully identified 12 compounds as potential TIs, including 8 flavonoids and 2 organic acids. Additionally, a comparison study was conducted using two other ligand fishing approaches, i.e., capillary monolithic and magnetic beads-based trypsin-immobilized enzyme microreactors, which successfully identified 8 identical flavonoids as TIs. Importantly, the molecular docking study showed the molecular interactions between enzymes and inhibitors, thus strongly supporting the experimental results. Overall, this work has fully demonstrated the feasibility of the established ANF platform for screening TIs from Cotinus coggygria Scop., and proved its great prospects for screening bioactive components from natural products.

Evaluation of Factors Affecting Tree and Shrub Bark's Antioxidant Status

The importance of using the barks of trees and shrubs as powerful natural antioxidants suggests the necessity to evaluate the effect of different environmental factors on bark extracts’ quality. The determination of total antioxidant activity (AOA) and polyphenol content (TP) in the bark of 58 tree and shrub species from 7 regions differing in mean annual temperature, insolation, humidity, salinity level, and altitude was performed. The above stress factors positively affected bark AOA but did not have a statistically significant effect on TP. The bark of trees grown in the seashore proximity was characterized by significantly higher AOA than samples gathered in other areas, similarly to the trees grown at high altitude. The bark antioxidant status of 18 species was described for the first time. New sources of powerful antioxidants were represented by the ornamental shrubs Cornus sanguinea and Cornus alba, which showed the highest AOA (169−171 mg GAE g−1 d.w.). Among the typical halophytes, Calligonum and Tamarix had high AOA (172 and 85 mg GAE g−1 d.w.), while in the bark of tamarisk, an Se accumulator, an Se concentration of about 900 µg kg−1 d.w. was recorded. A significant positive correlation was found between leaves and bark AOA in the Karadag Nature Reserve’s deciduous trees (r = 0.898, p < 0.01). The relationship between bark AOA and TP was highly significant (r = 0.809; p < 0.001) for all samples except the mountainous ones. The results of the present research revealed new opportunities in successive bark utilization.

Assessment and abatement of the eco-risk caused by mine spoils in the dry subtropical climate

The highly rugged mountainous land topography of the Novorossiysk industrial agglomeration (NW Caucasus, Krasnodar Krai, Russia) and arid climate limit the restoration abilities of disturbed mine lands. Abandoned waste-rock dumps of a marl quarry occupy an area of ca. 150,000 m² next to the cement plant, residential districts, and a commercial seaport. To assess the eco-risk, topsoil horizons of urban and mine-site Technosols and background Rendzinas were sampled and analyzed; measurements of particulate matter fractions PM1, PM2.5, PM4, and PM10 were conducted throughout the agglomeration. Fugitive dust emission from the unreclaimed marl dumps raises the PM2.5 content in the air by a factor of 2.68 on average. The high sorption capacity of the fine eluvium results in the accumulation of urban emissions by the dust and contributes to the subsequent soil pollution; the Cumulative Pollution Index of pedochemical anomalies reaches the high-risk level over the areas of up to 5 km². Environmental threats caused by the mine dumps can be assessed more reliably by means of land zoning based on accumulated environmental damage indicators and the debris flow and waterspout risk calculation. To abate the technogenic impact caused by the mine spoils, reclamation actions must be taken including soil stabilization on sensitive sites by application of geosynthetic cover, hydroseeding of the mixture of soil improvers and seeds of herbaceous plants on the slopes, and anti-erosion plantation of cades (Juniperus oxycedrus L.) and smoke trees (Cotinus coggygria Scop.) at subhorizontal surfaces.

Flavonoids of the Heartwood of Cotinus coggygria Scop. Showing Protective Effect on Human Lymphocyte DNA

In continuation of our study on Cotinus coggygria from Serbia, 10 known flavonoids (1-10) were isolated from the methylene chloride/methanol extract of the heartwood. They were tested for in vitro protective effect against chromosome aberrations in peripheral human lymphocytes, using the cytokinesis-block micronucleus assay. All tested compounds (in minimal doses of 1 μg/mL) exerted a beneficial effect by decreasing DNA damage of human lymphocytes in the range of 24.2% to 54.5%, better than the radio protectant control, amifostine. Functional groups, such as 3′,4′-dihydroxyphenyl (catechol), 5-OH, 3-OH, and 4-keto in flavonoids (3-keto in aurones), which play a key role in antioxidant activity, are proposed to be responsible for the DNA protective activity of the tested compounds.

Chemical Composition and Content of Biologically Active Substances Found in Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha Growing in Various Territories

Medicinal plants (Cotinus coggygria, Dactylorhiza maculata, Platanthera chlorantha) growing in various territories (Kaliningrad, Moscow, and Minsk regions) were the objects of research. This paper presents a study of the chemical composition of these plants. To analyze the qualitative and quantitative composition of biologically active substances, the method of high-performance liquid chromatography was used. Atomic absorption spectrometry was used to study the content of trace elements. The content of organic acids and vitamins was determined by capillary electrophoresis using the Kapel-105/105M capillary electrophoresis system with high negative polarity. Extracts of medicinal plants were obtained on a Soxhlet apparatus using 70% ethanol as an extractant. It was found that among the biologically active substances in the plants under discussion, hyperoside, rutin (C. coggygria), Ferulic acid and Gallic acid (D. maculata), triene hydrocarbon (3,7-Dimethyl-1,3,6-octatriene), unsaturated alcohol (3,7-Dimethyl-2,6-octadien-1-ol), and benzyl acetate (P. chlorantha) prevailed. Samples of these medicinal plants contained trace elements (phosphorus, potassium, calcium, sodium, magnesium, and sulfur) and many aliphatic organic acids (succinic acid, benzoic acid, fumaric acid, citric acid, oxalic acid, and tartaric acid). The largest amount of biologically active substances and secondary metabolites of the studied plants from the Eastern Baltic is associated with climatic and ecological differences from other regions. The composition of these plants determines the potential of their use in feed additives for livestock and poultry as part of measures to improve the quality of livestock products. The use of medicinal plants for the production of feed additives is relevant in terms of improving regional economies, as well as improving the quality of life and nation’s health by providing ecologically clean livestock products.

Efficacy of Different Concentrations of NAA on Selected Ornamental Woody Shrubs Cuttings

Ornamental woody shrubs are used in landscape design worldwide. Their propagation can be made generatively and vegetatively. Vegetative propagation methods are mostly used by nurseries, as such methods are quick and the newly propagated plants inherit the genetics of the mother plant. However, rooting in some woody plants is slow and, unfortunately, sometimes produces only a small number of rooted cuttings. In this study, shoot cuttings from six selected ornamental woody shrubs were subjected to different concentrations of rooting stimulators (0.5 (NAA5) and 0.8 (NAA8) % concentrations of 1-Naphthylacetic acid; cuttings without treatment were considered as control) and propagated in two different periods (spring and summer). Our results show that significant changes were obtained in the plants under the different treatments. Most of the plants showed a positive response to both treatments, expect for Cotinus coggygria ‘Royal Purple’, which, compared to control, registered decreases in all the tested parameters under NAA5 treatment. Ilex aquifolium was the species that showed increments in all the parameters when NAA treatments were applied. In conclusion, our research suggests that NAA increases rooting in ornamental woody shrubs, although in some cases rooting could be a species-dependent process.

The complete plastid genome of Cotinus coggygria and phylogenetic analysis of the Anacardiaceae

Cotinus coggygria Scop. (Anacardiaceae) is an important ornamental tree with beautiful characteristics that is grown in China. In this study, the complete plastid genome of C. coggygria was sequenced and assembled. This genome was 158,843 bp in size and presented a typical tetrad structure, consisting of a large single-copy region (87,121 bp), a pair of inverted repeat regions (26,829 bp), and a small single-copy region (18,064 bp). A total of 134 genes were annotated, including 88 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. We observed a deletion that caused the loss of the rpl32 gene, and a small expansion of IR regions resulted in the trnH gene accessing IR regions; two copies were obtained. Phylogenetic analysis showed that C. coggygria was most closely related to Pistacia, with 100% bootstrap support within Anacardiaceae. In this study, we report the plastid genome of Cotinus species for the first time, which provides insight into the evolution of the plastid genome in Anacardiaceae and promotes the understanding of Cotinus plants.

Study of the Biologically Active Properties of Medicinal Plant Cotinus coggygria

The results of the studies have shown that to obtain an extract of a complex of biologically active substances of Cotinus coggygria, ethyl alcohol (mass fraction of alcohol 70%) with a hydromodule of 1:5 should be used, and the extraction should be carried out for 60 min at a temperature of 60 °C. The investigated plant extracts with the complex of bioactive substances from the Cotinus coggygria leaves and flowers are safe from the point of view of the content of heavy metals, pesticides, aflatoxin B1, radionuclides, as well as pathogenic and opportunistic microorganisms. It has been established that the Cotinus coggygria extract contains rutin, hyperoside, ferulic acid, quercetin, kaempferol, disulphuretin, sulphurein, sulphurein, gallic acid, methyl gallate, pentagalloyl glucose, 3,3',4',5,6,7-hexahydroxyflavonone, 3,3',4',5,5',7-hexahydroxyflavonone, 3-O-α-L-rhamnofuranoside, 3,3',4',5,5',7-hexahydroxyflavulium(1+), 7-O-β-D glucopyranoside, and 3,3',4',7-tetrahydroxyflavonone. The tested extracts have anticancer, antigenotoxic, and antimicrobial (against E. coli, S. aureus, P. vulgaris, C. albicans, L. mesenteroides) properties. The high antioxidant status of the tested extracts was established; the antioxidant activity of the samples was 145.09 mg AA/g (AA-ascorbic acid).

Integrating Ethnobotany, Phytochemistry, and Pharmacology of Cotinus coggygria and Toxicodendron vernicifluum: What Predictions can be Made for the European Smoketree?

The smoketree (Cotinus coggygria) is a historically known medicinal plant from Southeast Europe. Its ethnomedicinal use in skin and mucosal lesions is commonly accepted across countries. Other utilizations reported locally include fever reduction, cardiac diseases, hypertension, urinary diseases, cough, asthma, hemorrhoids, diabetes, numbness of arm, liver disease, and cancer. Departing from the smoketree's traditional uses, this review summarizes investigations on the phytochemistry and bioactivity of the plant. In vitro and in vivo experiments supporting wound-healing, anti-inflammatory, antibacterial, cytotoxic, antioxidative, hepatoprotective, and antidiabetic effects are presented. Metabolites from smoketree that are responsible for the main pharmacological effects of smoketree are pointed out. Furthermore, the review performs a comparison between C. coggygria and the lacquer tree (Toxicodendron vernicifluum). The latter is a comprehensively studied species used in Asian phytotherapy, with whom the European smoketree shares a consistent pool of secondary metabolites. The comparative approach aims to open new perspectives in the research of smoketree and anticipates an optimized use of C. coggygria in therapy. It also points out the relevance of a chemosystematic approach in the field of medicinal plants research.

Chemical Composition and Antifungal Activity of the Essential Oil of Cotinus coggygria from Marche Region (Italy)

The present study reports the results of gas chromatography-mass spectrometry (GC/MS) analyses of the essential oil from flowering aerial parts of Cotinus coggygria Scoop. (Anacardiaceae), as well as its in vitro antifungal activity against nine plant pathogenic fungi. Moreover, the essential oil was evaluated for its antifungal activity using the agar dilution method, and also MICs (minimum inhibitory concentrations) and MFCs (minimum fungicidal concentrations) were determined. The major compounds identified by GC-MS were limonene (49.2%), (Z)-β-ocimene (13.6%), α-pinene (8.8%) and (E)-β-ocimene (5.9%). The oil showed in vitro antifungal activity against some species of the Fusarium genus, Botrytis cinerea, and Alternaria solani. Our study indicates that the oil of C. coggygria could be used as a control agent for plant pathogenic fungi in natural formulations.

Ethanol extract of Cotinus coggygria leaves accelerates wound healing process in diabetic rats

CONTEXT

Cotinus coggygria Scop. (Anacardiaceae) leaves that were used as wound healing in traditional Balkan and Anatolian folk medicine, could be potentially effective in treating diabetic wounds.

OBJECTIVE

This study investigates biochemical and histological effects of ethanol extract of C. coggygria (CCE) on excision wound model in diabetic rats.

MATERIALS AND METHODS

This study was conducted on diabetic Wistar albino rats, which were injected by a single dose (50 mg/kg i.p.) streptozotocin. Afterward an excision wound model was created in all animals; diabetic control rats were applied topically simple ointment and diabetic treatment rats were applied topically 5% (w/w) ointment with CC, once a day during the experimental period. Malondialdehyde, glutathione and hydroxyproline levels in wound tissues were investigated at the end of 3rd, 7th, and 14th days. Histopathological examination was also performed.

RESULTS

Hydroxyproline content was significantly increased in the CCE treated group versus control after the 3rd and 7th days (15.33 versus 11.83; 19.67 versus 15.67 mg/g, p < 0.05; respectively). A statistically significant elevation in glutathione at the end of 3rd, 7th, and 14th days (5.13 versus 1.58, p < 0.05; 4.72 versus 1.88, p < 0.05; 3.83 versus 1.88 μmol/g, p < 0.05, respectively) and a statistically significant decrease in malondialdehyde level at the end of 7th day (4.49 versus 1.48 nmol/g, p < 0.05) were determined in the treated group versus control group. These results were also supported by histological analyses.

DISCUSSION AND CONCLUSION

These findings indicate that CCE accelerated the cutaneous wound healing process in diabetic wounds, in confirmation of its traditional use.

The Activity of Cotinus coggygria Scop. Leaves on Staphylococcus aureus Strains in Planktonic and Biofilm Growth Forms

The purpose of this study was to detect the effectiveness of Cotinus coggygria Scop. leaves methanol extract against planktonic and biofilm growth forms of Staphylococcus aureus. The antimicrobial activity was determined by the broth microdilution test. Minimal inhibitory concentrations and minimal bactericidal concentrations were detected against two collection and ten clinical S. aureus strains. Anti-biofilm activity of the tested extract was detected using 24 h bacterial biofilm on the surface of microtiter plate wells. The biofilm inhibitory activity was evaluated visually after 24 h interaction of extract with biofilm, and the eradicating activity by a regrowth method. The tested extract showed bactericidal activity against all S. aureus strains (methicillin susceptible or methicillin resistant) in concentrations ranging from 0.313 to 0.625 mg·mL⁻¹. Biofilm inhibitory concentrations were 10-times higher and biofilm eradicating concentrations 100-times higher (8 and 32 mg·mL⁻¹, respectively). The phytochemical analysis of C. coggygria leaves 60% methanol extract performed by LC-DAD-MS/MS revealed quercetin rhamnoside, methyl gallate, and methyl trigallate as main constituents. Results of our study indicate that C. coggygria, rich in tannins and flavonoids, seems to be a prospective topical antibacterial agent with anti-biofilm activity.