Tropical Medicinal Plant Research Articles

3β-Methoxy Derivation of Withaferin-a Attenuates its Anticancer Potency: Bioinformatics and Molecular Evidences

Withaferin A (Wi-A), a potent anticancer withanolide extracted from Withania somnifera- a tropical medicinal plant, was earlier shown to activate p53 tumor suppressor and oxidative stress pathways in cancer cells causing either growth arrest or apoptosis. In view of the information that alkyl derivatives of several bioactive steroidal compounds exhibit improved stability and activity through mechanisms that have not been completely understood, we investigated the effect of Withaferin A and its methoxy-derivative (2,3-dihydro-3- methoxy-Withaferin A) on human cancer cells to analyze the molecular interactions and efficacy. Systematic bioinformatics and molecular experimental approaches comprising expression analysis and imaging techniques were employed to demonstrate the interactions of Withaferin A and 3β-methoxy Withaferin A with their molecular targets. We demonstrate that 3β-methoxy derivation of Withaferin A possess weaker docking potential to its molecular targets and therefore possess attenuated anticancer activity as compared to Withaferin A, and was affirmed by a number of biochemical and in vitro experiments. Based on the Bioinformatics and experimental data we report that the 3β-methoxy derivation of Withaferin A attenuates its anticancer activities, and hence sufficient care is warranted in the use of these phytochemicals as anticancer reagents.

In-vitro anti-cholinesterase activity of essential oil from four tropical medicinal plants

The chemical inhibition of acetyl-cholinesterase (AChE) is a potent strategy for addressing signal related neuropathology and natural products are potential sources of compounds with such properties. Essential oil extracts from leaf, seed, stem and rhizome of four medicinal plants [Aframomum melegueta K. Schum, Crassocephalum crepidioides (Benth S. More), Monodora myristica (Gaertn.), and Ocimum gratissimum (Linn)] were tested for acetyl-cholinesterase inhibitory activity (AChEI) using Ellman's colorimentric method and compared to a reference acetyl-cholinesterase inhibitor (galantamine). The seed (IC50=6.71mg/l) and leaf (IC50=6.54mg/l) extracts from O. gratissimum showed values that matched the capacity of the reference inhibitor (IC50=6.62mg/l). The least potent extract was rhizome extracts of A. melegueta (IC50=28.97mg/l) about four times that of the reference inhibitor. Principal component analysis (PCA) showed that the intrinsic properties (bioactive ingredient factor) of each extract (PC1=29.50%) was the most important factor defining the difference or similarity in potency to the reference acetyl-cholinesterase inhibitor while ‘dose response’ (PC2=11.38%) was the second most important factor. The outstanding AChEI property of O. gratissimum extracts could largely be attributed to the high monoterpene content while the weak potency of rhizome extracts of A. melegueta may be attributed to its predominant concentrations of sesquiterpenes. Since potency could be related to interaction between bioactive components, understanding the interaction between ratios of monoterpene and sesquiterpene in extracts could be important in determining their potency for AChEI.

Quantification of asiatic acid from plant parts of Centella asiatica L. and enhancement of its synthesis through organic elicitors in in vitro

Medicinal plants are nearly unlimited source of phytochemicals. Centella asiatica L. is a tropical medicinal plant with a long history of therapeutic uses, dermal disorders, venous insufficiency micro-angiopathy, and anticancer. The present study highlights (i) in vivo evaluation of asiatic acid (as an anticancer compound) content in different plant parts of C. asiatica and (ii) in vitro elicitation of asiatic acid employing organic elicitors. Based on the HPLC analysis, the highest amount of asiatic acid (190.2 μg·g-1 fresh wt.) was found in root part in in vivo condition. Quantitative analyses were done to enhance of asiatic acid content by some organic elicitors. Results showed the highest quantity of asiatic acid content (258.3 μg·g-1 fw.) among all of the organic elicitors was found at 200 mg·L-1 yeast extract in leaf callus cultures. All these observations suggest that exogenous application of organic elicitors could have induced a subset of secondary metabolite biosynthetic genes, which may modulate expression of genes and accumulation of compounds induced by elicitors.

Antioxidant, Metal Chelating, Anti-glucosidase Activities and Phytochemical Analysis of Selected Tropical Medicinal Plants.

The purpose of this investigation was to determine the antioxidant potentials and anti-glucosidase activities of six tropical medicinal plants. The levels of phenolic constituents in these medicinal plants were also quantified and compared. Antioxidation potentials were determined colorimetrically for scavenging activities against DPPH and NO radicals. Metal chelating assay was based on the measurement of iron-ferrozine absorbance at 562 nm. Anti-diabetic potentials were measured by using α-glucosidase as target enzyme. Medicinal plants' total phenolic, total flavonoid and hydroxycinnamic acid contents were determined using spectrophotometric methods, by comparison to standard plots prepared using gallic acid, quercetin and caffeic acid standards, respectively. Radical scavenging and metal chelating activities were detected in all medicinal plants, in concentration-dependent manners. Among the six plants tested, C. nutans, C. formosana and H. diffusa were found to possess α-glucosidase inhibitory activities. Spectrophotometric analysis indicated that the total phenolic, total flavonoid and hydroxycinnamic acid contents ranged from 12.13-21.39 mg GAE per g of dry sample, 1.83-9.86 mg QE per g of dry sample, and 0.91-2.74 mg CAE per g of dry sample, respectively. Our results suggested that C. nutans and C. formosana could potentially be used for the isolation of potent antioxidants and anti-diabetic compounds. To the best of our knowledge, this study represents the first time that C. nutans (Acanthaceae family) was reported in literature with glucosidase inhibition activity.

Anti-inflammatory and antioxidant activities of Costus afer Ker Gawl. hexane leaf fraction in arthritic rat models

Ethnopharmacological relevanceCostus afer Ker Gawl is an indigenous tropical African medicinal plant used as therapy in the treatment of inflammatory ailments such as rheumatoid arthritis. This study was designed to evaluate the anti-inflammatory and antioxidant activities of the hexane fraction of C. afer leaves (CAHLF). Materials and methodsThe anti-inflammatory effect of varying doses of CAHLF on carrageenan, arachidonic acid, and formaldehyde induced arthritis in male albino rats׳ models were investigated in order to study the acute inflammatory phase. Complete Freund׳s Adjuvant (CFA)-induced arthritis model was used to study the chronic inflammatory phase. Two known anti-inflammatory drugs, Diclofenac sodium (non-steroidal anti-inflammatory drug [NSAID]) and prednisolone (glucocorticoid [steroidal drug]) were used as standards for comparison. Various biochemical indices viz. superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), reduced glutathione (GSH) and malondialdehyde (MDA), aspartate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total bilirubin (TB), total protein (TP), globulin and albumin levels were assayed using spectrophotometric methods. ResultsControl animals in which arthritis have been induced using carrageenan, arachidonic acid, formaldehyde or CFA showed significant increases (P<0.05) in paw edema when compared with normal animals. Treatment of the arthritis induced rats with CAHLF significantly (P<0.05) suppressed the edema. in vivo antioxidant study showed that CAHLF treated animals had a significantly (P<0.05) elevated GSH level, SOD, CAT and GST activities while MDA levels were significantly (P<0.05) reduced in the plasma, liver, kidney and brain. CAHLF treated rats had a significantly (P<0.05) reduced plasma AST, ALT and ALP. Plasma TP, globulin, TB levels were reduced while albumin levels were elevated in CAHLF treated animals. ConclusionsCAHLF possesses substantial anti-inflammatory and antioxidant activities against inflammatory diseases especially arthritis. It could be considered as a choice candidate in pharmaceutical anti-inflammatory drug development.

Anti-diabetic Activity of Aqueous Extracts of Vitex doniana Leaves and Cinchona calisaya Bark in Alloxan–Induced Diabetic Rats

Vitex doniana Sweet and Cinchona calisaya WEED are tropical medicinal plants endued with important pharmacological properties. The effects of aqueous extracts of V. doniana leaves and C. calisaya bark on alloxan-induced diabetes mellitus in Wistar albino rats were evaluated. Diabetes mellitus was induced by a single intraperitoneal ( i.p) injection of 150 mg/kg body wt of alloxan monohydrate. The aqueous extracts of V. doniana leaves and C. calisaya bark were administered intraperitoneally to four diabetic groups at same doses of 50 and 100 mg/kg body wt. The actions of the extracts were compared with that of the standard oral hypoglycaemic agent, glibenclamide. Both extracts caused significant (p < 0.001) decreases in blood sugar levels of the rats at both doses tested. At 50 mg/kg body wt. V. doniana leaf extract produced 82.9% reduction in blood sugar level (i.e from 492.8 to 84.5 mg/dl) after four days whereas, C. calisaya caused 64.4% decrease. Unlike C. calisaya bark, V. doniana at both doses tested, was more potent than the reference drug, glibenclamide (0.3 mg/ kg body wt.). The antidiabetic activity of V. doniana did not vary with the dose, whereas the observed effect of C. calisaya decreased with increase in dose. C. calisaya exhibited higher antidiabetic activity at a lower dose of 50 mg/kg body wt. Both medicinal plants therefore possess valuable antidiabetic property. Their effects on the antioxidant status were also investigated. V. doniana and C. calisaya extracts Research Article International Journal of TROPICAL DISEASE & Health, 2(4): 290-300, 2012 291 caused increases in the activity of SOD and lipid peroxidation when compared with control, but the increases were lower than that produced by alloxan, indicating attenuation of free radical generation. Quantitative phytochemical analyses of both extracts showed the presence of saponins(0.92%), flavonoids(7.05%), alkaloids(1.8%), and cardiac glycosides(2.8%) in V. doniana, whereas saponins(2.0%), flavonoids(5.0%), alkaloids(6.0%), and cardiac glycosides(3.54%) were detected in C. calisaya.

Hymenaea stigonocarpa Mart. ex Hayne: A tropical medicinal plant with intestinal anti-inflammatory activity in TNBS model of intestinal inflammation in rats

Ethnopharmacological relevanceStem bark and fruit pulp of Hymenaea stigonocarpa Mart ex. Hayne (Fabaceae) has been popularly used to treat inflammation and gastrointestinal diseases including ulcers, diarrhea and gastric pain. The aim of this study was to investigate the intestinal anti-inflammatory activity of a methanol extract derived from the stem bark and diet with fruit pulp of Hymenaea stigonocarpa in the TNBS model of intestinal inflammation in rats. Material and methodsThe intestinal anti-inflammatory activity of stem bark extract (100, 200 and 400mg/kg) and fruit pulp (10% and 5% in diet) was measured against the intestinal inflammatory process induced by TNBS (trinitrobenzesulphonic acid) in rats. The protective effects were evaluated as follows: evaluation of intestinal damage (damage score, extension of lesion, colon weight/length ratio), incidence of diarrhea and adherence to adjacent organs, colon glutathione (GSH) and malondialdehyde (MDA) contents, myeloperoxidase (MPO) and alkaline phosphatase (AP) activities. In addition, in vitro studies on lipid peroxidation in rat brain membranes and phytochemical profile were performed with both stem bark and fruit pulp. ResultsTreatment with 100, 200 and 400mg/kg of stem bark extract and 10% fruit pulp flour showed protective effects in the TNBS-induced colon damage, which was related to inhibition of MPO and AP activities, reduction in colon MDA content, and counteraction of GSH depletion induced by inflammatory process. A concentration-dependent inhibitory effect on the lipid peroxidation in rat brain membranes for stem bark and fruit pulp was determined, with an IC50 value of 5.25±0.23μg/mL and 27.33±0.09μg/mL, respectively. Similar phytochemical composition was observed in fruit and stem bark, including mainly flavonoids, condensed tannins and terpenes. ConclusionsStem bark extract and fruit pulp flour of Hymenaea stigonocarpa prevented TNBS-induced colonic damage in rats and this protective effect were associated to an improvement of intestinal oxidative stress. The observed anti-inflammatory and antioxidant effects may be associated to the presence of flavonoids and tannins in the stem bark and fruit pulp of Hymenaea stigonocarpa.

Antibacterial and antioxidant activities of Vaccinium corymbosum L. leaf extract

ObjectiveTo investigate antibacterial and antioxidant activity of the leaf extract of tropical medicinal herb and food plant Vaccinium corymbosum L. (V. corymbosum). MethodsFree radical scavenging activity on DPPH, ABTS, and nitrites were used to analyse phenoic and flavonoid contents of leaf extract. Other focuses included the determination of antioxidant enzymatic activity (SOD, CAT and GPx), metal chelating activity, reduction power, lipid peroxidation inhibition and the prevention of oxidative DNA damage. Antibacterial activity was determined by using disc diffusion for seven strains of bacteria. ResultsResults found that V. corymbosum leaf extract had significant antibacterial activity. The tested extract displayed the highest activity (about 23.18 mm inhibition zone) against Salmonella typhymurium and the lowest antibacterial activity was observed against Enterococcus faecalis (about 14.08 mm inhibition zone) at 10 mg/ disc. The IC50 values for DPPH, ABTS and radical scavenging activity were 0.120, 0.049 and 1.160 mg/mL, respectively. V. corymbosum leaf extract also showed dose dependent reduction power, lipid peroxidation, DNA damage prevention and significant antioxidant enzymatic activity. ConclusionsThese findings demonstrate that leaf extract of V. corymbosum could be used as an alternative therapy for antibiotic-resistant bacteria and help prevent various free radical related diseases.

Molecular cloning and functional characterization of an NADPH:cytochrome P450 reductase from a tropical medicinal plant Scoparia dulcis

Molecular cloning and functional characterization of an NADPH:cytochrome P450 reductase from a tropical medicinal plant Scoparia dulcis

Interactions of Tropical Pacific Medicinal Plants with HIV and Anti-Retroviral Drugs

Papua New Guinea (PNG) has a long tradition of medicinal plant use, employing both endemic and regional plants. PNG also has an established HIV epidemic and has instituted programs to provide anti-retroviral therapy (ART) to people living with HIV (PLH). The antagonistic or augmentative effects of herbal preparations on ART are of great concern when trying to optimize treatments for PLH. We report here an on-going, integrated study of extracts and extract fractions from more than 50 of the most commonly used PNG medicinal plants for: 1) cytotoxicity to T leukemia cells (332/1142 toxic at 50 µg/ml), 2) the ability to induce HIV in latently HIV-1 infected primary T memory cells, and in a confirmatory J-LAT T leukemia cell line (25/1542 potently active in both), 3) the ability to inhibit HIV killing of infected T leukemia cells (52/1142 active), 4) the ability to inhibit ART drug metabolizing enzymes CYP1A2 (58/132 positive), CYP3A4 (48/132 positive) and CYP2D6 (64/132 positive), and 5) the ability to induce expression of CYP1A2 and CYP3A4 (8/70 and 19/70 positive, respectively; 5 positive for both). Specific plants are identified with potent activity in selected assays, providing unequivocal rationale for caution and counseling regarding their use in combination with ART. Work supported by JTA International Sponsor Award No. 10020310 and NIH U01 TW006671.

Hepatoprotective effect of Amomum xanthoides against dimethylnitrosamine-induced sub-chronic liver injury in a rat model

Context: Amomum xanthioides Wall. ex Baker (Zingiberaceae) is a tropical medicinal plant that is commonly utilized in the treatment of digestive system disorders in Asia for a long time.Objective: This study aimed to evaluate the hepatoprotective effect and related mechanisms of A. xanthoides.Materials and methods: Sub-chronic liver injury was induced by dimethylnitrosamine (DMN, 10 mg/kg, three times per week for 3 weeks, i.p.) in rats. Water extract of A. xanthoides (WAX, 50 and 100 mg/kg) was given once a day for 3 weeks.Results and conclusion: WAX (100 mg/kg) significantly attenuated the DMN-induced excessive release of alanine aminotransferase (123.6 IU/L), aspartate aminotransferase (227.9 IU/L), alkaline phosphatase (820.9 IU/L) and total bilirubin (0.50 g/dL) in serum (p < 0.01), and hydroxyproline (30.5 mg/g tissue) and malondialdehyde (MDA) (53.6 μM/g tissue) contents (p < 0.01) in liver tissue. Furthermore, WAX significantly ameliorated the depletion of total antioxidant capacity (2.54 μM/mg tissue), superoxide dismutase (0.30 U/mg tissue), glutathione (2.10 μM/mg tissue) and catalase (605.0 U/mg tissue) activities (p < 0.05 or p < 0.01) in liver tissue. Histopathological and immunohistochemical analyses indicated that WAX markedly reduced inflammation, necrosis, collagen accumulation and activation of hepatic satellite cells in the liver. Our findings demonstrated that A. xanthoides exerts favorable hepatoprotective effects via positive regulation of the antioxidative system.

In vitro antimicrobial activity screening of tropical medicinal plants used in Santo Domingo, Dominican Republic. Part I.

Introduction: Very little is known on the uses of medicinal plants in the Caribbean island of Dominican Republic. There is a lack of scientific data supporting medicinal plant uses. The objective of the present study was to evaluate the antimicrobial activity of crude extracts of 50 medicinal plants collected from vendors at regional or municipal markets and that are used in the treatment of several types of infections in Dominican Republic. Methods: Ethanolic plant extracts were tested against five microorganisms species - Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomona aeruginosa, and Candida albicans using the disc diffusion method. Extracts were inoculated onto discs and placed on agar plates spread with microorganisms using sterile swabs. Following 24 hours of incubation at 37°C, the plates were analyzed and the zones of inhibition measured. Results and Discussion: Fourty-four of the plants tested showed inhibitory activity against one or more of the microorganisms at a 35 μg/mL extract concentration. Plants exhibiting the widest antimicrobial activity were Inga vera, Ruellia tuberosa, Calophyllum calaba, and Merremia dissecta, and were effective on at least three out the four of the bacteria tested. The test antibiotics Amikacin and Norfloxacin showed strong inhibitory activities against all bacteria but only low activity against Klebsiella pneumonia. Very few extracts showed antifungal activity against Candida albicans, however higher activity was found using Cardiospermum halicacabum extract. Conclusions: Several ethanolic extracts derived from plants used in traditional medicine in Dominican Republic possess significant antimicrobial activity against a variety of the tested microorganisms, although the mechanism(s) of action require further study.

Antioxidant and antiproliferative activities of Abrus precatorius leaf extracts--an in vitro study.

BackgroundThe use of traditional medicine at the primary health care level is widespread and plant-based treatments are being recommended for curing various diseases by traditional medical practitioners all over the world. The phytochemicals present in the fruits, vegetables and medicinal plants are getting attention day-by-day for their active role in the prevention of several human diseases. Abrus precatorius is a widely distributed tropical medicinal plant with several therapeutic properties. Therefore in the present study, A. precatorius leaf extracts were examined for their antioxidant and cytotoxic properties in vitro in order to discover resources for new lead structures or to improve the traditional medicine.MethodsIn this study, antioxidant and antiproliferative properties of the different leaf extracts (hexane, ethyl acetate, ethanol and water) from A. precatorius were investigated along with the quantification of the polyphenol and flavonoid contents. The ability of deactivating free radicals was extensively investigated with in vitro biochemical methods like DPPH•, •OH, NO, SO2- scavenging assays and inhibition capability of Fe(II)-induced lipid peroxidation. Furthermore, antiproliferative activities using different human cancer cell lines and primary cell line was carried out by MTT method.ResultsTotal phenolic content and total flavonoid content of the extracts were found in the range of 1.65 ± 0.22 to 25.48 ± 0.62 GAE mg/g dw and 6.20 ± 0.41 to 17.16 ± 1.04 QE mg/g dw respectively. The experimental results further revealed that A. precatorius extracts showed strong antiradical properties, capable to chelate Fe2+ and possess good inhibition ability of lipid peroxidation. In addition, as a first step towards the identification of phytoconstituents endowed with potent chemopreventive activities, we evaluated the inhibitory effects of A. precatorius extracts on the proliferation of four different human tumour cell lines such as human colon adenocarcinoma cells (Colo-205), human retinoblastoma cancer cells (Y79), human hepatocellular carcinoma cells (HepG2) and Leukemia cells (SupT1). Ethanol extract (APA) and ethyl acetate extract (APE) of A. precatorius had apparent capabilities of inhibiting the survival of tested human cancer cell lines. Moreover, it was observed that the A. precatorius extracts did not inhibit the growth of mice peritoneal macrophages, thus confirming that plants extracts are selective against the cancer cell lines.ConclusionThis work provides a scientific support for the high antioxidant and antiproliferative activity of this plant and thus it may find potential applications in the treatment of the diseases caused by ROS. Further studies are needed to confirm in vivo anti-tumorgenicity and subsequent chemical characterization of the active molecule(s).

A Computer Aided System for Tropical Leaf Medicinal Plant Identification

The objective of this paper is to develop a computer aided system for leaf medicinal plant identification using ProbabilisticNeural Network. In Indonesia only 20-22% of medicinal plants have been cultivated. Generally, identification process of medicinalplants has been done manually by a herbarium taxonomist using guidebook of taxonomy/dendrology. This system is designed to helptaxonomist to identify leaf medicinal plant automatically using acomputer-aided system. This system uses three features of leaf toidentify the medicinal plant, i.e., morphology, shape, and texture. Leaf is used in this system for identification because easily to find.To classify medicinal plant we used Probabilistic Neural Network. The features will be combined using Product Decision Rule (PDR).The system was tested on 30 species medicinal plant from Garden of Biopharmaca Research Center and Greenhouse Center of Exsitu Conservation of Medicinal Indonesian Tropical Forest Plants, Faculty of Forestry, Bogor Agriculture University, Indonesia.Experiment results showed that the accuracy of medicinal plant identification using combination of leaf features increase until74,67%.The comparative analysis of leaf features has been performed statistically. It showed that shape is a dominant features for plant identification. This system is very promising to help people identify medicinal plant automatically and for conservation and utilization of medicinal plants.

Oral administration of fingerroot (Boesenbergia pandurata) extract reduces ultraviolet b-induced skin aging in hairless mice

Fingerroot [Boesenbergia pandurata (Roxb.) Schltr.], belonging to Zingiberaceae, is an edible tropical medicinal plant that has been traditionally used to treat various diseases. However, the effect of its oral intake on skin has not yet been reported. This study aimed to investigate anti-photoaging effects of the ethanol extract of fingerroot in a hairless mouse model. Compared with the untreated UVB control group, mice that received fingerroot extract (BPE) showed significantly reduced wrinkle formation, skin thickening, and transepidermal water loss in dorsal skin irradiated with UVB. Moreover, BPE significantly prevented UVB-induced matrix metalloproteinase (MMP)-3 and -13 expressions and also MMP-2 and -9 activities. These results strongly suggest that oral administration of BPE confers in vivo anti-photoaging effects in hairless mice. Thus, fingerroot may have potential as an oral photoprotective agent to prevent skin photoaging following UV exposure.

Emergência e crescimento inicial de plântulas de Caesalpinia ferrea Mart. ex Tul. var. ferrea em diferentes substratos

Juca (Caesalpinia ferrea Mart. ex Tul. var. ferrea) is a tropical leguminous tree and medicinal plant used as forage in northeastern Brazil, so the aim of this study was to evaluate the influence of substrates in the emergence and early growth of seedlings of C. ferrea. The experimental design was completely randomized with ten treatments, which were: S1 - sand, S2 - vermiculite, S3 - hortimix®, S4 - sand + vermiculite (1:1), S5 - sand + vermiculite (2:1), S6 - hortimix® + sand (1:1), S7 - hortimix ® + sand (2:1), S8 - hortimix® + vermiculite (1:1), S9 - hortimix® + vermiculite (2:1) and S10 - sand + vermiculite + hortimix® (1:1:1), in four replicates of 25 seeds. The percentage of survival, percentage and index of emergence speed, height, root length and seedling dry matter were evaluated. The highest percentage of emergence occurred in substrates S1, S2, S4, S5 and S8 while the percentage of emerged seedlingsurvival was 100% in all substrates. The greater seedling height occurred in substrates S2 and S8, respectively. The main root length and seedling dry weight occurred in the substrate S2. For the emergence tests sand substrate is recommended and for production of seedlings vermiculite.

Antimicrobial activity of &lt;i&gt;Carpolobia lutea&lt;/i&gt; extracts and fractions

Carpolobia lutea (G. Don) (Polygalaceae) is a tropical medicinal plant putative in traditional medicines against gonorrhea, gingivitis, infertility, antiulcer and malaria. The present study evaluated the antimicrobial, antifungal and antihelicobacter effects of extracts C. lutea leaf, stem and root. The extracts were examined using the disc-diffusion and Microplates of 96 wells containing Muller-Hinton methods against some bacterial strains: Eschericia coli (ATCC 25922), E. coli (ATCC10418), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Staphyllococus aureus (ATCC 6571), Enterococcus faecalis (ATCC 29212) and Bacillus subtilis (NCTC 8853) and four clinical isolates: one fungi (Candida albican) and three bacteria (Salmonella, Sheigella and staphylococcus aureus). The Gram-positive bacteria: Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Bacillus subtilis (ATCC 19659) and the Gram-negative bacteria: Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Cândida albicans (ATCC 18804) and Helicobacter pylori (ATCC 43504). Some of these extracts were found to be active against some tested strains but activity against H. pylori was >1000mg/ml and good fungistatic activity against C. albican. The MIC against C. albican is in the order n-HF > CHF > ETF= EAF.The order of potency of fraction was the ethanol root > n-HF leaf > ethanol fraction stem > chloroform fraction leaf = ethyl acetate fraction leaf. Polyphenols were demonstrated in ethanol fraction, ethyl acetate fraction, crude ethyl acetate extract and ethanol extract, respectively. These polyphenols isolated may partly explain and support the use of C. lutea for the treatment of infectious diseases in traditional Ibibio medicine of Nigeria.

Abundant and diverse endophytic actinobacteria associated with medicinal plant Maytenus austroyunnanensis in Xishuangbanna tropical rainforest revealed by culture‐dependent and culture‐independent methods

Endophytes are now considered as an important component of biodiversity. However, the diversity of endophytic actinobacteria associated with tropical rainforest native medicinal plants is essentially unknown. In this study, the diversity of endophytic actinobacteria residing in root, stem and leaf tissues of medicinal plant Maytenus austroyunnanensis collected from tropical rainforest in Xishuangbanna, China was investigated with a combination of cultivation and culture-independent analysis on the basis of 16S rRNA gene sequencing. By using different selective isolation media and methods, a total of 312 actinobacteria were obtained, and they were affiliated with the order Actinomycetales (distributed into 21 genera). Based on a protocol for endophytes enrichment, three 16S rRNA gene clone libraries were constructed and 84 distinct operational taxonomic units were identified and they distributed among the orders Actinomycetales and Acidimicrobiales, including eight suborders and at least 38 genera with a number of rare actinobacteria genera. Phylogenetic analysis showed that 32% of the clones in the libraries had lower than 97% similarities with related type strains. Interestingly, six genera from the order Actinomycetales and uncultured clones from Acidimicrobiales have not, to our knowledge, been previously reported as endophytes. Our study confirms abundant endophytic actinobacterial consortium in tropical rainforest native plant and suggests that this special habitat represents an underexplored reservoir of diverse and novel actinobacteria of potential interest for bioactive compounds discovery.

In vitro modulation of oxidative burst via release of reactive oxygen species from immune cells by extracts of selected tropical medicinal herbs and food plants

ObjectiveTo evaluate in vitro immunomodulating properties and potential cytotoxicity of six tropical medicinal herbs and food plants namely Antidesma madagascariense (Euphorbiaceae) (AM), Erythroxylum macrocarpum (Erythroxylaceae) (EM), Faujasiopsis flexuosa (Asteraceae) (FF), Pittosporum senacia (Pittosporaceae) (PS), Momordica charantia (Cucurbitaceae) (MC) and Ocimum tenuiflorum (Lamiaceae) (OT). MethodsInitially, the crude water and methanol extracts were probed for their capacity to trigger immune cells' NADPH oxidase and MPO-dependent activities as measured by lucigenin- and luminol-amplified chemiluminescence, respectively; as compared to receptor-dependent (serum opsonised zymosan- OPZ) or receptor-independent phorbol myristerate acetate (PMA). ResultsPreliminary screening on whole human blood oxidative burst activity showed significant and concentration-dependent immunomodulating properties of three plants AM, FF and OT. Further investigations of the fractions on isolated human polymorphonuclear cells (PMNs) and mice monocytes using two different pathways for activation of phagocytic oxidative burst showed that ethyl acetate fraction was the most potent extract. None of the active samples had cell-death effects on human PMNs, under the assay conditions as determined by the trypan-blue exclusion assay. Since PMA and OPZ NADPH oxidase complex is activated via different transduction pathways, these results suggest that AM, FF and OT does not affect a specific transductional pathway, but rather directly inhibit a final common biochemical target such as the NADPH oxidase enzyme and/or scavenges ROS. ConclusionsOur findings suggest that some of these plants extracts/fractions were able to modulate significantly immune response of phagocytes and monocytes at different steps, emphasizing their potential as a source of new natural alternative immunomodulatory agents.

Diversity of endophytic fungi in some tropical medicinal plants – A report

Endophytic fungi are a taxonomically and ecologically heterogenous group of organisms; mainly belong to ascomycetes, coelomycetes and hypomycetes. The abundance of endophytic fungi in tropical regions has been studied. However, scant attentions have been given to medicinal plants of tropics. Synthesis of Indole acetic acid and metabolites showing antiviral, volatile metabolites, anticancer agents, anti-oxidants, insecticidal activities, antidiabetic and immunosuppressive compounds are widespread among the endophytic fungi. Now, more concentration has been given to the chemistry and bioactive compounds of endophytic fungi, mycodiversity and their ecological role. This review deals with the brief survey of the endophytic fungi of some medicinal hosts and their bioactive compounds characterized. Key words: Ascomycetes, coelomycetes, ecology, hypomycetes, secondary metabolites, and tropical.