Accessing chemical diversity from the uncultivated symbionts of small marine animals.

Chemistry drives many biological interactions between the microbiota and host animals, yet it is often challenging to identify the chemicals involved. This poses a problem, as such small molecules are excellent sources of potential pharmaceuticals, pretested by nature for animal compatibility. We discovered anti-HIV compounds from small, marine tunicates from the Eastern Fields of Papua New Guinea. Tunicates are a reservoir for new bioactive chemicals, yet their small size often impedes identification or even detection of the chemicals within. We solved this problem by combining chemistry, metagenomics, and synthetic biology to directly identify and synthesize the natural products. We show that these anti-HIV compounds, the divamides, are a novel family of lanthipeptides produced by symbiotic bacteria living in the tunicate. Neighboring animal colonies contain structurally related divamides that differ starkly in their biological properties, suggesting a role for biosynthetic plasticity in a native context wherein biological interactions take place.

Traditional Preparations and Methanol Extracts of Medicinal Plants from Papua New Guinea Exhibit Similar Cytochrome P450 Inhibition.

The hypothesis underlying this current work is that fresh juice expressed from Papua New Guinea (PNG) medicinal plants (succus) will inhibit human Cytochrome P450s (CYPs). The CYP inhibitory activity identified in fresh material was compared with inhibition in methanol extracts of dried material. Succus is the most common method of traditional medicine (TM) preparation for consumption in PNG. There is increasing concern that TMs might antagonize or complicate drug therapy. We have previously shown that methanol extracts of commonly consumed PNG medicinal plants are able to induce and/or inhibit human CYPs in vitro. In this current work plant succus was prepared from fresh plant leaves. Inhibition of three major CYPs was determined using human liver microsomes and enzyme-selective model substrates. Of 15 species tested, succus from 6/15 was found to inhibit CYP1A2, 7/15 inhibited CYP3A4, and 4/15 inhibited CYP2D6. Chi-squared tests determined differences in inhibitory activity between succus and methanol preparations. Over 80% agreement was found. Thus, fresh juice from PNG medicinal plants does exhibit the potential to complicate drug therapy in at risk populations. Further, the general reproducibility of these findings suggests that methanol extraction of dried material is a reasonable surrogate preparation method for fresh plant samples.

An ethnobotanical survey of medicinal plants used in the East Sepik province of Papua New Guinea.

BACKGROUND: Rapid modernization in the East Sepik (ES) Province of Papua New Guinea (PNG) is resulting in a decrease in individuals knowledgeable in medicinal plant use. Here we report a synthesis and comparison of traditional medicinal plant use from four ethnically distinct locations in the ES Province and furthermore compare them to two other previous reports of traditional plant use from different provinces of PNG. METHODS: This manuscript is based on an annotated combination of four Traditional Medicines (TM) survey reports generated by University of Papua New Guinea (UPNG) trainees. The surveys utilized a questionnaire titled "Information sheet on traditional herbal preparations and medicinal plants of PNG", administered in the context of the TM survey project which is supported by WHO, US NIH and PNG governmental health care initiatives and funding. Regional and transregional comparison of medicinal plant utilization was facilitated by using existing plant databases: the UPNG TM Database and the PNG Plant Database (PNG Plants) using Bayesian statistical analysis. RESULTS: Medicinal plant use between four distinct dialect study areas in the ES Province of PNG showed that only a small fraction of plants had shared use in each area, however usually utilizing different plant parts, being prepared differently and to treat different medical conditions. Several instances of previously unreported medicinal plants could be located. Medicinally under- and over-utilized plants were found both in the regional reports and in a transregional analysis, thus showing that these medicinal utilization frequencies differ between provinces. CONCLUSIONS: Documentation of consistent plant use argues for efficacy and is particularly important since established and effective herbal medicinal interventions are sorely needed in the rural areas of PNG, and unfortunately clinical validation for the same is often lacking. Despite the existence of a large corpus of medical annotation of plants for PNG, previously unknown medical uses of plants can be uncovered. Furthermore, comparisons of medicinal plant utilization is possible if databases are reformatted for consistencies that allow comparisons. A concerted effort in building easily comparable databases could dramatically facilitate ethnopharmacological analysis of the existing plant diversity.

Isolation of pyrrolocins A-C: cis- and trans-decalin tetramic acid antibiotics from an endophytic fungal-derived pathway.

Three new decalin-type tetramic acid analogues, pyrrolocins A (1), B (2), and C (3), were defined as products of a metabolic pathway from a fern endophyte, NRRL 50135, from Papua New Guinea. NRRL 50135 initially produced 1 but ceased its production before chemical or biological evaluation could be completed. Upon transfer of the biosynthetic pathway to a model host, 1-3 were produced. All three compounds are structurally related to equisetin-type compounds, with 1 and 3 having a trans-decalin ring system, while 2 has a cis-fused decalin. All were active against Mycobacterium tuberculosis, with the trans-decalin analogues 1 and 3 exhibiting lower MICs than the cis-decalin analogue 2. Here we report the isolation, structure elucidation, and antimycobacterial activities of 1-3 from the recombinant expression as well as the isolation of 1 from the wild-type fungus NRRL 50135.

Interactions of Papua New Guinea medicinal plant extracts with antiretroviral therapy.

ETHNOPHARMACOLOGICAL RELEVANCE: A substantial proportion of the population in Papua New Guinea (PNG) lives with human immunodeficiency virus (HIV). Treatment requires lifelong use of antiretroviral therapy (ART). The majority of people in PNG use traditional medicines (TM) derived from plants for all types of health promotions. Consequently, there is a concern that herb-drug interactions may impact the efficacy of ART. Herb-drug, or drug-drug, interactions occur at the level of metabolism through two major mechanisms: enzyme induction or enzyme inhibition. In this study, extracts of commonly-used medicinal plants from PNG were screened for herb-drug interactions related to cytochrome P450s (CYPs). MATERIALS AND METHODS: Sixty nine methanol extracts of TM plants were screened for their ability to induce CYPs by human aryl hydrocarbon receptor- (hAhR-) and human pregnane X receptor- (hPXR-) dependent mechanisms, utilizing a commercially available cell-based luciferase reporter system. Inhibition of three major CYPs, CYP1A2, CYP3A4, and CYP2D6, was determined using human liver microsomes and enzyme-selective model substrates. RESULTS: Almost one third of the TM plant extracts induced the hAhR-dependent expression of CYP1A2, the hPXR-dependent expression of CYP3A4, or both. Almost two thirds inhibited CYP1A2, CYP3A4, or CYP2D6, or combinations thereof. Many plant extracts exhibited both induction and inhibition properties. CONCLUSIONS: We demonstrated that the potent and selective ability of extracts from PNG medicinal plants to affect drug metabolizing enzymes through induction and/or inhibition is a common phenomenon. Use of traditional medicines concomitantly with ART could dramatically alter the concentrations of antiretroviral drugs in the body; and their efficacy. PNG healthcare providers should counsel HIV patients because of this consequence.

4-Quinolone alkaloids from Melochia odorata.

The methanol extract of Melochia odorata yielded three 4-quinolone alkaloids including waltherione A (1) and two new alkaloids, waltherione C (2) and waltherione D (3). Waltheriones A and C showed significant activities in an in vitro anti-HIV cytoprotection assay at concentrations of 56.2 and 0.84 µM and inhibition of HIV P24 formation of more than 50% at 1.7 and 0.95 µM, respectively. The structures of the alkaloids were established by spectroscopic data interpretation.

Myristicyclins A and B: antimalarial procyanidins from Horsfieldia spicata from Papua New Guinea.

An antimalarial screen for plants collected from Papua New Guinea identified an extract of Horsfieldia spicata as having activity. Isolation of the active constituents led to the identification of two new compounds: myristicyclins A (1) and B (2). Both compounds are procyanidin-like congeners of myristinins lacking a pendant aromatic ring. Myristicyclin A was found to inhibit the ring, trophozoite, and schizont stages of Plasmodium falciparum at similar concentrations in the mid-µM range.

Single-molecule inhibition of human kinesin by adociasulfate-13 and -14 from the sponge Cladocroce aculeata.

Two merotriterpenoid hydroquinone sulfates designated adociasulfate-13 (1) and adociasulfate-14 (2) were purified from Cladocroce aculeata (Chalinidae) along with adociasulfate-8. All three compounds were found to inhibit microtubule-stimulated ATPase activity of kinesin at 15 µM by blocking both the binding of microtubules and the processive motion of kinesin along microtubules. These findings directly show that substitution of the 5'-sulfate in 1 for a glycolic acid moiety in 2 maintains kinesin inhibition. Nomarski imaging and bead diffusion assays in the presence of adociasulfates showed no signs of either free-floating or bead-bound adociasulfate aggregates. Single-molecule biophysical experiments also suggest that inhibition of kinesin activity does not involve adociasulfate aggregation. Furthermore, both mitotic and nonmitotic kinesins are inhibited by adociasulfates to a significantly different extent. We also report evidence that microtubule binding of nonkinesin microtubule binding domains may be affected by adociasulfates.

Plakinamine M, a steroidal alkaloid from the marine sponge Corticium sp.

By means of bioassay-guided fractionation, a new steroidal alkaloid, plakinamine M (1), and the known compound, plakinamine L (2), with a unique acyclic side chain, were isolated from the marine sponge Corticium sp. collected from New Britain, Papua New Guinea. The structures were determined on the basis of extensive 1D and 2D NMR and HRESIMS. The two compounds showed inhibition of Mycobacterium tuberculosis with MIC values of 15.8 and 3.6 µg/mL, respectively.

An ethnobotanical survey of medicinal plants used in the eastern highlands of Papua New Guinea.

BACKGROUND: The Eastern Highlands area of Papua New Guinea (PNG) has a rich tradition of medicinal plant use. However, rapid modernization is resulting in the loss of independent language traditions and consequently a loss of individuals knowledgeable in medicinal plant use. This report represents a program to document and preserve traditional knowledge concerning medicinal plant use in PNG. This report documents and compares traditional plant use in the Eastern Highlands districts of Unggai-Bena, Okapa, and Obura-Wonenara, and puts these new records in context of previously documented PNG medicinal plant use. METHODS: This manuscript is an annotated combination of Traditional Medicines survey reports generated by UPNG trainees using a survey questionnaire titled "Information sheet on traditional herbal reparations and medicinal plants of PNG". The Traditional Medicines survey project is supported by WHO, US NIH and PNG governmental health care initiatives and funding. RESULTS: Overall, after "poisoning" (synonymous with "magic") the most commonly recorded ailments addressed by medicinal plant use were pain, gynecological disease, gastrointestinal maladies, anemia or malnutrition and malaria. However, the recorded indications for plant use varied widely amongst the different survey locations. Unlike many areas of PNG, mixing of ingredients was the most common mode of preparation recorded, except for two areas where the consumption of fresh plant material was more common. Throughout the Eastern Highlands oral administration was most common, with topical application second. Overall, leaves were most commonly used in the preparations of the healers interviewed, followed by bark and stems. Several new medicinal uses of plants were also documented. CONCLUSIONS: Collaboration between the WHO, UPNG and the PNG Department of Health initiated Traditional Medicine survey program in order to preserve traditional knowledge concerning medicinal plant use in PNG. This effort promotes integration of effective and accessible traditional practices with Western protocols. The Traditional Medicine surveys are particularly important because, in the absence of the clinical validation, the documentation of the consistent use of a given plant for specific indication by a large number of herbalists, across a wide range of ethnic traditions, maybe considered as a positive criterion for the promulgation of said use amongst PNG's recently formed traditional healer associations.

An ethnobotanical survey of medicinal plants used in the Siwai and Buin districts of the Autonomous Region of Bougainville.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional knowledge of medicinal plant use in many regions of Papua New Guinea and the Autonomous Region of Bougainville is poorly described and rapidly disappearing. A program initiated by the University of Papua New Guinea to systematically document and preserve traditional knowledge of medicinal plant use was initiated with WHO help in 2001. AIM OF THE STUDY: To document and compare medicinal plant use in the Siwai and Buin districts of the Island of Bougainville. Siwai and Buin districts represent two adjacent geographic regions of differing language traditions. MATERIALS AND METHODS: This report is a combination of two University of Papua New Guinea reports generated using a University of Papua New Guinea and Papua New Guinea Department of Health approved survey questionnaire "Information sheet on traditional herbal reparations and medicinal plants of Papua New Guinea". RESULTS: Although Siwai and Buin districts are adjacent in Southern Bougainville, there is considerable variation in the specific plants used medicinally and the specific uses of those plants that are used commonly in the two regions. In addition, many of the plants used in the region are widely distributed species that are used medicinally in other settings. Nevertheless, the high endemicity of plants and the extraordinary cultural diversity in the Autonomous Region of Bougainville has yielded description of the medicinal use of many plants that have not previously been reported in the wider scientific literature. CONCLUSIONS: Efforts to document and preserve traditional knowledge of plant use in Papua New Guinea have yielded important new records of plants with potential application in the provision of health care for a developing nation with an under developed Western style rural health care system. This report documents substantial commonality in the general modes of medicinal plant preparation and in the health care applications of plant use in the Siwai and Buin traditions, however, there was considerable difference noted in the particular uses of the specific plants used in one or another of the districts.