New ring-A modified cycloartane triterpenoids from Dysoxylum malabaricum bark: Isolation, structure elucidation and their cytotoxicity

The Genus Dysoxylum (Meliaceae) consists of approximately 80 species that are abundant in structurally diverse triterpenoids. The present study focused on isolating new triterpenoids from the bark of Dysoxylum malabaricum, one of the predominant species of Dysoxylum present in India. The methanol-dichloromethane bark extract was subjected to LCMS profiling followed by silica gel column chromatography and HPLC analysis to target new compounds. Two new ring A-modified cycloartane-type triterpenoids (1 and 2) were isolated from the bark extract. Spectroscopic methods like NMR, HRESIMS data, and electronic circular dichroism calculations elucidated the structuresandabsolute configurations of the isolated compounds. These compounds were evaluated for their cytotoxic potential against breast cancer cells and displayed notable cytotoxicity. Compound 1 exhibited the highest cytotoxicity against the MDA-MB-231 cells and induced apoptotic cell death. Also, it was able to inhibit glucose uptake and increase nitric oxide production in breast cancer cells.

New cycloartane triterpenoids from Dysoxylum malabaricum and their cytotoxic evaluation

The cytotoxic dichloromethane-methanol bark extract of Dysoxylum malabaricum was subjected to bioassay-guided fractionation, followed by systematic dereplication to focus on the identification of new compounds. From the bark of Dysoxylum malabaricum, two new cycloartane-type triterpenoids were isolated in addition to two previously known triterpenoids. The structures and absolute configurations of the isolated compounds were elucidated unambiguously via NMR, HRESIMS data, and electronic circular dichroism calculations. The isolated compounds were tested for their cytotoxic potential against the panel of breast, lung, and hypopharynx cancer cell lines and displayed notable cytotoxicity against breast cancer cell lines. Compound 3 exhibited the most potent cytotoxic effect with an IC50 14 µM against MCF-7 cell lines and induced cell cycle arrest. Through western blot and cell cycle analysis, it was revealed that compound 3 halts the G0/G1 phase of the cell cycle by inhibiting CDC20 and CDC25 enzymes.

Opening the floodgates for invasion-modelling the distribution dynamics of invasive alien fishes in India

Invasive alien species have become the second major threat to biodiversity affecting all three major ecosystems (terrestrial, marine, and freshwater). Increasing drivers such as habitat destruction, expanding horticulture and aquaculture industries, and global pet and food trade have created pathways for exotic species to be introduced leading to severe impacts on recipient ecosystems. Although relatively less studied than terrestrial ecosystems, freshwater ecosystems are highly susceptible to biological invasions. In India, there has been a noticeable increase in the introduction of alien fish species in freshwater environments. In the current study, we aimed to understand how climate change can affect the dynamics of the biological invasion of invasive alien fishes in India. We also evaluated the river-linking project's impact on the homogenization of biota in Indian freshwater bodies. We used species occurrence records with selected environmental variables to assess vulnerable locations for current and future biological invasion using species distribution models. Our study has identified and mapped the vulnerable regions to invasion in India. Our research indicates that the interlinking of rivers connects susceptible regions housing endangered fish species with invasive hotspots. Invasive alien fishes from the source basin may invade vulnerable basins and compete with the native species. Based on the results, we discuss some of the key areas for the management of these invasive alien species in the freshwater ecosystems.

Endemicity and radiation in waterfalls of the Western Ghats: The genus Cremnoconchus (Gastropoda: Littorinidae)

Snails of the genus Cremnoconchus - the only freshwater members of the gastropod family Littorinidae - are endemic to the spray zones of numerous waterfalls in the Western Ghats of India. Cremnoconchus consists of nine described and possibly numerous undescribed species as many of these appear to be restricted to specific waterfalls. This is the first attempt at resolving the relationships between the various species in this genus and establishing its monophyly in the family. Further, we also undertake species delimitation analysis to characterize cryptic diversity in this group. Phylogenetic analyses based on nuclear and mitochondrial genes support the monophyly of Cremnoconchus within the family. A fossil-calibrated Bayesian time tree suggests that this freshwater lineage diverged from its marine counterparts around 90.40 million years ago. The separation of Cremnoconchus from its marine ancestors might have been facilitated by the break-up of Gondwana or fluctuating sea levels during this period. Species delimitation analysis retrieved 12 potentially undescribed species in this group. These species formed two distinct clades in the phylogeny, one largely confined to the northern Western Ghats and the other to the central Western Ghats. Species belonging to the northern and central Western Ghats seem to have separated around 56.11 mya, i.e. after the northern Western Ghats were formed. Additionally, spatial isolation due to the patchiness of suitable habitats (waterfalls) and low mobility might have facilitated their diversification.

Can species distribution models and molecular tools help unravel disjunct distribution of Rhododendron arboreum?

The apparent absence of Himalayan low-elevation taxa in the central Indian region and resumption of their distribution in the high elevation of Western Ghats has puzzled biogeographers for several decades. Many theories have been proposed to explain this but attempts remain futile owing to insufficient empirical support. Here, we have employed a montane tree species, Rhododendron arboreum to investigate this pattern by integrating past ecological niche modelling with molecular signatures. Reconstruction of paleo-ecological niche from interglacial to Last Glacial Maxima (LGM) portrayed a gradual depletion of vegetation cover with extreme impoverishment in the Holocene. A similar pattern was also reflected from genetic signatures; population history revealed a very recent split between the Himalayas and Western Ghats in the late Quaternary. A few other tree species exhibiting the same disjunction demonstrated a similar modification of paleo-ecological niche from last interglacial. The study clearly indicated that the populations in the Western Ghats to be a relictual remnants of a once continuous distribution of R. arboreum.

Inhibition of plant pathogenic fungi by endophytic Trichoderma spp. through mycoparasitism and volatile organic compounds

Antagonism of plant pathogenic fungi by endophytic fungi is a well-known phenomenon. In plate assays, the antagonism could be due to mycoparasitism, competition for space or antibiosis, involving a chemical diffusate, or a volatile organic compound (VOC). In this study, we demonstrate that besides mycoparasitism, VOCs play a major role in antagonism of pathogenic fungi by four endophytic fungi belonging to the genus Trichoderma. Using a double-plate assay, we show that all the four endophytic Trichoderma species significantly inhibited mycelial growth of three of the four pathogens, (Sclerotinia sclerotiorum-TSS, Sclerotium rolfsii-CSR and Fusarium oxysporum-CFO), while that of Macrophomina phaseolina-CMP was not affected. GC-MS analysis of the pure cultures of one of the endophytic fungi studied, namely, Trichoderma longibrachiatum strain 2 (Acc. No. MK751758) and the pathogens, F. oxysporum-CFO and M. phaseolina-CMP revealed the presence of several VOCs including hydrocarbons, alcohols, ketones, aldehydes, esters, acids, ethers and different classes of terpenes. In mixed double plates, where the endophyte was grown along with either of the two plant pathogens, F. oxysporum-CFO or M. phaseolina-CMP, there was an induction of a number of new VOCs that were not detected in the pure cultures of either the endophyte or the pathogens. Several of these new VOCs are reported to possess antifungal and cytotoxic activity. We discuss these results and highlight the importance of such interactions in endophyte-pathogen interactions.

An endophyte from salt-adapted Pokkali rice confers salt-tolerance to a salt-sensitive rice variety and targets a unique pattern of genes in its new host

Endophytes, both of bacterial and fungal origin, are ubiquitously present in all plants. While their origin and evolution are enigmatic, there is burgeoning literature on their role in promoting growth and stress responses in their hosts. We demonstrate that a salt-tolerant endophyte isolated from salt-adapted Pokkali rice, a Fusarium sp., colonizes the salt-sensitive rice variety IR-64, promotes its growth under salt stress and confers salinity stress tolerance to its host. Physiological parameters, such as assimilation rate and chlorophyll stability index were higher in the colonized plants. Comparative transcriptome analysis revealed 1348 up-regulated and 1078 down-regulated genes in plants colonized by the endophyte. Analysis of the regulated genes by MapMan and interaction network programs showed that they are involved in both abiotic and biotic stress tolerance, and code for proteins involved in signal perception (leucine-rich repeat proteins, receptor-like kinases) and transduction (Ca2+ and calmodulin-binding proteins), transcription factors, secondary metabolism and oxidative stress scavenging. For nine genes, the data were validated by qPCR analysis in both roots and shoots. Taken together, these results show that salt-adapted Pokkali rice varieties are powerful sources for the identification of novel endophytes, which can be used to confer salinity tolerance to agriculturally important, but salt-sensitive rice varieties.

A review on the conservation genetic studies of Indian amphibians and their implications on developing strategies for conservation

Amphibians show a very high level of diversity and endemism and are facing global declines from the past few decades. Studies have shown that the molecular tools can be helpful in their conservation efforts. In India, more than 80% of amphibians are endemic and most show a narrow range of distribution. Most of the Indian amphibians lack information on their genetic diversity. In this study, were view the overall trend on amphibian studies in India with the specific focus on conservation genetics. Overall, of the 173 studies, only 14 dealt with the conservation of amphibians through genetic tools and five studies estimated the genetic diversity or gene structure. Here, we discuss the gaps and provide future directions on how genetic studies can be helpful in Indian amphibian conservation.

Development and characterization of microsatellite markers for Phyllanthus emblica Linn., important nontimber forest product species

Phyllanthus emblica and P. indofischeri, commonly known as the Indian gooseberry, are important nontimber forest product (NTFP) species widely distributed across the Indian subcontinent. The fruits of these species are rich in vitamin C and are used in the preparation of a number of herbal medicines for treating a wide range of disorders. Due to the increased demand, they have been harvested extensively and form a major source of income for the forest-dwelling communities living in southern India. There are limited studies to understand the impact of harvesting on the genetic structure of these species. In this study, 15 polymorphic microsatellite markers have been developed for P. emblica and were characterized by screening 20 individuals each of P. emblica and P. indofischeri. The number of alleles per locus ranged 2-9 for P. emblica and 2-11 for P. indofischeri. The observed and expected heterozygosity of P. emblica ranged 0-1 and 0.401-0.825, respectively. Similarly, the observed and expected heterozygosity of P. indofischeri ranged 0.5-1 and 0.366-0.842, respectively. Cross-amplification of the designed primers was assessed with seven related Phyllanthus species. The microsatellite markers developed can be used for studying the population genetic structure, gene flow and genetic diversity of P. emblica and P. indofischeri.

Assessment of adulteration in raw herbal trade of important medicinal plants of India using DNA barcoding

A number of studies have shown that there could be widespread substitution and/or adulteration (hereafter referred to as substitution) in raw herbal trade of medicinal plants. Substitution could potentially endanger the health and safety of the consumers. In this study, the extent of adulteration in raw herbal trade of 30 important medicinal plants in South India was analyzed. Biological reference material (BRM) consisting of taxonomically authenticated samples of each of the 30 species along with 14 other co-occurring and congeneric allied species that are likely to be used in adulteration was established. DNA barcode signatures of 124 BRM using two candidate regions, nr-ITS and psbA-trnH were identified. A total of 203 herbal trade samples representing the 30 medicinal plant species were collected from 34 locations in South India. Using the DNA barcode sequences of the BRM as reference, the analysis indicated that the substitution ranged from 20 to 100%. Overall, approximately 12% of the market samples were adulterated. Considering the potential health hazard that such adulteration can cause, the need for a national regulatory framework that can authenticate and regulate raw herbal trade in the country is discussed.

Camptothecin-producing endophytic bacteria from Pyrenacantha volubilis Hook. (Icacinaceae): A possible role of a plasmid in the production of camptothecin

BACKGROUND

Camptothecin (CPT), a quinoline alkaloid, is a potent inhibitor of eukaryotic topoisomerase I. Because of this property, several derivatives of CPT are used as chemotherapeutic agents. CPT is produced by several plant species belonging to the Asterid clade as well as by a number of endophytic fungal associates of these plants. In this study, we report the production of CPT by four bacterial endophytes and show the possible role of a plasmid in the biosynthesis of CPT.

METHODS

Endophytic bacteria were isolated from leaves, stems and fruits of Pyrenacantha volubilis Hook. (Icacinanceae). The bacterial isolates were purified and analyzed for production of CPT by ESI-MS/MS and NMR analysis. Bacterial identity was established based on the morphology and 16s rRNA sequence analysis. Crude extracts of the bacterial endophytes were evaluated for their cytotoxicity using colon cancer cell lines. The role of plasmid in the production of CPT was studied by purging the plasmid, using acriflavine, as well as reconstituting the bacteria with the plasmid.

RESULTS

Four bacterial isolates, Bacillus sp. (KP125955 and KP125956), Bacillus subtilis (KY741853) and Bacillus amyloliquefaciens (KY741854) were found to produce CPT in culture. Both based on ESI-MS/MS and NMR analysis, the identity of CPT was found to be similar to that produced by the host plant. The CPT was biologically active as evident by its cytotoxicity against colon cancer cell line. The production of CPT by the endophyte (Bacillus subtilis, KY741853) attenuated with sub-culture. A likely role of a plasmid in the production of CPT was established. A 5 kbp plasmid was recovered from the bacteria. Bacterial isolate cured of plasmid failed to produce CPT.

CONCLUSION

Our study implies a possible role of a plasmid in the production of CPT by the endophytic bacteria and opens up further work to unravel the exact mechanisms that might be involved.

Assigning conservation value and identifying hotspots of endemic rattan diversity in the Western Ghats, India

Rattans, or canes, are one of the most important non-timber forest products supporting the livelihood of many forest-dwelling communities in South and North-eastern India. Due to increased demand for rattan products, rattans have been extracted indiscriminately from the Western Ghats, a 1600-km mountain chain running parallel to the west coast of India. Extensive harvesting, loss of habitat and poor regeneration has resulted in dwindling rattan populations, necessitating an urgent attempt to conserve existing rattan resources. In this study, using niche-modelling tools, an attempt has been made to identify areas of high species richness of rattans in the Western Ghats, one of the mega-diversity regions of the world. We have also developed conservation values for 21 economically important and endemic rattans of the Western Ghats. We identified at least two to three sites of extremely high species richness outside the existing protected area network that should be prioritized for in situ conservation. This study emphasizes the need to develop strategies for the long-term conservation of rattans in the Western Ghats, India.

Redescription and Range Extension of <i>Microhyla</i> <i>sholigari</i> Dutta &amp; Ray (Amphibia: Anura: Microhylidae) from South West India

Microhyla sholigari is an endangered frog described in the year 2000. The original description was based on non-adult types and lacked information on several morphological characters, call structure, genetic material and photographs of the animal in life. The absence of such information posed challenges in field identification of this species. Since the original description, there is one other reported sighting of this species from Kerala in 2001. We encountered specimens that we confer to this species based on morphological similarity to the subadult holotype, from several new localities within and outside the Western Ghats of Karnataka. We here redescribe the species based on additional adult vouchers, provide molecular data, describe the advertisement call and report a range extension. Based on its current distribution, we assess the threat status of the species and suggest listing it as Least Concern according to IUCN Red List criteria. Our paper bridges an important gap in the knowledge of the genus Microhyla in India and highlights the importance of systematic surveys in documenting and understanding amphibian diversity in the region.

Modeling the impact of climate change on wild Piper nigrum (Black Pepper) in Western Ghats, India using ecological niche models

The center of diversity of Piper nigrum L. (Black Pepper), one of the highly valued spice crops is reported to be from India. Black pepper is naturally distributed in India in the Western Ghats biodiversity hotspot and is the only known existing source of its wild germplasm in the world. We used ecological niche models to predict the potential distribution of wild P. nigrum in the present and two future climate change scenarios viz (A1B) and (A2A) for the year 2080. Three topographic and nine uncorrelated bioclim variables were used to develop the niche models. The environmental variables influencing the distribution of wild P. nigrum across different climate change scenarios were identified. We also assessed the direction and magnitude of the niche centroid shift and the change in niche breadth to estimate the impact of projected climate change on the distribution of P. nigrum. The study shows a niche centroid shift in the future climate scenarios. Both the projected future climate scenarios predicted a reduction in the habitat of P. nigrum in Southern Western Ghats, which harbors many wild accessions of P. nigrum. Our results highlight the impact of future climate change on P. nigrum and provide useful information for designing sound germplasm conservation strategies for P. nigrum.

Microhyla laterite sp. nov., A New Species of Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae) from a Laterite Rock Formation in South West India

In recent times, several new species of amphibians have been described from India. Many of these discoveries are from biodiversity hotspots or from within protected areas. We undertook amphibian surveys in human dominated landscapes outside of protected areas in south western region of India between years 2013-2015. We encountered a new species of Microhyla which is described here as Microhyla laterite sp. nov. It was delimited using molecular, morphometric and bioacoustics comparisons. Microhyla laterite sp. nov. appears to be restricted to areas of the West coast of India dominated by laterite rock formations. The laterite rock formations date as far back as the Cretaceous-Tertiary boundary and are considered to be wastelands in-spite of their intriguing geological history. We identify knowledge gaps in our understanding of the genus Microhyla from the Indian subcontinent and suggest ways to bridge them.

Integrative Taxonomic Approach for Describing a New Cryptic Species of Bush Frog (Raorchestes: Anura: Rhacophoridae) from the Western Ghats, India

A new cryptic species of bush frog Raorchestes honnametti sp. nov. is described from the south-eastern part of the Western Ghats, India. This newly described species belongs to the Charius clade and is morphologically similar to other clade members--R. charius and R. griet. Therefore, an integrative taxonomic approach based on molecular and bioacoustic analysis along with morphology was used to delimit the new species. Raorchestes honnametti sp. nov., is currently known only from Biligiri Rangaswamy Temple Tiger Reserve, a part of Biligiri Rangaswamy horst mountain range (a mountain formed due movement of two faults) formed during the Late Quaternary period (1.8-2.58 Ma). Discovery of cryptic species from a highly speciose and well-studied genus Raorchestes hints at the possible existence of several more cryptic species in this genus. We discuss the possible reasons for crypsis and emphasize the need for continued systematic surveys of amphibians across the Western Ghats.

Restoration of camptothecine production in attenuated endophytic fungus on re-inoculation into host plant and treatment with DNA methyltransferase inhibitor

Fungal endophytes inhabit living tissues of plants without any apparent symptoms and in many cases are known to produce secondary metabolites similar to those produced by their respective host plants. However on sub-culture, the endophytic fungi gradually attenuate their ability to produce the metabolites. Attenuation has been a major constraint in realizing the potential of endophytic fungi as an alternative source of plant secondary metabolites. In this study, we report attempts to restore camptothecine (CPT) production in attenuated endophytic fungi isolated from CPT producing plants, Nothapodytes nimmoniana and Miquelia dentata when they are passed through their host plant or plants that produce CPT and when treated with a DNA methyl transferase inhibitor. Attenuated endophytic fungi that traversed through their host tissue or plants capable of synthesizing CPT, produced significantly higher CPT compared to the attenuated fungi. Attenuated fungus cultured in the presence of 5-azacytidine, a DNA methyltransferase inhibitor, had an enhanced CPT content compared to untreated attenuated fungus. These results indicate that the attenuation of CPT production in endophytic fungi could in principle be reversed by eliciting some signals from plant tissue, most likely that which prevents the methylation or silencing of the genes responsible for CPT biosynthesis.

Ambient ionization mass spectrometry imaging of rohitukine, a chromone anti-cancer alkaloid, during seed development in Dysoxylum binectariferum Hook.f (Meliaceae)

Rohitukine, a chromone alkaloid, possesses anti-inflammatory, anti-cancer and immuno-modulatory properties. It has been reported from four species, belonging to the families, Meliaceae and Rubiaceae. Stem bark of Dysoxylum binectariferum (Meliaceae) accumulates the highest amount of rohitukine (3-7% by dry weight). In this study, we examine the spatial and temporal distribution of rohitukine and related compounds during various stages of seed development in D. binectariferum using desorption electrospray ionization mass spectrometry imaging (DESI MSI). Rohitukine (m/z 306.2) accumulation increased from early seed development to seed maturity stage. The spatial distribution of rohitukine was largely restricted to the cotyledonary tissue followed by the embryo and least in the seed coat. Besides rohitukine, rohitukine acetate (m/z 348.2) and glycosylated rohitukine (m/z 468.2) were also detected, both through mass fragmentation and exact mass analysis through Orbitrap mass spectrometry. These results indicate a dynamic pattern of chromane alkaloid accumulation through seed development in D. binectariferum.

Mud-packing frog: a novel breeding behaviour and parental care in a stream dwelling new species of Nyctibatrachus (Amphibia, Anura, Nyctibatrachidae)

Reproductive modes are diverse and unique in anurans. Selective pressures of evolution, ecology and environment are attributed to such diverse reproductive modes. Globally forty different reproductive modes in anurans have been described to date. The genus Nyctibatrachus has been recently revised and belongs to an ancient lineage of frog families in the Western Ghats of India. Species of this genus are known to exhibit mountain associated clade endemism and novel breeding behaviours. The purpose of this study is to present unique reproductive behaviour, oviposition and parental care in a new species Nyctibatrachus kumbara sp. nov. which is described in the paper. Nyctibatrachus kumbara sp. nov. is a medium sized stream dwelling frog. It is distinct from the congeners based on a suite of morphological characters and substantially divergent in DNA sequences of the mitochondrial 16S rRNA gene. Males exhibit parental care by mud packing the egg clutch. Such parental care has so far not been described from any other frog species worldwide. Besides this, we emphasize that three co-occurring congeneric species of Nyctibatrachus, namely N. jog, N. kempholeyensis and Nyctibatrachus kumbara sp. nov. from the study site differ in breeding behaviour, which could represent a case of reproductive character displacement. These three species are distinct in their size, call pattern, reproductive behaviour, maximum number of eggs in a clutch, oviposition and parental care, which was evident from the statistical analysis. The study throws light on the reproductive behaviour of Nyctibatrachus kumbara sp. nov. and associated species to understand the evolution and adaptation of reproductive modes of anurans in general, and Nyctibatrachus in particular from the Western Ghats.

Rohitukine, a chromone alkaloid and a precursor of flavopiridol, is produced by endophytic fungi isolated from Dysoxylum binectariferum Hook.f and Amoora rohituka (Roxb).Wight & Arn

Rohitukine, a chromone alkaloid, has gained considerable international attention in recent years because of its novel semi-synthetic derivative, flavopiridol and P-276-00. Both these molecules are in advanced stages of clinical development and trial for cancer treatment. Recently, flavopiridol was approved as an orphan drug for treatment of chronic lymphocytic leukemia cancer. The natural occurrence of rohitukine is restricted to only four plant species, Amoora rohituka and Dysoxylum binectariferum (both from the Meliaceae family) and from Schumanniophyton magnificum and Schumanniophyton problematicum (both from the Rubiaceae family). Recently, an endophytic fungi isolated from D. binectariferum was reported to produce rohitukine in culture. In this study, we report the production of rohitukine and its subsequent attenuation by endophytic fungi, Fusarium oxysporum (MTCC-11383), Fusarium oxysporum (MTCC-11384) and Fusarium solani (MTCC-11385), all isolated from D. binectariferum and Gibberella fujikuroi (MTCC-11382) isolated from Amoora rohituka. The fungal rohitukine which was analyzed by HPLC, LC-MS and LC-MS/MS was identical to reference rohitukine and that produced by the plant. The rohitukine content in the mycelial samples ranged from 192.78μg to 359.55μg100g(-1) of dry weight of and in broth it ranged from 14.10 to 71.90μg100ml(-1). In all the fungal cultures, the production declined from first to fourth sub-culture. Studies are underway to unravel the mechanism by which the fungi produce the host metabolite in culture.

Isolation of endophytic bacteria producing the anti-cancer alkaloid camptothecine from Miquelia dentata Bedd. (Icacinaceae)

Camptothecine (CPT), a quinoline alkaloid, is a potent inhibitor of eukaryotic topoisomerase I. Because of this activity, several semi-synthetic derivatives of CPT are in clinical use against ovarian and small lung cancers. Together with its derivatives, CPT is the third largest anti-cancer drug in the world market. CPT is produced by several plant species belonging to the Asterid clade. In the recent past, several studies have reported the production of CPT by endophytic fungal associates of some of these plant species. In this paper, we report the production of CPT by endophytic bacteria isolated from Miquelia dentata Bedd. (Icacinaceae). Besides CPT, the bacteria also produced 9-methoxy CPT (9-MeO-CPT), in culture, independent of the host tissue. The chemical nature of CPT and 9-MeO-CPT was determined by LC-MS and ESI-MS/MS analysis, and was shown to be similar to that produced by the host tissue. One of the bacterial isolates examined, showed indications of attenuation of CPT production through sub-culture. This is the first report of production of CPT by endophytic bacteria. The identity of the bacteria was ascertained by Gram staining and 16s rRNA sequencing. We discuss the possible mechanisms that might be involved in the synthesis of CPT by endophytic bacteria.

New plant sources of the anti-cancer alkaloid, camptothecine from the Icacinaceae taxa, India

In this study, the production of camptothecine and its derivatives, in thirteen species of the family Icacinaceae, namely, Apodytes dimidiata, Codiocarpus andamanicus, Gomphandra comosa, Gomphandra coriacea, Gomphandra polymorpha, Gomphandra tetrandra, Iodes cirrhosa, Iodes hookeriana, Miquelia dentata, Miquelia kleinii, Natsiatum herpeticum, Pyrenacantha volubilis and Sarcostigma kleinii is reported. Seeds of M. dentata were found to produce the highest content of camptothecine (1.0-1.4% by dry weight of seeds). Full scan LC-MS and ESI-MS/MS analysis of M. dentata revealed, besides camptothecine, a number of other derivatives, namely, 10-hydroxycamptothecine, 9-methoxycamptothecine, 20-deoxycamptothecine. Crude extract preparations of the seeds of M. dentata were effective against a breast cancer cell line (IC50=3.82 μg/ml for MDA MB273 cell lines) and two ovarian cancer cell lines (IC50=2.8 μg/ml for NCI/ADR-RES and 4.5 μg/ml for SKOV). These results are the first reports of camptothecine and its derivatives in these species and offer rich alternative plant sources for the anticancer compound, camptothecine.

Study on incidence of bleeding in hospitalized patients after antithrombotic therapy at a tertiary care hospital

OBJECTIVES

To monitor the different antithrombotic drug combinations, determine the incidence, magnitude of bleeding and the association of HAS-BLED risk scoring schema with the magnitude of bleeding as defined using TIMI bleeding criteria.

METHODS

A prospective observational study in a cohort of patients for a period of 8 months, at one of the tertiary care center-Krishna Institute of Medical Sciences, Hyderabad, was conducted. Consecutive patients were enrolled and followed from the date of admission till the adverse events are perceived/date of discharge. Pearson Correlation Statistics (Fisher's z Transformation) is applied to assess the association between HAS-BLED risk factors and the total risk score with bleeding criteria.

RESULTS

A total of 400 cases were collected during the 8-month study period, of which 372 satisfied the inclusion criteria. Among them 34 (9.1%) bleeding cases were reported with mean (+/- SD) age of 57.8 (+/- 14.19) years. Bleeding occurred mostly in males 79.4% and a HAS-BLED Score of > or = 3 has been observed in 67.6% (n = 23) patients out of 34 bled patients. Two antiplatelets + One anticoagulant is the most common combination which caused bleeding in 41.2% (n = 14). Stroke history, bleeding predisposition, labile INR's are the HAS-BLED risk factors which are significant (< 0.05) with the TIMI Bleeding Criteria.

CONCLUSION

There was a linear correlation between the HAS-BLED risk score and the TIMI bleeding criteria-higher the risk score the more frequent is the incidence of major bleeding. A HAS-BLED risk score of > or = 3 is associated with TIMI major bleeding.

Hepatoprotective activity of Indian Phyllanthus

CONTEXT

Phyllanthus (Euphorbiaceae) species are traditionally well-known for their medicinal properties including hepatoprotective activity.

OBJECTIVE

The study assessed the hepatoprotective and antioxidant activities of 11 Phyllanthus species, P. amarus Schumach., P. urinaria L., P. debilis Klein ex Willd, P. tenellus Roxb., P. virgatus G. Forst., P. maderaspatensis L., P. reticulatus Poir., P. polyphyllus Willd., P. emblica L., P. indofischerii Bennet. and P. acidus (L.) Skeels.

MATERIALS AND METHODS

The dried leaves and stems of each plant species were extracted in methanol and successively in water. The extracts were screened for hepatoprotective activity at a concentration of 50 µg/mL against tert-butyl hydroperoxide (t-BH) induced toxicity in HepG2 cells. Seven extracts from five species that showed hepatoprotective activity were assessed for their 50% effective concentration (EC₅₀) values and their antioxidant activity using a DPPH assay. Phyllanthin and hypophyllanthin contents were also determined in these Phyllanthus species.

RESULTS

The methanol extracts of P. polyphyllus, P. emblica and P. indofischeri showed high levels of hepatoprotective activity with EC₅₀ values of 12, 19 and 28 µg/mL and IC₅₀ of 3.77, 3.38 and 5.8 µg/mL for DPPH scavenging activity respectively against an IC₅₀ of 3.69 µg/mL for ascorbic acid. None of these activities could be attributed to phyllanthin and hypophyllanthin.

DISCUSSION AND CONCLUSION

The hepatoprotective and antioxidant activities of P. indofischeri are demonstrated for the first time in literature. The study also confirms the hepatoprotective and antioxidant activities of leaves of P. emblica and P. polyphyllus. The molecule(s) responsible for the activities is being investigated.

Biodiversity and chemodiversity: future perspectives in bioprospecting

Biological diversity and its constituent chemical diversity have served as one of the richest sources of bioprospecting leading to the discovery of some of the most important bioactive molecules for mankind. Despite this excellent record, in the recent past, however, bioprospecting of biological resources has met with little success; there has been a perceptible decline in the discovery of novel bioactive compounds. Several arguments have been proposed to explain the current poor success in bioprospecting. Among them, it has been argued that to bioprospect more biodiversity may not necessarily be productive, considering that chemical and functional diversity might not scale with biological diversity. In this paper, we offer a critique on the current perception of biodiversity and chemodiversity and ask to what extent it is relevant in the context of bioprospecting. First, using simple models, we analyze the relation among biodiversity, chemodiversity and functional redundancies in chemical plans of plants and argue that the biological space for exploration might still be wide open. Second, in the context of future bioprospecting, we argue that brute-force high throughput screening approaches alone are insufficient and cost ineffective in realizing bioprospecting success. Therefore, intelligent or non-random approaches to bioprospecting need to be adopted. We review here few examples of such approaches and show how these could be further developed and used in the future to accelerate the pace of discovery.

Stylish lengths: mate choice in flowers

The styles of flowers may represent an arena for pollen competition in the race to fertilize ovules. Accordingly, selection should favour a longer 'race' to better discriminate among variable pollen by increasing style length. Sampling across a taxonomically diverse range of wild and outcrossed species, we found that the distribution of style lengths within plants were skewed towards longer styles, as predicted. In self-pollinated domesticated species, where discrimination among pollen is less important, we found no such pattern. We conclude that style length is under directional selection towards longer styles as a mechanism for mate choice among pollen of variable quality.

Assessing species admixtures in raw drug trade of Phyllanthus, a hepato-protective plant using molecular tools

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus (Euphorbiaceae) species are well known for their hepato-protective activity and are used in several ethno-medicines in indigenous health care systems in India.

AIM OF THE STUDY

To assess species admixtures in raw drug trade of Phyllanthus using morphological and DNA barcoding tools.

MATERIALS AND METHODS

Samples of Phyllanthus used in raw drug trade were obtained from 25 shops in southern India. Species admixtures in the samples were assessed by identifying species using morpho-taxonomic keys. These identities were further validated by developing species specific DNA barcode signatures using the chloroplast DNA region, psbA-trnH. DNA from the market samples were extracted and amplified using the forward (psbAF - GTTATGCATGAACGTAATGCTC) and reverse primer (trnHR - CGCGCATGGTGGATTCACAAATC). The amplified products were sequenced at Chromous Biotech India, Bangalore. The sequences were manually edited using Chromas Lite. Species identities were established by constructing a neighbor-joining tree using MEGA V 4.0.

RESULTS

Morphological analysis of market samples revealed six different species of Phyllanthus in the trade samples. Seventy-six percent of the market samples contained Phyllanthus amarus as the predominant species (>95%) and thus were devoid of admixtures. The remaining 24% of the shops had five different species of Phyllanthus namely Phyllanthus debilis, Phyllanthus fraternus, Phyllanthus urinaria, Phyllanthus maderaspatensis, and Phyllanthus kozhikodianus. All identities, except those for Phyllanthus fraternus, were further confirmed by the species specific DNA barcode using chloroplast region psbA-trnH.

CONCLUSION

Our results show that market samples of Phyllanthus sold in southern India contain at least six different species, though among them, Phyllanthus amarus is predominant. DNA barcode, psbA-trnH region of the chloroplast can effectively discriminate Phyllanthus species and hence can be used to resolve species admixtures in the raw drug trade of Phyllanthus.

Endophytic fungal strains of Fusarium solani, from Apodytes dimidiata E. Mey. ex Arn (Icacinaceae) produce camptothecin, 10-hydroxycamptothecin and 9-methoxycamptothecin

Camptothecin and 10-hydroxycamptothecin are two important precursors for the synthesis of the clinically useful anticancer drugs, topotecan and irinotecan. In recent years, efforts have been made to identify novel plant and endophytic fungal sources of camptothecin and 10-hydroxycamptothecin. In this study we have isolated endophytic fungi strains from Apodytes dimidiata (Icacinaceae), a medium sized tree from the Western Ghats, India. The fungi were identified as Fusarium solani using both ITS rDNA sequencing and spore morphology. Two strains, MTCC 9667 and MTCC 9668 were isolated, both of which produced camptothecin and 9-methoxycamptothecin in their mycelia; one of the strains, MTCC 9668 also produced 10-hydroxycamptothecin, though in small amounts. The yields of camptothecin in MTCC 9667 and MTCC 9668 were 37 and 53 microg/100g, respectively, after 4 days of incubation in broth culture. The yields of 10-hydroxycamptothecin and 9-methoxycamptothecin in MTCC 9668 were 8.2 and 44.9 microg/100g, respectively. Further research in optimizing the culture conditions of these fungal strains might permit their application for the production of camptothecin and 10-hydroxycamptothecin.