Interference of Antioxidant Flavonoids with MTT Tetrazolium Assay in a Cell Free System

Introduction: The tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) used extensively to measure the quantitative survival and proliferation of mammalian cells. The analysis is based upon the reduction of MTT by metabolically active cells to insoluble formazan crystals. Flavonoids are a large group of natural compounds found in plants with variable phenolic structures. Flavonoids, as they are potential reducing agents, they act as a free radical scavenger. The aim of the study is to assess the reducing effect of some of the flavonoids on tetrazolium salt and their interference with the colorimetric analysis of MTT. The cell viability obtained from the MTT assay was compared with that of SRB assay in the determination of flavonoids cytotoxicity. Materials and Methods: The present study examined the effect of few bio-flavonoids like Quercetin, EGCG, Rutin and Resveratrol to reduce MTT in the absence of cells under different experimental conditions such as concentration of flavonoids, incubation time and results were compared with SRB assay findings. The study also involves the analysis of flavonoid cytotoxicity on lung cancer cells NCIH-460 and NCIH-522 by MTT and SRB assay to establish the suitable cell viability assay for flavonoids. Results: All the flavonoids showed the instant formation of the dark blue formazan salt in the absence of the cells with MTT assay. Whereas SRB assay of flavonoids in the absence of cells, results showed the absorbance similar to that of the blank, indicating that SRB did not interfere with flavonoids in a cell-free system. Conclusion: From the results, it is evident that MTT is not a suitable method to determine the effect of flavonoids on cell viability and proliferation as flavonoids itself reduces the MTT to formazan crystals. Study also suggests that SRB assay is more suitable method to determine the effect of flavonoids on cell viability.

The Cytotoxic Effect of the Extract of Anchusa strigosa (Him Him) Grown in Jordan Against Different Cancer Cell Lines

Anchusa strigosa - prickly alkanet from Boraginaceae grows in roadsides, and fields of a broad range of habitats from mediterranean woodlands, to steppe vegetation, to true desert. It is commonly known as" him him" or "lisan al thawr". Anchusa can withstand hard weather conditions and hence is widely cultivated. The color of its flowers can range from pure white to deep cobalt blue. Various parts of A. strigosa are used in traditional medicine for treating several diseases or symptoms, such as abdominal pain, bronchitis, cough, and diarrhea. The goal of this study was to examine the cytotoxic effect of the crude extract of A. strigosa roots and leaves and their fractions against various tumor cell lines: adenocarcinoma MCF-7, human breast ductal carcinoma T-47D; human breast carcinoma MDA-MB-231; and colorectal carcinomas Caco-2. In conclusion the antiproliferative effect was assessed by SRB assay where it showed that the phytochemical constituents in the leaf part of the plant (A. strigosa) do have more potential in depressing the proliferation rate of the cell lines than the root part.

Halo-phenolic metabolites and their in vitro antioxidant and cytotoxic activities from the Red Sea alga Avrainvillea amadelpha

From the green alga Avrainvillea amadelpha, two new naturally halo-benzaldehyde derivatives were isolated by various chromatographic methods along with 10 known metabolites of bromophenols, sulfonoglycolipid, and steroids. Based on the 1D and 2D NMR spectra as well as on MS data, the structures of the new compounds were identified as 5-bromo-2-(3-bromo-4-hydroxybenzyl)-3,4-dihydroxybenzaldehyde named avrainvilleal (1), and 3-iodo-4-hydroxy-benzaldehyde (2). Using SRB assay, both compounds showed mild and weak cytotoxic activity against HeLa and MCF-7 cancer cell lines, compared to the good activity of their extract (IC50 values 3.1 and 4.3 μg/mL, respectively). However, avrainvilleal (1) displayed an effective scavenged DPPH radical activity with IC50 value 3.5 μM, compared to the antioxidant quercetin with IC50 value 1.5 μM.

Comparative Cytotoxicity of Selected Mikania species using Brine Shrimp Lethality Bioassay and Sulforhodamine B (SRB) Assay

This study aims to assess the comparative cytotoxic activity of the ethanolic extract of Mikania cordata (MC), Mikania micrantha (MM) and Mikania scandens (MS) (Family: Asteraceae) using brine shrimp lethality bioassay and colorimetric sulforhodamine B assay method. In SRB assay, A549 human lung carcinoma, SK-Mel-2 skin melanoma and B16F1 mouse melanoma cell lines were used. In brine shrimp assay, the LC50 for MC, MM, MS and vincristine were found to be 29.04, 15.84, 32.35, and 1.2 μg/ml, respectively. The results indicate that all the Mikania species showed moderate lethality against nauplii. In SRB assay, 50% cell growth inhibition concentration (IC50) of MC, MM, MS and cisplatin against B16-F1 were 33, 15, 39 and 6.8 μg/ml, respectively. Similar data were observed for other cell lines indicating moderate cytotoxicity of the extracts. Among the species, M. micrantha showed relatively potent cytotoxic effect followed by M. cordata and M. scandens. Similar data were observed for brine shrimp lethality bioassay and the results suggest that M. micrantha possesses highest cytotoxic potentials among all the species. Bangladesh Pharmaceutical Journal 24(1): 11-16, 2021

Phytochemical screening and In-vitro antibacterial and anticancer activity of crude extract of Matricaria aurea

Background: Infectious diseases constantly represent the source of sickness as well as mortality in human beings. Herbal applications in human life through using plants for antibacterial and anticancer activity have shown the potential medicinal outcome. Objectives: To evaluate the antibacterial and anticancer activities of the crude extract of Matricaria aurea. Materials and Methods: The antibacterial activity of the crude flowers of M. aurea extract was examined against reference and clinical bacterial strains by agar well diffusion method. Minimum inhibitory concentrations and minimum bactericidal concentrations were determined by micro broth dilution assays using MH broth. Herbal extract was employed over human breast adenocarcinoma cell line (MCF-7), hepatocellular carcinoma cell line (HepG-2) and colorectal adenocarcinoma cell line (HCT-116) to optimize cancer cells proliferation by SRB assay. Results: The data has shown that the extract from M. aurea had significant antimicrobial activity against the tested microorganisms. The plant extract showed higher antibacterial activity against the reference strain of Streptococcus pyogenes. The MIC and MBC varied between 0.38-12.5 mg/ml and 3.1-200 mg/ml respectively. Synergy study elucidated the significant bacteriostatic effect of M. aurea extract on S. aureus and S. saprophyticus. The data of SRB assay deliver the potential anticancer activity through cell death. Conclusion: This study delivers innovative information that M. aurea possessed excellent bio-activities against pathogenic microbes and cancer cells, which drive attention for further research to explore the active components responsible for biological efficacies.

In vitro bioassessment of novel δ- carboline derivatives as an antiproliferative agent

Several carboline derivatives are anticancer agents and studied for antiproliferative action against various cancer cells. Based on the preliminary analysis using insilico strategies, we have selected eight compounds for the study. All compounds have been synthesised and characterised for their purity and chemical composition. Antiproliferative activity was assessed by insilico Carcinogenicity assay, Cytotoxicity analysis by sulphorhodamine B, Antiproliferation assay and DNA damage analysis. The cytotoxic effects of the CH5, CH17, CH29, CH34, CH37, CH39, CH42 and CH47 on Vero, HeLa, A549, BRL3A, HCT116, and MCF7 were determined using the SRB assay. CH5, CH34, CH37 and CH42 was the most potent cytotoxic towards HCT116 cells with CTC50 value of 62.1±0.19, 47.1±0.41, 78.5±1.26 and 32.1±1.11 µg/ml respectively. The assay revealed a noticeable reduction in cell number for CH5 and CH37 tested except CH34 and CH42. CH5 and CH37 observed cytotoxic effects were found to destroy the cells according to time, and cell viability decreased with that time length. To learn their role in cell death, CH5 and CH37 were therefore taken up for a further screening. This study suggested that CH5 and CH37 had a separate mechanism of action to kill and that in the cell line. Such results will provide enrichment of scientific knowledge on the molecular mechanism and target therapies of CH5 and CH37, thereby potentially helpful for patients with Colon cancer.

Assessment of cytotoxic and antimicrobial activity of selected gingival haemostatic agents – in vitro study

Purpose: The present research aimed to determine whether and how the aluminium chloride – based materials affect the cell line of the bacterial line and fungi. Methods: Cytotoxicity of haemostatic astringents: Alustat (liquid), Alustat (gel), Alustat (foam), Alustin, Hemostat, Racestyptine and Traxodent containing AlCl3 was conducted on L929 cell line with the use of MTT and SRB assays. The antimicrobial activity (CFU and MIC) against C. albicans, S. mutans, L. rhamnosus was determined. Results: In the MTT results, cell viability for all agents were very low. In SRB, the lowest cytotoxicity was demonstrated for Hemostat and Alustat (foam), Traxodent and Racestyptine. Total reduction of the CFU of S. mutans was observed. Alustat (gel) and Alustat (liquid) completely inhibited the growth of C. albicans, S. mutans and L. rhamnosus. Conclusions: The viability of L929 cells obtained in the SRB assay is more reliable than that obtained in the MTT assay, in the case of gingival haemostatic agents.

Comparative Antiproliferative activity of aerial parts of few Apocynaceae plants in HepG2, HT29 and SK-OV3 Human cancer cell lines

Aims: Apocynaceae family is the 5th largest medicinal plant family rich in potent secondary metabolites such as Alkaloids, Cardiac glycosides,Terpenoids, irridoid/secoirridoids, flavonoids and Phenolic contents. The present study was aimed to evaluate and compare in-vitroantiproliferative activity of three plants of this family.Methods: Aerial parts of Carissa carandas Linn. (C), Nerium indicum Mill. (N) and Wrightia tinctoria RBr. (W), were collected and dried. Thepowdered drugs were extracted in Ethanol (1), 60% Ethanol (2) and Water (3). Estimation of Phytoconstituents performed using standardmethods. In-vitro cytotoxic activity performed using Sulphorhodamine B (SRB) assay in HepG2, HT29 and SKOV3 human cancer cell lines takingAdriamycin (ADR) as standard. For extracts, GI50 value ≤ 20μg/ml was considered to demonstrate activity.Results: For HepG2 cell line graphs and photomicrographs showed GI50 value as ADR=39.79, C1=2.5, N2=66.3, N3<10 and C2=C3= N1=W1-3>80. Also TGI for C1>80. The extracts, C1, C2, N1, N2, and N3 were found to possess activity against HepG2.These extracts were screened onHT 29 and SKOV3cell lines. The GI50 value observed was<10 for C1, N2, N3 and ADR in HT 29 and <10 for N3 and ADR in SK OV3 cell lines.Thus it was found that aqueous extract of Nerium indicum (N3) and Ethanolic extract of Carissa carandas (C1) were most cytotoxic extractsagainst all three cell lines.Conclusions: our study establishes that Apocynaceae family plants could be an important anticancer lead and could serve as Botanical drug forneoplasia.Keywords: Apocynaceae, SRB Assay, Phytoconstituents, Anticancer drug screening models, Hep G2, HT 29, SK-OV3, HCC.

Antarvedisides A-B from Manglicolous Lichen Dirinaria consimilis (Stirton) and their Pharmacological Profile

The chemical examination of acetone extract of Dirinaria consimilis resulted in isolation of six depsides of which two novel metabolites namely antarvediside A (1) and antarvediside B (2) and four known metabolites i.e. sekikaic acid (3), atranorin (4), divaricatic acid (5) and 2’-O-methyl divaricatic acid (6). From the pharmacological screening of the isolates (1-6), it was found that 1 and 2 exhibited better inhibition of ABTS and superoxide free radicals than that of the standard and compound 4 showed significant inhibition of protein denaturation with IC50 value of 390 mg/mL with respect to indomethacin with 110 mg/mL. From the SRB assay results, the better IC50 values was determined by compound 2 of 10.5, 11.50 and 12.50 μg/mL on HeLa, MCF-7 and FADU cancer cell lines, respectively. Thus, the outcomes revealed that the D. consimilis is a new source to treat free radicals, inflammation and cancer.