Variation in biosynthesis of an effective anticancer secondary metabolite, mahanine in Murraya koenigii, conditional on soil physicochemistry and weather suitability.

Murraya koenigii (MK) leaf being a rich source of bioactive secondary metabolites has received inordinate attention in drug development research. Formation of secondary plant metabolite(s) in medicinal plants depends on several factors and in this study the cause of variation in bioavailability and content of a vital bioactive phytochemical, mahanine in the MK leaves from different geographical locations of varying soil properties and weather parameters was determined. Accordingly, MK leaves and soil samples around the plant base in quintuplicate from each site across five states of India at similar time point were collected. Mahanine content was determined and compared among samples from different regions. The quantitative analysis data comprised that MK-leaves of southern part of India contains highest amount of mahanine, which is 16.9 times higher than that of MK-leaves of north-eastern part of India (which measured as the lowest). The results suggested that pH, conductivity and bacterial populations of the soil samples were positively correlated with mahanine content in the MK-leaves. For examples, the average soil pH of the southern India sites was in basic range (8.8 ± 0.6); whereas that of the north-east India sites was in slightly acidic ranges (6.1 ± 0.5) and mean soil conductivity value for the north east India soils was 78.3 ± 16.3 µS/cm against mean value of 432.4 ± 204.5 µs/cm for south India soils. In conclusion, this study proclaims that higher level of bioactive phytochemical, mahanine in MK leaves depending upon geographical location, weather suitability and soil's physiochemical and microbial parameters of its cultivation sites.

Antifilarial effect of ursolic acid from Nyctanthes arbortristis: molecular and biochemical evidences.

A bio-assay guided fractionation and purification approach was used to examine in vitro antifilarial activities of the crude methanolic extract of Nyctanthes arbortristis as well as fractions and isolated compound. From ethyl-acetate fraction we isolated and identified a triterpenoid compound which has been characterized as ursolic acid (UA) by HPLC and NMR data. We are reporting for the first time isolation and identification of UA from the leaves of N. arbortristis. The crude extract and UA showed significant micro- as well as macrofilaricidal activities against the oocyte, microfilaria and adult of Setaria cervi (S. cervi) by dye exclusion test and MTT reduction assay. Significant microfilaricidal activity of UA was further proved against mf of W. bancrofti by viability assay. The findings thus provide a new lead for development of a suitable filaricide from natural products. The molecular mechanism of UA was investigated by performing TUNEL, Hoechst staining, Annexin V-Cy3, flow cytometric analysis and DNA fragmentation assay. Differential expressions of pro- and anti-apoptotic genes were observed at the transcription and translational levels in a dose-dependent manner. Depletion in the worm GSH level and elevation in the parasite GST, SOD and super oxide anion indicated the generation of ROS. In this investigation we are reporting for the first time that UA acts its antifilarial effect through induction of apoptosis and by downregulating and altering the level of some key antioxidants like GSH, GST and SOD of S. cervi.

Mahanine synergistically enhances cytotoxicity of 5-fluorouracil through ROS-mediated activation of PTEN and p53/p73 in colon carcinoma.

5-Fluorouracil (5-FU) alone or in combination with other drugs is the main basis of chemotherapeutic treatment in colorectal cancer although patients with microsatellite instability generally show resistance to 5-FU treatment. The present investigation is focussed on the mechanistic insight of a pure herbal carbazole alkaloid, mahanine, as a single or in combination with 5-FU in colon cancer. We demonstrated that mahanine-induced apoptosis involved reactive oxygen species (ROS)-mediated nuclear accumulation of PTEN and its interaction with p53/p73. Mahanine and 5-FU in combination exerted synergistic inhibitory effect on cell viability. This combination also enhanced ROS production, increased tumour suppressor proteins and suppressed chemo-migration. Taken together, our results revealed that mahanine can be a potential chemotherapeutic agent with efficacy to reduce the concentration of toxic 5-FU in colon cancer.

Bio-assay guided isolation of alpha-glucosidase inhibitory constituents from Eclipta alba.

Eclipta alba (L.) Hassk is used traditionally in diabetes mellitus in India and the plant extract is reported to possess anti-diabetic activity. A bioactivity-guided isolation approach based on alpha-glucosidase inhibition was used to identify the constituents contributing towards the inhibition of the enzyme and probably contributing towards its anti-diabetic activity. Four echinocystic acid glycosides were thus isolated, of which eclalbasaponin VI, isolated from the n-butanol fraction, was found to be the most potent (IC50 54.2 +/- 1.3 microM). The compound is an uncompetitive type of inhibitor with Ki 26.1 microM. A quantitative estimation of the constituents was established using RP-HPLC.

Effect of ferulic acid from Hibiscus mutabilis on filarial parasite Setaria cervi: molecular and biochemical approaches.

In the reported work the in vitro activity of a methanolic extract of leaves of Hibiscus mutabilis (Malvaceae) against bovine Setaria cervi worms has been investigated. Bioassay-guided fractionation led to isolation of ferulic acid from ethyl acetate fraction. The crude extract and ferulic acid, the active molecule, showed significant microfilaricidal as well as macrofilaricidal activities against the microfilaria (L(1)) and adult of S. cervi by both a worm motility and MTT reduction assay. The findings thus provide a new lead for development of a filaricidal drug from natural products. To examine the possible mechanism of action of ferulic acid, the involvement of apoptosis in adult worms of S. cervi was investigated. We found extreme cellular disturbances in ferulic acid-treated adult worms characterized by chromatin condensation, in situ DNA fragmentation and nucleosomal DNA laddering. In this work we are reporting for the first time that ferulic acid exerts its antifilarial effect through induction of apoptosis and by downregulating and altering the level of some key antioxidants (GSH, GST and SOD) of the filarial nematode S. cervi. Our results have provided experimental evidence supporting that ferulic acid causes an increased proapoptotic gene expression and decreased expression of anti-apoptotic genes simultaneously with an elevated level of ROS and gradual dose dependent decline of parasitic GSH level. We also observed a gradual dose dependent elevation of GST and SOD activity in the ferulic acid treated worms.

Hydroxychavicol, a Piper betle leaf component, induces apoptosis of CML cells through mitochondrial reactive oxygen species-dependent JNK and endothelial nitric oxide synthase activation and overrides imatinib resistance.

Alcoholic extract of Piper betle (Piper betle L.) leaves was recently found to induce apoptosis of CML cells expressing wild type and mutated Bcr-Abl with imatinib resistance phenotype. Hydroxy-chavicol (HCH), a constituent of the alcoholic extract of Piper betle leaves, was evaluated for anti-CML activity. Here, we report that HCH and its analogues induce killing of primary cells in CML patients and leukemic cell lines expressing wild type and mutated Bcr-Abl, including the T315I mutation, with minimal toxicity to normal human peripheral blood mononuclear cells. HCH causes early but transient increase of mitochondria-derived reactive oxygen species. Reactive oxygen species-dependent persistent activation of JNK leads to an increase in endothelial nitric oxide synthase-mediated nitric oxide generation. This causes loss of mitochondrial membrane potential, release of cytochrome c from mitochondria, cleavage of caspase 9, 3 and poly-adenosine diphosphate-ribose polymerase leading to apoptosis. One HCH analogue was also effective in vivo in SCID mice against grafts expressing the T315I mutation, although to a lesser extent than grafts expressing wild type Bcr-Abl, without showing significant bodyweight loss. Our data describe the role of JNK-dependent endothelial nitric oxide synthase-mediated nitric oxide for anti-CML activity of HCH and this molecule merits further testing in pre-clinical and clinical settings.

Bio-assay guided isolation of α-glucosidase inhibitory constituents from Hibiscus mutabilis leaves.

INTRODUCTION: The increasing demand for natural-product-based medicines and health-care products for the management of diabetes encouraged investigation of this commonly available Indian plant. OBJECTIVES: To establish the anti-diabetic (α-glucosidase inhibitory) activity of H. mutabilis leaf extract, isolate and identify the constituents responsible for the activity, and validate a HPLC method for quantification of the active constituents for standardisation of the extract. MATERIAL AND METHODS: The methanolic extract of leaves was partitioned between water, n-butanol and ethyl acetate. Bio-assay guided fractionation, based on inhibition of α-glucosidase, allowed isolation and identification of the active components. The active components were quantified using RP-HPLC-DAD validated for linearity, limit of detection, limit of quantification, precision, accuracy and robustness for this plant extract and the partitioned fractions. RESULTS: Ferulic acid and caffeic acid were identified as the α-glucosidase inhibitors present in H. mutabilis. They were partitioned into an ethyl acetate fraction. The HPLC-DAD calibration curve showed good linearity (r² > 0.99). For the recovery studies the %RSD was less than 2%. The interday and intraday variations were found to be less than 4% RSD for retention time and response. CONCLUSION: The identification of α-glucosidase inhibition activity in H. mutabilis supports further investigations into the possible use of the plant for the management of diabetes. The HPLC method validated for these extracts will be useful in future research with the plant.

Acridanone alkaloid in Baliospermum montanum--evaluation of its effect against anaphylaxis.

Baliospermum montanum leaves yielded 3-hydroxy-2,4-dimethoxy-10-methyl-9-acridanone (1), an alkaloid from the CHCl3 fraction. Spectroscopic analysis was performed to assign the structure of the new compound (1) and its absolute configuration. The compound was evaluated for its effect in anaphylaxis by estimation of the release of histamine in systemic anaphylaxis model. The acridanone alkaloid significantly inhibited the degranulation of mast cells up to 65.22 % and 75.12 % at a dose of 50 and 75 mg/kg, respectively.

Anti-leukemic activity of Dillenia indica L. fruit extract and quantification of betulinic acid by HPLC.

The methanolic extract of Dillenia indica L. fruits showed significant anti-leukemic activity in human leukemic cell lines U937, HL60 and K562. This finding led to fractionation of the methanolic extract, on the basis of polarity, in which the ethyl acetate fraction showed the highest anti-leukemic activity. A major compound, betulinic acid, was isolated from the ethyl acetate fraction by silica gel column chromatography and was identified and characterized. Betulinic acid could explain the anti-leukemic activity of the methanolic extract and the ethyl acetate fraction. Hence the quantitative estimation of betulinic acid was approached in methanolic extract and fractions using HPLC.

Apoptotic effects of mahanine on human leukemic cells are mediated through crosstalk between Apo-1/Fas signaling and the Bid protein and via mitochondrial pathways.

Apo-1 (Fas/CD95), a cell surface receptor, triggers apoptosis after binding to its physiological ligand, Apo-1L (FasL/CD95L). This study reports that mahanine, purified from the leaves of Murraya koenigii, has a dose- and time-dependent anti-proliferative activity in acute lymphoid (MOLT-3) and chronic myeloid (K562) leukemic cell lines and in the primary cells of leukemic and myeloid patients, with minimal effect on normal immune cells including CD34(+) cells. Leukemic cells underwent phosphatidylserine externalization and DNA fragmentation, indicating mahanine-induced apoptosis. An increase in reactive oxygen species suggests that the mahanine-induced apoptosis was mediated by oxidative stress. A significant drop in the Bcl2/Bax ratio, the loss of mitochondrial transmembrane potential as well as cytochrome c release from the mitochondria to the cytosol suggested involvement of the mitochondrial pathway of apoptosis. Cytochrome c release was followed by the activation of caspase-9, caspase-3 and caspase-7, and cleavage of PARP in both MOLT-3 and K562 cells. In MOLT-3 cells, formation of the Fas-FasL-FADD-caspase-8 heterotetramer occurred, leading to the cleavage of Bid to its truncated form, which consequently resulted in formation of the mitochondrial transmembrane pore. The incubation of MOLT-3 cells with mahanine in the presence of caspase-8 inhibitor or FasL-neutralizing NOK-2 antibody resulted in the decrease of mahanine-induced cell death. Mahanine was also a potent inhibitor of K562 xenograft growth, which was evident in an athymic nude mice model. In summary, these results provide evidence for involvement of the death receptor-mediated extrinsic pathway of apoptosis in the mahanine-induced anticancer activity in MOLT-3 cells, but not in K562 cells, which are deficient in Fas/FasL.

Corchorusin-D, a saikosaponin-like compound isolated from Corchorus acutangulus Lam., targets mitochondrial apoptotic pathways in leukemic cell lines (HL-60 and U937).

PURPOSE: The presence of triterpene saponins in Corchorus acutangulus Lam. has been reported. However, no studies concerning biological activity of the plant extracts have been done so far. In the present study, the anti-leukemic activity of the methanol extract of aerial parts (ME) of C. acutangulus has been investigated, and efforts have been made to identify the active ingredient responsible for this activity. METHODS: The anti-leukemic activity of ME, its fractions and corchorusin-D (COR-D), the active ingredient, was investigated in leukemic cell lines U937 and HL-60 using cell viability and MTT assays. The molecular pathways leading to the activity of COR-D were examined by confocal microscopy, flow-cytometry, caspase and Western blot assays. RESULTS: ME, its n-butanolic fraction and COR-D inhibited cell growth and produced significant cytotoxicity in leukemic cell lines U937 and HL-60. COR-D produced apoptotic cell death via mitochondrial disfunction and was found to pursue the intrinsic pathway by inciting the release of apoptosis-inducing factors (AIFs) from mitochondria. COR-D-induced translocation of Bax from cytosol to mitochondria facilitating caspase-9 activation and up regulation of downstream pathways leading to caspase-3 activation and PARP cleavage, which resulted in the subsequent accumulation of cells in the sub-G0 phase followed by DNA fragmentation. CONCLUSIONS: COR-D possesses significant anti-leukemic activity in U937 and HL-60 cell lines by acting on the mitochondrial apoptotic pathways. Since the necrotic body formation is low after COR-D treatment, the occurrence of inflammation in in vivo systems could be reduced, which represents a positive indication in view of therapeutic application.

Cajanus cajan Linn. (Leguminosae) prevents alcohol-induced rat liver damage and augments cytoprotective function.

AIM OF THE STUDY: Cajanus cajan Linn. (Leguminosae) is a nontoxic edible herb, widely used in Indian folk medicine for the prevention of various liver disorders. In the present study we have demonstrated that methanol-aqueous fraction (MAF2) of Cajanus cajan leaf extract could prevent the chronically treated alcohol induced rat liver damage. MATERIALS AND METHODS: Chronic doses of alcohol (3.7 g/ kg) orally administered to rats for 28 days and liver function marker enzymes such as GPT, GOT, ALP and anti-oxidant enzyme activities were determined. Effect of MAF2 at a dose of 50mg/kg body weight on alcohol treated rats was noted. RESULTS: Alcohol effected significant increase in liver marker enzyme activities and reduced the activities of anti-oxidant enzymes. Co-administration of MAF2 reversed the liver damage due to alcohol; it decreased the activities of liver marker enzymes and augmented antioxidant enzyme activities. We also demonstrate significant decrease of the phase II detoxifying enzyme, UDP-glucuronosyl transferase (UGT) activity along with a three- and two-fold decrease of UGT2B gene and protein expression respectively. MAF2 co-administration normalized UGT activity and revived the expression of UGT2B with a concomitant expression and nuclear translocation of Nrf2, a transcription factor that regulates the expression of many cytoprotective genes. CONCLUSION: Cajanus cajan extract therefore shows a promise in therapeutic use in alcohol induced liver dysfunction.