Shanmugapriya Perumal

Chemical composition, anti-angiogenic and cytotoxicity activities of the essential oils of Cymbopogan citratus (lemon grass) against colorectal and breast carcinoma cell lines

The essential oil of Cymbopogan citratus (lemon grass) was isolated by steam distillation method and subjected to cytotoxicity activity using two different cell lines, human colon carcinoma (HCT-116), breast carcinoma cell lines (MCF-7) and anti-angiogenic activity. The cytotoxicity activity study was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2,4-tetrazolium bromide] assay and anti-angiogenic activity using rat aortic ring model. The chemical composition of the essential oil was determined by gas chromatography–mass spectrometry (GC–MS) and GC–flame ionization detection (FID). Forty-one compounds, representing 88.5% of the lemon grass oil was identified and the main components were neral (29.8%) and geranial (44.6%). The free radical scavenging activity of the essential oil showed an IC50 value of 156.1 μg/mL. The results showed that essential oil of lemon grass possessed potential cytotoxic effect on HCT-116 and with the IC50 value of 27.41 ± 4.3 μg/mL comparing to MCF-7 with IC50 value of 41.90 ± 1.2 μg/mL. Significant anti-angiogenic activity of the sample was observed with 99 ± 0.8% of inhibition at 100 μg/mL.

Free Radicals Scavenging Activity, Cytotoxicity and Anti-parasitic Activity of Essential Oil of Psidium guajava L. Leaves against Toxoplasma gondii

Psidium guajava L. (family Myrtaceae), commonly known as guava, is a plant that grows in tropical and subtropical region. Different parts of the plant have been used extensively in traditional folk medicine. In the present study, the essential oil (EO) isolated from guava leaves was investigated for potential antioxidant, in vitro cytotoxicity and in vitro anti-parasitic activity against Toxoplasma gondii parasite. The antioxidant activity was evaluated through DPPH scavenging activity. Guava leaves EO served as a moderate antioxidant, with IC value of 460.56 ± 1.33 µg/mL. The in vitro cytotoxicity activity was investigated using Vero cells, while in vitro anti-parasitic assay was studied using the same cells as host for T. gondii. Growth inhibition was determined using MTT assay. Guava leaves EO was found to be not toxic to Vero cells, with 50 values of 37.54 ± 3.81 µg/mL. In the in vitro anti-T. gondii assay, guava leaves EO showed promising result with EC of 3.94 ± 0.39 µg/mL, as compared to the standard drug clindamycin (EC50 value of 6.24 ± 0.53 µg/mL). In the present study, the potential therapeutic activity of guava leaves EO may have contributed by the in vitro inhibition of free radicals associated with toxoplasmosis pathology.

Mechanism of action of isolated caffeic acid and epicatechin 3-gallate from Euphorbia hirta against Pseudomonas aeruginosa

Background: The escalating dominance of resistant Pseudomonas aeruginosa strains as infectious pathogen had urged the researchers to look for alternative and complementary drugs. Objective: The objective of this study is to address the biological targets and probable mechanisms of action underlying the potent antibacterial effect of the isolated compounds from Euphorbia hirta (L.) against P. aeruginosa. Materials and Methods: The action mechanisms of caffeic acid (CA) and epicatechin 3-gallate (ECG) on P. aeruginosa cells were investigated by several bacterial physiological manifestations involving outer membrane permeabilization, intracellular potassium ion efflux, and nucleotide leakage. Results: The findings revealed that ECG and CA targeted both cell wall and cytoplasmic membrane of P. aeruginosa. The cellular membrane destruction and ensuing membrane permeability perturbation of P. aeruginosa had led to the ascending access of hydrophobic antibiotics, release of potassium ions, and leakages of nucleotides. Conclusion: The overall study concludes that ECG and CA isolated from E. hirta possess remarkable anti-infective potentials which can be exploited as drug template for the development of new antibacterial agent against resistant P. aeruginosa pathogen. Abbreviations used: ECG: Epicatechin 3-gallate; CA: Caffeic acid; E. hirta: Euphoria hirta.

Anti-infective potential of caffeic acid and epicatechin 3-gallate isolated from methanol extract of Euphorbia hirta (L.) against Pseudomonas aeruginosa

Euphorbia hirta (L.) plant is traditionally used in Malaysia for the treatment of gastrointestinal, bronchial and respiratory ailments caused by nosocomial infectious agents. Bioactivity-guided fractionation of the methanol extract of the aerial parts of E. hirta and analysis using high-performance liquid chromatography have led to the isolation of two antibacterial compounds. These compounds were identified as caffeic acid (CA) and (–)-epicatechin 3-gallate (ECG) based on spectroscopic analyses and comparison with previously published data. Using broth microdilution method, both ECG and CA had demonstrated significant minimum inhibitory concentration of 15.6 and 31.3 μg/mL respectively, against Pseudomonas aeruginosa. Time-kill assessment of ECG and CA displayed bactericidal effect on P. aeruginosa cells.

Antiradical and Cytotoxic Activities of Varying Polarity Extracts of the Aerial Part of Euphorbia hirta L.

Euphorbia hirta is a well-known ethnomedicinal plant with diverse biological activities. The aim of the present study is to investigate the antiradical activities of various solvent extracts of the aerial part of E. hirta as well as to determine the possible cytotoxicity of these extracts. The aerial part of E. hirta was extracted with different solvent systems in order to increase polarity. The solvents used were hexane, dichloromethane (DCM), ethyl acetate (EA), ethanol (EtOH), and methanol (MeOH). The contents of total phenols and total flavonoids were analyzed by UV spectrophotometry, whereas the potential free radical-scavenging activities of the extracts were evaluated using the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), the β-carotene-linoleic acid bleaching system, and reducing power. The EtOH extract exhibited the highest total phenolic content ( mg GAE/g), and DCM extract scored the highest total flavonoid content ( mg CE/g). The MeOH extract showed a potent free radical-scavenging activity as evidenced by low EC50 at 42.81 µg/mL. Interestingly, the EtOH extract demonstrated the highest reducing power activity with EC50 value of 6.18 µg/mL. In β-carotene-linoleic acid assay, oxidation of linoleic acid was effectively inhibited by DCM extract with %. All the extracts showed no cytotoxic activity against Vero cells.

Combination of Epicatechin 3-Gallate from Euphorbia hirta and Cefepime Promotes Potential Synergistic Eradication Action against Resistant Clinical Isolate of Pseudomonas aeruginosa

Pseudomonas aeruginosa is naturally resistant to many classes of antipseudomonal antibiotics due to the species ability to easily acquire resistance. Plant-based antibacterial agent in combination with the existing antibiotic proposes an alternative treatment regimen for the eradication of resistant bacterial infections. The antibacterial effects of the isolated epicatechin 3-gallate compound from Euphorbia hirta in combination with cefepime were investigated in vitro against resistant P. aeruginosa. The fractional inhibitory concentration index of the combination was determined using checkerboard broth microdilution method. Epicatechin 3-gallate combined with cefepime had produced synergistic effect against P. aeruginosa (with average FIC index of 0.24). The MIC of epicatechin 3-gallate was effectively reduced to MIC/4, MIC/8, MIC/16, and MIC/32 in the presence of cefepime. Time-kill study of epicatechin 3-gallate combined with cefepime exhibited remarkable bactericidal activity where the eradication of P. aeruginosa occurred within 4 h of treatment. Scanning electron micrographs revealed apparent cell membrane damage and leakage of cytoplasmic contents from P. aeruginosa cells which eventually led to the cell lysis after the combination treatment of epicatechin 3-gallate and cefepime. The potential of epicatechin 3-gallate to act synergistically with cefepime against clinically resistant P. aeruginosa strain possibly will maximize the successful outcomes when choosing empirical antibiotic treatment in hospitals or health care institutions.