MODULATING THE BIOSYNTHESIS OF A BIOACTIVE STEROIDAL SAPONIN, CHOLESTANOL GLUCOSIDE BY LASIODIPLODIA THEOBROMAE USING ABIOTIC STRESS FACTORS

Objective: The present study investigates the modulation of cholestanol glucoside (CG) biosynthesis by Lasiodiplodia theobromae in response to oxidative, osmotic and heat shock stresses.Methods: The fungal cultures were subjected to oxidative stress by supplementing the culture media with menadione or H2O2 to the desired final concentrations. Osmotic stress was implemented by the addition of the desired concentrations of NaCl or sorbitol. For heat-shock treatments, the fungal cultures were subjected to required temperature variations. Each stress treatment was carried out at different time points so as to include different stages of fungal growth.Results: Oxidative stress enhanced CG yield by the fungus by 1.8-fold (88.3±0.6 mg/l) where as osmotic and heat shock stresses proved to be poor enhancers of CG production.Conclusions: Our findings enable a cost-effective, large scale production of CG by L. theobromae and more over throws light on the possible antioxidant activity of the compound in the organism.Â

Antioxidant activity of <i>Aulosira fertilisima</i> on CCl₄ induced hepatotoxicity in rats

52-59Free radicals cause cell injury, when they are generated in excess or when the antioxidant defense is impaired. Carbon tetrachloride (CCl4) is used as a model for liver injury. In this study antioxidant activity of ethanol extract of A. fertilisima (EEA) was investigated using CCl4 intoxicated rat liver as the experimental model. Oral administration of EEA at a dose of 100 mg/kg body weight, for 14 consecutive days, the rate of the production of antioxidant enzymes like super oxide dismutase, catalase, glutathione peroxidase and glutathione transferase in rats compared to the CCl4 treated group without any supporting treatment. Liver damage is detected by the measurement of the activities of serum enzymes like aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase and alkaline phosphatase which were released in to the blood from damaged cells. The normalization of these enzymes levels was observed in rats treated with EEA (100 mg/kg body weight) by reducing the leakage of the above enzymes in to the blood. The findings provide a rationale for further studies on isolation of active principles and its pharmacological evaluation. Protection offered by silymarin (standard reference drug) seemed relatively greater

Antioxidant and hepatoprotective activity of <i style="">Aphanizomenon flos-aquae</i> Linn against paracetamol intoxication in rats

1123-1130Paracetamol caused liver damage as evident by significant increase in the activities of aspartate and alanine transferases. There were general statistically significant losses in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione transferase and an increase in thiobarbituric acid reactive substances in the liver of paracetamol treated group compared with the control group. However, treatment with ethanol extract of A. flos-aquae (EEAFA) was able to counteract these effects. Protection offered by silymarin (standard reference drug) seemed relatively greater. The results suggest that EEAFA can act as hepatoprotective agent against paracetamol induced toxicity as an antioxidant

Antioxidant and antihepatotoxic effect of Spirulina laxissima against carbon tetrachloride induced hepatotoxicity in rats

The vast biodiversity of nature provides bioactive compounds that may be useful in the fight against chronic diseases. This study was designed to investigate the protective effects of the ethanol extract of Spirulina laxissima West (Pseudanabaenaceae) (EESL) against carbon tetrachloride (CCl4) induced hepatotoxicities in rats. Male albino rats of Sprague-Dawley strain were treated orally with the ethanol extract of S. laxissima (50, 100 mg kg(-1) body wt.) 1 h before each CCl4 administration. The ethanol extract of S. laxissima showed the maximum antioxidant property in vitro. There were statistically significant losses in the activities of antioxidant enzymes and an increase in TBARS and liver function marker enzymes in the serum of the CCl4-treated group compared with the control group. However, all the tested groups were able to counteract these effects. The antioxidant activity of the extracts might be attributable to its proton-donating ability, as evidenced by DPPH. In the present study, the decline in the level of antioxidant observed in CCl4-treated rats is a clear manifestation of excessive formation of radicals and activation of the lipid peroxidation system resulting in tissue damage. The significant increases in the concentration of antioxidant enzymes in tissues of animals treated with CCl4 + EESL indicate the antioxidant effect of EESL. This study suggests that EESL can protect the liver against CCl4-induced oxidative damage in rats, and the hepatoprotective effect might be correlated with its antioxidant and radical-scavenging effects

Isolation, Purification and Characterization of a Novel Steroidal Saponin Cholestanol Glucoside from Lasiodiplodia theobromae that Induces Apoptosis in A549 Cells

Search for novel anticancer lead molecules continues to be a major focus of cancer research due to the limitations of existing drugs such as lack of tumor selectivity, narrow therapeutic index and multidrug resistance of cancer types. Natural molecules often possess better pharmacokinetic traits compared to synthetic molecules as they continually evolve by natural selection process to interact with biological macromolecules. Microbial metabolites constitute nearly half of the pharmaceuticals in market today. Endophytic fungi, owing to its rich chemical diversity, are viewed as attractive sources of novel bioactive compounds. In the present study, we report the purification and characterization of a novel steroidal saponin, cholestanol glucoside (CG) from Saraca asoca endophytic fungus Lasiodiplodia theobromae. The compound was assessed for its cytotoxic potentialities in six human cancer cell lines, A549, PC3, HepG2, U251, MCF7 and OVCAR3. CG exhibited significant cytotoxicities towards A549, PC3 and HepG2 among which A549 cells were most vulnerable to CG treatment. However, CG treatment exhibited negligible cytotoxicity in non malignant human lung fibroblast cell line (WI-38). Induction of cell death by CG treatment in A549 cells was further investigated. CG induced the generation of reactive oxygen species (ROS) and mitochondrial membrane permeability loss followed by apoptotic cell death. Mitochondrial membrane depolarization and apoptotic cell death in CG treated A549 cells were completely blocked in presence of an antioxidant, N-acetyl cysteine (NAC). Hence it could be concluded that CG initiates apoptosis in cancer cells by augmenting the basal oxidative stress and that the generation of intracellular ROS is crucial for the induction of apoptosis

An Endophytic Fungus, Talaromyces radicus, Isolated from Catharanthus roseus, Produces Vincristine and Vinblastine, Which Induce Apoptotic Cell Death.

Endophytic fungi isolated from Catharanthus roseus were screened for the production of vincristine and vinblastine. Twenty-two endophytic fungi isolated from various tissues of C. roseus were characterized taxonomically by sequence analysis of the internal transcribed spacer (ITS) region of rDNA and grouped into 10 genera: Alternaria, Aspergillus, Chaetomium, Colletotrichum, Dothideomycetes, Eutypella, Eutypa, Flavodon, Fusarium and Talaromyces. The antiproliferative activity of these fungi was assayed in HeLa cells using the MTT assay. The fungal isolates Eutypella sp--CrP14, obtained from stem tissues, and Talaromyces radicus--CrP20, obtained from leaf tissues, showed the strongest antiproliferative activity, with IC50 values of 13.5 μg/ml and 20 μg/ml, respectively. All 22 endophytic fungi were screened for the presence of the gene encoding tryptophan decarboxylase (TDC), the key enzyme in the terpenoid indole alkaloid biosynthetic pathway, though this gene could only be amplified from T. radicus--CrP20 (NCBI GenBank accession number KC920846). The production of vincristine and vinblastine by T. radicus--CrP20 was confirmed and optimized in nine different liquid media. Good yields of vincristine (670 μg/l) in modified M2 medium and of vinblastine (70 μg/l) in potato dextrose broth medium were obtained. The cytotoxic activity of partially purified fungal vincristine was evaluated in different human cancer cell lines, with HeLa cells showing maximum susceptibility. The apoptosis-inducing activity of vincristine derived from this fungus was established through cell cycle analysis, loss of mitochondrial membrane potential and DNA fragmentation patterns

Fungal vincristine from Eutypella spp-CrP14 isolated from Catharanthus roseus induces apoptosis in human squamous carcinoma cell line-A431

Background: Catharanthus roseus, a medicinal plant, is known to produce secondary metabolites, vincristine and vinblastine, which are terpenoid indole alkaloids. Previously we have reported that Eutypella spp - CrP14 isolated from stem cutting of this plant had shown significant antiproliferative activity when tested in vitro against HeLa cell line. The present study was conducted to identify the anticancer compound responsible for the anti-proliferative activity of the fungal extract and to evaluate its in vitro anticancer and apoptotic effects. Methods: The anti-proliferative activity of the fungal anticancer compound, vincristine was analyzed by MTT assay against different cancer cell lines. We examined its efficacy of apoptotic induction on A431 cells. The parameters examined included cell cycle distribution, loss of mitochondrial membrane potential (MMP), DNA fragmentation and reactive oxygen species (ROS) generation. Results: The presence of vincristine in fungal culture filtrate was confirmed through chromatographic and spectroscopic analyses, and the amount was estimated to be 53 +/- 5.0 mu g/l. The partially purified fungal vincristine had strong cytotoxic activity towards human squamous carcinoma cells - A431 in the MTT assay. Furthermore, we showed that the fungal vincristine was capable of inducing apoptosis in A431 cells through generation of reactive oxygen species and activation of the intrinsic pathway leading to loss of MMP. Conclusions: We have demonstrated for the first time that the vincristine from Eutypella spp - CrP14 is an efficient inducer of apoptosis in A431 cells, meriting its further evaluation in vivo

Induction of apoptosis in HeLa cells treated with different concentrations of ‘fungal VCR’, as determined by annexin V-FITC/PI dual staining.

<p>A- untreated cells, B—cells + FITC, C—cells + PI, D—cells + FITC + PI, E—cells + FITC + PI + fungal VCR (5 μg/ml), F—cells + FITC + PI + fungal VCR (10 μg/ml), G—cells + FITC + PI + fungal VCR (25 μg/ml) and H—percentage of cells undergoing early apoptosis.</p