Photodynamic Therapy with Targeted Release of Boron-Dipyrromethene Dye from Cobalt(III) Prodrugs in Red Light.

Boron-dipyrromethene (BODIPY) dyes are promising photosensitizers for cellular imaging and photodynamic therapy (PDT) owing to their excellent photophysical properties and the synthetically tunable core. Metalation provides a convenient way to overcome the drawbacks arising from their low aqueous solubility. New photo-/redox-responsive Co(III) prodrug chaperones are developed as anticancer PDT agents for efficient cellular delivery of red-light-active BODIPY dyes. The photobiological activity of heteroleptic Co(III) complexes derived from tris(2-pyridylmethyl)amine (TPA) and acetylacetone-conjugated PEGylated distyryl BODIPY (HL1) or its dibromo analogue (HL2), [CoIII(TPA)(L1/L2)](ClO4)2 (1 and 2), are investigated. The Co(III)/Co(II) redox potential is tuned using the Co(III)-TPA scaffold. Complex 1 displays the in vitro release of BODIPY on red light irradiation. Complex 2, having good singlet oxygen quantum yield (ΦΔ âˆ¼ 0.28 in DMSO), demonstrates submicromolar photocytotoxicity to HeLa cancer cells (IC50 ≈ 0.23 µM) while being less toxic to HPL1D normal cells in red light. Cellular imaging using the emissive complex 1 shows mitochondrial localization and significant penetration into the HeLa tumor spheroids. Complex 2 shows supercoiled DNA photocleavage activity and apoptotic cell death through phototriggered generation of reactive oxygen species. The Co(III)-BODIPY prodrug conjugates exemplify new type of phototherapeutic agents with better efficacy than the organic dyes alone in the phototherapeutic window.

Clonostachys rosea, a marine algal endophyte, as an alternative source of chrysin and its anticancer effect.

Endophytic fungi were isolated from the marine green alga Chaetomorpha antennina and identified as Clonostachys rosea through molecular analysis. C. rosea was grown in a tryptophan medium for 21 days and after that, the metabolites were extracted by ethyl acetate. The ethyl acetate extract showed a high cytotoxic effect on MCF-7 cells. GC-MS analysis of the ethyl acetate extract revealed the presence of many compounds, and chrysin was one of the major compounds among them. Hence, further studies were concentrated on chrysin, as it was assumed to be the major attributor to the potent cytotoxicity, based on its high anticancer efficacies reported earlier. The fungal ethyl acetate extract had been analysed for chrysin using HPTLC and compared its Rf value with authentic chrysin and it was matched. Further, the purified fungal chrysin was structurally elucidated using techniques like LC-MS and NMR analyses. Quantification revealed that C. rosea produced 1050 mg/L of chrysin. This surplus production of chrysin was the major significance of the study. The purified fungal chrysin was found to be highly cytotoxic to MCF-7 cells with a low IC50 value 35.5 ± 0.6 µM. Furthermore, DNA fragmentation and apoptosis analysis indicated the selective inhibition of MCF-7 by DNA damage. Thus, the present study implies that C. rosea is an alternative source and new method for surplus production of chrysin in the tryptophan medium. All results indicate that the marine algae endophytic C. rosa produces chrysin, and for the first time, an excess amount of production was revealed by the study.

Curative Potential of High-Value Phytochemicals on COVID-19 Infection.

Medicinal plants and their therapeutically promising chemical compounds belonging to the valued category of 'traditional medicine' are potential remedies for various health problems. Due to their complex structure and enormous health benefits, the high-value plant-derived metabolites collectively termed as 'phytochemicals' have emerged as a crucial source for novel drug discovery and development. Indeed, several medicinal plants from diverse habitats are still in the 'underexplored' category in terms of their bioactive principles and therapeutic potential. COVID-19, infection caused by the SARS-CoV-2, first reported in November 2019, resulted in the alarming number of deaths (6.61 million), was further declared 'pandemic', and spread of the disease has continued till today. Even though the well-established scientific world has successfully implemented vaccines against COVID-19 within the short period of time, the focus on alternative remedies for long-term symptom management and immunity boosting have been increased. At this point, interventions based on traditional medicine, which include medicinal plants, their bioactive metabolites, extracts and formulations, attracted a lot of attention as alternative solutions for COVID-19 management. Here, we reviewed the recent research findings related to the effectiveness of phytochemicals in treatment or prevention of COVID-19. Furthermore, the literature regarding the mechanisms behind the preventive or therapeutic effects of these natural phytochemicals were also discussed. In conclusion, we suggest that the active plant-derived components could be used alone or in combination as an alternative solution for the management of SARS-CoV-2 infection. Moreover, the structure of these natural productomes may lead to the emergence of new prophylactic strategies for SARS-CoV-2-caused infection.

The emergence of a novel coronavirus (SARS-CoV-2) disease and their neuroinvasive propensity may affect in COVID-19 patients.

An outbreak of a novel coronavirus (SARS-CoV-2) infection has recently emerged and rapidly spreading in humans causing a significant threat to international health and the economy. Rapid assessment and warning are crucial for an outbreak analysis in response to serious public health. SARS-CoV-2 shares highly homological sequences with SARS-CoVs causing highly lethal pneumonia with respiratory distress and clinical symptoms similar to those reported for SARS-CoV and MERS-CoV infections. Notably, some COVID-19 patients also expressed neurologic signs like nausea, headache, and vomiting. Several studies have reported that coronaviruses are not only causing respiratory illness but also invade the central nervous system through a synapse-connected route. SARS-CoV infections are reported in both patients and experimental animals' brains. Interestingly, some COVID-19 patients have shown the presence of SARS-CoV-2 virus in their cerebrospinal fluid. Considering the similarities between SARS-CoV and SARS-CoV-2 in various aspects, it remains to clarify whether the potent invasion of SARS-CoV-2 may affect in COVID-19 patients. All these indicate that more detailed criteria are needed for the treatment and the prevention of SARS-CoV-2 infected patients. In the absence of potential interventions for COVID-19, there is an urgent need for an alternative strategy to control the spread of this disease.

Novel Microbial Sources of Tropane Alkaloids: First Report of Production by Endophytic Fungi Isolated from Datura metel L.

Eighteen endophytic fungi were isolated from various tissues of Datura metel and genes encoding for putrescine N-methyltransferase (PMT), tropinone reductase 1 (TR1) and hyoscyamine 6ß-hydroxylase (H6H) were used as molecular markers for PCR-based screening approach for tropane alkaloids (TAs) producing endophytic fungi. These fungi were identified taxonomically by sequence analysis of the internal transcribed spacer region (ITS1-5.8S-ITS2) and also based on morphological characteristics of the fungal spore as Colletotrichum boninense, Phomopsis sp., Fusarium solani, Colletotrichum incarnatum, Colletotrichum siamense and Colletotrichum gloeosporioides. The production of TAs hyoscyamine and scopolamine by the fungi has been ascertained using chromatography and spectroscopy methods by comparison with the standards. Among the fungi, the highest yields of hyoscyamine (3.9 mg/L) and scopolamine (4.1 mg/L) were found in C. incarnatum culture. This is the first report of endophytic fungi possess the PMT, TR1 and H6H genes and produces TAs. These endophytic fungi have significant potential to be applied in fermentation technology to meet the demands for TAs economically.

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 µg/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.

Inhibition of cancer cell proliferation and apoptosis-inducing activity of fungal taxol and its precursor baccatin III purified from endophytic Fusarium solani.

BACKGROUND: Taxol (generic name paclitaxel), a plant-derived antineoplastic agent, used widely against breast, ovarian and lung cancer, was originally isolated from the bark of the Pacific yew, Taxus brevifolia. The limited supply of the drug has prompted efforts to find alternative sources, such as chemical synthesis, tissue and cell cultures of the Taxus species both of which are expensive and yield low levels. Fermentation processes with microorganisms would be the methods of choice to lower the costs and increase yields. Previously we have reported that F. solani isolated from T. celebica produced taxol and its precursor baccatin III in liquid grown cultures J Biosci 33:259-67, 2008. This study was performed to evaluate the inhibition of proliferation and induction of apoptosis of cancer cell lines by the fungal taxol and fungal baccatin III of F. solani isolated from T. celebica. METHODS: Cell lines such as HeLa, HepG2, Jurkat, Ovcar3 and T47D were cultured individually and treated with fungal taxol, baccatin III with or without caspase inhibitors according to experimental requirements. Their efficacy on apoptotic induction was examined. RESULTS: Both fungal taxol and baccatin III inhibited cell proliferation of a number of cancer cell lines with IC50 ranging from 0.005 to 0.2 µM for fungal taxol and 2 to 5 µM for fungal baccatin III. They also induced apoptosis in JR4-Jurkat cells with a possible involvement of anti-apoptotic Bcl2 and loss in mitochondrial membrane potential, and was unaffected by inhibitors of caspase-9,-2 or -3 but was prevented in presence of caspase-10 inhibitor. DNA fragmentation was also observed in cells treated with fungal taxol and baccatin III. CONCLUSIONS: The cytotoxic activity exhibited by fungal taxol and baccatin III involves the same mechanism, dependent on caspase-10 and membrane potential loss of mitochondria, with taxol having far greater cytotoxic potential.

Naphthalene carbohydrazone based dizinc(II) chemosensor for a pyrophosphate ion and its DNA assessment application in polymerase chain reaction products.

A new naphthalene carbohydrazone based dizinc(II) complex has been synthesized and investigated to act as a highly selective fluorescence and visual sensor for a pyrophosphate ion with a quite low detection limit of 155 ppb; this has also been used to detect the pyrophosphate ion released from polymerase-chain-reaction.

Retracted: Isolation and purifications of an ambuic acid derivative compound from marine algal endophytic fungi Talaromyces flavus that induces apoptosis in MDA-MB-231 cancer cells.

In recent years, there has been a lot of buzz about the possibilities of marine microflora as a source of new therapeutic drugs. The strong anti-tumor potency of compounds found in marine resources reflects the ocean's enormous potential as a source of anticancer therapeutics. In this present investigation, an ambuic acid derivative anticancer compound was isolated from Talaromyces flavus, and its cytotoxicity and apoptosis induction potential were analyzed. T. flavus was identified through morphological and molecular analysis. The various organic solvent extracts of T. flavus grown on different growth mediums were evaluated for cytotoxicity on different cancer cell lines. The potent cytotoxicity was shown in the ethyl acetate extract of a fungal culture grown in the M1-D medium for 21 days. Furthermore, the anticancer compound was identified using preparative thin layer chromatography, followed by its purification in significant proportions using column chromatography. The spectroscopic and chromatographic analysis revealed that the structure of the purified molecules was an ambuic acid derivative. The ambuic acid derivative compound showed potent cytotoxicity on MDA-MB-231 (breast cancer cells) with an IC50 value of 26 µM and induced apoptosis in the MDA-MB-231 cells in a time-dependent and reactive oxygen species-independent manner.

Synthesis of Nickel-Chitosan Nanoparticles for Controlling Blast Diseases in Asian Rice.

Rice blast caused by Pyricularia oryzae is one of most devastating fungal diseases in rice, reducing the annual yield of rice worldwide. As an alternative to fungicide for curbing rice blast, synthesis of nickel-chitosan nanoparticles (Ni-Ch NPs) was performed with nickel chloride and assessed its efficacy in inflating plant growth and hindrance of Pyricularia oryzae (blast pathogen). Characterization of Ni-Ch NPs from SEM, TEM, and DLS analyses showed smooth- and spherical-shaped nanoparticles in the range of 20-70 nm. Colloidal stability of NPs was revealed from Zeta potential exhibiting polydispersity index of 0.22. EDX spectroscopy corroborated the presence of nickel (14.05%) in synthesized Ni-Ch NPs. A significant increase in germination and growth attributes in terms of shoot and root length and number of lateral roots over control was observed in paddy seeds on the treatment with Ni-Ch NPs. Furthermore, the application of NPs in paddy plants under glasshouse condition demonstrated a remarkable improvement in plant growth. Protein profiling of NP-treated plants revealed new polypeptides (Rubisco units) enlightening the enhanced photosynthetic rate. Also, Asian rice exhibited reduced blast symptoms on leaves treated with NPs under glasshouse condition while displaying 64% mycelia inhibition in Petri plates. All these results suggest that nickel-chitosan nanoparticles could be exploited as an effective plant growth promoter cohort in controlling rice blast disease.

Evaluation of spore inoculum and confirmation of pathway genetic blueprint of T13αH and DBAT from a Taxol-producing endophytic fungus.

Taxol (paclitaxel), a plant-derived anticancer drug, has been among the most successful anticancer drugs of natural origin. Endophytic fungi have been proposed as a prominent alternative source for Taxol and its intermediate Baccatin III, however the very low yields remain a hinderance to their commercial utilization. Significant research efforts towards this end are underway globally. Here, we report the results on our earlier reported Taxol-producing endophytic fungus, Fusarium solani from the standpoint of spores as seed inoculum and media selection for enhanced Taxol and baccatin III yields. Spores produced on M1D medium with 94.76% viability were used for further media optimization for Taxol and Baccatin III production in five different liquid media under static and shaker condition at different cultivation days. Taxol and Baccatin III when quantified through competitive inhibition enzyme immunoassay (CIEIA), showed maximum production at 136.3 µg L-1 and 128.3 µg L-1, respectively in the modified flask basal broth (MFBB) under shaking condition. Further, two important genes of this pathway, namely taxane 13α-hydroxylase (T13αH) and 10-deacetylbaccatin III-10-ß-O-acetyltransferase (DBAT) have been identified in this fungus. These findings are hoped to assist in further manipulation and metabolic engineering of the parent F. solani strain towards the enhanced production of Taxol and baccatin III.

Biochemical insights into the recombinant 10-deacetylbaccatin III-10-ß-O-acetyltransferase enzyme from the Taxol-producing endophytic fungus Lasiodiplodia theobromae.

10-deacetylbaccatin III-10-ß-O-acetyltransferase (DBAT) is a key rate-limiting enzyme of the Taxol biosynthetic pathway, which is uncharacterized in Taxol-producing endophytic fungi. Here, an open reading frame of DBAT was cloned from the Taxol-producing endophytic fungus Lasiodiplodia theobromae (LtDBAT). The LtDBAT enzyme was heterologously expressed and purified by the affinity and gel filtration chromatography methods. The molecular weight of the purified protein was 49 kDa and its identity was confirmed by western blot. The purified LtDBAT enzyme was capable of catalyzing 10-deacetylbaccatin III into baccatin III, as shown by liquid chromatography-mass spectroscopy. The mass spectra of baccatin III were identical to the authentic baccatin III. The LtDBAT enzyme was characterized and the kinetic parameters of catalysis were determined. In addition, localization of LtDBAT was performed by using confocal microscopy and the result showed that the enzyme was localized in lipid droplets. Together, this study provides biochemical insights into the fungal recombinant DBAT enzyme that is involved in the Taxol biosynthetic pathway. In the near future, engineering of the LtDBAT enzyme and the Taxol biosynthetic pathway in endophytic fungi could be an eco-friendly and economically feasible alternative source for production of Taxol and its precursors.

Correction: Impact of metal binding on the antitumor activity and cellular imaging of a metal chelator cationic imidazopyridine derivative.

Correction for 'Impact of metal binding on the antitumor activity and cellular imaging of a metal chelator cationic imidazopyridine derivative' by Mithun Roy et al., Dalton Trans., 2011, 40, 4855-4864.

Inhibition of thrombin, an unexplored function of retinoic acid.

Retinoic acid, a derivative of vitamin A, is known to possess in vivo anti-inflammatory, anti-platelet and fibrinolytic activities. We have investigated the in vitro thrombin and platelet aggregation inhibitory activities of vitamin A (retinol) and its derivatives, retinoic acid and retinaldehyde. The thrombin enzymatic assay was performed fluorimetrically to assess the inhibition of thrombin (Sigma and plasma). Retinoic acid, retinaldehyde and retinol exhibited potent inhibition of thrombin, with IC50 values of 67µg/ml, 74µg/ml and 152µg/ml, respectively for the inhibition of thrombin (Sigma); and 49µg/ml, 74µg/ml and 178µg/ml, respectively for the inhibition of thrombin (plasma). Amongst vitamin A and its derivatives, retinoic acid showed the highest inhibition of both the forms of thrombin. Vitamin A and its derivatives also displayed remarkable inhibition of platelet aggregation. This is the first report of vitamin A and its derivatives showing inhibition of thrombin and platelet aggregation in vitro.

Production of paclitaxel by Fusarium solani isolated from Taxus celebica.

A fungus was isolated from the stem cuttings of Taxus celebica, which produced paclitaxel in liquid-grown cultures. The fungus was identified as Fusarium solani based on colony characteristics, morphology of conidia and the 26S rDNA sequence. Paclitaxel was identified by chromatographic and spectroscopic comparison with authentic paclitaxel and its cytotoxic activity towards Jurkat cells in vitro.

Expression and localization of calcium-dependent protein kinase isoforms in chickpea.

Calcium-dependent protein kinases (CPKs) play important roles in multiple signal transduction pathways but the precise role of individual CPK is largely unknown. We isolated two cDNAs encoding two CPK isoforms (Cicer arietinum CPKs-CaCPK1 and CaCPK2) of chickpea. Their expression in various organs and in response to various phytohormones, and dehydration, high salt stress and fungal spore in excised leaves as well as localization in leaf and stem tissues were analyzed in this study. CaCPK1 protein and its activity were ubiquitous in all tissues examined. In contrast, CaCPK2 transcript, CaCPK2 protein and its activity were almost undetectable in flowers and fruits. Both CaCPK1 and CaCPK2 transcripts and proteins were abundant in roots but in minor quantities in leaves and stems. Of the three phytohormones tested, viz. indole-3-acetic acid (IAA), gibberellin (GA(3)) and benzyladenine (BA), only BA increased both CaCPK1 and CaCPK2 transcripts, proteins and their activities. GA(3) induced accumulation of CaCPK2 transcript and protein but CaCPK1 remained unaffected. The expression of CaCPK1 and CaCPK2 in leaves was enhanced in response to high salt stress. Treatments with Aspergillus sp. spores increased expression of CaCPK1 in chickpea leaf tissue but had no effect on CaCPK2. Excised leaves subjected to dehydration showed increase in CaCPK2 expression but not in CaCPK1. Both isoforms were located in the plasma membrane (PM) and chloroplast membrane of leaf mesophyll cells as well as in the PM of stem xylem parenchyma cells. These results suggest specific roles for CaCPK isoforms in phytohormone/defense/stress signaling pathways.

Heterologous expression and biochemical characterization of two calcium-dependent protein kinase isoforms CaCPK1 and CaCPK2 from chickpea.

In plants, calcium-dependent protein kinases (CPKs) constitute a unique family of enzymes consisting of a protein kinase catalytic domain fused to carboxy-terminal autoregulatory and calmodulin-like domains. We isolated two cDNAs encoding calcium-dependent protein kinase isoforms (CaCPK1 and CaCPK2) from chickpea. Both isoforms were expressed as fusion proteins in Escherichia coli. Biochemical analyses have identified CaCPK1 and CaCPK2 as Ca(2+)-dependent protein kinases since both enzymes phosphorylated themselves and histone III-S as substrate only in the presence of Ca(2+). The kinase activity of the recombinant enzymes was calmodulin independent and sensitive to CaM antagonists W7 [N-(6-aminohexyl)-5-chloro-1-naphthalene sulphonamide] and calmidazoilum. Phosphoamino acid analysis revealed that the isoforms transferred the gamma-phosphate of ATP only to serine residues of histone III-S and their autophosphorylation occurred on serine and threonine residues. These two isoforms showed considerable variations with respect to their biochemical and kinetic properties including Ca(2+) sensitivities. The recombinant CaCPK1 has a pH and temperature optimum of pH 6.8-8.6 and 35-42 degrees C, respectively, whereas CaCPK2 has a pH and temperature optimum of pH 7.2-9 and 35-42 degrees C, respectively. Taken together, our results suggest that CaCPK1 and CaCPK2 are functional serine/threonine kinases and may play different roles in Ca(2+)-mediated signaling in chickpea plants.

Enhanced cytotoxic and apoptosis inducing activity of lycopene oxidation products in different cancer cell lines.

Currently, upon understanding the metabolomics of carotenoids, it is important to address the key role of carotenoid derived products. In this regard, aim of the study was to elucidate and explore the role of lycopene (LYC) oxidative products generated through autoxidation (AOL) or chemical (KMnO4) oxidation (COL) against proliferation of selected cancer cells. Preliminary, we investigated the effect of LYC on cell viability of various cancer cell lines (PC-3, MCF-7, A431, HepG2, HeLa and A549). Based on the results of LYC treatment on cell cytotoxicity levels, MCF-7, PC-3 and HeLa cell lines were further tested with AOL and COL products. The decreased cell viability with depleted GSH and increased MDA levels were observed when treated with COL products than control, LYC and AOL. In addition, COL products increased ROS levels and percent apoptosis. The typical morphological changes and nuclear condensations showed that COL products have anti-proliferation and apoptosis inducing activity. Based on results, we hypothesized that ROS generation by LYC oxidation products may be one of intermediate step involved in apoptosis. The redox status and therapeutic approach of COL products in modulating ROS and induction of apoptosis in cancer cells were reported for the first time, to our knowledge. To conclude, COL products involves in cancer growth inhibition efficiently than intact LYC and AOL. Hence, there is a great potential for synthesizing or producing such carotenoid oxidation products to augment cancer complication.

Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum.

Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 µM and 120 µM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 µM and 1.7 µM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1.

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.