Phytochemical Screening of Echium angustifolium and Anchusa aegyptiaca Extracts and their Cytotoxic, Antitoxic, and Antimicrobial Activities

Comparative evaluation of cytotoxic, antimicrobial and antioxidant activities of the crude extracts of three Plectranthus species grown in Saudi Arabia

Ultrashort cationic lipopeptides (USCLs) are promising antimicrobial agents that may be used to combat pathogens such as bacteria and fungi. USCLs consist of a few basic amino acid residues and at least one lipid moiety, usually a fatty acid chain. Generally, USCLs are potent antimicrobials but their major shortcoming is a relatively high cytotoxicity and hemolytic activity. Glycopeptide antibiotics (e.g. vancomycin) are essential in combating bacterial infections and are popular in medicinal practice. However, literature concerning the effect of glycosylation of peptides on their antimicrobial activity is rather scarce. For the first time, this study highlights the effect of USCLs glycosylation on in vitro biological activity. The aim of this study was to evaluate the impact of glycosylation of a series of USCLs on antimicrobial activity, cytotoxicity and hemolytic activity. Straight-chain fatty acids (C14, C16, C18) were attached to the N-terminal amino group of tripeptides—SRR-NH2, RSR-NH2 and RRS-NH2. Two groups of the lipopeptides were synthetized, the first with unmodified L-serine (USCLs) and the other with L-serine O-glycosylated by N-acetyl-β-d-glucosamine to produce new class of glycosylated ultrashort cationic lipopeptide (gUSCLs). Both USCLs and gUSCLs were tested against planktonic and biofilm cultures of ESKAPE strains (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) and Candida glabrata, and hemolytic activity on human erythrocytes and cytotoxicity against the HaCaT cell line was examined. Generally, USCLs and gUSCLs proved to be active against all the tested strains. The highest activity displayed was by lipopeptides containing the C18 fatty acid. Antimicrobial, hemolytic and cytotoxic activities were mainly correlated with amino acid sequence (position of serine/glycosylated serine) and hydrophobicity of molecule and were found to be highly strain-dependent. In general, glycosylation did not guarantee an increased antimicrobial activity or a decreased hemolytic and cytotoxic activities. However, in some cases, gUSCLs proved to be superior to their USCLs analogs. The most pronounced differences were found for peptides with C18 fatty acid and serine at the first and second position against both planktonic cells and biofilm of C. glabrata, as well as the second and third position against S. aureus. It is noteworthy that gUSCLs were also more active against biofilm than were USCLs.

While oral rinses used for cosmetic purposes only do not necessarily have to be antiseptic, antimicrobial activity is required for medical indications, including oral and periodontal surgery. So the question arises—is the antimicrobial activity of oral rinses associated with any destructive changes in cell viability in vitro? To answer this question, we examined twelve oral rinses with respect to their antimicrobial and cytotoxic activity. Antimicrobial activity was screened against five bacterial strains using disc diffusion. Cytotoxicity was determined by mitochondrial reductase activity with primary gingival fibroblasts, L929 cells, and HSC-2 epithelial cells. Phase contrast microscopy and trypan blue staining were then performed to reveal cell morphology. Cells remained vital after exposure to oral rinses that were only used for cosmetic purposes. Moderate cytotoxic effects were observed for oral rinses containing 0.05% chlorhexidine, ethanol, or pegylated hydrogenated castor oil and sodium dodecyl sulfate. Other oral rinses containing 0.2% chlorhexidine and cocamidopropyl betaine exhibited strong cytotoxic and antimicrobial activity. Strong cytotoxic but moderate antimicrobial activity was observed in oral rinses containing cetylpyridinium chloride. The in vitro data show that oral rinses are heterogeneous with respect to their cytotoxic and antimicrobial effects. Based on their respective properties, oral rinses can be selected either to reduce the microbial load or for cosmetic purposes.

Antimicrobial, Antineoplastic and Cytotoxic Activities of Indole Alkaloids from Tabernaemontana divaricata (L.) R.Br.

In vitro evaluation of the total phenolic and flavonoid contents and the antimicrobial and cytotoxicity activities of crude fruit extracts with different polarities from Ficus sycomorus

BackgroundCancers and microbial infections are still a major health problem, therefore research on new anticancer and antimicrobial agents ought to be continued. Natural products including essential oils from medicinal plants continue to be an important resource to manage various diseases. Thus, the particular objectives of this study are to investigate the chemical composition, cytotoxic, antimicrobial and antioxidant activities of three Plectranthus species namely P. cylindraceus Hocst. ex Benth., P. asirensis JRI Wood and P. barbatus Andrews grown in Saudi Arabia.MethodsThe essential oils of the three Plectranthus species were obtained by hydrodistllation and analyzed using GC/FID and GC-MS. The essential oils were further assessed for their cytotoxic, antimicrobial and antioxidant activities. Determination of the cytotoxic activity was carried out against Hela, HepG2 and HT-29 cancer cell lines by utilizing MTT-assay. The antimicrobial activity was assessed against six bacterial and fungal strains by using broth micro-dilution assay. In addition, the antioxidant activity was evaluated utilizing the DPPH and β-Carotene-linoleic acid assays.ResultsThe GC/FID and GC-MS analysis led to the identification of 59, 60 and 42 compounds representing 89.0% 95.0 and 97.1% of the total essential oils of P. cylindraceus, P. asirensis and P. barbatus, respectively. The essential oils were characterized by a high content of oxygenated sesquiterpenes in P. cylindraceus, sesquiterpene hydrocarbons in P. asirensis and monoterpene hydrocarbons in P. barbatus where maaliol (42.8%), β-caryophyllene (13.3%) and α-pinene, (46.2%) were the predominant compounds. Additionally, the oils particularly of P. cylindraceus and P. barbatus exhibited remarkable cytotoxic and antimicrobial activities with IC50-values between 3.8 and 7.5 μg/mL and MIC-values ranging from 0.137 to 4.40 mg/mL. Moreover, the oils showed moderate to high radical scavenging and antioxidative activities ranging from 52 to 75% at the highest concentration of 1 mg/mL.ConclusionsThe observed results back the suggestion that these three Plectranthus species represent a promising source of cytotoxic and antimicrobial agents.

Objective: There is an increasing interest in the use of natural products to oppose human diseases. The leaves of Flacourtia rukam Zoll and A. Mortizi, Archontophoenix alexandrae (Wendl. and Drude), and Dictyosperma album (Bory) H. Wendl. and Drude ex. Scheff were selected for phytochemical and biological screening to search for new natural drugs. Total ethanolic extracts of the mentioned plants were subjected to preliminary phytochemical screening followed by screening their cytotoxic, antimalarial, antimicrobial, and anti-inflammatory activities. Materials and Methods: The extracts were tested for the presence of various phytochemicals. The cytotoxic activity was determined against five human cancer cell lines: melanoma, breast, oral, ovarian, and cervical cancers and two noncancerous cell lines. The antimalarial activity was determined against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum depending on the plasmodial lactate dehydrogenase activity. Antimicrobial screening was continued using the modified version of the CLSI method whereas anti-inflammatory activity was determined by measuring the activity of inducible nitric oxide synthase (iNOS). Results: Preliminary phytochemical screening indicated the absence of alkaloids, anthraquinones, and saponins in all the extracts. The latter showed no toxicity against the tested cancer cell lines and no activity against the tested microbes. The extract of D. album lacks the activity against D6 and showed a moderate activity against W2 P. falciparum (IC50= 41.7 μ/mL). D. album extract showed no inhibition for iNOS as contrary to F. rukam and A. alexandrae extracts which showed a good inhibition (IC50= 20 and 100 μ/mL, respectively). Conclusion: All tested extracts lack cytotoxic and antimicrobial activities.

The study focused to evaluate cytotoxic, antioxidant, antimicrobial and anticholinesterase activities of methanol extracts of Pleurotus ostreatus Jacq. (Pleurotaceae), Boletus edulis Bull. (Boletaceae), Tricholoma populinum J. (Tricholomataceae) Helvella queletii Bres. (Helvellaceae), Armillaria tabescens Emel. (Physalacriaceae), Psathyrella candolleana Fr. (Psathyrellaceae) and Helvella leucopus Pers. (Helvellaceae) mushroom species. Phenolic acid profiles of these mushrooms were also determined to obtain further information on the correlation between the contents of phenolic compounds and studied activities. Cytotoxic activity of mushrooms was screened by MTT cytotoxicity assay on cancer (HeLa) and normal epithelium (NRK-52E) cell lines. To determine antioxidant potential of mushroom extracts free radical scavenging, reducing power, superoxide anion radical scavenging, total antioxidant and metal chelating activities were studied, To indicate anthicholinesterase activity the acetyl-and butyrylcholinesterase inhibitory activities of the mushroom extracts were studied. For antimicrobial activity disc diffusion method was applied. Phenolic profile of mushrooms were determined by HPLC system. The IC50 values of the extracts were 1.58-25.11 and 2.05-22.32 mg/mL for HeLa and NRK-52E cells, respectively. At antimicrobial activity the inhibiton zones were found to be as 1 ± 0.12-13 ± 0.23 mm. P. ostreatus, B. edulis and H. leucopus extracts were showed higher activities than the other mushroms at antioxidant, antimicrobial, anticholinesterase and cytotoxic activity.

Antimicrobial and cytotoxic activities of isoniazid connected menthone derivatives and their investigation of clinical pathogens causing infectious disease

Açaí (Euterpe oleracea Mart.), a fruit from the Amazon, is valuable both economically and nutritionally. Its seeds, often discarded, can be transformed into bio-oil through pyrolysis (a thermochemical degradation process of residual biomass), providing a sustainable alternative to fossil fuels. This study investigates how temperature and molarity influence the antimicrobial, antioxidant, and cytotoxic activities of the produced bio-oil. Various assays were performed on bio-oil samples obtained under different pyrolysis conditions—specifically, at temperatures of 350, 400, and 450 °C, and molarities of 0.5 M, 1.0 M, and 2.0 M—to evaluate antimicrobial, antioxidant, and cytotoxic activities. Gas chromatography–mass spectrometry (GC–MS) was used to analyze the composition, revealing that phenolic compounds were the most abundant (55.70%), followed by cyclic and aromatic hydrocarbons (11.89%), and linear hydrocarbons (9.64%). Despite a reduction in oxygenated compounds, the bio-oil maintained bacteriostatic activity against Escherichia coli and Staphylococcus aureus, especially at 350 °C. The antioxidant activity was highest at 350 °C and at lower molarities. Additionally, lower concentrations of acid impregnation showed cytotoxic effects at higher temperatures. Thus, bio-oil from açaí seeds produced via pyrolysis demonstrates potential for antioxidant and antimicrobial activities, suggesting viability for further testing at dilutions with lower cytotoxicity.

A series of new tetracyclic oxathiine-fused quinone-thioglycoside conjugates based on biologically active 1,4-naphthoquinones and 1-mercapto derivatives of per-O-acetyl d-glucose, d-galactose, d-xylose, and l-arabinose have been synthesized, characterized, and evaluated for their cytotoxic and antimicrobial activities. Six tetracyclic conjugates bearing a hydroxyl group in naphthoquinone core showed high cytotoxic activity with EC50 values in the range of 0.3 to 0.9 μM for various types of cancer and normal cells and no hemolytic activity up to 25 μM. The antimicrobial activity of conjugates was screened against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus), Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), and fungus Candida albicans by the agar diffusion method. The most effective juglone conjugates with d-xylose or l-arabinose moiety and hydroxyl group at C-7 position of naphthoquinone core at concentration 10 µg/well showed antimicrobial activity comparable with antibiotics vancomicin and gentamicin against Gram-positive bacteria strains. In liquid media, juglone-arabinosidic tetracycles showed highest activity with MIC 6.25 µM. Thus, a positive effect of heterocyclization with mercaptosugars on cytotoxic and antimicrobial activity for group of 1,4-naphthoquinones was shown.

The plants of the genus Salvia synthesize several types of secondary metabolites with antimicrobial, cytotoxic, and radical scavenging activities and are used in the folk medicine of different countries. Eleven Salvia species including S. aegyptiaca, S. aethiopis, S. atropatana, S. eremophila, S. hypoleuca, S. limbata, S. nemorosa, S. santolinifolia, S. sclarea, S. syriaca, and S. xanthocheila were collected from different localities in Iran and screened for their cytotoxic activity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The antioxidant potential and total phenol contents of the plant extracts were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and Folin- Ciocalteu reagent respectively and finally antimicrobial activity of the above extracts were determined by using agar disc diffusion (ADD) and nutrient broth micro-dilution (NBMD) bioassays. Cytotoxic activity of methanol, 80% methanol and dichloromethane extracts of these plants were assessed on 3 human cancer cell lines. All of the extracts of S. eremophila and S. santolinifolia were active at IC50 values of 10.5-75.2 μg extract/mL, while the methanol and dichloromethane extracts of S. limbata, S. hypoleuca and S. aethiopis showed considerable cytotoxic activity against the tested cell lines. Among the tested plants for their antioxidant activity, S. nemorosa, S. atropatana, S. santolinifolia, and S. eremophila were the most active radical scavengers with higher total phenol contents while, S. limbata, S. xanthocheila and S. aegyptiaca were the weakest ones. The methanol extracts of S. santolinifolia, S. eremophila, S. sclarea and S. limbata inhibited the growth of all tested bacterial strains.

Propolis is a resinous natural mixtures collected and produced by honey bees. It is rich in essential oils and phenolic components so it has high levels of antioxidant, antimicrobial, anti-inflammatory and anti-tumoral activity. In this study the biochemical activity of propolis extracts were determined. The antimicrobial activity and cytotoxic activity of the extracts of the nine different propolis samples were invastigated. Their antimicrobial activities were tested by microdillution metod and define as minimum inhibitory concentration (MIC). Chemical composition of extracts was determined by using GC-MS equipment. Total phenolic content and antioxidant activity of the extracts was measured. Antimicrobial and cytotoxic activity of the extracts was carried out as well. All of the extracts showed antimicrobial activity on bacteria and yeasts used. Extracts had generally lower MIC values on yeasts. Therefore, yeasts were detected as more susceptible against the propolis extracts than the bacteria. Cytotoxic activity of extract were determined aganist A549 and Beas2B cell lines and IC50 values were calculated. Ma-Arapgir had the highest cytotoxic activity on A549 and Beas2B. They were determined as 6.72 and 26.44 mg/mL, respectively. It could be concluded that propolis extracts have antimicrobial and cytotoxic activity thus, propolis could be used in the treatment of cancer.

Hancornia speciosa Gomes (Apocynaceae) is a fruit tree, popularly known as mangabeira, and it is widely distributed throughout Brazil. Several parts of the plant are used in folk medicine, and the leaf and bark extracts have anti-inflammatory, antihypertensive, antidiabetic, and antimicrobial properties. In this study, we investigated the chemical composition of the ethanolic extract of Hancornia speciosa leaves (EEHS) and its antioxidant, antimicrobial, and cytotoxic activities as well as the mechanisms involved in cell death. The chemical compounds were identified by liquid chromatography coupled to mass spectrometry (LC-MS/MS). The antioxidant activity of the EEHS was investigated using the method that involves the scavenging of 2,2-diphenyl-1-picrylhydrazyl free radicals as well as the inhibition of oxidative hemolysis and lipid peroxidation induced by 2,2’-azobis (2-amidinopropane) in human erythrocytes. The antimicrobial activity was determined by calculating the minimum inhibitory concentration, minimum bactericidal concentration, minimum fungicidal concentration, and zone of inhibition. Kasumi-1 leukemic cells were used to assess the cytotoxic activity and mechanisms involved in cell death promoted by the EEHS. The chemical compounds identified were quinic acid, chlorogenic acid, catechin, rutin, isoquercitrin, kaempferol-rutinoside, and catechin-pentoside. The EEHS demonstrated antioxidant activity via the sequestration of free radicals, inhibition of hemolysis, and inhibition of lipid peroxidation in human erythrocytes incubated with an oxidizing agent. The antimicrobial activity was observed against American Type Culture Collection (ATCC) and hospital strains of bacteria and fungi, filamentous fungi and dermatophytes. The cytotoxic activity of the EEHS was induced by apoptosis, reduction of the mitochondrial membrane potential, and activation of cathepsins. Together, these results indicate the presence of phenolic compounds and flavonoids in the EEHS and that their antioxidant, antimicrobial, and cytotoxic activities in acute myeloid leukemia cells are mediated by apoptosis.

The crude methanolic extract of Dillenia indica Linn. (Dilleniaceae) leaves has been investigated for the evaluation of antimicrobial and cytotoxic activities. Organic solvent (n-hexane, carbon tetrachloride and chloroform) fractions of methanolic extract and methanolic fraction (aqueous) were screened for their antimicrobial activity by disc diffusion method. Besides, the fractions were screened for cytotoxic activity using brine shrimp (Artemia salina) lethality bioassay. Among the four fractions tested, n-hexane, carbon tetrachloride, and chloroform fractions showed moderate antibacterial and antifungal activity compared to standard antibiotic, kanamycin. The average zone of inhibition was ranged from 6 to 8 mm at a concentration of 400 µg/disc. But the aqueous fraction was found to be insensitive to microbial growth. Compared to vincristine sulfate (with LC50 of 0.52 µg/ ml), n-hexane and chloroform fractions demonstrated a significant cytotoxic activity (having LC50 of 1.94 µg/ml and 2.13 µg/ml, respectively). The LC50 values of the carbon tetrachloride and aqueous fraction were 4.46 µg/ml and 5.13 µg/ ml, respectively. The study confirms the moderate antimicrobial and potent cytotoxic activities of Dillenia indica leaves extract and therefore demands the isolation of active principles and thorough bioassay.